Photo taken on May 7, 2021 shows the 20th Jinan International Security Defensive Production Exhibition held in Jinan City, eastern China's Shandong Province. Over 700 enterprises gathered at the expo to demonstrate products with such cutting-edge technologies as 5G communication, AI, Big Data and IoT applied, trying to address problems in the field of public security. (Hao Xincheng/Guangming Picture)

Photo taken on May 7, 2021 shows the 20th Jinan International Security Defensive Production Exhibition held in Jinan City, eastern China's Shandong Province. Over 700 enterprises gathered at the expo to demonstrate products with such cutting-edge technologies as 5G communication, AI, Big Data and IoT applied, trying to address problems in the field of public security. (Hao Xincheng/Guangming Picture)

Photo taken on May 7, 2021 shows the 20th Jinan International Security Defensive Production Exhibition held in Jinan City, eastern China's Shandong Province. Over 700 enterprises gathered at the expo to demonstrate products with such cutting-edge technologies as 5G communication, AI, Big Data and IoT applied, trying to address problems in the field of public security. (Hao Xincheng/Guangming Picture)

来源：GMW.cn