A stochastic realization algorithm via block LQ decomposition in Hilbert space

A stochastic realization problem of a stationary stochastic process is re-visited, and a new stochastically balanced realization algorithm is derived in a Hilbert space generated by second-order stationary processes. The present algorithm computes a stochastically balanced realization by means of the singular value decomposition of a weighted block Hankel matrix derived by a “block LQ decomposition”. Extension to a stochastic subspace identification method explains how the proposed abstract algorithm is implemented in system identification.     

基于奇异值分解和神经网络的个性化信息模式识别

随着信息资源的持续增长，信息获取系统为特定用户提供特定信息服务的需求越来越重要。该文提出了基于奇异值分解和神经网络的个性化信息模式识别的方法，可以方便地获取用户信息需求的特征，并且利用这些特征信息完成个性化的信息识别和匹配，即实现个性化信息的模式识别，进而实现信息的个性化获取和管理。该文中的算法实现简单，可以方便地应用到目前的一些信息管理、服务系统中。     

中国硬质合金工业现状及发展趋势

简要总结了中国硬质合金工业所取得的成就及与国外先进水平比较存在的差距,并对国内外硬质合金市场和技术发展趋势进行了分析。     

非透视3点问题的解析解

由于在机器人导航等领域新的图像装置不符合透视规则,无法运用传统的透视位置估计方法,采用吴氏零点分解方法,给出非透视3点问题的解析解.利用新图像装置的几何条件,建立了非透视3点方程系统.     

东江水库诱发地震探讨

阐述了东江水库基本情况，通过对库区及周围的地质构造特点、诱发地震监测，总结出东江水库地震的活动特征和诱发地震活动趋势。     

水力喷砂割缝增产增注技术的作用原理及展望

本文对从俄罗斯引进的水力喷砂割缝技术的发展过程、工作原理及该技术在大庆油田的试验情况做了详细的阐述。并对它的改进及其将来的推广与发展前景做了展望。     

蒸汽压法测定导热油热分解温度的研究

根据克拉贝龙—克劳修斯方程，建立了国内外文献未见报道的测定导热油热分解温度的试验装置和试验方法，测定了大量国内外导热油的热分解温度，数据表明该法具有准确、简单、实用、省时、省力等优点     

Catalytic decomposition of HCFC22 (CHClF2)

The catalytic decomposition of CHClF₂ was studied over various acidic metal oxides in a fixed-bed reactor. The Cr₂O₃ZrO₂ exhibited the highest activity. The presence of water vapor in the reaction system suppresses the transformation of oxides to fluorides, progresses the formation of CO₂, and it improves the catalysts life.     

Trends in Hydrological Parameters of a Southern Brazilian Watershed and its Relation to Human Induced Changes

The Piracicaba river basin is a subtropical watershed located in the southeastern region of Brazil. With an area of 12 400 km², the basin is a typical example of new landscape resulting from development in tropical and sub-tropical regions: establishment of intensive industrial and agricultural processes were followed by significant population growth and water management. This scenario has led to significant increase in water demand and decrease in water quality. The main objective of this study is the detection of changes in the patterns of flow and precipitation in the basin, and its possible relation to man-induced changes. Statistical analyses were performed on records of precipitation, evapotranspiration and streamflow, from 1947 to 1991. Precipitation and evapotranspiration totals showed significant increasing trends for the entire basin. From eight streamflow gauge stations, half showed significant decreasing trend. The most probable cause of such trends is the export of water from the basin to the metropolitan region of São Paulo city.