Category: Lectures

Workshop Draws 60 of World’s Leading Materials Scientists

October 3rd, 2013 in Events, Faculty, Lectures, News-CE, News-EP, News-ISS, Research, Research-CE, Research-EP, Research-ISS

Organizing Committee (left to right): David Campbell, Chair (BU), Gabi Kotliar (Rutgers University), Karen Hallberg (Centro Atomico Bariloche), Hideo Hosono (Tokyo Institute of Technology), Meigan Aronson (SUNY Stonybrook), Andrei Ruckenstein (BU), and David Bishop (BU). Not pictured: Francisco de la Cruz (Centro Atomico Bariloche)

The conference organizing committee included: (left to right) Prof. David Campbell (Physics), chair; Gabi Kotliar (Rutgers University); Karen Hallberg (Centro Atomico Bariloche); Hideo Hosono (Tokyo Institute of Technology); Meigan Aronson (SUNY Stonybrook); Prof. Andrei Ruckenstein (Physics), and Prof. David Bishop (ECE), head of the MSE Division. Francisco de la Cruz (Centro Atomico Bariloche) was also a member of the committee.

A conference hosted by the Division of Materials Science & Engineering on September 27-29 brought 60 of the world’s leading materials scientists to campus to discuss the future of the rapidly emerging field of digital design of materials.

“Digital Design of Materials: The Way Forward for Materials Science?” included presentations and discussions on solid state chemistry in materials design and discovery, the search for materials such as superconductors, recent theoretical work underlying digital materials design, specific materials design techniques, and novel materials and their potential impact. Presentations focused on how advanced materials can be designed in silico, or via computer simulation.

ICAM-2-400x300 Prof. David Campbell (Physics), the former ENG dean and chair of the conference organizing committee, said, “We were delighted that all the speakers took very seriously the need to reach out across the different disciplines, presenting the key ideas in their fields in ways that led to robust discussions and interactions. We are very hopeful that this meeting will help nucleate an on-going dialogue on the prospects of designing materials in silico.”

Researchers are moving beyond the explanation of complex materials’ properties and toward the prediction of how new materials will behave, a much harder task. Key to that will be harnessing the power of advanced computational capabilities to develop novel devices and technologies in silico. While computers have not yet reached the level required for this work, conference participants discussed the extent to which new materials’ properties can be predicted using existing advanced computational tools combined with researchers’ experience.

Conference sponsors included Boston University, the Division of Materials Science & Engineering, the Institute for Complex Adaptive Matter and the National Science Foundation.

-Cheryl R. Stewart

Densmore Talks Programming Life on DISCOVER Panel

June 4th, 2013 in Events, Faculty, Lectures, News-CE, Recognition, Research, Research-CE, Video

Assistant Professor Douglas Densmore (ECE) speaks during the Catalyzing Biological Engineering panel. Photo by Christine Fu.

Assistant Professor Douglas Densmore (ECE) speaks during the Catalyzing Biological Engineering panel. Photo by Christine Fu.

“What is synthetic biology and what can it do?” asked Corey Powell, the editor-at-large of DISCOVER magazine, at a recent conference on the topic. “You’re lucky that you have the world’s leaders in that field right here giving you authoritative answers.”

One of those leaders was Boston University Assistant Professor Douglas Densmore (ECE) who participated in the event, Programming Life: The Revolutionary Potential of Synthetic Biology, on March 25. The conference was sponsored by DISCOVER magazine and SynBERC.

“To me, synthetic biology really is to be able to engineer things using abstraction, modularity and rules,” said Densmore. “If we can compose systems rationally, then ultimately people like myself can get in and build tools and techniques and algorithms to do that.”

Currently, Densmore is working to make the design of synthetic biological systems more mechanized through electronic design automation. CLOTHO, a unified tool set he and his team have designed, encapsulates this research.

His interest in synthetic biology began, in part, when he realized that DNA assembly was not a very efficient or organized practice.

“As a computer engineer, I said there’s a lot of things wrong with this fundamentally,” said Densmore.

At the conference, Densmore spoke on the Catalyzing Biological Engineering panel. The only computer engineer in the discussion, Densmore served as an example of how non-linear the field of biology really is.

Much of the day-long event aimed to show that synthetic biology could be used to make a better world – improving everything from human health to food supplies. To make these changes though, minds from many academic disciplines will need to work together.

Densmore is playing his part by getting students excited about the field, which can be a challenge since researching synthetic biology isn’t as much of an established career path as opposed to, say, working for Google.

“You really have a chance to be a pioneer in this field,” said Densmore. “The kinds of things that we establish now I believe will set the stage for the future.”

Watch the complete video of the panel discussion at DISCOVER.

-Rachel Harrington (rachelah@bu.edu)

Building a Better Network

May 8th, 2013 in Events, Graduate Student Opportunities, Lectures, News-CE, Research, Research-CE, Undergraduate Student Opportunities

Keren Bergman

Professor Keren Bergman visited Boston University's Department of Electrical & Computer Engineering as part of the Distinguished Lecture Series in April.

Just fifteen years ago, internet browsing usually involved leaving the room to kill time as a dial-up modem slowly connected you to the world wide web. The process might have been painful but we didn’t know any better.

Fast forward to 2013 and these past connection speeds seem archaic. Still, that doesn’t stop some researchers from asking the question – can we be faster?

Professor Keren Bergman of Columbia University is one of those researchers asking that and she believes the answer is yes.

“It’s all about communication,” she said. “How do you get all of this data to talk to each other in the most effective way?”

In April, Bergman visited Boston University’s Department of Electrical & Computer Engineering as part of the Distinguished Lecture Series. She offered insight into one of her areas of expertise, optically enabled data.

During the lecture, Bergman discussed how recent advances in chip-scale silicon photonic technologies have the potential for developing optical interconnection networks that provide communications that are highly efficient and improve upon computing performance-per-Watt.

“With optical interconnects, it’s possible to build a better system that you couldn’t with electronics,” said Bergman.

As part of her work with the Lightwave Research Laboratory, some of Bergman’s other research centers around fiber optics through which data can be sent in the form of light waves.

“Compared to electronic routers, you can send a tremendous amount of data using photonic interconnects for computing platforms,” she said.

At this time, the fiber optic network isn’t configured in a way that’s particularly efficient, but according to Bergman, it has the potential to carry data faster than traditional copper wires.

In addition to teaching at Columbia, Bergman is an IEEE and Optical Society of America Fellow and serves as co-Editor-in-Chief of the IEEE/OSA Journal of Optical Communications and Networking.

Bergman’s talk was the third in the three-part Spring 2013 Distinguished Lecture Series. The lectures will resume again in Fall 2013.

-Rachel Harrington (rachelah@bu.edu)

(Don’t) Dry Your Tears

March 26th, 2013 in Events, Lectures, News-ISS, Research, Research-ISS

Dr. Kim Boyer of Rensselaer Polytechnic Institute, a longtime researcher of computer vision and medical image analysis, visited Boston University’s Department of Electrical & Computer Engineering as part of the Distinguished Lecture Series on March 20.

Dr. Kim Boyer of Rensselaer Polytechnic Institute, a longtime researcher of computer vision and medical image analysis, visited Boston University’s Department of Electrical & Computer Engineering as part of the Distinguished Lecture Series on March 20.

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 (rachelah@bu.edu)

Listen to Dr. Kim Boyer explain his research on WAMC Northeast Public Radio.

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.

A BU Center to Promote Cleaner Cities?

March 15th, 2013 in Events, Faculty, Graduate Programs, Lectures, News-ISS, Research, Research-ISS, Undergraduate Programs

Just one idea proposed at Smarter Cities conference

Christos Cassandras talked about technology being able to assist with the hassle of finding a parking space. (Photos by Kalman Zabarsky)

Christos Cassandras talked about technology being able to assist with the hassle of finding a parking space. (Photos by Kalman Zabarsky)

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.

Hutyra supports the idea of a BU center on urban science.

Hutyra supports the idea of a BU center on urban science.

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

Solar Energy for the Masses

October 30th, 2012 in Events, Faculty, Graduate Programs, Lectures, News-EP, Research, Research-EP, Students, Undergraduate Programs

Dr. Supratik Guha, director of the Physical Sciences Department at the IBM Thomas J. Watson Research Center, spoke at Boston University in October.

Dr. Supratik Guha, director of the Physical Sciences Department at the IBM Thomas J. Watson Research Center, spoke at Boston University in October.

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 (rachelah@bu.edu)


Envisioning a Bright Future for MBE Research

April 5th, 2012 in Events, Faculty, Lectures, Research, Research-EP

Charles Tu

Charles Tu speaks about developing dilute nitride crystals at the Department of Electrical & Computer Engineering Distinguished Lecture Series.

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 (rachelah@bu.edu)

Trapping Light the Topic of Recent Distinguished Lecture

December 6th, 2011 in Events, Lectures, News-CE, News-EP, News-ISS

Professor Diederik S. Wiersma, the director of the European Laboratory for Non-Linear Spectroscopy (LENS) at the University of Florence, spoke at Boston University as part of the ECE Distinguished Lecture Series.

Professor Diederik S. Wiersma, the director of the European Laboratory for Non-Linear Spectroscopy (LENS) at the University of Florence, spoke at Boston University as part of the ECE Distinguished Lecture Series.

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 (rachelah@bu.edu)

Latest Distinguished Lecture Discusses Improving Wireless Networks

October 18th, 2011 in Events, Lectures

Professor Behnaam Aazhang, who teaches at both Rice University and the University of Oulu in Finland, spoke last week as part of the ECE Department's Distinguished Lecture Series.

Professor Behnaam Aazhang, who teaches at both Rice University and the University of Oulu in Finland, spoke last week as part of the ECE Department's Distinguished Lecture Series.

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 (rachelah@bu.edu)

ECE Distinguished Lecture Series Opens With Professor Alok Choudhary

September 19th, 2011 in Events, Lectures, News-CE, News-EP, News-ISS

Choudhary

Professor Alok N. Choudhary of Northwestern University kicked off the Fall 2011 ECE Distinguished Lecture Series last week.

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 (rachelah@bu.edu)