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🔗 Biography 🔗 Biography/science and academia

David J. DeWitt is a computer scientist specializing in database management system research at the Massachusetts Institute of Technology. Prior to moving to MIT, DeWitt was the John P. Morgridge Professor (Emeritus) of Computer Sciences at the University of Wisconsin–Madison. He was also a Technical Fellow at Microsoft, leading the Microsoft Jim Gray Systems Lab at Madison, Wisconsin. Professor DeWitt received a B.A. degree from Colgate University in 1970, and a Ph.D. from the University of Michigan in 1976. He then joined the University of Wisconsin-Madison and started the Wisconsin Database Group, which he led for more than 30 years.

Professor DeWitt is known for his research in the areas of parallel databases, benchmarking, object-oriented databases, and XML databases. He is an elected member of the National Academy of Engineering (1998), and a Fellow of the Association for Computing Machinery.

He received the ACM SIGMOD Innovations Award (now renamed SIGMOD Edgar F. Codd Innovations Award) in 1995 for his contributions to the database systems field. In 2009, ACM recognized the seminal contributions of his Gamma parallel database system project with the ACM Software System Award. Also in 2009, he received the IEEE Emanuel R. Piore Award for his contributions to the database systems field.

🔗 Internet 🔗 Computing 🔗 Finance & Investment 🔗 Economics 🔗 Computing/Software 🔗 Computing/Free and open-source software 🔗 Cryptography 🔗 Cryptography/Computer science 🔗 Numismatics 🔗 Numismatics/Cryptocurrency 🔗 Cryptocurrency

Dogecoin ( DOHJ-koyn, code: DOGE, symbol: Ð) is a cryptocurrency featuring a likeness of the Shiba Inu dog from the "Doge" Internet meme as its logo. Introduced as a "joke currency" on 6 December 2013, Dogecoin quickly developed its own online community and reached a capitalization of US$60 million in January 2014.

Compared with other cryptocurrencies, Dogecoin had a fast initial coin production schedule: 100 billion coins were in circulation by mid-2015, with an additional 5.256 billion coins every year thereafter. As of 30 June 2015, the 100 billionth Dogecoin had been mined. While there are few mainstream commercial applications, the currency has gained traction as an Internet tipping system, in which social media users grant Dogecoin tips to other users for providing interesting or noteworthy content. Dogecoin is referred to as an altcoin.

🔗 United States 🔗 Politics

The political philosopher Sheldon Wolin coined the term inverted totalitarianism in 2003 to describe what he saw as the emerging form of government of the United States. Wolin analysed the United States as increasingly turning into a managed democracy (similar to an illiberal democracy). He uses the term "inverted totalitarianism" to draw attention to the totalitarian aspects of the American political system while emphasizing its differences from proper totalitarianism, such as Nazi and Stalinist regimes.

The book Days of Destruction, Days of Revolt (2012) by Chris Hedges and Joe Sacco portrays inverted totalitarianism as a system where corporations have corrupted and subverted democracy and where economics bests politics. Every natural resource and living being is commodified and exploited by large corporations to the point of collapse as excess consumerism and sensationalism lull and manipulate the citizenry into surrendering their liberties and their participation in government.

🔗 Engineering

The turboencabulator or turbo-encabulator (and its later incarnations, the retroencabulator or retro-encabulator and Micro Encabulator) is a fictional machine whose alleged existence became an in-joke and subject of professional humor among engineers. The explanation of the supposed product makes extensive use of technobabble.

The gag was popular for many years. The following quote is from the original Students' Quarterly Journal article written by J. H. Quick in 1944. The citation in the later Time article misspells several of the technical terms. General Electric, Chrysler and Rockwell Automation use many of the same words.

The original machine had a base plate of prefabulated amulite, surmounted by a malleable logarithmic casing in such a way that the two main spurving bearings were in a direct line with the panametric fan. The latter consisted simply of six hydrocoptic marzlevanes, so fitted to the ambifacient lunar waneshaft that side fumbling was effectively prevented. The main winding was of the normal lotus-o-deltoid type placed in panendermic semi-boloid slots in the stator, every seventh conductor being connected by a nonreversible tremmie pipe to the differential girdlespring on the "up" end of the grammeters.

A shaft passer is a hypothetical device that allows a spoked wheel to rotate despite having a shaft (such as the axle of another wheel) passing between its spokes. The device is usually mentioned as a joke between nerds, in the manner of a fool's errand, since there is no evidence of one ever having been constructed until very recently.

One of the earliest printed references to these devices was made by Richard Feynman, who was told by a colleague at Frankford Arsenal in Philadelphia that the cable-passing version of the device had been used during both world wars on German naval mine mooring cables, to prevent the mines from being caught by British cables swept along the sea bottom.

The device was supposed to work using a spoked, rimless wheel that allows cables to pass through as it rotates. The ends of the spokes are widened, and the cable is held together by a short curved sleeve through which these spoke ends slide.

🔗 Measurement

ISO 1 is an international standard set by the International Organization for Standardization that specifies the standard reference temperature for geometrical product specification and verification. The temperature is fixed at 20 °C, which is equal to 293.15 kelvins and 68 degrees Fahrenheit.

Due to thermal expansion, precision length measurements need to be made at (or converted to) a defined temperature. ISO 1 helps in comparing measurements by defining such a reference temperature. The reference temperature of 20 °C was adopted by the CIPM on 15 April 1931, and became ISO recommendation number 1 in 1951. It soon replaced worldwide other reference temperatures for length measurements that manufacturers of precision equipment had used before, including 0 °C, 62 °F, and 25 °C. Among the reasons for choosing 20 °C was that this was a comfortable and practical workshop temperature and that it resulted in an integer value on both the Celsius and Fahrenheit scales.

🔗 Mathematics

This is a list of mathematical symbols used in all branches of mathematics to express a formula or to represent a constant.

A mathematical concept is independent of the symbol chosen to represent it. For many of the symbols below, the symbol is usually synonymous with the corresponding concept (ultimately an arbitrary choice made as a result of the cumulative history of mathematics), but in some situations, a different convention may be used. For example, depending on context, the triple bar "≡" may represent congruence or a definition. However, in mathematical logic, numerical equality is sometimes represented by "≡" instead of "=", with the latter representing equality of well-formed formulas. In short, convention dictates the meaning.

Each symbol is shown both in HTML, whose display depends on the browser's access to an appropriate font installed on the particular device, and typeset as an image using TeX.

🔗 Mathematics

The ant on a rubber rope is a mathematical puzzle with a solution that appears counterintuitive or paradoxical. It is sometimes given as a worm, or inchworm, on a rubber or elastic band, but the principles of the puzzle remain the same.

The details of the puzzle can vary, but a typical form is as follows:

An ant starts to crawl along a taut rubber rope 1 km long at a speed of 1 cm per second (relative to the rubber it is crawling on). At the same time, the rope starts to stretch uniformly at a constant rate of 1 km per second, so that after 1 second it is 2 km long, after 2 seconds it is 3 km long, etc. Will the ant ever reach the end of the rope?

At first consideration it seems that the ant will never reach the end of the rope, but in fact it does. (In the form stated above, it would take 8.9×10⁴³⁴²¹ years.) Whatever the length of the rope and the relative speeds of the ant and the stretching, provided that the ant's speed and the stretching remain steady, the ant will always be able to reach the end given sufficient time. Once the ant has begun moving, the rubber rope is stretching both in front of and behind the ant, conserving the proportion of the rope already walked by the ant and enabling the ant to make continual progress.

🔗 Finance & Investment 🔗 Economics 🔗 India 🔗 Arab world

Hawala or hewala (Arabic: حِوالة‎ ḥawāla, meaning transfer or sometimes trust), also known as havaleh in Persian, and xawala or xawilaad in Somali, is a popular and informal value transfer system based not on the movement of cash, or on telegraph or computer network wire transfers between banks, but instead on the performance and honour of a huge network of money brokers (known as hawaladars). While hawaladars are spread throughout the world, they are primarily located in the Middle East, North Africa, the Horn of Africa, and the Indian subcontinent, operating outside of, or parallel to, traditional banking, financial channels, and remittance systems. Hawala follows Islamic traditions but its use is not limited to Muslims.

🔗 Computing 🔗 Computing/Computer hardware

PLATO (Programmed Logic for Automatic Teaching Operations) was the first generalized computer-assisted instruction system. Starting in 1960, it ran on the University of Illinois' ILLIAC I computer. By the late 1970s, it supported several thousand graphics terminals distributed worldwide, running on nearly a dozen different networked mainframe computers. Many modern concepts in multi-user computing were originally developed on PLATO, including forums, message boards, online testing, e-mail, chat rooms, picture languages, instant messaging, remote screen sharing, and multiplayer video games.

PLATO was designed and built by the University of Illinois and functioned for four decades, offering coursework (elementary through university) to UIUC students, local schools, and other universities. Courses were taught in a range of subjects, including Latin, chemistry, education, music, and primary mathematics. The system included a number of features useful for pedagogy, including text overlaying graphics, contextual assessment of free-text answers, depending on the inclusion of keywords, and feedback designed to respond to alternative answers.

Rights to market PLATO as a commercial product were licensed by Control Data Corporation (CDC), the manufacturer on whose mainframe computers the PLATO IV system was built. CDC President William Norris planned to make PLATO a force in the computer world, but found that marketing the system was not as easy as hoped. PLATO nevertheless built a strong following in certain markets, and the last production PLATO system did not shut down until 2006, coincidentally just a month after Norris died.