A new method for fault prediction of model-unknown nonlinear system

In this paper, the subspace identification based robust fault prediction method which combines optimal track control with adaptive neural network compensation is presented for prediction the fault of unknown nonlinear system. At first, the local approximate linear model based on input-output of unknown system is obtained by subspace identification. The optimal track control is adopted for the approximate model with some unknown uncertainties and external disturbances. An adaptive RBF neural network is added to the track control in order to guarantee the robust tracking ability of the observation system. The effect of the system nonlinearity and the error caused by subspace modeling can be overcome by adaptive tuning of the weights of the RBF neural network online without any requisition of constraint or matching conditions. The stability of the designed closed-loop system is thus proved. A density function estimation method based on state forecasting is then used to judge the fault. The proposed method is applied to fault prediction of model-unknown fighter F-8II of China airforce and the simulation results show that the proposed method can not only predict the fault, but has strong robustness against uncertainties and external disturbances.     

A perspective on optical developments in microfluidic platforms for Caenorhabditis elegans research

Microfluidics offers unique ways of handling and manipulating microorganisms, which has particularly benefited Caenorhabditis elegans research. Optics plays a major role in these microfluidic platforms, not only as a read-out for the biological systems of interest but also as a vehicle for applying perturbations to biological systems. Here, we describe different areas of research in C. elegans developmental biology and behavior neuroscience enabled by microfluidics combined with the optical components. In particular, we highlight the diversity of optical tools and methods in use and the strategies implemented in microfluidics to make the devices compatible with optical techniques. We also offer some thoughts on future challenges in adapting advancements in optics to microfluidic platforms.     

A multimodal query expansion based on genetic programming for visually-oriented e-commerce applications

We present a novel multimodal query expansion strategy, based on genetic programming (GP), for image search in visually-oriented e-commerce applications. Our GP-based approach aims at both: learning to expand queries with multimodal information and learning to compute the “best” ranking for the expanded queries. However, different from previous work, the query is only expressed in terms of the visual content, which brings several challenges for this type of application. In order to evaluate the effectiveness of our method, we have collected two datasets containing images of clothing products taken from different online shops. Experimental results indicate that our method is an effective alternative for improving the quality of image search results when compared to a genetic programming system based only on visual information. Our method can achieve gains varying from 10.8% against the strongest learning-to-rank baseline to 54% against an adhoc specialized solution for the particular domain at hand.     

基于支持向量机的外贸出口预测

针对支持向量机(SVM)方法所具有的拟合精度高、推广能力强、全局最优且针对小样本等特点,本文将SVM回归建模方法引入到外贸出口预测中,对出口时间序列建立预测模型,并利用此法对重庆摩托车出口进行了预测,对其预测性能进行了验证比较。结果表明,SVM方法对非平稳的小样本出口时间序列数据有良好的建模和泛化能力,且可达到较高的预测精度。     

组织中知识生产的知识服务平台分析

知识生产可以为组织创造新知识,提高组织的应变力和创新力。高效率的知识生产和创新是组织维持竞争优势的前提。然而高效的知识生产和知识创新需要一个良好的服务平台,以满足知识服务业发展要求和提高知识生产效率为出发点,为知识生产提供了两种服务平台,即知识生产服务模型"硬件"平台和知识生产"软件"平台。其中,"硬件"平台是由基于知识网格的六层结构模型构成,它能使网格内所有成员有效地共享和利用网格内的资源;"软件"平台对"硬件"平台起重要作用,它使整个知识服务平台能更加和谐高效地运行。     

无线Ad Hoc网络中一种网络无关的P2P流媒体优化传输方案

根据无线Ad Hoc网络环境下P2P流媒体数据传输的特点,提出一种工作在P2P数据拓扑层面的,不依赖于底层物理网络的节点配置和特定的路由算法的优化传输方案.在发送数据时,节点结合应用层视频分片的重要性和网络状况动态地调整传输层参数,从而减小重要数据的传输延时和播放超时的概率.仿真结果验证了本方案对于改善服务质量和减小控制信令开销的有效性.     

A three-phase method for patent classification

An automatic patent categorization system would be invaluable to individual inventors and patent attorneys, saving them time and effort by quickly identifying conflicts with existing patents. In recent years, it has become more and more common to classify all patent documents using the International Patent Classification (IPC), a complex hierarchical classification system comprised of eight sections, 128 classes, 648 subclasses, about 7200 main groups, and approximately 72,000 subgroups. So far, however, no patent categorization method has been developed that can classify patents down to the subgroup level (the bottom level of the IPC). Therefore, this paper presents a novel categorization method, the three phase categorization (TPC) algorithm, which classifies patents down to the subgroup level with reasonable accuracy. The experimental results for the TPC algorithm, using the WIPO-alpha collection, indicate that our classification method can achieve 36.07% accuracy at the subgroup level. This is approximately a 25,764-fold improvement over a random guess.     

A method for reducing pressure-induced deformation in silicone microfluidics

Poly(dimethylsiloxane) or PDMS is an excellent material for replica molding, widely used in microfluidics research. Its low elastic modulus, or high deformability, assists its release from challenging molds, such as those with high feature density, high aspect ratios, and even negative sidewalls. However, owing to the same properties, PDMS-based microfluidic devices stretch and change shape when fluid is pushed or pulled through them. This paper shows how severe this change can be and gives a simple method for limiting this change that sacrifices few of the desirable characteristics of PDMS. A thin layer of PDMS between two rigid glass substrates is shown to drastically reduce pressure-induced shape changes while preserving deformability during mold separation and gas permeability.     

企业知识资本评估新方法探析--标杆瞄准评估法

本文在总结了企业知识资本评估方法的基础上,提出了一种全新的企业知识资本评估方法,即标杆瞄准评估法。该方法立足于企业之间的对比分析,更易于企业的应用。     

A mechanical method for graphical solution of polynomials

A mechanical synthesizer with thirty harmonic elements (fifteen sine components and fifteen cosine components) may be used to graph a polynomial in a complex plane. The sum of the sine components is recorded by a tracing point which moves vertically. The sum of the cosine components is recorded by horizontal motion of a drawing board.     

A two-step iterative method for discrete-time systems reduction

A two-step iterative method (1,2) for a reduction in the order of linear continuous-time systems, given in the state equation or the transfer function, is extended to reduce discrete-time systems. The method requires the optimization of the residues and eigenvalues (or poles) belonging to an objective function. The objective function to be minimized is chosen as the finite sum of the squares of the error between the step responses of the reduced model and the original system. This scheme is continued cyclically until the objective function is satisfactorily minimized. By investigating the initial selection of the eigenvalues in the reduced-order model, it is found that the dominant eigenvalues of the original system give a good approximation. Further, the resulting model is always stable, assuming the original system is stable. As shown in a numerical example, the proposed method is superior to the other methods of model reduction in both steady-state and transient responses, and in the value of the sum of the squares of the error.     

A fast BER evaluation method for LDGM codes

Low-density generator matrix (LDGM) codes have recently drawn researchers’ attention thanks to their satisfying performance while requiring only moderate encoding/decoding complexities as well as to their applicability to network codes. In this paper, we aim to propose a fast simulation method useful to investigate the performance of LDGM code. Supported by the confidence interval analysis, the presented method is, for example, 10⁸ times quicker than the Monte-Carlo computer simulation for bit-error-rate (BER) in 10⁻¹⁰ region.