Optical fiber sensor for mine safety Internet of things oleh LIU Tongyu, WANG Jiqiang, MENG Xiangjun, LI Wei, JIN Guangxian, HU Jie, WEI Yubin, WANG Zhenping, HU Binxin, SONG Guangdong, MA Junpeng, WANG Jinyu, SONG Chengxiang, ZHANG Tingting, LI Yanfang, WANG Fengxue