Alakananda Bhattacharya

Hardware Software Partitioning Problem in Embedded System Design Using Particle Swarm Optimization Algorithm

Hardware/software partitioning is a crucial problem in embedded system design. In this paper, we provide an alternative approach to solve this problem using particle swarm optimization (PSO) algorithm. Performance analysis of the proposed scheme with integer linear programming, genetic algorithm and ant colony optimization technique has been compared using standard benchmark datasets, and the computer simulations reveal that the proposed approach outperforms all the meta-heuristic based existing techniques with respect to cumulative runtimes for several runs of the same program. The integer linear programming has been found to yield the optimal solutions, and the proposed swarm scheme yields sub-optimal solution, sufficiently close to the reported results obtained for integer programming.

Abrupt change of dielectric properties in mullite due to titanium and strontium incorporation by sol-gel method

Highly crystallized mullite has been achieved at temperatures of 1100 °C and 1400 °C by sol-gel technique in presence of titanium and strontium ions of different concentrations: G0 = 0 M, G1 = 0.002 M, G2 = 0.01 M, G3 = 0.02 M, G4 = 0.1 M, G5 = 0.2 M and G6 = 0.5 M. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), LCR meter characterized the samples. Mullite formation was found to depend on the concentration of the ions. The dielectric properties (dielectric constant, loss tangent and AC conductivity) of the composites have been measured, and their variation with increasing frequency and concentration of the doped metals was investigated. All the experiments were performed at room temperature. The composites showed maximum dielectric constants of 24.42 and 37.6 at 1400 °C of 0.01 M concentration for titanium and strontium ions at 2 MHz, respectively. Due to the perfect nature of the doped mullite, it can be used for the fabrication of high charge storing capacitors and also as ceramic capacitors in the pico range.

Copper Ion Doped Mullite Composite in Poly (vinylidene Fluoride) Matrix: Effect on Microstructure, Phase Behavior and Electrical Properties

Highly crystallized copper ion doped mullite composites have been synthesized at 1100°C and 1400°C via sol-gel technique with five different strengths of copper ion and was incorporated in poly-vinylidene fluoride (PVDF) to make doped mullite composite/polymer films. We have studied the effects of this dopant on microstructure, phase transformation, and electrical properties of the polymer films over a wide range of frequency from 1.0 KHz to 2.0 MHz. Characterizations were done by various analytical tools at room temperature. Prominent mullite phases were observed from XRD, FTIR spectroscopy and FESEM characterization of composite polymer. The concentration of the dopant and the sintering temperature were found to be the two basic factors which affect the phase transition of the polymer. The composite film showed maximum dielectric constant of 19.96 at 1 KHz for 1.2M concentration of copper ion doped mullite sintered at 1400°C, compared to 3.09 for the pure polymer. Furthermore, both dielectric constant and electrical conductivity of the composite were found to be highly frequency and temperature dependent. After doping, the A.C. conductivity of the composite was found to increase with increasing temperature following Jonscher’s power law and the electrical resistivity reduced too. Moreover, the results revealed that the phase behaviors and micro structural changes of the copper ion doped mullite composite/polymer film affected its electrical properties with possible impact on its applications.

The influence of cobalt acetate on sol-gel derived mullite densification behaviour

Monophasic mullite (3Al2O3·2SiO2) samples doped with 0.002 M, 0.02 M, 0.1 M, 0.15 M and 0.2 M of cobalt were prepared by a sol-gel process. Prepared gels were then dried, grinded, pressed into pellets and sintered at 1 000 °C and 1 300 °C for 4 h. Phase formation and densification behavior has been investigated as a function of the cobalt content and sintering temperature. Mullite densification behavior was analyzed. The density of the sintered ceramics was measured using Archimedes method. CoO and Co related compounds were detected by the analysis for G3, G4 and G5 doping levels. The mullite X-ray diffraction suggests predominant incorporation of Co in the glassy phase, whose quantity increased with the doping level.

Concurrent Resolution in Logic Programming Using Petri Net Models

The paper provides a new approach for automated reasoning in a logic program using extended Petri net models. The design includes extension of classical linear resolution of first order logic clauses by multi-resolution, where a set of clauses can be resolved concurrently without sacrificing any inference, thereby speeding-up the execution of the logic program. The speed-up and utilization rate of resources are used as the performance evaluation metric to compare the performance of the proposed system with the classical one.

Design of a high speed logic engine for distributed decision support systems

The paper provides a new approach to designing a massively parallel logic engine for automated reasoning in a distributed decision support system. The design includes extension of classical linear resolution of first order logic clauses by multi-resolution, where a set of clauses can be resolved concurrently without sacrificing any inference, thereby speeding-up the execution of a logic program. The speed-up and utilization rate of resources are used as the performance evaluation metric to compare the performance of the proposed system with the classical one. A high level logic architecture of the proposed multi-resolution system is presented to explore possible parallelism and pipelining among the tasks, thus determining the execution time of typical logic programs. Possible application of the proposed system in query evaluation of a logic program based database systems is also introduced.