Interviewer: Jillian York

Benjamin Ismail is the Campaign and Advocacy Director for GreatFire, where he leads efforts to expose the censorship apparatus of authoritarian regimes worldwide. He also runs/oversees the App Censorship Project, including the AppleCensorship.com and GoogleCensorship.org platforms, which track mobile app censorship globally. From 2011 to 2017, Benjamin headed the Asia-Pacific desk at Reporters Without Borders (RSF).

Jillian York: Hi Benjamin, it's great to chat with you. We got to meet at the Global Gathering recently and we did a short video there and it was wonderful to get to know you a little bit. I'm going to start by asking you my first basic question: What does free speech or free expression mean to you?

Benjamin Ismail: Well, it starts with a very, very big question. What I have in mind is a cliche answer, but it's what I genuinely believe. I think about all freedoms. So when you say free expression, free speech, or freedom of information or Article 19, all of those concepts are linked together, I immediately think of all human rights at once. Because what I have seen during my current or past work is how that freedom is really the cornerstone of all freedom. If you don’t have that, you can’t have any other freedom. If you don’t have freedom of expression, if you don't have journalism, you don't have pluralism of opinions—you have self-censorship.

You have realities, violations, that exist but are not talked about, and are not exposed, not revealed, not tackled, and nothing is really improved without that first freedom. I also think about Myanmar because I remember going there in 2012, when the country had just opened after the democratic revolution. We got the chance to meet with many officials, ministers, and we got to tell them that they should start with that because their speech was “don’t worry, don’t raise freedom of speech, freedom of the press will come in due time.”

And we were saying “no, that’s not how it works!” It doesn’t come in due time when other things are being worked on. It starts with that so you can work on other things. And so I remember very well those meetings and how actually, unfortunately, the key issues that re-emerged afterwards in the country were precisely due to the fact that they failed to truly implement free speech protections when the country started opening.

JY: What was your path to this work?

BI: This is a multi-faceted answer. So, I was studying Chinese language and civilization at the National Institute of Oriental Languages and Civilizations in Paris along with political science and international law. When I started that line of study, I considered maybe becoming a diplomat…that program led to preparing for the exams required to enter the diplomatic corps in France.

But I also heard negative feedback on the Ministry of Foreign Affairs and, notably, first-hand testimonies from friends and fellow students who had done internships there. I already knew that I had a little bit of an issue with authority. My experience as an assistant at Reporters Without Borders challenged the preconceptions I had about NGOs and civil society organizations in general. I was a bit lucky to come at a time when the organization was really trying to find its new direction, its new inspiration. So it a brief phase where the organization itself was hungry for new ideas.

Being young and not very experienced, I was invited to share my inputs, my views—among many others of course. I saw that you can influence an organization’s direction, actions, and strategy, and see the materialization of those strategic choices. Such as launching a campaign, setting priorities, and deciding how to tackle issues like freedom of information, and the protection of journalists in various contexts.

That really motivated me and I realized that I would have much less to say if I had joined an institution such as the Ministry of Foreign Affairs. Instead, I was part of a human-sized group, about thirty-plus employees working together in one big open space in Paris.

After that experience I set my mind on joining the civil society sector, focusing on freedom of the press. on journalistic issues, you get to touch on many different issues in many different regions, and I really like that. So even though it’s kind of monothematic, it's a single topic that's encompassing everything at the same time.

I was dealing with safety issues for Pakistani journalists threatened by the Taliban. At the same time I followed journalists pressured by corporations such as TEPCO and the government in Japan for covering nuclear issues. I got to touch on many topics through the work of the people we were defending and helping. That’s what really locked me onto this specific human right.

 I already had my interest when I was studying in political and civil rights, but after that first experience, at the end of 2010, I went to China and got called by Reporters Without Borders. They told me that the head of the Asia desk was leaving and invited me to apply for the position. At that time, I was in Shanghai, working to settle down there. The alternative was accepting a job that would take me back to Paris but likely close the door on any return to China. Once you start giving interviews to outlets like the BBC and CNN, well… you know how that goes—RSF was not viewed favorably in many countries. Eventually, I decided it was a huge opportunity, so I accepted the job and went back to Paris, and from then on I was fully committed to that issue.

 JY: For our readers, tell us what the timeline of this was.

 BI: I finished my studies in 2009. I did my internship with Reporters Without Borders that year and continued to work pro bono for the organization on the Chinese website in 2010. Then I went to China, and in January 2011, I was contacted by Reporters without Borders about the departure of the former head of the Asia Pacific Desk.

I did my first and last fact-finding mission in China, and went to Beijing. I met the artist Ai Weiwei in Beijing just a few weeks before he was arrested, around March 2011, and finally flew back to Paris and started heading the Asia desk. I left the organization in 2017. 

JY: Such an amazing story. I’d love to hear more about the work that you do now.

 BI: The story of the work I do now actually starts in 2011. That was my first year heading the Asia Pacific Desk. That same year, a group of anonymous activists based in China started a group called GreatFire. They launched their project with a website where you can type any URL you want and that website will test the connection from mainland China to that URL and tell you know if it’s accessible or blocked. They also kept the test records so that you can look at the history of the blocking of a specific website, which is great. That was GreatFire’s first project for monitoring web censorship in mainland China.

We started exchanging information, working on the issue of censorship in China. They continued to develop more projects which I tried to highlight as well. I also helped them to secure some funding. At the very beginning, they were working on these things as a side job. And progressively they managed to get some funding, which was very difficult because of the anonymity.

One of the things I remember is that I helped them get some funding from the EU through a mechanism called “Small Grants”, where every grant would be around €20- 30,000. The EU, you know, is a bureaucratic entity and they were demanding some paperwork and documents. But I was telling them that they wouldn’t be able to get the real names of the people working at GreatFire, but that they should not be concerned about that because, what they wanted was to finance that tool. So if we were to show them that the people they were going to send the money to were actually the people controlling that website, then it would be fine. And so we featured a little EU logo just for one day, I think on the footer of the website so they could check that. And that’s how we convinced the EU to support GreatFire for that work. Also, there's this tactic called “Collateral Freedom” that GreatFire uses very well.

The idea is that you host sensitive content on HTTPS servers that belong to companies which also operate inside China and are accessible there. Because it’s HTTPS, the connection is encrypted, so the authorities can’t just block a specific page—they can’t see exactly which page is being accessed. To block it, they’d have to block the entire service. Now, they can do that, but it comes at a higher political and economic cost, because it means disrupting access to other things hosted on that same service—like banks or major businesses. That’s why it’s called “collateral freedom”: you’re basically forcing the authorities to risk broader collateral damage if they want to censor your content.

When I was working for RSF, I proposed that we replicate that tactic on the 12th of March—that's the World Day against Cyber Censorship. We had the habit of publishing what we called the “enemies of the Internet” report, where we would highlight and update the situation on the countries which were carrying out the harshest repression online; countries like Iran, Turkmenistan, North Korea, and of course, China. I suggested in a team meeting: “what if we highlighted the good guys? Maybe we could highlight 10 exiled media and use collateral freedom to uncensor those. And so we did: some Iranian media, Egyptian media, Chinese media, Turkmen media were uncensored using mirrors hosted on https servers owned by big, and thus harder to block, companies...and that’s how we started to do collateral freedom and it continued to be an annual thing.

I also helped in my personal capacity, including after I left Reporters Without Borders. After I left RSF, I joined another NGO focusing on China, which I knew also from my time at RSF. I worked with that group for a year and a half; GreatFire contacted me to work on a website specifically. So here we are, at the beginning of 2020, they had just started this website called Applecensorship.com that allowed users to test availability of any app in any of Apple’s 175 App Stores worldwide They needed a better website—one that allowed advocacy content—for that tool.

The idea was to make a website useful for academics doing research, journalists investigating app store censorship and control and human rights NGOs, civil society organizations interested in the availability of any tools. Apple’s censorship in China started quickly after the company entered the Chinese market, in 2010.

In 2013, one of the projects by GreatFire which had been turned into an iOS app was removed by Apple 48 hours after its release on the App Store, at the demand of the Chinese authorities. That project was Free Weibo, which is a website which features censored posts from Weibo, the Chinese equivalent of Twitter—we crawl social media and detect censored posts and republish them on the site. In 2017 it was reported that Apple had removed all VPNs from the Chinese app store.

So between that episode in 2013, and the growing censorship of Apple in China (and in other places too) led to the creation of AppleCensorship in 2019. GreatFire asked me to work on that website. The transformation into an advocacy platform was successful. I then started working full time on that project, which has since evolved into the App Censorship Project, which includes another website, googlecensorship.org (offering features similar to Applecensorship.com but for the 224 Play Stores worldwide). In the meantime, I became the head of campaigns and advocacy, because of my background at RSF.  

 JY: I want to ask you, looking beyond China, what are some other places in the world that you're concerned about at the moment, whether on a professional basis, but also maybe just as a person. What are you seeing right now in terms of global trends around free expression that worry you?

BI: I think, like everyone else, that what we're seeing in Western democracies—in the US and even in Europe—is concerning. But I'm still more concerned about authoritarian regimes than about our democracies. Maybe it's a case of not learning my lesson or of naive optimism, but I'm still more concerned about China and Russia than I am about what I see in France, the UK, or the US.

There has been some recent reporting about China developing very advanced censorship and surveillance technologies and exporting them to other countries like Myanmar and Pakistan. What we’re seeing in Russia—I’m not an expert on that region, but we heard experts saying back in 2022 that Russia was trying to increase its censorship and control, but that it couldn’t become like China because China had exerted control over its internet from the very beginning: They removed Facebook back in 2009, then Google was pushed away by the authorities (and the market). And the Chinese authorities successfully filled the gaps left by the absence of those foreign Western companies.

Some researchers working on Russia were saying that it wasn’t really possible for Russia to do what China had done because it was unprepared and that China had engineered it for more than a decade. What we are seeing now is that Russia is close to being able to close its Internet, to close the country, to replace services by its own controlled ones. It’s not identical, but it’s also kind of replicating what China has been doing. And that’s a very sad observation to make.

 Beyond the digital, the issue of how far Putin is willing to go in escalating concerns. As a human being and an inhabitant of the European continent, I’m concerned by the ability of a country like Russia to isolate itself while waging a war. Russia is engaged in a real war and at the same time is able to completely digitally close down the country. Between that and the example of China exporting censorship, I’m not far from thinking that in ten or twenty years we’ll have a completely splintered internet.

JY: Do you feel like having a global perspective like this has changed or reshaped your views in any way?

BI: Yes, in the sense that when you start working with international organizations, and you start hearing about the world and how human rights are universal values, and you get to meet people and go to different countries, you really get to experience how universal those freedoms and aspirations are. When I worked RSF and lobbied governments to pass a good law or abolish a repressive one, or when I worked on a case of a jailed journalist or blogger, I got to talk to authorities and to hear weird justifications from certain governments (not mentioning any names but Myanmar and Vietnam) like “those populations are different from the French” and I would receive pushback that the ideas of freedoms I was describing were not applicable to their societies. It’s a bit destabilizing when you hear that for the first time. But as you gain experience, you can clearly explain why human rights are universal and why different populations shouldn’t be ruled differently when it comes to human rights.

Everyone wants to be free. This notion of “universality” is comforting because when you’re working for something universal, the argument is there. The freedoms you defend can’t be challenged in principle, because everyone wants them. If governments and authorities really listened to their people, they would hear them calling for those rights and freedoms.

Or that’s what I used to think. Now we hear this growing rhetoric that we (people from the West) are exporting democracy, that it’s a western value, and not a universal one. This discourse, notably developed by Xi Jinping in China, “Western democracy” as a new concept— is a complete fallacy. Democracy was invented in the West, but democracy is universal. Unfortunately, I now believe that, in the future, we will have to justify and argue much more strongly for the universality of concepts like democracy, human rights and fundamental freedoms. 

JY: Thank you so much for this insight. And now for our final question: Do you have a free speech hero?

BI: No.

JY: No? No heroes? An inspiration maybe.

BI: On the contrary, I’ve been disappointed so much by certain figures that were presented as human rights heroes…Like Aung San Suu Kyi during the Rohingya crisis, on which I worked when I was at RSF.

Myanmar officially recognizes 135 ethnic groups, but somehow this one additional ethnic minority (the Rohingya) is impossible for them to accept. It’s appalling. It’s weird to say, but some heroes are not really good people either. Being a hero is doing a heroic action, but people who do heroic actions can also do very bad things before or after, at a different level. They can be terrible persons, husbands or friends and be a “human rights” hero at the same time.

Some people really inspired me but they’re not public figures. They are freedom fighters, but they are not “heroes”. They remain in the shadows. I know their struggles; I see their determination, their conviction, and how their personal lives align with their role as freedom fighters. These are the people who truly inspire me.

Around 5,000 years ago, people living in what is now Iran began extracting copper from rock by processing ore, an activity known as smelting. This monumental shift gave them a powerful new technology and may have marked the birth of metallurgy. Soon after, people in different parts of the world were using copper and bronzes (alloys of copper and tin, or copper and arsenic) to produce decorative objects, weapons, tools, and more.

Studying how humans produced such objects is challenging because little evidence still exists, and artifacts that have survived are carefully guarded and preserved.

In a paper published in PLOS One, MIT researchers demonstrated a new approach to uncovering details of some of the earliest metallurgical processes. They studied 5,000-year-old slag waste, a byproduct of smelting ore, using techniques including X-ray computed tomography, also known as CT scanning. In their paper, they show how this noninvasive imaging technique, which has primarily been used in the medical field, can reveal fine details about structures within the pieces of ancient slag.

“Even though slag might not give us the complete picture, it tells stories of how past civilizations were able to refine raw materials from ore and then to metal,” says postdoc Benjamin Sabatini. “It speaks to their technological ability at that time, and it gives us a lot of information. The goal is to understand, from start to finish, how they accomplished making these shiny metal products.”

In the paper, Sabatini and senior author Antoine Allanore, a professor of metallurgy and the Heather N. Lechtman Professor of Materials Science and Engineering, combined CT scanning with more traditional methods of studying ancient artifacts, including cutting the samples for further analysis. They demonstrated that CT scanning could be used to complement those techniques, revealing pores and droplets of different materials within samples. This information could shed light on the materials used by and the technological sophistication of some of the first metallurgists on Earth.

“The Early Bronze Age is one of the earliest reported interactions between mankind and metals,” says Allanore, who is also director of MIT’s Center for Materials Research in Archaeology and Ethnology. “Artifacts in that region at that period are extremely important in archaeology, yet the materials themselves are not very well-characterized in terms of our understanding of the underlying materials and chemical processes. The CT scan approach is a transformation of traditional archaeological methods of determining how to make cuts and analyze samples.”

A new tool in archaeology

Slag is produced as a molten hot liquid when ores are heated to produce metal. The slag contains other constituent minerals from the ore, as well as unreacted metals, which are commonly mixed with additives like limestone. In the mixture, the slag is less dense than the metal, so it can rise and be removed, solidifying like lava as it cools.

“Slag waste is chemically complex to interpret because in our modern metallurgical practices it contains everything not desired in the final product — in particular, arsenic, which is a key element in the original minerals for copper,” says Allanore. “There’s always been a question in archaeometallurgy if we can use arsenic and similar elements in these remains to learn something about the metal production process. The challenge here is that these minerals, especially arsenic, are very prone to dissolution and leaching, and therefore their environmental stability creates additional problems in terms of interpreting what this object was when it was being made 6,000 years ago.”

For the study, the researchers used slag from an ancient site known as Tepe Hissar in Iran. The slag has previously been dated to the period between 3100 and 2900 BCE and was loaned by the Penn Museum to Allanore for study in 2022.

“This region is often brought up as one of the earliest places where evidence of copper processing and object production might have happened,” Allanore explains. “It is very well-preserved, and it’s an early example of a site with long-distance trade and highly organized society. That’s why it’s so important in metallurgy.”

The researchers believe this is the first attempt to study ancient slag using CT scanning, partly because medical-grade scanners are expensive and primarily located in hospitals. The researchers overcame these challenges by working with a local startup in Cambridge that makes industrial CT scanners. They also used the CT scanner on MIT’s campus.

“It was really out of curiosity to see if there was a better way to study these objects,” Sabatini said.

In addition to the CT scans, the researchers used more conventional archaeological analytical methods such as X-ray fluorescence, X-ray diffraction, and optical and scanning electron microscopy. The CT scans provided a detailed overall picture of the internal structure of the slag and the location of interesting features like pores and bits of different materials, augmenting the conventional techniques to impart more complete information about the inside of samples.

They used that information to decide where to section their sample, noting that researchers often guess where to section samples, unsure even which side of the sample was originally facing up or down.

“My strategy was to zero in on the high-density metal droplets that looked like they were still intact, since those might be most representative of the original process,” Sabatini says. “Then I could destructively analyze the samples with a single slice. The CT scanning shows you exactly what is most interesting, as well as the general layout of things you need to study.”

Finding stories in slag

In previous studies, some slag samples from the Tepe Hissar site contained copper and thus seemed to fit the narrative that they resulted from the production of copper, while others showed no evidence of copper at all.

The researchers found that CT scanning allowed them to characterize the intact droplets that contained copper. It also allowed them to identify where gases evolved, forming voids that hold information about how the slags were produced.

Other slags at the site had previously been found to contain small metallic arsenide compounds, leading to disagreements about the role of arsenic in early metal production. The MIT researchers found that arsenic existed in different phases across their samples and could move within the slag or even escape the slag entirely, making it complicated to infer metallurgical processes from the study of arsenic alone.

Moving forward, the researchers say CT scanning could be a powerful tool in archaeology to unravel complex ancient materials and processes.

“This should be an important lever for more systematic studies of the copper aspect of smelting, and also for continuing to understand the role of arsenic,” Allanore says. “It allows us to be cognizant of the role of corrosion and the long-term stability of the artifacts to continue to learn more. It will be a key support for people who want to investigate these questions.”

This work was supported, in part, by the MIT Human Insight Collaborative (MITHIC).

Social media has been a familiar, even mundane, part of life for nearly two decades. It can be easy to forget it was not always that way.

In 2008, social media was just emerging into the mainstream. Facebook reached 100 million users that summer. And a singular candidate was integrating social media into his political campaign: Barack Obama. His campaign’s use of social media was so bracingly innovative, so impactful, that it was viewed by journalist David Talbot and others as the strategy that enabled the first term Senator to win the White House...

The destruction caused by the summer storms was enough that past presidents likely would have approved requests for federal assistance.

The state's top emergency official also is under discussion to lead FEMA. The agency's acting chief resigned Monday after a six-month stint.

In the Biden era, countries interested in clean energy “were motivated to buy things from the U.S.,” an African official says. But now Beijing has few rivals.

Liu Zhenmin also defended Beijing’s own climate efforts as “very ambitious.”

British and Brazilian officials hope for a change of heart after this month’s budget.

Business groups say the laws violate companies' First Amendment rights.

The NYU School of Law’s Institute for Policy Integrity says the costs of deregulation far exceeds the benefits.

AI has fueled a boom in new weather prediction tools, which are starting to replace forecasts that had been generated by supercomputers.

Earth and rocks collapsed on a bus in Khanh Hoa province Sunday night, killing six and trapping many passengers, state media reported.

The operation, which involves dispersing chemicals into clouds, takes place as Iran faces its worst drought in decades.

The nation, a major importer of thermal coal, will join about 60 countries in the Powering Past Coal Alliance.

Feeling thirsty? Why not tap into the air? Even in desert conditions, there exists some level of humidity that, with the right material, can be soaked up and squeezed out to produce clean drinking water. In recent years, scientists have developed a host of promising sponge-like materials for this “atmospheric water harvesting.”

But recovering the water from these materials usually requires heat — and time. Existing designs rely on heat from the sun to evaporate water from the materials and condense it into droplets. But this step can take hours or even days. 

Now, MIT engineers have come up with a way to quickly recover water from an atmospheric water harvesting material. Rather than wait for the sun to evaporate water out, the team uses ultrasonic waves to shake the water out.

The researchers have developed an ultrasonic device that vibrates at high frequency. When a water-harvesting material, known as a “sorbent,” is placed on the device, the device emits ultrasound waves that are tuned to shake water molecules out of the sorbent. The team found that the device recovers water in minutes, versus the tens of minutes or hours required by thermal designs.

Unlike heat-based designs, the device does require a power source. The team envisions that the device could be powered by a small solar cell, which could also act as a sensor to detect when the sorbent is full. It could also be programmed to automatically turn on whenever a material has harvested enough moisture to be extracted. In this way, a system could soak up and shake out water from the air over many cycles in a single day.

“People have been looking for ways to harvest water from the atmosphere, which could be a big source of water particularly for desert regions and places where there is not even saltwater to desalinate,” says Svetlana Boriskina, principal research scientist in MIT’s Department of Mechanical Engineering. “Now we have a way to recover water quickly and efficiently.”

Boriskina and her colleagues report on their new device in a study appearing today in the journal Nature Communications. The study’s first author is Ikra Iftekhar Shuvo, an MIT graduate student in media arts and sciences, along with Carlos Díaz-Marín, Marvin Christen, Michael Lherbette, and Christopher Liem.

Precious hours

Boriskina’s group at MIT develops materials that interact with the environment in novel ways. Recently, her group explored atmospheric water harvesting (AWH), and ways that materials can be designed to efficiently absorb water from the air. The hope is that, if they can work reliably, AWH systems would be of most benefit to communities where traditional sources of drinking water — and even saltwater — are scarce.

Like other groups, Boriskina’s lab had generally assumed that an AWH system in the field would absorb moisture during the night, and then use the heat from the sun during the day to naturally evaporate the water and condense it for collection.

“Any material that’s very good at capturing water doesn’t want to part with that water,” Boriskina explains. “So you need to put a lot of energy and precious hours into pulling water out of the material.”

She realized there could be a faster way to recover water after Ikra Shuvo joined her group. Shuvo had been working with ultrasound for wearable medical device applications. When he and Boriskina considered ideas for new projects, they realized that ultrasound could be a way to speed up the recovery step in atmospheric water harvesting.

“It clicked: We have this big problem we’re trying to solve, and now Ikra seemed to have a tool that can be used to solve this problem,” Boriskina recalls.

Water dance

Ultrasound, or ultrasonic waves, are acoustic pressure waves that travel at frequencies of over 20 kilohertz (20,000 cycles per second). Such high-frequency waves are not visible or audible to humans. And, as the team found, ultrasound vibrates at just the right frequency to shake water out of a material.

“With ultrasound, we can precisely break the weak bonds between water molecules and the sites where they’re sitting,” Shuvo says. “It’s like the water is dancing with the waves, and this targeted disturbance creates momentum that releases the water molecules, and we can see them shake out in droplets.”

Shuvo and Boriskina designed a new ultrasonic actuator to recover water from an atmospheric water harvesting material. The heart of the device is a flat ceramic ring that vibrates when voltage is applied. This ring is surrounded by an outer ring that is studded with tiny nozzles. Water droplets that shake out of a material can drop through the nozzle and into collection vessels attached above and below the vibrating ring.

They tested the device on a previously designed atmospheric water harvesting material. Using quarter-sized samples of the material, the team first placed each sample in a humidity chamber, set to various humidity levels. Over time, the samples absorbed moisture and became saturated. The researchers then placed each sample on the ultrasonic actuator and powered it on to vibrate at ultrasonic frequencies. In all cases, the device was able to shake out enough water to dry out each sample in just a few minutes.

The researchers calculate that, compared to using heat from the sun, the ultrasonic design is 45 times more efficient at extracting water from the same material.

“The beauty of this device is that it’s completely complementary and can be an add-on to almost any sorbent material,” says Boriskina, who envisions a practical, household system might consist of a fast-absorbing material and an ultrasonic actuator, each about the size of a window. Once the material is saturated, the actuator would briefly turn on, powered by a solar cell, to shake out the water. The material would then be ready to harvest more water, in multiple cycles throughout a single day.

“It’s all about how much water you can extract per day,” she says. “With ultrasound, we can recover water quickly, and cycle again and again. That can add up to a lot per day.”

This work was supported, in part, by the MIT Abdul Latif Jameel Water and Food Systems Lab and the MIT-Israel Zuckerman STEM Fund.

This work was carried out in part by using MIT.nano and ISN facilities at MIT.

Nature Climate Change, Published online: 18 November 2025; doi:10.1038/s41558-025-02500-0

Climate change threatens biodiversity, but the transfer of genes between species via hybridization can enhance climate resilience. This research demonstrates that hybrid mountain birds show reduced climate vulnerability, highlighting how maintaining natural gene flow can mitigate extinction risks and is crucial for conserving species with narrow environmental tolerances.

Nature Climate Change, Published online: 18 November 2025; doi:10.1038/s41558-025-02480-1

The authors couple calculations of historical heatwave intensity at present and future global temperatures with exposure–response functions to quantify mortality from extreme heat events in Europe. They project tens of thousands of excess deaths, with limited attenuation from existing adaptations.

Determining the least expensive path for a new subway line underneath a metropolis like New York City is a colossal planning challenge — involving thousands of potential routes through hundreds of city blocks, each with uncertain construction costs. Conventional wisdom suggests extensive field studies across many locations would be needed to determine the costs associated with digging below certain city blocks.

Because these studies are costly to conduct, a city planner would want to perform as few as possible while still gathering the most useful data for making an optimal decision.

With almost countless possibilities, how would they know where to start?

A new algorithmic method developed by MIT researchers could help. Their mathematical framework provably identifies the smallest dataset that guarantees finding the optimal solution to a problem, often requiring fewer measurements than traditional approaches suggest.

In the case of the subway route, this method considers the structure of the problem (the network of city blocks, construction constraints, and budget limits) and the uncertainty surrounding costs. The algorithm then identifies the minimum set of locations where field studies would guarantee finding the least expensive route. The method also identifies how to use this strategically collected data to find the optimal decision.

This framework applies to a broad class of structured decision-making problems under uncertainty, such as supply chain management or electricity network optimization.

“Data are one of the most important aspects of the AI economy. Models are trained on more and more data, consuming enormous computational resources. But most real-world problems have structure that can be exploited. We’ve shown that with careful selection, you can guarantee optimal solutions with a small dataset, and we provide a method to identify exactly which data you need,” says Asu Ozdaglar, Mathworks Professor and head of the MIT Department of Electrical Engineering and Computer Science (EECS), deputy dean of the MIT Schwarzman College of Computing, and a principal investigator in the Laboratory for Information and Decision Systems (LIDS).

Ozdaglar, co-senior author of a paper on this research, is joined by co-lead authors Omar Bennouna, an EECS graduate student, and his brother Amine Bennouna, a former MIT postdoc who is now an assistant professor at Northwestern University; and co-senior author Saurabh Amin, co-director of Operations Research Center, a professor in the MIT Department of Civil and Environmental Engineering, and a principal investigator in LIDS. The research will be presented at the Conference on Neural Information Processing Systems.

An optimality guarantee

Much of the recent work in operations research focuses on how to best use data to make decisions, but this assumes these data already exist.

The MIT researchers started by asking a different question — what are the minimum data needed to optimally solve a problem? With this knowledge, one could collect far fewer data to find the best solution, spending less time, money, and energy conducting experiments and training AI models.

The researchers first developed a precise geometric and mathematical characterization of what it means for a dataset to be sufficient. Every possible set of costs (travel times, construction expenses, energy prices) makes some particular decision optimal. These “optimality regions” partition the decision space. A dataset is sufficient if it can determine which region contains the true cost.

This characterization offers the foundation of the practical algorithm they developed that identifies datasets that guarantee finding the optimal solution.

Their theoretical exploration revealed that a small, carefully selected dataset is often all one needs.

“When we say a dataset is sufficient, we mean that it contains exactly the information needed to solve the problem. You don’t need to estimate all the parameters accurately; you just need data that can discriminate between competing optimal solutions,” says Amine Bennouna.

Building on these mathematical foundations, the researchers developed an algorithm that finds the smallest sufficient dataset.

Capturing the right data

To use this tool, one inputs the structure of the task, such as the objective and constraints, along with the information they know about the problem.

For instance, in supply chain management, the task might be to reduce operational costs across a network of dozens of potential routes. The company may already know that some shipment routes are especially costly, but lack complete information on others.

The researchers’ iterative algorithm works by repeatedly asking, “Is there any scenario that would change the optimal decision in a way my current data can't detect?” If yes, it adds a measurement that captures that difference. If no, the dataset is provably sufficient.

This algorithm pinpoints the subset of locations that need to be explored to guarantee finding the minimum-cost solution.

Then, after collecting those data, the user can feed them to another algorithm the researchers developed which finds that optimal solution. In this case, that would be the shipment routes to include in a cost-optimal supply chain.

“The algorithm guarantees that, for whatever scenario could occur within your uncertainty, you’ll identify the best decision,” Omar Bennouna says.

The researchers’ evaluations revealed that, using this method, it is possible to guarantee an optimal decision with a much smaller dataset than would typically be collected.

“We challenge this misconception that small data means approximate solutions. These are exact sufficiency results with mathematical proofs. We’ve identified when you’re guaranteed to get the optimal solution with very little data — not probably, but with certainty,” Amin says.

In the future, the researchers want to extend their framework to other types of problems and more complex situations. They also want to study how noisy observations could affect dataset optimality.

“I was impressed by the work’s originality, clarity, and elegant geometric characterization. Their framework offers a fresh optimization perspective on data efficiency in decision-making,” says Yao Xie, the Coca-Cola Foundation Chair and Professor at Georgia Tech, who was not involved with this work.

The state's top emergency official also is under discussion to lead FEMA. The agency's acting chief resigned Monday after a six-month stint.

Researchers at MIT Lincoln Laboratory have developed a first-of-its-kind hydrophone built around a simple, commercially available microphone. The device, leveraging a common microfabrication process known as microelectromechanical systems (MEMS), is significantly smaller and less expensive than current hydrophones, yet has equal or exceeding sensitivity. The hydrophone could have applications for the U.S. Navy, as well as industry and the scientific research community.

"Given the broad interest from the Navy in low-cost hydrophones, we were surprised that this design had not been pursued before," says Daniel Freeman, who leads this work in the Advanced Materials and Microsystems Group. "Hydrophones are critical for undersea sensing in a variety of applications and platforms. Our goal was to demonstrate that we could develop a device at reduced size and cost without sacrificing performance."

Essentially an underwater microphone, a hydrophone is an instrument that converts sound waves into electrical signals, allowing us to "hear" and record sounds in the ocean and other bodies of water. These signals can later be analyzed and interpreted, providing valuable information about the underwater environment.

MEMS devices are incredibly small systems — ranging from a few millimeters down to microns (smaller than a human hair) — with tiny moving parts. They are used in a variety of sensors, including microphones, gyroscopes, and accelerometers. The small size of MEMS sensors has made them crucial in various applications, from smartphones to medical devices. Currently, no commercially available hydrophones utilize MEMS technology, so the team set out to understand whether such a design was possible.

With funding from the Office of the Under Secretary of War for Research and Engineering to develop a novel hydrophone, the team first planned to use microfabrication, an area of expertise at the laboratory, to develop their device. However, that approach proved to be too costly and involved to pursue. This obstacle led the team to pivot and build their hydrophone around a commercially available MEMS microphone. "We had to come up with an inexpensive alternative without giving up performance, and this is what led us to build the design around a microphone, which to our knowledge is a novel approach," Freeman explains.

In collaboration with researchers at Tufts University, as well as industry partners SeaLandAire Technologies and Navmar Applied Sciences Corp., the team made the hydrophone by encapsulating the MEMS microphone in a polymer with low permeability to water while leaving an air cavity around the microphone’s diaphragm (the component of the microphone that vibrates in response to sound waves). One key challenge that they faced was the possibility of losing too much signal to the packaging and the air cavity around the MEMS microphone. After a substantial amount of simulation, design iterations, and testing, the team found that the signal lost from incorporating air into the device was compensated for by the very high sensitivity of the MEMS microphone itself. As a result, the device was able to perform at a sensitivity comparable to high-end hydrophones at depths down to 400 feet and temperatures as low as 40 degrees Fahrenheit. To date, the collaborative effort has involved computational modeling, system electronics design and fabrication, prototype unit manufacturing, and calibrator and pool testing.

In July, eight researchers traveled to Seneca Lake in New York to test a variety of devices. The hydrophones were lowered to increasing depths in the water — 100 feet at first, then incrementally lower down to 400 feet. At each depth, acoustic signals of varying frequencies were transmitted for the instrument to record. The transmitted signals were calibrated to a known level so they could then measure the actual sensitivity of the hydrophones across different frequencies. When the sound hits the hydrophone’s diaphragm, it generates an electrical signal that is amplified, digitized, and transmitted to a recording device at the surface for post-test data analysis. The team utilized both commercial underwater cables as well as Lincoln Laboratory’s fiber-based sensing arrays.

"This was our first field test in deep water, and therefore it was an important milestone in demonstrating the ability to operate in a realistic environment, rather than the water chambers that we’d been using," Freeman says. "Our hope was that the performance of our device would match what we've seen in our water tank, where we tested at high hydrostatic pressure across a range of frequencies. In other words, we hoped this test would provide results that confirm our predictions based on lab-based testing."

The test results were excellent, showing that the sensitivity and the signal-to-noise was within a few decibels of the quietest ocean state, known as sea state zero. Moreover, this performance was achieved in deep water, at 400 feet, and with very low temperatures, around 40 degrees Fahrenheit.

The prototype hydrophone has applications across a wide variety of commercial and military use-cases owing to its small size, efficient power draw, and low cost.

"We're in discussion with the Department of War about transitioning this technology to the U.S. government and industry," says Freeman. "There is still some room for optimizing the design, but we think we've demonstrated that this hydrophone has the key benefits of being robust, high performance, and very low cost."