Suramya's Blog : Welcome to my crazy life…

August 6, 2020

Thoughts on Cybercrime in the Covid world

Filed under: Computer Security,My Thoughts — Suramya @ 1:08 PM

The Cyber Security industry has seen a massive boost during the current pandemic, with users working remotely for the first time and permissions granted on the fly the Security teams in the enterprise have been working round the clock to ensure critical data and systems are secure. But due to the general chaos of Covid combined with the need to keep businesses running there are systems that have been less than optimally configured.

All this gives us the impression that the Cybercrime world must be thriving in the current environment. But apparently that is not always the case, the Cambridge Cybercrime Centre has released a series of reports on how the Pandemic has impacted cybercrime. The reports are a fascinating read as they show how even the criminals are facing hardships due to the pandemic. For example, below is an extract from the report on the impact on International drug trade due to the shipping disruptions caused by lockdowns.

“The initial wave of COVID lockdowns in China caused substantial disruption to international shipping,compounded by the subsequent lockdowns in the rest of the world. Despite their ‘online’ character, drugscryptomarkets (online markets for legal and illegal drugs which are accessed securely through anonymitynetworks such as Tor) are reliant on the postal and shipping services for the delivery of drugs and precursorsto suppliers and end users. We have observed, in our scraped datasets of illicit online forums and discussionboards, evidence of significant disruption of these pathways, and a range of effects on these illicit markets.At the initial peak of lockdown measures, shipping times (especially in international routes which passedthrough China) were being routinely delayed by up to three months (as reported in cryptomarket discussions).This caused significant friction to international orders for postal drug delivery, with many dealers reportingthat they were switching to orders within the same nation only, and others struggling to source supply.”

Brian Kerbs from Kerbs on Security wrote a comprehensive article on How Cybercriminals are Weathering COVID-19 and its worth a read as well.

But apparently a number of criminal reshipping services are reporting difficulties due to the increased wait time when calling FedEx or UPS (to divert carded goods that merchants end up shipping to the cardholder’s address instead of to the mule’s). In response, these operations are raising their prices and warning of longer shipping times, which in turn could hamper the activities of other actors who depend on those services.

That’s according to Intel 471, a cyber intelligence company that closely monitors hundreds of online crime forums. In a report published today, the company said since late March 2020 it has observed several crooks complaining about COVID-19 interfering with the daily activities of their various money mules (people hired to help launder the proceeds of cybercrime).

The same is happening for real world crime also, Jani was telling me about this article on Goa where the local drug dealers are out of job because no tourists are visiting so they all are now selling fish to survive.

Well this is all for now. Will write more later.

– Suramya

July 31, 2020

Interested in Coding using emoji’s? Check out emojicode

Filed under: Computer Software,My Thoughts — Suramya @ 12:12 PM

I am not the most fervent fan of emojis in the world and for the most part I have gone through the last 20+ years with about 3-4 emojis that I use on a regular basis. But I know people who communicate wholly using them and while I am ok with folks using them in personal communications I dislike them immensely in professional communications (except for the occasional smiley face). However not everyone agrees with me and there have been books published in the past using just Emoji’s and now there is a programming language that is written entirely in emoji.

Emojicode, which first appeared as a Github project back in 2016 has been around for a while now and has a fairly strong following in the tech world. I realize that I sound like one of the old men screaming ‘Get off my lawn’ but I really don’t understand why anyone would want to code in a language that uses emoji’s to define text as a serious programming language. As a joke it would be fun to learn but I can’t really imagine coming in to work one day and writing code using Emojocode for a work project.

Here’s an example of the “Hello World” program written using Emojicode.


Hello World using Emojicode

If you want to learn coding in Emojicode, you can check out their impressive documentation or do a Code Academy course on the language. Emojicode is open-source, so you can also contribute to the development via their GitHub repository.

Yes, learning new programming languages is cool, but I don’t think I will be spending the effort to learn Emojicode anytime in the near future.

– Suramya

July 30, 2020

Scientists claim to be able to detect depression in written text using Machine learning

Filed under: Computer Software,My Thoughts — Suramya @ 12:26 PM

Depression is brutal, it can range from feelings of sadness, loss, or anger that interfere with a person’s everyday activities to suicidal tendencies. In the past few months there have been multiple cases of famous people committing suicide because they were depressed and unable to cope with the feelings of isolation and stress brought about by the current pandemic. Unfortunately depression is not an easy thing to diagnose and there isn’t a single test to diagnose it. Doctors can diagnose it based on your symptoms and a psychological evaluation which in most cases includes questions about your:

  • moods
  • appetite
  • sleep pattern
  • activity level
  • thoughts etc

But all of this requires a person to be open about their thoughts and that can be difficult at times due to the stigma associated with mental health issues. In all of the cases I was referring to earlier the common theme from the friends & acquaintances have been about how they wish they had known that xyz was depressed and if they had then maybe they could have helped.

The problem is that people don’t always come out and say that they are depressed and sometime the signals are very faint. So its very interesting to see the various efforts that are underway to identify these symptoms earlier and get the people the help they need faster so that they don’t have to face it alone. As part of this effort scientists at Canada’s University of Alberta have created a machine learning model that uses linguistic clues to indicate signs of depression in text communications like twitter messages and have published a paper on it (Augmenting Semantic Representation of Depressive Language: From Forums to Microblogs) in the ‘European Conference on Machine Learning and Principles and Practice of Knowledge Discovery in Database’.

We discuss and analyze the process of creating word embedding feature representations specifically designed for a learning task when annotated data is scarce, like depressive language detection from Tweets. We start from rich word embedding pre-trained from a general dataset, then enhance it with embedding learned from a domain specific but relatively much smaller dataset. Our strengthened representation portrays better the domain of depression we are interested in as it combines the semantics learned from the specific domain and word coverage from the general language. We present a comparative analyses of our word embedding representations with a simple bag-of-words model, a well known sentiment lexicon, a psycholinguistic lexicon, and a general pre-trained word embedding, based on their efficacy in accurately identifying depressive Tweets. We show that our representations achieve a significantly better F1 score than the others when applied to a high quality dataset.

This is not the first study on the topic and it won’t be the last. The paper is fairly technical and from what I can understand they can identify potential signs of depression based on words used and phrasing. But am not sure how they are taking into account sarcasm and contextual clues. For example without the appropriate context things being said can be taken in many different ways and identifying the correct emotion behind the words can be tricky. When we interact in person or over phone things like body language or verbal cues give us additional context about how a person is feeling, unfortunately that is not the case with text and there is a huge potential for things to be taken out of context or in the wrong way. Another issue is how to differentiate between feelings of sadness and depression as the symptoms might be very similar.

We need human interactions, connections etc to address this issue and not another technology claiming to be a silver bullet as not everything can be solved by AI/ML and the low accuracy level on such solutions can only cause trouble down the line. Imagine such a system being implemented at workplaces, during interviews or on dating sites. If a system flagged you as a depressive then it could cost you your job, or your relationship.

What do you think?

– Suramya

July 27, 2020

Cloaking your Digital Image using Fawkes to thwart unauthorized Deep Learning Models

Filed under: Computer Related,Computer Software,My Thoughts,Techie Stuff — Suramya @ 3:42 PM

Unless you have been living under a rock you have seen or heard about facial recognition technologies that are actively in use in the world. You have the movie/TV version where a still image from a video feed is instantly compared to every image in the database to match a perp, then you have the real world example where there are systems that take all your social media feeds, images of yours posted anywhere as a dataset to train a system that can identify you from a video feed (not as quickly as the TV version but still fast).

So what is the way to prevent this? Unfortunately there isn’t one (or at least there wasn’t a realistic one till recently). Earlier you had to ensure that no image of yours is ever posted online, you are never caught in a security feed or traffic cam anywhere. Which as you can imagine is pretty impossible in today’s connected world. Even if I don’t post a picture of me online, my friends with whom I attended a party might upload a pic with me in the background and tag me. Or you get peer pressured to upload the photos to FB or Twitter etc.

There is not much we can do about state sponsored learning models but there are plenty of other folks running unauthorized setups that consume photos posted publicly without permission to train their AI models. These are the systems targeted by folks from the SAND Lab at University of Chicago who have developed Fawkes1, an algorithm and software tool (running locally on your computer) that gives individuals the ability to limit how their own images can be used to track them.

At a high level, Fawkes takes your personal images, and makes tiny, pixel-level changes to them that are invisible to the human eye, in a process we call image cloaking. You can then use these “cloaked” photos as you normally would, sharing them on social media, sending them to friends, printing them or displaying them on digital devices, the same way you would any other photo. The difference, however, is that if and when someone tries to use these photos to build a facial recognition model, “cloaked” images will teach the model an highly distorted version of what makes you look like you. The cloak effect is not easily detectable, and will not cause errors in model training. However, when someone tries to identify you using an unaltered image of you (e.g. a photo taken in public), and tries to identify you, they will fail.

The research and the tool will be presented at the upcoming USENIX Security Symposium, to be held on August 12 to 14. The software is available for download at the projects GitHub repository and they welcome contributions.

It would be amazing when this tool matures and I can imagine it becoming a default part of operating systems so that all images uploaded get processed by the tool by default reducing the risk of automatic facial recognition. Although I can’t imagine any of the governments/Facebook being too happy about this tool being publicly available. 🙂

Well this is all for now. Will write more later.

Thanks to Schneier on Security for the initial link.

– Suramya

April 23, 2020

Happy World Book day – Support an Author if you can with this list of Author Patreon’s

Filed under: My Thoughts — Suramya @ 11:38 PM

Today is World Book Day and it’s the perfect time to post this. As you know due to Covid-19, the entire world has been turned Topsy-turvey and has impacted people worldwide, this includes book authors as well since they are unable to go out and promote their books so the season’s biggest books are not getting their time in the spotlight. In addition to the lack of limelight a lot of people are also cutting down on their book purchases so that they can focus on surviving this pandemic.

In India because of the lockdown all shops are closed and Amazon can’t deliver books as they are not considered “Essential Items”, since a lot of the authors I like are international ones who are not available in India but are only available via Amazon or Flipkart I can’t get any new books. Yes, I know I can buy e-books but I prefer paper books and don’t want to spend twice on the same book. So I reached out on Twitter to John Scalzy & Mary Robinette Kowal, who is the president of the SFWA (Science Fiction Writers of America) to ask them following question on how I could support Authors during this time:

“Hi @scalzi , @MaryRobinette Is there an official list of patreon’s for various authors? I tried searching but couldn’t find any. if not can we start a list?
Can’t order books right now due to Corona as both local stores & Amazon are closed. But still wanted to support.”

I followed the tweet with links to the Pateron links that I could find and the whole thing just exploded, I got a huge no of comments and views with links to various Patreon’s. Since Twitter is a bad medium to keep something meant for a long term, I am consolidating the list here on my Blog and will keep updating it as and when I find new links for Patreons.

The list is strongly leaning towards Science Fiction & Fantasy since that’s what I mostly read but am open to listing other genres author’s as well. Please note that while I did basic due-deligence on the links I expect you to verify the links as authentic before you start sending them money. Please let me know if there are any changes or issues in the list. I am not responsible if you send money to the wrong person :).

So without further ado here’s the list of Author Patreon’s that I found or were shared with me. Clicking on the name will take you to the author’s Page on Fantastic Fiction and the Pateron link will take you to their Pateron (duh). For the author’s who have no FF page, these are author’s who’s books I have read & bought so I have included them, there were a few that were submitted to me but since I can’t vouch for them if they are not on FF I didn’t add them to the list below.

So some quick Q&A before I close the post:

Q. Are you getting a commission on this from referels?
A. No. This is just so that I can have a central list where all author Paterons are listed and folks can use this to support their favorite authors.

Q. Aren’t there other people in the world and in India who are going hungry like migrant workers who can better use the money?
A. Yes, there are too many people living on the edge and barely surviving. Unfortunately I can’t do something for all of them, though I have donated to various organizations that are supporting them. This is something for authors who have kept me sane and centered through my life.

Q. Will you be updating the list? Can I submit additions?
A. Yes & Yes. You can either tweet the additions to me, post them as comments to the blog post or email them to me.

Well this is all for now. Will post more later.

– Suramya

March 22, 2020

Covid-19: Some thoughts and comments

Filed under: My Thoughts,Uncategorized — Suramya @ 6:16 PM

These past few months have been a bit scary. Since Jan we have been watching Corona virus cases spike in China, get ignored and then massive effort to contain the virus. The same was done in Singapore, South Korea etc. India was relatively untouched with minimal cases in the first few months of the disease. Then we had a spike due to people returning from US/Europe etc and infecting others.

I am surprisingly impressed with how Indian Government has reacted to this issue, with both state and national governments taking strong steps to contain. I was especially surprised by how quickly government of Karnataka reacted because honestly I feel that they are mostly useless. They quickly shutdown all schools when the cases in KA were still at 4, and once we had the first death due to the virus in the state they immediately stopped all public gatherings as well as malls, pubs etc.

Now we are going to a total lockdown on Bangalore and some of the other infected areas. Section 144 is being imposed in parts of the country where idiots are refusing to adhere to the social distancing. To emphasise, social distancing the main method to reduce the speed of the spread of the virus. Here’s what the government is doing to help: (this is for the idiots who keep asking what the government is doing. More on this later in the post):

Karnataka to close borders, postpone SSLC exams, and elections

The Karnataka government will close all borders with its neighbouring states to tackle theCOVID-19pandemic. An executive order to that effect detailing the duration of the lockdown is expected soon.

Coronavirus: Mizoram announces statewide shutdown till March 29

The Mizoram government on Saturday ordered a “partial lockdown” across all districts of the state till March 29 in the wake of the coronavirus pandemic, according to a notification.

Punjab orders lockdown:

Ordered statewide lock down till 31st March to check spread of COVID-19 All essential Govt services will continue & shops selling essential items such as milk, food items, medicines, etc will be open. All DCs & SSPs have been directed to implement the restrictions immediately. – Amarinder Singh

Coronavirus: Indian Railways suspends all passenger services from March 22 midnight to March 31 midnight

In an unprecedented move, the railways on Sunday announced suspension of all its passenger services from March 22 midnight to March 31 midnight and said only goods trains will run during the said period.

Govt announces lockdown in 75 districts

Government announces lockdown in 75 districts that have reported COVID-19 cases and casualties. Only essential services will operate in these 75 districts. Restrictions on non-essential passenger transport, including inter-state bus services remains till March 31. The decision has been taken after a meeting Cabinet Secretary held with Chief Secretaries of States and principal Secretary to Prime Minister.

Section 144 in Bengaluru from 9 pm to 12 am

Section 144 imposed from 9 pm to 12 am (midnight) in commissionerate limits to ensure people do not come out of their home once the Janta Curfew ends: Bhaskar Rao, Commissioner of police, Bangalore city. (ANI)

Section 144 imposed in Delhi

In wake of the coronavirus outbreak, Section 144 of CrPC to be imposed in Delhi with effect from 9 pm on March 22 to 12 midnight of March 31. (ANI)

This is just an small list of the actions that are being taken to stop the spread. Yes, there were mistakes made and are being made but the focus is to resolve them quickly and move forward. For example a decision was taken to allow the Ayodhya celebration to happen but then the permission was revoked after a large no of people protested and the medical community advised against it as well.

On Friday, PM Modi adressed the nation and asked for a self curfew to be done on Sunday all day to help curb the spread. This was a voluntary curfew to enforce social distancing. No where did he say that the virus is going to be dead in 12-14 hours and then we can go back to normal on Monday. He asked for everyone to coorporate in social distancing for the next few weeks. You can read the complete text of his address here. Below is an extract from the address:

Hence, it is imperative to keep two key factors in mind in order to combat this global pandemic – Determination and Patience. Today, all 130 crore fellow citizens of Indians will have to further strengthen our resolve to overcome this global crisis, fulfilling all our duties as citizens, and abiding by the directions given by the Central and State governments. Today, we must all resolve to not get infected ourselves, and prevent others as well from getting infected.

Friends, during such a pandemic, only one mantra can take us through – ‘Hum Swasth, toh Jag Swasth’, that is the world will be healthy, if we stay healthy. In a situation like this, where there is no known cure for the disease, it is imperative that we stay healthy. Patience is an essential virtue to avoid this disease, and keep oneself healthy. And how does one practice patience? By staying away from crowds and gatherings, avoiding leaving your homes. This is called ‘Social Distancing’ nowadays, and is critical in these times of the global corona pandemic.

Our determination and patience will play a crucial role in containing the impact of this global pandemic. It is wrong if you believe that you are okay and nothing can happen to you, and you can continue roaming around in markets and streets as usual and remain unaffected. By doing this, you will not only be unjust to yourself but also to your family.

Keeping this is mind, I appeal to you all that for the next few weeks, step-out of your homes only when absolutely necessary. As far as possible, try and do your work, whether related to business or job, from home.

While it is essential that those who are in government services, healthcare services, people’s representatives, media personnel remain active. Everybody else must however, isolate themselves from the rest of society.

Global research and experts have been talking non-stop that the main way to stop the spread of Convid-19 is to practive social distancing. That’s what the goverment is asking us to do. Plus this is not all there are multiple other steps being taken to reduce the impact and economic packages to help the poor and impacted are in progress. Yes, we could move faster on this but some things take time.

In addition Modi asked for one more item in his speech.

Friends, in the midst of all these efforts of the people’s curfew on 22nd March, I would also like to seek your support on one more matter on that day. For the past 2 months, lakhs of our people have been working day and night in our Hospitals and Airports.

From doctors to nurses, hospital staff, sanitation workers, airlines employees, government staff, police personnel, media people, people associated with train-bus-auto rickshaw services, and home delivery agents; all have been selflessly serving others, without caring about themselves.

In the current circumstances, these services cannot be considered to be ordinary. Today, these people run the risk of getting infected themselves. Yet, they continue to fulfil their duties, serving others. As defenders of the nation, they stand firmly between us and the corona pandemic. The nation is grateful to them all.

I wish that on Sunday, 22nd March, we express our gratitude to all such people. On Sunday at exactly 5 pm, we all stand at the doors, balconies, windows of our homes, and give them all a 5-minute standing ovation. We clap our hands, beat our plates, ring our bells to boost their morale, salute their service.

To inform people about this, I request local authorities across the country to ring a siren at 5 pm on 22nd March.

We must with full sincerity, express our feelings towards all such fellow citizens who have lived by our value-system of ‘Seva Parmo Dharma’, that is Service being the highest Duty.

Note that he did not claim that this will kill Corona virus due to astrology, veda’s, sound therapy or whatever. This is just to show our appreciation for the people putting their life at risk for us to be able to continue with life. Remember the meal you ordered on Swiggy that was delivered by a person? The sweepers who are cleaning the floor or buildings? The train/bus drivers taking people around? They are risking infection so that we can continue. This is a tribute to them. Why is it ok to celebrate our cricket team’s win in a stupid game by yelling & screaming and being out on the street but suddenly its too much if you are asked to applaud for people risking their lives and the lives of their loved ones to serve you.

Worldwide people are doing this, a 30 second search gave me: Israel, Spain & Italy (who are doing it daily BTW), Germany , UK and so many more.

People need hope when things are grim. This is giving them hope. Remember Pandora’s box? The last thing remaining in the box after all the evils escaped was hope to give us the strength to battle evil & tough times. Jews sang during the War, soldiers sing at the front, this is not because it magically solves the problem but because it gives us the strength to say: I can do this. We will get through this together.

Now, lets look at what the so called ‘intellectuals’ & some of the educated people are doing shall we? Anti-CAA protests are continuing because apparently if you don’t support CAA you are immune to Coronavirus. People are absconding from home to roam the city and attend functions while they are supposed to be in quarantine. 4 morons took a train from Mumbai after being told to isolate and were only caught because they were stamped with a quarantine order and someone on the train noticed it and called the cops. Apparently we have a lot of alcoholics in the country because people are still going to Bars at night because it’s too much of a bother to stay home. This behavior is mostly in the educated class and the so called intellectuals. My maid and driver are talking about self-isolation and how they are working to ensure the spread is contained. Our building guards are enforcing hand-wash discipline for all visitors but we the educated class can’t be bothered because its too much effort. The virus doesn’t care about how much money you have and what position you are at. Do you know who I am? will not work on the virus. Washing your hands and self-isolation will.

All the morons who are going out when known COVID-19 positive or asked to self isolate should be charged with murder if any death that can be traced back to them *knowingly* being out in public after being told not to. If no death then they should be jailed for public endangerment. There is a EU country that is charging such folks with murder and I think we should do the same.

Please listen to medical professionals, reputed sources (this doesn’t include your whatsapp forwards from your 2nd cousin’s friend who heard it from his friend). Follow basic common sense rules and you will be ok.

Well this is all for now. Will write more later. Stay safe you all, and above all stay at home.

– Suramya

March 4, 2020

Seti@home project to stop distributing new work to clients after 21 years

Filed under: Computer Software,News/Articles — Suramya @ 1:44 PM

Seti@home has a fond place in my heart. It has been run by the Berkeley SETI Research Center since 1999, and I think I installed it on my machine sometime around Dec 1999 or early 2000 after hearing about it from one of the News websites (possibly Slashdot). Once I had it running on my system I was pushing to get it installed on all the computers in the University computer lab as they were running 24/7 and I saw that as a wasted opportunity for furthering search for ET. I ran it constantly on my computers till about 2009 post which I switched to running Folding@home which is more focused on Science / DNA sequencing / Medical research. Seti was one of the first Distributed computing systems that I know of and the amount of data processed by computers under its umbrella is staggering.

On March 31, the project will stop sending out new work units to users and the project will instead start focusing on analyzing all the blips identified by volunteers’ machines which could be potential evidence of aliens with an eye on publishing a research paper. Once this is completed they might start pushing out work packages again but that will be a while before it happens.

“It’s a lot of work for us to manage the distributed processing of data. We need to focus on completing the back-end analysis of the results we already have, and writing this up in a scientific journal paper,” their news announcement stated.

Looking forward to reading the research paper and conclusions generated by the Seti@home program.

Source: SETI@home Search for Alien Life Project Shuts Down After 21 Years

– Suramya

March 2, 2020

Another magical AI to detect “Inappropriate photos” and block kids from taking them

Filed under: Computer Software,My Thoughts,News/Articles — Suramya @ 11:50 AM

In today’s iteration of people who don’t want to make the effort of raising their kids and explaining the difference between right & wrong and why something might be a bad idea we have a new “magical” AI that will automatically detect when kids are making a bad choice and stop them. I mean why should a parent make an effort to talk to their kids and help them understand what repercussions of a given choice could be wrong when you have AI to make the effort for them? This new AI is being pitched to parents and has an AI-powered “Smartphone Protection” feature that prevents users from shooting or saving “inappropriate” photos (read: naked pictures).

The official Tone Mobile press release hails the TONE e20 as the world’s first phone with an AI that “regulates inappropriate images” through an AI built into the so-called TONE Camera… If the AI recognizes that the subject of a photo is “inappropriate,” the camera will lock up; and if you somehow manage to snap a photo before the AI kicks in, the phone won’t let you save or share it.

Additionally, a feature called “TONE Family” can be set to send an alert to parents whenever an inappropriate image is detected. According to SoraNews24, this alert will contain location data and a pixelated thumbnail of the photo in question.

I give it about 24 hours from when the phone is released till folks figure out a way around it.

The other issue I have with this system is how its going to classify the pics. The article doesn’t go into technical details of how the AI works and if the classification is done locally or on the cloud. If its on the cloud then every pic taken by that phone is being uploaded to a remote server owned by a 3rd party. This is a massive risk and any breach of that server is going to have a lasting and significant impact. Trust me when I say that this server would be a target of all Black Hat hackers as soon as it goes online.

I am not going to go into whether taking nude pics is a good idea or not. Its upto the people involved to take that decision, I am not responsible for what you do with your phone. If you have to take naughty pics just ensure you follow basic rules and don’t share it with anyone you don’t trust 100%.

In summary, Dear parents: Instead of offloading your responsibilities to AI try having a frank and open conversation with your kids about why certain things might be a bad idea. It will give you better results than this snakeoil.

Source: Slashdot.org

– Suramya

January 14, 2020

Paris Musées releases Images of 100,000 Artworks to the Public for free

Filed under: Interesting Sites — Suramya @ 1:10 PM

Remember when the Art Institute of Chicago released 52,438 HD art images into the public domain? Paris Musees, a collection of 14 Paris museums, collectively said, “Tiens mon vin” (Hold my wine) and released 100,000 digital reproductions of artworks in the city’s museums as Open Access — free of charge and without restrictions — via its Collections portal. Paris Musées is a public entity that oversees the 14 municipal museums of Paris, including the Musée d’Art Moderne de la Ville de Paris, Petit Palais, and the Catacombs.

“Making this data available guarantees that our digital files can be freely accessed and reused by anyone or everyone, without any technical, legal or financial restraints, whether for commercial use or not,” reads a press release shared by Paris Musées.

At this stage, images available are of 2D artworks, such as paintings or photographs, that belong in the public sphere under a CC0 (Creative Commons Zero) license, which allows creators and owners of copyrighted or database-protected content to place those works in or as close as possible to the public domain. (Works still in copyright will be available as low definition files, so users can still get a feel for the museums’ collections online.)

It’s nice to see more and more organizations making their work available online for free under CC licenses.

Thanks to Metafilter for the initial link.

– Suramya

January 6, 2020

Using Math to figure out why One Knot Better Than Another

Filed under: Interesting Sites,News/Articles — Suramya @ 3:12 PM

Have you ever wondered why certain knots are more stable than others? Or have you stressed about which knot is the most suitable one to use in your specific usecase and had a disagreement with someone about the best option? If so then fear-not MIT researchers have developed a mathematical model to predict a knot’s stability and now you can argue for your choice with conviction that math supports your choice. From the paper’s abstract:

Knots play a fundamental role in the dynamics of biological and physical systems, from DNA to turbulent plasmas, as well as in climbing, weaving, sailing, and surgery. Despite having been studied for centuries, the subtle interplay between topology and mechanics in elastic knots remains poorly understood. Here, we combined optomechanical experiments with theory and simulations to analyze knotted fibers that change their color under mechanical deformations. Exploiting an analogy with long-range ferromagnetic spin systems, we identified simple topological counting rules to predict the relative mechanical stability of knots and tangles, in agreement with simulations and experiments for commonly used climbing and sailing bends. Our results highlight the importance of twist and writhe in unknotting processes, providing guidance for the control of systems with complex entanglements.

To give some more context, below is an extract from a SciTech Daily Article covering the research. To be honest I had to read the article a few times to understand what they were talking about but it sounded interesting. Not sure how useful it is but is definitely interesting. 🙂

In comparing the diagrams of knots of various strengths, the researchers were able to identify general “counting rules,” or characteristics that determine a knot’s stability. Basically, a knot is stronger if it has more strand crossings, as well as more “twist fluctuations” — changes in the direction of rotation from one strand segment to another.

For instance, if a fiber segment is rotated to the left at one crossing and rotated to the right at a neighboring crossing as a knot is pulled tight, this creates a twist fluctuation and thus opposing friction, which adds stability to a knot. If, however, the segment is rotated in the same direction at two neighboring crossing, there is no twist fluctuation, and the strand is more likely to rotate and slip, producing a weaker knot.

They also found that a knot can be made stronger if it has more “circulations,” which they define as a region in a knot where two parallel strands loop against each other in opposite directions, like a circular flow.

By taking into account these simple counting rules, the team was able to explain why a reef knot, for instance, is stronger than a granny knot. While the two are almost identical, the reef knot has a higher number of twist fluctuations, making it a more stable configuration. Likewise, the zeppelin knot, because of its slightly higher circulations and twist fluctuations, is stronger, though possibly harder to untie, than the Alpine butterfly — a knot that is commonly used in climbing.

The formal paper is published at: Science Mag.
Thanks to Slashdot for the initial link.

– Suramya

Older Posts »

Powered by WordPress