Syrian President Bashar al-Assad offered an amnesty on Thursday for rebels who lay down their arms and surrender to authorities within three months.The amnesty offer, announced on state media, came as pro-government forces tightened their control around rebel-held districts of the northern city of Aleppo, where at least 250,000 civilians are believed to be trapped.Russia, which is supporting Assad, said on Thursday three corridors would be established by the Russian and Syrian militaries for civilians to leave the city. With the instability of the situation in Syria, the security situation become more and more serious.We should consider the situation of the continued violence in how we protect people and police safety problem.The Zhengyang rapid deployment barrier is mainly used for crowd control,riot prevention,prisoner short term detention ,site security,augmented fence perimeter security,and quick site security protection.