Address reuse in wireless sensor networks

Sensor Networks have applications in diverse fields. While unique addressing is not a requirement of many data collecting applications of wireless sensor networks, it is vital for the success of applications such as emergency response. Data that cannot be associated with a specific node becomes useless in such situations. In this work we propose a dynamic addressing mechanism for wireless sensor networks. The scheme enables successful reuse of addresses in event-driven wireless sensor networks. It also eliminates the need for network-wide Duplicate Address Detection (DAD) to ensure uniqueness of network level addresses.<br /

Lease based addressing for event-driven wireless sensor networks

Sensor Networks have applications in diverse fields. They can be deployed for habitat modeling, temperature monitoring and industrial sensing. They also find applications in battlefield awareness and emergency (first) response situations. While unique addressing is not a requirement of many data collecting applications of wireless sensor networks it is vital for the success of applications such as emergency response. Data that cannot be associated with a specific node becomes useless in such situations. In this work we propose an addressing mechanism for event-driven wireless sensor networks. The proposed scheme eliminates the need for network wide Duplicate Address Detection (DAD) and enables reuse of addresses. <br /

PRESTO: A Predictive Storage Architecture for Sensor Networks

We describe PRESTO, a predictive storage architecture for emerging large-scale, hierarchical sensor networks. In contrast to existing techniques, PRESTO is a proxycentric architecture, where tethered proxies balance the need for interactive querying from users with the energy optimization needs of the remote sensors. The main novelty in this work lies in extensive use of predictive techniques that are a natural fit to the correlated behavior of the physical world. PRESTO exploits technology trends in storage to build an architecture that emphasizes archival at remote sensors and intelligent caching at proxies. The system also addresses user needs for querying such sensor networks by exposing a unified, easy to use data abstraction across numerous proxies and remote sensors

Online Enlightenment: A Phidget Notification System for Online Status

This paper describes a physical device that presents online presence information in a semi-public space. The device uses a map metaphor to represent a set of connected labs, showing online instant messenger status for members of the community. Device users can combine information from the device with information from the physical environment to identify unfamiliar lab members, determine human-to-human interaction strategies, and plan meetings. The paper reports on design decisions that were considered in creating the device, supplying rationale for decisions that were made. In particular, we focus on how people integrate physical information from the world and virtual information from this (and similar) devices in the environment, reflecting on ways in which this type of device can improve communication and enhance community. We describe four envisioned usage scenarios for the device, with early feedback from people who work in the space and whose information is displayed on the device

A Critique of Design Approaches for Notification Systems

The Fall 2004 Virginia Tech Undergraduate Research in Computer Science (VTURCS) class, taught by Dr. McCrickard, covered the following topics: problem, activity and information/interaction phases of design; scenario based design; interruption, reaction, and comprehension (IRC) values; stages of action; ubiquitous computing evaluation areas (UEAs) and participatory negotiation. This critique is my assessment and observations of how these design approaches worked for our project

An Ontology-Based Context Model for Managing Security Knowledge in Software Development

Software security has been the focus of the security community and practitioners over the past decades. Much security information is widely available in books, open literature or on the internet. We argue that the generated huge mass of information has resulted in a form of information overload to software engineers who usually finish reading it without being able to apply those principles clearly to their own application context. Our research tackles software security issues from a knowledge management perspective. In this paper, we present an ontology approach to model the knowledge of software security in a context- sensitive manner, supporting software engineers and learners to enable the correlation process between security domain knowledge and their working context. We also propose a web-based application for security knowledge sharing and learning where the ontology is adopted as the central knowledge repository

Improved Bluetooth Key Exchange using Unbalanced RSA

In this thesis, a new protocol is proposed for the Bluetooth Key Exchange. The proposed key exchange will make use of a public-key algorithm as compared to the currently existing key exchange which only uses symmetric ciphers. The public-key algorithm to be used is a modified version of the RSA algorithm called Unbalanced RSA . The proposed scheme will improve on the currently existing key exchange scheme by improving the security while trying to minimize computation time. The proposed protocol will also improve on a recent work which used the Diffie-Hellman algorithm for Bluetooth key exchange. In using the Diffie-Hellman algorithm the security was increased from the original Bluetooth key exchange but the computation time and difficulty of computations was also increased. Two Bluetooth devices that are trying to communicate can have a wide range of processor speeds and the use of the Diffie-Hellman protocol can cause a large delay at one user. The use of Unbalanced RSA in the proposed protocol will aim to remedy this problem. The aim of the proposed protocol is to eliminate the security risks from the original Bluetooth key exchange and also address the computation time issue with the enhanced Diffie-Hellman key exchange

Energy scavenging for long-term deployable wireless sensor networks

The coming decade will see the rapid emergence of low cost, intelligent, wireless sensors and their widespread deployment throughout our environment. While wearable systems will operate over communications ranges of less than a meter, building management systems will operate with inter-node communications ranges of the order of meters to tens of meters and remote environmental monitoring systems will require communications systems and associated energy systems that will allow reliable operation over kilometers. Autonomous power should allow wireless sensor nodes to operate in a “deploy and forget” mode. The use of rechargeable battery technology is problematic due to battery lifetime issues related to node power budget, battery self-discharge, number of recharge cycles and long-term environmental impact. Duty cycling of wireless sensor nodes with long “SLEEP” times minimises energy usage. A case study of a multi-sensor, wireless, building management system operating using the Zigbee protocol demonstrates that, even with a 1 min cycle time for an 864 ms “ACTIVE” mode, the sensor module is already in SLEEP mode for almost 99% of the time. For a 20-min cycle time, the energy utilisation in SLEEP mode exceeds the ACTIVE mode energy by almost a factor of three and thus dominates the module energy utilisation thereby providing the ultimate limit to the power system lifetime. Energy harvesting techniques can deliver energy densities of 7.5 mW/cm2 from outdoor solar, 100 μW/cm2 from indoor lighting, 100 μW/cm3 from vibrational energy and 60 μW/cm2 from thermal energy typically found in a building environment. A truly autonomous, “deploy and forget” battery-less system can be achieved by scaling the energy harvesting system to provide all the system energy needs. In the building management case study discussed, for duty cycles of less than 0.07% (i.e. in ACTIVE mode for 0.864 s every 20 min), energy harvester device dimensions of approximately 2 cm on a side would be sufficient to supply the complete wireless sensor node energy. Key research challenges to be addressed to deliver future, remote, wireless, chemo-biosensing systems include the development of low cost, low-power sensors, miniaturised fluidic transport systems, anti-bio-fouling sensor surfaces, sensor calibration, reliable and robust system packaging, as well as associated energy delivery systems and energy budget management

Optimal Control with Information Pattern Constraints

Despite the abundance of available literature that starts with the seminal paper of Wang and Davison almost forty years ago, when dealing with the problem of decentralized control for linear dynamical systems, one faces a surprising lack of general design methods, implementable via computationally tractable algorithms. This is mainly due to the fact that for decentralized control configurations, the classical control theoretical framework falls short in providing a systematic analysis of the stabilization problem, let alone cope with additional optimality criteria. Recently, a significant leap occurred through the theoretical machinery developed in Rotkowitz and Lall, IEEE-TAC, vol. 51, 2006, pp. 274-286 which unifies and consolidates many previous results, pinpoints certain tractable decentralized control structures, and outlines the most general known class of convex problems in decentralized control. The decentralized setting is modeled via the structured sparsity constraints paradigm, which proves to be a simple and effective way to formalize many decentralized configurations where the controller feature a given sparsity pattern. Rotkowitz and Lall propose a computationally tractable algorithm for the design of H2 optimal, decentralized controllers for linear and time invariant systems, provided that the plant is strongly stabilizable. The method is built on the assumption that the sparsity constraints imposed on the controller satisfy a certain condition (named quadratic invariance) with respect to the plant and that some decentralized, strongly stablizable, stabilizing controller is available beforehand. For this class of decentralized feedback configurations modeled via sparsity constraints, so called quadratically invariant, we provided complete solutions to several open problems. Firstly, the strong stabilizability assumption was removed via the so called coordinate free parametrization of all, sparsity constrained controllers. Next we have addressed the unsolved problem of stabilizability/stabilization via sparse controllers, using a particular form of the celebrated Youla parametrization. Finally, a new result related to the optimal disturbance attenuation problem in the presence of stable plant perturbations is presented. This result is also valid for quadratically invariant, decentralized feedback configurations. Each result provides a computational, numerically tractable algorithm which is meaningful in the synthesis of sparsity constrained optimal controllers

Low power wireless sensor applications.

Yuen Chi Lap.Thesis (M.Phil.)--Chinese University of Hong Kong, 2004.Includes bibliographical references (leaves 88-94).Abstracts in English and Chinese.Chapter 1 --- Introduction --- p.1Chapter 1.1 --- Motivation --- p.1Chapter 1.2 --- Aims --- p.2Chapter 1.3 --- Contributions --- p.3Chapter 1.4 --- Thesis Organization --- p.4Chapter 2 --- Background and Literature Review --- p.5Chapter 2.1 --- Introduction --- p.5Chapter 2.2 --- Vibration-to-Electrical Transducer --- p.6Chapter 2.2.1 --- Electromagnetic (Inductive) Power Conversion --- p.6Chapter 2.2.2 --- Electrostatic(Capacitive) Power Conversion --- p.8Chapter 2.2.3 --- Piezoelectric Power Conversion --- p.9Chapter 2.3 --- Wireless Sensor Platform Examples --- p.11Chapter 2.3.1 --- MICA[13] from UC Berkeley[49] --- p.11Chapter 2.3.2 --- WINS[48] from UCLA[51] --- p.13Chapter 2.3.3 --- Wong's Infrared System[5] --- p.13Chapter 2.4 --- Summary --- p.14Chapter 3 --- Micro Power Generator --- p.16Chapter 3.1 --- Introduction --- p.16Chapter 3.2 --- MEMS Resonator --- p.18Chapter 3.2.1 --- Laser-machinery --- p.18Chapter 3.2.2 --- Electroplating Fabrication --- p.18Chapter 3.3 --- Voltage Multiplier --- p.19Chapter 3.4 --- "Modeling, Simulations and Measurements" --- p.21Chapter 3.5 --- Summary --- p.30Chapter 4 --- Low Power Wireless Sensor Platform --- p.37Chapter 4.1 --- Introduction --- p.37Chapter 4.2 --- Generic Platform --- p.37Chapter 4.2.1 --- Startup Module and Power Management --- p.38Chapter 4.2.2 --- Control Unit --- p.43Chapter 4.2.3 --- Input Units (Sensor Peripherals) --- p.46Chapter 4.2.4 --- Output Units (Wireless Transmitters) --- p.48Chapter 4.3 --- Summary --- p.57Chapter 5 --- Application I - Wireless RF Thermometer --- p.59Chapter 5.1 --- Overview --- p.59Chapter 5.2 --- Implementation --- p.60Chapter 5.2.1 --- Prototype 1 --- p.60Chapter 5.2.2 --- Prototype 2 --- p.60Chapter 5.2.3 --- Prototype 3 --- p.62Chapter 5.2.4 --- Prototype 4 --- p.63Chapter 5.3 --- Results --- p.65Chapter 5.4 --- Summary --- p.67Chapter 6 --- Application II - 2D Input Ring --- p.70Chapter 6.1 --- Overview --- p.70Chapter 6.2 --- Architecture --- p.70Chapter 6.3 --- Software Implementation --- p.72Chapter 6.3.1 --- Methodology --- p.72Chapter 6.3.2 --- Error Control Code --- p.73Chapter 6.3.3 --- Peripheral Control Protocol --- p.75Chapter 6.4 --- Results --- p.77Chapter 6.5 --- Summary --- p.83Chapter 7 --- Conclusion --- p.84Chapter 7.1 --- Micro power generator --- p.84Chapter 7.2 --- Low power wireless sensor applications --- p.85Chapter 7.2.1 --- Wireless thermometer --- p.85Chapter 7.2.2 --- 2D input ring --- p.86Chapter 7.3 --- Further development --- p.86Bibliography --- p.88Chapter A --- Schematics --- p.9