Computer Languages and Systems Department, Universitat Jaume I (UJI), 12071 Castelló de la Plana, Spain.
Computer Science and Engineering Department, Universitat Jaume I (UJI), 12071 Castelló de la Plana, Spain.
Sensors (Basel). 2021 Mar 17;21(6):2116. doi: 10.3390/s21062116.
Riding a bicycle is a great manner to contribute to the preservation of our ecosystem. Cycling helps to reduce air pollution and traffic congestion, and so, it is one of the simplest ways to lower the environmental footprint of people. However, the cohabitation of cars and vulnerable road users, such as bikes, scooters, or pedestrians, is prone to cause accidents with serious consequences. In this context, technological solutions are sought that enable the generation of alerts to prevent these accidents, thereby promoting a safer city for these road users, and a cleaner environment. Alert systems based on smartphones can alleviate these situations since nearly all people carry such a device while traveling. In this work, we test the suitability of a smartphone based alert system, determining the most adequate communications architecture. Two protocols have been designed to send position and alert messages to/from a centralized server over 4G cellular networks. One of the protocols is implemented using a REST architecture on top of the HTTP protocol, and the other one is implemented over the UDP protocol. We show that the proposed alarm system is feasible regarding communication response time, and we conclude that the application should be implemented over the UDP protocol, as response times are about three times better than for the REST implementation. We tested the applications in real deployments, finding that drivers are warned of the presence of bicycles when closer than 150 m, having enough time to pay attention to the situation and drive more carefully to avoid a collision.
骑自行车是为保护我们的生态系统做出贡献的好方法。骑自行车有助于减少空气污染和交通拥堵，因此，这是降低人们环境足迹的最简单方法之一。然而，汽车和脆弱的道路使用者（如自行车、滑板车或行人）共存容易导致事故，造成严重后果。在这种情况下，人们寻求技术解决方案，以生成警报来预防这些事故，从而为这些道路使用者提供更安全的城市和更清洁的环境。基于智能手机的警报系统可以缓解这些情况，因为几乎所有人在旅行时都携带这样的设备。在这项工作中，我们测试了基于智能手机的警报系统的适用性，确定了最合适的通信架构。已经设计了两种协议，用于通过 4G 蜂窝网络将位置和警报消息发送到/从中央服务器。其中一个协议是在 HTTP 协议之上使用基于 REST 的架构实现的，另一个协议是通过 UDP 协议实现的。我们表明，所提出的报警系统在通信响应时间方面是可行的，并且我们得出结论，应用程序应该通过 UDP 协议实现，因为响应时间比 REST 实现快大约三倍。我们在实际部署中测试了这些应用程序，发现当距离自行车 150 米以内时，驾驶员会收到自行车存在的警报，有足够的时间注意到情况并更加小心地驾驶以避免碰撞。
