A hybrid list-based task scheduling scheme for heterogeneous computing

The Journal of Supercomputing - Efficient task scheduling is required to attain high performance in both homogeneous and heterogeneous computing systems. An application can be considered as a task...     

Multi-view document clustering via ensemble method

Multi-view clustering has become an important extension of ensemble clustering. In multi-view clustering, we apply clustering algorithms on different views of the data to obtain different cluster labels for the same set of objects. These results are then combined in such a manner that the final clustering gives better result than individual clustering of each multi-view data. Multi view clustering can be applied at various stages of the clustering paradigm. This paper proposes a novel multi-view clustering algorithm that combines different ensemble techniques. Our approach is based on computing different similarity matrices on the individual datasets and aggregates these to form a combined similarity matrix, which is then used to obtain the final clustering. We tested our approach on several datasets and perform a comparison with other state-of-the-art algorithms. Our results show that the proposed algorithm outperforms several other methods in terms of accuracy while maintaining the overall complexity of the individual approaches.     

Characterization of soluble organic matter from Youssoufia rock phosphate

Extractable lipids represent 12% of the total organic matter contained in Youssoufla rock phosphate. This soluble organic matter corresponds mainly to free, directly extractable lipids. They are dominantly neutral lipids (neutral/acid fraction ratio: 1.5). Gas chromatographic-mass spectrometric studies showed for the alkanes a bimodal distribution C₁₅---C₂₁ and C₂₂---C₃₃ dominated, respectively, by C₁₈ and C₂₇. The dominant hopanes were identified under the thermodynamically stable αβ-form, αββ-steranes were also present with the non-diagenetic ααα- and βαα-steranes. Phytane and pristane deriving from the transformation of chlorophyll chains were also identified.Acids were saturated linear C₁₂---C₃₀ acids with a predominance of the C₁₆ and C₁₈ members, unsaturated C_16:1 and C_18:1 acids and even dicarboxylic acids. The results obtained suggest that the organic matter present in the phosphate has a marine origin with a significant continental contribution.     

Effect of organomodified clay on the reaction kinetics,properties and thermal degradation of nanocomposites based on poly(styrene‐co‐ethyl methacrylate)

In this research, synthesis of novel nanocomposites based on a poly(styrene‐co‐ethyl methacrylate) copolymer matrix was investigated with different types and amounts of organomodified montmorillonite (MMT) clays. The in situ polymerization technique was selected with dispersion of the MMT nanoparticles into the comonomer mixture and subsequent bulk radical polymerization. Reaction kinetics was measured gravimetrically and it was found that the existence of rigid phenyl rings in the organomodifier may result in a hindered reaction rate especially at high clay loadings. Structural characteristics of the nanocomposites formed were verified with XRD and Fourier transform infrared analysis and mainly intercalated/partially exfoliated structures were verified; their glass transition temperature was measured with DSC, and their molecular weight distribution and average molecular weights were measured with gel permeation chromatography. The latter was also used to measure the variation of the copolymer average molecular weight with conversion. Slightly higher average molecular weight and T_g values for the copolymer in the nanocomposites were measured, compared with neat copolymer. The thermal stability of the nanocomposites was measured with TGA and found to be significantly improved. One‐step degradation revealed the existence of macromolecular chains without defective structures. Finally, pyrolysis of the nanocomposite copolymers resulted in the production of both comonomers in high amounts, followed by some dimers or trimers. © 2013 Society of Chemical Industry     

The thermal effect on vibration of zigzag single walled carbon nanotubes using nonlocal Timoshenko beam theory

Based on nonlocal theory of thermal elasticity mechanics, a nonlocal elastic Timoshenko beam model is developed for free vibration analysis of zigzag single-walled carbon nanotube (SWCNT) considering thermal effect. The nonlocal constitutive equations of Eringen are used in the formulations. The equivalent Young’s modulus and shear modulus for zigzag SWCNT are derived using an energy-equivalent model. Results indicate significant dependence of natural frequencies on the temperature change as well as the chirality of zigzag carbon nanotube. These findings are important in mechanical design considerations of devices that use carbon nanotubes.     

A Numerical structural approach to surge detection and isolation in compression systems using fuzzy logic controller

Fuzzy control is a practical alternative for a variety of challenging control applications since it provides a convenient method for constructing nonlinear controllers via the use of heuristic information. This approach provides a formal methodology for representing, manipulating, and implementing a human’s heuristic knowledge about how to modeled and to control a system. This paper focuses on the application of fuzzy control approach to the surge phenomena in centrifugal compression system. Fuzzy controller is designed to consist of an active surge control and phase control without any explicit system models, but driven in the human thinking mechanism. This fuzzy control methodology suggested in this work reproduced well the main characteristics of the turbo compressor dynamic model developed by Moore and Gretzer and give place to a more precise and easy to handle representation. Application and simulation results are performed to demonstrate the effectiveness of this controller. Studies show that, the proposed controller provides good tracking control performance for the compression system at different operating conditions and moreover improves the dynamic performances of the system.     

Modeling and prediction of Turkey’s electricity consumption using Artificial Neural Networks

Artificial Neural Networks are proposed to model and predict electricity consumption of Turkey. Multi layer perceptron with backpropagation training algorithm is used as the neural network topology. Tangent-sigmoid and pure-linear transfer functions are selected in the hidden and output layer processing elements, respectively. These input–output network models are a result of relationships that exist among electricity consumption and several other socioeconomic variables. Electricity consumption is modeled as a function of economic indicators such as population, gross national product, imports and exports. It is also modeled using export–import ratio and time input only. Performance comparison among different models is made based on absolute and percentage mean square error. Electricity consumption of Turkey is predicted until 2027 using data from 1975 to 2006 along with other economic indicators. The results show that electricity consumption can be modeled using Artificial Neural Networks, and the models can be used to predict future electricity consumption.     

A Comparative Study of Non-Viral Gene Delivery Techniques to Human Adipose-Derived Mesenchymal Stem Cell

Mesenchymal stem cells (MSCs) hold tremendous potential for therapeutic use in stem cell-based gene therapy. Ex vivo genetic modification of MSCs with beneficial genes of interest is a prerequisite for successful use of stem cell-based therapeutic applications. However, genetic manipulation of MSCs is challenging because they are resistant to commonly used methods to introduce exogenous DNA or RNA. Herein we compared the effectiveness of several techniques (classic calcium phosphate precipitation, cationic polymer, and standard electroporation) with that of microporation technology to introduce the plasmid encoding for angiopoietin-1 (ANGPT-1) and enhanced green fluorescent protein (eGFP) into human adipose-derived MSCs (hAD-MSCs). The microporation technique had a higher transfection efficiency, with up to 50% of the viable hAD-MSCs being transfected, compared to the other transfection techniques, for which less than 1% of cells were positive for eGFP expression following transfection. The capability of cells to proliferate and differentiate into three major lineages (chondrocytes, adipocytes, and osteocytes) was found to be independent of the technique used for transfection. These results show that the microporation technique is superior to the others in terms of its ability to transfect hAD-MSCs without affecting their proliferation and differentiation capabilities. Therefore, this study provides a foundation for the selection of techniques when using ex vivo gene manipulation for cell-based gene therapy with MSCs as the vehicle for gene delivery.     

Directed Self‐Assembly as a Route to Ferromagnetic and Superparamagnetic Nanoparticle Arrays

Block co‐polymer patterns are attractive candidates for nanoparticle assemblies. Directed self‐assembly of block co‐polymers in particular allows for long range ordering of the patterns, making them interesting scaffolds for the organization of magnetic particles. Here, a method to tune the channel width of polymer‐derived trenches via atomic layer deposition (ALD) of alumina is reported. The alumnia coating provides a much more thermally robust pattern that is stable up to 250 °C. Using these patterns, magnetic coupling in both ferromagnetic and superparamagnetic nanocrystal chains is achieved.     

Strategies in fed-batch cultivation on the production performance of Lactobacillus salivarius I 24 viable cells

Food Science and Biotechnology - The potential use of fed-batch cultivation (FBC) for improvement of the production of Lactobacillus salivarius I 24 biomass for subsequent use as probiotics was...