1 Sensor Networks and Networked Societies of Artifacts Jose Rolim University of Geneva

PERAD 2007Jose Rolim2 Why sensor networks?  Invisible, everywhere computing  Invisible computing: Tiny Embedded Attached …  Everywhere computing: Wireless Dynamic Configurable Remote Access Adapting …  Sensor Networks seems to be the typical example

PERAD 2007Jose Rolim3 Definition  “Sensor networks are collections of wirelessly interconnected devices with sensing, computing and communication infrastructure that allow us to instrument, observe, and respond to phenomena in the natural environment and physical infrastructure.”

PERAD 2007Jose Rolim4 Some Goals of Pervasive Computing  Invisible technology  Integration of virtual and physical worlds throughout desks, rooms, building, life, society  Take the data out of the information, leaving just an enhanced ability to act

PERAD 2007Jose Rolim5 Situated Networking  Makes use of simple shared context:  Space  Time  Proximity  Participation in the context:  Physical  Out here with us  Many small and large places

PERAD 2007Jose Rolim6 Difficulties of Pervasive Networking  Network explosion  Impossibility of a centralized management  Network heterogeneity (not only sensors but also laptops, servers, etc..)  The use of adapted standard theoretical models, algorithms and protocols is impossible

PERAD 2007Jose Rolim7 Why the Standard Approaches Fail  At the modeling level (ex: limited energy)  At the networking level (ex: scalability)  At the management level (ex: radically distributed)  At the service level (ex: situated nature)

PERAD 2007Jose Rolim8 Our aim:  A communication system supporting millions of localized services in an networked society consisting of billions of heterogeneous nodes, intermittently connected and invisible

PERAD 2007Jose Rolim9 Issues for sensor networking -1  Technology independent models of sensor networking  Dynamic models of sensor distributed computing  Self-organization in sensor networks  Distributed cost sharing mechanisms  Energy management, balancing and complexity formulation  Models of collaboration and competition for resources

PERAD 2007Jose Rolim10 Issues for sensor networking -2  Nature inspired control and adaptation mechanisms  Global impact of the local sensor interactions  Models of ad-hoc deployment  Efficient approach to mobility

PERAD 2007Jose Rolim11 Issues for sensor networking -3  Energy aware algorithms and protocols for:  Self configuration, reconfiguration and localization of sensors  Long vs short range algorithms  Resilience and robustness mechanisms  Pervasive communication for routing, interference and congestion control  Achievement of global tasks via local, event driven interactions

PERAD 2007Jose Rolim12 How to tackle these issues?  Techniques from TCS  Techniques from Game Theory  Techniques from Natural Computing  Techniques from Networking Information Theory  Techniques from Distributed Computing  Most importantly: integration among those techniques

PERAD 2007Jose Rolim13 Techniques from TCS  Examples:  Extended Random Graphs Models  Geometric Approaches  Probabilistic Algorithms  Markov Chains

PERAD 2007Jose Rolim14 Techniques from Game Theory  Examples:  Nash Equilibrium  Game Theoretic Methods for Enforcing Cooperation  Security Issues  Evolutionary Game Theory  Reputation Systems

PERAD 2007Jose Rolim15 Techniques from Natural Computing  Examples:  Adaptation by evolution  Learning from experience  Evolutionary genetics  Biological networks  Complex ecosystems  Swarm intelligence

PERAD 2007Jose Rolim16 Techniques from Distributed Computing  Examples:  Approximate counting  Randomized methods with noisy information  Manets mechanisms- mobility  Obstacle avoidance  Power saving schemes

PERAD 2007Jose Rolim17 Example

PERAD 2007Jose Rolim18 Example 2

PERAD 2007Jose Rolim19 Ex

PERAD 2007Jose Rolim20

PERAD 2007Jose Rolim21

PERAD 2007Jose Rolim22

PERAD 2007Jose Rolim23  Energy cost:  Square of distance

PERAD 2007Jose Rolim24

PERAD 2007Jose Rolim25

PERAD 2007Jose Rolim26 The Problem

PERAD 2007Jose Rolim27 A distributed algorithm

PERAD 2007Jose Rolim28 Illustration

PERAD 2007Jose Rolim29 Stability  Markov Chain

PERAD 2007Jose Rolim30 Mix of techniques  Theory  Game  Natural computing  Network information  Distributed computing  Mix