A novel binary gaining–sharing knowledge-based optimization algorithm for feature selection

Neural Computing and Applications - To obtain the optimal set of features in feature selection problems is the most challenging and prominent problem in machine learning. Very few human-related...     

More on jitter effects on sinewave measurements

The measurement of signal-to-noise ratio (SNR) based on uniform sampling is investigated and compared with the results of Y. Jenq (see ibid., vol.37, p.245-251, June 1988) based on non-uniform sampling. Simulation results are provided to confirm the theoretical work. The authors then investigate amplitude and phase measurements and present new formulae for its statistics, which are more accurate than in their previous work (see ibid., vol.39, p.86-89, Feb. 1990). The approach followed in this study is also suitable for investigating signal measurements in the presence of other noise forms, e.g. quantization     

Effect of sampling jitter on some sine wave measurements

The effect of sampling jitter on some periodic signal measurements, namely, the amplitude and phase of a pure sinusoid, is investigated. The parameters are determined by the fast Fourier transform (FFT) algorithm, which is used for manipulating samples in a data-acquisition system. Results are expressed in terms of mean values and variances of the measured parameters. Computer simulation results, based on Gaussian jitter, show the changes of amplitude and phase standard deviations versus the changes of standard deviation of jitter and signal amplitude for different numbers of FFT points     

Photovoltaic powered regulated cathodic protection system

The cathodic protection (CP) system objective is to protect metallic structures against corrosion caused by chemical reaction between metallic structures and surrounding mediums, such as soil or water. To overcome such a problem, a sacrificing anode is connected to the protected structure (which acts as a cathode) through a DC power supply. As a result, a current passes from the sacrificing anode to the protected cathode. This leads to anode corrosion rather than causing the cathode (protected structure) corrosion. To stop the corrosion, the protected structure requires a constant current determined by structure metal, area, and the surrounding medium. The major difficulty in achieving this condition is the variation of surrounding medium resistivity due to climatic condition changes. For example, rains as well as humidity decrease soil resistivity, and as a result the DC current increases and a harmful overprotection may take place. Both corrosion and overprotection are harmful for the metallic structure. Conventional CP systems resolve this problem by manual adjustment of DC voltage periodically to obtain a constant current. Such adjustment depends on the personal experience of the technician and the accuracy of the measuring equipment used. Accordingly, the adjustment is subject to personal and measuring equipment errors. Moreover, if the interval between two successive adjustments is relatively long, structure corrosion becomes significant, which may have drastic consequences. To overcome the aforementioned difficulties associated with the conventional CP system, an automatically regulated CP system is discussed in this article. The proposed system senses the variations of the surrounding medium resistivity and adjusts the DC voltage of the system automatically so that the DC current is kept constant at the required level. The design of a solar photovoltaic system to supply the CP system by the required DC power is also discussed.     

A novel differential evolution algorithm for solving constrained engineering optimization problems

This paper introduces a novel differential evolution (DE) algorithm for solving constrained engineering optimization problems called (NDE). The key idea of the proposed NDE is the use of new triangular mutation rule. It is based on the convex combination vector of the triplet defined by the three randomly chosen vectors and the difference vectors between the best, better and the worst individuals among the three randomly selected vectors. The main purpose of the new approach to triangular mutation operator is the search for better balance between the global exploration ability and the local exploitation tendency as well as enhancing the convergence rate of the algorithm through the optimization process. In order to evaluate and analyze the performance of NDE, numerical experiments on three sets of test problems with different features, including a comparison with thirty state-of-the-art evolutionary algorithms, are executed where 24 well-known benchmark test functions presented in CEC’2006, five widely used constrained engineering design problems and five constrained mechanical design problems from the literature are utilized. The results show that the proposed algorithm is competitive with, and in some cases superior to, the compared ones in terms of the quality, efficiency and robustness of the obtained final solutions.     

A novel flash fast-locking digital phase-locked loop: design and simulations

A flash digital phase-locked loop (DPLL) is designed using 0.18 μm CMOS process and a 3.3 V power supply. It operates in the frequency range 200 MHz?2 GHz. The DPLL operation includes two stages: (i) a novel coarse-tuning stage based on a flash algorithm similar to the algorithm employed in flash A/D converters, and (ii) a fine-tuning stage similar to conventional DPLLs. The flash portion of the DPLL is made up of frequency comparators, an encoder and a decoder which drives a multiple charge pump (CP)/lowpass filter (LPF) combination. Design considerations of the flash DPLL circuit components as well as implementation using Cadence design tools are presented. Spectre simulations were also performed and demonstrated a significant improvement in the lock time of the flash DPLL as compared to the conventional DPLL. By increasing the number of frequency comparators, the lock time is expected to be always less than 100 ns in the above-mentioned frequency range.     

Determination of intrinsic viscosity of polymeric compounds through a single specific viscosity measurement

A modified method based on a combination of the Huggins and Schulz–Blaschke equations is proposed which enables the determination of intrinsic viscosity [η] from the measurement of a single specific viscosity. The method has been verified for different polymer samples having a wide range of [η] values and showed a variation of <±6×10⁻³% from the values obtained by Huggins extrapolation method     

Gaining-Sharing Knowledge Based Algorithm for Solving Stochastic Programming Problems

This paper presents a novel application of metaheuristic algorithms for solving stochastic programming problems using a recently developed gaining sharing knowledge based optimization (GSK) algorithm. The algorithm is based on human behavior in which people gain and share their knowledge with others. Different types of stochastic fractional programming problems are considered in this study. The augmented Lagrangian method (ALM) is used to handle these constrained optimization problems by converting them into unconstrained optimization problems. Three examples from the literature are considered and transformed into their deterministic form using the chance-constrained technique. The transformed problems are solved using GSK algorithm and the results are compared with eight other state-of-the-art metaheuristic algorithms. The obtained results are also compared with the optimal global solution and the results quoted in the literature. To investigate the performance of the GSK algorithm on a real-world problem, a solid stochastic fixed charge transportation problem is examined, in which the parameters of the problem are considered as random variables. The obtained results show that the GSK algorithm outperforms other algorithms in terms of convergence, robustness, computational time, and quality of obtained solutions.     

Analysis of an ice-condenser containment building anchorage system

A 3-D non-linear finite-element analysis of an ice-condenser steel containment anchorage system, which considers the parameters that affect this complex system, was performed. The model included a portion of the containment shell, knuckle plate, base plate, reinforced concrete mat, anchor bolt, anchorage system, soil foundation material, and a portion of the containment shield building. The results showed the early formation of conical failure surfaces within the concrete that are associated with the brittle failure mode. However, these surfaces were not completely developed to the top of the containment basemat. No high strains were recorded in the anchorage system or the containment shell. Hence, failure of the containment anchorage system was not hypothesized.