一类改进的模糊Smith 预估控制系统

针对工业生产过程中常见的大时滞对象,在分析模糊Smith预估控制方案的基础上,提出一种新的控制方案,分别对模糊控制器和Smith预估器加以改进,仿真结果表明,改进后的方案具有较强的鲁棒性和较好的控制性能。     

Beyond the Zipf–Mandelbrot law in quantitative linguistics

In this paper the Zipf–Mandelbrot law is revisited in the context of linguistics. Despite its widespread popularity the Zipf–Mandelbrot law can only describe the statistical behaviour of a rather restricted fraction of the total number of words contained in some given corpus. In particular, we focus our attention on the important deviations that become statistically relevant as larger corpora are considered and that ultimately could be understood as salient features of the underlying complex process of language generation. Finally, it is shown that all the different observed regimes can be accurately encompassed within a single mathematical framework recently introduced by C. Tsallis.     

氢化物发生-电感耦合等离子体原子发射光谱法同时测定人发中氢化元素和非氢化元素

采用连续氢化物发生法,在酸性介质中,对人发样品中可形成氢化物的元素（As,Se,Pb,Hg,Sb)和棵氢化元素（Zn,Cr,Mg,Mn,Ca,Fe,Cu,Ni,Cd,Al,Co,Mo,Ba)进行同时测定。研究了酸度、NaBH4的浓度、载气流速、清洗时间对氢化元素的影响,比较了传统雾法和（雾化＋氢化法）对氢化元素和非氢化元素的影响,选择了最佳分析条件。对标准人发样品中的18种元素进行了测定,结果令人满意。     

Origin and System Effects of Polarization Mode Dispersion in Chirped Bragg Gratings

Polarization mode dispersion of chirped Bragg gratings is analyzed in terms of key birefringence phenomena and impact on telecommunication systems performance. The influence on polarization mode dispersion (PMD) of fiber birefringence, grating chromatic dispersion, and ripples of the group delay curve is pointed out. Polarization mode dispersion influence on systems performance is investigated by numerical simulations and transmission experiments at 10 Gbit/s. The deterministic nature of Bragg gratings PMD determines a moderate, upper-limited system penalty for a transmission line employing a single compensating device. However, in the case of broadband components, a non-negligible PMD penalty may be observed due to the difficulty of controlling accurately the group delay linearity.     

Exponential Dichotomy for a Nonautonomous System of Parabolic Equations

In this paper we study the existence and roughness of exponential dichotomy (ED) of a non-autonomous system of parabolic equations with Neumann boundary conditions. In order to do that, we first set the problem in the Linear Skew-Product Semiflow (LSPS) framework. Then we prove that the ED is not destroyed by small perturbation (roughness). Next, we compute the dynamical spectrum for this LSPS. Finally, under some conditions we prove that zero does not belong to the dynamical spectrum corresponding to this LSPS. i.e., the system has ED (existence).     

Brain tissue deforms similarly to filled elastomers and follows consolidation theory

Slow, large deformations of human brain tissue—accompanying cranial vault deformation induced by positional plagiocephaly, occurring during hydrocephalus, and in the convolutional development—has surprisingly received scarce mechanical investigation. Since the effects of these deformations may be important, we performed a systematic series of in vitro experiments on human brain tissue, revealing the following features. (i) Under uniaxial (quasi-static), cyclic loading, brain tissue exhibits a peculiar nonlinear mechanical behaviour, exhibiting hysteresis, Mullins effect and residual strain, qualitatively similar to that observed in filled elastomers. As a consequence, the loading and unloading uniaxial curves have been found to follow the Ogden nonlinear elastic theory of rubber (and its variants to include Mullins effect and permanent strain). (ii) Loaded up to failure, the “shape” of the stress/strain curve qualitatively changes, evidencing softening related to local failure. (iii) Uniaxial (quasi-static) strain experiments under controlled drainage conditions provide the first direct evidence that the tissue obeys consolidation theory involving fluid migration, with properties similar to fine soils, but having much smaller volumetric compressibility. (iv) Our experimental findings also support the existence of a viscous component of the solid phase deformation.Brain tissue should, therefore, be modelled as a porous, fluid-saturated, nonlinear solid with very small volumetric (drained) compressibility.     

共振光散射法(RLS)研究外源刺激对CdSe/ZnS量子点/TiO_2纳米复合物与人血清白蛋白的相互作用的影响

近似生理条件下,采用共振光散射法研究了CdSe/ZnS量子点/TiO_2纳米复合物同人血清白蛋白的相互作用,通过分析影响二者相互作用的纳米复合物浓度、pH、NaCl浓度、反应温度、检测时间、共存离子、表面活性剂、加样顺序等外源刺激因素,结果表明:新形成的复合体系可能加强蛋白质的疏水腔,使在水溶液中形成的疏水界面趋于集中,从而导致其共振光散射强度增强;体系受pH的影响变化非常灵敏;适当的NaCl浓度可以提高体系的I_(RLS)值灵敏度;共存离子改变了体系的离子强度,从而导致体系的△I_(RLS)值的改变;反应时间为5 min时,体系I_(RLS)值基本稳定;同一种表面活性剂对于不同的体系的I_(RLS)值的作用不完全一致,带相反电荷的表面活性剂与纳米复合物有很强的静电作用;对于与HSA相互作用的多元复合体系,加样顺序的不同对体系的I_(RLS)值的影响很明显;体系的I_(RLS)值随温度的改变呈不完全单调增加的趋势。这些信息为纳米材料与生物大分子的相互作用机制提供理论支撑,有助于深入了解纳米材料的生物相容性和安全性。     

Human cognitive paradigm and its application in semi-supervised learning

In many practical data mining applications such as web page classification, unlabeled training examples are readily available but labeled ones are fairly expensive to obtain. Therefore, semi-supervised learning algorithms such as Tri-training have attracted much attention. However, mislabeling the unlabeled data during the learning process is an inevitable problem and harms the performance improvement of the hypothesis. To solve this problem, a novel human cognitive paradigm is constructed for semi-supervised learning in this paper. In detail, based on local distribution of feature space, the majority voting scheme is substituted by an estimation of the probability of sample to belong to a certain class as an efficient strategy for data editing. It considers the form of the underlying probability distribution in the neighborhood of a point to identify and remove the mislabeled data. Validation of the proposed method is performed with extensive experiments. Results demonstrate that compared with Tri-training method, our method can more effectively and stably exploit unlabeled data to enhance the learning performance.