An empirical investigation into the effects of chaos on different types of evolutionary crossover operators for efficient global search in complicated landscapes

In this study, a comprehensive empirical test is conducted to analyse the effects of two well-known chaotic maps, namely sinusoidal and logistic maps, on the efficacy of double Pareto crossover, Laplace crossover and simulated binary crossover operators for the global optimization of continuous problems. To do so, 13 well-known numerical benchmark problems in three distinctive dimensions, namely 50D, 100D and 200D, are considered and the genetic algorithm (GA) with simple version and chaos-enhanced versions of the mentioned crossover operators are utilized for optimizing these functions. Furthermore, a time complexity analysis is conducted to find out the impact of hybridizing the chaos and the evolutionary operators on the computational complexity of GA. The results of the experimental analysis provide us with fruitful information regarding the scalability, computational complexity and exploration/exploitation capability of the considered rival optimization algorithms, as well as, demonstrate the efficacy of chaos-evolutionary computing for numerical continuous optimizations.     

Hybrid intelligent method for fuzzy reliability analysis of corroded X100 steel pipelines

Epistemic uncertainties are critical for reliable design of corroded pipes made of high-strength grade steel. In this work, corrosion defects geometries and operating pressure are provided as the epistemic uncertainties in reliability analysis. A framework of an iterative approach-based bi-loop is presented for fuzzy reliability analysis (FRA) of corroded pipelines to evaluate the fuzzy reliability index-based various fuzzy-random variables (FRVs). In the inner loop, the conjugate first-order reliability method using adaptive finite-step size is applied for carried out the reliability analysis. The outer loop is structured based on the fuzzy analysis corresponding to a modified particle swarm optimization as an intelligent tool. The adaptive conjugate fine step size is dynamically computed to adjust the conjugate sensitivity vector in the reliability loop. The sufficient descent condition is satisfied based on three-term conjugate first-order reliability method. The performance function of corroded pipelines is defined based on average shear stress yield-based plastic flow theory, remaining strength factor, and operating pressure. Two applicable examples as corroded pipelines made from X100 high-strength steel are given to illustrate the effects of epistemic uncertainties under corrosion defects. Investigation the results has shown that modeling of epistemic uncertainty in the reliability analysis of high-grade steel pipelines could result more reasonable reliability indexes. In addition, results indicate that FRVs have significant influence on fuzzy reliability index calculations, especially corrosion defect depth and operating pressure (as FRVs). The sensitivity measure of FRA demonstrated that fuzzy reliability index of corroded X100 steel pipelines is more sensitive to the FRVs means.

     

A hybrid sufficient performance measure approach to improve robustness and efficiency of reliability-based design optimization

The stable convergence and efficiency of reliability-based design optimization (RBDO) using performance measure approach (PMA) are the major issue to develop the reliability methods based on modified chaos control (MCC), hybrid chaos control (HCC) and finite-step length adjustment (FSL). However, these methods may be inefficient for RBDO problems with convex and concave probabilistic constraints. In this paper, an adaptive modified chaos control (AMC) is proposed to provide the robust and efficient results in RBDO. The proposed AMC is adjusted using dynamical chaos control factor, which is extracted using sufficient descent condition for PMA. Using sufficient criterion, the proposed AMC is adaptively combined with advanced mean value (AMV) to improve the performance of PMA, named as hybrid adaptive modified chaos control (HAMC). Considering the robustness and efficiency, the proposed HAMC is compared with several existing reliability methods by three nonlinear structural/mathematical performance functions and two RBDO problems. The results indicate that the proposed HAMC with sufficient descent condition provides superior convergences in terms of both robustness and efficiency, compared to existing PMA methods using AMV, MCC, HCC and FSL.

     

Study the Synthesis,Characterization and Immersion of Dense and Porous Bovine Hydroxyapatite Structures in Hank’s Balanced Salt Solution

The bone-bonding potential of biomaterials is evaluated in vitro through examining the surface apatite formation in Hank’s media to enhance biocompatibility, which is also applicable to facilitate in vivo osseointegration of implantable devices. Hence, bovine hydroxyapatite (BHA) bioceramic structures have been used in various biomedical applications such as orthopedic implants. In this article, the microstructure, in vitro bioactivity, and nanomechanical properties of the synthesized dense and porous BHA are investigated via scanning electron microscopy, x-ray diffraction, energy-dispersive x-ray spectroscopy, Fourier transform infrared spectroscopy, and nanoindentation analysis. From the obtained results, porous BHA mostly possesses adequate requirements for substitution as implants in the human body.     

Simulation-based optimization of ecological leasing: a step toward extended producer responsibility (EPR)

In recent years, due to severe environmental legislations and extended producer responsibility, leasing has been recommended as a strategy for increasing resources productivity and minimizing waste generation during consumption and product end-of-life (EOL) phase. Hence, it is essential to develop a model that can help leasing company for achieving sustainable production management. In this paper, a model is developed which optimizes the environmental and economical impact of product during leasing and its EOL phase from customers and leasing company point of view. To solve the problem, simulation-based optimization approach is investigated and the integrated mathematical and simulation model is developed for incorporating uncertainty during leasing period. Finally a case study with data from industry is used to validate the approach and potential applications of the developed model are illustrated.     

Scalable Linear Array Architecture with Data-Driven Control for Ultrahigh-Speed Vector Quantization

Current and future requirements for adaptive real-time image compression challenge even the capabilities of highly parallel realizations in terms of hardware performance. Previously proposed linear array structures for full-search vector quantization do not offer scalability and adaptivity in this context, because they require separate data/control pins for dynamically updating the codevectors and complicated interlock mechanisms to ensure that the regular data flow is not corrupted as a result of updates. We explore the design space for full-search vector quantizers and propose a novel linear processor array architecture in which global wiring is limited to clock and power supply distribution, thus allowing high-speed processing in spite of only limited communication with the host via the boundary processors. The resulting fully pipelined design is not only area-efficient for VLSI implementation but is also readily scalable and offers extremely high performance.     

Structural properties of Cayley digraphs with applications to mesh and pruned torus interconnection networks

Despite numerous interconnection schemes proposed for distributed multicomputing, systematic studies of classes of interprocessor networks, that offer speed-cost tradeoffs over a wide range, have been few and far in between. A notable exception is the study of Cayley graphs that model a wide array of symmetric networks of theoretical and practical interest. Properties established for all, or for certain subclasses of, Cayley graphs are extremely useful in view of their wide applicability. In this paper, we obtain a number of new relationships between Cayley (di)graphs and their subgraphs and coset graphs with respect to subgroups, focusing in particular on homomorphism between them and on relating their internode distances and diameters. We discuss applications of these results to well-known and useful interconnection networks such as hexagonal and honeycomb meshes as well as certain classes of pruned tori.     

A Group Construction Method with Applications to Deriving Pruned Interconnection Networks

A number of low degree and, thus, low complexity, Cayley-graph interconnection structures, such as honeycomb and diamond networks, are known to be derivable by systematic pruning of 2D or 3D tori. In this paper, we extend these known pruning schemes via a general algebraic construction based on commutative groups. We show that, under certain conditions, Cayley graphs based on the constructed groups are pruned networks when Cayley graphs of the original commutative groups are kD tori. Thus, our results offer a general mathematical framework for synthesizing and exploring pruned interconnection networks that offer lower node degrees and, thus, smaller VLSI layout and simpler physical packaging. Our constructions also lead to new insights, as well as new concrete results, for previously known interconnection schemes such as honeycomb and diamond networks     

The effect of ginger on diabetic nephropathy,plasma antioxidant capacity and lipid peroxidation in rats

Oxidative stress is a major factor in the pathogenesis of diabetic complications. We studied the effects of ginger powder on nephropathy induced by diabetes, and measured changes in plasma antioxidant capacity and lipid peroxidation.     

Scattering of Harmonic Waves by a Circular Cavity in a Porous Medium: Complex Functions Theory Approach

An analytical solution for the evaluation of scattering of waves by a circular cavity in infinite isotropic elastic porous media is presented. Two groups of complex functions for solid skeleton and pore fluid in a two-dimensional complex plane are introduced in order to solve the Biot equations. Stress, displacement, and pore pressure fields induced by incident and scattered waves in the medium and especially in the vicinity of the cavity are evaluated in this complex plane. The validation of the proposed solution is shown by various numerical examples. A parametric study including the effects of fluid compressibility changes, shear modulus, and permeability variations, several wave numbers, and wave types (fast, slow, and shear waves) is performed.