Diffusion-Based Path Planning in Mobile Actuator-Sensor Networks (MAS-Net): Some Preliminary Results Kevin L. Moore a , YangQuan Chen a , and Zhen Song a a CSOIS, Utah State University, Logan, UT, US ABSTRACT In this paper we present preliminary results related to path-planning problems when it is known that the quantities of interest in the system are generated via a diffusion process. The use of mobile sensor-actuator networks (MAS-Net) is proposed for such problems. A discussion of such networks is given, followed by a description of the general framework of the problem. Our strategy assumes that a network of mobile sensors can be commanded to collect samples of the distribution of interest. These samples are then used as constraints for a predictive model of the process. The predicted distribution from the model is then used to determine new sampling locations. A 2-D testbed for studying these ideas is described. The testbed includes a network of ten robots operating as a network using Intel Motes. We also present simulation results from our initial partial differential equation model of the diffusion process in the testbed. Key Words: Sensor networks, actuator networks, mobile actuator sensor networks (MAS-net), diffusion process characterization, mobility platform, mobile robots, diffusion-based path planning, PDE simulation. 1. INTRODUCTION In this paper and its companion (in this same meeting 1 ), we explore preliminary results and technical challenges, respectively, related to a concept initially proposed in. 2 Our concern in both 1 and 2 is the need for homeland security, which has been highlighted by recent terrorism events. Along with the need to develop security systems to prevent terrorist acts comes the need to respond to such acts, should they occur. From this perspective, a particular concern is the security of hazardous materials storage facilities and capabilities to respond to chemical-biological-radiological (CBR) terrorism aimed at such facilities. Indeed, it has been suggested that terrorists view CBR storage facilities as possible targets. As such, there is an interest in a system that could assess and track the plume that would result from an attack on such a facility, and its associated concentration, as illustrated in Figure 1. In 2 we proposed a unique, model-based approach aimed at this type of problem. The general system concept presented in that work is illustrated in Figure 2. Operationally, 1. A plume-generating event initiates deployment of the system. As shown, the idea is we have a small portable system of unmanned air vehicles (UAVs) that can be pre-staged or stored at fixed locations and which would be easily transported, deployed, operated, and maintained. 2. Using all possible data (such as weather information and information about the storage facility and the possible hazardous materials that have been released), the command and control system determines where sensor measurements should be made and directs the mobile sensors to appropriate locations. 3. The UAVs autonomously travel to the prescribed sampling locations within the plume, at which point sensors are used to assess the contamination hazards within the plume. 4. The sensor data is then transmitted to the ground station. 5. Using the up-to-date sensor data, the command and control system on the ground station updates its prediction of the plume location and then directs the UAVs to new sampling locations. Ground crew personnel would also relay this information to emergency management teams. Center for Self-Organizing and Intelligent Systems (CSOIS), Utah State University, 4160 Old Main Hill, Logan, UT 84322-4160. Phone/Fax: (435)797-2924/2003. Email: http://www.csois.usu.edu SPIE USE, V. 4 5421-8 (p.1 of 12) / Color: No / Format: Letter/ AF: Letter / Date: 2004-01-22 17:32:35 Please verify that (1) all pages are present, (2) all figures are acceptable, (3) all fonts and special characters are correct, and (4) all text and figures fit within the margin lines shown on this review document. Return to your MySPIE ToDo list and approve or disapprove this submission.