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πŸ”— Rotterdam harbor storm barrier closes for the first time in its history

πŸ”— Civil engineering πŸ”— Netherlands

The Maeslantkering ("Maeslant barrier" in Dutch) is a storm surge barrier on the Nieuwe Waterweg, in South Holland, Netherlands. It was constructed from 1991 to 1997. As part of the Delta Works the barrier responds to water level predictions calculated by a centralized computer system called BOS. It automatically closes when Rotterdam (especially the Port of Rotterdam) is threatened by floods.

Maeslantkering has two 210-metre long barrier gates, with two 237-metre long steel trusses holding each. When closed, the barrier will protect the entire width (360 metres) of the Nieuwe Waterweg, the main waterway of Port of Rotterdam. It is one of the largest moving structures on Earth, rivalling the Green Bank Telescope in the United States and the Bagger 288 excavator in Germany.

Discussed on

πŸ”— Note G

πŸ”— Computing πŸ”— Computer science

Note G was a computer algorithm written by Ada Lovelace, and was designed to calculate Bernoulli numbers using the hypothetical analytical engine. Note G is generally agreed to be the first algorithm specifically for a computer, and Lovelace is considered as the first computer programmer as a result. The algorithm was the last note in a series labelled A to G, which she employed as visual aids to accompany her English translation of Luigi Menabrea's 1842 French transcription of Charles Babbage's lecture on the analytical engine at the University of Turin, "Notions sur la machine analytique de Charles Babbage" ("Elements of Charles Babbage’s Analytical Machine"). Lovelace's Note G was never tested, as the engine was never built. Her notes, along with her translation, were published in 1843.

In the modern era, thanks to more readily available computing equipment and programming resources, Lovelace's algorithm has since been tested, after being "translated" into modern programming languages. These tests have independently concluded that there was a bug in the script, due to a minor typographical error, rendering the algorithm in its original state unusable.

Discussed on

πŸ”— Send Me to Heaven

πŸ”— Apps

Send Me To Heaven (officially stylized as S.M.T.H.) is an Android application developed by Carrot Pop which measures the vertical distance that a mobile phone is thrown. Players compete against each other by seeking to throw their phones higher than others, often at the risk of damaging their phones. The app was immediately banned from the App Store but remains available from Google Play, where it maintains a cult following.

Discussed on

πŸ”— Oi (Interjection)

πŸ”— Linguistics

Oi is an interjection used in various varieties of the English language, particularly Australian English, British English, Indian English, Irish English, New Zealand English, and South African English, as well as non-English languages such as Chinese, Tagalog, Tamil, Hindi/Urdu, Japanese, and Portuguese to get the attention of another person or to express surprise or disapproval. It is sometimes used in Canadian English and very rarely in American English. The word is also common in the Indian subcontinent, where it has varied pronunciations of "O-ee" and "O-ye".

"Oi" has been particularly associated with working class and Cockney speech. It is effectively a local pronunciation of "hoy" (see H-dropping), an older expression. A study of the Cockney dialect in the 1950s found that whether it was being used to call attention or as a challenge depended on its tone and abruptness. The study's author noted that the expression is "jaunty and self-assertive" as well as "intensely cockney".

A poll of non-English speakers by the British Council in 2004 found that "oi" was considered the 61st most beautiful word in the English language. A spokesman commented that "Oi is not a word that I would've thought turned up in English manuals all that often." "Oi" was added to the list of acceptable words in US Scrabble in 2006.

Discussed on

πŸ”— Dynamic Soaring

πŸ”— Aviation πŸ”— Aviation/gliding

Dynamic soaring is a flying technique used to gain energy by repeatedly crossing the boundary between air masses of different velocity. Such zones of wind gradient are generally found close to obstacles and close to the surface, so the technique is mainly of use to birds and operators of radio-controlled gliders, but glider pilots are sometimes able to soar dynamically in meteorological wind shears at higher altitudes.

Dynamic soaring is sometimes confused with slope soaring which is a technique for achieving elevation.

Discussed on

πŸ”— Great horse manure crisis of 1894

πŸ”— Disaster management πŸ”— Economics πŸ”— Urban studies and planning

The great horse manure crisis of 1894 refers to the idea that the greatest obstacle to urban development at the turn of the century was the difficulty of removing horse manure from the streets. More broadly, it is an analogy for supposedly insuperable extrapolated problems being rendered moot by the introduction of new technologies. The phrase originates from a 2004 article by Stephen Davies entitled "The Great Horse-Manure Crisis of 1894".

The supposed problem of excessive horse-manure collecting in the streets was solved by the proliferation of cars, buses and electrified trams which replaced horses as the means of transportation in big cities. The term great horse manure crisis of 1894 is often used to denote a problem which seems to be impossible to solve because it is being looked at from the wrong direction.

The name refers to a supposed 1894 publication in The Times, which said "In 50 years, every street in London will be buried under nine feet of manure". The reasoning was that more horses are needed to remove the manure, and these horses produce more manure. An urban planning conference in 1898 supposedly broke up before its scheduled end due to a failure to find an answer to this problem. No such statement in the Times, nor conference result, is known, but in 1893 London there was a complaint that horse manure, formerly an economic good that could be sold, had become a disposal problem, an economic bad.

The supposed crisis has since taken on life as a useful analogy.

Discussed on

πŸ”— Fractional Fourier transform

πŸ”— Mathematics

In mathematics, in the area of harmonic analysis, the fractional Fourier transform (FRFT) is a family of linear transformations generalizing the Fourier transform. It can be thought of as the Fourier transform to the n-th power, where n need not be an integer β€” thus, it can transform a function to any intermediate domain between time and frequency. Its applications range from filter design and signal analysis to phase retrieval and pattern recognition.

The FRFT can be used to define fractional convolution, correlation, and other operations, and can also be further generalized into the linear canonical transformation (LCT). An early definition of the FRFT was introduced by Condon, by solving for the Green's function for phase-space rotations, and also by Namias, generalizing work of Wiener on Hermite polynomials.

However, it was not widely recognized in signal processing until it was independently reintroduced around 1993 by several groups. Since then, there has been a surge of interest in extending Shannon's sampling theorem for signals which are band-limited in the Fractional Fourier domain.

A completely different meaning for "fractional Fourier transform" was introduced by Bailey and Swartztrauber as essentially another name for a z-transform, and in particular for the case that corresponds to a discrete Fourier transform shifted by a fractional amount in frequency space (multiplying the input by a linear chirp) and evaluating at a fractional set of frequency points (e.g. considering only a small portion of the spectrum). (Such transforms can be evaluated efficiently by Bluestein's FFT algorithm.) This terminology has fallen out of use in most of the technical literature, however, in preference to the FRFT. The remainder of this article describes the FRFT.

Discussed on

πŸ”— Island Gigantism

πŸ”— Evolutionary biology πŸ”— Ecology

Island gigantism, or insular gigantism, is a biological phenomenon in which the size of an animal species isolated on an island increases dramatically in comparison to its mainland relatives. Island gigantism is one aspect of the more general "island effect" or "Foster's rule", which posits that when mainland animals colonize islands, small species tend to evolve larger bodies, and large species tend to evolve smaller bodies (insular dwarfism). This is itself one aspect of the more general phenomenon of island syndrome which describes the differences in morphology, ecology, physiology and behaviour of insular species compared to their continental counterparts. Following the arrival of humans and associated introduced predators (dogs, cats, rats, pigs), many giant as well as other island endemics have become extinct (e.g. the dodo and Rodrigues solitaire, giant flightless pigeons related to the Nicobar pigeon). A similar size increase, as well as increased woodiness, has been observed in some insular plants such as the Mapou tree (Cyphostemma mappia) in Mauritius which is also known as the "Mauritian baobab" although it is member of the grape family (Vitaceae).

Discussed on

πŸ”— Telephone numbers in North Korea

πŸ”— Korea πŸ”— Telecommunications πŸ”— Korea/North Korea

Telephone numbers in North Korea are regulated by the Ministry of Post and Telecommunications.