Option Momentum

This paper investigates the performance of option investments across different stocks by computing monthly returns on at-the-money straddles on individual equities. We find that options with high historical returns continue to significantly outperform options with low historical returns over horizons ranging from 6 to 36 months. This phenomenon is robust to including out-of-the-money options or delta-hedging the returns. Unlike stock momentum, option return continuation is not followed by long-run reversal. Significant returns remain after factor risk adjustment and after controlling for implied volatility and other characteristics. Across stocks, trading costs are unrelated to the magnitude of momentum profits.     

从汶川地震通信问题谈平流层应急通信的应用

汶川地震暴露了我国应急通信系统不能满足突发事件通信需求,必须研究新型应急通信技术以克服当前应急通信存在的问题.提出了一种应用平流层通信技术实现应急通信系统的方法:在由飞艇组成的高空航空平台上装载基于微波技术的应急指挥通信系统和蜂窝移动基站,应急指挥通信系统用于突发事件的指挥通信,蜂窝移动通信用于公众通信.分析表明,平流层应急通信系统符合应急通信需求,具有部署快、成本低、容量大等特点.