Electrical power systems are one of the most complex large scale systems. Over the past decades, with deregulation and increasing demand in many countries, power systems have been operated in a stressed condition and subject to higher risks of

在动物饲料市场上大豆和菜粕互帮互为替代品，为了研究用大豆主力期货为菜粕现货套期保值的功能，本文运用确定套期保值比率的OLS、VAR和ECM三个模型和套期保值绩效的衡量指标，对上述二者的套期保值比率和绩效进行了实证研究。结果显示，大豆主力期货和菜粕现货周数据的最佳套期保值比率是0.1338，套期保值绩效为0.0832。在本文中，从模型上看，ECM模型的套期保值比率和绩效比OLS和VAR模型要高，但利用样本数据所得的结果是OLS模型的套期保值比率和绩效比VAR和ECM模型要高。不过随着中国期货市场

tuning of pid controller for a higher order system by different tuing algorithms