DCOS, a Real-Time Light-weight Data Centric Operating System

DCOS is a Data Centric lightweight Operating System for embedded devices. Despite limited energy and hardware resources, it supports a data driven architecture with provisions for dynamic loadable Modules. It combines these with Real-Time provisions based on Earliest Deadline First with a simple but smart resource handling mechanism. We will give an overview of the capabilities of DCOS and we will describe the basics of the main mechanisms

On the design of an energy-efficient low-latency integrated protocol for distributed mobile sensor networks

Self organizing, wireless sensors networks are an emergent and challenging technology that is attracting large attention in the sensing and monitoring community. Impressive progress has been done in recent years even if we need to assume that an optimal protocol for every kind of sensor network applications can not exist. As a result it is necessary to optimize the protocol for certain scenarios. In many applications for instance latency is a crucial factor in addition to energy consumption. MERLIN performs its best in such WSNs where there is the need to reduce the latency while ensuring that energy consumption is kept to a minimum. By means of that, the low latency characteristic of MERLIN can be used as a trade off to extend node lifetimes. The performance in terms of energy consumption and latency is optimized by acting on the slot length. MERLIN is designed specifically to integrate routing, MAC and localization protocols together. Furthermore it can support data queries which is a typical application for WSNs. The MERLIN protocol eliminates the necessity to have any explicit handshake mechanism among nodes. Furthermore, the reliability is improved using multiple path message propagation in combination with an overhearing mechanism. The protocol divides the network into subsets where nodes are grouped in time zones. As a result MERLIN also shows a good scalability by utilizing an appropriate scheduling mechanism in combination with a contention period

Architectures for wireless sensor networks

The vision of ubiquitous computing requires the development of devices and technologies that can be pervasive without being intrusive. The basic component of such a smart environment will be a small node with sensing and wireless communications capabilities, able to organize itself flexibly into a network for data collection and delivery. Building such a sensor network presents many significant challenges, especially at the architectural, protocol, and operating system level. Although sensor nodes might be equipped with a power supply or energy scavenging means and an embedded processor that makes them autonomous and self-aware, their functionality and capabilities will be very limited. Therefore, collaboration between nodes is essential to deliver smart services in a ubiquitous setting. New algorithms for networking and distributed collaboration need to be developed. These algorithms will be the key for building self-organizing and collaborative sensor networks that show emergent behavior and can operate in a challenging environment where nodes move, fail, and energy is a scarce resource. The question that rises is how to organize the internal software and hardware components in a manner thatwill allowthem towork properly and be able to adapt dynamically to new environments, requirements, and applications. At the same time the solution should be general enough to be suited for as many applications as possible. Architecture definition also includes, at the higher level, a global view of the whole network. The topology, placement of base stations, beacons, etc. is also of interest. In this chapter, we will present and analyze some of the characteristics of the architectures for wireless sensor networks. Then, we will propose a new dataflow-based architecture that allows, as a new feature, the dynamic reconfiguration of the sensor nodes software at runtime

Nearest Neighbor Connectivity in Two-Dimensional Multihop MANETs

A Mobile Ad Hoc Network (MANET) is characterized to be a network with free, cooperative, and dynamic nodes, self-organized in a random topology, without any kind of infrastructure, where the communication between two nodes usually occurs using multihop paths. The number of hops used in the multihop path is an important metric for the design and performance analysis of routing protocols in MANETs. In this paper, we derive the probability distribution of the hop count of a multihop path between a source node and a destination node, fixed at a known distance from each other, and when a fixed number of nodes are uniformly distributed in a region of interest. This distribution is obtained by the Poisson randomization method. To obtain the multihop path, we propose a novel routing model in which the nearest distance routing protocol (NR) is analyzed. Numerical results are obtained to evaluate the performance of the NR

Introduction to wireles sensor networks

Wireless Sensor Networks have gained a lot of attention lately. Due to technological advances, building small-sized, energy-efficient reliable devices, capable of communicating with each other and organizing themselves in ad hoc networks have become possible. These devices have brought a new perspective to the world of computers as we know it: they can be embedded into the environment in such a way that the user is unaware of them. There is no need for reconfiguration and maintenance as the network organizes itself to inform the users of the most relevant events detected or to assist them in their activity. This chapter will give a brief overview of the whole area, by introducing the wireless sensor networks concepts to the reader. Then, a number of applications aswell as possible typical scenarioswill be presented in order to better understand the field of application of this new emerging technology. Up to this moment, several main areas of applications have been identified. New areas of applications are still to be discovered as the research and products grow more mature. Wireless sensor networks bring lots of challenges and often contradictory demands from the design point of view. The last part of the chapter will be dedicated to highlighting the main directions of research involved in this field. It will serve as a brief introduction to the problems to be described in the following chapters of the book

Assessing Security-Critical Energy-Efficient Sensor Networks

In the EYES project, we are investigating self-organizing, collaborative, energy-efficient sensor networks. This study is devoted to the security aspects of the project. Our contribution is three-fold: firstly, we present a survey, where we discuss the dominant issues of energy-security trade-off in the network protocol and key management design space. From there we set out future research directions for our security framework. Secondly, we propose an assessment framework based on system profile, with which we have managed to carve out manageable design spaces from the seemingly infinite possibilities of ad hoc mobile wireless networks. Finally, we have benchmarked some well-known cryptographic algorithms in search for the best compromise in security and energy-efficiency, on a typical sensor node. Our preliminary investigations also cover an important parameter in the design space: the resource requirements of the symmetric key algorithms RC5 and TE