Research
Penn State Intercom......April 30, 2001

'Talking' helps computer programs
develop better hunting strategies

By Barbara Hale
Public Information

An NEC Institute/University study shows that computer programs, known as autonomous agents, not only can evolve their own language and talk with one another, but also can use communication to improve their performance in solving the classic predator-prey problem.

Like kids playing hide and seek, the autonomous agents used in the study hunted for and found their prey faster and more efficiently if they communicated with one another. "Talking," via a message board, enabled the agents to perform better than in all previous predator-prey studies -- better even than when they had been programmed with a hunting strategy by humans.

C. Lee Giles, the David Reese professor of information sciences and technology and co-author of the study, said, "The findings have a number of possible applications, for example, smart Web crawlers that communicate with one another as they scour the Web automatically retrieving information. One can also imagine military applications or intelligent robots that explore other planets or the sea bed in groups while talking to one another."

The research was performed when Giles and co-author Kam-Chuen Jim were both at NEC Research Institute Inc. Jim is currently at Physiome Sciences Inc. Giles joined the University's new School of Information Sciences and Technology in fall 2000.

In the study, four predator agents inhabiting a virtual, four-sided, two-dimensional-grid world, were set in pursuit of a fifth agent who served as the prey. The agents all moved simultaneously, at the same speed in north, south, east or west directions. No diagonal shortcuts were permitted. The predators could not see each other and did not know each other's location.

The researchers write that this scenario is probably more difficult for the predators than any considered in previous studies of the predator-prey problem.

The predator agents' goal was to capture the prey by surrounding it on all four sides. Each of the predator agents could "speak" a short string of zeros and ones, the binary alphabet, simultaneously. The communicated strings of symbols were placed on a message board. Each agent could then read all the strings communicated by all the predators in order to determine the next move and what to say next.

The researchers explain that the agents created their own vocabulary, the strings of zeros and ones, in a random manner.

Self-organization into meaningful "language" occurred because the agents are coupled in the sense that they must conform to a common vocabulary in order to cooperate through communication. Since the predators cannot see each other and do not know each other's location, the predators have to evolve a language that can represent such information.

The researchers found that as the size of the language increased, the performance of the predators improved. Using this observation, the researchers developed a method for incrementally increasing the language size that results in a coarse-to-fine search that significantly reduces the time required to find a solution.

The researchers wrote that "Future work could focus on the semantics of the evolved languages."

Barbara Hale can be reached at bah@psu.edu

Parental influence key to
how teen siblings behave

By Vicki Fong
Public Information

Parents of teen siblings exert a greater influence than previously believed on the relationship between two youths and the amount of fighting between them, says a new study.

"One theory about why parents respond in the ways they do to sibling conflict holds that parents react to their children's personality styles," said Susan McHale, professor of human development and family studies and one of the study's researchers. "We found no evidence to support this theory."

The researchers studied 185 white-American, working and middle-class families with first-born youths averaging age 15 and the second-born averaging age 13.5. The team examined two forms of parents' direct involvement in their teen children's sibling relationships: the amount of time parents spent together with their two children and the ways in which parents intervened in the sibling conflicts.

McHale, Kimberly Updegraff of Arizona State University, Corinna Tucker, the University of New Hampshire, and Ann Crouter, University professor of human development and family studies all worked on the project.

Past research says that teen-agers grow more detached from family members and are more oriented to peers and popular culture, but this study finds that the time parents spend with their teens matters: The best predictor of a warm sibling relationship that was low in conflict was the amount of time mothers and fathers spent in the company of their two teen children.

The study also found that parents who see autonomy as more important -- for example in their workplace experiences -- were less likely to be harsh and punitive when responding to sibling conflict, and their children fought less often.

Vicki Fong can be reached at VFong@psu.edu

Declining mental skills
can catch you off guard

By Barbara Hale
Public Information

As if having recognizable absent-minded moments isn't bad enough, now University re-searchers say that we may lose some basic mental skills and not realize it.

In a study of 15 normal, healthy aged men and women that is the first of its kind, the researchers found that the subjects were unable to accurately estimate their prowess at reading maps, remaining attentive and pantomiming tool use. The subjects were accurate in estimating their memory and several others functions such as mood and vision. Dr. Anna Barrett, assistant professor of medicine and neurology in The College of Medicine and the study's principal investigator, said "The research shows that there were some areas where these normal, healthy people were unaware that their perception of their performance on some very basic mental skills didn't match their actual competence. In other words, they were unaware that they weren't performing at the level they thought they were.

"If people are unaware of their level of performance, they can't take countermeasures or seek assistance when these skills decline. Caregivers and partners need to be alert to the signs of mental loss or decline in completely normal individuals and be sensitive to the fact that the person suffering the loss may be completely unaware of it," she added.

Kerri A. Hansell, an undergraduate at Lebanon Valley College, served as a
research assistant on the project. Dr. Paul J. Eslinger, professor of medicine and neurology; Dr. J. Kenneth Brubaker, neurologist at the Masonic Home, Elizabethtown; and Dr. Kenneth M. Heilman, professor of neurology, University of Florida, College of Medicine, were the co-researchers.

Although the test sample was small, Barrett says that the results are statistically significant. The researchers are now conducting the same tests with subjects who are victims of Alzheimer's disease.  

Barbara Hale can be reached at bah@psu.edu

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