基于Agent的面向DSS的模型库系统研究

智能性是决策支持系统未来的发展方向,为了提高决策支持系统模型库的智能性,文章将Agent的智能性融人到模型库系统中,提出了一种基于Agent的模型库系统构建方案。主要研究基于Agent的模型表示、模型选择和模型组合技术,模型库系统的架构方案及各功能Agent模型,详细阐述了模型库系统各部分的工作原理,并在JADE平台完成了模型库系统原型的开发。实验证明：所设计的基于Agent的模型库系统能很好的解决模型表示、模型组合和模型选择问题,比传统模型库系统具有更高的智能性。     

Application of enhanced cluster validity index function to automatic stock portfolio selection system

This paper presents an automatic stock portfolio selection system. In the proposed approach, 53 financial indices are collected for each stock item and are consolidated into six financial ratios [Grey relational grades (GRGs)] using a Grey relational analysis model. The GRGs are processed using a modified form of the PBMF index method (designated as the Huang index function) to determine the optimal number of clusters per GRG. The resulting cluster indices are then processed using rough set theory to identify the stocks within the lower approximate sets. Finally, the GRGs of each stock item in the lower approximate sets are consolidated into a single GRG, indicating the ability of the stock item to maximize the rate of return. It is demonstrated that the proposed stock selection mechanism yields a higher rate of return than several existing portfolio selection systems.     

基于伪反馈的XML查询扩展

伪反馈一直以来都被认为是一种有效的查询扩展技术.但是近来的研究表明传统的伪反馈容易带来主题漂移并因此而影响检索性能.如何确定相关文档以及如何从相关文档中挑选有用的扩展词项是伪反馈中两个重要的方面.与传统查询扩展不同,XML查询扩展不仅需要内容扩展还需要考虑结构扩展.提出了一个解决框架,利用聚类和词组抽取技术来查找相关文档和选择有用的扩展信息.结合XML的语义特征,提出了一种全新的基于层次信息的文档相似性度量方案.基于此,将初始检索结果聚类,获得与查询请求最为相关的文档簇,然后在文档簇中抽取词组,找到符合用户查询意图的扩展查询词组,并在扩展查询词组的基础上进行结构扩展,最终形成完整的"内容+结构"的查询扩展表达式.IEEE CS实验数据上的实验结果表明,结合了聚类和抽取技术的XML伪反馈查询扩展方法能有效地降低主题漂移现象,获得更好的检索质量.     

金刚石与石墨局域态密度和能带结构的第一原理分析

计算与分析电子结构对类金刚石薄膜材料的研究尤为重要.本文用第一原理分子动力学模拟,以研究金刚石和石墨的局域态密度和能带结构.第一原理计算赝势平面波法和密度泛函理论(DFT)去计算,电子交换相关能采用广义梯度近似(GGA)去描述,这种方法可以正确无误的预测半导体带隙与尺寸的关系.金刚石的禁带很宽,为绝缘体,Sp3杂化轨道在费米能级附近提供部分能态密度.石墨是零带隙半金属的内部结构根源就在于离域π键,费米能级处的能态密度几乎全部来自p能级的贡献.研究结果预测,结构变化和Sp杂化轨道产生的函数关系,是很多物理性质不同的最根本原因,而物理性质的研究则可以最直观的体现这种函数关系,可以更深入地研究金刚石和石墨这两种物质.     

电离层垂测仪系统信号源设计与实现

为了克服传统电离层垂测仪射频信号软件延时的缺点,提高大气电离层垂测仪系统信号源产生信号的精度,更充分地研究电离层物理特性,利用DDS技术和嵌入μC/OS-Ⅱ操作系统的miniARM微处理器,给出了一个新型的电离层垂测仪系统信号源的架构方案;该系统利用了32位ARM嵌入式微处理器LPC2220的定时器匹配硬件功能,控制DDS芯片Q2368完成无延时的相位调制;实验结果表明,该信号源所产生的高频信号具有精度高,频率转换时间短等特点,其他信号也完全满足电离层垂测仪对信号源的技术要求.     

Besov空间的阈值收缩和边缘补偿的图像去噪

提出一种新的图像去噪方法,它是Besov空间的变分模型,在负实数次Sobolev空间上定义了数据项,用Besov半范数定义了正则项。并详细推导了变分模型在Besov空间的阈值求解公式,先做一个Contourlet变换域的小阈值收缩,然后再利用该模型去噪。去除噪声的同时也损失了部分边缘信息,把边缘分为四种情况,针对不同情况确定相应的边缘补偿方法。实验表明该模型具有良好的去噪效果。     

Comparison of forecasting methods with an application to predicting excess equity premium

This paper reviews various forecast methods including combination using theoretically optimal weights and those under model selection approaches. In addition, we suggest two modified simple averaging forecast combination methods—a mean corrected and a mean and scale corrected method. We conclude that due to the fact that real data is usually subject to structural breaks, rolling forecasting scheme has a better performance than fixed window and continuously updating scheme. In addition, methods that use less information appear to perform better than methods using all the sample information about the covariance structure of the available forecasts. The mean and scale corrected simple average approach yield smaller mean squared forecast error than the three widely used regression approaches suggested by Granger and Ramanathan [11].     

Label-free Growth Receptor-2 Detection and Dissociation Constant Assessment in Diluted Human Serum Using a Longitudinal Extension Mode of a Piezoelectric Microcantilever Sensor

We have investigated real-time, label-free, in-situ detection of human epidermal growth factor receptor 2 (Her2) in diluted serum using the first longitudinal extension mode of a lead zirconate-lead titanate (PZT)/glass piezoelectric microcantilever sensor (PEMS) with H3 single-chain variable fragment (scFv) immobilized on the 3-mercaptopropyltrimethoxysilane (MPS) insulation layer of the PEMS surface. We showed that with the longitudinal extension mode, the PZT/glass PEMS consisting of a 1 mm long and 127 μm thick PZT layer bonded with a 75 μm thick glass layer with a 1.8 mm long glass tip could detect Her2 at a concentration of 6-60 ng/ml (or 0.06-0.6 nM) in diluted human serum, about 100 times lower than the concentration limit obtained using the lower-frequency flexural mode of a similar PZT/glass PEMS. We further showed that with the longitudinal mode, the PZT/glass PEMS determined the equilibrium H3-Her2 dissociation constant K(d) to be 3.3±0.3 × 10(-8) M consistent with the value, 3.2±0.28 ×10(-8) M deduced by the surface plasmon resonance method (BIAcore).     

Autonomous topological modeling of a home environment and topological localization using a sonar grid map

This paper presents a method of autonomous topological modeling and localization in a home environment using only low-cost sonar sensors. The topological model is extracted from a grid map using cell decomposition and normalized graph cut. The autonomous topological modeling involves the incremental extraction of a subregion without predefining the number of subregions. A method of topological localization based on this topological model is proposed wherein a current local grid map is compared with the original grid map. The localization is accomplished by obtaining a node probability from a relative motion model and rotational invariant grid-map matching. The proposed method extracts a well-structured topological model of the environment, and the localization provides reliable node probability even when presented with sparse and uncertain sonar data. Experimental results demonstrate the performance of the proposed topological modeling and localization in a real home environment.     

A neural network approach for solving mathematical programs with equilibrium constraints

A neural network approach is presented for solving mathematical programs with equilibrium constraints (MPEC). The proposed neural network is proved to be Lyapunov stable and capable of generating approximal optimal solution to the MPEC problem. The asymptotic properties of the neural network are analyzed and the condition for asymptotic stability, solution feasibility and solution optimality are derived and the transient behavior of the neural network is simulated and the validity of the network is verified with numerical examples.