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🔗 Computing

Excess-3, 3-excess or 10-excess-3 binary code (often abbreviated as XS-3, 3XS or X3), shifted binary or Stibitz code (after George Stibitz, who built a relay-based adding machine in 1937) is a self-complementary binary-coded decimal (BCD) code and numeral system. It is a biased representation. Excess-3 code was used on some older computers as well as in cash registers and hand-held portable electronic calculators of the 1970s, among other uses.

🔗 Computing 🔗 Computing/Software

86-DOS is a discontinued operating system developed and marketed by Seattle Computer Products (SCP) for its Intel 8086-based computer kit. Initially known as QDOS (Quick and Dirty Operating System), the name was changed to 86-DOS once SCP started licensing the operating system in 1980.

86-DOS had a command structure and application programming interface that imitated that of Digital Research's CP/M operating system, which made it easy to port programs from the latter. The system was licensed and then purchased by Microsoft and developed further as MS-DOS and PC DOS.

🔗 Aviation 🔗 Project-independent assessment

$100 hamburger ("hundred-dollar hamburger") is aviation slang for the excuse a general aviation pilot might use to fly.

🔗 France 🔗 Military history 🔗 British Empire 🔗 Military history/French military history 🔗 Military history/Cold War 🔗 Colonialism 🔗 Egypt 🔗 Israel 🔗 Palestine 🔗 Military history/Middle Eastern military history 🔗 Military history/European military history 🔗 Military history/British military history

The Suez Crisis or the Second Arab–Israeli War, also referred to as the Tripartite Aggression in the Arab world and as the Sinai War in Israel, was a British–French–Israeli invasion of Egypt in 1956. Israel invaded on 29 October, having done so with the primary objective of re-opening the Straits of Tiran and the Gulf of Aqaba as the recent tightening of the eight-year-long Egyptian blockade further prevented Israeli passage. After issuing a joint ultimatum for a ceasefire, the United Kingdom and France joined the Israelis on 5 November, seeking to depose Egyptian president Gamal Abdel Nasser and regain control of the Suez Canal, which Nasser had earlier nationalised by transferring administrative control from the foreign-owned Suez Canal Company to Egypt's new government-owned Suez Canal Authority. Shortly after the invasion began, the three countries came under heavy political pressure from both the United States and the Soviet Union, as well as from the United Nations, eventually prompting their withdrawal from Egypt. Israel's four-month-long occupation of the Egyptian-occupied Gaza Strip and Egypt's Sinai Peninsula enabled it to attain freedom of navigation through the Straits of Tiran, but the Suez Canal itself was closed from October 1956 to March 1957. The Suez Crisis led to international humiliation for the British and the French in the wake of the Cold War, which established the Americans and the Soviets as the world's superpowers. It also strengthened Nasser's standing.

Before they were defeated, Egyptian troops had blocked all ship traffic by sinking 40 ships in the Suez Canal. It later became clear that Israel, the United Kingdom, and France had conspired to invade Egypt. Though the three allies had attained a number of their military objectives, the Suez Canal itself was useless. American president Dwight D. Eisenhower had issued a strong warning to the British if they were to invade Egypt; he threatened serious damage to the British financial system by selling the American government's bonds of pound sterling. Historians have concluded that the Suez Crisis "signified the end of Great Britain's role as one of the world's major powers" vis-à-vis the United States and the Soviet Union.

As a result of the conflict, the United Nations established the United Nations Emergency Force to police and patrol the Egypt–Israel border, while British prime minister Anthony Eden resigned from his position. For his diplomatic efforts in resolving the conflict through United Nations initiatives, Canadian external affairs minister Lester B. Pearson received a Nobel Peace Prize. Analysts have argued that the Suez Crisis may have emboldened the Soviet Union, prompting the Soviet invasion of Hungary.

🔗 Computing 🔗 Electronics 🔗 Electrical engineering

Charlieplexing (also known as tristate multiplexing, reduced pin-count LED multiplexing, complementary LED drive and crossplexing) is a technique for accessing a large number of LEDs, switches, micro-capacitors or other I/O entities, using very few tri-state logic wires from a microcontroller, these entities being wired as discrete components, x/y arrays, or woven in a diagonally intersecting pattern to form diagonal arrays.

The method uses the tri-state logic capabilities of microcontrollers in order to gain efficiency over traditional multiplexing, each I/O pin being capable, when required, of rapidly changing between the three states, logical 1, logical 0, and high impedance.

This enables these I/O entities (LEDs, switches etc.) to be connected between any two microcontroller I/Os - e.g. with 4 I/Os, each I/O can pair with 3 other I/Os, resulting in 6 unique pairings (1/2, 1/3, 1/4, 2/3, 2/4, 3/4). Only 4 pairings are possible with standard x/y multiplexing (1/3, 1/4, 2/3, 2/4). Also, due to the microcontroller's ability to reverse the polarity of the 6 I/O pairs, the number of LEDS (or diodes) that are uniquely addressable, can be doubled to 12 - adding LEDS 2/1, 3/1, 4/1, 3/2, 4/2 and 4/3.

Although it is more efficient in its use of I/O, a small amount of address manipulation is required when trying to fit Charlieplexing into a standard x/y array.

Other issues that affect standard multiplexing but are exacerbated by Charlieplexing are:

• consideration of current requirements and the forward voltages of the LEDs.
• a requirement to cycle through the in-use LEDs rapidly so that the persistence of the human eye perceives the display to be lit as a whole. Multiplexing can generally be seen by a strobing effect and skewing if the eye's focal point is moved past the display rapidly.

🔗 Computing

Modelica is an object-oriented, declarative, multi-domain modeling language for component-oriented modeling of complex systems, e.g., systems containing mechanical, electrical, electronic, hydraulic, thermal, control, electric power or process-oriented subcomponents. The free Modelica language is developed by the non-profit Modelica Association. The Modelica Association also develops the free Modelica Standard Library that contains about 1360 generic model components and 1280 functions in various domains, as of version 3.2.1.

🔗 Games

Nim is a mathematical game of strategy in which two players take turns removing (or "nimming") objects from distinct heaps or piles. On each turn, a player must remove at least one object, and may remove any number of objects provided they all come from the same heap or pile. Depending on the version being played, the goal of the game is either to avoid taking the last object, or to take the last object.

Variants of Nim have been played since ancient times. The game is said to have originated in China—it closely resembles the Chinese game of 捡石子 jiǎn-shízi, or "picking stones"—but the origin is uncertain; the earliest European references to Nim are from the beginning of the 16th century. Its current name was coined by Charles L. Bouton of Harvard University, who also developed the complete theory of the game in 1901, but the origins of the name were never fully explained.

Nim is typically played as a misère game, in which the player to take the last object loses. Nim can also be played as a normal play game, where the player taking the last object wins. This is called normal play because the last move is a winning move in most games, even though it is not the normal way that Nim is played. In either normal play or a misère game, when the number of heaps with at least two objects is exactly equal to one, the next player who takes next can easily win. If this removes either all or all but one objects from the heap that has two or more, then no heaps will have more than one object, so the players are forced to alternate removing exactly one object until the game ends. If the player leaves an even number of non-zero heaps (as the player would do in normal play), the player takes last; if the player leaves an odd number of heaps (as the player would do in misère play), then the other player takes last.

Normal play Nim (or more precisely the system of nimbers) is fundamental to the Sprague–Grundy theorem, which essentially says that in normal play every impartial game is equivalent to a Nim heap that yields the same outcome when played in parallel with other normal play impartial games (see disjunctive sum).

While all normal play impartial games can be assigned a Nim value, that is not the case under the misère convention. Only tame games can be played using the same strategy as misère Nim.

Nim is a special case of a poset game where the poset consists of disjoint chains (the heaps).

The evolution graph of the game of Nim with three heaps is the same as three branches of the evolution graph of the Ulam-Warburton automaton.

At the 1940 New York World's Fair Westinghouse displayed a machine, the Nimatron, that played Nim. From May 11, 1940 to October 27, 1940 only a few people were able to beat the machine in that six week period; if they did they were presented with a coin that said Nim Champ. It was also one of the first ever electronic computerized games. Ferranti built a Nim playing computer which was displayed at the Festival of Britain in 1951. In 1952 Herbert Koppel, Eugene Grant and Howard Bailer, engineers from the W. L. Maxon Corporation, developed a machine weighing 23 kilograms (50 lb) which played Nim against a human opponent and regularly won. A Nim Playing Machine has been described made from TinkerToy.

The game of Nim was the subject of Martin Gardner's February 1958 Mathematical Games column in Scientific American. A version of Nim is played—and has symbolic importance—in the French New Wave film Last Year at Marienbad (1961).

🔗 Religion 🔗 Classical Greece and Rome 🔗 Middle Ages 🔗 Middle Ages/History 🔗 Cryptography 🔗 Cryptography/Computer science 🔗 Latin 🔗 Christianity 🔗 Jewish history 🔗 Occult 🔗 Mysticism

The Sator Square (or Rotas Square) is a word square containing a five-word Latin palindrome. The earliest form has ROTAS as the top line, but in time the version with SATOR on the top line became dominant. It is a 5X5 square made up of five 5-letter words, thus consisting of 25 letters in total. These 25 letters are all derived from 8 Latin letters: 5 consonants (S, T, R, P, N) and 3 vowels (A, E, O).

In particular, this is a square 2D palindrome, which is when a square text admits four symmetries: identity, two diagonal reflections, and 180 degree rotation. As can be seen, the text may be read top-to-bottom, bottom-to-top, left-to-right, or right-to-left; and it may be rotated 180 degrees and still be read in all those ways.

The Sator Square is the earliest dateable 2D palindrome. It was found in the ruins of Pompeii, at Herculaneum, a city buried in the ash of Mount Vesuvius in 79 AD. It consists of a sentence written in Latin: "Sator Arepo Tenet Opera Rotas." Its translation has been the subject of speculation with no clear consensus; see below for details.

Other 2D Palindrome examples may be found carved on stone tablets or pressed into clay before being fired.

🔗 United States 🔗 Trains 🔗 United States/Ohio 🔗 Trains/Rapid transit 🔗 United States/Cincinnati

The Cincinnati Subway is a set of incomplete, derelict tunnels and stations for a rapid transit system beneath the streets of Cincinnati, Ohio. Although it is only a little over 2 miles in length, it is the largest abandoned subway tunnel system in the United States. Construction began in the early 1900s as an upgrade to the Cincinnati streetcar system, but was abandoned due to escalating costs, the collapse of funding amidst political bickering, and the Great Depression during the 1920s and 1930s.

In 1928, the construction of the subway system in Cincinnati was indefinitely canceled. There are no plans to revive the project.

🔗 England 🔗 Linguistics

The Great Vowel Shift was a series of changes in the pronunciation of the English language that took place primarily between 1400 and 1700, beginning in southern England and today having influenced effectively all dialects of English. Through this vowel shift, the pronunciation of all Middle English long vowels was changed. Some consonant sounds changed as well, particularly those that became silent; the term Great Vowel Shift is sometimes used to include these consonant changes.

English spelling began to become standardized in the 15th and 16th centuries, and the Great Vowel Shift is the major reason English spellings now often considerably deviate from how they represent pronunciations. The Great Vowel Shift was first studied by Otto Jespersen (1860–1943), a Danish linguist and Anglicist, who coined the term.