Challenges and Solutions for Location-based Routing in Wireless Sensor Networks with Complex Network Topology

Complex Network Topologies (CNTs)–network holes and cuts–often occur in practical WSN deployments. Many researchers have acknowledged that CNTs adversely affect the performance of location-based routing and proposed various CNT- aware location-based routing protocols. However, although they aim to address practical issues caused by CNTs, many proposed protocols are either based on idealistic assumptions, require too much resources, or have poor performance. Additionally, proposed protocols are designed only for a single routing primitive–either unicast, multicast, or convergecast. However, as recent WSN applications require diverse traffic patterns, the need for an unified routing framework has ever increased. In this dissertation, we address these main weaknesses in the research on location- based routing. We first propose efficient algorithms for detecting and abstracting CNTs in the network. Using these algorithms, we present our CNT-aware location- based unicast routing protocol that achieves the guaranteed small path stretch with significantly reduced communication overhead. We then present our location-based multicast routing protocol that finds near optimal routing paths from a source node to multicast member nodes, with efficient mechanisms for controllable packet header size and energy-efficient recovery from packet losses. Our CNT-aware convergecast routing protocol improves the network lifetime by identifying network regions with concentrated network traffic and distributing the traffic by using the novel concept of virtual boundaries. Finally, we present the design and implementation details of our unified routing framework that seamlessly integrates proposed unicast, multicast, and convergecast routing protocols. Specifically, we discuss the issues regarding the implementation of our routing protocols on real hardware, and the design of the framework that significantly reduces the code and memory size to fit in a resource constrained sensor mote. We conclude with a proactive solution designed to cope with CNTs, where mobile nodes are used for “patching” CNTs to restore the network connectivity and to optimize the network performance

Efficient and Secure Network Services in Wireless Sensor Networks.

Wireless sensor networks (WSNs) have been deployed for environment monitoring and surveillance. A message delivery service is one of the most fundamental services for WSNs, thus making its efficiency and effectiveness important. A widely-adopted protocol for message delivery in WSNs is a geographic forward routing (GFR), in which messages are greedily forwarded to their destinations. In this thesis, we develop network services complementary to the existing GFR for efficient and secure message delivery in WSNs. We first develop a distributed location service protocol (DLSP) for message delivery to mobile nodes. Since GFR represents destinations of messages with destinations' geographic locations, the knowledge of location of mobile nodes is necessary to ensure correct message delivery. In DLSP, mobile nodes select some sensor nodes as their location servers, and publish the mobiles' location information to the location servers. Sensor nodes contact those location servers to retrieve the current location of mobile nodes when needed. DLSP provides systematic methods for mobile nodes to select location servers and publish their location to those servers, and for sensor nodes to query mobiles' location. We then design an algorithm called Traverse for hole boundary detection and geographic forward routing with hole avoidance (GFRHA) for efficient message routing. Traverse identifies boundaries of holes, i.e., areas without any functioning sensor node. GFRHA then utilizes the identified hole information to route messages around holes while being forwarded before they encounter holes. This way, the message path lengths, and subsequently the message delay and energy consumption, can be significantly reduced, depending on hole shapes and source and destination locations. We also develop attack-resilient collaborative message authentication (ARCMA) for message delivery. ARCMA is designed to tolerate node-capture attacks, in which attackers obtain valid keys by compromising physically-exposed sensor nodes, and use the keys to generate forged messages. To defend against such attacks, in ARCMA, messages are collaboratively authenticated by a set of sensor nodes rather than by one node. The security of ARCMA does not degrade unless attackers simultaneously compromise more than a certain number of sensor nodes.Ph.D.Computer Science & EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/64831/1/mgcho_1.pd

Recent Advances in Multi Robot Systems

To design a team of robots which is able to perform given tasks is a great concern of many members of robotics community. There are many problems left to be solved in order to have the fully functional robot team. Robotics community is trying hard to solve such problems (navigation, task allocation, communication, adaptation, control, ...). This book represents the contributions of the top researchers in this field and will serve as a valuable tool for professionals in this interdisciplinary field. It is focused on the challenging issues of team architectures, vehicle learning and adaptation, heterogeneous group control and cooperation, task selection, dynamic autonomy, mixed initiative, and human and robot team interaction. The book consists of 16 chapters introducing both basic research and advanced developments. Topics covered include kinematics, dynamic analysis, accuracy, optimization design, modelling, simulation and control of multi robot systems

UAV or Drones for Remote Sensing Applications in GPS/GNSS Enabled and GPS/GNSS Denied Environments

The design of novel UAV systems and the use of UAV platforms integrated with robotic sensing and imaging techniques, as well as the development of processing workflows and the capacity of ultra-high temporal and spatial resolution data, have enabled a rapid uptake of UAVs and drones across several industries and application domains.This book provides a forum for high-quality peer-reviewed papers that broaden awareness and understanding of single- and multiple-UAV developments for remote sensing applications, and associated developments in sensor technology, data processing and communications, and UAV system design and sensing capabilities in GPS-enabled and, more broadly, Global Navigation Satellite System (GNSS)-enabled and GPS/GNSS-denied environments.Contributions include:UAV-based photogrammetry, laser scanning, multispectral imaging, hyperspectral imaging, and thermal imaging;UAV sensor applications; spatial ecology; pest detection; reef; forestry; volcanology; precision agriculture wildlife species tracking; search and rescue; target tracking; atmosphere monitoring; chemical, biological, and natural disaster phenomena; fire prevention, flood prevention; volcanic monitoring; pollution monitoring; microclimates; and land use;Wildlife and target detection and recognition from UAV imagery using deep learning and machine learning techniques;UAV-based change detection