New acceleration technique for the backpropagation algorithm

Artificial neural networks have been studied for many years in the hope of achieving human like performance in the area of pattern recognition, speech synthesis and higher level of cognitive process. In the connectionist model there are several interconnected processing elements called the neurons that have limited processing capability. Even though the rate of information transmitted between these elements is limited, the complex interconnection and the cooperative interaction between these elements results in a vastly increased computing power; The neural network models are specified by an organized network topology of interconnected neurons. These networks have to be trained in order them to be used for a specific purpose. Backpropagation is one of the popular methods of training the neural networks. There has been a lot of improvement over the speed of convergence of standard backpropagation algorithm in the recent past. Herein we have presented a new technique for accelerating the existing backpropagation without modifying it. We have used the fourth order interpolation method for the dominant eigen values, by using these we change the slope of the activation function. And by doing so we increase the speed of convergence of the backpropagation algorithm; Our experiments have shown significant improvement in the convergence time for problems widely used in benchmarKing Three to ten fold decrease in convergence time is achieved. Convergence time decreases as the complexity of the problem increases. The technique adjusts the energy state of the system so as to escape from local minima

Synthesis, Characterization and Visible Light Driven Photocatalytic Applications of Bi2WO6 Nanoparticles Towards Congo Red Dye Degradation

Bi2WO6 nanoparticles were synthesized using two novel methods namely amorphous citrate method and urea hydrolysis method. Phase pure Bi2WO6 was obtained in amorphous citrate method which have been ascribe to the homogeneous distribution of metal ions in the precursor due to the inherent ligating capacity of citric acid. The Bi2WO6 synthesized by urea hydrolysis method contain a mixed phase system with Bi2WO6 as major and Bi2W2O9 as minor phase. UV-visible spectral study indicated that the Bi2WO6 material exhibit significant visible light absorption suitable for photocatalytic applications. The BWO material exhibit quantum confinement effect as manifested from the higher band gap value of ~2.9 eV observed. The particle size of the BWO-AC quantum dots are found to be in the range of 6-8 nm from TEM study. The BWO material synthesized by both methods display promising photocatalytic activity for degradation of congored from aqueous sources under visible light irradiation

Reduction of Energy Consumption and Latency in Cognitive WBAN Using LDPC Error Corrcting Codes

Wireless body area network has been implemented to monitor the human body systems to detect and cure the diseases. Lifetime and Latency are the major concerns in for Wireless body area network. Due to the signal transmission takes place in or around the body in WBAN, Packet Error Rate has been affected because of channel fading and collisions in the channel due to the existence of other wireless devices. Therefore, latency and lifetime of the sensors very crucial. To reduce these issues, cognitive radio (CR) armed Wireless body area network should be a better option. Here, Reed Solomon and LDPC error correcting mechanism for CR-armed Wireless body area network has been proposed. Various issues in Cognitive Radio networks have been investigated till date to cope with latency and energy utilization. Error control techniques have not explored for Cognitive Radio networks and the existing error correcting mechanism for WSNs should not be imposed to Cognitive Radio network due to the mechanism of adaptive spectrum access mechanism. The method proposed here selects the routes and number of hops from source to sink adaptively and alters the redundancy to reduce the expected energy and latency utilization. The simulation results show that the proposed mechanism gives better results with the view of energy, latency consumption in the multihop CR armed Wireless body area network

NON-CHROMATOGRAPHIC PURIFICATION OF SYNTHETIC BIO-OLIGOMERS

Synthetic oligonucleotides and peptides have found wide applications in industry and academic research labs. There are ~60 peptide drugs on the market and over 500 under development. The global annual sale of peptide drugs in 2010 was estimated to be $13 billion. There are three oligonucleotide-based drugs on market; among them, the FDA newly approved Kynamro was predicted to have a$100 million annual sale. The annual sale of oligonucleotides to academic labs was estimated to be $700 million. Both bio-oligomers are mostly synthesized on automated synthesizers using solid phase synthesis technology, in which nucleoside or amino acid monomers are added sequentially until the desired full-length sequence is reached. The additions cannot be complete, which generates truncated undesired failure sequences. For almost all applications, these impurities must be removed. The most widely used method is HPLC. However, the method is slow, expensive, labor-intensive, not amendable for automation, difficult to scale up, and unsuitable for high throughput purification. It needs large capital investment, and consumes large volumes of harmful solvents. The purification costs are estimated to be more than 50% of total production costs. Other methods for bio-oligomer purification also have drawbacks, and are less favored than HPLC for most applications. To overcome the problems of known biopolymer purification technologies, we have developed two non-chromatographic purification methods. They are (1) catching failure sequences by polymerization, and (2) catching full-length sequences by polymerization. In the first method, a polymerizable group is attached to the failure sequences of the bio-oligomers during automated synthesis; purification is achieved by simply polymerizing the failure sequences into an insoluble gel and extracting full-length sequences. In the second method, a polymerizable group is attached to the full-length sequences, which are then incorporated into a polymer; impurities are removed by washing, and pure product is cleaved from polymer. These methods do not need chromatography, and all drawbacks of HPLC no longer exist. Using them, purification is achieved by simple manipulations such as shaking and extraction. Therefore, they are suitable for large scale purification of oligonucleotide and peptide drugs, and also ideal for high throughput purification, which currently has a high demand for research projects involving total gene synthesis. The dissertation will present the details about the development of the techniques. Chapter 1 will make an introduction to oligodeoxynucleotides (ODNs), their synthesis and purification. Chapter 2 will describe the detailed studies of using the catching failure sequences by polymerization method to purify ODNs. Chapter 3 will describe the further optimization of the catching failure sequences by polymerization ODN purification technology to the level of practical use. Chapter 4 will present using the catching full-length sequence by polymerization method for ODN purification using acid-cleavable linker. Chapter 5 will make an introduction to peptides, their synthesis and purification. Chapter 6 will describe the studies using the catching full-length sequence by polymerization method for peptide purification

Morphological Study of Voids in Ultra-Large Models of Amorphous Silicon

The microstructure of voids in pure and hydrogen-rich amorphous silicon (a:Si) network was studied in ultra-large models of amorphous silicon, using classical and quantum- mechanical simulations, on the nanometer length scale. The nanostructure, particularly voids of device grade ultra-large models of a:Si was studied, in which observed three-dimensional realistic voids were extended using geometrical approach within the experimental limit of void-volume fractions. In device-grade simulated models, the effect of void morphology; size, shape, number density, and distribution on simulated scattering intensities in small- angle region were investigated. The evolution of voids on annealing below the crystallization temperature (≤ 800 K) was examined, where the extent of the void reconstruction was reported by using high-quality three-dimensional rendering software and calculating an average size and volume of the voids. Additionally, the role of bonded and non-bonded hydrogens near the vicinity of the void’s wall in a:Si network was observed. Our simulated results suggested that, in extended void structures, X-ray scattering intensities in the small- angle region were sensitive to the number density, size, shape and the distribution of the voids in unequal strength. In both classical and local ab initio molecular dynamics models of a:Si, the reconstruction of the voids were observed but in later models, with and without present hydrogen reconstruction effect was observed greater. The distribution and dynamics of bonded and non-bonded hydrogen in heavily hydrogenated (≥ 14 at.%) ultra-large models of a:Si suggested that, void’s wall were decorated with more silicon dihydride (SiH2) bonds and 9-13% of the total H were realized as molecular hydrogen (H2) respectively from 300 K- 800 K annealing temperature. This work suggested that, a:Si sample with≥14 at.% H and ≤ 0.2% volume-fraction of voids, may be appropriate for interface hydrogenated amorphous silicon/crystalline silicon (a:Si:H/c-Si) material used in heterojunction silicon solar cell to obtain the better-passivated surface due to the presence of mobile non-bonded hydrogens