Thomas F. La Porta

Movement-assisted sensor deployment

Abstract-Adequate coverage is very important for sensor networks to fulfill the issued sensing tasks. In many working environments, it is necessary to make use of mobile sensors, which can move to the correct places to provide the required coverage. In this paper, we study the problem of placing mobile sensors to get high coverage. Based on Voronoi diagrams, we design two sets of distributed protocols for controlling the movement of sensors, one favoring communication and one favoring movement. In each set of protocols, we use Voronoi diagrams to detect coverage holes and use one of three algorithms to calculate the target locations of sensors it holes exist. Simulation results show the effectiveness of our protocols and give insight on choosing protocols and calculation algorithms under different application requirements and working conditions.

Demo: Medusa: a programming framework for crowd-sensing applications

The ubiquity of smartphones and their on-board sensing capabilities motivates crowd-sensing, a capability that harnesses the power of crowds to collect sensor data from a large number of mobile phone users. Unlike previous work on wireless sensing, crowd-sensing poses several novel requirements: support for humans-in-the-loop to trigger sensing actions or review results, the need for incentives, as well as privacy and security. Beyond existing crowd-sourcing systems, crowd-sensing exploits sensing and processing capabilities of mobile devices. In this paper, we design and implement Medusa, a novel programming framework for crowd-sensing that satisfies these requirements. Medusa provides high-level abstractions for specifying the steps required to complete a crowd-sensing task, and employs a distributed runtime system that coordinates the execution of these tasks between smartphones and a cluster on the cloud. We have implemented ten crowd-sensing tasks on a prototype of Medusa. We find that Medusa task descriptions are two orders of magnitude smaller than standalone systems required to implement those crowd-sensing tasks, and the runtime has low overhead and is robust to dynamics and resource attacks.

On cellular botnets: measuring the impact of malicious devices on a cellular network core

The vast expansion of interconnectivity with the Internet and the rapid evolution of highly-capable but largely insecure mobile devices threatens cellular networks. In this paper, we characterize the impact of the large scale compromise and coordination of mobile phones in attacks against the core of these networks. Through a combination of measurement, simulation and analysis, we demonstrate the ability of a botnet composed of as few as 11,750 compromised mobile phones to degrade service to area-code sized regions by 93%. As such attacks are accomplished through the execution of network service requests and not a constant stream of phone calls, users are unlikely to be aware of their occurrence. We then investigate a number of significant network bottlenecks, their impact on the density of compromised nodes per base station and how they can be avoided. We conclude by discussing a number of countermeasures that may help to partially mitigate the threats posed by such attacks.

SET: Detecting node clones in sensor networks

Sensor nodes that are deployed in hostile environments are vulnerable to capture and compromise. An adversary may obtain private information from these sensors, clone and intelligently deploy them in the network to launch a variety of insider attacks. This attack process is broadly termed as a clone attack. Currently, the defenses against clone attacks are not only very few, but also suffer from selective interruption of detection and high overhead (computation and memory). In this paper, we propose a new effective and efficient scheme, called SET, to detect such clone attacks. The key idea of SET is to detect clones by computing set operations (intersection and union) of exclusive subsets in the network. First, SET securely forms exclusive unit subsets among one-hop neighbors in the network in a distributed way. This secure subset formation also provides the authentication of nodes’ subset membership. SET then employs a tree structure to compute non-overlapped set operations and integrates interleaved authentication to prevent unauthorized falsification of subset information during forwarding. Randomization is used to further make the exclusive subset and tree formation unpredictable to an adversary. We show the reliability and resilience of SET by analyzing the probability that an adversary may effectively obstruct the set operations. Performance analysis and simulations also demonstrate that the proposed scheme is more efficient than existing schemes from both communication and memory cost standpoints.

Sensor Network Operations

PREFACE. CONTRIBUTORS. I SENSOR NETWORK OPERATIONS OVERVIEW. 1 Overview of Mission-Oriented Sensor Networks. 1.1 Introduction. 1.2 Trends in Sensor Development. 1.3 Mission-Oriented Sensor Networks: Dynamic Systems Perspective. References. II SENSOR NETWORK DESIGN AND OPERATIONS. 2 Sensor Deployment, Self-Organization, and Localization. 2.1 Introduction. 2.2 SCARE: A Scalable Self-Configuration and Adaptive Reconfiguration Scheme for Dense Sensor Networks. 2.3 Robust Sensor Positioning in Wireless Ad Hoc Sensor Networks. 2.4 Trigonometric k Clustering (TKC) for Censored Distance Estimation. 2.5 Sensing Coverage and Breach Paths in Surveillance Wireless Sensor Networks. References. 3 Purposeful Mobility and Navigation. 3.1 Introduction. 3.2 Controlled Mobility for Efficient Data Gathering in Sensor Networks with Passively Mobile Nodes. 3.3 Purposeful Mobility in Tactical Sensor Networks. 3.4 Formation and Alignment of Distributed Sensing Agents with Double-Integrator Dynamics and Actuator Saturation. 3.5 Modeling and Enhancing the Data Capacity of Wireless Sensor Networks. References. 4 Lower Layer Issues-MAC, Scheduling, and Transmission. 4.1 Introduction. 4.2 SS-TDMA: A Self-Stabilizing Medium Access Control (MAC) for Sensor Networks. 4.3 Comprehensive Performance Study of IEEE 802.15.4. 4.4 Providing Energy Efficiency for Wireless Sensor Networks Through Link Adaptation Techniques. References. 5 Network Routing. 5.1 Introduction. 5.2 Load-Balanced Query Protocols for Wireless Sensor Networks. 5.3 Energy-Efficient and MAC-Aware Routing for Data Aggregation in Sensor Networks. 5.4 LESS: Low-Energy Security Solution for Large-scale Sensor Networks Based on Tree-Ripple-Zone Routing Scheme. References. 6 Power Management. 6.1 Introduction. 6.2 Adaptive Sensing and Reporting in Energy-Constrained Sensor Networks. 6.3 Sensor Placement and Lifetime of Wireless Sensor Networks: Theory and Performance Analysis. 6.4 Algorithms for Maximizing Lifetime of Battery-Powered Wireless Sensor Nodes. 6.5 Battery Lifetime Estimation and Optimization for Underwater Sensor Networks. References. 7 Distributed Sensing and Data Gathering. 7.1 Introduction. 7.2 Secure Differential Data Aggregation for Wireless Sensor Networks. 7.3 Energy-Conserving Data Gathering Strategy Based on Trade-off Between Coverage and Data Reporting Latency in Wireless Sensor Networks. 7.4 Quality-Driven Information Processing and Aggregation in Distributed Sensor Networks. 7.5 Progressive Approach to Distributed Multiple-Target Detection in Sensor Networks. References. 8 Network Security. 8.1 Introduction. 8.2 Energy Cost of Embedded Security for Wireless Sensor Networks. 8.3 Increasing Authentication and Communication Confidentiality in Wireless Sensor Networks. 8.4 Efficient Pairwise Authentication Protocols for Sensor and Ad Hoc Networks. 8.5 Fast and Scalable Key Establishment in Sensor Networks. 8.6 Weil Pairing-Based Round, Efficient, and Fault-Tolerant Group Key Agreement Protocol for Sensor Networks. References. III SENSOR NETWORK APPLICATIONS. 9 Pursuer-Evader Tracking in Sensor Networks. 9.1 Introduction. 9.2 The Problem. 9.3 Evader-Centric Program. 9.4 Pursuer-Centric Program. 9.5 Hybrid Pursuer-Evader Program. 9.6 Efficient Version of Hybrid Program. 9.7 Implementation and Simulation Results. 9.8 Discussion and Related Work. References. 10 Embedded Soft Sensing for Anomaly Detection in Mobile Robotic Networks. 10.1 Introduction. 10.2 Mobile Robot Simulation Setup. 10.3 Software Anomalies in Mobile Robotic Networks. 10.4 Soft Sensor. 10.5 Software Anomaly Detection Architecture. 10.6 Anomaly Detection Mechanisms. 10.7 Test Bed for Software Anomaly Detection in Mobile Robot Application. 10.8 Results and Discussion. 10.9 Conclusions and Future Work. Appendix A. Appendix B. References. 11 Multisensor Network-Based Framework for Video Surveillance: Real-Time Superresolution Imaging. 11.1 Introduction. 11.2 Basic Model of Distributed Multisensor Surveillance System. 11.3 Superresolution Imaging. 11.4 Optical Flow Computation. 11.5 Superresolution Image Reconstruction. 11.6 Experimental Results. 11.7 Conclusion. References. 12 Using Information Theory to Design Context-Sensing Wearable Systems. 12.1 Introduction. 12.2 Related Work. 12.3 Theoretical Background. 12.4 Adaptations. 12.5 Design Considerations. 12.6 Case Study. 12.7 Results. 12.8 Conclusion. Appendix. References. 13 Multiple Bit Stream Image Transmission over Wireless Sensor Networks. 13.1 Introduction. 13.2 System Description. 13.3 Experimental Results. 13.4 Summary and Discussion. References. 14 Hybrid Sensor Network Test Bed for Reinforced Target Tracking. 14.1 Introduction. 14.2 Sensor Network Operational Components. 14.3 Sensor Network Challenge Problem. 14.4 Integrated Target Surveillance Experiment. 14.5 Experimental Results and Evaluation. 14.6 Conclusion. References. 15 Noise-Adaptive Sensor Network for Vehicle Tracking in the Desert. 15.1 Introduction. 15.2 Distributed Tracking. 15.3 Algorithms. 15.4 Experimental Methods. 15.5 Results and Discussion. 15.6 Conclusion. References. ACKNOWLEDGMENTS. INDEX. ABOUT THE EDITORS.

Mitigating attacks on open functionality in SMS-capable cellular networks

The transformation of telecommunications networks from homogeneous closed systems providing only voice services to Internet-connected open networks that provide voice and data services presents significant security challenges. For example, recent research illustrated that a carefully crafted DoS attack via text messaging could incapacitate all voice communications in a metropolitan area with little more than a cable modem. This attack highlights a growing threat to these systems; namely, cellular networks are increasingly exposed to adversaries both in and outside the network. In this paper, we use a combination of modeling and simulation to demonstrate the feasibility of targeted text messaging attacks. Under realistic network conditions, we show that adversaries can achieve blocking rates of more than 70% with only limited resources. We then develop and characterize five techniques from within two broad classes of countermeasures-queue management and resource provisioning. Our analysis demonstrates that these techniques can eliminate or extensively mitigate even the most intense targeted text messaging attacks. We conclude by considering the tradeoffs inherent to the application of these techniques in current and next generation telecommunications networks.

Challenges for nomadic computing: mobility management and wireless communications

In this paper, we present several challenges and innovative approaches to support nomadic computing. The nomadic computing environment is characterized by mobile users that may be connected to the network via wired or wireless means, many of whom will maintain only intermittent connectivity with the network. Furthermore, those accessing the network via wireless links will contend with limitations of the wireless media. We consider three general techniques for addressing these challenges: (1) asymmetric design of applications and protocols, (2) the use of network-based proxies which perform complex functions on behalf of mobile users, and (3) the use of pre-fetching and caching of critical data. We examine how these techniques have been applied to several systems, and present results in an attempt to quantify their relative effectiveness.

Intra-cloud lightning: Building CDNs in the cloud

Content distribution networks (CDNs) using storage clouds have recently started to emerge. Compared to traditional CDNs, storage cloud-based CDNs have the advantage of cost effectively offering hosting services to Web content providers without owning infrastructure. However, existing work on replica placement in CDNs does not readily apply in the cloud. In this paper, we investigated the joint problem of building distribution paths and placing Web server replicas in cloud CDNs to minimize the cost incurred on the CDN providers while satisfying QoS requirements for user requests. We formulate the cost optimization problem with accurate cost models and QoS requirements and show that the monthly cost can be as low as 2.62 US Dollars for a small Web site. We develop a suite of offline, online-static and online-dynamic heuristic algorithms that take as input network topology and work load information such as user location and request rates. We then evaluate the heuristics via Web trace-based simulation, and show that our heuristics behave very close to optimal under various network conditions.

Efficient and Privacy-Aware Data Aggregation in Mobile Sensing

The proliferation and ever-increasing capabilities of mobile devices such as smart phones give rise to a variety of mobile sensing applications. This paper studies how an untrusted aggregator in mobile sensing can periodically obtain desired statistics over the data contributed by multiple mobile users, without compromising the privacy of each user. Although there are some existing works in this area, they either require bidirectional communications between the aggregator and mobile users in every aggregation period, or have high-computation overhead and cannot support large plaintext spaces. Also, they do not consider the Min aggregate, which is quite useful in mobile sensing. To address these problems, we propose an efficient protocol to obtain the Sum aggregate, which employs an additive homomorphic encryption and a novel key management technique to support large plaintext space. We also extend the sum aggregation protocol to obtain the Min aggregate of time-series data. To deal with dynamic joins and leaves of mobile users, we propose a scheme that utilizes the redundancy in security to reduce the communication cost for each join and leave. Evaluations show that our protocols are orders of magnitude faster than existing solutions, and it has much lower communication overhead.

Social-Based Cooperative Caching in DTNs: A Contact Duration Aware Approach

Data access is an important issue in Delay Tolerant Networks (DTNs), and a common technique to improve the performance of data access is cooperative caching. However, due to the unpredictable node mobility in DTNs, traditional caching schemes cannot be directly applied. In this paper, we propose DAC, a novel caching protocol adaptive to the challenging environment of DTNs. Specifically, we exploit the social community structure to combat the unstable network topology in DTNs. We propose a new centrality metric to evaluate the caching capability of each node within a community, and solutions based on this metric are proposed to determine where to cache. More importantly, we consider the impact of the contact duration limitation on cooperative caching, which has been ignored by the existing works. We prove that the marginal caching benefit that a node can provide diminishes when more data is cached. We derive an adaptive caching bound for each mobile node according to its specific contact patterns with others, to limit the amount of data it caches. In this way, both the storage space and the contact opportunities are better utilized. To mitigate the coupon collectors problem, network coding techniques are used to further improve the caching efficiency. Extensive trace-driven simulations show that our cooperative caching protocol can significantly improve the performance of data access in DTNs.