Seneviratne says the new technique is important to improve confidence in automatic fire detection systems which can currently sometimes struggle even to differentiate between a fire and a bright flickering neon light. Up to 1,300 packets of data per second can be processed and analyzed. The Wi-Fi sensing system, therefore, amalgamates the effect of the environmental phenomena on all the Wi-Fi subcarrier frequencies and applies data processing to find the most sensitive frequencies which help aid the analysis.
Just as different wavelengths of light are affected uniquely by different objects, different frequencies of Wi-Fi are also impacted in a variety of ways. The new system developed at UNSW exploits the fact that Wi-Fi waves have various transmission frequencies, known as subcarriers. "What we also add into the system is artificial intelligence to analyze all the data and compare to baseline readings to help determine if there is a real fire occurring." Specifically, these signatures are captured in the form of wireless channel information. "Smoke and different gases, such as carbon monoxide that can be produced in fire situations, also affect the density of the air and will give distinctive signatures on our readings. In fact, we have experimentally demonstrated that these changes are strongly correlated with the rise or fall of temperature in the environment between transmitter and receiver. "As the air temperature changes, so does its density, and that changes the signature of the reading when we receive the signal. In conjunction with Trantek MST, the incumbent mission-critical systems vendor for the tunnel, and the tunnel owner/operator, Sydney Harbor Tunnel Company, the researchers set up a series of transmitters and receivers to monitor the environment as a test car prepared for the purpose was detonated and set on fire during a scheduled emergency response training exercise. Seneviratne and his team were able to showcase their new technology during a controlled test in the middle of the night inside the Sydney Harbor Tunnel. The system can then determine with greater accuracy whether any atmospheric changes are being caused by a real fire, and if so, raise an alarm or trigger an automatic sprinkler system.Įxisting detection systems, which are largely based on thermal imaging, often produce false positive readings by detecting levels of smoke or changes in temperature which are not dangerous or caused by an actual fire-perhaps from a faulty exhaust pipe on a vehicle or a hot radiator.īut Prof. The researchers have identified the distinctive patterns in the data from radio signals during fire events, and artificial intelligence within their software helps analyze the environment in real-time. Deepak Mishra, and a team from the School of Electrical Engineering and Telecommunications have designed and built a system that monitors Wi-Fi signals as they pass through the air-and analyzes detailed changes in the environment due to such things as temperature and smoke. Eventually the rest of the world began to use this system, shaping the time zones we know today.Engineers from UNSW Sydney have developed a new fire detection system that could help save lives by monitoring the changes in Wi-Fi signals.Īnd a controlled test detonation of a car, planned by the Sydney Harbor Tunnel Company, recently provided further data to demonstrate the effectiveness of the technology. Other countries created their own standard times and, in the late 1880s, the International Meridian Conference proposed a standardised 24-hour day, starting off at midnight GMT. However, in 1855, the Royal Greenwich Observatory started transmitting time signals and in 1880, the Greenwich Mean Time (GMT) became the country’s official standard time. In 1847, British railway companies began to standardize the time they were using by providing their staff with portable chronometers, resulting in what became known as ‘Railway Time’. A better system was required to enable an efficient operation of railways and new telecommunication systems. Since the time calculations were based on the position of the sun, they could vary by four minutes for each degree of longitude. In the nineteenth century, when mechanical clocks began to become popular, time was calculated locally. Time has traditionally been measured according to the position of the sun in the sky, which is different depending on where you are in the world.
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