PID controller for automatic voltage regulator using teaching–learning based optimization technique

The present work presents teaching–learning based optimization (TLBO) algorithm as an optimization technique in the area of tuning of the classical controller installed in automatic voltage regulator (AVR). The proposed TLBO algorithm is applied with an aim to find out the optimum value of proportional integral derivative (PID) controller gains with first order low pass filter installed in the AVR. The voltage response of the AVR system, as obtained by using the proposed TLBO based PID controller with first order low pass filter, is compared to those offered by the other algorithms reported in the recent state-of-the-art literatures. The advantage of using this control strategy may be noted by providing good dynamic responses over a wide range of system parametric variations. For on-line, off-nominal operating conditions, fast acting Sugeno fuzzy logic technique is applied to obtain the on-line dynamic responses of the studied model. Furthermore, robustness analysis is also carried out to check the performance of the designed TLBO based PID controller. An analysis, based on voltage response profile, has been investigated with the variations of the model parameters. The simulation results show that the proposed TLBO based PID controller is a significant optimization tool in the subject area of the AVR system. The essence of the present work signifies that the proposed TLBO technique maybe, successfully, applied for the AVR of power system.     

Nanoparticle engineering processes for enhancing the dissolution rates of poorly water soluble drugs

Poor water solubility is an industry wide issue, especially for pharmaceutical scientists in drug discovery and drug development. In recent years, nanoparticle engineering processes have become promising approaches for the enhancement of dissolution rates of poorly water soluble drugs. Nanoparticle engineering enables manufacturing of poorly water soluble drugs into nanoparticles alone, or incorporation with a combination of pharmaceutical excipients. The use of these processes has dramatically improved in vitro dissolution rates and in vivo bioavailabilities of many poorly water soluble drugs. This review highlights several commercially or potentially commercially available nanoparticle engineering processes recently reported in the literature for increasing the dissolution properties of poorly water soluble drugs.     

球形聚焦电极系的k值和纵向分辨率

李清亮．球形聚焦电极系的ｋ值和纵向分辨率．测井技术，１９９５，１９（４）：２６７～２７０均质ｋ值主要取决于电极系尺寸。对其准确求解有助于电极系的设计与考察。本文利用更贴近实际的物理模型，精确求出了球形聚焦电极系的均质ｋ值。由微扰法得到的纵向几何因子，可对该电极系的纵向识别能力进行定量讨论。     

增强上下文的错误定位技术

错误定位就是寻找程序错误的位置.现有的错误定位方法大多利用测试用例的覆盖信息,以标识一组导致程序失效的可疑语句,却忽视了这些语句相互作用导致失效的上下文.因此,提出一种增强上下文的错误定位方法Context-FL,以构建上下文的方式来优化错误定位性能.Context-FL利用动态切片技术构建数据与控制相关性的错误传播上下文,显示了导致失效的语句之间传播依赖关系;然后,基于可疑值度量来区分上下文片段中不同语句的可疑度;最后,Context-FL以标记可疑值的上下文作为定位结果.实验结果表明,Context-FL优于8种典型错误定位方法.     

基于改进蛙跳算法的图像对比度增强方法

为改善图像对比度,提出了一种基于改进蛙跳算法的图像对比度增强新方法。该方法利用分段线性变换增强图像的原理,对蛙跳算法进行深入分析并进行改进后,将改进蛙跳算法与二维Otsu法相结合,利用蛙群的并行搜索机制自动选取图像的双阈值,然后再以图像的对比度作为改进蛙跳算法的适应度函数,自适应地搜索分段线性变换的斜率,并以之增强图像。实验结果表明,该方法有效改善原图像的对比度,且优于直方图均衡化法及基于基本蛙跳算法和人工鱼群算法的增强方法。     

《雪夜停林边》三个汉译本的人际功能分析

本文旨在从韩礼德的人际功能入手,围绕语气、情态、评价三个方面浅析弗罗斯特《雪夜停林边》一诗的三种汉译文,从中可以看出评价理论的介入使得人际功能在分析作者立场和观点方面更为重要,并验证了该模式在研究诗歌翻译中的可操作性和可应用性。     

Nanoparticle Engineering Processes for Enhancing the Dissolution Rates of Poorly Water Soluble Drugs

Poor water solubility is an industry wide issue, especially for pharmaceutical scientists in drug discovery and drug development. In recent years, nanoparticle engineering processes have become promising approaches for the enhancement of dissolution rates of poorly water soluble drugs. Nanoparticle engineering enables manufacturing of poorly water soluble drugs into nanoparticles alone, or incorporation with a combination of pharmaceutical excipients. The use of these processes has dramatically improved in vitro dissolution rates and in vivo bioavailabilities of many poorly water soluble drugs. This review highlights several commercially or potentially commercially available nanoparticle engineering processes recently reported in the literature for increasing the dissolution properties of poorly water soluble drugs.     

复杂媒质中聚焦电极系响应的快速算法

利用高效的数值模式匹配方法（NMM）求解二维轴对称介质的位场格林函数，并结合表面积分方程法来匹配球形聚焦电极系上复杂的激励条件，圆满地解决了复杂介质中位场的分析，其数值结果与文献数据相吻合。本文还讨论了无源等位体对球形聚焦电极系测井响应的影响。     

SFL系列浮子式量水堰仪电路改进设计

针对SFL系列浮子式量水堰仪在大坝安全监测工程实际应用中暴露出来的浪涌保护弱、防潮效果差、可靠性欠佳等问题进行电路改进,设计一款新型TS_485变送器。新型TS_485变送器基于STC15F2K60S2微处理器的微功耗平台,采用双通道、高分辨率的16位A/D电压采集,Modbus标准通讯协议的RS-485接口,4 kV/1A防雷和静电保护等,再通过专业的结构封装,与SFL系列浮子式量水堰仪内嵌成为智能一体化传感仪器。实验表明,满量程TS_485变送器的相对误差≤0.024%,重复性误差≤0.04%,迟滞性误差≤0.02%,长期稳定性误差≤0.02%,高温高湿环境中误差≤0.25%,能有效实现低功耗、高可靠性及防雷防潮等功能。     

基于网络邻域拓扑的粒子群优化算法

探讨类无标度网、全局耦合网、环形网、随机网、星形网等邻域拓扑结构对粒子群优化算法寻优效果的影响。理论分析与实验结果显示,以类无标度网作为邻域拓扑结构的粒子群优化算法在误差范围内的寻优效果最好,收敛速度最快,可以较好地避免陷入局部最优,且网络平均度对粒子群优化算法的寻优效果有一定的影响。