# Networking for Cloud Robotics: The DewROS Platform and Its Application
## 1 Introduction  
Cloud Robotics aims to create a new generation of robots, in which at least some of the resources, in terms of computing, memory, and storage, are provided by external Data Centers (i.e., in Cloud). At present, robotic systems are generally equipped with an increasing number of sensing units to make them increasingly autonomous. Processing the data from such sensors can be very resource-demanding [1] (e.g., for the analysis of high-resolution videos captured by the HD cameras). The Cloud can then be used to offload these heavy tasks. The wide availability of computational and storage resources appears to be almost unlimited. Additionally, the necessary management effort for provision is minimal. For these reasons, Cloud is a very beneficial addition to the Robotics field. However, some tasks cannot be offloaded because of elements such as timing requirements (i.e., tasks that operate on a milli- or microsecond time scale). Distributed solutions are, therefore, necessary where the computation and storage are spread among the robot, the network device close to it, and the Cloud. This architecture has been recently proposed under the term Dew Robotics [2]. In this paper, we present a platform for Dew Robotics based on ROS [3], the most spread software environment for robots, and called DewROS. We first present its design and implementation. After this, we concentrate on the application of DewROS in a real use-case, in the context of a European Project called SHERPA [4, 5]. This project aims to develop a mixed-ground and aerial robotic platform for Search and Rescue (SAR) operations inalpine environments. In this context, a human operator collaborates with a heterogeneous robotic system to rescue survivor victims after avalanches. The robotic team is composed of unmanned aerial vehicles (UAVs) with different characteristics and equipped with different types of sensor, in order to retrieve information from the rescue scene and assist the rescuer during a mission. Moreover, slowly moving robots called rover are also part of the team and occupy a central position in the team topology. Thanks to DewROS, we enabled the in-Cloud storage and processing of high-resolution images and videos captured by Unmanned Aerial Vehicles (UAVs) for the automatic detection of interesting situations such as landslides and the presence of living beings in certain areas. Before discussing DewROS framework, we briefly report the results of our previous work on Cloud Robotics in hazardous environments (see [5]), in which different network technologies are analyzed to define those most suitable for Cloud Robotics in a remote and hostile environment. In this previous paper, we introduced the possibility of using Cloud Computing for the Sherpa project. In this work, we take a step forward by designing a system that can realize this vision, and we test it with real Cloud services according to the Dew Robotics vision. In particular, in this paper, we report on the design, implementation, and testing of DewROS in a controlled environment. After this, a real application is introduced. In particular, a large experimental campaign using different Internet access technologies is presented, including a real satellite one, and two real Cloud services. For this scope, more than 600 annotation video labeling experiments were performed with Google Cloud Video Intelligence service and Amazon Recognition; videos with different characteristics such as the video location, size, length, label detection mode, etc., were considered. The goal of this study is to identify the aspects that have the smallest and the largest impact on the performance of the Cloud Robotics system. For example, this study demonstrates that the video duration has a much smaller impact with respect to the video size: videos with a duration up to about 70 s can be analyzed in a comparable time to videos of 3 s. Fixing the duration and doubling the video size can almost double the processing time.