Teaching Blog of Ioannis Souldatos

Here you will find material about Ioannis Souldatos’ teaching and material from other instructors or from the web that I found interesting.

Advertisements

Laura Kipnis Says She Faced Another Title IX Investigation, This Time for Her Book

See full article at http://www.chronicle.com/blogs/ticker/laura-kipnis-says-she-faced-another-title-ix-investigation-this-time-for-her-book/

September 20, 2017 by Andy Thomason

Laura Kipnis Says She Faced Another Title IX Investigation, This Time for Her Book

Laura Kipnis, the Northwestern University professor whose Chronicle article titled “Sexual Paranoia Strikes Academe” sparked a chain of events that led to a Title IX investigation of her, faced another inquiry, The New Yorker reports. That one was prompted by the publication of her book Unwanted Advances: Sexual Paranoia Comes to Campus, she said.

In her initial essay in The Chronicle, Ms. Kipnis argued that a culture of protection rather than empowerment around sexual issues on campuses was wrongheaded. The response to that essay included the filing of a Title IX complaint against Ms. Kipnis, alleging, in part, that the essay had had a chilling effect on complaints, and an investigation was opened. She chronicled the proceedings in another Chronicle essay, “My Title IX Inquisition,” and was cleared of wrongdoing.

But over the summer, The New Yorker reports, Ms. Kipnis faced another university investigation, prompted by the publication of her new book. The allegations, according to the magazine, were similar to those of the first complaint. In a statement to the university, Ms. Kipnis wrote that “these complaints seem like an attempt to bend the campus judicial system to punish someone whose work involves questioning the campus judicial system, just as bringing Title IX complaints over my first Chronicle essay attempted to do two years ago.”

She was cleared of violating university policy, the magazine says. Northwestern did not respond immediately to The New Yorker’s request for comment.

Carbon dating reveals earliest origins of zero symbol

See full article at: http://www.bbc.com/news/uk-england-oxfordshire-41265057

Carbon dating reveals earliest origins of zero symbol

  • 15 September 2017

Carbon dating shows an ancient Indian manuscript has the earliest recorded origin of the zero symbol.

The Bakhshali manuscript is now believed to date from the 3rd or 4th Century, making it hundreds of years older than previously thought.

It means the document, held in Oxford, has an earlier zero symbol than a temple in Gwailor, India.

The finding is of “vital importance” to the history of mathematics, Richard Ovenden from Bodleian Libraries said.

The zero symbol evolved from a dot used in ancient India and can be seen throughout the Bakhshali manuscript.

Other ancient cultures like the Mayans and Babylonians also used zero symbols, but the dot the Bakhshali manuscript developed a hollow centre to become the symbol we use today.

It was also only in India where the zero developed into a number in its own right, the Bodleian Libraries added.

Earlier research had dated the Bakhshali manuscript to the 8th and 12th century, but now carbon dating has shown it to be centuries older.

Bodleian Libraries said scholars had previously struggled to date it because it is made of 70 leaves of birch bark and composed of material from three different periods.

The manuscript was found by a farmer in a village called Bakhshali, in what is now Pakistan, in 1881 before being acquired by the indologist Rudolf Hoernle, who presented it to the Bodleian Libraries in 1902.

The creation of zero was one of the “greatest breakthroughs” in mathematics, Prof Marcus Du Sautoy of the University of Oxford said.

Cryptography sets the tone… A story of string instrument making in the 19th century

Article from http://www.loria.fr/en/cryptography-sets-the-tone-a-story-of-string-instrument-making-in-the-19th-century/

Cryptography sets the tone… A story of string instrument making in the 19th century

1 February 2017

Pierrick Gaudry, CNRS researcher in the Caramba team has broken the codes in the accounting registers of major Parisian instrument makers from the 19th century. This deciphering reveals the value of string instruments and provides more knowledge of the history of the instrument-making business.

Jean-Philippe Echard, the curator of the music museum in Paris, found three accounting registers covering a period of nearly 150 years in some archives. These had been kept by the various successors of the great Parisian string instrument maker Nicolas Lupot who founded his workshop in 1795.

These accounts have become yellowed by time but have references to nearly 250 instruments. These were mainly violins bought by the instrument makers with a view to selling them on to their clientele of musicians.

For each instrument, 4 prices were entered – the violin’s purchase price, the desired selling price, the reserve price (the minimum price the instrument maker would accept) and the actual sale price.

The instrument makers coded the purchase price and the reserve price to keep them confidential by replacing numbers with letters. The coding enabled the instrument maker to have the book open in front of clients without the latter knowing his profit margins.

Jean-Philippe Echard therefore contacted Pierrick to ask him to decipher these codes. “In that era, communications were multiplying and coding messages had become fashionable”, explains Pierrick.

Pierrick usually uses powerful calculators for his research but in this case to decipher the codes he just needed a sheet of paper and a pencil. It turned out to be a monoalphabetic substitution cipher. The instrument maker replaced a figure by a letter basing this on a ten-letter word. After trying out a few hypotheses, Pierrick discovered that this code was based on the French word “harmonieux” (harmonious), with the “h” standing for 1 and the “x” for 0 (this was sometimes replaced by “z” as the figure 0 was often used).

Why was the word “harmonieux” chosen? The soundboard – ‘table d’harmonie‘ in French – is the front surface of a violin or any string instrument. It receives the vibration to be amplified, usually via the bridge of the instrument.

Following this discovery, an article was submitted to and accepted by the journal “Cryptologia” which features the historical aspects of cryptography.

This deciphering work revealed numerous secrets about the value of string instruments and more generally on the history of the instrument-making business but also showed that cryptography is not just based on working with computers. It existed long before computers in fact and even involves many other disciplines. The main thing is to make them work together in harmony.

The article can be read on Hal

See the video (copyright – CNRS Images)

Who wants to live forever?

Articles from http://www.sciencesquared.eu/who-wants-live-forever

Who wants to live forever?

We are living longer. How can we live better?

Your mother’s diet, your immune system and air pollution are among the many factors affecting how long you live and whether you develop Alzheimer’s or cancer. ERC researchers are unravelling the secrets of longevity, exploring ways of adding ‘life to years’ as well as ‘years to life’. (Hint: It helps to be a monk.)

Story by Gary Finnegan
Video by Sabina Brennan
Design by Ben Newton.

Let’s start with the good news: most Europeans born today will live long lives – on average, 78 years for men and 83 years for women.

Now the bad news: although they will live longer, they will not live better. Men born today will spend 17 of their years in poor health, and women will be ill 22 years. Hence the adage: ‘women are sicker but men die quicker’.

Nor is this un-healthy ageing problem a European issue only. In rapidly developing nations such as China and India, life expectancy is also on the up – but so too are chronic conditions, including cancer, heart disease, diabetes and dementia. It seems we have added quantity of life without making much progress on quality.

How to Spot Visualization Lies

From http://flowingdata.com/2017/02/09/how-to-spot-visualization-lies/

How to Spot Visualization Lies

Keep your eyes open.

It used to be that we’d see a poorly made graph or a data design goof, laugh it up a bit, and then carry on. At some point though — during this past year especially — it grew more difficult to distinguish a visualization snafu from bias and deliberate misinformation.

Of course, lying with statistics has been a thing for a long time, but charts tend to spread far and wide these days. There’s a lot of them. Some don’t tell the truth. Maybe you glance at it and that’s it, but a simple message sticks and builds. Before you know it, Leonardo DiCaprio spins a top on a table and no one cares if it falls or continues to rotate.

So it’s all the more important now to quickly decide if a graph is telling the truth. This a guide to help you spot the visualization lies.

Hot electronics get magnetic cool

From https://erc.europa.eu/projects-and-results/erc-stories/hot-electronics-get-magnetic-cool

Hot electronics get magnetic cool

20/01/2017

The EU-funded HYMAGINE project has combined conventional electronic transistors with new magnetism-based ‘spintronic’ devices to improve information processing speeds and reduce energy consumption.

Caption: Automatic electrical testing of hybrid CMOS/magnetic chips from HYMAGINE

Faster supercomputers demand ever smaller-scale microstructures if they are to remain on a rising performance curve. Yet as transistors shrink to the nanometre scale, so power densities and temperatures rise – and the materials they are made of can only take so much before breaking down.

HYMAGINE researchers have developed hybrid solutions combining conventional semiconductor (CMOS) components with memory devices based on magnetic tunnel junctions (MTJ). These logic/memory hybrids use much less energy than CMOS-only circuits. The magnetic memory works as fast as existing static random access memory (SRAM), but storage is more stable than SRAMs – just like in (much slower) hard disk drives.

A new spin on old technology

“Conventional electronic CMOS devices are great for logic operations but not so good for working memory,” explains Bernard Dieny who leads this project funded by the European Research Council (ERC) . “Magnetic storage is much better, because of its ability to keep the written information even when the electrical supply is switched off. In HYMAGINE we deposited MTJ memory structures (MRAMs) directly onto commercial CMOS semiconductor wafers and tested the results with great success.”

Basic MTJs have two magnetic layers separated by a thin layer of magnesium oxide. In one magnetic layer the magnetic polarity is fixed, in the other ‘free’ storage layer it can switch. The junction uses ‘spin transfer torque’ to write information, whereby electrons flowing in the device are ‘spin polarised’ and can switch the polarity in the storage layer between two (binary) states. Read operations rely on measuring the resistance through the MgO layer, which is higher with opposed polarities and lower with aligned polarities.

“When testing read/write operations in our junctions we investigated several important properties,” says Dieny. “First we demonstrated that CMOS/MTJ hybrids can operate at industry-standard speeds of around 1GHz. We found they consume a fifth of the energy needed by conventional all-CMOS systems, so they use significantly less power.

“A further critical property is the ‘endurance’ of the junction, which is the number of read/write voltage cycles it can support before failure becomes likely. Standard flash memory such as USB drives will support 100 000 cycles, but we found our hybrids have an endurance of 1015 cycles – almost unlimited for practical purposes!”

Material matters

As endurance is such a critical property for eventual take-up, the HYMAGINE team investigated the physical mechanisms causing device failure. They found that electrons tunnelling through the MgO layer are trapped at lattice defects. Trapping and untrapping of electrons can lead to high stresses in the layer leading to early material breakdown.

“We established that the density of defects, such as incorporated water molecules, must be kept low. Already a number of equipment suppliers are adapting their vacuum equipment to reduce background H2O pressures with an eye on growing markets for MTJ devices,” explains Dieny. “We also found that the endurance of a newly manufactured device can be predicted using a measure of voltage background noise. This is a significant result for chip-makers who can use such measurements as quality control steps in volume manufacturing.”

HYMAGINE also developed advanced computer-based modelling and design tools for CMOS/MTJ hybrids and incorporated these into widely-used industry-standard software packages. Building on this work, a new company eVaderis was set up to offer spintronic design services, and eventually devices to the semiconductor world.

Encouraging crosstalk

“There is too little communication between the ‘microelectronics’ and ‘magnetism’ communities in the semiconductor world, and this is holding back spintronic applications,” says Dieny. “This is why we launched annual summer schools in Grenoble on MRAM technologies – bringing researchers and engineers together to learn more about spintronics.”

Dieny is also taking spintronics further in a new ERC project called MAGICAL, which will add communications and sensor functions to low power CMOS/MTJ hybrids. “If the ‘Internet of Things’ is to advance, then low power devices are a must,” he explains. “Wearable computers, solar-powered sensors, connected pacemakers – they all demand low power solutions, and magnetism-based devices can offer these as HYMAGINE showed.”

Bernard Dieny’s achievement in the field of MRAMs was recognised with the award of the Adrien Constantin de Magny Prize by the French Académie des Sciences in 2015.

UCLA mathematicians bring ocean to life for Disney’s ‘Moana’

Full article can be found at
http://newsroom.ucla.edu/stories/ucla-mathematicians-help-bring-the-ocean-to-life-for-disneys-hit-movie-moana

UCLA mathematicians bring ocean to life for Disney’s ‘Moana’

They bring the magic of realism to animation and apply this new knowledge to solve real-world problems Stuart Wolpert | January 03, 2017

Courtesy of Walt Disney Animation Studios

The hit Disney movie “Moana” features stunning visual effects, including the animation of water to such a degree that it becomes a distinct character in the film.

UCLA mathematics professor Joseph Teran, a Walt Disney consultant on animated movies since 2007, is under no illusion that artists want lengthy mathematics lessons, but many of them realize that the success of animated movies often depends on advanced mathematics.

“In general, the animators and artists at the studios want as little to do with mathematics and physics as possible, but the demands for realism in animated movies are so high,” Teran said. “Things are going to look fake if you don’t at least start with the correct physics and mathematics for many materials, such as water and snow. If the physics and mathematics are not simulated accurately, it will be very glaring that something is wrong with the animation of the material.”