Johns Hopkins Magazine -- February 2001
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S C I E N C E    &    T E C H N O L O G Y


Making cyberspace a more secure place
Plumbing the palimpsest
The end is NEAR
Limacons and spirals on the move
A watery view of bone development

Making cyberspace a more secure place

Hackers beware.

Hopkins, poised at the true turn of the millennium, is launching a new research effort called the Information Security Institute (ISI) to examine legal, ethical, technological, and security issues linked to cyberspace. Faculty across campus will offer seminars and course work starting later this year. The institute is funded in part by a $10 million seed gift from an anonymous donor.

"These are issues that have taken center stage in our society over the past decade and will only grow in importance as technology continues to advance," says Hopkins President William R. Brody, who announced the institute in early December.

Illustration by James Yang
Concerns over break-ins at top government and corporate computer networks and other cyber-security issues have long concerned academics and business types alike. The new institute, to be staffed by 50 faculty members from across the university, will focus on a range of problems plaguing the Internet universe: from the security of e-business transactions, to questions about patient privacy in medical databases, and ethical quandaries about how to best protect intellectual property and copyrighted material online.

Tapping a growing information technology economy in the Washington-Baltimore area, Hopkins also plans to offer courses to undergraduates and graduate students to prepare them for a burgeoning new field. Part training, part lucrative contract work, a new institute-created lab will allow researchers and students to test security vulnerabilities in software and hardware systems supplied by government or corporate clients.

The institute, administered through the Whiting School of Engineering, will use such contract revenue streams and grants to hire as many as 30 researchers over the next three years, administrators say. Much of the research will expand on work already being done across the university. The Applied Physics Lab, for example, has contracts worth millions of dollars annually to conduct information security-related research; the Nitze School of Advanced International Studies has held two international conferences in the past year on global cyberspace issues, including security.

Gerald Masson, chair of the Department of Computer Science, is serving as interim director: "This is one of those windows of opportunity that comes by rarely," Masson says. "You can either charge through it or watch it pass by, but it's not going to stay open long. The infrastructure is here at Johns Hopkins to make this work." --Joanne Cavanaugh Simpson

Plumbing the palimpsest

It is an old, musty book, its parchment crumbling and edges charred. But this decaying relic, which is carefully ensconced in the climate-controlled back rooms of the Walters Art Museum in Baltimore, is a priceless treasure.

The 7 1/2 inch x 6 inch book is a palimpsest, or twice-used parchment book. Its pages, on their surface, contain 12th-century Greek Orthodox prayers and rites. But beneath the liturgy are barely visible writings of the ancient Greek mathematician Archimedes, scribed in the 10th century.

Christens-Barry (back) examines the palimpsest.
Photo by Louis Rosenstock
Now, a team of imaging specialists led by Hopkins physicist William Christens-Barry and researchers at the Rochester Institute of Technology are using state-of-the-art imaging tools to recover the underlayer of the 174-leaf volume. In a first phase of the project, the researchers recently examined five leaves of the palimpsest. The analysis revealed that the pages contain "On Floating Bodies," Archimedes' treatise on buoyancy, one of his most famous works. The treatise and two others in the palimpsest are the only copies of these works penned in Greek.

The technology is working exceedingly well, says William Noel, associate curator of rare books and manuscripts at the Walters. "The results are fantastic. They've exceeded all our expectations." Recovering versions of the treatises in the language in which Archimedes wrote will give insight into "how Archimedes' brain worked," he adds.

Archimedes was born in 287 B.C., in Syracuse, on the island of Sicily, then a part of Greece. He made numerous discoveries in geometry, physics, and mechanics and he developed theorems that foreshadowed calculus. He was killed by a Roman soldier in 212 B.C.

Archimedes recorded his works on the paper of the time--papyrus scrolls. None of those scrolls survived, but over the centuries, his scholarship was copied and recopied. In Constantinople, sometime in the 10th century, seven of his treatises were copied onto parchment using iron gall ink, an acidic mixture made from iron and crushed growths found on oak trees.

High-tech tools reveal the perpendicular underlayer of Archimedes' treatise.
Photo courtesy of JHU by permission of owner
Two hundred years later, when parchment was in short supply, scribes, perhaps unaware of the book's scholarly significance, scraped off the original text, cut the pages in half, turned them 90 degrees, and used them to record prayers for baptisms and other ceremonies.

Centuries passed. The palimpsest changed hands, survived fire and blight. Finally, in 1906, University of Copenhagen philologist Johan Ludvig Heiberg rediscovered the book, and transcribed what he could of the treatises using a magnifying glass.

Flash forward to 1998. An anonymous owner purchased the palimpsest at auction for $2 million, and deposited it at the Walters. Christens-Barry went to see the palimpsest when it was put on display, and immediately became interested in imaging its foggy underlayer.

Christens-Barry has used imaging to study a wide range of materials, from the moon and planets to ancient Egyptian papyrus scrolls. To study the palimpsest, he chose three techniques:

Multispectral imaging: Involves shining light on a manuscript page and detecting the reflected wavelengths with sophisticated digital cameras. When used with polarized light techniques, multispectral imaging reveals details about a material's texture. Tannic acid in the iron gall ink carved out microscopic pits, explains Christens-Barry. These pits reflect polarized light in a characteristic fashion.

Hyperspectral fluorescence imaging: Shining ultraviolet light on the parchment causes the material to "glow" or fluoresce, accentuating regions where the ink reacted chemically with the parchment.

Confocal microscopy: Uses a narrow beam of laser light to probe the depth of each page of parchment a sublayer at a time, as though each sheet has been sliced into ever finer sheets, each a few microns in depth. This enables researchers to distinguish the 12th-century text from the older 10th-century text.

Christens-Barry completed imaging of the first five leaves of the palimpsest this past summer. He collaborated with conservation scientist Johanna Bernstein, PhD, a lecturer in Materials Science. Among other discoveries, the researchers found that different imaging techniques perform better at different tasks. For example, hyperspectral fluorescence imaging appears to be the tool of choice for telling apart specks of mold from traces of ink, marks that are often indistinguishable to the naked eye. The scientists also discovered a special use for confocal microscopy. Several pages of the palimpsest are covered by illustrations of saints painted by forgers in the 20th century in an attempt to increase the book's value. The confocal microscope can peer under to clarify much of the text and diagrams underneath, says Christens-Barry.

With 169 pages left to analyze, says Noel, "there is a great deal more to get out of this manuscript. The best is yet to come." --MH


Photos courtesy APL
The end is NEAR

The honeymoon period is over.

In mid-February, NEAR Shoemaker, the first spacecraft to rendezvous with an asteroid, is finishing its year-long orbit of 433 Eros, the largest of the near-Earth asteroids. In its 2-billion- mile journey, NEAR has given scientists an historic glimpse of the ancient 21-mile-long space rock through 150,000 images and X-ray/gamma-ray spectrometer readings from ranges closer than three miles.

Among the primary findings: Eros 433 appears to be a fractured chip from a larger body dating back an estimated 4.5 billion years; linked to some of the most primitive meteorites in the solar system, the ordinary chondrites. Eros is cracked but solid, not the collection of rubble of which some asteroids are made. And high-resolution images show a grooved and ridged surface that has been beaten up over the ages--scientists have counted more than 100,000 craters wider than 50 feet and about 1 million house-sized or bigger boulders. Some of the main features, including the larger craters, have been tentatively named for famous lovers from history or fiction, including Lolita, Orpheus, and Don Juan.

NEAR Shoemaker locked into orbit with 433 Eros to much fanfare last Valentine's Day, after a four-year journey. The craft was the first launch in NASA's Discovery Program of low-cost planetary missions, with a price tag of $224 million. Hopkins's Applied Physics Laboratory designed and built the spacecraft, and managed the NEAR mission, short for Near Earth Asteroid Rendezvous; NASA later renamed the craft in honor of the late geologist Eugene Shoemaker.

On February 12, the final day of the mission, the car-sized craft is set to gather images from just 1,640 feet above the surface, before its telescope goes out of focus and it crash lands. Piles of data will continue to be analyzed after the landing as scientists work to understand the evolution of asteroids and the solar system itself. For mission details and images, visit APL's website: --JCS

Limacons and spirals on the move

Calculus is, essentially, a form of mathematical analysis concerned with rates of change. Were it applied to analyze the teaching of calculus, it would show a precipitous increase in the rate of change during the last 10 years.

"There's sort of an industry in calculus reform," says James Martino, director of undergraduate studies in mathematics at Hopkins, where calculus is a rite of passage for hundreds of students each year. For a decade, educators have been experimenting with changes in the traditional pedagogy to make the discipline less abstract, more focused on "real-world" application. And for the last two years the Hopkins math department has been experimenting with the Internet to revamp how it teaches the subject.

Illustration by James Yang
By using a Web-based graphing calculator, for example, Martino and his colleagues can now help students to develop the visual sense that's essential for working with calculus. Demonstrating the technology, math professor Joel Spruck brings up a Cartesian grapher on his computer screen, and inputs a function: He hits "return" and the grapher draws on the screen a parabolic curve that sweeps up the graph, curves down, then bends back up. A student using this and other graphers can input various functions and observe how the shapes change, producing circles, roses, lemniscapes, spirals, limacons--the whole calculus menagerie.

Spruck says, "With this, they understand immediately because of the picture." Adds Martino, "There are some things, if you can't visualize it, you can't even begin to set up the calculation. There's probably a dozen times a year when I'm drawing something on the blackboard and I wish I could make it move." With a computer and the Web, the drawing can move. "I tell students that I don't want to turn them into $50 calculators. We already have those. The emphasis for me is in developing their intuition. And a lot of that is graphical."

Hopkins professors have also found advantages to posting homework problems on the Web. Students immediately learn if they've solved the problem, instead of having to wait for the next class. Plus, they can log on and do Web-based homework from anywhere, anytime- -no need to visit the computer lab.

Spruck and Martino are still refining the tools for use in the Hopkins curriculum, but they're convinced the Internet is an ideal tool. Says Spruck, "There is no learning curve. They just sit down and work with it. Everything important to the course is on my Web site. Students are perfectly comfortable with that." --DK

A watery view of bone development

Meet Captain Hook, Chihuaha, Squiggle, and Mercedes. They are zebra fish mutants residing in a new research lab at Hopkins's School of Medicine, representing just a few of the genetic varieties that biologist Shannon Fisher is using to study bone development.

Fisher began setting up her lab last March. While a few other Hopkins researchers use zebra fish, her facility is by far the largest. When she completes filling her 530 tanks, they will hold 20,000 of the minnow-sized fish with the signature black stripe down their sides.

Joining the ranks of the fruit fly and mouse, the zebra fish, a freshwater native of Asia, is quickly becoming a favorite organism for developmental biologists. "You can see the brain develop, the eyes, the heart beating, the blood circulating," says Fisher. "You can even see them feed." There are also practical advantages: "One female can produce several hundred eggs each week, and they develop externally." Fisher has calculated that it costs only 3 cents per day to maintain a zebra fish, compared to a mouse's 20 to 25 cents per diem.

Fisher (yes, she has heard many jokes about her eponymous career choice, thank you) studies the genes that control skeletal development. She looks for fish that have abnormal skeletons, then maps the genes responsible for the abnormality. A label on each tank identifies the mutation.

For example, Chihuaha is short, with a broad forehead and small jaw; it appears to be a model for osteogenesis imperfecta, or brittle bone disease. Studying its early bone development could help illuminate the human condition. Squiggle is shaped like a stretched-out Z. Captain Hook's tail curls over. Mercedes' back fin looks like the Mercedes-Benz symbol. And then there's a tank labeled "Mystery Fish." They were lost from one of the tanks but it's not clear which one, says Fisher. "I didn't want to throw them away." --MH