When Every Second Counts

by Ami Albernaz

In December 2009, the city of Worcester will observe the 10th anniversary of a fire that destroyed the Worcester Cold Storage warehouse, claiming the lives of six firefighters and leaving a bleak spot on the city's memory. Not long after that somber day arrives, WPI researchers, working closely with the Worcester Fire Department, hope to make available to fire departments everywhere a sophisticated locator system designed to keep such a tragedy from ever happening again.

Several research groups at WPI are developing technologies that have the potential to transform the work of first responders. Learn about three of these technologies on the pages that follow.

A Sense of Place

James Duckworth with a prototype position location transmitter.

For the past five years, a team of five faculty members and several graduate students in the Electrical and Computer Engineering Department has been working to create a fail-safe system that will enable the precise tracking of firefighters. The six men who perished in 1999 could not find their way out of the warehouse, and their comrades outside did not know where to look for them. The system will allow site commanders to continuously monitor firefighters' movements and guide them to safety. It will also include physiological monitoring to indicate if any firefighters' lives are in immediate peril.

"Somebody can make a system that works in one building, but we need something that works well in all buildings."

The position location project is a prime example of WPI researchers harnessing cutting-edge technology to save lives. The current system "would not have been possible in 1999, as technological and fundamental research advancements have helped produce the system we have today," says James Duckworth, associate professor of electrical and computer engineering. With colleagues David Cyganski, Sergey Makarov, William Michalson, and John Orr, Duckworth began working on the system in 2003 with an initial award of $1 million from the National Institute of Justice's Office of Science and Technology.

At the heart of the system are transmitters worn as part of firefighters' turnout gear. The transmitters emit continuous signals that are captured by receivers on fire trucks stationed around the building and streamed to the site commander. As the firefighters move about, lines on the site commander's screen trace their exact locations and paths. Because the system can fix a location in three dimensions, the display shows which floor each firefighter is on. If a particular route becomes impassable, the site commander can direct them to safe exits.

WPI Hosts National Workshops

In August 2008, WPI held the third in a series of national work-shops on the challenges of first responder location and physiological monitoring. More than 100 representatives of industry, government, and academia participated. One day was devoted to trials of three tracking and two homing systems using a scenario devised by the Worcester Fire Department. The photos in this article (including this screen display) show firefighters testing WPI's location and monitoring system.

To enable the communication between transmitter and receiver, the team selected synthetic aperture radar, which uses sophisticated computational methods to extract fine detail from radar signals, and principles from orthogonal frequency division multiplexing, which transmits high-speed data via wired and wireless channels and integrates well with the radio spectrum. The team rejected the Global Positioning System (GPS), as its signals were too weak and bounced off walls, making an accurate location fix impossible.

Tests have shown that the system works well in a variety of indoor environments, though in some newer buildings, metallic window coatings that block ultraviolet light also stop radio signals from getting out. To resolve this problem, the team is considering having first responders deposit repeaters—devices that strengthen radio signals—as they move through a building. "Somebody can make a system that works in one building, but we need something that works well in all buildings," Duckworth says.

Since the project's early days, the WPI team has refined the system with feedback from the Worcester Fire Department. "They've been very reactive to our needs and responsive to our suggestions," says Chief Gerard Dio. "We're happy that someone is paying attention to this problem and has thought about this type of system for us."

Additional Readings

WPI precision personnel locator system: Evaluation by first responders
Cyganski, D., J. Duckworth, S. Makarov, W. Michalson, J. Orr, et al., proceedings of the 20th International Technical Meeting of the Institute of Navigation Satellite Division, Fort Worth, Texas, 2007.

Interactive ultrasound training system
Banker, C. J., P. C. Pedersen, and T. L. Szabo, proceedings of the 2008 IEEE Ultrasonics Symposium, Beijing, China, 2008.

Shining a Light on Vital Signs

Last summer, the research team received a significant boost when it was awarded nearly $1 million from the Department of Homeland Security to integrate physiological monitoring into the system (federal funding for the location research now tops $4 million). Since heart attacks are the leading cause of firefighter deaths, having the ability to keep close tabs on vital signs is critical. The WPI team is evaluating a T-shirt manufactured by Foster-Miller Inc. that picks up heart rate, respiration, and body temperature, along with a pulse oximeter developed at WPI. Held against the forehead by an elastic band, the oximeter shines red and infrared light through the skin with tiny light-emitting diodes and measures how each is absorbed by arterial blood. Readings from the pulsing blood also provide data on heart and respiration rates. Data from the shirt and the oximeter are relayed to the command station by the position location transmitter worn by firefighters.

Since heart attacks are the leading cause of firefighter deaths, the ability to keep close tabs on vital signs is a critical need.

The pulse oximeter, developed by Duckworth and Yitzhak Mendelson, head of the Biomedical Engineering Department, is the product of a long-standing WPI research program in untethered health care. In 2002, a grant from the U.S. Army's Telemedicine and Advanced Technology Research Center (TATRC) spurred WPI scientists to begin work on a multifaceted approach to helping medics expedite care to soldiers in combat. On the battlefield, the pulse oximeter will allow medics to perform remote triage, Mendelson says. Data from the device will be wirelessly transmitted to a small USB-based receiver that a medic can plug into a handheld device or a PC. The device will display each soldier's identifying information along with the physiological data. "If one medic is responsible for 10 to 15 soldiers who are scattered throughout the battlefield, this normally creates a challenge," Mendelson says. "With our system, the physiological data will enable medics to identify the soldiers who need help most immediately, and, in the worst-case scenario, identify soldiers who are already dead."

Worcester firefighter Andy White dons the WPI pulse oximeter sensor before a test of the WPI first responder tracking and monitoring system during a national workshop on campus.

The Air Force Research Lab is currently evaluating the most recent model of the pulse oximeter, which includes advances that surmount a number of technical challenges that Mendelson and Duckworth faced. These include extending battery life (the current model will work continuously for approximately 200 hours) and reducing motion artifacts, or inaccuracies in the data caused by a soldier's movements. "We're anxious to find out how it works in the field and what we still need to do to refine this wearable technology," Mendelson says.

Seizing the Golden Hour

The TATRC funds that advanced the pulse oximeter research also supported the development of a portable ultrasound system that allows rapid diagnosis of injuries. Like the oximeter, it has been refined over the course of several years through testing, evaluation, and feedback from leading military and medical facilities. The display is bright and easy to read in daylight, and the system is easy to operate, even for medics without extensive ultrasound training, who can use it to identify injuries and transmit critical information to doctors. "The goal of the system is to make the most of the golden hour in which severe injuries can still be treated and lives saved," says Peder Pedersen, professor of electrical and computer engineering and director of WPI's Ultrasound Research Laboratory.

Achieving this goal has required long hours of development. "The first challenge," Pedersen says, "was to make a system rugged enough to withstand heat, cold, dust, moisture, and bumpy rides in emergency transport vehicles." As with the pulse oximeter, developing an adequate power supply was a challenge. The latest model can run for a full day without being recharged.

Earlier versions of the system were tested at leading medical institutions, including the Madigan Army Medical Center in Tacoma, Wash., and the University of Massachusetts Medical School, which currently carries the system on its LifeFlight helicopters. Feedback has helped the team of electrical and computer engineering faculty members—Pedersen, Duckworth, and assistant professor Xinming Huang—and a committed crew of graduate students progress toward another goal: making the system as user-friendly as possible.

"The first model was contained in a backpack," Pedersen recalls. "Successive iterations have been increasingly compact; the most recent version can be worn in a vest or carried in a small duffle bag." After experimenting with scanner control by means of voice recognition in place of a keyboard, the researchers decided to use a touch screen, which has so far proven the most efficient way for users to control the display.

They are currently perfecting the system's image-streaming capabilities, hoping soon to be able to transmit real-time video and still Images to doctors following along on a computer screen in the emergency room—or even on a cell phone. The team is also outfitting the latest version with computer-assisted image analysis, which will give the computers the ability to aid in simple diagnoses. In situations where every second counts, advances such as these might well make the difference between life and death.

From Lab to Market

Among the innovative start-ups to have taken root at WPI's Bioengineering Institute is Advanced Body Sensing, which coalesced in 2007 out of research on the pulse oximeter developed by Yitzhak Mendelson (right) and James Duckworth. As president and CEO, respectively, the two researchers lead the company, which is dedicated to refining and marketing the technology. Advanced Body Sensing received funding for the latest version of the pulse oximeter from Planning Systems Inc., an applied technology company. Even as he and Duckworth perfect the sensor for use by soldiers and firefighters, Mendelson is beginning to imagine a host of other potential uses. "We see possibilities for mountaineers, coal miners, and even older individuals with chronic diseases," he notes. Also under consideration are new monitoring features that might someday be incorporated into the device—a carbon monoxide detector for firefighters, for example, or GPS capabilities for elderly users.