Long-time contact lens wearers often complain of dry eyes. Sometimes the pupils can feel scratchy and turn red, and in extreme cases, prescription eye drops are needed to relieve the pain.
Dr. Kim Boyer of Rensselaer Polytechnic Institute, a longtime researcher of computer vision and medical image analysis, hopes to develop better treatments and therapies for dry eye syndrome.
The dryness occurs, he said, when a person isn’t properly producing tears, which help relubricate the eyes. The question is – when this is happening, where are the tears going?
“The answer to this is not well-understood,” said Boyer.
On March 20, Boyer visited Boston University’s Department of Electrical & Computer Engineering as part of the Distinguished Lecture Series. He spoke about his joint research with Ph.D. student, Dijia Wu, concerning building an accurate fluid dynamics model of tears that could eventually result in both improved treatments and more effective products for treating dry eyes.
To collect their data, Boyer and Wu use a narrowband interferometer to capture video of tear movement.
“We shoot a narrow band of light into the eye which reflects on the surface of the tear or lens,” said Boyer.
From there, Boyer and Wu identify dry regions by watching the rings around the eyes.
From this information, the researchers have developed a new method for reconstructing the tear film surface over the wet regions. The tear film is important as it serves several purposes in one’s eye: it keeps it moist, creates a smooth surface for light to pass through, and provides protection from injury and infection. Boyer’s and Wu’s method to reconstruct it has already showed signs of effectiveness with synthetic and prelens tear film.
“We hope to continue working with our colleagues in optometry and fluid dynamics to develop a deeper understanding of tear film behavior,” said Boyer.
Boyer, the head of the Department of Electrical, Computer & Systems Engineering at RPI, has published over 100 papers and five books. He is also a former contacts wearer.
-Rachel Harrington (email@example.com)
Boyer’s talk was the second in the three-part Spring 2013 Distinguished Lecture Series. The next talk features Professor Keren Bergman, chair of Electrical Engineering at Columbia University. She will speak on the topic, “Scalable Computing Systems With Optically Enabled Data Movement.” Hear her on Wednesday, April 10, 2013, at 4 p.m. in PHO211.
Just one idea proposed at Smarter Cities conference
As both an engineer and a motorist, Christos Cassandras (ECE, SE) feels the pain of drivers on Commonwealth Avenue. Although he usually leaves work after the evening rush has waned, he invariably hits a red light at the BU Bridge, even when there’s no traffic coming on the cross street. After that, it’s one red light after another along the avenue with its synchronized traffic lights—“just to make my life as miserable as possible.”
Wouldn’t it be nice if communicating “smart” lights could sense when there’s no oncoming traffic and wave you through, the College of Engineering professor mused to a packed house attending Wednesday’s Smarter Cities conference at the Photonics Center. That dream could be realized someday by the nascent technologies Boston and other cities are pioneering to collect, analyze, and act on data such as traffic counts, according to Cassandras and other speakers.
In fact, we already have a high-tech version of the old-fashioned parking garage. Cassandras said data shows motorists in major urban downtowns, including Boston’s, cruise an average of eight minutes in search of a parking space. BU has one garage linked to a “smart” parking system: motorists can check an app on their handheld devices to see if there’s an open space in the garage. (Reserving it, however, is one bug that still remains to be ironed out, Cassandras said.)
IBM bankrolled the conference as part of its Smarter Cities program, which supports data gathering to improve environmental, health, safety, and productivity initiatives in communities where company employees work and live. Lucy Hutyra, a College of Arts & Sciences assistant professor of earth and environment, is working with a grant from the IBM program to calculate better traffic counts in Boston and their related greenhouse gas emissions, which foster climate change.
Tag-teaming with Cassandras on his presentation to the assemblage of BU, IBM, and municipal leaders, Hutyra proposed creating a center or institute at the University to study and coordinate projects in environmental sustainability.
Boston has cut its greenhouse gas emissions to 7 percent below the 1990 levels, and Mayor Thomas Menino (Hon.’01) has targeted a reduction of 25 percent below that year’s levels over the next seven years. Statewide, Massachusetts hopes for a whopping 80 percent cut in emissions by 2050. The problem, Hutyra said in an interview, is that current emissions counts aren’t very good: they’re based on taking gas consumption and industrial activities and estimating average emissions resulting from each. Traffic counts are used occasionally as well, she said, although they aren’t conducted frequently enough to be of much value. She said that depending on who’s measuring, current emission estimates for Massachusetts can vary by as much as 40 percent.
“Nobody’s trying to cheat,” Hutyra said. It’s just that “we need better verification.” That could be achieved with laser spectroscopy technology that measures emission levels directly in the atmosphere; BU has such a sensor atop CAS measuring carbon dioxide, a major greenhouse gas. It’s part of a network of half a dozen sensors that BU and Harvard colleagues have established.
A center would enable government-corporate-academic partnerships, such as her Smarter Cities project, to “be more than one-offs—be something that is sustainable and something that can grow and evolve over time,” Hutyra said. She has discussed her idea for such a center with ENG Dean Kenneth Lutchen, another conference speaker, who expressed support in an interview.
“I think there’s a tremendous opportunity to create an integrated center or institute,” he said. “It would be a University-wide hub institute, which would have coalitions and partnerships with the private sector and government.” Budgeting such a center would require “a foundation or a company or a benefactor,” and “in order to make that work, you need one or more iconic, visionary faculty leaders to help coordinate it.
“The next step is to identify how the key stakeholders would like to integrate and work at a University hub institute or center,” Lutchen said, “and identify what should be the portion of it that the University has to ante up, both with some staff resources and faculty time, and what should be the contributions from external constituents such as companies, foundations, or perhaps government funding… I think we’re potentially a year or maybe two away from a major center.”
He noted that BU’s Sustainable Neighborhood Laboratory (SNL) already works with IBM, the city, and other businesses to make Boston “smarter.” For example, SNL and partners are working to collect and analyze data about energy use in Boston residential buildings and hotels to improve energy efficiency. One result: the Lenox Hotel recently installed energy-efficient windows, lighting, and insulation.
In another project, SNL is working with Roxbury’s Madison Park Development Corp., which operates more than 1,000 housing units for low-income Bostonians, to study energy use in those homes and how to make them more efficient.
-Rich Barlow, BU Today
As the need for renewable energy sources grows, solar energy has become a popular area of research. However, developing solar cell technology that can be used by the masses continues to be a challenge because of high prices and great performance demands.
“There are still some breakthroughs needed to bring down the cost and make the design more scalable,” said Dr. Supratik Guha, director of the Physical Sciences Department at the IBM Thomas J. Watson Research Center.
Guha, whose research centers around new semiconductors and oxides for logic and energy analytics, visited Boston University on October 3 as part of the Department of Electrical & Computer Engineering Distinguished Lecture Series. As part of his talk, he spoke about the challenges of designing better equipment to collect solar cells.
“The demand for solar energy isn’t growing as quickly as we would like in the US because the demand for new utility systems isn’t as high,” said Guha.
As part of his research, Guha is exploring one of the ways solar energy can be harnessed by studying photovoltaics, a method of creating electric power by turning solar radiation into electricity using semiconductors.
Globally, solar photovoltaics is the third most popular renewable energy source behind wind and water power, but until cheaper materials are used to design solar cell equipment, the technology is not likely to pass fossil fuels as a top source of energy.
Enter Guha whose research team is looking at fabricating solar cells with copper-zinc-tin-sulfide (CZTS). According to Guha, the material is non-toxic and has the potential to have higher efficiency rates.
“We want to get away from fancy and expensive techniques,” he said.
The initial results show room for improvement since voltages were poor, but Guha said that his team will make advancements.
He believes that the ultimate goal, set forth by the Department of Energy, is to design a module that costs less than 50 cents a unit with the rest of system costing no more than $1 per watt.
“We’ve made a lot of progress, but new material discovery is still needed in order to make solar cells a widely used energy source,” said Guha.
Guha’s talk was the first in the two-part Fall 2012 Distinguished Lecture Series. The next talk features Professor Keren Bergman, Chair of the Department of Electrical Engineering at Columbia University. She will speak on the topic, “Scalable Computing Systems With Optically Enabled Data Movement.” Hear her on Wednesday, November 7, 2012, at 4 p.m. in PHO 211.
-Rachel Harrington (firstname.lastname@example.org)
Charles Tu, an associate dean of UC San Diego’s Jacobs School of Engineering, is known for advancing the field of Molecular Beam Epitaxy (MBE), a method of depositing crystals atomic layer by atomic layer that is used to build devices like high-performance transistors, lasers, and solar cells.
He has already had many firsts in his work. Tu was the first to set up a gas-source MBE system in a university in the United States which allowed his research team to grow a wider variety of materials, such as arsenide and phosphides, than were previously possible. Today, he and his research team are growing dilute nitrides and are hoping they will be used toward improving solar power.
Tu had another first in his life last week when he delivered a lecture at Boston University as part of the Department of Electrical & Computer Engineering Distinguished Lecture Series. The series invites prominent engineers to the university to speak about their research, and this was the first time Tu had spoken at BU.
During the lecture, Tu talked about developing dilute nitride crystals in his lab – a process that can get quite hot.
“I tell my students that working in my lab takes 1% inspiration and 99% perspiration,” he joked.
Tu offered background information about the growing process and said that he was very hopeful that this material could be used to make solar cells more efficient.
The talk not only gave students a chance to meet the renowned professor; it also gave Tu a chance to reconnect with Professor Theodore Moustakas (ECE), who has also made a name for himself in the MBE field. Moustakas said that it had been a pleasure to welcome Tu to campus.
“Incidentally his work and mine overlap quite a bit,” Moustakas told the audience as he introduced Tu at last week’s lecture.
Tu and Moustakas share another thing in common, too. They both previously won the MBE Innovator Award, given by the North American Molecular Beam Epitaxy (NAMBE) Conference.
In addition to that prize, Tu was awarded the Engineering Educator of the Year Award from San Diego County and the Pan Wen-Yuan Outstanding Research Award in Taiwan. He has also co-authored more than 390 journal papers.
-Rachel Harrington (email@example.com)
In photonics, understanding how light transmits through structures and being able to control that flow is a top research priority. Breakthroughs in this area have the potential to improve how information is carried through light, create antennas that are more highly direct, and more.
Professor Diederik S. Wiersma, the director of the European Laboratory for Non-Linear Spectroscopy (LENS) at the University of Florence and research director at the National Institute of Optics, believes that if light were to follow Lévy flights, new doors could be opened in photonics.
“Light that follows a disordered path has the potential to create new possibilities for light sources and information transport,” he said.
On November 29, Wiersma spoke about his work at Boston University as part of the Fall 2011 Distinguished Lecture Series, which brings groundbreaking engineers to the university.
Additionally, Wiersma and his research team have looked at how Anderson localization – the absence of wave diffusion in a disordered medium – can be used to make light waves more concentrated.
“Using the Anderson method, we also have the potential to make solar cells more efficient,” he said.
Trapping light while keeping it useful and intact is the goal. According to Wiersma, catching light waves in 2-D can already be done pretty easily, but the challenge comes in figuring our how to trap light in a 3-D photonic structure. He and his research group are working hard to find a way to minimize reflection and keep the photons moving within semiconductors.
This was the last talk in the Fall 2011 Distinguished Lecture Series. Please see our Distinguished Lectures page for a list of Spring 2012 talks.
-Rachel Harrington (firstname.lastname@example.org)
As use of Wi-Fi and cell phones increased over the last decade, networks have operated less and less efficiently. This is due, in part, to the fact that current wireless architectures rely on interference avoidance to eliminate simultaneous transmissions and avoid collisions at the receivers.
Researchers like Professor Behnaam Aazhang, who teaches at both Rice University and the University of Oulu in Finland, believe that there is an alternative solution to this problem.
“The current system is not optimal,” Aazhang told a Boston University audience last week. “We’re looking at how you can isolate channels in order to divide resources and avoid interference. Potentially, the effective bandwidth could be tripled by separating channels.”
Aazhang was the second speaker of the Department of Electrical & Computer Engineering’s Fall 2011 Distinguished Lecture Series, which brings engineering innovators to campus.
During his talk, he suggested that network capacity could be increased if neighboring nodes combined their resources and worked together on signal transmissions.
“Cooperation is key to this method,” Aazhang said. “If we can retransfer information, reliability and efficiency can be improved.”
Aazhang and his research team are currently exploring location information and network awareness in hopes of increasing both spectral and power efficiencies of the network.
Aazhang’s talk was the second in the three-part Fall 2011 Distinguished Lecture Series. The next talk features Professor Diederik S. Wiersma of the University of Florence who will speak on the topic, “Trapping the Light Fantastic.” Hear him on November 29 at 4 p.m. in PHO 906.
-Rachel Harrington (email@example.com)
The amount of information yielded by modern day technologies is accumulating at an astonishing pace. Commercial services using satellites, imaging devices, and sensor networks, to name a few, produce vast amounts of data. Social media and its communities on Facebook, Twitter and other sites are not far behind.
With so much information out there, researchers like Professor Alok N. Choudhary are hoping to take a look at all of the accruing data and see what can be discovered from it.
“When you have a huge amount of data, how can you use it to make the world better?” he asked a Boston University crowd on Wednesday.
Choudhary, who teaches in the Electrical Engineering and Computer Science Department at Northwestern University, visited Boston University’s Electrical and Computer Engineering Department last week. He was the first speaker of the Fall 2011 Distinguished Lecture Series, which brings groundbreaking engineers to the university.
He spoke about his research team’s work on data mining to faculty, students, staff, and other members of Boston’s engineering community.
Data mining, though a fairly new field of computer science, is allowing for the discovery of new patterns from immense data sets using artificial intelligence, statistics, and database management.
As an example, Choudhary and his research team recently looked at the tweets from the 2011 Egyptian revolution, an uprising that social media played a large role in.
One feature already enabled on Twitter is “Trending Topics,” which allows users to see the most popular words or phrases being used throughout the site at any given moment.
In the case of the Egyptian revolution, looking at tweets with the word “Egypt” would pull up a lot of posts about the revolution but might leave out messages that only included “Cairo” or “Mubarak,” the then-Egyptian president.
“Given a trending topic, one of the challenges is identifying similar trending topics on Twitter,” Choudhary said. “In data mining, defining these similarities or determining different kinds of relationships – theme, spatial, temporal – is important when looking at patterns.”
Another challenge of collecting information from Twitter is identifying what sources are the most significant or persuasive. A user might tweet frequently about a topic like Egypt, but the messages may be spam.
“If someone has lots of tweets but no one following, it’s probably spam,” said Choudhary. “Quantity doesn’t necessarily mean influential.”
On the other hand, Choudhary and his research team found that CNN and Al Jazeera offered messages that were frequently shared during the revolution. Egyptian origin journalist, Mona Eltahawy, had only a few hundred followers at the start of January when the uprising began, but her posts were among the most influential and also became among the most retweeted.
Time will only tell what other information data mining can uncover, but Choudhary and his team are off to a good start.
Choudhary’s talk was the first in the three-part Fall 2011 Distinguished Lecture Series. The next talk features Professor Behnaam Aazhang of Rice University who will speak on the topic, “Context Aware Wireless Networks: A Physical Layer Perspective.” Hear him on October 12, 2011, at 4 p.m. in PHO 211.
-Rachel Harrington (firstname.lastname@example.org)
The organizers of the 20th International Symposium on Mathematical Theory of Networks and Systems recently asked Tannenbaum to deliver a plenary lecture at their July 2012 conference in Melbourne, Australia.
“This is an honor because this is one of the major conferences on mathematical systems theory,” said Tannenbaum.
The interdisciplinary conference looks at mathematical structures and how they connect to the understanding of networks, systems and networked systems.
A previous attendee, Tannenbaum looks forward to returning and seeing the latest cutting-edge results from the leaders of the field.
At the Symposium, he plans to speak about optimal mass transport as applied to problems in information theory, signal processing and control.
Tannenbaum’s current research interests include systems and control; image processing; medical imaging; computer vision; and signal processing.
-Rachel Harrington (email@example.com)
The achievements of Professor Theodore Moustakas (ECE), associate head of the Division of Materials Science & Engineering, are legion. He is perhaps best known for pioneering the nucleation steps for the growth of gallium nitride on sapphire and other substrates, an essential process for the manufacture of blue LEDs, which are widely used in solid state lighting applications; and for developing highly-efficient, deep ultraviolet (UV) LEDs, which are expected to provide environmentally friendly water and air purification.
On March 3, Moustakas discussed the primary focus of his research—the fabrication of nitride semiconductors for high-performance visible and UV LEDs—in the 2011 College of Engineering Distinguished Scholar Lecture, “Nitride Semiconductors and their Applications to Solid State Lighting and Water/Air Purification.” Speaking at the Trustee Center Ballroom, he addressed students, faculty and researchers from throughout the Boston University academic community and other Boston-area research institutions.
A professor in the ECE Department for more than 20 years, Moustakas has had a significant impact on his field, through 25 patents, hundreds of invited talks and journal papers, eight co-edited books and 7,000 citations in research literature. Recently selected as the 2010 Molecular Beam Epitaxy (MBE) Innovator Award, he has been named a Fellow of the American Physical Society and Electrochemical Society.
“What an extraordinary volume of incredible and creative work by Ted,” said Dean Kenneth R. Lutchen, acknowledging not only Moustakas’ significant research achievements but also his leading role in propelling the ECE Department’s PhD program into the nation’s top-ranked programs, putting the MSE Division on the national map and helping establish BU as a national center of photonics research. “Ted is really an icon of excellence and impact, and incredible dedication to Boston University.”
Nitride Semiconductors and Their Applications
“I am humbled to come here and talk to you about solid state lighting,” said Moustakas. “I was born in a small village in Greece, and I would study my school books using a lantern that burned oil.”
Moustakas observed that nitride semiconductors such as indium, gallium and aluminum nitride cover the entire range of the electromagnetic spectrum, from the infrared to the deep UV; and exhibit high thermal conductivity, chemical resistance, radiation-hardness, and other properties that make them suitable for a wide range of applications.
These include existing devices and technologies such as photovoltaic solar cells, biological and chemical detectors, full-color displays, optical recording lasers, high-temperature and high-power electronics, visible and UV lasers—as well as emerging LED-based applications such as solid state lighting for general illumination and water, air and surface sterilization.
White-Light LEDs for General Illumination
Providing the same light for less than half the energy required by a compact fluorescent bulb and lasting up to 100,000 hours, a high-quality white-light LED would reduce U.S. energy costs by up to $20 billion and carbon dioxide emissions by 150 million tons annually, but today’s white-light LEDs are inadequate for use in general lighting applications, Moustakas noted.
To produce white light that you can read by, blue, green and red LEDs must be combined—and making green LEDs is very inefficient and costly. Moustakas’s group has made significant progress in resolving this “green gap” by developing semiconductor particles called quantum dots that exhibit unique properties.
“The Department of Energy projects that by 2020 LEDs will produce approximately 150-200 lumens per watt and replace all other light sources for general illumination,” said Moustakas.
UV LEDs for Water/Air Purification
Dividing the ultraviolet spectrum, which extends from 10 to 400 nanometers of radiation frequency, into four domains, Moustakas called special attention to LEDs that emit light in the UV-C range (200-290 nm).
“UV-C radiation can damage microorganisms’ DNA, and we can use this radiation for water, air and surface decontamination, for example, in hospitals,” said Moustakas. “This radiation can also be used to detect chemical and biological substances, which has both medical and security implications.”
Nucleic acids in DNA and RNA absorb UV radiation from the 240-290 nm range, with peak absorption at 266 nm, he explained. A UV light source at 266 nm would prevent a microorganism’s DNA and RNA from replicating, thereby killing it.
“Recently, the U.S. Environmental Protection Agency has recommended UV-radiation as the most sound technology to inactivate pathogenic microorganisms—instead of chlorination—in public water supplies,” said Moustakas, noting that approximately 2,000 UV drinking water treatment systems exist in Europe, and 1,000 in the U.S.
Current UV-LEDs are energy-inefficient, but Moustakas’s group has produced aluminum gallium nitride alloys that promise to significantly improve UV-LED performance.
Moustakas also described some of his research group’s many scientific contributions to the development of high-performance nitride semiconductors, including progress in growing nitride semiconductors using sophisticated methods such as an atom-by-atom assembly technique called molecular beam epitaxy.
Initiated in 2008, the annual Distinguished Scholar Lecture Series honors a senior faculty member engaged in outstanding, high-impact research at the College of Engineering. The previous three recipients are Professors Irving Bigio (ECE, BME), John Baillieul (ECE, ME) and Malvin Teich (ECE).
Not everyone is born with a singing voice that will win them a spot on Glee or American Idol, but what if you could improve the sound of a truly terrible vocalist?
That’s part of the idea behind the work of Professor Mark J. T. Smith, Dean of the Graduate School at Purdue University, and his colleagues.
He and his research team are working toward using signal processing not only to improve music but foreign language education as well. They have recently been developing automated software that can be used to correct pronunciation errors in Spanish.
“Our program identifies the error in pronunciation, makes the correction, and then plays it back for the speaker,” said Smith. Currently, the software can correct errors in cadence, intonations, pitch and accents.
Smith spoke at Boston University March 2 as part of the ECE Department’s Distinguished Lecture Series, which brings prominent engineers to the university. He discussed the topic, “Improved Models for Accent Detection and Voice Synthesis.”
When modifying and synthesizing speech, there are many components that go into reaching the desired outcome including pitch control and control over the time scale. Smith said that he and his team have been using the ABS-OLA synthesis model in their work because of the greater flexibility this algorithm allows.
Development is not yet complete on the software, but when tested on isolated words like “hierro” (iron) – complicated for some because of the rolling “rr” –impressive results were achieved.
In addition to working at Purdue, Smith is a fellow of the IEEE and has authored many papers in the areas of speech and image processing, filter banks, and wavelets. He is also an accomplished fencer, having been a member of the U.S. Olympic Team in 1980 and 1984.
-Rachel Harrington (firstname.lastname@example.org)