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News Tip


June 17, 2003

For more information on these science news and feature story tips, contact the public information officer listed at (703) 292-8070. Editor: Josh Chamot

Grid Community Pulls Together to Battle SARS in Taiwan

Photo of developers in front of large screen.
Developers at the NCHC Access Grid node test the SARS Grid network links.
Photo Credit: National Center for High-performance Computing, Taiwan
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Grid computing researchers around the Pacific Rim have mobilized to fight the SARS epidemic, helping establish a cutting-edge communication grid among quarantined hospitals across Taiwan. In addition to linking the hospitals to each other, the grid connects doctors to global sources of health information.

On May 15, in search of expertise for setting up Access Grid sites, Taiwan's National Center for High-performance Computing sent a request to members of the Pacific Rim Applications and Grid Middleware Assembly (PRAGMA). Led by the San Diego Supercomputer Center at the University of California, San Diego, offers of assistance poured in from all PRAGMA sites within hours, including Argonne National Laboratory where the Access Grid was developed.

"National Science Foundation (NSF) support for the PRAGMA partnership has led, most importantly, to the development of strong human trust and a cooperative spirit among the sites," said William Chang, NSF program manager in the Office of International Science and Engineering. "PRAGMA shows that NSF's investment in cyberinfrastructure will transform not only scientific research and learning but also the handling of global episodic events such as SARS," he added.

Because quarantine and isolation are the primary means of slowing the spread of SARS, Taiwan's hospitals faced a communication logjam. Physicians in quarantined hospitals were unable to consult with specialists at other institutions, and on a more personal level, hospital staff and patients had limited contact with their families.

The Access Grid, a network-based collaboration environment, goes beyond standard video- and teleconferencing and allows physicians to share detailed X-ray images, patient data and other information in on-line meetings among several sites. The Access Grid can also host private virtual rooms for patients or hospital staff to visit with family members.

PRAGMA members gathered June 5-6 in Australia for the fourth PRAGMA meeting to discuss how they might expand the Taiwan experience and extend the SARS Grid to other locations in the Pacific Rim.

"Thanks to PRAGMA, the alliance has been formed," said Fang-Pang Lin, director of the NCHC's grid computing division. "NCHC has a responsibility to assist in handling this arduous task, and with assistance offered from the international grid community," says Lin, "we believe that we can adequately contribute to the nationwide call to assist in fighting the disease, relieving the epidemic, and ultimately save many lives." [David Hart]

NSF Media Contact: David Hart, (703) 292-7737,
NSF Program Manager: William Chang, (703) 292-8704,
Principal Investigators: Peter Arzberger, UCSD, (858) 822-1079,
Phil Papadopoulos, SDSC, (858) 822-3628,
Fang-Pang Lin, NCHC,

NCHC SARS Combat Task Force:
Access Grid:

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Scientists are Monitoring Potentially Toxic Blue-Green Algae in Wisconsin Lakes

Scientists at NSF's North Temperate Lakes Long-Term Ecological Research (LTER) site are gearing up this summer to monitor an exotic blue-green algae that has been migrating northward in the United States. In recent years, the organism has been detected as far north as lakes in Madison, Wisc.

While commonly called a blue-green algae, it is actually a cyanobacterium known as Cylindrospermopsis raciborskii, or "Cylindro." Originally identified in Brazil, Cylindro and has been found in several southern states as well as in Illinois, Indiana, Michigan, Minnesota and Ohio. Biologists don't know how the organism arrived in Wisconsin, but say it could have been transported here by a migratory bird or by hitching a ride on boats, boat trailers or other water-recreation gear from infested waters.

Starting in late July and extending through September, scientists at the NSF LTER site and affiliated with the University of Wisconsin at Madison, along with researchers at the Wisconsin Department of Natural Resources, will collect water samples from Madison-area lakes.

Cylindro is common in Wisconsin lakes, and can reach concentrations during summer that cause nuisance blooms on the water's surface. These blooms make swimming and other water-recreation unappealing. Some cyanobacteria can produce natural toxins that are short-lived but may pose health risks to wildlife, pets, livestock, and even humans if the organisms are present in high concentrations. Cylindro is one of the most toxic, releasing both neurotoxins and liver toxins into drinking water. It is responsible for human health problems and water supply problems in tropical and subtropical areas.

Researchers at the LTER site routinely sample water quality in Madison-area lakes as part of a long-term monitoring project to better understand and chart changes in the lakes. Counts of microorganisms from the lakes Mendota and Monona over the past few years have shown researchers that Cylindro is present in low concentrations during late summer.

In the process of checking microscopic slides for samples collected from Lake Wingra last summer, researchers found the species was in much higher concentrations than seen in Lakes Mendota or Monona. As a result, LTER scientists are now examining archived microorganism samples collected from Lake Wingra from past years to determine whether Cylindro was present and to what extent.

However, most of the work in coming months will focus on trying to understand the distribution of Cylindro in Wisconsin's eutrophic lakes—environments which either naturally or as a result of man-made pollution are rich in nutrients such as phosphorus that can spur overproduction of organic material. [Cheryl Dybas]

NSF Media Contact: Cheryl Dybas, (703) 292-7734,
NSF Program Manager: Henry Gholz,
Principal Investigator: Steve Carpenter,

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A Surveillance System for Cybersecurity Attacks

Computer forensics remains as much art as science, because savvy hackers can erase their virtual fingerprints from the crime scenes. To reconstruct such crimes, new cybersecurity research from the University of Michigan has created a surveillance system that records an intruder's every move.

"What we have created is a way to watch history unfold exactly as it did before," said Peter Chen, associate professor of electrical engineering and computer science at the University of Michigan. "Not only can we rewind an attack to undo the damage, we can also replay any point during the attack to observe exactly how the intruder breached the system."

Developed by Chen and his students with NSF support, the ReVirt surveillance system allows a forensic analyst to dissect, and even undo, each step taken by a computer intruder. ReVirt can show the intruder's method of breaking and entering and any efforts to cover his or her tracks.

While various systems exist for logging the actions of computer intruders, these systems have two failings. First, they assume the computer's operating system is trustworthy, which is not the case when a computer has been compromised. Second, even if the intruders forget to cover their tracks, the systems do not log enough low-level detail to know precisely what transpired.

To address these issues, ReVirt runs a virtual computer within a computer. The virtual computer emulates the hardware of the host computer, and all users and unsuspecting intruders do their work on this virtual machine. However, ReVirt's surveillance system operates from the host computer, walled off from the virtual machine, and records enough information to replay every instruction executed by the virtual computer. ReVirt can "see" the intruders, yet the intruders do not know they are being watched.

Legitimate users do not notice the extra security because ReVirt adds minimal overhead to the system's operation. According to Chen, system administrators could store several months of logging traffic from typical workloads on a single 100-gigabyte disk. Chen's group now plans to build additional security services on top of ReVirt, including automatic diagnosis of and recovery from an attack. [David Hart]

NSF Media Contact: David Hart, (703) 292-7737,
NSF Science Expert: Carl Landwehr, (703) 292-8936,
Principal Investigator: Peter Chen, (734) 763-4472,

The CoVirt Project:

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