Automatic application object migration in sensor networks

Object migration in wireless sensor networks has the potential to reduce energy consumption for a wireless sensor network mesh. Automated migration reduces the need for the programmer to perform manual static analysis to find an efficient layout solution. Instead, the system can self-optimise and adjust to changing conditions. This paper describes an automated, transparent object migration system for wireless sensor networks, implemented on a micro Java virtual machine. The migration system moves objects at runtime around the sensor mesh to reduce communication overheads. The movement of objects is transparent to the application developer. Automated transparent object migration is a core component of Hydra, a distributed operating system for wireless sensor networks that is currently under development. Performance of the system under a complex performance test scenario using a real-world dataset of seismic events is described. The results show that under both simple and complex conditions the migration technique can result in lower data traffic and consequently lower overall energy cost

Distributed OpenGL Rendering in Network Bandwidth Constrained Environments

Display walls made from multiple monitors are often used when very high resolution images are required. To utilise a display wall, rendering information must be sent to each computer that the monitors are connect to. The network is often the performance bottleneck for demanding applications, like high performance 3D animations. This paper introduces ClusterGL; a distribution library for OpenGL applications. ClusterGL reduces network traffic by using compression, frame differencing and multi-cast. Existing applications can use ClusterGL without recompilation. Benchmarks show that, for most applications, ClusterGL outperforms other systems that support unmodified OpenGL applications including Chromium and BroadcastGL. The difference is larger for more complex scene geometries and when there are more display machines. For example, when rendering OpenArena, ClusterGL outperforms Chromium by over 300% on the Symphony display wall at The University of Waikato, New Zealand. This display has 20 monitors supported by five computers connected by gigabit Ethernet, with a full resolution of over 35 megapixels. ClusterGL is freely available via Google Code

Distributed Operating Systems on Wireless Sensor Networks

This thesis proposes the use of traditional distributed operating system and distributed systems techniques that are adapted and applied to the wireless sensor network domain. These techniques are applied to the creation of a wireless sensor network operating system that allows complex applications to be created without special programmer knowledge of sensor network programming or architecture. The resulting system is capable of executing a high level user application written in conventional single-system-image form, without the user being aware of the mesh architecture or underlying sensor node hardware. A wireless sensor network is a collection of battery-powered embedded systems that communicate over low-bandwidth radio. Because of their limited hardware, niche deployments and use of embedded processors, programming techniques for wireless sensor network nodes are generally relatively esoteric compared to most software programming tasks. This can be relatively complex for programmers not familiar with the wireless sensor network domain. A naive approach to writing a wireless sensor network application may well result in considerably reduced battery life due to inefficient use of the limited power resources, requiring an expensive and time-consuming replacement or patching process. As a result of this complexity, traditional wireless sensor network applications are written as simply as possible. The majority of these applications simply move passive data readings back across a mesh to a more powerful server. While this is a sufficiently effective approach in some situations, for other sensor network deployments involving large amounts of complex data it is more efficient for the sensor network application to process at least some of the data inside the mesh, saving on unnecessary data transmissions. However in the real world, the complexity of writing such an application in many cases precludes this from being created. An operating system that provides power-efficient distributed processing while presenting a more standard unified single system image to the application developer would provide new possibilities for sensor network application developers in terms of creating dynamic and complex sensor network applications. This thesis covers the design decisions, development process and evaluation of the Hydra distributed wireless sensor network operating system, an operating system that provides these services. The system is evaluated in the form of a scenario for monitoring intruders over a large area using accelerometer monitoring -- during this scenario, power efficiency is gained due to the intelligent Hydra operating system services, as the resulting accelerometer data is not moved across potentially multi-hop network links. Application code complexity is also reduced due to the higher-level single system image programming environment

Requirements on dance-driven 3-D camera interaction: A collaboration between dance, Graphic Design and Computer Science

In this paper we describe our initial ideas towards research investigating dance-driven 3-D-camera interaction as a tool for creating holistic pieces of art for an enriched performance experience. In the first part, we focus on the technical analysis of requirements on a set of input parameters for the dance input. In the second part we explore requirements stemming from the creative themes envisaged. In the discussion we synergize these requirements towards the requirements on a first prototype of the dance-driven 3-D-camera interaction

Low Tech ? Wild Tech !

On ne compte plus aujourd’hui les appels à repenser l’innovation. Il y aurait urgence écologique. Et certains n’hésitent pas à prédire la fin du monde à moins d’une rupture radicale de nos modèles de croissance. Alors que chaque nouvelle génération de téléphone ou d’ordinateur est célébrée comme si elle constituait un progrès décisif pour l’humanité, le low tech à l’inverse, cet ensemble hétérogène de techniques, de modes de composition alternatifs, définis tantôt négativement (pauvreté ou économie des moyens) tantôt positivement (faire beaucoup avec peu de choses, faire avec ce qu’on a, faire plus local et plus participatif, etc.), viendrait partout ébranler la toute puissance du high tech. Avec lui, ce ne sont pas seulement une autre lecture des techniques et d’autres façons de concevoir qui se donnent à voir, mais des populations entières d’hommes et de procédés, dont le rôle a bien souvent été sous-estimé, de l’Inde à l’Afrique en passant par l’Asie. L’objectif de ce numéro n’est pas de cataloguer les formes de résistance ou d’invention très diverses que recouvre l’étiquette de low tech, mais plutôt de poser les bases d’une cartographie alternative des modes d’assemblage à l’échelle planétaire, et de donner des outils pour mieux penser ces manières de fabriquer qui échappent à toute classification : la Wild Tech