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Arnab Gupta's personal website. Ph.D. in Engineering Mechanics. Photographer, blogger, tech enthusiast.

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☞ FIFA updates its ethics code... to fight defamation, not corruption

Permalink - Posted on 2018-08-16 04:00

From the AP:

FIFA has officially eradicated corruption. All it took was pressing the delete key.

Soccer officials and players who bother checking out the new code of ethics governing their conduct will find the word “corruption” missing. They also will discover how to avoid being banned for paying and receiving bribes.

It seems that the lesson that FIFA took from their massive corruption scandal is that they need to run a tighter ship in terms of information about the corruption getting out.

Related, they have also previously addressed racism in the sport by disbanding its anti-racism taskforce, declaring that it had “completely” fulfilled its mission. “Completely”; meanwhile, task force member Osasu Obayiuwana had this to say:

“I wish I could say that I am shocked by the decision, but unfortunately I am not. The problem of racism in football remains a burning, very serious and topical one, which need continuous attention."

What would you bet that the next FIFA scandal won’t be too far away, however much they declare defamation of the body to be a punishable offense?


☞ The ugly scandal that cancelled the Nobel prize in literature

Permalink - Posted on 2018-07-18 04:00

From the Guardian:

In the eyes of its members, there is no more important cultural institution in the world than the Swedish Academy. The members, who call themselves The Eighteen (always in capitals), are elected for life by their peers, and meet for a ritual dinner every Thursday evening at a restaurant they own in the heart of the old town in Stockholm. And once a year, at a ceremony brilliant with jewels and formality, the permanent secretary of the academy hands out the Nobel prize in literature and all the world applauds.

But this year there will be no prize and no ceremony. In November 2017, it was revealed in the Swedish press that the husband of one of the academy members had been accused of serial sexual abuse, in assaults alleged to have taken place over more than 20 years. Jean-Claude Arnault, a French photographer and cultural entrepreneur, is married to the poet and academician Katarina Frostenson. In addition to assault accusations against him, the pair are accused of misusing academy funding. Arnault has denied all accusations, and Frostenson has refused to comment.

The academy is paralysed by the scandal, which was followed by a slew of resignations and expulsions. Six of The Eighteen have withdrawn from any part in its deliberations; another two were compelled to do so. The statutes say that 12 members must be present to elect any new ones, so with only 10, no important decisions can be taken and no new members elected.

What a mess this is. I’m tempted to say “you can’t make this stuff up”; would that be too ironical?


☞ Disposable America — A history of modern capitalism from the perspective of the straw. Seriously.

Permalink - Posted on 2018-07-11 04:00

By Alexis Madrigal for The Atlantic:

The invention of American industrialism, the creation of urban life, changing gender relations, public-health reform, suburbia and its hamburger-loving teens, better living through plastics, and the financialization of the economy: The straw was there for all these things—rolled out of extrusion machines, dispensed, pushed through lids, bent, dropped into the abyss.

You can learn a lot about this country, and the dilemmas of contemporary capitalism, by taking a straw-eyed view.

This is a very well researched article on the humble drinking straw, and its correlation with the evolving American societal outlook. The pervasiveness of the drinking straw in this society probably makes this a pretty good correlation to make.

Go read, this is quite an interesting, albeit long, read. (I did not know, for example, that the original straw was made from actual straw.)


☞ New free street library in Kolkata!

Permalink - Posted on 2018-07-02 04:00

The Indian Express reports:

If one gets down at Netaji Bhavan metro station and walks towards Rammohan Dutta road straight to Northern park one would stumble upon a rather curious sight. College-goers can be seen crowding the area and a familiar smell of books envelops it. Several books are exhibited in bookshelves on the footpath and it almost seems like a bookstore at first glance. This, however, is no bookstore, instead, it is an expansive library that houses books by authors ranging from popular Bengali comic books to Sidney Sheldon. The name of the place is Street Library.

This is such a lovely concept. Anyone who wants to read can pick up a book and return it once they are finished. People who have books that they don’t plan on keeping can donate and improve the collection. People with organization skills and some spare time can chip in and organize the collection every once in a while.

This is an excellent program that encourages reading, sharing and selflessness. It also depends on a community working together to keep a good thing going. I wish this all the best, and really hope that there is enough community interest and investment to overcome the occasional miscreant. Although Kolkata is home to the National Library of India, and hosts several other libraries, they are either not free or not easily accessible for many people. Street libraries are an excellent idea for people short on time and energy but an interest to read.

If you’re in Kolkata and have some books to spare, perhaps you can consider donating to this? Or better yet, perhaps you can see if something similar can be organized in your part of the city?


☞ Indian banks contemplate 'face reading' to spot doubtful loan seekers

Permalink - Posted on 2018-06-29 04:00

From the Times of India:

Private banks in the western coastal state [Gujarat] have approached the Gujarat Forensics Science University to prepare a facial micro-expressions manual, to train its employees in recognising doubtful high net-worth customers like fugitive liquor baron Vijay Mallya demanding loans.

This is straight out of the American TV series Lie to Me (IMDB Link):

In the show, Dr. Cal Lightman (Tim Roth) and his colleagues in The Lightman Group accept assignments from third parties (commonly local and federal law enforcement), and assist in investigations, reaching the truth through applied psychology: interpreting microexpressions, through the Facial Action Coding System, and body language.

Have the Indian bankers in question seriously been watching too much TV reruns? In the show, the protagonists use micro expressions to evaluate suspects and their testimony to solve crimes. That’s slightly different from the real world case of deciding whether to give out large loans, no? (For context, India has had a slew of recent large loan frauds.)

I am completely bewildered by this. If there have been some large loan frauds, shouldn’t the most important step be a complete overhaul and re-evaluation of how credit-worthiness of prospective clients is determined? In a financial sense? In a risk assessment and cost-benefit analysis sense? In an available collateral sense? Especially given that investigations have been called for on bank employees, it has been alleged that a bank CEO “failed to initiate steps” to prevent the fraud after there were red-flags, and bank officials have been charged?

Do the bankers really believe that there is nothing to improve on their financial evaluations side and in their employee honesty side? Or is this a case of putting their head in the sand and going ‘la-la-la’? Are the bankers too entrenched in their current practices and workflows, don’t want to go through the trouble — and the expense — of actually re-evaluating their own businesses, and are looking for guises to exculpate themselves?

I mean, seriously, if the banks want to go for next generation methods, artificial intelligence and machine learning would be an actual avenue to explore. Examples to be found here and here. There are even courses and available computer code(here and here) to get people started!

Come now, bankers in question: get real and find real solutions to your real problems, and stop with the hand waving TV-show inspirations.


☞ Indian Railways decides to enforce baggage limits

Permalink - Posted on 2018-06-06 04:00

The Times of India reports:

As a result of numerous complaints regarding excess baggage being towed into train compartments, the Indian Railways has decided to strictly enforce its over-three-decades-old baggage allowance rules, which will see passengers paying up to six times the stipulated amount as penalty, if caught travelling with overweight luggage, an official said today.

I never even knew that these baggage rules existed. All these years, I’ve simply assumed that there were no formal baggage limits; that space constraints and being reasonable to fellow passengers is all that stops people from carrying waaay too much stuff with them on to trains. Unfortunately, people often do carry too much stuff with them, and to the level of straining and breaking limits of reason.

Which is why the rule enforcement itself, to me, is entirely justified. Even in the little travel that I have done via Indian Railways in the recent past, people carrying way too much luggage, both in quantity and physical size, is way too common for comfort.

The important question, though, is how much luggage is allowed? After all, the railways is used in a vast majority by people for whom expense is a major factor.

According to the prescribed norms, a sleeper class and a second class passenger can carry luggage weighing 40 kg and 35 kg respectively without paying any extra money and a maximum of 80 kg and 70 kg respectively by paying for the excess luggage at the parcel office. The excess luggage would have to be put in the luggage van.

[…]

For example, if a passenger is travelling 500 km with luggage weighing 80 kg in the sleeper class, he can book his excess baggage of 40 kg for Rs 109 in the luggage van.

[…]

Similarly, an AC first class passenger can carry 70 kg of luggage for free and a maximum of 150 kg, after paying a fee for the excess 80 kg.

An AC two-tier passenger can carry 50 kg of luggage for free and a maximum of 100 kg by paying a fee for the excess 50 kg.

Only 35-40kg for the second class passenger? That seems a little on the lower side. Barely a couple of suitcases, perhaps? In our international travel to and from the USA we’re allowed 46kg in two checked in suitcases, along with additional cabin baggage; surely a railway compartment should be able to accommodate more per passenger? The limits for the AC classes seem a little more reasonable, but still low considering that fewer passengers occupy the same compartment area.

The cost for extra baggage doesn’t seem too bad either. About Rs. 100 for essentially doubling the baggage allowance is hopefully okay, considering prices of other commodities, although I hope the baggage charges increase with the class of tickets. The cheapest tickets should really also have the cheapest excess baggage charges, considering the budget conscious traveler.

I’m most concerned, though, with two things. One, the excess luggage is to be placed in a separate luggage van. (Come to think of it, I’ve always known these luggage vans exist on trains. I always assumed they were for freight or oversized luggage. Huh.) I’m guessing the luggage van is perfectly safe with no fear of theft, but I’m also certain many, many passengers will take a long time to be comfortable with the idea of their bags not being right next to them. (Although, side benefit: if the bags aren’t just lying around in the compartment, they’re safer from theft.)

Two, they say they will “enforce” the law by random checks. This is bad, especially in India, where: (a) this situation is ripe with bribing opportunities, and (b) random checking introduces the concept of fairness between travelers who got caught and who didn’t. I really hope they figure out a more robust way of executing this.

In concept, the baggage allowance idea seems reasonable, but I hope they do a good job of the current idea, and I really hope they revisit the current ideas and update them based on feedback and usage data. The Indian Railways is a lifeline in India, and things like this can have a major effect either way.


☞ How the smallest programming bugs can be catastrophic

Permalink - Posted on 2017-12-15 05:00

From way back in 1996:

It took the European Space Agency 10 years and $7 billion to produce Ariane 5, a giant rocket capable of hurling a pair of three-ton satellites into orbit with each launch and intended to give Europe overwhelming supremacy in the commercial space business.

All it took to explode that rocket less than a minute into its maiden voyage last June, scattering fiery rubble across the mangrove swamps of French Guiana, was a small computer program trying to stuff a 64-bit number into a 16-bit space.

One bug, one crash. Of all the careless lines of code recorded in the annals of computer science, this one may stand as the most devastatingly efficient.

More links here, and the report of the inquiry into the incident is archived here.

A fascinating, and from a programmer’s perspective chilling, read. This is the stuff of nightmares — an apparently innocuous line of code causing an exception that leads to disaster!


Adios Cassini

Permalink - Posted on 2017-12-12 05:00

A couple of months ago, 15 September to be precise, marked the end of an era in the human exploration of our solar system. The Cassini spacecraft was programmed to crash into Saturn’s upper atmosphere and burn up, thus ending an almost two-decade journey and exploration of Saturn and its moons. I was in middle school when this mission launched in 1997, and at that point, even reaching Saturn in 2004 seemed eons away. Twenty years later, perhaps it’s time to look back at some of the amazing insights we’ve gained.

Cassini is actually a shortened name for the Cassini-Huygens mission, and comprises the main spacecraft — Cassini — designed to travel as a satellite in the Saturn planetary system, and a small lander — Huygens — designed to actually land on Titan, Saturn’s largest moon.

Giovanni Cassini was an Italian mathematician and astronomer, and discovered four of Saturn’s moons — Iapetus, Rhea, Tethys and Dione. The Cassini spacecraft was the first to observe all four of these moons. Christiaan Huygens was, of course, a famous Dutch astronomer and scientist, and discovered — but of course — Titan, then the first known moon of Saturn. (He also invented the pendulum clock, was mentor to Gottfried Leibniz, studied optics and the wave nature of light, and derived the modern formula for centripetal force.)

Saturn by Cassini

Saturn by Cassini (via Wikipedia).

Of the many discoveries made by Cassini, I’ll focus on just two stories: those of Saturn’s largest moon Titan, and Saturn’s hexagon. Both of these fascinate me to no end, and I think reflect the best of Cassini’s contributions.

Saturn’s Polar Hexagon

Jupiter is famous for its Great Red Spot; Saturn has its own atmospheric phenomenon that’s equally fascinating. Saturn’s Hexagon was first discovered by the Voyager missions, but now Cassini has had the chance to see it from up close.

Technically, the Hexagon is a persisting cloud pattern formed by jet streams around Saturn’s north pole, but its sheer size and perfect symmetry make it unique. Each side of the hexagon is about 13800km long (to compare, Earth’s diameter is about 12700km), and its winds travel at around 300km/h. It’s been there since the Voyager missions in the 1980s, so we know its long-lived.

Saturn - North polar hexagon and vortex as well as rings (April 2, 2014)

Saturn - North polar hexagon and vortex as well as rings (April 2, 2014) (via Wikipedia).

On Earth, our jet streams are forced to bend and move in response to Earth’s surface features such as mountains. Saturn is much larger than Earth (Saturn diameter is about 116000km) but has a rocky core that’s similar in size to Earth, and so its jet streams have no such problems, and can keep flowing in their own orderly and symmetrical fashion.

The hexagon is essentially a quirk of fluid mechanics. Here on Earth, scientists have been able to create (here, and here) such regular shapes by rotating a circular tank of liquid at different speeds at its center and outer edge. Due to the difference in speeds, a turbulent region is created where such regular shapes can be observed. The regular shape is not always a hexagon (shapes with three to eight sides, i.e. from a triangle to an octagon, are produced) but a hexagon is the most commonly occurring. However, the phenomenon only occurs when the speed differential and fluid properties fall under certain small margins, and therefore the hexagon phenomenon is not observed everywhere where its possible (such as Jupiter, or even the south pole of Saturn).

At the center of the Hexagon, right at the north pole, is a humongous storm, with a definite and easily observed eye wall. The south pole has such a storm as well, although it doesn’t display a Hexagon. In each case, the eye of the storm is about 50 times wider than a hurricane would be on Earth.

As much as the Hexagon is an atmospheric and scientific phenomenon, explained and replicated under lab conditions, it’s one of our solar system’s most beautiful sights, and something I’ll keep looking for in photos of Saturn, now that I know it’s there.

False color image of storms at Saturn's north pole

False color image of storms at Saturn's north pole (via JPL/NASA).

Titan

Titan is Saturn’s largest moon, and of special interest to us: Titan is the only known moon with an atmosphere, and the only one other than Earth whose atmosphere is majority nitrogen. Moreover, its atmosphere is denser and more massive than ours, and is opaque at many wavelengths of light. This means that, like Venus, we had no idea of what the surface of Titan looks like until we had a probe that could land on the surface of Titan. Thanks to Cassini and Huygens, we know a lot more today about Titan than we did in 2004.

Titan, we know now, has an active weather system, including wind and liquid rain, just like on Earth. Of course, the liquid that rains is different from Earth: it rains liquid methane on Titan. Nevertheless, its nitrogen atmosphere and presence of liquids means that Titan’s methane cycle is analogous to Earth’s water cycle. Titan’s upper atmosphere is also affected by ultraviolet light from the Sun, whereby atmospheric methane is broken down and reconstituted into a diverse mix of complex hydrocarbons.

We’re not done yet with the comparisons with Earth! Titan has lakes and oceans, comprised of methane, ethane, and dissolved nitrogen; this makes Titan only the second object in the Solar System (after Earth) to have stable liquids present at ambient temperatures. It most likely also has volcanoes, and is affected by tidal effects from Saturn’s massive gravity. Titan’s surface, specifically where Huygens landed, looks uncannily like Earth, with ‘globules’ about 10-15cm in size, made probably of water ice.

Huygens' view of Titan's surface

Huygens' view of Titan's surface (via Wikipedia).

It’s almost as if Titan is an analogue of Earth— only much colder. In fact, in very specific ways it’s not even colder by much thanks to Titan’s greenhouse effect and tidal heating from Saturn. Cassini has performed numerous gravity measurements of Titan, which reveal that there is a hidden, internal, ocean of liquid water and ammonia beneath Titan’s surface.

So, to summarize, Titan has: an active weather system, large quantities of complex hydrocarbons (Titan is much, much richer in hydrocarbons than Earth), tidal effects from Saturn, and interaction of its atmospheric methane with ultraviolet radiation from the Sun, and even and underground ocean of liquid water and ammonia. A question is begging to be asked at this point: what are the chances of life (past, present or future) on Titan?

Scientists think Titan definitely has the potential to contain habitable environments. Similar to Earth in its infancy, Titan today has the pieces needed for new life to possibly form. Whether it already has, or the extent of future possibility, can only be understood with even better exploration. Indeed, quite a few ideas for future missions dedicated to Titan have been proposed, but none have really gotten off the ground (pun intended) yet.

The most promising of them all is a design to send a submarine to Titan that can explore the seas of Titan, but even this idea is in relatively early stages.

So Much More…

I’ve really just scratched the surface here of how much the Cassini mission gleaned from the Saturn system. There’s so much more: Saturn’s rings and their composition; the moon Enceladus and its jets of icy particles and subsurface ocean of salty water; the moon Iapetus and its equatorial ridge; the moon Mimas and its crater that gives it the Death Star look… trust me, if you don’t take an interest yet, you will once you start reading.

The Cassini-Huygens mission really gave us glimpses into a planetary system that provides great opportunities for scientific discovery, amazing new and diverse worlds, and even — dare we dream? — possibilities of places that can harbor life.

It’s time to say adios to Cassini, but of course, we humans have a long way to go before we can say we know our own solar system.

Saturn's moon Mimas, with the crater Herschel visible prominently

Saturn's moon Mimas, with the crater Herschel visible prominently (via Wikipedia).

(This piece first appeared in the 2017 edition of Sharod Sombhar, an annual magazine from the Bengali Students’ Association at Virginia Tech.)


Of India's high-speed rail ambitions, and lazy Indian journalism

Permalink - Posted on 2017-09-18 04:00

India’s plans about building a high speed rail route connecting Mumbai and Ahmedabad have been in the news lately. The project is funded by a low-interest loan from Japan (covering 80% of the cost of the project), and will make use of Japanese high-speed rail technology used for the Shinkansen.

Of course, along with the project being in the news, it is also subject to critique in news articles, as any expensive government venture is bound to (and should!) be. In many of the articles, though, I found one common piece of information mentioned over and over:

According to a study conducted by IIM Ahmedabad, Ahmedabad-Mumbai bullet train will need to make 100 trips daily and carry 88,000-118,000 passengers per day to be financially viable. This figure could well be way above the total number of passengers travelling between the two cities on any given day.

In fact, searching the internet with the name of the article in question (Dedicated High Speed Railway (HSR) Networks in India: Issues in Development) provides a result that looks like this:

Google Search Result

Google Search Result. (Source)

They all mention the same report, and all mention the exact same language about “requiring 100 trips a day”. None, however, actually provide links for the curious reader, nor provide any context or analysis. Well, I was curious, so I tried to find and read the actual report.

This is the the report I found online. It’s co-authored by Prof. G. Raghuram as mentioned in all the newspaper reports, and calls itself “an abridged version of an IIMA working paper with the same title.” Unfortunately, the IIMA working paper link is broken, and the Wayback Machine doesn’t have it archived either. (P.S.: Between the time that I found and read the report, and I finished writing this piece, the webpage hosting the report seems to have gone dead. No matter, the Wayback Machine has it cached. Go read!)

Anyhow, the report is a great read. After reading it, though, I was reminded of how poor India’s average journalism has come to be. What every news article printed is actually in the report being cited, and yet — and yet! — what they printed is a complete misrepresentation of the entire point and view of the report.

Let’s start with the conclusions of the report. The following are direct quotes from the Conclusions section:

  • Given that India is a developing country, the primary concern is whether the funds for such a project could be better utilised in other domains, including in upgrading conventional rail. However, the Japanese funding to the tune of 80% of the project cost may not be available for other uses.
  • there are many positive benefits and externalities of the HSR which would be useful in India’s overall aspirational development. These externalities include technology percolation into other domains, economic development, game-changing sense of connectivity, and national pride due to cutting-edge infrastructure. In such a context, it is a good idea to begin and learn.
  • The Mumbai-Ahmedabad route is a good choice for the first route, since it connects India’s first and seventh most populous cities, with significant economic development in the 500 km corridor between them.
  • The low cost Japanese financing has been a great catalyst. Though it is a tied funding with significant mandatory procurement from Japan, it cannot do much harm since Japan is at the cutting edge of HSR technology with over 50 years of experience.

Evidently, the overarching view of the article is not that “100 trips will be needed per day…”. Let’s talk about that part next, then. Here’s the crucial paragraph from the article:

Assuming that 20% (apart from the 80% Japanese funding at concessional rates) of the total cost of the Mumbai-Ahmedabad route would be funded by the Government of India (GoI) with an expected 8% annual return during the operational phase, the estimated daily financing costs for the route would be INR 106 million from when the repayment of the loan kicks in. We take this to be the 16th year (till when the Japanese loan has a moratorium), by when the ramp-up of traffic should have occurred. The project cost includes the ‘interest during construction’ for seven years. Over the remaining eight ramp-up years, we assume that there would be enough operating surplus to cover the interest payments. Subsequent to this, the GoI portion is treated as an equity with only interest due, but no principal repayment. Taking an average fare of INR 5.00 per km for the route with intermediate stops and for a scenario of 0.4 operating ratio, we arrive at a daily required ridership of 118,000 passengers (which translates to 43 million passengers annually). At an average of 1000 passengers per train, over 100 services per day (50 per direction) would be required.

What this means is that if the financing for the rail route is to be paid from the revenue from the rail route only, then about 118000 passengers, at an average of 1000 per train, over 100 services daily, would need to travel on the route. The newspaper articles only mention the raw number, with a vague notion that this is impractical or impossible to achieve. Two points should be considered, though. First, perhaps it isn’t necessary that revenue from the rail route matches the required financing. Perhaps the government can pay for the financing in the short term, and accrue revenue from the rail route to replenish its coffers in the longer term. Second, what is the context for the “1000 per train, 100 services daily” figure? How does it compare to other high speed rail systems in other countries?

Considering the second point first, here is literally the very next paragraph in the report:

The feasibility report estimates for 2033 with a train configuration of 10/16 cars (750/1200 seats) require 52 trains per day per direction. As of 2016, some of the high-traffic HSR routes like Paris-Lyon (409 km), Shanghai-Nanjing (311 km) and Tokyo-Shin Osaka (552 km), though being parts of bigger networks themselves, have more than 85, 300 and 330 trains respectively running every day.

Well, then! In context, the “100 trains per day” number doesn’t look so bad, does it? Considering this information, perhaps the first point above regarding financing isn’t that big a concern, either? It would seem so from the report, since it makes no further comment regarding this matter, including in its conclusions.

There are other points that the news articles mention, such as the 500km distance of the route, as being detrimental to the success of the project (“Flights only take one hour!”). Even those points are considered and answered in the report. The report really is worth the read.

The pros and cons of a large, time-consuming, and expensive government project should be debated — ernestly. However, the debate is derailed (forgive the pun) right at the beginning if the information being circulated is incomplete, or worse, plain wrong. Please, by all means, have the debate. Would everyone at least read the report that everyone is attempting to cite?

P.S.: Between the time that I found and read the report, and I finished writing this piece, the webpage hosting the report seems to have gone dead. No matter, the Wayback Machine has it cached. Go read!


☞ Radiolab Podcast: Using flickering lights to treat Alzheimer's Disease

Permalink - Posted on 2017-06-14 04:00

Today, a startling new discovery: prodding the brain with light, a group of scientists got an unexpected surprise – they were able to turn back on a part of the brain that had been shut down by Alzheimer’s disease. This new science is not a cure, and is far from a treatment, but it’s a finding so … simple, you won’t be able to shake it. Come join us for a lab visit, where we’ll meet some mice, stare at some light, and come face-to-face with the mystery of memory. We can promise you: by the end, you’ll never think the same way about Christmas lights again.

I’ve been meaning to post about this particular episode ever since I listened to it. This is the Nature paper about this study. They found that simply flashing light of a certain frequency at a certain interval helps with some of the brain waves that are diminished in mice with Alzheimer’s. It’s absolutely fascinating.

(I’m not going into too much technical jargon here; go listen to the episode!)

If you don’t listen to Radiolab in general, you definitely should; it’s one of the best podcasts there are.


☞ UK Election: Interesting logistics of the Queen's speech

Permalink - Posted on 2017-06-13 04:00

In light of the recent election in the UK, the Queen, of course, is supposed to make a speech regarding forming the government by the party that has won majority. Now, however, after the interesting results of the election, the Queen’s speech is delayed, and the reason for it is very interesting.

The Telegraph UK reports:

The Queen’s Speech is going to be delayed because it has to be written on goatskin paper and the ink takes days to dry.

Apparently, the British monarchy are more concerned than others would be about the archival qualities of the paper that they use.

[…] goatskin paper is not actually made from goatskin.

The material is in fact high-quality archival paper which is guaranteed to last for at least 500 years.

Well, okay, but still, why the delay?

Well, ink on this special paper takes a few days to dry. And the monarchy had “ready to go” versions of the speech for (a) a Conservative party majority, and (b) a Labour party majority. But the results of the election, that resulted in a hung parliament, has put all pre-made plans into disarray. Since the political parties themselves don’t know yet how the government will be formed, the Queen’s speech isn’t finalized yet either.

Once the details are set in stone they can be committed to the goatskin paper and sent away for binding before being presented to the Queen.

I love how even the most apparently mundane things become fascinating just by being associated with the British monarchy.


☞ Everyday bat vocalizations are rich and complex

Permalink - Posted on 2017-05-29 04:00

In this study, we continuously monitored Egyptian fruit bats for months, recording audio and video around-the-clock. We analyzed almost 15,000 vocalizations, which accompanied the everyday interactions of the bats, and were all directed toward specific individuals, rather than broadcast. We found that bat vocalizations carry ample information about the identity of the emitter, the context of the call, the behavioral response to the call, and even the call’s addressee. Our results underline the importance of studying the mundane, pairwise, directed, vocal interactions of animals.

This is brilliant. They were able to correlate their data analysis of the bats' vocalizations with the behavior and responses that they observed… so now we know more about how bats communicate! Simply by listening to the vocalization, the context, addressee, and even “the outcome of the interaction can be predicted above chance level”. Fascinating.

From the discussion:

It is important to note that we used one set of acoustic features for classification. However, many other multi-dimensional spectro-temporal representations can be tested. The bat’s brain could thus be using some other representation that encapsulates much more information regarding different social aspects. The bat may be able to classify the context of an interaction with higher confidence, based on some acoustic feature which it evolved to use and is yet to be determined. Our analysis is thus probably only a lower bound on what a bat is capable of extracting from aggressive social vocalizations. For example, we did not include any temporal information in our analysis.

In any acoustic signal, and especially where communication is involved, the time parameter is usually crucial and will add rich layers of information. For example, just imagine taking a piece of human speech, and (a) only looking at the overal speech parameters, versus (b) observing how the speech parameters change during the speech. Case (b) will provide far more information than case (a). I think we will discover over time that bats have a pretty well-evolved communication scheme.

This is fascinating stuff.


☞ How Bayesian inference works

Permalink - Posted on 2017-05-28 04:00

Bayesian inference is a way to get sharper predictions from your data. It’s particularly useful when you don’t have as much data as you would like and want to juice every last bit of predictive strength from it.

Although it is sometimes described with reverence, Bayesian inference isn’t magic or mystical. And even though the math under the hood can get dense, the concepts behind it are completely accessible. In brief, Bayesian inference lets you draw stronger conclusions from your data by folding in what you already know about the answer.

An excellent, simple introduction to Bayesian inference. This uses practical examples and an abundance of visual guides: especially useful if you don’t have an extensive math background.


Music: lyrics for Haowaay Pa, from Rupam Islam's Notun Niyom

Permalink - Posted on 2017-04-25 04:00, modified on 2017-05-24 04:00

From Rupam Islam’s new solo album Notun Niyom, here are the lyrics to Haowaay Pa. (Notun Niyom is available to listen on Spotify!)

(P.S.: I really don’t like the spelling ‘haowaay’, so: here’s ‘Hawaye Pa’ by Rupam Islam.)

Song: Hawaye Pa
Album: Notun Niyom

phirbo na, ami phirbo na
shunechi je daak nishachori-r

phirbo na, ami phirbo na
shunechi je daak nishachori-r
karnish bohu-tol, halka chokher jol
tar cheye halka sarir

jibon amar kache ekhono lukiye achhe
jibon ki somoyer daash
hawaye pa, amar hawaye pa
ar batashe amar biswas

jibon amar kache ekhono lukiye achhe
jibon ki somoyer daash
hawaye pa, amar hawaye pa
ar batashe amar…

arekbar, hya arekbar
ghum ar tondrar shima-rekhaye
dekhi nishachori tumi eshe dakcho jemon kore
megh brishti ke deke jaye

arekbar, hya arekbar
ghum ar tondrar shima-rekhaye
dekhi nishachori tumi eshe dakcho jemon kore
megh brishti ke phire chaye

nishachori tumi eto akorshoniyo
je shudhu tomar prorochonaye
hawaye pa, amar hawaye pa
dilam hawaye pa nirdidhaye

jibon amar kache ekhono lukiye achhe
jibon ki somoyer daash
hawaye pa, amar hawaye pa
ar batashe amar biswas

jibon amar kache ekhono lukiye achhe
jibon ki somoyer… daash
hawaye pa, amar hawaye pa
ar batashe amar…


Music: lyrics for Daniken, from Rupam Islam's Notun Niyom

Permalink - Posted on 2017-04-25 04:00, modified on 2017-05-24 04:00

Rupam Islam is out with a new solo album, Notun Niyom. Continuing with tradition, here are the lyrics to Daniken from this album. (Notun Niyom is available to listen on Spotify!)

Song: Daniken
Album: Notun Niyom

gobeshona-tona tomake manaye
amar agroho sotto janaye

gobeshona-tona tomake manaye
amar agroho sotto janaye
gobeshona tumi koro e-niye
phola-phol pele diyo janiye

chola-chol kori kolpona te
abhijan tai na-hanyate
maddhom mon ar lekhoni
lupto danar shonjiboni

icche-ra shob kobita paray
bhabchi-bhabbo gondho choray
tomar icche bhobisshoter
sondhan dey notun pother

bole cholo jai se-pothe haati
eta mohakash-jaaner maati
control-e thak khoka-o-khuku
shokti utsho surjo-tuku

promaner tumi upashok tai
amar shopne tomakei chai
juktir jaale amar hridoy
obohele kore nile tumi joy

tumi ki nijeke byartho bhabo?
tomake ami e-gaan shonabo
aaloker goti amar gaane
chhutbe notun surjo-taane

tumi ki nijeke byartho bhabo?
tomake ami e-gaan shonabo
aaloker goti amar gaane
chhutbe notun surjo-taane

he-prachin, he-probin
he-aadim mohakash
lukiye rekhecho
bhule jawa itihaash

smriti-te tobu kaar
protiddhoni shunte pai
probashi aakashi
se ki kono… debota-i?

tomar totto bhaota hole
chok-choke kono rangta hole
chaota-ke ami beshechi bhalo
rangta amar rong pheralo

bhaota gaiche prithibir gaan
rangta ghochalo rashtro-nishan
aami prothagoto dhormo-bihin
aami gaai Lennon-er Imagine

moha purushera tader juuge
chole-asha rewaj-er hujuge
bhondo akkha peyei thaaken
Jesus Christ-o krush-e jhulechen

ekdin tumi patta pabe
tomar totto proman hobe
shopno sophol hobe amar-o
tokhon amay khujte paro

ekdin tumi patta pabe
tomar totto proman hobe
shopno sophol hobe amar-o
tokhon amay khujte paro

he-prachin, he-probin
he-aadim mohakash
lukiye rekhecho
bhule jawa itihaash

smriti-te tobu kaar
protiddhoni shunte pai
probashi aakashi
se ki kono… debota-i?

debota-i?


☞ Duck Tales 2017, first look

Permalink - Posted on 2017-03-03 05:00, modified on 2017-05-24 04:00

They’re remaking Duck Tales! Woo-hoo-ooo! (And now it’s stuck in your head, right? 😃)

(Featuring David Tennant as Scrooge McDuck!)

Looks great!


☞ Recent ISRO satellite launch carried special imaging constellation

Permalink - Posted on 2017-02-27 05:00, modified on 2017-05-24 04:00

From the website of the company ‘Planet’, published the same day the ISRO satellites were launched:

Today Planet successfully launched 88 Dove satellites to orbit — the largest satellite constellation ever to reach orbit. This is not just a launch (or a world record, for that matter!); for our team this is a major milestone. With these satellites in orbit, Planet will reach its Mission 1: the ability to image all of Earth’s landmass every day.

This constellation therefore formed the majority (88 of 104 satellites launched) of the payload carried by the last ISRO launch. As of this launch, Planet is operating 149 satellites in Earth orbit — this is no mean feat.

Also, an interesting side note: ISRO’s previous largest payload that I referred to in my last post — 20 satellites launched in June 2016 — also seems to be for this same company:

This is our 15th launch of Dove satellites and second aboard India’s PSLV. The launch of Flock 3p comes off the successful launch of Flock 2p on the PSLV in June 2016


☞ Indian Space Research Organization launches satellites, breaks record

Permalink - Posted on 2017-02-15 05:00, modified on 2017-05-24 04:00

Indian Space Research Organisation (ISRO) scripted history today by successfully launching a record 104 satellites, including India’s earth [sic] observation satellite, on a single rocket from the spaceport in Sriharikota. This is the highest number of satellites ever launched in a single mission.

The previous record was held by Russia, with 37 satellites launched at one go. The 104 satellites include 3 of India’s own and 101 of ISRO’s international customers, including 96 from USA. (The article states ISRO’s previous record as 23 satellites launched together in June 2015, but I can’t find a record for that. The closest I could find was this: 20 satellites launched in June 2016.)

As much as this is making news, and as much as ISRO should be proud, this should come as no surprise for space enthusiasts— ISRO has been quite a force in space technology, especially using its PSLV launch system, for quite some time now.

The four stage Polar Satellite Launch Vehicle (PSLV), used for this launch, was developed by ISRO in the 1990s to launch satellites into Sun-synchronous orbits for its own remote sensing satellites. (Other than ISRO, only Russia commercially launches satellites into Sun-synchronous orbits.) PSLV was also used by ISRO for Chandrayaan 1, its lunar probe, and Mangalyaan, its Mars orbiter, becoming only the fourth space agency to reach Mars orbit.

As an aside, the Sun-synchronous orbit is a very interesting concept: it is an orbit where the satellite passes over any given point on Earth’s surface at the same local solar time. This allows the satellite to be in constant sunlight as it passes over particular regions— which is great for imaging, remote sensing, spying and weather applications. The technicalities of such an orbit are very involved and very interesting: look up the Wikipedia page I’ve linked to above.

Fun fact: due to the mechanics of the orbit, a sun-synchronous orbit is stable without external thrust only on oblate spheroid planets. This means that such orbits work on Earth and will work on Mars, but on almost spherical planets such as Venus, it will require external thrust to maintain its orbit.


☞ Hoshino — Star Wars fan film

Permalink - Posted on 2016-11-03 22:41, modified on 2017-05-24 04:00

Must watch. Worth every second of the 7 minutes you will invest.


☞ Hydrogen map of the sky to show the Sun's motion in the galaxy

Permalink - Posted on 2016-11-02 21:18, modified on 2017-05-24 04:00

I know this can be hard to picture in your head, but the beauty of it is that once you do, this map sings. You can instantly see what’s what: the motion of the gas, where it’s more dense than other locations, how it’s distributed. It also shows our location in the galaxy! All those changing velocities depend on the Sun’s velocity, the velocity of the gas, but also the direction of the Sun’s motion and its position in the Milky Way’s disk. That’s a stunning amount of information.

This is fascinating.


Of Alien Megastructures

Permalink - Posted on 2016-10-28 21:34, modified on 2017-05-24 04:00

They call it Tabby’s star. It is a main sequence star quite similar to our Sun, and is about 1500 light years away from us, in the region of the constellation Cygnus. And it’s a particularly odd one. It was studied using the Kepler Space Observatory, which is the space telescope used for identifying planets orbiting distant stars. All of the exoplanet discoveries in the news over the past few years is due to Kepler.

To understand what’s odd about Tabby’s star, we need to know how Kepler operates. What it does is measure — very accurately — the apparent brightness of stars over time. If the apparent brightness of a star changes, that data is used to find patterns in how much and when the brightness changes occur.

Consider what happens with a planet revolving around a star. The apparent brightness of the star dips every time the planet passes in front — i.e. to observers here on Earth — of the star, and the amount and duration of the dip correlates with the size and velocity of the planet. This process works well, and has helped in the discovery of many, many exoplanets revolving around numerous star systems.

Now that we know the basics, here’s why Tabby’s star is so intriguing. Tabby’s star shows small dips in brightness that are both frequent and non-periodic. It has also shown two large recorded dips separated by two years time. How large are the large dips? Where a Jupiter sized planet would have obstructed the star by about 1%, the large dips obscure the star by as much as 15% to 22%. Whatever is blocking the star light during the major dips is not a planet — it is obscuring almost half the width of the star.

That’s not all. It turns out, even without the obscuring, the light output from Tabby’s star seems to be diminishing over time. It turns out, we have observational data about this star since 1890 (via numerous photographs that contain this star in the image), and it seems to have faded by 20% from 1890 to 1989! Even if such old and long-term data is deemed inaccurate, Tabby’s star has definitely diminished in the recent past, in the era of modern measurements. It seems to dim at a slow steady rate, with one short period of a more dramatic fading.

What could be causing such behavior? A number of hypotheses have been proposed, but none of them fully explain the observations. Could it be a young star with coalescing planetary material floating around it? Nope; no such evidence found. Could there be debris from planets that have collided and created clouds of debris and dust? Nope; this is not supported by observations. Could it be a huge number of disintegrating comets orbiting the star? Nope: they wouldn’t obscure the star’s luminosity by as much as 22%.

Well, could it be aliens?

We on Earth are starting to realize how important it is to harness the Sun’s energy as much as we can. We as a civilization have already fantasized about the creation of a huge structure that captures solar energy from every direction, not just from Earth, and using that energy as our planetary energy needs soar. Such a structure is a sphere that “covers” the Sun, and is called a Dyson Sphere, after the scientist who wrote a paper about it in 1960.

Dyson speculated that such a structure would become inevitable as a civilization advances and its energy needs escalate. Realistically, of course, the “sphere” wouldn’t be an actual sphere (imagine how big the sphere would have to be, and how it would revolve around the Sun!), but a “swarm” of smaller objects revolving around the Sun, like satellites. Collectively, they would serve a similar purpose.

What if the observations of Tabby’s star are the tell-tale signs of an alien civilization building a Dyson Swarm? It would explain the long-term fading, and also the sharp dips in its brightness. It would not be a planet; it’d be an artificial mega-structure being slowly constructed. Such construction projects could very easily — by design — obscure 22% of the star’s luminosity.

It’s an idea, and it’s a pretty fantasy for earthlings in the infancy of space-flight, but this idea does have its caveat. An advanced civilization would most likely have a lot of radio signal emissions (we do too — our TV and radio signals are propagating into space at the speed of light) that we should be able to detect. The SETI (Search for Extra-Terrestrial Intelligence) project spent two weeks studying the star system in October 2015, but did not find any technology-related radio signals in multiple frequency spectra.

If you can’t contain your excitement about the possibility of alien life, you still have hope. Whatever the caveat, and however slim the chances, scientists have not been able to rule out this possibility. More studies are planned that will devote resources — including that of SETI — towards studying Tabby’s star and its surroundings, and we will know more in 2017. If they’re really an advanced alien civilization, for all we know, they might have decided (and have the capability) to stop their radio signals from propagating into deep space!

If you’re apprehensive about finding aliens capable of — and in need of! — harnessing all of its star’s energy, you still have hope. What are the chances? For all the advancements we have made in astronomy and the study of the heavens, we really do yet have a lot to learn. When we observe anomalous behavior through our telescopes, the anomaly is due to limitations in our technology or understanding. What are the chances that this is the one case where our knowledge is perfect and the observations are unnatural?

Either way, this is one star we are certain to keep in our sights. The next few years will tell us more — about how little we know about the stars, or about how we’re not alone in the universe.

Updates:

  • This recent paper confirms that Tabby’s Star has faded throughout the duration of it being observed by Kepler. Other stars were also observed at the same time, and none of them fade at such a drastic rate. (doi:10.3847/2041-8205/830/2/L39)
  • The “Breakthrough Listen” project, backed by Prof. Stephen Fleming Hawking (oops, bad typo!) and funded by $100 million, will be used to observe Tabby’s star.

(This piece first appeared in the 2016 edition of Sharod Sombhar, an annual magazine from the Bengali Students’ Association at Virginia Tech.)


☞ Penn and Teller — fooled by a card trick

Permalink - Posted on 2016-09-02 03:12, modified on 2017-05-24 04:00

If you like card tricks, you’ll love this.


☞ A hermit crab changes home; brings house guests along

Permalink - Posted on 2016-09-02 02:55, modified on 2017-05-24 04:00

I’m always fascinated by documentaries about marine life, and I found this quite brilliant.

How the crab invites its house guests to come along to its new house is particularly interesting.

(I won’t say any more; go watch.)


☞ Britain has voted to leave the European Union

Permalink - Posted on 2016-06-24 03:57, modified on 2017-05-24 04:00

Britain has voted to leave the European Union, a historic decision sure to reshape the nation’s place in the world, rattle the Continent and rock political establishments throughout the West.

With 309 of 382 of the country’s cities and towns reporting early on Friday, the Leave campaign held a 52 percent to 48 percent lead. The BBC called the race for the Leave campaign shortly before 4:45 a.m., with 13.1 million votes having been counted in favor of leaving and 12.2 million in favor of remaining.

The value of the British pound plummeted as financial markets absorbed the news.

This is historic. Only time will tell whether the net effects will be good or bad — for Britain and for the European Union. (I haven’t followed the intricate details of the pros and cons, but I understand that the full effects and implications are hard to predict if only because the interactions and agreements between countries are so intertwined.)

P.S. — The following are required viewing:


Gallons per 100 Miles — The Calibration Chart

Permalink - Posted on 2016-06-09 15:45, modified on 2017-05-24 04:00

In the US, automobile fuel economy is usually measured in miles per gallon, mpg. This works, but there is a better metric, especially for comparison between values. Gallons per 100 miles is the way to go!

This is very well known, and even I’ve talked about this before. There are numerous online tools to do the conversion from mpg to gallons per 100 miles… but there don’t appear to be any simple conversion or calibration charts for it.

Well, here you are — an easy to use chart to convert between mpg and gallons per 100 miles (or, equivalently, from km/l to liters per 100km).

What’s wrong with using miles per gallon, though? Well, there’s nothing wrong with using it, of course (we all use it, after all!). It’s that it’s just not a good metric when it comes to comparisons.

This is because the mpg metric is not linear. This means that even a consistent difference in mpg, say a “10 mpg difference”, means different things based on where the difference is calculated from. This makes it very hard to calculate and compare the benefits of better fuel efficiency!

Let’s take a couple of examples and use the chart below. Let’s say you’re planning to shift from owning a 15mpg vehicle to owning a 25mpg vehicle. What are your fuel savings? On the other hand, say you’re shifting from a 25mpg vehicle to a 35mpg vehicle. What about now?

Gallons per 100 miles Conversion

Gallons per 100 miles Conversion (Download full size here)

Let’s look at the chart. The horizontal axis shows miles per gallon, as indicated. The vertical axis shows gallons per 100 miles, also as indicated. Let’s find approximate numbers for our cases above:

  • 15mpg → ≈ 6.7 gallons per 100 miles
  • 25mpg → 4 gallons per 100 miles
  • 35mpg → ≈ 2.8 gallons per 100 miles

For every 100 miles you drive, a “10mpg improvement” from 15mpg saves you 2.5 gallons (≈ 40%) of fuel. On the other hand, over the same 100 miles and the same “10mpg improvement”, but from 25mpg, you save only 1.2 gallons (≈ 30%) of fuel. See how these numbers are different, even though the mpg metric difference between the two cases remains constant?

The mpg metric would have worked, if our baseline was different. But does anyone ever say: “Hey, I have 3 gallons of fuel; how far can I go with it?” Instead, our question is always: “I need to drive 500miles; how much fuel would I need?”

Go ahead and download the full size chart and keep with you. If you’re in the market for cars, this will come in handy! You know how much you drive; this chart gives you an easy way to measure your particular fuel requirements (or savings).

P.S.: The above chart works with any ratio of units; just keep the units the same between the horizontal and vertical axes. So, for example, the same chart applies for km/l vs. liters per 100km.


☞ Muhammad Ali is no more

Permalink - Posted on 2016-06-04 15:12, modified on 2017-05-24 04:00

A great fighter—“The greatest ever”—but he was so much more than that.

[…] as a young heavyweight champion he converted to Islam and refused to serve in the Vietnam War, and became an emblem of strength, eloquence, conscience and courage. Ali was an anti-establishment showman who transcended borders and barriers, race and religion. His fights against other men became spectacles, but he embodied much greater battles.

Also, these are must watch, if you haven’t seem them already:

Rest in peace, sir.


☞ King Tut's dagger was made from a meteorite

Permalink - Posted on 2016-06-01 20:50, modified on 2017-05-24 04:00

An analysis of the dagger’s blade led by Daniela Comelli, a professor of materials science at the Polytechnic University of Milan in Italy, showed that it contains 10 per cent nickel and 0.6 per cent cobalt, the researchers report in the journal Meteoritics and Planetary Science.

(Also, I really love it when a news article references the actual journal article prominently. Nothing better for the interested reader!)


☞ Mumbai Police go after comedian for "mocking" celebrities

Permalink - Posted on 2016-05-31 02:38, modified on 2017-05-24 04:00

An Indian comedian, known for “edgy”, “controversial” material, apparently created something that pokes fun at Indian mega-stars and national heroes Lata Mangeshkar and Sachin Tendulkar.

And of course, this being India, some people found reason to be outraged. And of course, since these people have political affiliations linked to the government, the police are now “looking into the matter”.

Mumbai police has begun an inquiry into complaint against comedian Tanmay Bhat’s video of a mock conversation with Lata Mangeshkar and Sachin Tendulkar that prompted the Shiv Sena, Bhratiya [sic] Janata Party and MNS to call for action against Bhat and AIB.

The inquiry is based on the complaint by Raj Thackeray’s Maharashtra Navnirman Sena.

Bollywood has also reacted sharply to the comedian’s portrayal of the music and cricket icons, saying it is in poor taste.

Making videos in poor taste is not against the law, people. I have not seen the video; I will go ahead and concede nevertheless that the video is not worth its time on Youtube. OK, then don’t watch it! If no one watches it, guess what happens: they stop making such videos!

I find stuff like this maddening. “Freedom of speech” should be simple to understand, no? I can speak my mind; you can speak yours. Unless you’re putting words in my mouth, or are preventing me from living my life fully, I have no right to stop you making your speech, however offended or outraged I feel. Yes, if I feel your speech is “wrong” or “bad”, I might encourage my friends and family to boycott you. But only my sense of offense should have no effect on the legality of your speech!

The only people with say in the matter are the celebrities in question. Did Sachin Tendulkar complain? No. Did Lata? No! As long as everyone understands that the video was made by someone else and not the celebrities in question, how in the world does legality come into the picture?

Please, let the police do their thing and go after actual crime and actual criminals. “Distasteful” and “offensive” mean very different things than “illegal”.


☞ Minimalist Travel — The World in One Backpack

Permalink - Posted on 2016-05-30 16:08, modified on 2017-05-24 04:00

If you’re looking to travel the world, this is a great list to have around when planning for it. Just enough things to carry, but not too much.

Bookmarked!


☞ Star Wars Episode 4 in one graphic

Permalink - Posted on 2016-05-29 16:00, modified on 2017-05-24 04:00

This is brilliant. Must see, if you’re a Star Wars fan. :-)


Octopress — adding category tags to the blog RSS feed

Permalink - Posted on 2016-05-29 03:00, modified on 2017-05-24 04:00

Right from the beginning, I’ve assigned broad categories to every post I’ve written here. (For example, this is my—very lacking—Health Monitoring series of posts.) However, Octopress does not include these category tags by default into the RSS feed. So if a reader is using an RSS feed-reader app or website, they cannot make use of the assigned categories even if the app or website was capable of doing so.

I’ve now added some code necessary to add the categories to the RSS feed, and this is what I did.

At the outset, here is the code that I added:

Add tags to RSS feed (addtagcode.xml) download
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{% for post in site.posts limit: 20 %}
    <entry>
    <!-- Other items that are included in the feed -->

    {% capture catnum %}{{ post.categories | category_links | size }}{% endcapture %}
    {% unless catnum == '0' %}
        <categories>
        {% for cct in post.categories %}
            {% assign idx=forloop.index0 %}<category>{{ post.categories[idx] }}</category>
        {% endfor %}
        </categories>
    {% endunless %}

    <!-- Other items that are included in the feed -->
    <content type="html"><![CDATA[{{ post.content | expand_urls: site.url | cdata_escape }}]]></content>
    </entry>
{% endfor %}

This code works great, but allow me to confess that I am not sure that this is the optimum implementation. To me this seems inelegant, but until I have a better solution, this performs the function appropriately and perfectly adequately.

I’ve only included the relevant portion and the context in which it must be inserted. (See the comment tags <!-- Other items that are included in the feed -->.)

The meat of the algorithm is from lines 7 through 11.

  • A <categories> tag is defined, and a for loop is executed over post.categories, which contains the list of categories for the post.
  • Within the for loop, each post category is enclosed in a <category></category> tag.

Now I had initially thought that the loop variable (cct here) would inherit sequentially the value of each category in post.categories, but apparently that does not work properly. Therefore, the workaround is to

  • identify the loop index (assign idx=forloop.index0) and
  • use individual values of the categories (post.categories[idx]).

We must use forloop.index0 and NOT forloop.index (both are valid commands; the index key starts numbering from 1) because the array numbering starts from 0, not 1.

OK, now that the meat of the algorithm is done, we must put in some code to handle the “unusual” cases—what happens if a post does not have any categories assigned? Such a scenario is handled by the capture command (line 5) and the unless segment that encloses our actual algorithm. The capture command simply captures a value, in our case the number of categories that exist. We only want to include the categories when they exist, therefore our algorithm is run only unless catnum=='0' i.e. when the number of categories is not 0.

Well, that’s it! I have added the code segment before the actual content of each post, but I don’t think it makes any difference if the segment appears after the <content> tag. It should work fine anywhere within the <entry> environment.


☞ Creating "Linked-List" type posts

Permalink - Posted on 2016-05-28 00:00, modified on 2017-05-24 04:00

One of my long-time to-do’s for this blog was to be able to create “linked-list” type posts, where the main heading points, not to a single webpage for the dedicated blog post, but to an external website of interest. (This type of post has been made famous by John Gruber, who is, incidentally, also the creator of the Markdown syntax.)

Well, now I know how to do this (evidence—this post! Ta-da! The title for this post points to The Candler Blog). It turns out it’s not too difficult, but even so, I had help all the way, from The Candler Blog. He has this same implementation, and it turns out, he also has a blog post dedicated to discussing how he did it!

Okay, so, “Daring Fireball-style Linked List posts,” for the uninitiated, refers to the publishing style of John Gruber’s Daring Fireball. For the most thorough explanation of how this works, see Shawn Blanc’s excellent 2009 article, “The Link Post” […]

But how is it done in Octopress? It’s actually very simple. I got a great deal of help, when I was first setting up the site, from Connor Montgomery, who posted his own link post tutorial a few weeks ago. I have since refined the code on my site beyond what we worked out together.

(The Candler Blog website seems otherwise very interesting as well. Go check it out!)


Of Cricket, Mankad-ing, and the Spirit of the Game

Permalink - Posted on 2016-02-04 01:00, modified on 2017-05-24 04:00

The Under-19 cricket world cup is on, and there has been a lot of controversy about a West Indies bowler running a Zimbabwean batsman out as he came in to bowl. Colloquially, this is called ‘Mankad’-ing, and some people view this form of dismissal as “not quite done”. As it happens every time, lots of people are talking about “spirit of the game” and “no warnings issued to the batsman”.

I think those people are in the wrong.

(Here’s the video.)

What would these same people say when a bowler gets a wicket, but his heel is found to be where the bat is spotted in our case? “Spirit of the game”, and give the batsman out? “Give a warning to the bowler”, and give the batsman out? No, of course not, because the rulebook says some part of the bowler’s foot must stay behind the line. The bowler made a mistake, and is penalized for it.

Well, guess what the rulebook says in this case.

Also, to be clear, backing up itself is not illegal; backing up too early is. ICC playing conditions says that the bowler may attempt this dismissal only if he has not completed his delivery swing. So, in effect, once the bowler is in the middle of rolling his bowling arm over to bowl, the bowler can no longer run the batsman out, and the batsman is free to start backing up.

In my opinion, “spirit of the game” issues should only come up when a) the fielding side resorts to subterfuge, or b) it is “obvious” that the batsman is not attempting to take an advantage, and is behaving as if the play is dead. For examples of this second case, see:

In our present case, the batsman was definitely attempting to take advantage, and his opponent ran him out perfectly legally. The batsman made a mistake, and was penalized for it. What’s wrong with that, and what’s all this about giving the batsman a second chance?!

Play on, I say! (Or in this case, game over!)


On Failure in Metallic Materials

Permalink - Posted on 2015-06-07 12:30, modified on 2017-05-24 04:00

As a continuation of my series on composite materials and health monitoring, I wanted to talk about failure in composites. In writing it, I decided that first I needed to talk about failure in metallic materials. In writing that, it turned out that it was long enough to be a separate post by itself. So here it is, a small primer on failure, especially in metallic materials.

We’ll talk about composites next time.

What exactly is “failure”?

A component is said to have failed when it can no longer perform the task that it was designed for. Failure does not necessarily mean breaking, although sometimes it might. Failure in an engineering sense has as much to do with “what the designer intended” as with “the physical structure itself”.

For example, a bridge may be getting old and developing some cracks here and there. At what point do you say that the bridge is “unsafe for use”? The design and engineering teams set up some criteria to evaluate the structure. For example, they might say that “any cracks detected must not be greater than so-and-so length”. This does not mean that the bridge is going to break apart when a crack of that so-and-so length appears. It just means that the engineers are no longer satisfied with how the bridge may hold up in the future. Hence, the bridge component that developed the big-enough crack will be said to have failed.

Tacoma Narrows Bridge

Tacoma Narrows Bridge. (Source)

If the above paragraph seems to convey unnecessary caution on the part of the engineer (why call the bridge unsafe if it isn’t breaking up?), consider that a bunch of reasons go into making such decisions. As an example, the engineers may consider their ability to detect every crack. The engineering team may consider the possibility that they could not detect some defects. What is the probability of a serious defect not being detected?

And there’s good reason to be cautious – if they get it wrong, bridges do collapse.

How do metallic materials fail?

In the previous section, we have been talking about cracks. Here’s why they form in the first place. Cracks form when the load on a given region of a component (i.e. stress, = force per unit area) becomes higher than what the material can handle. This may be because an unexpected amount of load was put on the structure that it was never designed for. It may also be that the capacity of the structure to withstand stresses has diminished over time as the component has aged. In any case, when the stress is too much for the component to bear, the component fractures and develops a crack. The particular mechanics of the fracture itself is a vast area of study in itself, and is way beyond the scope of this piece. Suffice to say, that crack formation weakens the component, and the larger the crack gets, the worse in condition the component becomes. Ultimately, the crack will grow large enough that the component will break into two, and will be unable to take any load at all.

Crack propagation under fatigue loading

Crack propagation under certain conditions. (Source)

For metallic components, since the material itself is nominally homogenous (nominally, because nothing can be perfectly homogenous, but for all intents homogeneity may be assumed), the crack that ultimately causes the material to fail usually occurs where the stress happens to be the greatest. Further, as I mentioned above, the formation of a crack weakens the material, and so once a crack does form, any further worsening in that region accumulates around the same crack (weak zone) instead of creating new cracks all the time. “Where the stress is greatest” usually depends on the geometry of the component, on how the loads are distributed, and, indeed, on tiny variations in the homogeneity of the material itself.

Crack propagation in glass shot at extremely high frame rate. (Source)

For metals, therefore, the mantra for evaluating the component may be condensed as: “follow the cracks”. Wherever a crack seems to be worsening, is where final failure will most likely occur.

That’s it for today’s discussion on crack propagation; next time we’ll get to what I had actually set out to discuss – failure in composites.


On India's World Cup performance (they lost today)

Permalink - Posted on 2015-03-26 13:24, modified on 2017-05-24 04:00

It’s always gutting to see your team lose, isn’t it. Gutting, and infuriating. “They should have won! If only they’d played better!”

Let’s think back though, to the beginning of the World Cup, before a ball had been bowled. Remember those days, just after the triseries with Australia and England? What if someone had said then that India would reach the semifinal? We’d have smirked. “With this team? This bowling attack?” Winning 7 games on the trot? Smirk. 70 wickets in 7 games? Best economy rate as a bowling unit? Cohesive batting performance from the entire unit? Fast bowlers bowling with pace and discipline? Smirk; smirk; smirk.

India have done well to reach the semifinals. They’ve been an excellent team. Their flaw today was that they were not a great team. But that’s okay, being excellent isn’t half bad.

Yes, they had a collective off-day. The bowlers sprayed it around a bit, uncharacteristically. The batters got out in inopportune moments, uncharacteristically. Dhawan usually scores big once he gets a start (and gets a catch dropped). Kohli usually gets himself in and ups his scoring rate, and doesn’t get out at all. There’s usually always Rahane, and even Raina has scored a hundred this world cup. Usually; just not today.

They came across a genuinely better team today, and lost. No shame in that; that takes nothing away from their excellence. Then too, they actually brought Australia back from what looked to be a certain 360+ score. That’s something in itself, no?

Also, a thought: how many teams have defended their world cup titles successfully? West Indies in the 1970s, and Australia in the 1990s and 2000s. It needs a great team, not merely an excellent one, to be able to defend trophies across four year periods and in different conditions. Would we call this Indian team “great”, comparable to the West Indian and Australian teams of before? Definitely not, right? Not yet. Maybe with time and more experience, and maybe a couple of different players, but certainly not yet.

So they came across a better team. They lost. So what? They played well until they lost; they played with pride and with skill and with passion and with excellence.

They kept the Tricolor flying high. Let’s be proud of that.


☞ So-called "Scientist" bets against science; loses

Permalink - Posted on 2015-03-15 21:37, modified on 2017-06-01 04:00

This is from the BBC:

A German biologist who offered €100,000 (£71,350; $106,300) to anyone who could prove that measles is a virus has been ordered by a court to pay up.

Stefan Lanka, who believes the illness is psychosomatic, made the pledge four years ago on his website.

The reward was later claimed by German doctor David Barden, who gathered evidence from various medical studies. Mr Lanka dismissed the findings.

The guy is a biologist? I can understand a non-scientist being deeply skeptical of journal articles and medical findings… but a biologist?

The institution that gave him his degree(s) should consider rescinding whatever degree(s) he has, because:

(a) he clearly cannot review scientific literature and gain an understanding of a subject by himself.

(b) he clearly cannot follow a trail of logic and scientific understanding through published medical research even when it is presented to him by someone else.

Here’s how human society works — we all have our own specializations, and it’s part of our responsibility as specialists to help out others who aren’t knowledgeable in, and cannot tell good from bad, or even have an understanding of, our area of expertise. This isn’t just for “scientists”, of course, but for everyone.

Imagine how little we in general know about the inner workings of our automobiles compared to the expert (mechanic) who’s in charge of fixing them. Now imagine a person who calls himself a mechanic, but (a) doesn’t understand how a certain system in the car works, and (b) cannot follow the logic, and doesn’t believe it when another mechanic shows it to him! Would you ever go solicit this person’s expertise again?

This ‘biologist’ is like our hypothetical mechanic.


☞ Elementary school dumps homework; parents are 'outraged'

Permalink - Posted on 2015-03-11 01:56, modified on 2017-06-01 04:00

From dnainfo.com:

A public elementary school is abolishing traditional homework assignments and telling kids to play instead — outraging parents who say they may pull their kids out of the school.

Teachers at P.S. 116 on East 33rd Street have stopped assigning take-home math worksheets and essays, and are instead encouraging students to read books and spend time with their family, according to a letter the school’s principal, Jane Hsu, sent to parents last month.

This is excellent on the part of the school. Allowing kids the time and the encouragement to do other things is, I think, a crucial part of a child’s development that we as a society have forgotten to focus on. We’ve become so enamored with the idea of “learning” that we’ve forgotten that “education” isn’t just found in schools. A well-rounded character and an indepedent mind are just as important, and non-school activities can be crucial in developing those aspects.

From a parent:

“They’ve decided that giving homework to younger ages [elementary school students] isn’t viable. I don’t necessarily agree. I think they should have homework — some of it is about discipline. I want [my daughter] to have fun, but I also want her to be working towards a goal.”

Take everything in that statement, only take out the word “homework” from it. Yes, kids should learn. Yes, discipline is part of it. But why should learning feel like “work”? Find them activities, and teach them discipline, and the ideas of working towards a goal, with something other than school activity.

Parents — please don’t freak out. This is good for your kids. Let the schools decide how they want to impart the education that they need to impart. Meanwhile, your kids having more free time is a good thing (even if it sometimes means more headache on you!). They can use this time productively, and it’s up to you help them be productive. Find them books; introduce them to hobbies; open them up to music and sport and writing and painting — and whatever else your kids may find interesting!

Other schools — please consider similar measures! While some homework is okay, there’s often too much of it, and tends to sap much of the fun and sense of fulfilment that an education can be.

When we think about shaping the development of our next generation, we might do well to re-evaluate our childhood with the added clarity of hindsight. What did we love, and what did we hate; what things helped us, and what things were a disadvantage? How must things be different for a generation that’s removed from ours by an entire generation? We experienced childhood a certain way, and even if our childhood was the best possible, that doesn’t mean that it remains the best way for a future generation.


Thoughts on Interstellar, the movie (spoilers!)

Permalink - Posted on 2014-11-08 07:13, modified on 2017-06-01 04:00

This post contains spoilers. Please go watch the movie, and then read this. Seriously, go watch. This is an all-time movie, and I have a feeling this will stand the test of time and gain even more popularity as time goes on. This one is that good.

I just had to jot down some thoughts about the movie — and particularly the science therein. One, I’m interested in this stuff, and can’t help it. But also, two, I heard people pooh-poohing it away, and I didn’t like that at all. So here goes.

In summary: I loved it. This is what science-fiction is supposed to look like — a combination of adventure and extrapolation of real science into the unknown. I’ve been reading and hearing some of the negative ‘reviews’, and it seems to me that most of it revolves around “hey, that’s not science, it’d never work that way!” The great thing about this movie is most of the ‘extrapolations’ are in directions that are truly unknown, and until science does cover those areas, your, mine, and the Nolans' imagination is as good as anyone’s.

  • I loved the scientific accuracy. I usually hate it when films get their premises wrong. This one got the science right — mostly. (We’ll go into details soon.)
  • I loved that a wormhole near Saturn wouldn’t just appear out of thin vacuum. I loved that they didn’t create some bunkum theory for man to create a wormhole, and just went with “we don’t know”.
  • I loved that tidal wave on the first planet. That wasn’t just there as a plot point — being near a black hole is supposed to cause that. Giant tidal forces should be a norm near a black hole, and it was.
  • I did NOT like the fact that a planet could exist so near to a black hole. I think they showed the planet to be basically situated right near the ‘edge’ of the black hole, and at that distance, with a planetary mass, the tidal forces should work on the solids too, and basically tear the planet apart. Crucially, it’s not impossible, though. (Here again, they’re stretching the limits of the science, at most. Lovely.)
  • I did NOT like the fact that 23 years elapsed on the spaceship in orbit, when only a few (three?) hours elapsed on the surface of the first planet.

    Remember, it’s not the gravity of the planet that’s causing the time-dilation, but the nearby black hole. So the premise is that they ‘parked’ the orbiting space craft at such a distance that time dilation effects were negligible, when compared to that at the planet surface.

    Now remember that they took 8 months to travel to Mars, and 2 years to travel to Saturn. Granted, they were using gravity assists and not direct thrust, so the interplanetary voyage took longer. But it gives an idea of the orders of magnitude involved here. Let’s say that using direct thrust of the smaller craft they can travel the distance between Earth and Saturn in 3 hours. Fair? (If I’m doing the math right, Earth-Saturn is about 1.5 light-hrs, so light would take 1.5hrs to get there.)

    There’s no way that that distance causes a relative time-dilation of 23 years in the vicinity of a black hole, and does not pulverize the planet itself. That right there was all wrong.

  • I did NOT like that Coop is thrown back into 3D space through the same wormhole that they originally went through. A wormhole is supposed to be like a tunnel. You go in one end; you come out another end. They went in one end (Saturn), and came out somewhere in the vicinity of the black hole, but not out of the black hole itself.

    If so, why would another wormhole originating inside the black hole lead back to an opening to a separate wormhole near Saturn?! That did not sit well with me.

  • I loved the black hole and event horizon sequences and visualizations. I’ll trust Dr. Kip Thorne and Cornell University grad students that they got the details right. It all looked amazing.
  • I loved the treatment of time as “just another dimension to travel through”. Seriously, we don’t really know what happens inside black holes, and one possibility is indeed that 4-dimensional spacetime can be mashed together. Beyond that, as I mentioned earlier, it’s an artist’s realm, and I liked what they did with it. It was convenient, of course, that the particular area of spacetime that Coop confronted from within the black hole was precisely the spacetime that he needed to confront, but we can allow that much cinematic coincidence, can’t we?
  • I did NOT like the idea of conveying through Morse code, via the seconds hand of a wrist watch, no less, experimental data regarding quantum mechanics and relatively. (What other ‘data’ would the robot ‘collect’ from within a black hole?!) I wish they could find a more ingenious way to achieve this.
  • I am okay with the idea that they only needed experimental data from within the black hole to complete their theory of quantam gravity. Perhaps they had a bunch of ‘general solutions’ and the experimental data allowed them to arrive at ‘particular solutions’. Not beyond the imagination, by any stretch.
  • Hans Zimmer, take a bow. Such a brilliant score!
  • I have to watch the movie again. I don’t think I’ve taken it all in, in one sitting. Christopher Nolan, keep making movies.


On avoiding plagiarism

Permalink - Posted on 2014-06-06 04:00, modified on 2017-06-01 04:00

I’ve been a student panelist at the Virginia Tech Graduate Honor System (GHS) for a few years now, and by far the most frequent infractions students are accused of involve some form of plagiarism. In some cases, alas, the students seem perfectly aware of what they’re upto, but very often, it seems that they just didn’t realize that what they were doing was anything wrong, or indeed, anything out of the ordinary.

Unfortunately, whether you knew and understood or not, if you did it, well, you did it. On that note, here are some pointers on avoiding plagiarism.

Let me focus on writing in particular, even though this applies equally well to any other creative task. If I had to summarize the concept in one sentence, I’d put it this way: when you’re writing something, there should be no ambiguity in the reader’s mind as to who actually composed the words in different portions of your document. If the document header contains your name, the assumption is that you wrote it, unless you specify otherwise. You’re perfectly fine using material from other sources and authors—as long you make it explicitly clear as to the authorship of that material.

Let’s say you’re referring to Wikipedia to understand a particular terminology or concept to include in a paper. You have one of two options:

  • Cite Wikipedia as a source, and use the words from Wikipedia within quotation marks.
  • Or, read and understand the material (but don’t memorize it word-for-word), and then close the webpage. Now try writing about the concept that you just read about. Or better yet, come back in an hour and write about it. Chances are the words you write are your own words and your own understanding, even though you read about it on Wikipedia. You should still cite Wikipedia as the source of your information, of course.

    If, while writing, you find yourself having to refer to the Wikipedia article to “refresh” your memory of the language used, you’d better cite the article and include the relevant portions verbatim, and within quotation marks.

The quotation marks are important in addition to including citations. This is because, as I mentioned above, citations are a must as sources of information, even if the words and compositions are your very own. If you don’t use quotation marks, it appears, of course, that the words are your own. If they aren’t, guess what you’re guilty of!

Also, remember to be sparing in using material verbatim from sources. A couple of sentences at most, and in rare occasions, perhaps a paragraph or two. If you’re using a paragraph, enclose the entire paragraph in quotation marks, and/or consider italicizing or indenting the paragraph to distinguish from your other paragraphs. Remember, your article is your own, and should almost entirely comprise your sentences. (This seems like a no-brainer, but I’ve seen instances where almost the entirety of a write-up has been “compiled” from various sources.)

There are some excellent resource on the internet about avoiding plagiarism. Here’s one: http://www.plagiarism.org/plagiarism-101/what-is-plagiarism.

To repeat once again, there should be no ambiguity as to the authorship of any portion of your work. Make it clear and cite the source, and you’ll be fine. Please, don’t get caught in embarrassing situations only because you didn’t know better. :)


This may be the best journal article ever

Permalink - Posted on 2014-04-21 03:48, modified on 2017-06-01 04:00

I was forwarded a PDF of a journal article by friends, and I had a hard time believing when I read it. This has to be the best journal article ever; it even includes comments from a reviewer (which is not common at all, at least in my area of research).

Here’s the link to the article listing at nih.gov, and here’s a link to the PDF itself.

Enjoy.