Exploiting Device Mismatch in Neuromorphic VLSI Systems to Implement Axonal Delays

Sheik S, Chicca E, Indiveri G. Exploiting Device Mismatch in Neuromorphic VLSI Systems to Implement Axonal Delays. Presented at the International Joint Conference on Neural Networks (IJCNN), Brisbane, Australia.Axonal delays are used in neural computation to implement faithful models of biological neural systems, and in spiking neural networks models to solve computationally demanding tasks. While there is an increasing number of software simulations of spiking neural networks that make use of axonal delays, only a small fraction of currently existing hardware neuromorphic systems supports them. In this paper we demonstrate a strategy to implement temporal delays in hardware spiking neural networks distributed across multiple Very Large Scale Integration (VLSI) chips. This is achieved by exploiting the inherent device mismatch present in the analog circuits that implement silicon neurons and synapses inside the chips, and the digital communication infrastructure used to configure the network topology and transmit the spikes across chips. We present an example of a recurrent VLSI spiking neural network that employs axonal delays and demonstrate how the proposed strategy efficiently implements them in hardware

Oxidation of aliphatic alcohols by triethylammonium chlorochromate in non-aqueous medium – A kinetic and mechanistic study

AbstractThe oxidation of some aliphatic alcohols by triethylammonium chlorochromate (TriEACC) in dimethyl sulfoxide leads to the formation of the corresponding carbonyl compounds. The reaction is first order with respect to TriEACC. The reaction exhibited Michaelis–Menten type kinetics with respect to alcohol. The reaction is catalyzed by hydrogen ions. The hydrogen-ion dependence has the form: kobs=a+b[H+]. The oxidation of [1,1-2H2] ethanol (MeCD2OH) exhibits a substantial primary kinetic isotope effect. Oxidation of aliphatic alcohol was studied in 19 different organic solvents. The solvent effect has been analysed using Kamlet’s and Swain’s multi-parametric equation. A suitable mechanism has been proposed

A Study of Affordable Roofing Systems with Composite Slab

Affordable housing is a term used to describe dwelling units whose total housing cost are deemed affordable to a group of people within a specified income range. Structural roofing system contribute substantially to cost of construction of housing unit in normal situation, hence any savings attained in roofing system will reduce the cost of construction of housing unit. In the study undertaken, the roofing system consists of primary beams and secondary beams perpendicular to each other. The infill proposed is a composite slab panel consisting of decking sheets, galvanized iron(G.I) sheets of trapezoidal and corrugated cross section at bottom with a layer of concrete above it. The rectangular composite panelsconsidered in the study have a least width of 0.5m and 0.75m with an aspect ratio varying from 1.00 to 2.00. The rectangular composite panels are designed using M20 grade concrete and reinforcing steel of yield strength 415 N/mm2. The cost analysis is made for the roofing system and the proposed roofing system indicates a cost reduction 40% when compared to a conventional reinforced concrete (RCC) slab of same size. The weight of the beam systems and the panels are found to be relatively less and can handled easily by two to five masons thus reducing the labour cost. The beam systems and panels are precasted and can be easily placed thus eliminating need of shuttering, leading to faster construction of slab. The proposed roofing system is cost effective with a greater speed of construction compared to conventional roofing system

Linear Antenna Array Synthesis for Unconstrained and Constrained Nulls Using Social Group Optimization Algorithm

601-603In wireless communications, the radiating system is required to produce radiation patterns which are entirely described by nulls along with some constraints like side lobe level. With the latest developments in the wireless communication systems, the Linear Array Antenna (LAA) design emerged challenge to the antenna engineers. In this paper, the LAA synthesis is performed using novel Social Group Optimization Algorithm (SGOA). The synthesis technique employs non-uniform amplitude distribution. The array synthesis problem is transformed into an optimization problem with number of elements as the dimension of the problem. Obtaining desired nulls in the radiation pattern without and with constraint of Side Lobe Level (SLL) is the objective of the work. Results pertaining to single and multiple nulls for both the above cases are presented. The novel evolutionary computing named as SGOA efficiently achieved the above objectives with an LAA of 12 elements

Experimental Study on Fractional Replacement of Cement with Waste Paper Pulp in Concrete

This study is about waste paper pulp from paper industries to be employed as a fractional substitution of cement in concrete at varying percentages to access its properties and performance. To evaluate the fresh property of concrete, slump cone test was conducted. The concrete compressive strength test (CST) was evaluated by testing 36 cubes of side 150mm. Twelve concrete cylinder specimens of ‘diameter 150mm and height 300mm’ were cast to evaluate the split tensile strength (STS) and twelve specimens of size ‘150mm x 150mm x 700mm’ were cast to find out the modulus of rupture (MOR) of concrete. The slump value showed an indirect correlation with the increment in the percentage of waste paper pulp.  The 28th day strength tests revealed that the compressive strength was increased by 15.5% for a 10% substitution of cement. The compressive strength was nearly the same for 5% substitution and there was a fall in compressive strength by 16.67% for 15% substitution. The tensile strength was increased by a maximum of 7.5% for 5% substitution of cement and it decreased progressively after 10% substitution. Flexural strength was increased by about 10.89% for 5% substitution, 2.5% for 10% substitution and a decrease in flexural strength of about 13.9% for 15% substitution was observed. Thus, it was concluded that fractional substitution of cement by waste paper pulp can be achieved by 5% for optimum results. The 5% substitution of cement may yield an economic and environment-friendly concrete construction

Melamine trisulfonic acid as an efficient catalyst for the synthesis of 2,6-dimethyl-4-substituted-1,4-dihydropyridine-3,5-diethyl/dimethylcarboxylate derivatives via Hantzsch reaction in solvent free condition

AbstractA facile and highly efficient one-pot synthesis of 1,4-dihydropyridine derivatives (1,4-DHPs) is reported via three component condensation reaction of aldehydes, ethyl acetoacetate or methyl acetoacetate and ammonium acetate using environmentally benign melamine trisulfonic acid (MTSA) as a catalyst in solvent free condition at 60°C. The method presented here is applied to the tenets of green chemistry to the generation of biologically interesting products under solvent-free media that is less expensive and less toxic than those with organic solvents. Also, the catalyst is recyclable and could be reused without significant loss of activity. Even after three runs for the reaction, the catalytic activity of MTSA was almost the same as that of the freshly used catalyst.The method also offers several advantages including high yields and simple work-up procedure

PLANT MEDIATED SYNTHESIS AND CHARACTERIZATION OF SILVER NANOPARTICLES

Objective: The study was aimed to synthesis and characterization of silver nanoparticles from five different herbal plants (Terminalia chebula, Mimusops elengi, Myristica fragrans, Centella asiatica and Hemidesmus indicus). Methods: The qualitative analysis of plant extracts was performed to determine the presence of secondary metabolites. The plant mediated silver nanoparticles were synthesized. The color changed into brown to black color indicating the formation of AgNPs. The characterization of synthesized AgNPs was carried out by different methods such as UV-Vis Spectra, FE-TEM, Particle size analysis, Zeta potential analysis, XRD and FTIR. The antimicrobial activity of synthesized silver nanoparticles also examined against three fungi and bacteria. Results: The UV wave length of AgNPs is from 300 to 450 nm. The average size of AgNPs 581 d.nm, zeta potential is -13.3 mV. The FTIR results show that AgNPs contains the functional groups. In antimicrobial activity of all AgNPs synthesized by five plants inhibits the growth of bacteria and Terminalia chebula showed maximum effect. The XRD pattern clearly confirmed that the synthesized silver nanoparticles are crystalline in nature. TEM results shows that synthesized silver nanoparticles are round in shape. Conclusion: The green synthesis of nanoparticles shows that cost-effective, environmentally friendly, and safe for human therapeutic use. Color change, UV-Vis spectra, TEM and XRD analysis confirmed the stability of synthesized AgNPs. Â&nbsp