Sharif Digital Repository

An adaptive tracker to address the problem of tracking objects which undergo abrupt and significant motion changes is introduced. Abrupt motion of objects is an issue which makes tracking a challenging task. To address this problem, a new adaptive motion model is proposed. The model is integrated into the sequential importance resampling particle filter (SIR PF), which is the most popular probabilistic tracking framework. In this model, in each time step, if necessary, the particles' configurations are updated by using feedback information from the observation likelihood. In order to overcome the local-trap problem, local search algorithm with best improvement strategy is used to update... 

High-performance wearable electronic devices with the capability of converting mechanical force into electrical energy have been gaining increasing attention for biomedical monitoring applications. We present a novel wearable piezoelectric sensor based on a poly(vinylidene fluoride) (PVDF) nanofibrous membrane containing microporous zirconium-based metal-organic frameworks (MOFs) for arterial pulse monitoring. It is shown that the incorporation of 5 wt % of MOF greatly enhances the piezoelectric constant of the polymer fibrous mat by 3.4-fold without significant loss in its flexibility. The nanofibrous composite exhibits a peak-to-peak voltage of 600 mV under an applied force of 5 N, which... 

Fuzzy connectedness and fuzzy clustering are two well-known techniques for fuzzy image segmentation. The former considers the relation of pixels in the spatial space but does not inherently utilize their feature information. On the other hand, the latter does not consider the spatial relations among pixels. In this paper, a new segmentation algorithm is proposed in which these methods are combined via a notion called membership connectedness. In this algorithm, two kinds of local spatial attractions are considered in the functional form of membership connectedness and the required seeds can be selected automatically. The performance of the proposed method is evaluated using a developed... 

A highly efficient, cost-effective, and durable electrocatalysts based on CoNi metal–organic framework (MOF) nanosheets on highly porous conductive graphene (PCG) is introduced for the hydrogen evolution reaction (HER). The electrocatalyst was fabricated by template-assisted chemical vapor deposition of graphene followed by solvothermal growth of CoNi-MOF nanosheets. Highly porous 3D structure of PCG with open channels of 200–500 nm sizes provided high active surface area and facilitates gas evolution. In a highly alkaline solution, the electrocatalyst exhibits superior figures of merits, e.g. overpotential of 265 mV at −10 mA cm−2 and Tafel slope of 44.5 mV dec-1, to existing hydrogen... 

Comparative studies between response surface methodology (RSM) and artificial neural network (ANN) methods to find the effects of electrospinning parameters on the porosity of nanofiber mats is described. The four important electrospinning parameters studied included solution concentration (wt.%), applied voltage (kV), spinning distance (cm) and volume flow rate (mL/h). It was found that the applied voltage and solution concentration are the two critical parameters affecting the porosity of the nanofiber mats. The two approaches were compared for their modeling and optimization capabilities with the modeling capability of RSM showing superiority over ANN, having comparatively lower values of... 

We present enhanced electrocatalytic activity of three-dimensional graphene scaffolds by decoration with one-dimensional CoxNi1-x MOF nanostructures (0 ≤ x ≤ 1). The decreased overpotential and fast kinetics of the oxygen evolution reaction as compared with the existing materials are shown. The developed bimetallic MOF/3DG composites have great potential to be used in electrocatalytic water oxidation. This journal is © The Royal Society of Chemistry  

Herein, a magnetic zirconium-based metal-organic framework nanocomposite was synthesized by a simple solvothermal method and used as an adsorbent for the removal of direct and acid dyes from aqueous solution. To enhance its adsorption performance, poly(propyleneimine) dendrimer was used to functionalize the as-synthesized magnetic porous nanocomposite. The dendrimer-functionalized magnetic nanocomposite was characterized by field-emission scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, nitrogen adsorption/desorption isotherms, and vibration sample magnetometer. The obtained results revealed the successful synthesis and functionalization of the...