Encyclopedia of Computer Science and Technology

Brooks, Rodney 59such as Flickr and YouTube, using the Internet as a substitutefor a traditional phone line (see voip), and even gaming(see online games). Broadband is thus helping drive theintegration of many forms of media (see digital convergence)and the continuous connectivity that an increasingnumber of people seem to be relying on (see ubiquitouscomputing).Further ReadingBates, Regis. Broadband Telecommunications Handbook. 2nd ed.New York: McGraw-Hill, 2002.Bertolucci, Jeff. “Broadband Expands.” PC World (August 2007):77–90.Cybertelecom. “Statistics: Broadband.” Available online. URL:http://www.cybertelecom.org/data/broadband.htm. AccessedJuly 17, 2007.Gaskin, James E. Broadband Bible. New York: Wiley, 2004.Hellberg, Chris, Dylan Greene, and Truman Boyes. BroadbandNetwork Architectures: Designing and Deploying Triple-PlayServices. Upper Saddle River, N.J.: Prentice Hall, 2007.Brooks, Rodney(1954– )Australian, AmericanRoboticistRodney Brooks’s ideas about robots have found their wayinto everything from vacuum cleaners to Martian rovers.Today, as director of the Artificial Intelligence Laboratoryat the Massachusetts Institute of Technology, Brookshas extended his exploration of robot behavior into newapproaches to artificial intelligence.Brooks was born in Adelaide, Australia, in 1954. Asa boy he was fascinated with computers, but it was stillthe mainframe era, and he had no access to them. Brooksdecided to build his own logic circuits from discardedelectronics modules from the defense laboratory where hisfather worked. Brooks also came across a book by GreyWalter, inventor of the “cybernetic tortoise” in the late1940s. He tried to build his own and came up with “Norman,”a robot that could track light sources while avoidingobstacles. In 1968, when young Brooks saw the movie 2001:A Space Odyssey, he was fascinated by the artificial intelligenceof its most tragic character, the computer HAL 9000(see artificial intelligence and robotics).Brooks majored in mathematics at Flinders Universityin South Australia, where he designed a computer languageand development system for artificial intelligence projects.He also explored various AI applications such as theoremsolving, language processing, and games. He was then ableto go to Stanford University in Palo Alto, California, in 1977as a research assistant.While working for his Ph.D. in computer science,awarded in 1981, Brooks met John McCarthy, one of the“elder statesmen” of AI in the Stanford Artificial IntelligenceLab (SAIL). He also joined in the innovative projectsbeing conducted by researchers such as Hans Moravec, whowere revamping the rolling robot called the Stanford Cartand teaching it to navigate around obstacles.In 1984 Brooks moved to the Massachusetts Instituteof Technology. For his Ph.D. research project, Brooks andhis fellow graduate students equipped a robot with a ringof sonars (adopted from a camera rangefinder) plus twocameras. The cylindrical robot was about the size of R2D2and was connected by cable to a minicomputer. However,the calculations needed to enable a robot to identify objectsas they appear at different angles were so intensive that therobot could take hours to find its way across a room.Brooks decided to take a lesson from biological evolution.He realized that as organisms evolved into more complexforms, they could not start from scratch each time theyadded new features. Rather, new connections (and ways ofprocessing them) would be added to the existing structure.For his next robot, called Allen, Brooks built three “layers”of circuits that would control the machine’s behavior. Thesimplest layer was for avoiding obstacles: If a sonar signalsaid that something was too close, the robot would changedirection to avoid a collision. The next layer generated arandom path so the robot could “explore” its surroundingsfreely. Finally, the third layer was programmed to identifyspecified sorts of “interesting” objects. If it found one, therobot would head in that direction.Each of these layers or behaviors was much simplerthan the complex calculations and mapping done by a traditionalAI robot. Nevertheless, the layers worked together ininteresting ways. The result would be that the robot couldexplore a room, avoiding both fixed and moving obstacles,and appear to “purposefully” search for things.In the late 1980s, working with Grinell More and anew researcher, Colin Angle, Brooks built an insectlikerobot called Genghis. Unlike Allen’s three layers of behavior,Genghis had 51 separate, simultaneously running computerprograms. These programs, called “augmented finitestate machines,” each kept track of a particular state orcondition, such as the position of one of the six legs. It isthe interaction of these small programs that creates therobot’s ability to scramble around while keeping its balance.Finally, three special programs looked for signals from theinfrared sensors, locked onto any source found, and walkedin its direction.Brooks’s new layered architecture for “embodied” robotsoffered new possibilities for autonomous robot explorers.Brooks’s 1989 paper, “Fast, Cheap, and Out of Control: ARobot Invasion of the Solar System,” envisaged flocks oftiny robot rovers spreading across the Martian surface,exploring areas too risky when one has only one or twovery expensive robots. The design of the Sojourner Marsrover and its successors, Spirit and Opportunity, would partiallyembody the design principles developed by Brooksand his colleagues.In the early 1990s Brooks and his colleagues begandesigning Cog, a robot that would embody human eyemovement and other behaviors. Cog’s eyes are mountedon gimbals so they can easily turn to track objects, aidedby the movement of the robot’s head and neck (it has nolegs). Cog also has “ears”—microphones that can help itfind the source of a sound. The quest for more humanlikerobots continued in the late 1990s with the development of