Design of a simplified adaptive fuzzy backstepping control for uncertain discrete-time nonlinear systems

This paper presents a simplified adaptive fuzzy backstepping control for uncertain discrete-time nonlinear systems. It is assumed that the systems are described by a discrete-time equation with nonlinear uncertainties to be viewed as the modelling errors and the unknown external disturbances, and the states are observed with measurement noises. To design the simplified adaptive fuzzy backstepping control, the modelling errors are approximated by using the fuzzy inference approach based on the extended single-input rule modules, and the estimates for the unmeasurable states and the adjustable parameters are derived by using the weighted and its simplified weighted least squares estimators. It is proved that the states are ultimately bounded, and the estimation errors remain in the vicinity of zero. The effectiveness of the proposed approach is indicated through the simulation experiment of a simple numerical system.     

Adaptive fuzzy dynamic surface control for a class of stochastic MIMO discrete-time nonlinear pure-feedback systems with full state constraints

This paper presents the design of an adaptive fuzzy dynamic surface control for a class of stochastic MIMO discrete-time nonlinear pure-feedback systems with full state constraints using a set of noisy measurements. The design approach is described as follows. The nonlinear uncertainty is approximated by using the fuzzy logic system at the first stage, secondly the proposed adaptive fuzzy dynamic surface control is designed based on a new saturation function for full state constraints, thirdly the number of the adjustable parameters is reduced by using the simplified extended single input rule modules, and finally the simplified weighted least squares estimator is in a simplified structure designed to take the estimates for the un-measurable states and the adjustable parameters. The simulation provides that the proposed approach is effective for the improvement of the system performance.     

Convective cloud discrimination using multi-frequency microwave signatures of the AMSR-E sensor: evaluation over the Tibetan Plateau

Multi-frequency passive microwave remote sensing affords a unique opportunity to understand various phenomena; low-frequency microwaves penetrate clouds and are able to observe Earth surface conditions (～6–18 GHz), while the higher frequencies are strongly impacted by prevailing atmospheric conditions. By using these relationships, an atmospheric opacity index (AOI) using Advanced Microwave Scanning Radiometer on Earth Observing Satellite (AMSR-E) multi-frequency data is proposed. This index utilizes four AMSR-E frequencies spanning both high- and low-microwave frequency. This AOI can be used to discriminate cloudy atmosphere from clear-sky conditions.

This index shows good agreement with current cloud indices. In this research, it is compared against the Moderate Imaging Spectroradiometer (MODIS) and the Geostationary Operational Environmental Satellite 9th series (GOES-9) atmosphere products. It offers the possibility of detecting convective clouds at all times (day and night) due to the advantage of the independence of the microwave sensors on the Sun for illumination.     

Esquentian of the mean by three stage procedure

Let X₁, X₂... be i.i.d. observations with mean μ and variance σ², and suppose that given a sample of size n one wishes to estimate μ by X_n, subject to the loss function L_n= A²(X_n-μ)²+n. When σ² is unknown, the optimal sample size n₀ for minimizing the risk R_n = E{L_n} cannotbe found. To resolve this problem, Robbins (1959) proposed a sequential procedure whenX_i is normally distributed, and then the asymptotic properties have been extensively studied. In this paper, we apply Hall's three stage procedure to the problem without specifying the distribution of X_i and derive the second order asymptotic expansions of the expected sample size and the risk.     

sequential estimation of the hgarginal density function for a strongly mixing process

Suppose that {X_n} is a strongly mixing process with unknow marginal density f(x) and that we estimate f(x) by a kernel estimator [fcirc]_n(x|h_n)and want to achive the MISE no larger than some preassigned postive number w. However,the appropriate sample size n^*depends on a functional of the unknow density function. Therefore some sequential procedure is required and we adopt a fully sequential procedure. In this paper we investigate the asymptotic properties of the procedure and show that the producure is asymptotically efficient in a certain sense as w→0. The results are almost the same in the i.i.d. setting. our result extend a class of models to which the methodology can be applied. For example economic variable,experiments on a single subject in which obervation are not indepent, and so on.     

Effect of Firing Temperature on the Thermal Stability of Low-Oxygen Silicon Carbide Fibers

Low-oxygen SiC fibers which were fabricated by curing with electron-beam irradiation and firing at 1273 and 1573 K (fiber-A and fiber-B) were exposed at 1673 to 1973 K. Significant differences in surface composition, crystallinity, specific resistivity, and tensile strength were found between fiber-A and fiber-B. On exposing the fibers to high temperatures, they both crystallized nearly completely into intermixed β-SiC and free carbon, and consequently the resistivity decreased markedly. Deep voids were formed at the surface of fiber-A as a result of rapid dehydrogenation at the earliest stage of high-temperature exposure. On the other hand, fiber-B, which decomposed mildly, had a dense pore-free structure. The fiber strength was proportional to the reciprocal square root of SiC crystal size. At the same crystal size, the strength of fiber-A was lower because of the surface flaws.     

Photo‐reductive fading of disperse azo dyes on nylon substrate: thermochemical analyses of reactions of photo‐induced radicals using the semiempirical molecular orbital method†

When the excited triplet states of disperse azo dyes with nitro groups abstract hydrogen to generate hydrazinyl (from azo groups) and nitrosyl hydroxide radicals (from nitro groups), both the radicals as H‐acceptors carry out azo scission, conversion to nitrogen dioxide via disproportionation reactions and self‐decomposition via rearrangement. A kinetic equation was formulated by the sum of these reactions, which describes the initial rates (K_PA) of reductive fading. The K_PA values were controlled by the rate constants of the reactions of hydrazinyl and nitrosyl hydroxide radicals as H‐acceptors, which were estimated by thermochemical analyses of the reactants, intermediates and end products using the semiempirical molecular orbital PM5 method, and by the concentrations of the reactants: H‐acceptors and H‐donors. The K_PA values observed for 12 dyes were explained semi‐quantitatively by multiple routes of reactions depending upon to what extent each radical reaction was thermochemically favoured.     

Microstructure development in Sb2O3-doped ZnO

The microstructure development in Sb₂O₃-doped ZnO was studied at doping levels up to 2.0 mol%. Dopant Sb₂O₃ reacted with ZnO to form inclusion particles,α-Zn₇Sb₂O₁₂, and inhibited the grain growth of ZnO. With increasing doping level of Sb₂O₃, the growth rate of ZnO decreased whereas that of inclusion particles increased. Some inclusion particles were trapped in ZnO grains at low doping levels of Sb₂O₃, but the volume fraction of trapped inclusion particles decreased with increasing doping level. Stereological analysis of the size and number ratios of ZnO grains and inclusion particles indicated that a compatible assumption is needed to evaluate Zener effect in two-phase sintering.