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๐Ÿ”— Cistercian Numerals (base 10000 digit system)

๐Ÿ”— Mathematics

The medieval Cistercian numerals, or "ciphers" in nineteenth-century parlance, were developed by the Cistercian monastic order in the early thirteenth century at about the time that Arabic numerals were introduced to northwestern Europe. They are more compact than Arabic or Roman numerals, with a single glyph able to indicate any integer from 1 to 9,999.

Digits are based on a horizontal or vertical stave, with the position of the digit on the stave indicating its place value (units, tens, hundreds or thousands). These digits are compounded on a single stave to indicate more complex numbers. The Cistercians eventually abandoned the system in favor of the Arabic numerals, but marginal use outside the order continued until the early twentieth century.

๐Ÿ”— Galton Board

๐Ÿ”— Statistics

The bean machine, also known as the Galton Board or quincunx, is a device invented by Sir Francis Galton to demonstrate the central limit theorem, in particular that with sufficient sample size the binomial distribution approximates a normal distribution. Among its applications, it afforded insight into regression to the mean or "regression to mediocrity".

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๐Ÿ”— Taqi ad-Din Muhammad ibn Ma'ruf

๐Ÿ”— Biography ๐Ÿ”— Biography/science and academia ๐Ÿ”— Egypt

Taqi al-Din Muhammad ibn Ma'ruf ash-Shami al-Asadi (Arabic: ุชู‚ูŠ ุงู„ุฏูŠู† ู…ุญู…ุฏ ุจู† ู…ุนุฑูˆู ุงู„ุดุงู…ูŠโ€Ž, Ottoman Turkish: ุชู‚ูŠ ุงู„ุฏูŠู† ู…ุญู…ุฏ ุจู† ู…ุนุฑูˆู ุงู„ุดุงู…ูŠ ุงู„ุณุนุฏูŠโ€Ž, Turkish: Takiyรผddin) (1526-1585) was an Ottoman polymath active in Cairo and Istanbul. He was the author of more than ninety books on a wide variety of subjects, including astronomy, clocks, engineering, mathematics, mechanics, optics and natural philosophy.

In 1574 the Ottoman Sultan Murad III invited Taqฤซ ad-Dฤซn to build the Constantinople observatory. Using his exceptional knowledge in the mechanical arts, Taqฤซ ad-Dฤซn constructed instruments like huge armillary and mechanical clocks that he used in his observations of the Great Comet of 1577. He also used European celestial and terrestrial globes that were delivered to Istanbul in gift-exchange.

The major work that resulted from his work in the observatory is titled "The tree of ultimate knowledge [in the end of time or the world] in the Kingdom of the Revolving Spheres: The astronomical tables of the King of Kings [Murฤd III]" (Sidrat al-muntah al-afkar fi malkลซt al-falak al-dawฤrโ€“ al-zij al-Shฤhinshฤhi). The work was prepared according to the results of the observations carried out in Egypt and Istanbul in order to correct and complete Ulugh Beg's Zij as-Sultani. The first 40 pages of the work deal with calculations, followed by discussions of astronomical clocks, heavenly circles, and information about three eclipses which he observed at Cairo and Istanbul. For corroborating data of other observations of eclipses in other locales like Daud ar-Riyyadi (David the Mathematician), David Ben-Shushan of Salonika.

As a polymath, Taqฤซ al-Dฤซn wrote numerous books on astronomy, mathematics, mechanics, and theology. His method of finding coordinates of stars were reportedly so precise that he got better measurements than his contemporaries, Tycho Brahe and Nicolas Copernicus. Brahe is also thought to have been aware of al-Dฤซn's work.

Taqฤซ Ad-Dฤซn also described a steam turbine with the practical application of rotating a spit in 1551. He worked on and created astronomical clocks for his observatory. Taqฤซ Ad-Dฤซn also wrote a book on optics, in which he determined the light emitted from objects, proved the Law of Reflection observationally, and worked on refraction.

๐Ÿ”— List of assets owned by The Walt Disney Company

๐Ÿ”— Companies ๐Ÿ”— Lists ๐Ÿ”— Disney

The following is a list of assets owned and operated by The Walt Disney Company, unless otherwise indicated.

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๐Ÿ”— Dogecoin not notable

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๐Ÿ”— SWEET16: Interpreted byte-code instruction set invented by Steve Wozniak

๐Ÿ”— Apple Inc.

SWEET16 is an interpreted byte-code instruction set invented by Steve Wozniak and implemented as part of the Integer BASIC ROM in the Apple II series of computers. It was created because Wozniak needed to manipulate 16-bit pointer data, and the Apple II was an 8-bit computer.

SWEET16 was not used by the core BASIC code, but was later used to implement several utilities. Notable among these was the line renumbering routine, which was included in the Programmer's Aid #1 ROM, added to later Apple II models and available for user installation on earlier examples.

SWEET16 code is executed as if it were running on a 16-bit processor with sixteen internal 16-bit little-endian registers, named R0 through R15. Some registers have well-defined functions:

  • R0ย โ€“ accumulator
  • R12ย โ€“ subroutine stack pointer
  • R13ย โ€“ stores the result of all comparison operations for branch testing
  • R14ย โ€“ status register
  • R15ย โ€“ program counter

The 16 virtual registers, 32 bytes in total, are located in the zero page of the Apple II's real, physical memory map (at $00โ€“$1F), with values stored as low byte followed by high byte. The SWEET16 interpreter itself is located from $F689 to $F7FC in the Integer BASIC ROM.

According to Wozniak, the SWEET16 implementation is a model of frugal coding, taking up only about 300 bytes in memory. SWEET16 runs at about one-tenth the speed of the equivalent native 6502 code.

๐Ÿ”— Aphantasia

๐Ÿ”— Medicine ๐Ÿ”— Psychology ๐Ÿ”— Disability ๐Ÿ”— Neuroscience

Aphantasia is a condition where one does not possess a functioning mind's eye and cannot voluntarily visualize imagery. The phenomenon was first described by Francis Galton in 1880 but has since remained largely unstudied. Interest in the phenomenon renewed after the publication of a study in 2015 conducted by a team led by Professor Adam Zeman of the University of Exeter, which also coined the term aphantasia. Research on the condition is still scarce.

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๐Ÿ”— PGPfone (1995)

๐Ÿ”— Cryptography ๐Ÿ”— Cryptography/Computer science

PGPfone was a secure voice telephony system developed by Philip Zimmermann in 1995. The PGPfone protocol had little in common with Zimmermann's popular PGP email encryption package, except for the use of the name. It used ephemeral Diffie-Hellman protocol to establish a session key, which was then used to encrypt the stream of voice packets. The two parties compared a short authentication string to detect a Man-in-the-middle attack, which is the most common method of wiretapping secure phones of this type. PGPfone could be used point-to-point (with two modems) over the public switched telephone network, or over the Internet as an early Voice over IP system.

In 1996, there were no protocol standards for Voice over IP. Ten years later, Zimmermann released the successor to PGPfone, Zfone and ZRTP, a newer and secure VoIP protocol based on modern VoIP standards. Zfone builds on the ideas of PGPfone.

According to the MIT PGPfone web page, "MIT is no longer distributing PGPfone. Given that the software has not been maintained since 1997, we doubt it would run on most modern systems."

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๐Ÿ”— Extreme Programming

๐Ÿ”— Computing ๐Ÿ”— Systems ๐Ÿ”— Systems/Software engineering ๐Ÿ”— Method engineering

Extreme programming (XP) is a software development methodology intended to improve software quality and responsiveness to changing customer requirements. As a type of agile software development, it advocates frequent releases in short development cycles, intended to improve productivity and introduce checkpoints at which new customer requirements can be adopted.

Other elements of extreme programming include programming in pairs or doing extensive code review, unit testing of all code, not programming features until they are actually needed, a flat management structure, code simplicity and clarity, expecting changes in the customer's requirements as time passes and the problem is better understood, and frequent communication with the customer and among programmers. The methodology takes its name from the idea that the beneficial elements of traditional software engineering practices are taken to "extreme" levels. As an example, code reviews are considered a beneficial practice; taken to the extreme, code can be reviewed continuously (i.e. the practice of pair programming).

๐Ÿ”— Pizza in North Korea

๐Ÿ”— Korea ๐Ÿ”— Food and drink ๐Ÿ”— Korea/North Korea

North Korea has several restaurants serving pizza. Most people in the country cannot afford pizza, and it is mostly available for the elite. Pyongyang has five restaurants that serve pizza, including Pizza Restaurant on Kwangbok Street and Italy Pizza on Mirae Scientists Street. Kim Jong Il hired Italian chefs to train North Koreans in pizza making and introduced it to the country.

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