Group 1 - Beijing's winter ice and snow recreational venues, including Shichahai Ice Rink and Yuanmingyuan, have opened amid low temperatures, attracting large crowds [1][2] - The Shichahai Ice Rink features two ice surfaces with a total area of 70,000 square meters, becoming a popular destination during weekends and holidays [1] - The local police have implemented a "joint operation + precise control" mechanism to ensure safety, including pre-opening ice thickness checks and dynamic crowd management based on real-time visitor numbers [1][2] Group 2 - Haidian Public Security Bureau has adopted a tailored approach for each ice venue, integrating smart policing systems to monitor crowd density and ensure safety limits are maintained [2] - Traffic management measures have been established around key areas like Shichahai and military ski resorts, with dynamic adjustments to police deployment based on visitor flow [2] - The police have emphasized the importance of using regulated and well-protected ice venues, advising the public to avoid unregulated areas and to follow safety guidelines while enjoying the ice activities [3]