Today safety has become an important eld and its history in the modern times may be traced back to 1868 when a patent was awarded for the rst barrier safeguard in the United States [1]. In 1893, the United States Congress passed the Railway Safety Act and, in 1912, the cooperative Safety Congress met for the rst time in Milwaukee, Wisconsin [1,2]. Nowadays, the eld of safety has developed into many areas including medical equipment safety, software safety, transportation systems safety, and robot safety.