College+of+Natural+Sciences
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KAIST Professor Finds Paradox in Human Behaviors on Road
-Strange as it might seem, closing roads can cut delays
A new route opened to ease traffic jam, but commuting time has not been reduced.Conversely, motorists reached their destinations in shorter times after a big street was closed. These paradoxical phenomena are the result of human selfishness, according to recent findings of a research team led by a KAIST physics professor.
Prof. Ha-Woong Jeong, 40, at the Department of Physics, conducted a joint research with a team from Santa Fe Institute of the U.S. to analyze the behaviors of drivers in Boston, New York and London. Their study found that when individual drivers, fed with traffic information via various kinds of media, try to choose the quickest route, it can cause delays for others and even worsen congestion.
Prof. Jeong and his group"s study will be published in the Sept. 18 edition of the authoritative Physical Review Letters. The London-based Economist magazine introduced Prof. Jeong"s finding in its latest edition.
Prof. Jeong, a pioneer in the study of "complex system," has published more than 70 research papers in the world"s leading science journals, including Nature, PNAS and Physical Review Letters. "Initially, my study was to reduce annoyance from traffic jam during rush hours," Prof. Jeong said. "Ultimately, it is purposed to eliminate inefficiency located in various corners of social activities, with the help of the network science."
The Economist article read (in part):
"...when individual drivers each try to choose the quickest route it can cause delays for others and even increase hold-ups in the entire road network.
"The physicists give a simplified example of how this can happen: trying to reach a destination either by using a short but narrow bridge or a longer but wide motorway. In their hypothetical case, the combined travel time of all the drivers is minimized if half use the bridge and half the motorway. But that is not what happens. Some drivers will switch to the bridge to shorten their commute, but as the traffic builds up there the motorway starts to look like a better bet, so some switch back. Eventually the traffic flow on the two routes settles into what game theory calls a Nash equilibrium, named after John Nash, the mathematician who described it. This is the point where no individual driver could arrive any faster by switching routes.
"The researchers looked at how this equilibrium could arise if travelling across Boston from Harvard Square to Boston Common. They analysed 246 different links in the road network that could be used for the journey and calculated traffic flows at different volumes to produce what they call a “price of anarchy” (POA). This is the ratio of the total cost of the Nash equilibrium to the total cost of an optimal traffic flow directed by an omniscient traffic controller. In Boston they found that at high traffic levels drivers face a POA which results in journey times 30% longer than if motorists were co-ordinated into an optimal traffic flow. Much the same thing was found in London (a POA of up to 24% for journeys between Borough and Farringdon Underground stations) and New York (a POA of up to 28% from Washington Market Park to Queens Midtown Tunnel).
"Modifying the road network could reduce delays. And contrary to popular belief, a simple way to do that might be to close certain roads. This is known as Braess’s paradox, after another mathematician, Dietrich Braess, who found that adding extra capacity to a network can sometimes reduce its overall efficiency.
"In Boston the group looked to see if the paradox could be created by closing any of the 246 links. In 240 cases their analysis showed that a closure increased traffic problems. But closing any one of the remaining six streets reduced the POA of the new Nash equilibrium. Much the same thing was found in London and New York. More work needs to be done to understand these effects, say the researchers. But even so, planners should note that there is now evidence that even a well intentioned new road may make traffic jams worse."
2008.09.18 View 14480 -
Prof. Kim Receives Lee Osheroff Prize
Professor Eun-Seong Kim of the Department of Physics has been selected as the winner of the Lee Osheroff Richardson Prize for 2008.
The award was established in honor of the 1996 Nobel Prize laureates in Physics David Lee, Douglas Osheroff, and Robert Richardson for their discovery in superfluidity in helium-3. The annual prize sponsored by Oxford Instruments NanoScience is awarded to a young scientist who has made a notable achievement in the field of low temperatures and high magnetic fields.
Kim was chosen as the winner of this prestigious award for his contributions to the understanding of solid helium. Through research, Professor Kim found superfluid-like behavior in solid helium and with this discovery it is shown that all three states of matter can exhibit superfluid behavior.
The Lee Osheroff Richardson Prize recipient is selected by the North American Prize Committee which is composed of prominent figures in the low temperature and high magnetic fields including Professor Bruce Gaulin of McMaster University, who chairs the Prize Committee. The award ceremony was held on March 11 in New Orleans.
2008.03.18 View 13950 -
Professor Jie-Oh Lee of the Department of Chemistry of KAIST
Professor Jie-Oh Lee of the Department of Chemistry of KAIST was selected as the "KAIST Man of the Year."
Lee was cited for his successful identifying of the three-dimensional structure of protein that causes sepsis. His research is expected to contribute greatly to the development of medicines for immune system treatment.
The prize was given by KAIST President Suh Nam Pyo at the New Year"s ceremony on Jan. 2, 2008 at the KAIST auditorium.
Professor Lee published a series of research papers in Science, one of the world"s most prestigious scientific journals. Most recently, Lee was awarded the "Scientist of the Year" prize by the Korean Science Reporters Association.
2008.01.02 View 14479 -
Professor Jie-Oh Lee awarded 'Scientist of the Year'
Professor Jie-Oh Lee of the Department of Chemistry was awarded the ‘Scientist of the Year’ prize for identifying the three-dimensional structure of protein that causes sepsis, and it was announced by the Korean Science Reporters Association (KOSRA) on November 26th.“Humans have about 30,000 different kinds of proteins, and they all have different structures, just like our faces,” said Professor Lee. “It is extremely helpful to know the three-dimensional shape of proteins when you are trying to understand what their functions in an organism are and trying to develop medicine for them.”
When looking for the three-dimensional structure, protein must first be crystallized and radiated with x-ray, so that reflected x-ray can be interpreted. The three-dimensional structure of sepsis immunity proteins TLR1-TLR2 and TLR4-MD2 could not be found until now because they would not even crystallize.
“I began to doubt if it was even possible to crystallize them because we went through so many failures,” reflected Professor Lee.
In August of last year, after about three years of research, the team finally came up with a new idea. The team decided to ‘stick’ the sepsis immunity protein to protein that easily crystallizes. If the combined structure of sepsis immunity protein and the known protein could be identified, the structure of sepsis immunity protein would be a combined structure subtracted by the known structure.
The three-dimensional structure was obtained with x-ray radiation from combined protein crystal. The combined protein was derived from an insect cell with altered DNA.
“This method seems very simple but no one ever tried it or no one ever succeeded in it,” said Professor Lee.
The result was a horseshoe shaped protein structure. The research team also expects the new protein-combining technology to contribute to the development of a new immune system treatment medicine.
The prize-awarding ceremony was held on November 26th in an event hosted by the Korean Hospital Association.
Also, Professor Ryong Ryoo of the Department of Chemistry was selected as the National Scientist last month.By KAIST Herald on November, 2007
2007.12.21 View 14011 -
Professor Churchill listed on international biographical dictionary
Professor Churchill listed on international biographical dictionary
Professor David G. Churchill (Department of Chemistry) is listed in Who’s Who in the World in its edition for 2007, international biographical dictionary published by Marquis Who’s Who.
Professor Churchill majored in Organometallic Chemistry and Chemistry of Complex at Colombia University in U.S. and began lectures at KAIST Chemistry department in July 2004.
Professor Churchill has presented 56 papers as member of the American Chemical Society and the Korea Chemical Society and is recognized for his excellent research performances. Recently, he is studying on a method to sense and counteract various toxic nervous substances by bonding them with metals.
2006.11.08 View 17318 -
Professor Chung-Seok Chang named as APS Fellow
Professor Chung-Seok Chang named as APS Fellow
- Honorable position offered only to an extremely small number of members within 0.5% of APS
- Recognized for his leading and creative contribution to Plasma conveyance theory, Electromagnetic waves heating theory and leadership in the research field of large-scaled computer simulation
Professor Chung-Seok Chang (Department of Physics) was named as a fellow of the American Physics Society (APS), world-renowned society in the physics filed.
The fellow of the APS is considered as a position of great honor among scholars in the field of Physics since only a small number of regular members within 0.5% of the APS can become the fellows. Professor Chang was recognized for his leading and creative contribution to the fields of Plasma conveyance theory, Electromagnetic waves heating theory and leadership in the research field of large-scaled computer simulation, which made him named as APS fellow.
Professor Chang has been invited several times to the Main Policy Committee of the U.S. Department of Energy and was a member of On-site Review Committee on the theoretical research activities of the U.S. major state-run institutes. Due to many world-recognized research results carried out with KAIST students, he has been invited several times for lecture to the conference of the APS as well as large-scaled international academic conferences. As a result, KAIST doctorates of Computational Physics from his laboratory are recognized globally for their excellence in the field of nuclear fusion.
Besides, Professor Chang was assigned as the Chief General of the super-sized Computational Theory Research Group last year, to which the U.S Department of Energy will invest 6 million dollars of research fund for three years, and manages the complex theory research group that transcribes and reproduces the properties of nuclear fusion plasma by using large-scaled parallel computers with its head quarter in the U.S. Courant Institute of Mathematical Sciences. This research group consists of greatest U.S. scholars in the fields of Physics, Mathematics, and Computation, belonging to 14 research-education institutes such as Princeton University, Colombia University, MIT, University of California Engineering College, California State University, Rutgers University, New-York University, Courant Institute of Mathematical Sciences, Oak Ridge National Lab, Berkeley National Laboratories, etc., thereby gathering worldwide
2006.10.25 View 13932
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Professor Ryong Ryoo, selected as a scientist wished to resemble and to be 2006
Professor Ryong Ryoo, selected as a scientist wished to resemble and to be 2006
Professor Ryong Ryoo (Department of Chemistry) was selected as a scientist wished to resemble and to be 2006.
Professor Ryoo developed in 2000 world’s first nanoporous carbon material in which numberless several nanometer-sized holes were drilled. The development of this nanoporous material was introduced by international scientific journal NATURE in 2000 and 2001 and expected to contribute to the progress of mankind through the development of high efficiency fuel cell or ultra-light computer. Professor Ryoo also developed a new technology that can considerably improve the catalyst activation and stability of ‘Zeolite’, a main catalyst in the petrochemical industry, which was introduced by NATURE materials. The above achievements qualified Professor Ryoo for the selection.
‘Scientists wished to resemble and to be 2006’ were selected among scientists showing vigorous activities in the science and technology circle on the basis of their recent achievements, etc. by the Ministry of Science and Technology and the Korea Science Foundation, and total 10 scientists qualified to be the model of children and the youth were announced on August 24.
2006.09.06 View 15610
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Nobel Laureate Heads KAIST
Nobel Laureate Heads KAIST
By Kim Tae-gyu / Staff Reporter
THE KOREA TIMES 05-29-2004
A Nobel laureate will lead the Korea Advanced Institute of Science and Technology (KAIST), winning a stiff race with a pair of strong Korean candidates.
The KAIST on Friday said the state-financed institute appointed Robert Laughlin as its 12th president instead of two local hopefuls, professors Shin Seong-cheol and Park Seong-ju.
This is the first time that foreigners take charge of the KAIST since it was established in 1971 and Laughlin also is noted in the history as the first Nobel Prize winner to head Korea"s educational institute.
After receiving approval of Science-Technology Minister Oh Myung, Laughlin will be inaugurated as early as next month, according to a KAIST official.
Laughlin, a Stanford professor, made his name after being co-awarded the 1998 Nobel Prize in Physics with Horst Stoermer and Daniel Tsui for the discovery of a new form of quantum fluid.
The findings, which explained the fractional quantum hall effect for the first time, have been recognized as a significant breakthrough in understanding quantum physics.
The American physicist had also sustained a special connection with Korea even before he garnered the prestigious prize and has visited Korea several times.
Early last month, Laughlin was named to head the Asia Pacific Center for Theoretical Physics (APCTP) in recognition of his notable interest in Korea.
The APCTP is an international research institute headquartered inside Pohang University of Science and Technology in North Kyongsang Province.
voc200@koreatimes.co.kr
2004.05.31 View 18833