PHILADELPHIA - Computer scientists at the University of Pennsylvania and other institutions have received a $2.84 million grant to boost the dependability of the specialized minicomputers embedded in electronic devices from toasters to passenger jets.

The three-year award, from the U.S. Department of Defense Army Research Office, brings external funding awarded to Penn embedded systems research group within the last 18 months to more than $6 million.

Principal investigator Insup Lee will lead a team of researchers from Penn, Georgia Southern University, New Jersey Institute of Technology and the University of Michigan.

"These tiny embedded computers can literally make the difference between life and death, so their reliability is crucial," said Lee, professor of computer and information science at Penn. "Even though theye small, these computers are growing more complex, meaning the number of problems that can develop in them is also growing."

Lee and his peers will examine ways to engineer reliability and reusability into embedded computerssoftware during the earliest stages of design. Among their goals: developing an integrated approach to development of reliable embedded systems that takes into account real-time issues and re-source constraints the system will face, such as energy consumption, memory size and weight of the final product.

Embedded computers are ubiquitous, found in products ranging from dishwashers to automobile transmissions to cellular phones. They underpin much of modern medicine; equipment like heart-lung machines, infusion pumps, defibrillators, dialysis machines and mammography machines are all rife with embedded systems.

New automobiles can house a dozen small computers, each regulating key functions such as antilock braking systems and engine performance. Air traffic control systems and the machinery that monitors nuclear reactors are also packed with the specialized processors, most of which operate very rapidly in response to continuously changing input.

"Embedded systems are becoming increasingly networked, meaning the failure of one can cause many others to fail," Lee said. "Much of the concern a few years ago about the 2K bugreflected uncertainty over what might happen to the computers found not on our desktops but in the many electronic devices that surround us."

Embedded systems are thornier to build than most other computers because they exist at the interface of several different engineering disciplines. Computer scientists develop the software to run the systems, but embedded computersrapid operation under continuously changing conditions - think of the computer that decides what gear a car should be in at any given moment - also demands expertise in control theory.

Lee Penn colleagues on the ARO grant include Rajeev S. Alur, Carl A. Gunter and Sampath Kannan, each a professor of computer and information science, and Oleg Sokolsky, research assistant professor of computer and information science. Others on the project include Robert P. Cook at Georgia Southern, Elsa Gunter at NJIT and Kang G. Shin at Michigan.