水利对粮食生产贡献率的认识与思考

针对目前很多人对农业科技进步贡献率和水利对粮食生产贡献率的不同认识,从发展历程、概念内涵、测算思路方法等方面,剖析了二者差异,认为二者在测算范围上存在大口径与小口径的差异,在测算对象上存在增量与总量的差异,在测算指标上存在产值与产量的差异,在测算方法上存在余值法与有无对比法的差异,为正确认识这两个指标提供了参考。     

基于弹性盒子模型的跨平台手机应用界面布局

针对目前手机应用程序普遍存在的平台单一、界面布局难、适配程度不高等问题,提出一种基于弹性盒子模型的跨平台手机应用界面布局方法,并用基于HTML 5的跨平台开发框架AppCan实现一个典型页面的弹性布局,得到了较好的布局效果。     

Acoustic emission from gas-filled coal under triaxial compression

Acoustic emission (AE) experiments have been performed on gas-saturated coal specimens under conventional triaxial compression. The AE characteristics were investigated for a methane gas flow through the coal specimen. One AE parameter, AE count, when normalized by the total count number was used to represent the damage evolution in the gassy coal. It is shown that this AE parameter is a reasonable indicator for damage occurring within the coal specimen since its envelope has almost the same shape as the complete stress–strain curve, except for a short time delay. In addition, the change in AE count is highly consistent with the change in coal permeability. Test results also show that methane containing coal emits a small number of AE events before entering the yield stage. AE activity gradually increases during the yield process up to the peak stress. The lowest permeability corresponds to the highest AE activity, implying failure will soon occur. An AE based constitutive model was constructed and the theoretical results agree well with those of experiments.     

SVD-based Preisach hysteresis identification and composite control of piezo actuators

In this paper, the singular value decomposition (SVD) based identification and compensation of the hysteretic phenomenon in piezo actuators are addressed using a Preisach model. First, this paper presents an SVD-based least squares algorithm and a revision approach of the identification through updating the SVD. With the identified parameters and a log of the memory curve, a Preisach-based inversion compensator is constructed which is complemented with a feedback controller to address the inevitable and residual modeling errors. Experimental results are furnished for both the identification and compensation approaches. The Preisach-based feedforward controller significantly improves the tracking performance and reduces the root-mean-square (RMS) tracking error of a PID controller by 76.7% and 89% at 1 Hz and 25 Hz, respectively. With the proposed composite controller, the percent-RMS errors at 1 Hz and 25 Hz are reduced to 0.035% and 0.31%, respectively.     

Robust and efficient ridge-based palmprint matching

During the past decade, many efforts have been made to use palmprints as a biometric modality. However, most of the existing palmprint recognition systems are based on encoding and matching creases, which are not as reliable as ridges. This affects the use of palmprints in large-scale person identification applications where the biometric modality needs to be distinctive as well as insensitive to changes in age and skin conditions. Recently, several ridge-based palmprint matching algorithms have been proposed to fill the gap. Major contributions of these systems include reliable orientation field estimation in the presence of creases and the use of multiple features in matching, while the matching algorithms adopted in these systems simply follow the matching algorithms for fingerprints. However, palmprints differ from fingerprints in several aspects: 1) Palmprints are much larger and thus contain a large number of minutiae, 2) palms are more deformable than fingertips, and 3) the quality and discrimination power of different regions in palmprints vary significantly. As a result, these matchers are unable to appropriately handle the distortion and noise, despite heavy computational cost. Motivated by the matching strategies of human palmprint experts, we developed a novel palmprint recognition system. The main contributions are as follows: 1) Statistics of major features in palmprints are quantitatively studied, 2) a segment-based matching and fusion algorithm is proposed to deal with the skin distortion and the varying discrimination power of different palmprint regions, and 3) to reduce the computational complexity, an orientation field-based registration algorithm is designed for registering the palmprints into the same coordinate system before matching and a cascade filter is built to reject the nonmated gallery palmprints in early stage. The proposed matcher is tested by matching 840 query palmprints against a gallery set of 13,736 palmprints. Experimental results show that the proposed matcher outperforms the existing matchers a lot both in matching accuracy and speed.     

Identification of Breast Cancer Prognosis Markers via Integrative Analysis

In breast cancer research, it is of great interest to identify genomic markers associated with prognosis. Multiple gene profiling studies have been conducted for such a purpose. Genomic markers identified from the analysis of single datasets often do not have satisfactory reproducibility. Among the multiple possible reasons, the most important one is the small sample sizes of individual studies. A cost-effective solution is to pool data from multiple comparable studies and conduct integrative analysis. In this study, we collect four breast cancer prognosis studies with gene expression measurements. We describe the relationship between prognosis and gene expressions using the accelerated failure time (AFT) models. We adopt a 2-norm group bridge penalization approach for marker identification. This integrative analysis approach can effectively identify markers with consistent effects across multiple datasets and naturally accommodate the heterogeneity among studies. Statistical and simulation studies demonstrate satisfactory performance of this approach. Breast cancer prognosis markers identified using this approach have sound biological implications and satisfactory prediction performance.     

关于复正规矩阵的Rayleigh商

将Hermite矩阵的Rayleigh商推广到了复正规矩阵中,研究了复正规矩阵的Ray-leigh商的一些性质,其结果具有一定的理论价值和应用价值。     

模糊综合评价法在长江下游贵池河段水质评价中的应用

对水质评价存在诸多方法,而模糊综合评价法具有评价结果合理、更接近客观实际等优点,因而得到越来越广泛的应用。通过模糊评价方法对长江下游贵池河段2005～2009年间水环境综合评价,并采用加权平均原则求取隶属等级,取得较好的效果。     

城市设计中的文化因素对城市发展的影响研究

在城市设计过程中,突出城市的个性化文化元素是必不可少的,城市文化的再生也已成为促进城市积极发展的主要方法之一。本文着眼于文化对城市发展的影响以及城市设计理论与文化再生之间的相互关系,分析了文化在城市发展过程中扮演的角色与所起的作用,城市的蓬勃发展离不开其文化属性的凸显,有助于特色文化城市的形成。     

ZigBee在动态血压监测中的应用研究

我国已成为世界上高血压危害最严重的国家之一,在全国范围大力开展高血压病的防治,积极治疗高血压病患者,已经刻不容缓.通过研究ZigBee技术,提出了以ZigBee无线传感器网络为核心,以以太网为骨干网,采用CC2430芯片为血压传感器控制核心的动态血压测量方案,系统测量的收缩压、舒张压误差范围均小于5mmHg.试验证明,系统能够实时监测患者的血压变化,工作稳定可靠,具有较高的实用性和市场价值.