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πŸ”— Dining Cryptographers Problem

πŸ”— Cryptography πŸ”— Cryptography/Computer science

In cryptography, the dining cryptographers problem studies how to perform a secure multi-party computation of the boolean-OR function. David Chaum first proposed this problem in the early 1980s and used it as an illustrative example to show that it was possible to send anonymous messages with unconditional sender and recipient untraceability. Anonymous communication networks based on this problem are often referred to as DC-nets (where DC stands for "dining cryptographers").

Despite the word dining, the dining cryptographers problem is unrelated to the dining philosophers problem.

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πŸ”— Christopher Alexander

πŸ”— Biography πŸ”— Architecture πŸ”— Biography/science and academia πŸ”— Urban studies and planning πŸ”— University of California

Christopher Wolfgang Alexander (born 4 October 1936 in Vienna, Austria) is a widely influential British-American architect and design theorist, and currently emeritus professor at the University of California, Berkeley. His theories about the nature of human-centered design have affected fields beyond architecture, including urban design, software, sociology and others. Alexander has designed and personally built over 100 buildings, both as an architect and a general contractor.

In software, Alexander is regarded as the father of the pattern language movement. The first wikiβ€”the technology behind Wikipediaβ€”led directly from Alexander's work, according to its creator, Ward Cunningham. Alexander's work has also influenced the development of agile software development.

In architecture, Alexander's work is used by a number of different contemporary architectural communities of practice, including the New Urbanist movement, to help people to reclaim control over their own built environment. However, Alexander is controversial among some mainstream architects and critics, in part because his work is often harshly critical of much of contemporary architectural theory and practice.

Alexander is known for many books on the design and building process, including Notes on the Synthesis of Form, A City is Not a Tree (first published as a paper and re-published in book form in 2015), The Timeless Way of Building, A New Theory of Urban Design, and The Oregon Experiment. More recently he published the four-volume The Nature of Order: An Essay on the Art of Building and the Nature of the Universe, about his newer theories of "morphogenetic" processes, and The Battle for the Life and Beauty of the Earth, about the implementation of his theories in a large building project in Japan. All his works are developed or accumulated from his previous works, so his works should be read as a whole rather than fragmented pieces. His life's work or the best of his works is The Nature of Order on which he spent about 30 years, and the very first version of The Nature of Order was done in 1981, one year before this famous debate with Peter Eisenman in Harvard.

Alexander is perhaps best known for his 1977 book A Pattern Language, a perennial seller some four decades after publication. Reasoning that users are more sensitive to their needs than any architect could be, he produced and validated (in collaboration with his students Sara Ishikawa, Murray Silverstein, Max Jacobson, Ingrid King, and Shlomo Angel) a "pattern language" to empower anyone to design and build at any scale.

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πŸ”— Alan L. Hart

πŸ”— Biography πŸ”— Oregon πŸ”— LGBT studies

Alan L. Hart (born Alberta Lucille Hart, October 4, 1890 – July 1, 1962) was an American physician, radiologist, tuberculosis researcher, writer and novelist. He was in 1917–18 one of the first trans men to undergo hysterectomy in the United States, and lived the rest of his life as a man. He pioneered the use of x-ray photography in tuberculosis detection, and helped implement TB screening programs that saved thousands of lives.

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πŸ”— Behavioral Immune System

πŸ”— Psychology

The behavioral immune system is a phrase coined by the psychological scientist Mark Schaller to refer to a suite of psychological mechanisms that allow individual organisms to detect the potential presence of disease-causing parasites in their immediate environment, and to engage in behaviors that prevent contact with those objects and individuals.

These mechanisms include sensory processes through which cues connoting the presence of parasitic infections are perceived (e.g., the smell of a foul odor, the sight of pox or pustules), as well as stimulus–response systems through which these sensory cues trigger a cascade of aversive affective, cognitive, and behavioral reactions (e.g., arousal of disgust, automatic activation of cognitions that connote the threat of disease, behavioral avoidance).

The existence of a behavioral immune system has been documented across many animal species, including humans. It is theorized that the mechanisms that comprise the behavioral immune system evolved as a crude first line of defense against disease-causing pathogens.

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πŸ”— Joy (Programming Language)

πŸ”— Software πŸ”— Software/Computing

The Joy programming language in computer science is a purely functional programming language that was produced by Manfred von Thun of La Trobe University in Melbourne, Australia. Joy is based on composition of functions rather than lambda calculus. It has turned out to have many similarities to Forth, due not to design but to a sort of parallel evolution and convergence. It was also inspired by the function-level programming style of John Backus's FP.

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πŸ”— OFFSystem

πŸ”— Computing

The Owner-Free File System (OFF System, or OFF for short) is a peer-to-peer distributed file system in which all shared files are represented by randomized multi-used data blocks. Instead of anonymizing the network, the data blocks are anonymized and therefore, only data garbage is ever exchanged and stored and no forwarding via intermediate nodes is required. OFF claims to have been created with the expressed intention "to cut off some gangrene-infested bits of the copyright industry."

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πŸ”— Volkswagen Currywurst

πŸ”— Germany πŸ”— Food and drink πŸ”— Brands

Volkswagen currywurst is a brand of sausage manufactured by the Volkswagen car maker since 1973. It is manufactured at the company's Wolfsburg plant and sold in restaurants in its six German factories. The currywurst are also sold externally at supermarkets and football stadiums and given away to Volkswagen customers. The sausage is branded as a "Volkswagen Original Part" and has been given the part number 199 398 500 A. The product has been described as the most produced of any of Volkswagen's parts, some 6.81 million sausages being manufactured in 2018. In many recent years the company has produced more sausages than cars. A Volkswagen ketchup is also produced and sold to accompany the currywurst.

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πŸ”— Operation Popeye

πŸ”— Military history πŸ”— Military history/North American military history πŸ”— Military history/United States military history πŸ”— Military history/Asian military history πŸ”— Military history/Southeast Asian military history πŸ”— Vietnam

Operation Popeye (Project Controlled Weather Popeye / Motorpool / Intermediary-Compatriot) was a highly classified weather modification program in Southeast Asia during 1967–1972. The cloud seeding operation during the Vietnam War ran from March 20, 1967 until July 5, 1972 in an attempt to extend the monsoon season, specifically over areas of the Ho Chi Minh Trail. The operation was used to induce rain and extend the East Asian Monsoon season in support of U.S. government efforts related to the War in Southeast Asia.

The former U.S. Secretary of Defense, Robert S. McNamara, was aware that there might be objections raised by the international scientific community but said in a memo to the president that such objections had not in the past been a basis for prevention of military activities considered to be in the interests of U.S. national security.

The chemical weather modification program was conducted from Thailand over Cambodia, Laos, and Vietnam and allegedly sponsored by Secretary of State Henry Kissinger and CIA without the authorization of then Secretary of Defense Melvin Laird who had categorically denied to Congress that a program for modification of the weather for use as a tactical weapon even existed.

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πŸ”— 0.999...= 1

πŸ”— Mathematics

In mathematics, 0.999... (also written as 0.9, among other ways) denotes the repeating decimal consisting of infinitely many 9s after the decimal point (and one 0 before it). This repeating decimal represents the smallest number no less than every decimal number in the sequence (0.9, 0.99, 0.999, ...). This number is equal to 1. In other words, "0.999..." and "1" represent the same number. There are many ways of showing this equality, from intuitive arguments to mathematically rigorous proofs. The technique used depends on the target audience, background assumptions, historical context, and preferred development of the real numbers, the system within which 0.999... is commonly defined. (In other systems, 0.999... can have the same meaning, a different definition, or be undefined.)

More generally, every nonzero terminating decimal has two equal representations (for example, 8.32 and 8.31999...), which is a property of all base representations. The utilitarian preference for the terminating decimal representation contributes to the misconception that it is the only representation. For this and other reasonsβ€”such as rigorous proofs relying on non-elementary techniques, properties, or disciplinesβ€”some people can find the equality sufficiently counterintuitive that they question or reject it. This has been the subject of several studies in mathematics education.

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πŸ”— Foucault pendulum

πŸ”— Physics

The Foucault pendulum or Foucault's pendulum is a simple device named after French physicist LΓ©on Foucault and conceived as an experiment to demonstrate the Earth's rotation. The pendulum was introduced in 1851 and was the first experiment to give simple, direct evidence of the earth's rotation. Foucault pendulums today are popular displays in science museums and universities.

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