A hybrid of genetic algorithm and particle swarm optimization for recurrent network design

An evolutionary recurrent network which automates the design of recurrent neural/fuzzy networks using a new evolutionary learning algorithm is proposed in this paper. This new evolutionary learning algorithm is based on a hybrid of genetic algorithm (GA) and particle swarm optimization (PSO), and is thus called HGAPSO. In HGAPSO, individuals in a new generation are created, not only by crossover and mutation operation as in GA, but also by PSO. The concept of elite strategy is adopted in HGAPSO, where the upper-half of the best-performing individuals in a population are regarded as elites. However, instead of being reproduced directly to the next generation, these elites are first enhanced. The group constituted by the elites is regarded as a swarm, and each elite corresponds to a particle within it. In this regard, the elites are enhanced by PSO, an operation which mimics the maturing phenomenon in nature. These enhanced elites constitute half of the population in the new generation, whereas the other half is generated by performing crossover and mutation operation on these enhanced elites. HGAPSO is applied to recurrent neural/fuzzy network design as follows. For recurrent neural network, a fully connected recurrent neural network is designed and applied to a temporal sequence production problem. For recurrent fuzzy network design, a Takagi-Sugeno-Kang-type recurrent fuzzy network is designed and applied to dynamic plant control. The performance of HGAPSO is compared to both GA and PSO in these recurrent networks design problems, demonstrating its superiority.     

Mass transfer of sodium chloride in simulated crystallizing pond during the rainfall period

The mass transfer equation describing the transport phenomena of sodium chloride is derived for the simulated crystallizing pond during the rainfall period. According to the theoretical and experimental results, the dissolution rate of NaCl is shown to be controlled by the combination of salt transport including the diffusion and convection of solute in solution and surface dissolution reaction including the desorption and surface diffusion of solute. It is found that both the dissolution and convective mass transfer coefficients are proportional to the total rainfall quantity, and inversely proportional to the brine depth. The variation of dissolution mass transfer coefficient to the total rainfall quantity and brine depth is correlated from the experimental results. Correlation of the convective mass transfer coefficient is also obtained by using the numerical solution of the mass transfer equation.     

A fundamental multivariable robustness theorem for robusteigenvalue assignment

A fundamental robustness theorem for robust eigenvalue assignment of multivariable feedback systems is derived. The theorem determines whether a perturbed multivariable feedback system has its characteristic polynomial zeros located in the same regions as the nominal system does. It can be applied to continuous systems as well as to discrete systems. The theorem can handle nonsquare transfer matrices as well as dynamic output feedback. Conditions are discussed under which the proposed theorem reduces to a fundamental theorem for stability robustness analysis     

Miniaturized 3 GHz cross-coupled planar microwave filters

Cross-coupled planar microwave filters were fabricated using YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// superconducting thin films deposited on both sides of a LaAlO/sub 3/ single crystal substrate by pulsed laser deposition. The hairpin resonator geometry allows one to miniaturize the 3-GHz filters by compacting the entire filter onto a substrate with dimensions 0.5 cm /spl times/ 1 cm. By adjusting the relative spacing among the resonators to establish adequate couplings, filters with very sharp rejection skirt and extremely small insertion loss in passband were obtained.     

Rate and mechanism of divalent metal transport through supported liquid membrane containing di(2-ethylhexyl) phosphoric acid as a mobile carrier

The rate and mechanism of copper, cobalt, nickel and zinc transport through a supported liquid membrane containing di(2-ethylhexyl) phosphoric acid as a mobile carrier were studied, respectively. The permeation rate equations have been derived taking into account aqueous film diffusion, interfacial chemical reaction and membrane diffusion as simultaneous controlling steps. The possible rate-controlling steps were estimated by comparing the relative values of the three successive resistances. The measured permeation rates of zinc agreed well with the proposed mechanism in this study.     

Fuzzy pattern recognition of tungsten inert gas weld quality

In this paper, a fuzzy pattern recognition technique is applied to classifying aluminium weld quality in tungsten inert gas (TIG) welding. The pattern vector includes three components, that is, the front height, the back height, and the front width of weld. Based on the values of the pattern vector, good, fair, and poor weld qualities can be automatically classified by using the fuzzy pattern recognition technique. Experimental results under different welding parameters are presented to illustrate the proposed method.     

A silicidation-induced process consideration for forming scale-downsilicided junction

A process consideration for forming silicided shallow junctions, arising from silicidation process, has been discussed. The CoSi₂ shallow p⁺n junctions formed by various schemes are characterized. The scheme that implants BF₂⁺ ions into thin Co films on Si substrates and subsequent silicidation yields good junctions, but the problems about the dopant drive-in and knock-on of metal deeply degrade this scheme. In the regime that implants the dopant into Si and then Co deposition, however, a large perimeter leakage of 0.1 nA/cm is caused. Generation current, associated with a defect-enhanced diffusion of Co in Si during silicidation, dominates the leakage. A high-temperature pre-activation prior to Co deposition reduces the perimeter leakage to 0.038 nA/cm, but which deepens the junctions     

A projection approach to stability analysis and design of fuzzy systems

The stability analysis and design of the systems, described in Takagi-Sugeno's (TS) fuzzy model, are discussed in this correspondence. Based on the alternating projection method, the stability issue can be extended to a prescribed stability region. And the projection algorithm is proposed for assuring the desired stability. By involving the controller, we further introduce the design issues for the closed-loop system. Some numerical examples are given to demonstrate the validity and feasibility.     

Adaptive fuzzy sliding-mode controller of uncertain nonlinear systems

This paper deals with the design of adaptive fuzzy sliding-mode controllers for the T-S fuzzy model based on the Lyapunov function. It is shown that the Lyapunov function can be used to establish fuzzy sliding surfaces by solving a set of linear matrix inequalities (LMIs). The design of the fuzzy sliding surfaces and the adaptive fuzzy sliding-mode controllers is proposed. The adaptive mechanism is also used to deal with unknown parameter perturbations and external disturbances. Two examples illustrate the feasibility of the proposed methods.