Amit Mishra

Design of Hybrid Fuzzy Neural Network for Function Approximation

In this paper, a hybrid Fuzzy Neural Network (FNN) system for function approximation is presented. The proposed FNN can handle numeric and fuzzy inputs simultaneously. The numeric inputs are fuzzified by input nodes upon presentation to the network while the Fuzzy rule based knowledge is translated directly into network architecture. The connections between input to hidden nodes represent rule antecedents and hidden to output nodes represent rule consequents. All the connections are represented by Gaussian fuzzy sets. The method of activation spread in the network is based on a fuzzy mutual subsethood measure. Rule (hidden) node activations are computed as a fuzzy inner product. For a given numeric o fuzzy input, numeric outputs are computed using volume based defuzzification. A supervised learning procedure based on gradient descent is employed to train the network. The model has been tested on two different approximation problems: sine-cosine function approximation and Narazaki-Ralescu function and shows its natural capability of inference, function approximation, and classification.

OFDM Link with a Better Performance Using Artificial Neural Network

In this paper, a scheme for reducing the peak-to-average power ratio (PAPR) primarily and bit error rate simultaneously in orthogonal frequency division multiplexing using feed forward artificial neural network is proposed and analyzed. The proposed scheme switches one or more null-carriers with data subcarriers to offer minimum PAPR and requires no channel side information during transmission. To reduce high computational complexity, a multilayer neural network with Levenberg–Marquardt training algorithm is used. The proposed scheme thus suits to supplement some of other PAPR-reduction methods with low rate hit and complexity.

AGP---NCS Scheme for PAPR Reduction

In this paper, a combinational method is proposed for peak-to-average power ratio reduction in orthogonal frequency division multiplexing systems using approximate gradient-project with null-subcarriers switching (AGP–NCS) scheme. The key idea of the proposed method is to generate a dynamically extended outer constellation points using AGP method with exploiting the concept of NCS process. The proposed method substantially reduces peak-to-average power without sacrificing the bit error rate. Moreover, proposed scheme requires no channel side information during transmission, therefore shows no reduction in data rate. The simulation results of proposed method show a better performance when compared with other methods.

Enhanced catalytic and antibacterial activity of nanocasted mesoporous silver monoliths: kinetic and thermodynamic studies

Use of low-cost heterogeneous renewable catalysts are essential for effective removal of chemical contaminants like 4-nitrophenol (4-NP) from water bodies. In the present study, for the first time use of surface enhanced (14 m2/g) nanocasted mesoporous silver monolith (AgM) through impregnation into silica monoliths (prepared by sol–gel method) has been demonstrated for its catalytic and antibacterial activity. Highly efficient catalytic reduction rate (2.43 min−1) of 4-NP to 4- aminophenol (4-AP) has been demonstrated using 0.2 gL−1 of AgM catalyst. Enhancement of reduction rate is also observed with increase in temperature (from 25 to 40 °C). Removal of microbial contamination from drinking water is also a prime concern for water purification. Mesoporous AgM shows effective antimicrobial activity against gram negative (E. coli) and gram positive (B. subtilis) bacteria with IC50 values of 75.86 ± 0.173 and 74.56 ± 0.103 respectively at 24 h of incubation.Graphical AbstractUse of low-cost renewable catalysts is essential for effective removal of a chemical contaminant like 4-nitrophenol (4-NP) from water bodies. Nanocasted mesoporous silver monolith (AgM) synthesized via impregnation into silica monoliths (prepared by sol-gel method) has been demonstrated for its catalytic and antibacterial activity. Mesoporous AgM also showed effective antimicrobial activity against gram negative and gram positive bacteria.

An efficient combinational approach for PAPR reduction in MIMO---OFDM system

AbstractThe multiple input multiple output (MIMO) with orthogonal frequency division multiplexing (OFDM) has emerged as a promising solution to enhance the channel capacity and diversity of wireless communication system without any increase in bandwidth. In this paper, a parallel combinational scheme is proposed to reduce peak-to-average power ratio (PAPR) in MIMO–OFDM system under Rayleigh fading environment. The proposed method intelligently incorporates both active gradient project and partial transmit sequence schemes. The results show that the proposed method not only reduces the PAPR and computational complexity of the system but also maintains the bit error rate compared to other schemes.

A sensitive turn on fluorescent probe for detection of biothiols using MnO2@carbon dots nanocomposites

Presently, the combination of carbon quantum dots (CQDs) and metal oxide nanostructures in one frame are being considered for the sensing of purine compounds. In this work, a combined system of CQDs and MnO2 nanostructures was used for the detection of anticancer drugs, 6-Thioguanine (6-TG) and 6-Mercaptopurine (6-MP). The CQDs were synthesized through microwave synthesizer and the MnO2 nanostructures (nanoflowers and nanosheets) were synthesized using facile hydrothermal technique. The CQDs exhibited excellent fluorescence emission at 420nm when excited at 320nm wavelength. By combining CQDs and MnO2 nanostructures, quenching of fluorescence was observed which was attributed to fluorescence resonance energy transfer (FRET) mechanism, where CQDs act as electron donor and MnO2 act as acceptor. This fluorescence quenching behaviour disappeared on the addition of 6-TG and 6-MP due to the formation of Mn-S bond. The detection limit for 6-TG (0.015μM) and 6-MP (0.014μM) was achieved with the linear range of concentration (0-50μM) using both MnO2 nanoflowers and nanosheets. Moreover, the as-prepared fluorescence-sensing technique was successfully employed for the detection of bio-thiol group in enapril drug. Thus a facile, cost-effective and benign chemistry approach for biomolecule detection was designed.

Effect of Surfactants on the Structure and Adsorption Efficiency of Hydroxyapatite Nanorods

Porous hydroxyapatite (HAp) nanorods using surfactant templating proceeded via microwave irradiation method. Study of BET surface area measurement of the HAp nanorods showed that surface area of HAp nanorods with a mixture of cat-anionic surfactants was higher (56.16 m2/g) than their individual counterpart (for anionic 52.8 m2/g and for cationic 48.8 m2/g) as well as without surfactant (19.07 m2/g) due to higher synergistic effect and low critical aggregation concentration of the mixture. Surfactant-directed synthesis of porous HAp has been explored in literature, but the relation between the pore size distribution, surface area and morphology and choice of surfactant(s) was not fully understood and hence in this work we have explored those parameters. The rod shape morphology and the crystal structure of the synthesized HAp nanomaterial were observed by FESEM, HRTEM, and XRD. Due to the higher surface area, HAp nanorods synthesized from the cat-anionic mixture, act as a better adsorbent for dyes and metal ions. The maximum adsorption of dye (methylene blue) was found to be 833.3 mg/g whereas for heavy metal ions like Pb2+ and Cd2+ were 909 and 714.28 mg/g respectively. The kinetic mechanism, the effects of adsorbate pH, temperature, contact time and adsorbent concentration on the dye and metal ions removal were also explored. The antibacterial property of HAp nanorods after doping with silver was investigated against the gram-negative Escherichia coli and gram-positive Bacillus subtilis bacteria by measuring minimal inhibitory concentration (MIC) method.

Green Synthesis of Silver Nanoparticles with Exceptional Colloidal Stability and its Catalytic Activity Toward Nitrophenol Reduction

Silver nanoparticles (Ag NPs) were synthesized by one-step process in the presence of kollicoat as capping, reducing and stabilizing mediator. The synthesized NPs were characterized by using FTIR, TEM, DLS, XRD, EDS and UV-Vis spectroscopy. The resulting Ag NPs had an incomparable colloidal stability against the salt addition and change of pH. The effect of different synthesis parameters and the catalytic property of the NPs were examined.

PAPR Reduction in MIMO-OFDM by Using Active Partial Sequence

Multiple-input multiple-output (MIMO) modeling through the use of orthogonal frequency division multiplexing (OFDM) offers a viable alternative to reduce bandwidth and simultaneously improves the quality of service of wireless mobile communication. One of the major concerns in the MIMO-OFDM system is the high peak-to-average power ratio (PAPR). In this article, a combinational scheme, active partial sequence (APS), is proposed to combat PAPR in MIMO-OFDM under Rayleigh fading environment. The key idea of the APS method is to combine the approximate gradient project followed by partial transmit sequence technique. The simulation results show that the proposed method achieves a significant reduction in PAPR and maintains the same data rate without sacrificing the BER performance over other conventional techniques.

Design of FIR Digital Filters Using ADALINE Neural Network

This paper presents an approach for digital filter design based on single layer feed-forward (ADALINE) neural network. Here the concept of minimization of sum of the square errors between the amplitude response of the desired filter and the filter designed by neural network is used. A couple of examples are simulated and the result of design examples shows that the proposed neural network method is capable of achieving better performance for the filter design.