Wireless sensor network (WSN) is an ad-hoc network technology comprising even thousands of autonomic and self-organizing nodes that combine environmental sensing, data processing, and wireless networking. The applications for sensor networks range from home and industrial environments to military uses. Unlike the traditional computer networks, a WSN is application-oriented and deployed for a specific task. WSNs are data centric, which means that messages are not send to individual nodes but to geographical locations or regions based on the data content. A WSN node is typically battery powered and characterized by extremely small size and low cost.

As a result, the processing power, memory, and energy resources of an individual sensor node are limited. However, the feasibility of a WSN lies on the collaboration between the nodes. A reference WSN node comprises a Micro-Controller Unit (MCU) having few Million Instructions Per Second (MIPS) processing speed, tens of kilobytes program memory, few kilobytes data memory. In addition, the node contains a short-range radio, and a set of sensors. Supply power is typically obtained with small batteries. Assuming a target lifetime of one year using AA-size batteries, the available power budget is around 1 mW.

This book covers the low-power WSNs services ranging from hardware platforms and communication protocols to network deployment, and sensor data collection and actuation. The implications of resource constraints and expected performance in terms of throughput, reliability and latency are explained. As a case study, this book presents experiments with low-energy TUTWSN technology to illustrate the possibilities and limitations of WSN applications.

This book constitutes the refereed proceedings of the 7th International Workshop on Systems, Architectures, Modeling, and Simulation, SAMOS 2007, held in Samos, Greece in July 2007.

The 44 revised full papers presented together with 2 keynote talks were thoroughly reviewed and selected from 116 submissions. The papers are organized in topical sections on system modeling and simulation, VLSI architectures, scheduling and programming models, multi-processor architectures, reconfigurable architectures, design space exploration, processor components, embedded processors, SoC for SDR, and wireless sensors.

The SAMOS workshop is an international gathering of highly quali?ed researchers from academia and industry, sharing in a 3-day lively discussion on the quiet and - spiring northern mountainside of the Mediterranean island of Samos. As a tradition, the workshop features workshop presentations in the morning, while after lunch all kinds of informal discussions and nut-cracking gatherings take place. The workshop is unique in the sense that not only solved research problems are presented and discussed but also (partly) unsolved problems and in-depth topical reviews can be unleashed in the sci- ti?c arena. Consequently, the workshop provides the participants with an environment where collaboration rather than competition is fostered. The earlier workshops, SAMOS I-IV (2001-2004), were composed only of invited presentations. Due to increasing expressions of interest in the workshop, the Program Committee of SAMOS V decided to open the workshop for all submissions. As a result the SAMOS workshop gained an immediate popularity; a total of 114 submitted papers were received for evaluation. The papers came from 24 countries and regions: Austria (1), Belgium (2), Brazil (5), Canada (4), China (12), Cyprus (2), Czech Republic (1), Finland (15), France (6), Germany (8), Greece (5), Hong Kong (2), India (2), Iran (1), Korea (24), The Netherlands (7), Pakistan (1), Poland (2), Spain (2), Sweden (2), T- wan (1), Turkey (2), UK (2), and USA (5). We are grateful to all of the authors who submitted papers to the workshop.

This book constitutes the refereed proceedings of the 6th International Workshop on Systems, Architectures, Modeling, and Simulation, SAMOS 2006, held in Samos, Greece on July 2006.

The 47 revised full papers presented together with 2 keynote talks were thoroughly reviewed and selected from 130 submissions. The papers are organized in topical sections on system design and modeling, wireless sensor networks, processor design, dependable computing, architectures and implementations, as well as embedded sensor systems.