J. W. Qian

On the convergence analysis and parameter selection in particle swarm optimization

A PSO with increasing inertia weight, distinct from a widely used PSO with decreasing inertia weight, is proposed in this paper. Far from drawing conclusions from sole empirical study or rule of thumb, this algorithm is derived from particle trajectory study and convergence analysis. Four standard test functions are used to confirm its validity finally. From the experiments, it is clear that a PSO with increasing inertia weight outperforms the one with decreasing inertia weight, both in convergent speed and solution precision, with no additional computing load.

Robust PID controller design using particle swarm optimizer

A simple but feasible Robust PID (RPID) tuning methodology is proposed in this paper. Most robust controllers that have been developed in literature by now have complex structures. They are either hard to be implemented or easily broken down. The simplest controller, PID, is chosen to be the prototype of robust controller. Through parameter selection, robust performance is achieved. Minimax criterion guarantees a set of controller parameters to be most optimal to the worst operating condition that may occur within the uncertainty ranges of model parameters. To execute the minimax search, a co-evolutionary algorithm based on Particle Swarm Optimization is advanced. Simulations are presented to demonstrate the advantages of RPID compared with other PIDs.

Influence of viscosity slope coefficient of CA and its blends in dilute solutions on permeation flux of their films for MeOH/MTBE mixture

Viscosity slope coefficients (b) for cellulose acetate (CA) dissolved in four solvents tetrahydrofuran (THF), dioxane (DIO), acetone (AC) and butanone (MEK), for CA in THF at different temperatures and for CA/polyvinylbutyral (PVB) in DIO have been studied. The permeation flux (J) of the CA films from four solvents, CA film from THF at different temperatures and CA/PVB blended films from DIO for separating MeOH/MTBE (methyl tert-butyl ether) mixture with 3 wt.% MeOH were measured. It was found that the b and J values for CA, CA/PVB blends and their films were different, and the J values were inverse proportional to the b values. This opposite relationship between J and b could be due to the solvent solvating power, which alters b, and also the degree of coil overlap and the bulk density of polymer films.

Assessment of polymer flow improvers for crude oil by viscometry

A new parameter has been developed to assess the efficiency of polymer flow improvers for waxy crude. The flow parameter, Q, depends on the interaction parameter for polymer-wax and polymer-resin-asphaltene, and is calculated by dilute solution viscometry. It was established that the improvement in rheological properties of doped crude oil, such as the reduction of apparent viscosity, pour point and temperature of wax crystallization, is inversely proportional to the Q values for the polymer-wax and polymer-resin-asphaltene mixtures.

FIR filter design: frequency sampling filters by particle swarm optimization algorithm

Based on the study of FIR filter design, a new method of designing frequency sampling filter is presented in this paper. By applying particle swarm optimization (PSO) to optimize transition sample values, the maximum stop band attenuation in FIR filter is obtained. The simulations of designing low-pass FIR have been done and the simulation results show that the method of FIR filter design proposed in this paper is better than the method of genetic algorithm (GA) and immune algorithm (IA) not only in the convergence speed but also in the performance of filter.

Solvent effect on the action of ethylene–vinyl acetate copolymer pour point depressant in waxy solutions

The flowability and thermal behavior of waxy solutions with and without an ethylene–vinyl acetate copolymer (EVA) have been studied. The drastic changings of pour point depression (ΔTpp) and the crystallization in four waxy solutions were observed. These changes were linear with the U-interaction parameters between EVA and wax in different solvents, suggesting that the efficiency of EVA pour point depressent depends on its compatibility with wax, which is affected by solvent.

Association of ethylene vinyl acetate copolymer in dilute solutions. V. Stability and pour point depression to wax solutions

The stability of two kinds of aggregation states of ethylene vinyl acetate (EVA) copolymer in dilute solution of 1,2-dichloroethane has been investigated by viscometry. It was found that good storage-time, shearing, and dilution resistance were displayed for both states of EVA molecule with intra- and interchain association. And for the pour point depression of wax solution doped with EVA, the EVA in intrachain aggregation state was better than the EVA in interchain aggregation state.

The application of dynamic principal component analysis to enhance chunk monitoring of an industrial fluidized-bed reactor

Dynamic principal component analysis(DPCA) is an extension of conventional principal component analysis (PCA) for dealing with multivariate dynamic data. We adopted DPCA to enhance chunk monitoring of an industrial fluidized-bed reactor, overcoming the shortcomings of conventional monitoring schemes. The appropriate methods for application of DPCA were proposed, such as combining parallel analysis and Akaike information criterion (AIC) or Bayesian information criterion @IC) to determine the number of lagged variables, using empirical reference distribution (Em) based non-parametric control limits for the statistics which do not follow theoretical distribution, and adopting data smoothing to reduce the idluence of the noises. A DPCA model for chunk monitoring is constructed using the industrial data and its effectiveness is verified.

Synthesis and hydrolysis study of polyacrylates containing 2',5-dichloro-4'-nitrosalicylanilide

Monomers (meth)acryloyloxy-2′,5-dichloro-4′-nitrosalicylanilide have been synthesized by treating 2′,5-dichloro-4′-nitrosalicylanilide (niclosamide) with acryloyl or methacryloyl chloride, and polymerized by free radical polymerization to give a polymer containing chemically bonded niclosamide. The structure of monomer and polymer were confirmed by IR, UV, and elemental analysis. Hydrolysis data of polymer in different media indicated that the hydrolysis rates of polymer were strongly dependent on the nature of the polymer structure and the hydrolyzing medium.

Delay system identification using global optimization methods

Delay system identification problem is studied in this paper. Converting to an optimization problem, a method using global optimization algorithms is proposed to identify concurrently all the parameters, including both continuous variables, such as the coefficients of the model, and discrete variable, time delay. Two global optimization methods, tabu search (TS) and simulated annealing (SA), are developed to deal with this problem. Simulation results show that both the TS and SA methods can identify the delay system successfully.