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🔗 Luhn Algorithm for validating credit cards

🔗 Computing 🔗 Mathematics

The Luhn algorithm or Luhn formula, also known as the "modulus 10" or "mod 10" algorithm, named after its creator, IBM scientist Hans Peter Luhn, is a simple checksum formula used to validate a variety of identification numbers, such as credit card numbers, IMEI numbers, National Provider Identifier numbers in the United States, Canadian Social Insurance Numbers, Israel ID Numbers, South African ID Numbers, Greek Social Security Numbers (ΑΜΚΑ), and survey codes appearing on McDonald's, Taco Bell, and Tractor Supply Co. receipts. It is described in U.S. Patent No. 2,950,048, filed on January 6, 1954, and granted on August 23, 1960.

The algorithm is in the public domain and is in wide use today. It is specified in ISO/IEC 7812-1. It is not intended to be a cryptographically secure hash function; it was designed to protect against accidental errors, not malicious attacks. Most credit cards and many government identification numbers use the algorithm as a simple method of distinguishing valid numbers from mistyped or otherwise incorrect numbers.

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🔗 Men Without Work: America's Invisible Crisis (Book)

🔗 Economics 🔗 Books

Men Without Work: America's Invisible Crisis is a 2016 book by the American political economist Nicholas Eberstadt discussing the phenomenon of American men in their prime leaving the workforce. Statistically, the labor force involvement for men twenty and older fell from 86% to 68% between 1948 and 2015. The book discusses the history, causes, and implications of the phenomenon, as well as possible solutions.

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🔗 FE-Schrift

🔗 Germany 🔗 Law Enforcement 🔗 Typography

The FE-Schrift or Fälschungserschwerende Schrift (forgery-impeding typeface) is a sans serif typeface introduced for use on licence plates. Its monospaced letters and numbers are slightly disproportionate to prevent easy modification and to improve machine readability. It has been developed in Germany where it has been mandatory since November 2000.

The abbreviation "FE" is derived from the compound German adjective "fälschungserschwerend" combining the noun "Fälschung" (falsification) and the verb "erschweren" (to hinder). "Schrift" means font in German. Other countries have later introduced the same or a derived typeface for license plates taking advantage of the proven design for the FE-Schrift.

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🔗 MIPS R3000

🔗 Computing

The R3000 is a 32-bit RISC microprocessor chipset developed by MIPS Computer Systems that implemented the MIPS I instruction set architecture (ISA). Introduced in June 1988, it was the second MIPS implementation, succeeding the R2000 as the flagship MIPS microprocessor. It operated at 20, 25 and 33.33 MHz.

The MIPS 1 instruction set is small compared to those of the contemporary 80x86 and 680x0 architectures, encoding only more commonly used operations and supporting few addressing modes. Combined with its fixed instruction length and only three different types of instruction formats, this simplified instruction decoding and processing. It employed a 5-stage instruction pipeline, enabling execution at a rate approaching one instruction per cycle, unusual for its time.

This MIPS generation supports up to four co-processors. In addition to the CPU core, the R3000 microprocessor includes a Control Processor (CP), which contains a Translation Lookaside Buffer and a Memory Management Unit. The CP works as a coprocessor. Besides the CP, the R3000 can also support an external R3010 numeric coprocessor and two other external coprocessors.

The R3000 CPU does not include level 1 cache. Instead, its on-chip cache controller operates external data and instruction caches of up to 256 KB each. It can access both caches during the same clock cycle.

The R3000 found much success and was used by many companies in their workstations and servers. Users included:

  • Ardent Computer
  • Digital Equipment Corporation (DEC) for their DECstation workstations and multiprocessor DECsystem servers
  • Evans & Sutherland for their Vision (ESV) series workstations
  • MIPS Computer Systems for their MIPS RISC/os Unix workstations and servers.
  • NEC for their RISC EWS4800 workstations and UP4800 servers.
  • Prime Computer
  • Pyramid Technology
  • Seiko Epson
  • Silicon Graphics for their Professional IRIS, Personal IRIS and Indigo workstations, and the multiprocessor Power Series visualization systems
  • Sony for their PlayStation and PlayStation 2 (SCPH-10000 to SCPH-700XX - clocked at 37.5 MHz for use as an I/O CPU and at 33.8 MHz for compatibility with PlayStation games) video game consoles, and NEWS workstations, as well as the Bemani System 573 Analog arcade unit, which runs on the R3000A.
  • Tandem Computers for their NonStop Cyclone/R and CLX/R fault-tolerant servers
  • Whitechapel Workstations for their Hitech-20 workstation
  • New Horizons Probe

The R3000 was also used as an embedded microprocessor. When advances in technology rendered it obsolete for high-performance systems, it found continued use in lower-cost designs. Companies such as LSI Logic developed derivatives of the R3000 specifically for embedded systems.

The R3000 was a further development of the R2000 with minor improvements including larger TLB and a faster bus to the external caches. The R3000 die contained 115,000 transistors and measured about 75,000 square mils (48 mm2). MIPS was a fabless semiconductor company, so the R3000 was fabricated by MIPS partners including Integrated Device Technology (IDT), LSI Logic, NEC Corporation, Performance Semiconductor, and others. It was fabricated in a 1.2 μm complementary metal–oxide–semiconductor (CMOS) process with two levels of aluminium interconnect.

Derivatives of the R3000 for non-embedded applications include:

  • R3000A - A further development by MIPS introduced in 1989. It operated at clock frequencies up to 40 MHz.
  • PR3400 - Developed by Performance Semiconductor, introduced in May 1991, also at up to 40 MHz. It integrated the Performance Semiconductor PR3000A and PR3010A onto a single die.

Derivatives of the R3000 for embedded applications include:

  • PR31700 - A 75 MHz microcontroller from Philips Semiconductors. Fabricated in a 0.35 μm process, delivered in a 208-pin LQFP, it operated at 3.3 V and dissipated only 0.35 W.
  • RISController - A family of low-end microcontrollers from IDT. Models include the R3041, R3051, R3052, and R3081.
  • TX3900 - A microcontroller from Toshiba.
  • Mongoose-V - A radiation-hardened and expanded 10–15 MHz CPU for use on spacecraft, it is still in use today in applications such as NASA's New Horizons space probe.

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🔗 List of people named in the Panama Papers

🔗 Biography 🔗 International relations 🔗 Crime 🔗 Finance & Investment 🔗 Politics 🔗 Journalism 🔗 Panama

This is a partial list of people named in the Panama Papers as shareholders, directors and beneficiaries of offshore companies. The International Consortium of Investigative Journalists (ICIJ) released the full list of companies and individuals in the Panama Papers on 10 May 2016. ICIJ published the following disclaimer with regard to the data provided: "There are legitimate uses for offshore companies, foundations and trusts. We do not intend to suggest or imply that any persons, companies or other entities included in the ICIJ Power Players interactive application have broken the law or otherwise acted improperly."

🔗 Charrette

🔗 Architecture 🔗 Urban studies and planning

A charrette (American pronunciation: ), often Anglicized to charette or charet and sometimes called a design charrette, is an intense period of design or planning activity.

The word charrette may refer to any collaborative session in which a group of designers draft a solution to a design problem.

While the structure of a charrette varies, depending on the design problem and the individuals in the group, charrettes often take place in multiple sessions in which the group divides into sub-groups. Each sub-group then presents its work to the full group as material for further dialogue. Such charrettes serve as a way of quickly generating a design solution while integrating the aptitudes and interests of a diverse group of people. The general idea of a charrette is to create an innovative atmosphere in which a diverse group of stakeholders can collaborate to "generate visions for the future".

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🔗 Mode X

🔗 Computing

Mode X is an alternative graphics display mode of the IBM VGA graphics hardware that was popularized by Michael Abrash. It was first published in July 1991 in Dr. Dobb's Journal, and republished in chapters 47-49 of Abrash's Graphics Programming Black Book (now freely available online). The term "Mode X" was coined by Abrash.

The primary advantage of Mode X is that it has square pixels: a resolution of 320×240 instead of the standard VGA Mode 13h which is 320×200. Additionally, Abrash enabled the VGA's planar memory mode (also called "unchained mode"). Even though planar memory mode is a documented part of the VGA standard and was used in earlier commercial games, it was first widely publicized in the Mode X articles, leading many programmers to consider Mode X and planar memory synonymous. It is possible to enable planar memory in standard 320x200 mode, which became known as Mode Y in the Usenet rec.games.programmer group.

Planar memory arrangement splits the pixels horizontally into groups of four. For any given byte in PC video memory, four pixels on screen can be accessed depending on which plane(s) are enabled. This is more complicated for the programmer, but the advantages gained by this arrangement—primarily the ability to use all 256 KB of VGA memory for one or more display buffers, instead of only one quarter of that (64 KB)—were considered worthwhile by many.

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🔗 Nominative determinism

🔗 Business 🔗 Psychology 🔗 Languages 🔗 Anthroponymy

Nominative determinism is the hypothesis that people tend to gravitate towards areas of work that fit their names. The term was first used in the magazine New Scientist in 1994, after the magazine's humorous Feedback column noted several studies carried out by researchers with remarkably fitting surnames. These included a book on polar explorations by Daniel Snowman and an article on urology by researchers named Splatt and Weedon. These and other examples led to light-hearted speculation that some sort of psychological effect was at work. Since the term appeared, nominative determinism has been an irregularly recurring topic in New Scientist, as readers continue to submit examples. Nominative determinism differs from the related concept aptronym, and its synonyms aptonym, namephreak, and Perfect Fit Last Name, in that it focuses on causality. "Aptronym" merely means the name is fitting, without saying anything about why it has come to fit.

The idea that people are drawn to professions that fit their name was suggested by psychologist Carl Jung, citing as an example Sigmund Freud who studied pleasure and whose surname means "joy". A few recent empirical studies have indicated that certain professions are disproportionately represented by people with appropriate surnames (and sometimes given names), though the methods of these studies have been challenged. One explanation for nominative determinism is implicit egotism, which states that humans have an unconscious preference for things they associate with themselves. An alternative explanation is genetic: a person might be named Smith or Taylor because that was originally their occupation, and they would pass on their genes to their descendants, including an aptitude for activities involving strength in the case of Smith, or dexterity in the case of Taylor.

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🔗 Konstantin Tsiolkovsky

🔗 Biography 🔗 Soviet Union 🔗 Russia 🔗 Russia/technology and engineering in Russia 🔗 Spaceflight 🔗 Biography/science and academia 🔗 Transhumanism 🔗 Russia/science and education in Russia 🔗 Biography/arts and entertainment 🔗 Rocketry

Konstantin Eduardovich Tsiolkovsky (Russian: Константи́н Эдуа́рдович Циолко́вский; 17 September [O.S. 5 September] 1857 – 19 September 1935) was a Russian and Soviet rocket scientist who pioneered astronautics. Along with the Frenchman Robert Esnault-Pelterie, the Germans Hermann Oberth and Fritz von Opel, and the American Robert H. Goddard, he is one of the founding fathers of modern rocketry and astronautics. His works later inspired leading Soviet rocket-engineers Sergei Korolev and Valentin Glushko, who contributed to the success of the Soviet space program.

Tsiolkovsky spent most of his life in a log house on the outskirts of Kaluga, about 200 km (120 mi) southwest of Moscow. A recluse by nature, his unusual habits made him seem bizarre to his fellow townsfolk.

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🔗 Netherlandish Proverbs (1559)

🔗 Visual arts 🔗 Belgium

Netherlandish Proverbs (Dutch: Nederlandse Spreekwoorden; also called Flemish Proverbs, The Blue Cloak or The Topsy Turvy World) is a 1559 oil-on-oak-panel painting by Pieter Bruegel the Elder that depicts a scene in which humans and, to a lesser extent, animals and objects, offer literal illustrations of Dutch-language proverbs and idioms.

Running themes in Bruegel's paintings are the absurdity, wickedness and foolishness of humans, and this is no exception. The painting's original title, The Blue Cloak or The Folly of the World, indicates that Bruegel's intent was not just to illustrate proverbs, but rather to catalog human folly. Many of the people depicted show the characteristic blank features that Bruegel used to portray fools.

His son, Pieter Brueghel the Younger, specialised in making copies of his father's work and painted at least 16 copies of Netherlandish Proverbs. Not all versions of the painting, by father or son, show exactly the same proverbs and they also differ in other minor details.

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