自适应模糊算法在光伏系统MPPT中的应用

针对光伏电池的非线性特性,介绍了最大功率点跟踪的原理,并详细分析了常规控制算法在光伏系统最大功率跟踪控制中的优缺点,提出将自适应模糊控制算法应用到光伏系统最大功率点跟踪的控制中,自适应模糊控制能快速响应外界环境的变化,在最大功率点无明显振荡现象.实验结果表明,该方法能使系统稳定工作在最大功率点,同时能对外界环境的变化做出快速反应.     

Comparison of eluted monomer from different indirect and direct resin composites

Indirect resin composites used in indirect restorations have been used as alternative methods to avoid the negative effects of a direct application. The composition and structure of these are similar to a direct composite. Several authors have discussed the elution monomer from resin composites because it is a crucial factor in optimizing the physical properties and biocompatibility of resin composites. The aim of this study was to compare the elution of monomers from different resin composites using high-performance liquid chromatography (HPLC). Indirect composites including Signum, Gradia, and Solidex, and direct composite Filtek Ultimate were used. The samples (2 x 5 mm) were prepared and polymerized for 20 seconds with a light-emitting diode unit. A secondary curing was then applied to the indirect resin composites. After fabrication, each sample was immediately immersed in a 75 wt% ethanol/water solution and analyzed by HPLC. The obtained data were analyzed with one-way ANOVA and Tukey HSD (p < 0.05). Residual monomers were eluted from indirect and direct resin composites and the amount of eluted monomers increased over time. The highest mean concentrations of residual Bis-GMA, UDMA, TEGDMA, and HEMA were detected with the Filtek Ultimate (2,342 µM), Solidex (7,908 µM), Signum (2.8 µM), and Filtek Ultimate (9.7 µM), respectively. The highest amount of eluted monomer concentrations detected was viewed as critical for toxic reactions in human cells.     

An alternative one sided test of normal mean

This paper provides an alternative test procedure for the problem oftesting of normal mean for one sided alternative when the variance is known in case of costly trials. The proposed test is based on a sampling scheme which we call 'continuous adaptive design'. Some exact andasymptotic results related to the test and design are studied.     

Recursive estimation of quantitles using recursive kernel density estimators

Recursive estimation of quantiles may be obained via adaptive stochastic approximation

approximation theorms can be used to obtained the asympotic properties when the obervation are independent. for dependent sequences matingale theory cannot be applied straight forwardly as the tool for asympototic analysis.In this paper we consider both the case when the observation are i.i.d. and when they form a stationary and strongly regular process.the main result is sufficient condition for almost sure convergence in the strongly regular case.     

Optimal allocation for estimating the mean of a bivariate polynomial

Suppose we wish to estimate the mean of some polynomial function of random variables from two independent Bernoulli populations, the parameters of which. rhemselves, are modeled as independent beta random variables. It. is assumed that the t.otal sample size for the experiment is fixed, but that the number of experimental units observed from each population may be random. This problem arises, ior example, when estimating the fault tolerance of a system by testing its compomentc individually. Using a decision theorebic approach, we seek to minimize the Bayes risk that arises from using a squared error loss function The Bayes estimator can lw detrmined in a straightforwardmanner, so the problem of optimal estimation rcduces. therefore, to a problem of optimallocatton of the samples between the two populatiorls. This can be solved via dynamic programming. Similar programming techniques are utilized to evaluate properties of a number of ad hoc allocation strategies that might also be collsidered for use in this problem.Two sample polynomials are analyzed along with a number of examples indicating the effects of different prior parameter settings. The effects of differences between prior pararueters used in the design and analysis stages of the experiment are also examined. For the polynomials considered, the adaptive strategies are found to be especially robust. We discuss computational techniques that facilitate such analyses by permitting rapid re-evaluation of strategies. Capabilities of this sort enrouragepeople to explorr designs more fully and to consider them from a number of different viewpuillts.     

基于图像纹理清晰度的数字水印算法

为了提高嵌入水印图像的视觉效果和解决自适应调节参数简单的问题,借鉴了离散小波变换下纹理特征清晰度分析评价标准的思想,对文献[1]提出的分块自适应水印算法做出了改进,并提出了一种改进的水印算法.对图像离散小波变换的近似子带进行分块和纹理特征计算处理,对纹理特征计算值进行分类和确定对应分类的嵌入强度,将水印信息嵌入到近似子带分块SVD(奇异值分解)的S矩阵中.实验结果表明,通过纹理清晰度分析出来的自适应效果好于文献[1]中提到的方法,PSNR=70,NC=0.9926,而且水印信息具有良好的鲁棒性和不可见性.     

Design study of a 120-keV,3He neutral beam injector

We describe a design for a 120-keV, 2.3-MW,³He neutral beam injector for use on a D-³He fusion reactor. The constraint that limits operating life when injecting He is its high sputtering rate. The sputtering is partly controlled by using an extra grid to prevent ion flow from the neutralizer duct to the electron suppressor grid, but a tradeoff between beam current and operating life is still required. Hollow grid wires functioning as mercury heat pipes cool the grid and enable steady state operation. Voltage holding and radiation effects on the acceleration grid structure are discussed. We also briefly describe the vacuum system and analyze use of a direct energy converter to recapture energy from unneutralized ions exiting the neutralizer. Of crucial importance to the technical feasibility of the³He-burning reactor are the injector efficiency and cost; these are 53% and $5.5 million, respectively, when power supplies are included.The beam is composed of 91 separate, parallel currents that flow in the gaps between the elements or wires of a grid. Each such flow is referred to as a beamlet. The current densities in Figs. 5, 8, and 9 are values within a beamlet, as measured at the beam-forming grid. They are not values averaged over the entire beam cross-section.     

直接序列扩频在矿井通信中的应用

分析了矿井环境对矿井通信系统的影响,阐述了直接序列扩频通信的原理,指出了直接序列扩频技术的抗干扰特点,并给出了该通信模式的模型、基于扩频芯片Z2000的矿井通信的具体实现方案。