Step forward

An MIT researcher has invented a robot that learns to walk like a human toddler, stepping each leg forward and gradually improving its balance. As the machine gains more skill, it adapts its gait to the surrounding terrain. Scientists say the technology may help them better understand human motor movement and lead to improved prostheses.

Russ Tedrake, the postdoctoral associate who calls his invention "Toddler," says his robot can learn to walk in 20 minutes. Special sensors take measurements 200 times every second, checking motion, speed, and tilt, then send instructions to motors and springs that control movement. Each arm moves in sync with the opposite leg to maintain balance.

Toddler is the size of a real baby, about 17 inches tall and about nine pounds, with a Pentium chip in his belly and batteries in his ankles. The experimental biped uses a fraction of the energy used by other walking robots that employ motors to control every action, giving the new machine an extra dose of practicality.

Toddler emerged from several years of study in what researchers call "passive-dynamic design," which was originally inspired by walking toys that date back to the 1800s.

Rapid returns

The IRS expects this will be a record year for electronic filing, projecting that e-filing will account for over half of all returns.

The agency expanded its free filing program this year, offering free software tools to most taxpayers. The system works in conjunction with 15 software companies, which set their own qualifications (such as age, income, or military service) for free usage.

Among paid preparation products, Intuit's TurboTax program remains the dominant software package, selling nearly 5.9 million copies through early April. Its major competitor is H&R Block's TaxCut, which offers similar features, often at a lower price.

IRS officials, who claim e-filing speeds up refunds and helps catch common errors, hope taxpayers will beat last year's record of 62 million e-filed returns. They face a congressional mandate that 80 percent of returns be filed electronically by 2007.

The IRS also hopes to avoid the last-minute glitches that hit just before last year's April 15 filing deadline, forcing it to switch to a backup system for accepting electronic returns. The agency also plans to eliminate TeleFile, a program that offers filing by phone, after this year, citing declining demand.

Bits & Megabytes

· Nissan showed off a prototype car that automatically returns to its lane if the vehicle starts veering away. Other "smart car" features include a video-guided parking system and a dashboard monitor that simulates an aerial view of the car. The Japanese automaker has not announced when it will launch these systems.

· Microsoft recalled over 14 million Xbox power cords after 30 users complained about fire damage. The software giant says seven people burned their hands and another 23 reported smoke damage or damage to their carpets or entertainment centers. Microsoft warns customers to switch their Xboxes off when not in use and offers free replacement cords at www.xbox.com.

· A new virus that attacks mobile phones reached the United States, targeting Bluetooth connections. Nicknamed Cabir, it poses as an incoming text message to coerce the user into installing a program that looks for other vulnerable devices. Users can avoid this intruder by adjusting the Bluetooth phone setting to "hidden," which blocks scanning by other handsets.

· European airplane maker Airbus will enable cell-phone calls and internet access on its new superjumbo A380 jets. A Swiss company called OnAir signed a deal to provide the technology, which airlines can buy as an option, and plans to charge from $2.00 to $2.50 per minute. Airbus still needs approval from E.U. and U.S. regulators; the FCC is reconsidering its ban on in-flight mobile-phone use.