The Analysis of Variance.

African vultures optimization algorithm: A new nature-inspired metaheuristic algorithm for global optimization problems

Metaheuristics play a critical role in solving optimization problems, and most of them have been inspired by the collective intelligence of natural organisms in nature. This paper proposes a new metaheuristic algorithm inspired by gorilla troops' social intelligence in nature, called Artificial Gorilla Troops Optimizer (GTO). In this algorithm, gorillas' collective life is mathematically formulated, and new mechanisms are designed to perform exploration and exploitation. To evaluate the GTO, we apply it to 52 standard benchmark functions and seven engineering problems. Friedman's test and Wilcoxon rank-sum statistical tests statistically compared the proposed method with several existing metaheuristics. The results demonstrate that the GTO performs better than comparative algorithms on most benchmark functions, particularly on high-dimensional problems. The results demonstrate that the GTO can provide superior results compared with other metaheuristics.

Artificial gorilla troops optimizer: A new nature-inspired metaheuristic algorithm for global optimization problems

Design of inferential sensors in the process industry: A review of Bayesian methods

On the Theory of Optimal Sensor Placement

An optimal sensor placement is defined as a sensor configuration that achieves the minimum capital cost while observing prespecified performance criteria. Previous formulations of this problem have resulted in the definition of a mixed-integer nonlinear program (MINLP) with dimensions dependent on the value of the integer decision variables. The main contribution of this work is an equivalent reformulation of the design problem such that the dimension of the NLP is independent of all decision variables. Additionally, the traditional sensor-placement problem, based on static process conditions, is extended to linear dynamic processes. The final contribution is the exact conversion of the general NLP into a convex program through the use of linear matrix inequalities. The aggregation of these results show that the sensor-placement problem can be solved globally and eficiently using standard interior-point and branch-and-bound search algorithms.

On the theory of optimal sensor placement

Optimizing properties of nanoclay–nitrile rubber (NBR) composites using Face Centred Central Composite Design

A computationally fast technique accurately estimates process variables when conditions are dynamic due to changes in steady states. The process variable estimators are unbiased and have known distributions. Thus, confidence intervals for true values of process variables are provided. The formulation of this technique was motivated by a recursive, dynamic data reconciliation technique that obtains very accurate estimators. These two techniques are compared in terms of computational speed and accuracy of estimators. The proposed technique is computationally faster, but not as accurate when variances of process measurements are large. However, the accuracy of the proposed estimators is shown to approach that of the recursive technique by iteratively recalculating estimates and when measurement variances decrease.

Unbiased estimation in dynamic data reconciliation

Intelligent selection of hypothesis tests to enhance gross error identification

Cactus-like hierarchical rutile TiO2 flowers and three dimensional (3D) highly branched rutile TiO2 nanorods with sizes measuring up to 5 microns were synthesized on conductive substrates by a facile hydrothermal route without the presence of a surfactant or template. These samples with different morphologies and microstructures were studied by X-ray powder diffraction (XRD), field emission-scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM). We also studied the photovoltaic performances of these samples by using them as photoanodes in dye-sensitized solar cells (DSSCs). The highly branched TiO2 nanorod based photoanode in DSSCs showed a power conversion efficiency of 3.07% which was significantly higher than that of the cactus TiO2 flower based (2.66%) photoanode. The electrochemical impedance spectroscopy (EIS) analysis of the interfacial charge transfer kinetics in these photoanodes in DSSCs showed higher recombination resistance (R2) and longer electron lifetime in highly branched nanorods. The enhancement of the efficiency of the highly branched TiO2 nanorod photoanode based DSSC compared to that of cactus TiO2 flower DSSC is mainly attributed to the superior light scattering capability, fast electron transfer and longer electron lifetime with suppressed recombination.

Synthesis of micrometer-sized hierarchical rutile TiO2 flowers and their application in dye sensitized solar cells

The electrical conductivity and yield of polyaniline (PANi) were optimized using a design of experiments (DOE). PANi samples were synthesized by the chemical oxidative polymerization of aniline using methane sulfonic acid as the dopant acid and ammonium persulfate as the oxidant. The main factors in the synthesis of PANi that can affect the conductivity were identified as (i) the concentration of dopant acid, (ii) oxidant-to-monomer ratio, and (iii) the addition rate of oxidant to monomer. Using a Box-Behnken DOE method the regression equation, main effects plots, contour plots, and optimization plots for conductivity and yield were generated and analyzed. Under the optimized conditions of dopant acid concentration of 0.9M, an oxidant addition rate of 30 mL/h and an OM ratio of 0.9, PANi with a conductivity of 1.95 S/cm and yield of 95% was obtained. The observed trends in the four-point probe conductivity measurements were correlated with the polymer structure using fourier transform infrared spectroscopy, X-ray diffraction studies, and scanning electron microscopy. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1047-1057, 2013

Sriram Devanathan

Papers

Optimizing properties of nanoclay–nitrile rubber (NBR) composites using Face Centred Central Composite Design

Unbiased estimation in dynamic data reconciliation

Intelligent selection of hypothesis tests to enhance gross error identification

Synthesis of micrometer-sized hierarchical rutile TiO2 flowers and their application in dye sensitized solar cells

Optimization of the conductivity and yield of chemically synthesized polyaniline using a design of experiments