Markus Andrews

More stories

  • 113 Shares119 Views

    in Data Management & Statistics

    Researchers create a tool for accurately simulating complex systems

    Researchers often use simulations when designing new algorithms, since testing ideas in the real world can be both costly and risky. But since it’s impossible to capture every detail of a complex system in a simulation, they typically collect a small amount of real data that they replay while simulating the components they want to study.

    Known as trace-driven simulation (the small pieces of real data are called traces), this method sometimes results in biased outcomes. This means researchers might unknowingly choose an algorithm that is not the best one they evaluated, and which will perform worse on real data than the simulation predicted that it should.

    MIT researchers have developed a new method that eliminates this source of bias in trace-driven simulation. By enabling unbiased trace-driven simulations, the new technique could help researchers design better algorithms for a variety of applications, including improving video quality on the internet and increasing the performance of data processing systems.

    The researchers’ machine-learning algorithm draws on the principles of causality to learn how the data traces were affected by the behavior of the system. In this way, they can replay the correct, unbiased version of the trace during the simulation.

    When compared to a previously developed trace-driven simulator, the researchers’ simulation method correctly predicted which newly designed algorithm would be best for video streaming — meaning the one that led to less rebuffering and higher visual quality. Existing simulators that do not account for bias would have pointed researchers to a worse-performing algorithm.

    “Data are not the only thing that matter. The story behind how the data are generated and collected is also important. If you want to answer a counterfactual question, you need to know the underlying data generation story so you only intervene on those things that you really want to simulate,” says Arash Nasr-Esfahany, an electrical engineering and computer science (EECS) graduate student and co-lead author of a paper on this new technique.

    He is joined on the paper by co-lead authors and fellow EECS graduate students Abdullah Alomar and Pouya Hamadanian; recent graduate student Anish Agarwal PhD ’21; and senior authors Mohammad Alizadeh, an associate professor of electrical engineering and computer science; and Devavrat Shah, the Andrew and Erna Viterbi Professor in EECS and a member of the Institute for Data, Systems, and Society and of the Laboratory for Information and Decision Systems. The research was recently presented at the USENIX Symposium on Networked Systems Design and Implementation.

    Specious simulations

    The MIT researchers studied trace-driven simulation in the context of video streaming applications.

    In video streaming, an adaptive bitrate algorithm continually decides the video quality, or bitrate, to transfer to a device based on real-time data on the user’s bandwidth. To test how different adaptive bitrate algorithms impact network performance, researchers can collect real data from users during a video stream for a trace-driven simulation.

    They use these traces to simulate what would have happened to network performance had the platform used a different adaptive bitrate algorithm in the same underlying conditions.

    Researchers have traditionally assumed that trace data are exogenous, meaning they aren’t affected by factors that are changed during the simulation. They would assume that, during the period when they collected the network performance data, the choices the bitrate adaptation algorithm made did not affect those data.

    But this is often a false assumption that results in biases about the behavior of new algorithms, making the simulation invalid, Alizadeh explains.

    “We recognized, and others have recognized, that this way of doing simulation can induce errors. But I don’t think people necessarily knew how significant those errors could be,” he says.

    To develop a solution, Alizadeh and his collaborators framed the issue as a causal inference problem. To collect an unbiased trace, one must understand the different causes that affect the observed data. Some causes are intrinsic to a system, while others are affected by the actions being taken.

    In the video streaming example, network performance is affected by the choices the bitrate adaptation algorithm made — but it’s also affected by intrinsic elements, like network capacity.

    “Our task is to disentangle these two effects, to try to understand what aspects of the behavior we are seeing are intrinsic to the system and how much of what we are observing is based on the actions that were taken. If we can disentangle these two effects, then we can do unbiased simulations,” he says.

    Learning from data

    But researchers often cannot directly observe intrinsic properties. This is where the new tool, called CausalSim, comes in. The algorithm can learn the underlying characteristics of a system using only the trace data.

    CausalSim takes trace data that were collected through a randomized control trial, and estimates the underlying functions that produced those data. The model tells the researchers, under the exact same underlying conditions that a user experienced, how a new algorithm would change the outcome.

    Using a typical trace-driven simulator, bias might lead a researcher to select a worse-performing algorithm, even though the simulation indicates it should be better. CausalSim helps researchers select the best algorithm that was tested.

    The MIT researchers observed this in practice. When they used CausalSim to design an improved bitrate adaptation algorithm, it led them to select a new variant that had a stall rate that was nearly 1.4 times lower than a well-accepted competing algorithm, while achieving the same video quality. The stall rate is the amount of time a user spent rebuffering the video.

    By contrast, an expert-designed trace-driven simulator predicted the opposite. It indicated that this new variant should cause a stall rate that was nearly 1.3 times higher. The researchers tested the algorithm on real-world video streaming and confirmed that CausalSim was correct.

    “The gains we were getting in the new variant were very close to CausalSim’s prediction, while the expert simulator was way off. This is really exciting because this expert-designed simulator has been used in research for the past decade. If CausalSim can so clearly be better than this, who knows what we can do with it?” says Hamadanian.

    During a 10-month experiment, CausalSim consistently improved simulation accuracy, resulting in algorithms that made about half as many errors as those designed using baseline methods.

    In the future, the researchers want to apply CausalSim to situations where randomized control trial data are not available or where it is especially difficult to recover the causal dynamics of the system. They also want to explore how to design and monitor systems to make them more amenable to causal analysis. More

  • 100 Shares169 Views

    in Data Management & Statistics

    Researchers develop novel AI-based estimator for manufacturing medicine

    When medical companies manufacture the pills and tablets that treat any number of illnesses, aches, and pains, they need to isolate the active pharmaceutical ingredient from a suspension and dry it. The process requires a human operator to monitor an industrial dryer, agitate the material, and watch for the compound to take on the right qualities for compressing into medicine. The job depends heavily on the operator’s observations.   

    Methods for making that process less subjective and a lot more efficient are the subject of a recent Nature Communications paper authored by researchers at MIT and Takeda. The paper’s authors devise a way to use physics and machine learning to categorize the rough surfaces that characterize particles in a mixture. The technique, which uses a physics-enhanced autocorrelation-based estimator (PEACE), could change pharmaceutical manufacturing processes for pills and powders, increasing efficiency and accuracy and resulting in fewer failed batches of pharmaceutical products.  

    “Failed batches or failed steps in the pharmaceutical process are very serious,” says Allan Myerson, a professor of practice in the MIT Department of Chemical Engineering and one of the study’s authors. “Anything that improves the reliability of the pharmaceutical manufacturing, reduces time, and improves compliance is a big deal.”

    The team’s work is part of an ongoing collaboration between Takeda and MIT, launched in 2020. The MIT-Takeda Program aims to leverage the experience of both MIT and Takeda to solve problems at the intersection of medicine, artificial intelligence, and health care.

    In pharmaceutical manufacturing, determining whether a compound is adequately mixed and dried ordinarily requires stopping an industrial-sized dryer and taking samples off the manufacturing line for testing. Researchers at Takeda thought artificial intelligence could improve the task and reduce stoppages that slow down production. Originally the research team planned to use videos to train a computer model to replace a human operator. But determining which videos to use to train the model still proved too subjective. Instead, the MIT-Takeda team decided to illuminate particles with a laser during filtration and drying, and measure particle size distribution using physics and machine learning. 

    “We just shine a laser beam on top of this drying surface and observe,” says Qihang Zhang, a doctoral student in MIT’s Department of Electrical Engineering and Computer Science and the study’s first author. 

    Play video

    A physics-derived equation describes the interaction between the laser and the mixture, while machine learning characterizes the particle sizes. The process doesn’t require stopping and starting the process, which means the entire job is more secure and more efficient than standard operating procedure, according to George Barbastathis, professor of mechanical engineering at MIT and corresponding author of the study.

    The machine learning algorithm also does not require many datasets to learn its job, because the physics allows for speedy training of the neural network.

    “We utilize the physics to compensate for the lack of training data, so that we can train the neural network in an efficient way,” says Zhang. “Only a tiny amount of experimental data is enough to get a good result.”

    Today, the only inline processes used for particle measurements in the pharmaceutical industry are for slurry products, where crystals float in a liquid. There is no method for measuring particles within a powder during mixing. Powders can be made from slurries, but when a liquid is filtered and dried its composition changes, requiring new measurements. In addition to making the process quicker and more efficient, using the PEACE mechanism makes the job safer because it requires less handling of potentially highly potent materials, the authors say. 

    The ramifications for pharmaceutical manufacturing could be significant, allowing drug production to be more efficient, sustainable, and cost-effective, by reducing the number of experiments companies need to conduct when making products. Monitoring the characteristics of a drying mixture is an issue the industry has long struggled with, according to Charles Papageorgiou, the director of Takeda’s Process Chemistry Development group and one of the study’s authors. 

    “It is a problem that a lot of people are trying to solve, and there isn’t a good sensor out there,” says Papageorgiou. “This is a pretty big step change, I think, with respect to being able to monitor, in real time, particle size distribution.”

    Papageorgiou said that the mechanism could have applications in other industrial pharmaceutical operations. At some point, the laser technology may be able to train video imaging, allowing manufacturers to use a camera for analysis rather than laser measurements. The company is now working to assess the tool on different compounds in its lab. 

    The results come directly from collaboration between Takeda and three MIT departments: Mechanical Engineering, Chemical Engineering, and Electrical Engineering and Computer Science. Over the last three years, researchers at MIT and Takeda have worked together on 19 projects focused on applying machine learning and artificial intelligence to problems in the health-care and medical industry as part of the MIT-Takeda Program. 

    Often, it can take years for academic research to translate to industrial processes. But researchers are hopeful that direct collaboration could shorten that timeline. Takeda is a walking distance away from MIT’s campus, which allowed researchers to set up tests in the company’s lab, and real-time feedback from Takeda helped MIT researchers structure their research based on the company’s equipment and operations. 

    Combining the expertise and mission of both entities helps researchers ensure their experimental results will have real-world implications. The team has already filed for two patents and has plans to file for a third.   More

  • 88 Shares99 Views

    in Data Management & Statistics

    Study: Covid-19 has reduced diverse urban interactions

    The Covid-19 pandemic has reduced how often urban residents intersect with people from different income brackets, according to a new study led by MIT researchers.

    Examining the movement of people in four U.S. cities before and after the onset of the pandemic, the study found a 15 to 30 percent decrease in the number of visits residents were making to areas that are socioeconomically different than their own. In turn, this has reduced people’s opportunities to interact with others from varied social and economic spheres.

    “Income diversity of urban encounters decreased during the pandemic, and not just in the lockdown stages,” says Takahiro Yabe, a postdoc at the Media Lab and co-author of a newly published paper detailing the study’s results. “It decreased in the long term as well, after mobility patterns recovered.”

    Indeed, the study found a large immediate dropoff in urban movement in the spring of 2020, when new policies temporarily shuttered many types of institutions and businesses in the U.S. and much of the world due to the emergence of the deadly Covid-19 virus. But even after such restrictions were lifted and the overall amount of urban movement approached prepandemic levels, movement patterns within cities have narrowed; people now visit fewer places.

    “We see that changes like working from home, less exploration, more online shopping, all these behaviors add up,” says Esteban Moro, a research scientist at MIT’s Sociotechnical Systems Research Center (SSRC) and another of the paper’s co-authors. “Working from home is amazing and shopping online is great, but we are not seeing each other at the rates we were before.”

    The paper, “Behavioral changes during the Covid-19 pandemic decreased income diversity of urban encounters,” appears in Nature Communications. The co-authors are Yabe; Bernardo García Bulle Bueno, a doctoral candidate at MIT’s Institute for Data, Systems, and Society (IDSS); Xiaowen Dong, an associate professor at Oxford University; Alex Pentland, professor of media arts and sciences at MIT and the Toshiba Professor at the Media Lab; and Moro, who is also an associate professor at the University Carlos III of Madrid.

    A decline in exploration

    To conduct the study, the researchers examined anonymized cellphone data from 1 million users over a three-year period, starting in early 2019, with data focused on four U.S. cities: Boston, Dallas, Los Angeles, and Seattle. The researchers recorded visits to 433,000 specific “point of interest” locations in those cities, corroborated in part with records from Infogroup’s U.S. Business Database, an annual census of company information.  

    The researchers used U.S. Census Bureau data to categorize the socioeconomic status of the people in the study, placing everyone into one of four income quartiles, based on the average income of the census block (a small area) in which they live. The scholars made the same income-level assessment for every census block in the four cities, then recorded instances in which someone spent from 10 minutes to four hours in a census block other than their own, to see how often people visited areas in different income quartiles. 

    Ultimately, the researchers found that by late 2021, the amount of urban movement overall was returning to prepandemic levels, but the scope of places residents were visiting had become more restricted.

    Among other things, people made many fewer visits to museums, leisure venues, transport sites, and coffee shops. Visits to grocery stores remained fairly constant — but people tend not to leave their socioeconomic circles for grocery shopping.

    “Early in the pandemic, people reduced their mobility radius significantly,” Yabe says. “By late 2021, that decrease flattened out, and the average dwell time people spent at places other than work and home recovered to prepandemic levels. What’s different is that exploration substantially decreased, around 5 to 10 percent. We also see less visitation to fun places.” He adds: “Museums are the most diverse places you can find, parks — they took the biggest hit during the pandemic. Places that are [more] segregated, like grocery stores, did not.”

    Overall, Moro notes, “When we explore less, we go to places that are less diverse.”

    Different cities, same pattern

    Because the study encompassed four cities with different types of policies about reopening public sites and businesses during the pandemic, the researchers could also evaluate what impact public health policies had on urban movement. But even in these different settings, the same phenomenon emerged, with a narrower range of mobility occurring by late 2021.

    “Despite the substantial differences in how cities dealt with Covid-19, the decrease in diversity and the behavioral changes were surprisingly similar across the four cities,” Yabe observes.

    The researchers emphasize that these changes in urban movement can have long-term societal effects. Prior research has shown a significant association between a diversity of social connections and greater economic success for people in lower-income groups. And while some interactions between people in different income quartiles might be brief and transactional, the evidence suggests that, on aggregate, other more substantial connections have also been reduced. Additionally, the scholars note, the narrowing of experience can also weaken civic ties and valuable political connections.

    “It’s creating an urban fabric that is actually more brittle, in the sense that we are less exposed to other people,” Moro says. “We don’t get to know other people in the city, and that is very important for policies and public opinion. We need to convince people that new policies and laws would be fair. And the only way to do that is to know other people’s needs. If we don’t see them around the city, that will be impossible.”

    At the same time, Yabe adds, “I think there is a lot we can do from a policy standpoint to bring people back to places that used to be a lot more diverse.” The researchers are currently developing further studies related to cultural and public institutions, as well and transportation issues, to try to evaluate urban connectivity in additional detail.

    “The quantity of our mobility has recovered,” Yabe says. “The quality has really changed, and we’re more segregated as a result.” More

  • 50 Shares149 Views

    in Data Management & Statistics

    Driving toward data justice

    As a person with a mixed-race background who has lived in four different cities, Amelia Dogan describes her early life as “growing up in a lot of in-betweens.” Now an MIT senior, she continues to link different perspectives together, working at the intersection of urban planning, computer science, and social justice.

    Dogan was born in Canada but spent her high school years in Philadelphia, where she developed a strong affinity for the city.  

    “I love Philadelphia to death,” says Dogan. “It’s my favorite place in the world. The energy in the city is amazing — I’m so sad I wasn’t there for the Super Bowl this year — but it is a city with really big disparities. That drives me to do the research that I do and shapes the things that I care about.”

    Dogan is double-majoring in urban science and planning with computer science and in American studies. She decided on the former after participating in the pre-orientation program offered by the Department of Urban Studies and Planning, which provides an introduction to both the department and the city of Boston. She followed that up with a UROP research project with the West Philadelphia Landscape Project, putting together historical census data on housing and race to find patterns for use in community advocacy.

    After taking WGS.231 (Writing About Race), a course offered by the Program in Women’s and Gender Studies, her first year at MIT, Dogan realized there was a lot of crosstalk between urban planning, computer science, and the social sciences.

    “There’s a lot of critical social theory that I want to have background in to make me a better planner or a better computer scientist,” says Dogan. “There’s also a lot of issues around fairness and participation in computer science, and a lot of computer scientists are trying to reinvent the wheel when there’s already really good, critical social science research and theory behind this.”

    Data science and feminism

    Dogan’s first year at MIT was interrupted by the onset of the Covid-19 pandemic, but there was a silver lining. An influx of funding to keep students engaged while attending school virtually enabled her to join the Data + Feminism Lab to work on a case study examining three places in Philadelphia with historical names that were renamed after activist efforts.

    In her first year at MIT, Dogan worked several UROPs to hone her own skills and find the best research fit. Besides the West Philadelphia Land Project, she worked on two projects within the MIT Sloan School of Management. The first involved searching for connections between entrepreneurship and immigration among Fortune 500 founders. The second involved interviewing warehouse workers and writing a report on their quality of life.

    Dogan has now spent three years in the Data + Feminism Lab under Associate Professor Catherine D’Ignazio, where she is particularly interested in how technology can be used by marginalized communities to invert historical power imbalances. A key concept in the lab’s work is that of counterdata, which are produced by civil society groups or individuals in order to counter missing data or to challenge existing official data.

    Most recently, she completed a SuperUROP project investigating how femicide data activist organizations use social media. She analyzed 600 social media posts by organizations across the U.S. and Canada. The work built off the lab’s greater body of work with these groups, which Dogan has contributed to by annotating news articles for machine-learning models.

    “Catherine works a lot at the intersection of data issues and feminism. It just seemed like the right fit for me,” says Dogan. “She’s my academic advisor, she’s my research advisor, and is also a really good mentor.”

    Advocating for the student experience

    Outside of the classroom, Dogan is a strong advocate for improving the student experience, particularly when it intersects with identity. An executive board member of the Asian American Initiative (AAI), she also sits on the student advisory council for the Office of Minority Education.

    “Doing that institutional advocacy has been important to me, because it’s for things that I expected coming into college and had not come in prepared to fight for,” says Dogan. As a high schooler, she participated in programs run by the University of Pennsylvania’s Pan-Asian American Community House and was surprised to find that MIT did not have an equivalent organization.

    “Building community based upon identity is something that I’ve been really passionate about,” says Dogan. “For the past two years, I’ve been working with AAI on a list of recommendations for MIT. I’ve talked to alums from the ’90s who were a part of an Asian American caucus who were asking for the same things.”

    She also holds a leadership role with MIXED @ MIT, a student group focused on creating space for mixed-heritage students to explore and discuss their identities.

    Following graduation, Dogan plans to pursue a PhD in information science at the University of Washington. Her breadth of skills has given her a range of programs to choose from. No matter where she goes next, Dogan wants to pursue a career where she can continue to make a tangible impact.

    “I would love to be doing community-engaged research around data justice, using citizen science and counterdata for policy and social change,” she says. More

  • 150 Shares159 Views

    in Data Management & Statistics

    Martin Wainwright named director of the Institute for Data, Systems, and Society

    Martin Wainwright, the Cecil H. Green Professor in MIT’s departments of Electrical Engineering and Computer Science (EECS) and Mathematics, has been named the new director of the Institute for Data, Systems, and Society (IDSS), effective July 1.

    “Martin is a widely recognized leader in statistics and machine learning — both in research and in education. In taking on this leadership role in the college, Martin will work to build up the human and institutional behavior component of IDSS, while strengthening initiatives in both policy and statistics, and collaborations within the institute, across MIT, and beyond,” says Daniel Huttenlocher, dean of the MIT Schwarzman College of Computing and the Henry Ellis Warren Professor of Electrical Engineering and Computer Science. “I look forward to working with him and supporting his efforts in this next chapter for IDSS.”

    “Martin holds a strong belief in the value of theoretical, experimental, and computational approaches to research and in facilitating connections between them. He also places much importance in having practical, as well as academic, impact,” says Asu Ozdaglar, deputy dean of academics for the MIT Schwarzman College of Computing, department head of EECS, and the MathWorks Professor of Electrical Engineering and Computer Science. “As the new director of IDSS, he will undoubtedly bring these tenets to the role in advancing the mission of IDSS and helping to shape its future.”

    A principal investigator in the Laboratory for Information and Decision Systems and the Statistics and Data Science Center, Wainwright joined the MIT faculty in July 2022 from the University of California at Berkeley, where he held the Howard Friesen Chair with a joint appointment between the departments of Electrical Engineering and Computer Science and Statistics.

    Wainwright received his bachelor’s degree in mathematics from the University of Waterloo, Canada, and doctoral degree in electrical engineering and computer science from MIT. He has received a number of awards and recognition, including an Alfred P. Sloan Foundation Fellowship, and best paper awards from the IEEE Signal Processing Society, IEEE Communications Society, and IEEE Information Theory and Communication Societies. He has also been honored with the Medallion Lectureship and Award from the Institute of Mathematical Statistics, and the COPSS Presidents’ Award from the Joint Statistical Societies. He was a section lecturer with the International Congress of Mathematicians in 2014 and received the Blackwell Award from the Institute of Mathematical Statistics in 2017.

    He is the author of “High-dimensional Statistics: A Non-Asymptotic Viewpoint” (Cambridge University Press, 2019), and is coauthor on several books, including on graphical models and on sparse statistical modeling.

    Wainwright succeeds Munther Dahleh, the William A. Coolidge Professor in EECS, who has helmed IDSS since its founding in 2015.

    “I am grateful to Munther and thank him for his leadership of IDSS. As the founding director, he has led the creation of a remarkable new part of MIT,” says Huttenlocher. More

  • 150 Shares109 Views

    in Data Management & Statistics

    Learner in Afghanistan reaches beyond barriers to pursue career in data science

    Tahmina S. was a junior studying computer engineering at a top university in Afghanistan when a new government policy banned women from pursuing education. In August 2021, the Taliban prohibited girls from attending school beyond the sixth grade. While women were initially allowed to continue to attend universities, by October 2021, an order from the Ministry of Higher Education declared that all women in Afghanistan were suspended from attending public and private centers of higher education.

    Determined to continue her studies and pursue her ambitions, Tahmina found the MIT Refugee Action Hub (ReACT) and was accepted to its Certificate in Computer Science and Data Science program in 2022.

    “ReACT helped me realize that I can do big things and be a part of big things,” she says.

    MIT ReACT provides education and professional opportunities to learners from refugee and forcibly displaced communities worldwide. ReACT’s core pillars include academic development, human skills development, employment pathways, and network building. Since 2017, ReACT has offered its Certificate in Computer and Data Science (CDS) program free-of-cost to learners wherever they live. In 2022, ReACT welcomed its largest and most diverse cohort to date — 136 learners from 29 countries — including 25 learners from Afghanistan, more than half of whom are women.

    Tahmina was able to select her classes in the program, and especially valued learning Python — which has led to her studying other programming languages and gaining more skills in data science. She’s continuing to take online courses in hopes of completing her undergraduate degree, and someday pursuing a masters degree in computer science and becoming a data scientist.

    “It’s an important and fun career. I really love data,” she says. “If this is my only time for this experience, I will bring to the table what I have, and do my best.”

    In addition to the education ban, Tahmina also faced the challenge of accessing an internet connection, which is expensive where she lives. But she regularly studies between 12 and 14 hours a day to achieve her dreams.

    The ReACT program offers a blend of asynchronous and synchronous learning. Learners complete a curated series of online, rigorous MIT coursework through MITx with the support of teaching assistants and collaborators, and also participate in a series of interactive online workshops in interpersonal skills that are critical to success in education and careers.

    ReACT learners engage with MIT’s global network of experts including MIT staff, faculty, and alumni — as well as collaborators across technology, humanitarian, and government sectors.

    “I loved that experience a lot, it was a huge achievement. I’m grateful ReACT gave me a chance to be a part of that team of amazing people. I’m amazed I completed that program, because it was really challenging.”

    Theory into practice

    Tahmina was one of 10 students from the ReACT cohort accepted to the highly competitive MIT Innovation Leadership Bootcamp program. She worked on a team of five people who initiated a business proposal and took the project through each phase of the development process. Her team’s project was creating an app for finance management for users aged 23-51 — including all the graphic elements and a final presentation. One valuable aspect of the boot camp, Tahmina says, was presenting their project to real investors who then provided business insights and actionable feedback.

    As part of this ReACT cohort, Tahmina also participated in the Global Apprenticeship Program (GAP) pilot, an initiative led by Talanta and with the participation of MIT Open Learning as curriculum provider. The GAP initiative focuses on improving diverse emerging talent job preparedness and exploring how companies can successfully recruit, onboard, and retain this talent through remote, paid internships. Through the GAP pilot, Tahmina received training in professional skills, resume and interview preparation, and was matched with a financial sector firm for a four-month remote internship in data science.

    To prepare Tahmina and other learners for these professional experiences, ReACT trains its cohorts to work with people who have diverse backgrounds, experiences, and challenges. The nonprofit Na’amal offered workshops covering areas such as problem-solving, innovation and ideation, goal-setting, communication, teamwork, and infrastructure and info security. Tahmina was able to access English classes and learn valuable career skills, such as writing a resume.“This was an amazing part for me. There’s a huge difference going from theoretical to practical,” she says. “Not only do you have to have the theoretical experience, you have to have soft skills. You have to communicate everything you learn to other people, because other people in the business might not have that knowledge, so you have to tell the story in a way that they can understand.”

    ReACT wanted the women in the program to be mentored by women who were not only leaders in the tech field, but working in the same geographic region as learners. At the start of the internship, Na’amal connected Tahmina with a mentor, Maha Gad, who is head of talent development at Talabat and lives in Dubai. Tahmina met with Gad at the beginning and end of each month, giving her the opportunity to ask expansive questions. Tahmina says Gad encouraged her to research and plan first, and then worked with her to explore new tools, like Trello.

    Wanting to put her skills to use locally, Tahmina volunteered at the nonprofit Rumie, a community for Afghan women and girls, working as a learning designer, translator, team leader, and social media manager. She currently volunteers at Correspondents of the World as a story ambassador, helping Afghan people share stories, community, and culture — especially telling the stories of Afghan women and the changes they’ve made in the world.

    “It’s been the most beautiful journey of my life that I will never forget,” says Tahmina. “I found ReACT at a time when I had nothing, and I found the most valuable thing.” More

  • 100 Shares199 Views

    in Data Management & Statistics

    Drones navigate unseen environments with liquid neural networks

    In the vast, expansive skies where birds once ruled supreme, a new crop of aviators is taking flight. These pioneers of the air are not living creatures, but rather a product of deliberate innovation: drones. But these aren’t your typical flying bots, humming around like mechanical bees. Rather, they’re avian-inspired marvels that soar through the sky, guided by liquid neural networks to navigate ever-changing and unseen environments with precision and ease.

    Inspired by the adaptable nature of organic brains, researchers from MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) have introduced a method for robust flight navigation agents to master vision-based fly-to-target tasks in intricate, unfamiliar environments. The liquid neural networks, which can continuously adapt to new data inputs, showed prowess in making reliable decisions in unknown domains like forests, urban landscapes, and environments with added noise, rotation, and occlusion. These adaptable models, which outperformed many state-of-the-art counterparts in navigation tasks, could enable potential real-world drone applications like search and rescue, delivery, and wildlife monitoring.

    The researchers’ recent study, published today in Science Robotics, details how this new breed of agents can adapt to significant distribution shifts, a long-standing challenge in the field. The team’s new class of machine-learning algorithms, however, captures the causal structure of tasks from high-dimensional, unstructured data, such as pixel inputs from a drone-mounted camera. These networks can then extract crucial aspects of a task (i.e., understand the task at hand) and ignore irrelevant features, allowing acquired navigation skills to transfer targets seamlessly to new environments.

    Play video

    Drones navigate unseen environments with liquid neural networks.

    “We are thrilled by the immense potential of our learning-based control approach for robots, as it lays the groundwork for solving problems that arise when training in one environment and deploying in a completely distinct environment without additional training,” says Daniela Rus, CSAIL director and the Andrew (1956) and Erna Viterbi Professor of Electrical Engineering and Computer Science at MIT. “Our experiments demonstrate that we can effectively teach a drone to locate an object in a forest during summer, and then deploy the model in winter, with vastly different surroundings, or even in urban settings, with varied tasks such as seeking and following. This adaptability is made possible by the causal underpinnings of our solutions. These flexible algorithms could one day aid in decision-making based on data streams that change over time, such as medical diagnosis and autonomous driving applications.”

    A daunting challenge was at the forefront: Do machine-learning systems understand the task they are given from data when flying drones to an unlabeled object? And, would they be able to transfer their learned skill and task to new environments with drastic changes in scenery, such as flying from a forest to an urban landscape? What’s more, unlike the remarkable abilities of our biological brains, deep learning systems struggle with capturing causality, frequently over-fitting their training data and failing to adapt to new environments or changing conditions. This is especially troubling for resource-limited embedded systems, like aerial drones, that need to traverse varied environments and respond to obstacles instantaneously. 

    The liquid networks, in contrast, offer promising preliminary indications of their capacity to address this crucial weakness in deep learning systems. The team’s system was first trained on data collected by a human pilot, to see how they transferred learned navigation skills to new environments under drastic changes in scenery and conditions. Unlike traditional neural networks that only learn during the training phase, the liquid neural net’s parameters can change over time, making them not only interpretable, but more resilient to unexpected or noisy data. 

    In a series of quadrotor closed-loop control experiments, the drones underwent range tests, stress tests, target rotation and occlusion, hiking with adversaries, triangular loops between objects, and dynamic target tracking. They tracked moving targets, and executed multi-step loops between objects in never-before-seen environments, surpassing performance of other cutting-edge counterparts. 

    The team believes that the ability to learn from limited expert data and understand a given task while generalizing to new environments could make autonomous drone deployment more efficient, cost-effective, and reliable. Liquid neural networks, they noted, could enable autonomous air mobility drones to be used for environmental monitoring, package delivery, autonomous vehicles, and robotic assistants. 

    “The experimental setup presented in our work tests the reasoning capabilities of various deep learning systems in controlled and straightforward scenarios,” says MIT CSAIL Research Affiliate Ramin Hasani. “There is still so much room left for future research and development on more complex reasoning challenges for AI systems in autonomous navigation applications, which has to be tested before we can safely deploy them in our society.”

    “Robust learning and performance in out-of-distribution tasks and scenarios are some of the key problems that machine learning and autonomous robotic systems have to conquer to make further inroads in society-critical applications,” says Alessio Lomuscio, professor of AI safety in the Department of Computing at Imperial College London. “In this context, the performance of liquid neural networks, a novel brain-inspired paradigm developed by the authors at MIT, reported in this study is remarkable. If these results are confirmed in other experiments, the paradigm here developed will contribute to making AI and robotic systems more reliable, robust, and efficient.”

    Clearly, the sky is no longer the limit, but rather a vast playground for the boundless possibilities of these airborne marvels. 

    Hasani and PhD student Makram Chahine; Patrick Kao ’22, MEng ’22; and PhD student Aaron Ray SM ’21 wrote the paper with Ryan Shubert ’20, MEng ’22; MIT postdocs Mathias Lechner and Alexander Amini; and Rus.

    This research was supported, in part, by Schmidt Futures, the U.S. Air Force Research Laboratory, the U.S. Air Force Artificial Intelligence Accelerator, and the Boeing Co. More

  • 50 Shares159 Views

    in Data Management & Statistics

    Illuminating the money trail

    You may not know this, but the U.S. imposes a 12.5 percent import tariff on imported flashlights. However, for a product category the federal government describes as “portable electric lamps designed to function by their own source of energy, other than flashlights,” the import tariff is just 3.5 percent.

    At a glance, this seems inexplicable. Why is one kind of self-powered portable light taxed more heavily than another? According to MIT political science professor In Song Kim, a policy discrepancy like this often stems from the difference in firms’ political power, as well as the extent to which firms are empowered by global production networks. This is a subject Kim has spent years examining in detail, producing original scholarly results while opening up a wealth of big data about politics to the public.

    “We all understand companies as being important economic agents,” Kim says. “But companies are political agents, too. They are very important political actors.”

    In particular, Kim’s work has illuminated the effects of lobbying upon U.S. trade policy. International trade is often presented as an unalloyed good, opening up markets and fueling growth. Beyond that, trade issues are usually described at the industry level; we hear about what the agriculture lobby or auto industry wants. But in reality, different firms want different things, even within the same industry.

    As Kim’s work shows, most firms lobby for policies pertaining to specific components of their products, and trade policy consists heavily of carve-outs for companies, not industry-wide standards. Firms making non-flashlight portable lights, it would seem, are good at lobbying, but the benefits clearly do not carry over to all portable light makers, as long as products are not perfect substitutes for each other. Meanwhile, as Kim’s research also shows, lobbying helps firms grow faster in size, even as lobbying-influenced policies may slow down the economy as a whole.

    “All our existing theories suggest that trade policy is a public good, in the sense that the benefits of open trade, the gains from trade, will be enjoyed by the public and will benefit the country as a whole,” Kim says. “But what I’ve learned is that trade policies are very, very granular. It’s become obvious to me that trade is no longer a public good. It’s actually a private good for individual companies.”

    Kim’s work includes over a dozen published journal articles over the last several years, several other forthcoming research papers, and a book he is currently writing. At the same time, Kim has created a public database, LobbyView, which tracks money in U.S. politics extending back to 1999. LobbyView, as an important collection of political information, has research, educational, and public-interest applications, enabling others, in academia or outside it, to further delve into the topic.

    “I want to contribute to the scholarly community, and I also want to create a public [resource] for our MIT community [and beyond], so we can all study politics through it,” Kim says.

    Keeping the public good in sight

    Kim grew up in South Korea, in a setting where politics was central to daily life. Kim’s grandfather, Kim jae-soon, was the Speaker of the National Assembly in South Korea from 1988 through 1990 and an important figure in the country’s government.

    “I’ve always been fascinated by politics,” says Kim, who remembers prominent political figures dropping by the family home when he was young. One of the principal lessons Kim learned about politics from his grandfather, however, was not about proximity to power, but the importance of public service. The enduring lesson of his family’s engagement with politics, Kim says, is that “I truly believe in contributing to the public good.”

    Kim’s found his own way of contributing to the public good not as a politician but as a scholar of politics. Kim received his BA in political science from Yonsei University in Seoul but decided he wanted to pursue graduate studies in the U.S. He earned an MA in law and diplomacy from the Fletcher School of Tufts University, then an MA in political science at George Washington University. By this time, Kim had become focused on the quantitative analysis of trade policy; for his PhD work, he attended Princeton University and was awarded his doctorate in 2014, joining the MIT faculty that year.

    Among the key pieces of research Kim has published, one paper, “Political Cleavages within Industry: Firm-level Lobbying for Trade Liberalization,” published in the American Political Science Review and growing out of his dissertation research, helped show how remarkably specialized many trade policies are. As of 2017, the U.S. had almost 17,000 types of products it made tariff decisions about. Many of these are the component parts of a product; about two-thirds of international trade consists of manufactured components that get shipped around during the production process, rather than raw goods or finished products. That paper won the 2018 Michael Wallerstein Award for the best published article in political economy in the previous year.

    Another 2017 paper Kim co-authored, “The Charmed Life of Superstar Exporters,” from the Journal of Politics, provides more empirical evidence of the differences among firms within an industry. The “superstar” firms that are the largest exporters tend to lobby the most about trade politics; a firm’s characteristics reveal more about its preferences for open trade than the possibility that its industry as a whole will gain a comparative advantage internationally.

    Kim often uses large-scale data and computational methods to study international trade and trade politics. Still another paper he has co-authored, “Measuring Trade Profile with Granular Product-level Trade Data,” published in the American Journal of Political Science in 2020, traces trade relationships in highly specific terms. Looking at over 2 billion observations of international trade data, Kim developed an algorithm to group countries based on which products they import and export. The methodology helps researchers to learn about the highly different developmental paths that countries follow, and about the deepening international competition between countries such as the U.S. and China.

    At other times, Kim has analyzed who is influencing trade policy. His paper “Mapping Political Communities,” from the journal Political Analysis in 2021, looks at the U.S. Congress and uses mandatory reports filed by lobbyists to build a picture of which interests groups are most closely connected to which politicians.

    Kim has published all his papers while balancing both his scholarly research and the public launch of LobbyView, which occurred in 2018. He was awarded tenure by MIT in the spring of 2022. Currently he is an associate professor in the Department of Political Science and a faculty affiliate of the Institute for Data, Systems, and Society.

    By the book

    Kim has continued to explore firm-level lobbying dynamics, although his recent research runs in a few directions. In a 2021 working paper, Kim and co-author Federico Huneeus of the Central Bank of Chile built a model estimating that eliminating lobbying in the U.S. could increase productivity by as much as 6 percent.

    “Political rents [favorable policies] given to particular companies might introduce inefficiencies or a misallocation of resources in the economy,” Kim says. “You could allocate those resources to more productive although politically inactive firms, but now they’re given to less productive and yet politically active big companies, increasing market concentration and monopolies.”

    Kim is on sabbatical during the 2022-23 academic year, working on a book about the importance of firms’ political activities in trade policymaking. The book will have an expansive timeframe, dating back to ancient times, which underscores the salience of trade policy across eras. At the same time, the book will analyze the distinctive features of modern trade politics with deepening global production networks.

    “I’m trying to allow people to learn about the history of trade politics, to show how the politics have changed over time,” Kim says. “In doing that, I’m also highlighting the importance of firm-to-firm trade and the emergence of new trade coalitions among firms in different countries and industries that are linked through the global production chain.”

    While continuing his own scholarly research, Kim still leads LobbyView, which he views both as a big data resource for any scholars interested in money in politics and an excellent teaching resource for his MIT classes, as students can tap into it for projects and papers. LobbyView contains so much data, in fact, that part of the challenge is finding ways to mine it effectively.

    “It really offers me an opportunity to work with MIT students,” Kim says of LobbyView. “What I think I can contribute is to bring those technologies to our understanding of politics. Having this unique data set can really allow students here to use technology to learn about politics, and I believe that fits the MIT identity.” More