Optimization of Cognitive Radio System Using Enhanced Firefly Algorithm

The optimization of cognitive radio(CR)system using an enhanced firefly algorithm(EFA)is presented in this work.The Firefly algorithm(FA)is a nature-inspired algorithm based on the unique light-flashing behavior of fireflies.It has already proved its competence in various optimization prob-lems,but it suffers from slow convergence issues.To improve the convergence performance of FA,a new variant named EFA is proposed.The effectiveness of EFA as a good optimizer is demonstrated by optimizing benchmark functions,and simulation results show its superior performance compared to biogeography-based optimization(BBO),bat algorithm,artificial bee colony,and FA.As an application of this algorithm to real-world problems,EFA is also applied to optimize the CR system.CR is a revolutionary technique that uses a dynamic spectrum allocation strategy to solve the spectrum scarcity problem.However,it requires optimization to meet specific performance objectives.The results obtained by EFA in CR system optimization are compared with results in the literature of BBO,simulated annealing,and genetic algorithm.Statistical results further prove that the proposed algorithm is highly efficient and provides superior results.

Driver Intent Prediction and Collision Avoidance With Barrier Functions

For autonomous vehicles and driver assist systems,path planning and collision avoidance algorithms benefit from accurate predictions of future location of other vehicles and intent of their drivers.In the literature,the algorithms that provide driver intent belong to two categories:those that use physics based models with some type of filtering,and machine learning based approaches.In this paper we employ barrier functions(BF)to decide driver intent.BFs are typically used to prove safety by establishing forward invariance of an admissible set.Here,we decide if the“target”vehicle is violating one or more possibly fictitious(i.e.,non-physical)barrier constraints determined based on the context provided by the road geometry.The algorithm has a very small computational footprint and better false positive and negative rates than some of the alternatives.The predicted intent is then used by a control barrier function(CBF)based collision avoidance system to prevent unnecessary interventions,for either an autonomous or human-driven vehicle.

Atrial fibrillation in obstructive sleep apnea

Atrial fibrillation(AF) is a common arrhythmia with rising incidence.Obstructive sleep apnea(OSA) is prevalent among patients with AF.This observation has prompted significant research in understanding the relationship between OSA and AF.Multiple studies support a role of OSA in the initiation and progression of AF.This association has been independent of obesity,body mass index and hypertension.Instability of autonomic tone and wide swings in intrathoracic pressure are seen in OSA.These have been mechanistically linked to initiation of AF in OSA patients by lowering atrial effective refractory period,promoting pulmonary vein discharges and atrial dilation.OSA not only promotes initiation of AF but also makes management of AF difficult.Drug therapy and electrical cardioversion for AF are less successful in presence of OSA.There has been higher rate of early and overall recurrence after catheter ablation of AF in patients with OSA.Treatment of OSA with continuous positive airway pressure has been shown to improve control of AF.However,additional studies are needed to establish a stronger relationship between OSA treatment and success ofAF therapies.There should be heightened suspicion of OSA in patients with AF.There is a need for guidelines to screen for OSA as a part of AF management.

New technologies to investigate the brain-gut axis

Functional gastrointestinal disorders are commonly encountered in clinical practice, and pain is their commonest presenting symptom. In addition, patients with these disorders often demonstrate a heightened sensitivity to experimental visceral stimulation, termed visceral pain hypersensitivity that is likely to be important in their pathophysiology. Knowledge of how the brain processes sensory information from visceral structures is still in its infancy. However, our understanding has been propelled by technological imaging advances such as functional Magnetic Resonance Imaging, Positron Emission Tomography, Magnetoencephalography, and Electroencephalography （EEG）. Numerous human studies have non-invasively demonstrated the complexity involved in functional pain processing, and highlighted a number of subcortical and cortical regions involved. This review will focus on the neurophysiological pathways （primary afferents, spinal and supraspinal transmission）, brainimaging techniques and the influence of endogenous and psychological processes in healthy controls and patients suffering from functional gastrointestinal disorders. Special attention will be paid to the newer EEG source analysis techniques. Understanding the phenotypic differences that determine an individual＇s response to injurious stimuli could be the key to understanding why some patients develop pain and hyperalgesia in response to inflammation/injury while others do not. For future studies, an integrated approach is required incorporating an individual＇s psychological, autonomic, neuroendocrine, neurophysiological, and genetic profile to define phenotypic traits that may be at greater risk of developing sensitised states in response to gut inflammation or injury.

A comparative study on microstructural evolution and surface properties of graphene/CNT reinforced Al6061-SiC hybrid surface composite fabricated via friction stir processing

A comparative study on the surface properties of Al-SiC-multi walled carbon nanotubes (CNT) and Al-SiC-graphene nanoplatelets (GNP) hybrid composites fabricated via friction stir processing (FSP) was documented. Microstructural characterization reveals a more homogeneous dispersion of GNPs in the Al matrix as compared to CNTs. Dislocation blockade by SiC and GNP particles along with the defect-free interface between the matrix and reinforcements is also observed. Nanoindentation study reveals a remarkable ~207% and ~27% increment in surface nano-hardness of Al-SiC-GNP and Al-SiC-CNT hybrid composite compared to as-received Al6061 alloy, respectively. On the other hand, the microhardness values of Al-SiC-GNP and Al-SiC-CNT are increased by ~36% and ~17% relative to as-received Al6061 alloy, respectively. Tribological assessment reveals ~56% decrease in the specific wear rate of Al-SiC-GNP hybrid composite, whereas it is increased by ~122% in Al-SiC-CNT composite. The higher strength of Al-SiC-GNP composite is attributed to the mechanical exfoliation of GNPs to few layered graphene (FLG) in the presence of SiC. Also, various mechanisms such as thermal mismatch, grain refinement, and Orowan looping contribute significantly towards the strengthening of composites. Moreover, the formation of tribolayer by the squeezed-out GNP on the surface is responsible for the improved tribological performance of the composites. Raman spectroscopy and various other characterization methods corroborate the results.

Erythropoietin therapy after out-of-hospital cardiac arrest:A systematic review and meta-analysis

AIM To assess safety and efficacy of early erythropoietin(Epo) administration in patients with out-of-hospital cardiac arrest(OHCA).METHODS A systematic literature search was performed using PubM ed,MEDLINE,EMBASE,EBSCO,CINAHL,Web of Science and Cochrane databases,of all studies published from the inception through October 10,2016.Inclusion criteria included:(1) Adult humans with OHCA and successful sustained return of spontaneous circulation;and(2) studies including mortality/brain death,acute thrombotic events as their end points.Primary efficacyoutcome was "brain death or Cerebral Performance Category(CPC) score of 5".Secondary outcomes were "CPC score 1,and 2-4","overall thrombotic events" and "acute coronary stent thrombosis".RESULTS We analyzed a total of 606 participants(n = 276 received Epo and n = 330 with standard of care alone) who experienced OHCA enrolled in 3 clinical trials.No significant difference was observed between the Epo and no Epo group in brain death or CPC score 5(OR = 0.77;95%CI:0.42-1.39),CPC score 1(OR = 1.16,95%CI:0.82-1.64),and CPC score 2-4(OR = 0.77,95%CI:0.44-1.36).Epo group was associated with increased thrombotic complications(OR = 2.41,95%CI:1.26-4.62) and acute coronary stent thrombosis(OR = 8.16,95%CI:1.39-47.99).No publication bias was observed.CONCLUSION Our study demonstrates no improvement in neurological outcomes and increased incidence of thrombotic events and acute coronary stent thrombosis in OHCA patients who were treated with Epo in addition to standard therapy.

Obesity paradox in patients undergoing coronary intervention:A review

There is strong relationship between obesity and cardiovascular disease including coronary artery disease(CAD). However, the literature has shown better outcomes in higher obese patients who undergo percutaneous cardiovascular interventions for CAD, a phenomenon known as the obesity paradox(OX). In this review, we performed extensive search for OX in patients undergoing percutaneous coronary intervention. We also discussed possible mechanism OX and disparities in different race and sex.

Chemotherapy induced Takotsubo cardiomyopathy

Chemotherapy has been linked with Takotsubo cardiomyopathy. Most of the literature on chemotherapy associated Takotsubo cardiomyopathy is on the drug 5-fluorouracil. In this report, we describe the case of a 55-year-old Asian male who developed Takotsubo cardiomyopathy while receiving dual chemotherapy with cytarabine and daunorubicin for acute myeloid leukemia. To our knowledge, it is the first case of Takotsubo cardiomyopathy associated with daunorubicin and/or cytarabine.

Speed-Direction Sensing under Multiple Vehicles Scenario Using Photonic Radars

Recent reports from World Health Organization(WHO)show the impact of human negligence as a serious concern for road accidents and casualties worldwide.There are number of reasons which led to this negligence;hence,need of intelligent transportation system(ITS)gains more attention from researchers worldwide.For achieving such autonomy different sensors are involved in autonomous vehicles which can sense road conditions and warn the control system about possible hazards.This work is focused on designing one such sensor system which can detect and range multiple targets under the impact of adverse atmospheric conditions.A high-speed Linear Frequency Modulated Continuous Wave(LFMCW)based Photonic Radar is proposed to detect multiple targets by integrating Mode division multiplexing(MDM).Reported results in terms of range frequency,Doppler frequency and range resolution are demonstrated using numerical simulations with the bandwidths of 1 and 4 GHz and under adverse atmospheric conditions carrying 75 dB/km of attenuation.To prove the effectiveness of the proposed photonic radar,moving targets are also demonstrated with different speed.System reported substantial range resolution of 15 cm using 1 GHz of bandwidth and 3 cm using 4 GHz of bandwidth.

Green Approach for <i>In-Situ</i>Growth of CdS Nanorods in Low Band Gap Polymer Network for Hybrid Solar Cell Applications

In-situ growth of CdS nanorods (NRs) has been demonstrated via solvothermal, in a low band gap polymer, poly [[4,8-bis[(2-ethylhexyl)oxy] benzo [1,2-b:4,5-b’] dithiophene-2,6-diyl] [3-fluoro-2-[(2-ethylhexyl) carbonyl] thieno [3,4-b] thiophenediyl]] (PTB7). It is a high yielding, green approach as it removes use of volatile and hazardous chemicals such as pyridine as ligand which are conventionally used to synthesize precursors of CdS (NRs). Moreover the solvothermal process is a zero emission process being a close vessel synthesis and hence no material leaching into the atmosphere during the synthesis. The PTB7:CdS nanocomposite has been characterized by SEM, XRD, FTIR, UV-visible spectroscopy techniques. The photoluminescence (PL) spectroscopy study of PTB7 with CdS NRs has shown significant PL quenching by the incorporation of CdS NRs in PTB7;this shows that CdS NRs are efficient electron acceptors with the PTB7. The PTB7:CdS is used as active layer in the fabrication of hybrid solar cells (HSC) as donor-acceptor combination in the bulk heterojunction (BHJ) geometry. The HSCs fabricated using this active layer without any additional supporting fullerene based electron acceptor has given power conversion efficiency of above 1%.

A review on co-pyrolysis of agriculture biomass and disposable medical face mask waste for green fuel production:recent advances and thermo-kinetic models

The Association of Southeast Asian Nations is blessed with agricultural resources,and with the growing population,it will continue to prosper,which follows the abundance of agricultural biomass.Lignocellulosic biomass attracted researchers’interest in extracting bio-oil from these wastes.However,the resulting bio-oil has low heating values and undesirable physical properties.Hence,co-pyrolysis with plastic or polymer wastes is adopted to improve the yield and quality of the bio-oil.Furthermore,with the spread of the novel coronavirus,the surge of single-use plastic waste such as disposable medical face mask,can potentially set back the previous plastic waste reduction measures.Therefore,studies of existing technologies and techniques are referred in exploring the potential of disposable medical face mask waste as a candidate for co-pyrolysis with biomass.Process parameters,utilisation of catalysts and technologies are key factors in improving and optimising the process to achieve commercial standard of liquid fuel.Catalytic copyrolysis involves a series of complex mechanisms,which cannot be explained using simple iso-conversional models.Hence,advanced conversional models are introduced,followed by the evolutionary models and predictive models,which can solve the non-linear catalytic copyrolysis reaction kinetics.The outlook and challenges for the topic are discussed in detail.