Hotline for Drunken Diallers

Drunk and feel like ringing up your ex at some ridiculous hour of the morning? You can guarantee that your call will be unwelcome while you are in your inebriated state. Now, courtesy of the Internet, there is a service that allows you to blurt out all the unintelligible nonsense you like without any shortage of listeners.

The "Works on My Machine" Certification Program

You have to admire the discipline of developers who are so good at keeping within the scope of the task that has been assigned to them. They focus purely on ensuring that their code compiles and executes on their machine. So much so in fact that what has been checked into the repository will not run on anyone else's machine. To recognise such team performers, the Works On My Machine Certification has been conceived.

Formation of a Geometric Pattern with a Mobile Wireless Sensor Network

Justin Lee and Svetha Venkatesh
Department of Computer Science
Curtin University of Technology
Australia

Mohan Kumar
Department of Computer Science and Engineering
The University of Texas at Arlington
Arlington, Texas 76039
USA

Journal of Robotic Systems
Volume 21, Number 10
October 2004

DOI: 10.1002/rob.20033
URL: http://dx.doi.org/10.1002/rob.20033

Abstract

Mobile wireless sensor networks (MWSNs) will enable information systems to gather detailed information about the environment on an unprecedented scale. These self-organizing, distributed networks of sensors, processors, and actuators that are capable of movement have a broad range of potential applications, including military reconnaissance, surveillance, planetary exploration, and geophysical mapping. In many of the foreseen applications, the MWSN will need to form a geometric pattern without assistance from the user. In military reconnaissance, for example, the nodes will be dropped onto the battlefield from a plane and land at random positions. The nodes will be expected to arrange themselves into a predetermined formation in order to perform a specific task. Thus, we present algorithms for forming a line, circle, and regular polygon from a given set of random positions. The algorithms are distributed and use no communication between the nodes to minimize energy consumption. Unlike past studies of geometric problems where algorithms are either tested in simulations where each node has global knowledge of all the other nodes or implemented on a small number of robots, the robustness of our algorithms has been studied with simulations that model the sensor system in detail. The simulations demonstrate that the algorithms are robust against random errors in the sensors and actuators. © 2004 Wiley Periodicals, Inc.

Distributed Motion Coordination for Mobile Wireless Sensor Networks Using Vision

Justin T. C. Lee
Master’s thesis
Department of Computing
Curtin University of Technology
Perth, Australia
March 2003
URL: http://adt.curtin.edu.au/theses/available/adt-WCU20031201.132347/

Abstract

Mobile wireless sensor networks (MWSNs) will enable information systems to gather detailed information about the environment on an unprecedented scale. These self-organising, distributed networks of sensors, processors and actuators that are capable of movement have a broad range of potential applications, including military reconnaissance, surveillance, planetary exploration and geophysical mapping.

In many of the foreseen applications a certain geometric pattern will be required for the task. Hence, algorithms for maintaining the geometric pattern of an MWSN are investigated. In many tasks such as land mine detection, a group of nodes arranged in a line must provide continuous coverage between each end of the formation. Thus, we present algorithms for maintaining the geometric pattern of a group of nodes arranged in a line.

An MWSN may also need to form a geometric pattern without assistance from the user. In military reconnaissance, for example, the nodes will be dropped onto the battlefield from a plane and land at random positions. The nodes will be expected to arrange themselves into a predetermined formation in order to perform a specific task. Thus, we present algorithms for forming a circle and regular polygon from a given set of random positions.

The algorithms are distributed and use no communication between the nodes to minimise energy consumption. Unlike past studies of geometric problems where algorithms are either tested in simulations where each node has global knowledge of all the other nodes or implemented on a small number of robots, the robustness of our algorithms has been studied with simulations that model the sensor system in detail. The nodes locate their neighbours using simulated vision where a ray-tracer is used to generate images of a model of the scene that would be captured by each node's cameras. The simulations demonstrate that the algorithms are robust against random errors in the sensors and actuators. Even though the nodes had incomplete knowledge of the positions of other nodes due to occlusion, they were still able to perform the assigned tasks.

The Tenants of Perth's Prime Office Real Estate

Guess who the main occupants are in Central Park. Here's a clue: they are not the greedy, self-indulgent banks who are charging exorbitant fees simply because they can, finance companies or government departments, as you might expect. Nonetheless, it is hardly surprising, because these companies are enjoying staggering growth that knows no bounds.

Central Park Tenant Profile