No-reference image quality assessment using modified extreme learning machine classifier

In this paper, we present a machine learning approach to measure the visual quality of JPEG-coded images. The features for predicting the perceived image quality are extracted by considering key human visual sensitivity (HVS) factors such as edge amplitude, edge length, background activity and background luminance. Image quality assessment involves estimating the functional relationship between HVS features and subjective test scores. The quality of the compressed images are obtained without referring to their original images ('No Reference' metric). Here, the problem of quality estimation is transformed to a classification problem and solved using extreme learning machine (ELM) algorithm. In ELM, the input weights and the bias values are randomly chosen and the output weights are analytically calculated. The generalization performance of the ELM algorithm for classification problems with imbalance in the number of samples per quality class depends critically on the input weights and the bias values. Hence, we propose two schemes, namely the k-fold selection scheme (KS-ELM) and the real-coded genetic algorithm (RCGA-ELM) to select the input weights and the bias values such that the generalization performance of the classifier is a maximum. Results indicate that the proposed schemes significantly improve the performance of ELM classifier under imbalance condition for image quality assessment. The experimental results prove that the estimated visual quality of the proposed RCGA-ELM emulates the mean opinion score very well. The experimental results are compared with the existing JPEG no-reference image quality metric and full-reference structural similarity image quality metric.

Synthesis of Azo Coupled Crown Ethers Containing Transition Metal and other Chromophoric Environments and Their Ion Complexation Properties

The crown ethers, 2,3-benzo-1,4,7,10,13-pentaoxa-cyclopentadeca-2-ene and 2,3, ll,12-dibenzo-l,4,7,10,13,16-hexaoxscyclooctadeca-2,11-diene are incorporated into H,N'-ethylenebis(acetylacetoneimino) nickel(II) and copper(II), phenol, and β-naphthol by diazo coupling reactions. The selective nature of the coupling reaction has-been demonstrated by the isolation of both asymmetric mono- and symmetric bis(glyoxalarylcrownhydrazoneimino) metal(II) complexes. An interesting binuclear complex containing two intramolecularly rearranged (glyoxal-hydrazonearylimino) metal(II) groups joined by 18-crown-6 result8 when bis(arenediazonium)-18-crown-6 is coupled with the metal(I1) Schiff bases. The substituted ethers form cationic salts with NaClO4, KCNS, NH4CNS, 14g(CNS)2 and Ca(CNS)2. All the synthesised ethers exhibit ion selectivity sequence as K+ > Na+ and Ca2+ > Mg2+.

Synthesis of Azo Coupled Crown Ethers Containing Transition Metal and other Chromophoric Environments and Their Ion Complexation Properties

The crown ethers, 2,3-benzo-1,4,7,10,13-pentaoxa-cyclopentadeca-2-ene and 2,3, ll,12-dibenzo-l,4,7,10,13,16-hexaoxscyclooctadeca-2,11-diene are incorporated into H,N'-ethylenebis(acetylacetoneimino) nickel(II) and copper(II), phenol, and β-naphthol by diazo coupling reactions. The selective nature of the coupling reaction has-been demonstrated by the isolation of both asymmetric mono- and symmetric bis(glyoxalarylcrownhydrazoneimino) metal(II) complexes. An interesting binuclear complex containing two intramolecularly rearranged (glyoxal-hydrazonearylimino) metal(II) groups joined by 18-crown-6 result8 when bis(arenediazonium)-18-crown-6 is coupled with the metal(I1) Schiff bases. The substituted ethers form cationic salts with NaClO4, KCNS, NH4CNS, 14g(CNS)2 and Ca(CNS)2. All the synthesised ethers exhibit ion selectivity sequence as K+ > Na+ and Ca2+ > Mg2+.

The Consequences of Phenotypic Plasticity in Cyclically Varying Environments: A Genetic Algorithm Study

By “phenotypic plasticity” we refer to the capacity of a genotype to exhibit different phenotypes, whether in the same or in different environments. We have previously demonstrated that phenotypic plasticity can improve the degree of adaptation achieved via natural selection (Behera & Nanjundiah, 1995). That result was obtained from a genetic algorithm model of haploid genotypes (idealized as one-dimensional strings of genes) evolving in a fixed environment. Here, the dynamics of evolution is examined under conditions of a cyclically varying environment. We find that the rate of evolution, as well as the extent of adaptation (as measured by mean population fitness) is lowered because of environmental cycling. The decrease is adaptation caused by a varying environment can, however, be partly or wholly compensated by an increase in the degree of plasticity that a genotype is capable of. Also, the reduction of population fitness caused by a variable environment can be partially offset by decreasing the total number of genetic loci. We conjecture that an increase in genome size may have been among the factors responsible for the evolution of phenotypic plasticity.

The effect of horizontal resolution on simulation of very extreme US precipitation events in a global atmosphere model

We investigate the ability of a global atmospheric general circulation model (AGCM) to reproduce observed 20 year return values of the annual maximum daily precipitation totals over the continental United States as a function of horizontal resolution. We find that at the high resolutions enabled by contemporary supercomputers, the AGCM can produce values of comparable magnitude to high quality observations. However, at the resolutions typical of the coupled general circulation models used in the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, the precipitation return values are severely underestimated.

On the roles of the northeast cold surge, the Borneo vortex, the Madden-Julian Oscillation, and the Indian Ocean Dipole during the extreme 2006/2007 flood in southern Peninsular Malaysia

The mid-December 2006 to late January 2007 flood in southern Peninsular Malaysia was the worst flood in a century and was caused by three extreme precipitation episodes. These extreme precipitation events were mainly associated with strong northeasterly winds over the South China Sea. In all cases, the northeasterlies penetrated anomalously far south and followed almost a straight trajectory. The elevated terrain over Sumatra and southern Peninsular Malaysia caused low-level convergence. The strong easterly winds near Java associated with the Rossby wave-type response to Madden-Julian Oscillation (MJO) inhibited the counter-clockwise turning of the northeasterlies and the formation of the Borneo vortex, which, in turn, enhanced the low-level convergence over the region. The abrupt termination of the Indian Ocean Dipole (IOD) in December 2006 played a secondary role as warmer equatorial Indian Ocean helped in the MJO formation.

The Critical Role of N- and C-Terminal Contact in Protein Stability and Folding of a Family 10 Xylanase under Extreme Conditions

Background: Stabilization strategies adopted by proteins under extreme conditions are very complex and involve various kinds of interactions. Recent studies have shown that a large proportion of proteins have their N- and C-terminal elements in close contact and suggested they play a role in protein folding and stability. However, the biological significance of this contact remains elusive. Methodology: In the present study, we investigate the role of N- and C-terminal residue interaction using a family 10 xylanase (BSX) with a TIM-barrel structure that shows stability under high temperature,alkali pH, and protease and SDS treatment. Based on crystal structure,an aromatic cluster was identified that involves Phe4, Trp6 and Tyr343 holding the Nand C-terminus together; this is a unique and important feature of this protein that might be crucial for folding and stabilityunder poly-extreme conditions. Conclusion: A series of mutants was created to disrupt this aromatic cluster formation and study the loss of stability and function under given conditions. While the deletions of Phe4 resulted in loss of stability, removal of Trp6 and Tyr343 affected in vivo folding and activity. Alanine substitution with Phe4, Trp6 and Tyr343 drastically decreased stability under all parameters studied. Importantly,substitution of Phe4 with Trp increased stability in SDS treatment.Mass spectrometry results of limited proteolysis further demonstrated that the Arg344 residue is highly susceptible to trypsin digestion in sensitive mutants such as DF4, W6A and Y343A, suggesting again that disruption of the Phe4-Trp6-Tyr343 (F-W-Y) cluster destabilizes the N-and C-terminal interaction. Our results underscore the importance of N- and C-terminal contact through aromatic interactions in protein folding and stability under extreme conditions, and these results may be useful to improve the stability of other proteins under suboptimal conditions.

Reliability models for existing structures based on dynamic state estimation and data based asymptotic extreme value analysis

The problem of time variant reliability analysis of existing structures subjected to stationary random dynamic excitations is considered. The study assumes that samples of dynamic response of the structure, under the action of external excitations, have been measured at a set of sparse points on the structure. The utilization of these measurements m in updating reliability models, postulated prior to making any measurements, is considered. This is achieved by using dynamic state estimation methods which combine results from Markov process theory and Bayes' theorem. The uncertainties present in measurements as well as in the postulated model for the structural behaviour are accounted for. The samples of external excitations are taken to emanate from known stochastic models and allowance is made for ability (or lack of it) to measure the applied excitations. The future reliability of the structure is modeled using expected structural response conditioned on all the measurements made. This expected response is shown to have a time varying mean and a random component that can be treated as being weakly stationary. For linear systems, an approximate analytical solution for the problem of reliability model updating is obtained by combining theories of discrete Kalman filter and level crossing statistics. For the case of nonlinear systems, the problem is tackled by combining particle filtering strategies with data based extreme value analysis. In all these studies, the governing stochastic differential equations are discretized using the strong forms of Ito-Taylor's discretization schemes. The possibility of using conditional simulation strategies, when applied external actions are measured, is also considered. The proposed procedures are exemplifiedmby considering the reliability analysis of a few low-dimensional dynamical systems based on synthetically generated measurement data. The performance of the procedures developed is also assessed based on a limited amount of pertinent Monte Carlo simulations. (C) 2010 Elsevier Ltd. All rights reserved.

Advances in the analysis and design of concrete structures, metal containments and liner plate for extreme loads

The material presented in this paper summarizes the progress that has been made in the analysis, design, and testing of concrete structures. The material is summarized in the following documents: 1. Part I - Containment Design Criteria and Loading Combinations - J.D. Stevenson (Stevenson and Associates, Cleveland, Ohio, USA) 2. Part II - Reinforced and Prestressed Concrete Behavior - J. Eibl and M. Curbach (Karlsruhe University, Karlsruhe, Germany) 3. Part III - Concrete Containment Analysis, Design and Related Testing - T.E. Johnson and M.A. Daye (Bechtel Power Corporation, Gaithersburg, Maryland USA) 4. Part IV - Impact and Impulse Loading and Response Prediction - J.D. Riera (School of Engineering - UFRGS, Porto Alegre, RS, Brazil) 5. Part V - Metal Containments and Liner Plate Systems - N.J. Krutzik (Siemens AG, Offenbach Am Main, Germany) 6. Part VI - Prestressed Reactor Vessel Design, Testing and Analysis - J. Nemet (Austrian Research Center, Seibersdorf, Austria) and K.T.S. Iyengar (Indian Institute of Science, Bangalore, India).

Frontier Based Multiple Goal Search in Unknown Environments

We present a frontier based algorithm for searching multiple goals in a fully unknown environment, with only information about the regions where the goals are most likely to be located. Our algorithm chooses an ``active goal'' from the ``active goal list'' generated by running a Traveling Salesman Problem (Tsp) routine with the given centroid locations of the goal regions. We use the concept of ``goal switching'' which helps not only in reaching more number of goals in given time, but also prevents unnecessary search around the goals that are not accessible (surrounded by walls). The simulation study shows that our algorithm outperforms Multi-Heuristic LRTA* (MELRTA*) which is a significant representative of multiple goal search approaches in an unknown environment, especially in environments with wall like obstacles.

Goal Seeking for Robots in Unknown Environments

We consider the problem of goal seeking by robots in unknown environments. We present a frontier based algorithm for finding a route to a goal in a fully unknown environment, where information about the goal region (GR), the region where the goal is most likely to be located, is available. Our algorithm efficiently chooses the best candidate frontier cell, which is on the boundary between explored space and unexplored space, having the maximum ``goal seeking index'', to reach the goal in minimal number of moves. Modification of the algorithm is also proposed to further reduce the number of moves toward the goal. The algorithm has been tested extensively in simulation runs and results demonstrate that the algorithm effectively directs the robot to the goal and completes the search task in minimal number of moves in bounded as well as unbounded environments. The algorithm is shown to perform as well as a state of the art agent centered search algorithm RTAA*, in cluttered environments if exact location of the goal is known at the beginning of the mission and is shown to perform better in uncluttered environments.

Deformation behaviour of commercially pure titanium at extreme strain rates

The evolution of microstructure and texture during room temperature compression of commercially pure Ti with four different initial orientations were studied under quasi-static and dynamic loading conditions. At a low strain rate (epsilon)over dot = 3 x 10(-4) s(-1) the different initial textures yielded the same end texture, despite different microstructural evolution in terms of twin boundaries. High strain rate deformation at (epsilon)over dot = 1.5 x 10(3) s(-1) was characterized by extensive twinning and evolution of a texture that was similar to that at low strain rate with minor differences. However, there was a significant difference in the strength of the texture for different orientations that was absent for low strain rate deformed samples at high strain rate. A viscoplastic self-consistent model with a secant approach was used to corroborate the experimental results by simulation. (C) 2011 Published by Elsevier Ltd. on behalf of Acta Materialia Inc.