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🔗 Science Fiction

"Computers Don't Argue" is a 1965 science fiction short story by American writer Gordon R. Dickson, about the dangers of relying too strongly upon computers. It was nominated for a Nebula Award in 1966.

🔗 Biography 🔗 Russia 🔗 Russia/technology and engineering in Russia 🔗 Russia/demographics and ethnography of Russia 🔗 African diaspora 🔗 Russia/Russian, Soviet, and CIS military history 🔗 Russia/history of Russia

Abram Petrovich Gannibal, also Hannibal or Ganibal, or Abram Hannibal or Abram Petrov (Russian: Абра́м Петро́вич Ганниба́л; c. 1696 – 14 May 1781), was a Russian military engineer, major-general, and nobleman of African origin. Kidnapped as a child, Gannibal was taken to Russia and presented as a gift to Peter the Great, where he was freed, adopted and raised in the Emperor's court household as his godson.

Gannibal eventually rose to become a prominent member of the imperial court in the reign of Peter's daughter Elizabeth. He had 11 children, most of whom became members of the Russian nobility; he was a great-grandfather of the author and poet Alexander Pushkin.

🔗 Philosophy 🔗 Philosophy/Philosophical literature 🔗 Books 🔗 Philosophy/Modern philosophy 🔗 Japan 🔗 Philosophy/Eastern philosophy

The "Dokkōdō" (Japanese: 獨行道) ("The Path of Aloneness", "The Way to Go Forth Alone", or "The Way of Walking Alone"), is a short work written by Miyamoto Musashi a week before he died in 1645. It consists of 21 precepts. "Dokkodo" was largely composed on the occasion of Musashi giving away his possessions in preparation for death, and was dedicated to his favorite disciple, Terao Magonojō (to whom the earlier Go rin no sho [The Book of Five Rings] had also been dedicated), who took them to heart. "Dokkōdō" expresses a stringent, honest, and ascetic view of life.

The 21 precepts of Dokkodo:

1. Accept everything just the way it is.

2. Do not seek pleasure for its own sake.

3. Do not, under any circumstances, depend on a partial feeling.

4. Think lightly of yourself and deeply of the world.

5. Be detached from desire your whole life long.

6. Do not regret what you have done.

7. Never be jealous.

8. Never let yourself be saddened by a separation.

9. Resentment and complaint are appropriate neither for oneself or others.

10. Do not let yourself be guided by the feeling of lust or love.

11. In all things have no preferences.

12. Be indifferent to where you live.

13. Do not pursue the taste of good food.

14. Do not hold on to possessions you no longer need.

15. Do not act following customary beliefs.

16. Do not collect weapons or practice with weapons beyond what is useful.

17. Do not fear death.

18. Do not seek to possess either goods or fiefs for your old age.

19. Respect Buddha and the gods without counting on their help.

20. You may abandon your own body but you must preserve your honour.

21. Never stray from the Way.

🔗 Biography 🔗 Biography/science and academia 🔗 Israel

Abraham Lempel (Hebrew: אברהם למפל, 10 February 1936 – 4 February 2023) was an Israeli computer scientist and one of the fathers of the LZ family of lossless data compression algorithms.

🔗 United Kingdom 🔗 Classical music 🔗 Classical music/Compositions

Edward Elgar composed his Variations on an Original Theme, Op. 36, popularly known as the Enigma Variations, between October 1898 and February 1899. It is an orchestral work comprising fourteen variations on an original theme.

Elgar dedicated the work "to my friends pictured within", each variation being a musical sketch of one of his circle of close acquaintances (see musical cryptogram). Those portrayed include Elgar's wife Alice, his friend and publisher Augustus J. Jaeger and Elgar himself. In a programme note for a performance in 1911 Elgar wrote:

This work, commenced in a spirit of humour & continued in deep seriousness, contains sketches of the composer's friends. It may be understood that these personages comment or reflect on the original theme & each one attempts a solution of the Enigma, for so the theme is called. The sketches are not 'portraits' but each variation contains a distinct idea founded on some particular personality or perhaps on some incident known only to two people. This is the basis of the composition, but the work may be listened to as a 'piece of music' apart from any extraneous consideration.

In naming his theme "Enigma", Elgar posed a challenge which has generated much speculation but has never been conclusively answered. The Enigma is widely believed to involve a hidden melody.

After its 1899 London premiere the Variations achieved immediate popularity and established Elgar's international reputation.

🔗 Time

Segal's law is an adage that states:

A man with a watch knows what time it is. A man with two watches is never sure.

At surface level, the adage emphasizes the consistency that arises when information comes from a single source and points out the potential pitfalls of having too much conflicting information. However, the underlying message is to question the apparent certainty of anyone who only has one source of information. The man with one watch has no way to identify error or uncertainty.

🔗 Mathematics

Wikipedia provides one of the more prominent resources on the Web for factual information about contemporary mathematics, with over 20,000 articles on mathematical topics. It is natural that many readers use Wikipedia for the purpose of self-study in mathematics and its applications. Some readers will be simultaneously studying mathematics in a more formal way, while others will rely on Wikipedia alone. There are certain points that need to be kept in mind by anyone using Wikipedia for mathematical self-study, in order to make the best use of what is here, perhaps in conjunction with other resources.

🔗 Religion 🔗 Africa 🔗 Ancient Egypt 🔗 Mythology 🔗 Africa/Ancient Egypt

In Ancient Egyptian religion, Medjed is a minor and obscure god mentioned in the Book of the Dead. His ghost-like portrayal in illustrations on the Greenfield papyrus earned him popularity in modern Japanese culture, including as a character in video games and anime.

🔗 Biography 🔗 Mathematics 🔗 Environment 🔗 Iran 🔗 Biography/science and academia 🔗 Astronomy 🔗 Geography 🔗 History of Science 🔗 Astrology 🔗 Middle Ages 🔗 Islam 🔗 Middle Ages/History 🔗 Central Asia 🔗 Maps 🔗 Iraq 🔗 Biography/Core biographies 🔗 Islam/Muslim scholars

Muḥammad ibn Mūsā al-Khwārizmī (Persian: Muḥammad Khwārizmī محمد بن موسی خوارزمی‎; c. 780 – c. 850), Arabized as al-Khwarizmi with al- and formerly Latinized as Algorithmi, was a Persian polymath who produced works in mathematics, astronomy, and geography. Around 820 CE he was appointed as the astronomer and head of the library of the House of Wisdom in Baghdad.

Al-Khwarizmi's popularizing treatise on algebra (The Compendious Book on Calculation by Completion and Balancing, c. 813–833 CE) presented the first systematic solution of linear and quadratic equations. One of his principal achievements in algebra was his demonstration of how to solve quadratic equations by completing the square, for which he provided geometric justifications. Because he was the first to treat algebra as an independent discipline and introduced the methods of "reduction" and "balancing" (the transposition of subtracted terms to the other side of an equation, that is, the cancellation of like terms on opposite sides of the equation), he has been described as the father or founder of algebra. The term algebra itself comes from the title of his book (specifically the word al-jabr meaning "completion" or "rejoining"). His name gave rise to the terms algorism and algorithm. His name is also the origin of (Spanish) guarismo and of (Portuguese) algarismo, both meaning digit.

In the 12th century, Latin translations of his textbook on arithmetic (Algorithmo de Numero Indorum) which codified the various Indian numerals, introduced the decimal positional number system to the Western world. The Compendious Book on Calculation by Completion and Balancing, translated into Latin by Robert of Chester in 1145, was used until the sixteenth century as the principal mathematical text-book of European universities.

In addition to his best-known works, he revised Ptolemy's Geography, listing the longitudes and latitudes of various cities and localities. He further produced a set of astronomical tables and wrote about calendaric works, as well as the astrolabe and the sundial. He also made important contributions to trigonometry, producing accurate sine and cosine tables, and the first table of tangents.

🔗 Computing 🔗 Mathematics

A nomogram (from Greek νόμος nomos, "law" and γραμμή grammē, "line"), also called a nomograph, alignment chart, or abaque, is a graphical calculating device, a two-dimensional diagram designed to allow the approximate graphical computation of a mathematical function. The field of nomography was invented in 1884 by the French engineer Philbert Maurice d'Ocagne (1862–1938) and used extensively for many years to provide engineers with fast graphical calculations of complicated formulas to a practical precision. Nomograms use a parallel coordinate system invented by d'Ocagne rather than standard Cartesian coordinates.

A nomogram consists of a set of n scales, one for each variable in an equation. Knowing the values of n-1 variables, the value of the unknown variable can be found, or by fixing the values of some variables, the relationship between the unfixed ones can be studied. The result is obtained by laying a straightedge across the known values on the scales and reading the unknown value from where it crosses the scale for that variable. The virtual or drawn line created by the straightedge is called an index line or isopleth.

Nomograms flourished in many different contexts for roughly 75 years because they allowed quick and accurate computations before the age of pocket calculators. Results from a nomogram are obtained very quickly and reliably by simply drawing one or more lines. The user does not have to know how to solve algebraic equations, look up data in tables, use a slide rule, or substitute numbers into equations to obtain results. The user does not even need to know the underlying equation the nomogram represents. In addition, nomograms naturally incorporate implicit or explicit domain knowledge into their design. For example, to create larger nomograms for greater accuracy the nomographer usually includes only scale ranges that are reasonable and of interest to the problem. Many nomograms include other useful markings such as reference labels and colored regions. All of these provide useful guideposts to the user.

Like a slide rule, a nomogram is a graphical analog computation device, and like the slide rule, its accuracy is limited by the precision with which physical markings can be drawn, reproduced, viewed, and aligned. While the slide rule is intended to be a general-purpose device, a nomogram is designed to perform a specific calculation, with tables of values effectively built into the construction of the scales. Nomograms are typically used in applications where the level of accuracy they offer is sufficient and useful. Alternatively, a nomogram can be used to check an answer obtained from another, more exact but possibly error-prone calculation.

Other types of graphical calculators such as intercept charts, trilinear diagrams and hexagonal charts are sometimes called nomograms. Other such examples include the Smith chart, a graphical calculator used in electronics and systems analysis, thermodynamic diagrams and tephigrams, used to plot the vertical structure of the atmosphere and perform calculations on its stability and humidity content. These do not meet the strict definition of a nomogram as a graphical calculator whose solution is found by the use of one or more linear isopleths.