Parallel variable neighbourhood search algorithms for job shop scheduling problems

^** Email: msevkli{at}fatih.edu.tr^*** Corresponding author. Email: mehmetaydin{at}acm.org, mehmet.aydin{at}beds.ac.uk Variable neighbourhood search (VNS) is one of the most recentmetaheuristics used for solving combinatorial optimization problemsin which a systematic change of neighbourhood with a local searchis carried out. However, as happens with other metaheuristics,it takes a long time to reach some useful solutions while solvingsome sort of hard combinatorial problems such as job shop scheduling(JSS). Parallelization is one of the most considerable policiesto overcome this matter. In this paper, firstly, a number ofVNS algorithms are examined for JSS problems and then four differentparallelization policies are taken into account to determineefficient parallelization for VNS algorithms. The experimentationreveals the performance of various VNS algorithms and the efficiencyof policies to follow in parallelization. In the end, the unilateral-ringtopology, a noncentral parallelization method, is found as themost efficient policy.     

On the comparison of two different solutions in the form of series of the governing equation of an unsteady flow of a second grade fluid

In this paper, two different solutions in the form of series of the governing equation of unsteady flow of a second grade fluid are considered. These are series expansions with respect to inverse power of time and a perturbation expansion. Two illustrative examples are given. One of them is the unsteady flow of a second grade fluid over a plane wall suddenly set in motion and the other is the diffusion of a line vortex in a fluid of second grade. It is a remarkable fact that the expression of the series expansion with respect to inverse power of time is exactly in the same form as that of the perturbation expansion. Thus, it is possible to replace a series expansion with respect to inverse power of time with a perturbation expansion.     

238U, 234U and 226Ra concentrations in mineral waters and their contribution to the annual committed effective dose in Turkey

Activity concentrations of ²³⁴U, ²³⁸U and ²²⁶Ra in mineral waters were determined on the basis of nine water bottling facilities using alpha particle spectrometry. The mineral water samples were collected from three geographic regions of Turkey. The radiochemical separation used in the uranium analysis is based on the isolation of uranium radioisotopes from other radionuclides such as Th, Am, Pu and Np using UTEVA resin. Alpha sources were prepared using electrodeposition method. The activity concentration of ²²⁶Ra was determined after deposition on a membrane using BaSO₄ co-precipitation method. The activity concentrations (mBq L^?1) of ²²⁶Ra, ²³⁸U and ²³⁴U ranged from <0.56 to 165, from <0.42 to 439 and from <0.42 to 464, respectively. The measured activity concentrations were used for the calculation of the average total annual effective ingestion doses for children and adults. The committed effective doses were calculated for three different scenarios according to mineral water consumption rate. In the most extreme scenario (for age group 12–17), all water samples except MW1 and MW2 cause annual committed effective doses below the reference level (0.1 mSv year^?1) recommended by World Health Organization (WHO).     

In-plane conductivity of a layered large-bipolaron liquid

Distinctive normal-state properties of cuprate superconductors follow from their charge carriers forming a large-bipolaron liquid. The very weak scattering of the liquid’s slow-moving heavy-massed excitations by acoustic phonons yields a scattering rate that is less than the Debye frequency. The liquid’s moderate mobility, >1 cm²/V-sec at 300 K, results from its weak scattering compensating for its large mass. In resolution of a long-standing dilemma, the dc resistivity resulting from scattering by long-wavelength phonons remains nearly proportional to temperature to well below the Debye temperature. Above the Debye frequency, the frequency-dependent conductivity is dominated by excitation and photo-ionization of the liquid’s self-trapped electronic carriers. Below the Debye frequency, the frequency-dependent conductivity is dominated by the liquid’s Drude-like collective motion. The ‘gap’ between these two domains sharpens with decreasing temperature as phonon scattering of the liquid’s collective excitations diminishes. The high-frequency electronic excitations survive in the superconducting state.     

Permutation Based Design of Orthogonal Block Transforms and Filter Banks

In this work, a new efficient design techniquefor orthogonal block transforms, lapped orthogonal transformsand 4-channel perfect reconstruction subband filter banks isdeveloped. The technique consists of permutation and sign changeoperations on a reference vector. This approach can be thoughtof as a generalization of the Hadamard transform in the sensethat the reference vector h ₀ (which will be a prototype low-pass filteralso forming one of the basis functions of the transform) willin general have components that are not identically 1's. Thedesign technique, a constructive method based on Hadamard arrays,provides a convenient means to explore new transforms. The meritof our method is that the number of unknowns and equality constraintsare both reduced significantly which render the design proceduremuch more feasible while guaranteeing at the same time linearphase.     

Impulsive noise suppression from images with Jarque-Bera test based median filter

A novel impulsive noise (IN) eliminator filter, entitled Jarque–Bera test based Median Filter (JM), which shows a high performance at the restoration of images distorted by IN is proposed in this paper. The JM uses statistical methods in order to find out the corrupted pixels more accurately. The JM replaces only those corrupted pixels with the values obtained from standard median filter as explained in the paper. The simulation results reveal that the proposed filter shows better performance than the other filters mentioned in this paper in the cases of being effective in noise suppression and detail preservation, especially when the noise ratio is very high.     

Diffusion of a line vortex in a second-order fluid

In this paper, the diffusion of a line vortex in a second-order fluid is considered. The Hankel transform is used to solve this problem and an exact solution for the velocity distribution is found in terms of a definite integral. The integrand is an oscillatory function and the integration is performed by a numerical technique. It is found that there are pronounced effects of viscoelastic properties on the velocity distribution with respect to that of the Newtonian fluid.     

Transmission de la chaleur à un fluide visqueux se mouvant autour d'une sphère tournante

Summary The problem investigated is the temperature distribution in an incompressible viscous fluid past a rotating sphere. The cases in which the thermal conductivity of the sphere is large and small are considered separately.     

Transmission de la chaleur à un fluide visqueux se mouvant entre deux sphères concentriques tournantes

Summary The problem investigated is the temperature distribution in an incompressible viscous fluid moving between two concentric rotating spheres whose temperatures are maintained constant, i.e. the inner sphere temperature isT _a and that of the outer sphereT _b .     

Synthesis of thiol functionalized poly(meth)acrylates through enzymatic catalysis and a subsequent one pot reaction process

The synthesis and modification of thiol functionalized poly(meth)acrylates using a straightforward reaction concept that consists of an enzymatically catalyzed monomer synthesis, free radical polymerization and post-polymerization modification is presented. The well-known enzymatic transacylation of methyl acrylate and methyl methacrylate that runs under mild and environmentally friendly conditions was used to synthesize thiol protected acrylic and methacrylic monomers. Upon free radical polymerization and subsequent removal of protection groups, polymers with pendant thiol groups are obtained, which, in turn, can react in situ with Michael acceptors to form thiol-ene reaction products. The exceptional advantage of the proposed method is that upon removal of the enzyme from the monomer mixture, the polymerization, deprotection of thiols and subsequent Thio-Michael-type addition reaction can be conducted in one pot without purification of the intermediate products. Furthermore, the different reactivities of acetyl and benzoyl protection groups in lipase catalyzed reactions are discussed.