程序挖掘的用户需求获取与分解

随着基于构件的程序挖掘思想[1]的提出，如何正确获取用户需求的描述成为程序挖掘中关键的第一步。本文在分析需求描述在程序挖掘中的特性的基础上，分析需求描述语言的发展，提出一种基于UML的用户需求描述语言，给出其XML描述形式，并结合我们自己定义的通用构件接口，研究需求分解的策略，具体给出需求分解算法，需求分解结果与通用构件接口之间的映射算法等。     

Multi‐color LC/BL algorithm in field‐sequential‐color LCD for color‐breakup suppression

Abstract— The proposed liquid‐crystal and backlight (LC/BL) algorithm presents the dynamic field‐sequential‐color (D‐FSC) algorithm to reduce the color‐breakup (CBU) effect without greatly increasing the subframe rate. The D‐FSC algorithm can intelligently select one adequate color sequence from multiple color sequences according to the image data. In other words, the scope of CBU suppression of the proposed LC/BL algorithm is more extensive than other conventional FSCs. Simulation results show that the CBU suppression can be improved substantially by the proposed evaluation equation.     

Periodic peristalsis enhancing the high solids enzymatic hydrolysis performance of steam exploded corn stover biomass

Enzymatic hydrolysis beyond 15% solid loading offers many advantages such as increased sugar and ethanol concentrations and decreased capital cost. However, difficult mixing and handling limited its industrialized application. A novel intensification method, periodic peristalsis, had been exploited to improve the high solids enzymatic hydrolysis performance of steam exploded corn stover (SECS). The optimal steam explosion conditions were 200 °C and 8 min, under which glucan and xylan recovery was 94.3% and 64.8%, respectively. Glucan and xylan conversions in periodic peristalsis enzymatic hydrolysis (PPEH) were 28.0–38.5% and 25.0–36.0% higher than those in static state enzymatic hydrolysis with solid loading increasing from 1% to 30%, respectively, while they were 1.0–11.2% and 3.0–9.2% higher than those in incubator shaker enzymatic hydrolysis (ISEH). Glucan and xylan conversion in PPEH at 21% solid loading reached 71.2% and 70.3%, respectively. Periodic peristalsis also facilitated fed-batch enzymatic hydrolysis of which SECS was added completely before transition point. Results presented that PPEH shortened the transition point time from solid state to slurry state, decreased the viscosity of hydrolysis mixture, and reduced the denaturation effect of enzymes compared with ISEH, and hence improve the high solids enzymatic hydrolysis efficiency.     

Reduced power consumption compared to a traditional stirred tank reactor (STR) for enzymatic saccharification of alpha-cellulose using oscillatory baffled reactor (OBR) technology

Enzymatic saccharification of pure α-cellulose was conducted in oscillatory baffled (OBR) and stirred tank (STR) reactors over a range of mixing intensities requiring power densities (P/V) from 0 to 250 Watts per cubic metre (W/m³). Both reactor designs produced similar saccharification conversion rates at zero mixing. Conversion increased with increasing mixing intensity. The maximum conversion rate occurred at an oscillatory Reynolds number (Re_o) of 600 in the OBR and at an impeller speed of between 185 and 350 rpm in the STR. The OBR was able to achieve a maximum conversion rate at a much lower power density (2.36 W/m³) than the STR (37.2–250 W/m³). The OBR demonstrated a 94–99% decrease in the required power density to achieve maximum conversion rates and showed a 12% increase in glucose production after 24 h at 2.36 W/m³.     

基于社区的动态网络节点介数中心度更新算法

随着互联网技术的迅猛发展,社会网络呈现出爆炸增长的趋势,传统的静态网络分析方法越来越难以达到令人满意的效果,于是对网络进行动态分析就成为社会网数据管理领域的一个研究热点。节点介数中心度衡量的是一个节点对图中其他点对最短路径的控制能力,有利于挖掘社会网络中的重要节点。在图结构频繁变化的场合,若每次变化后都重新计算整个图中所有节点的介数中心度,则效率将会很低。针对动态网络中节点介数中心度计算困难的问题,本文提出一种基于社区的节点介数中心度更新算法。通过维护社区与社区、社区与节点的最短距离集合,快速过滤掉那些在网络动态更新中不受影响的点对,从而大大提高节点介数中心度的更新效率。真实数据集和合成数据集上的实验结果表明了论文所提算法的有效性。