Experiment Setup
Wizard of Oz study of indoor positioning technologies at Paris training house, March 2007
We started our work by exploring the use of location information in reconnaissance missions. In a training facility of the Paris Fire Fighting Brigade we ran seven simulated reconnaissance missions with teams of up to eight fire fighters. The missions were run in a building specially designed for training and the fire-fighters were equipped with the complete required equipment for such missions, including protective clothes and breathing apparatuses. To simulate null visibility conditions, we placed a layer of paper in the breathing masks, thus blocking sight, but allowing a rough recognition of light sources. The mission in every case was a reconnaissance mission which consisted in walking through the building and finding bottles of water that were previously hidden by members of the team.
To obtain indoor positioning, we constructed a Wizard of Oz prototyping platform. One facilitator was assigned to each and every fire fighter in the mission. He captured the actual position of the fire-fighter by clicking on a map of the building shown on a piece of software specifically designed for the task. This information was transmitted using a wireless network to a central computer mounted on a command post, where visualization on our command post application allowed following the position of the tracked fire fighter in a Large Interactive Display (Figures below).
- Entering of positioning data by human facilitator
- Command Post Application
Command Post Application, December 2006/ March 2007
We see the command post application not as a product prototype but as a useful tool for visualizing data coming from different wearable and other sensors (e.g. electronic lifeline prototype, PDR, wearable heart rate sensors). The experiences from the evaluation flow into the application design for our March evaluation on simulated indoor positioning with Paris fire fighters. The first prototype of the system was presented in our workshop in March of 2007 in Paris and received positive feedback. As described above, the prototype was used in several training exercises that presented indoor positioning alternatives to the fire fighters.
- Relate sensor node on the strap of the fire fighter’s air tank
PDR positioning component
A first evaluation of the PDR positioning prototype has been conducted at the TZI office building in Bremen, Germany. The evaluation involved taking position measures on a known path and comparing measured with actual position information.
Networking Component
The networking component was evaluated during our user study in Paris in March 2007. Here the networking component was used to connect our Wizard of Oz platform with the command post application showing positioning information. A second test took place during a live demonstration at the Internal Review in June. Here, wireless routers in meshed configuration with the AODV network protocol were used. Thirdly, at the University of Bremen a per-formance evaluation of multipath ad hoc transmission with packet duplication was conducted.
Sensor Network LifeNet
At the time of the evaluation in March, the navigation application based on the sensor nodes from the Relate project was not yet functional. The objective of the March study was to obtain a reference measurement of the positioning provided by the sensor nodes during training exercises of search and rescue missions. As can be seen in the figure below, a fire fighter was equipped with sensor nodes, notably with a customized sensor node, where the ultrasound transducers had been integrated into the sole of the boots while the rest of the sensor node was mounted on the back of the boot. Additionally, sensor nodes where distributed over the floor of the training house where the intervention took place, following a preestablished and accurately measured pattern. This was done to obtain a ground truth to which to compare the measurements of the sensor nodes. Also, the obviously somewhat imprecise measurements obtained through the Wizard of Oz system where used to validate these measurements.
Virtual Reality Simulation FireSim
The purpose of FireSim is to be able to evaluate wearable applications in a sufficiently realistic way to obtain design-relevant feedback but long before physical systems become avail-able or can be produced in sufficient numbers. Another design goal of FireSim is to support continuous and numerous evaluations in a playful manner. For this reason, the simulation is designed to run on standard gaming PC-hardware available and used in many fire stations. Also it is intended to be sufficiently motivating and easily usable.
The version of FireSim tested during the March evaluation offered a single player a simulation of the LifeNet and provided a simple early version of arrow-based navigation support on a physical HMD that was integrated into a physical breathing mask and could be worn during the simulation. The application producing the interface on the HMD retrieved the required information from the virtual environment, providing the fire fighter with interactive feedback about his actions on the actual wearable system.
- Virtual Reality Simulation FireSim
