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🔗 History 🔗 Visual arts

The Hockney–Falco thesis is a theory of art history, advanced by artist David Hockney and physicist Charles M. Falco. Both claimed that advances in realism and accuracy in the history of Western art since the Renaissance were primarily the result of optical instruments such as the camera obscura, camera lucida, and curved mirrors, rather than solely due to the development of artistic technique and skill. Nineteenth-century artists' use of photography had been well documented. In a 2001 book, Secret Knowledge: Rediscovering the Lost Techniques of the Old Masters, Hockney analyzed the work of the Old Masters and argued that the level of accuracy represented in their work is impossible to create by "eyeballing it". Since then, Hockney and Falco have produced a number of publications on positive evidence of the use of optical aids, and the historical plausibility of such methods. The hypothesis led to a variety of conferences and heated discussions.

🔗 Computing

In computer programming, program slicing is the computation of the set of program statements, the program slice, that may affect the values at some point of interest, referred to as a slicing criterion. Program slicing can be used in debugging to locate source of errors more easily. Other applications of slicing include software maintenance, optimization, program analysis, and information flow control.

Slicing techniques have been seeing a rapid development since the original definition by Mark Weiser. At first, slicing was only static, i.e., applied on the source code with no other information than the source code. Bogdan Korel and Janusz Laski introduced dynamic slicing, which works on a specific execution of the program (for a given execution trace). Other forms of slicing exist, for instance path slicing.

🔗 Mathematics

The Karnaugh map (KM or K-map) is a method of simplifying Boolean algebra expressions. Maurice Karnaugh introduced it in 1953 as a refinement of Edward Veitch's 1952 Veitch chart, which actually was a rediscovery of Allan Marquand's 1881 logical diagram aka Marquand diagram but with a focus now set on its utility for switching circuits. Veitch charts are therefore also known as Marquand–Veitch diagrams, and Karnaugh maps as Karnaugh–Veitch maps (KV maps).

The Karnaugh map reduces the need for extensive calculations by taking advantage of humans' pattern-recognition capability. It also permits the rapid identification and elimination of potential race conditions.

The required Boolean results are transferred from a truth table onto a two-dimensional grid where, in Karnaugh maps, the cells are ordered in Gray code, and each cell position represents one combination of input conditions, while each cell value represents the corresponding output value. Optimal groups of 1s or 0s are identified, which represent the terms of a canonical form of the logic in the original truth table. These terms can be used to write a minimal Boolean expression representing the required logic.

Karnaugh maps are used to simplify real-world logic requirements so that they can be implemented using a minimum number of physical logic gates. A sum-of-products expression can always be implemented using AND gates feeding into an OR gate, and a product-of-sums expression leads to OR gates feeding an AND gate. Karnaugh maps can also be used to simplify logic expressions in software design. Boolean conditions, as used for example in conditional statements, can get very complicated, which makes the code difficult to read and to maintain. Once minimised, canonical sum-of-products and product-of-sums expressions can be implemented directly using AND and OR logic operators. Diagrammatic and mechanical methods for minimizing simple logic expressions have existed since at least the medieval times. More systematic methods for minimizing complex expressions began to be developed in the early 1950s, but until the mid to late 1980s the Karnaugh map was the most common used in practice.

🔗 Mathematics 🔗 Physics

A topological quantum computer is a theoretical quantum computer that employs two-dimensional quasiparticles called anyons, whose world lines pass around one another to form braids in a three-dimensional spacetime (i.e., one temporal plus two spatial dimensions). These braids form the logic gates that make up the computer. The advantage of a quantum computer based on quantum braids over using trapped quantum particles is that the former is much more stable. Small, cumulative perturbations can cause quantum states to decohere and introduce errors in the computation, but such small perturbations do not change the braids' topological properties. This is like the effort required to cut a string and reattach the ends to form a different braid, as opposed to a ball (representing an ordinary quantum particle in four-dimensional spacetime) bumping into a wall. Alexei Kitaev proposed topological quantum computation in 1997. While the elements of a topological quantum computer originate in a purely mathematical realm, experiments in fractional quantum Hall systems indicate these elements may be created in the real world using semiconductors made of gallium arsenide at a temperature of near absolute zero and subjected to strong magnetic fields.

🔗 Military history 🔗 China 🔗 Urban studies and planning 🔗 Military history/Fortifications 🔗 Military history/Asian military history 🔗 Hong Kong 🔗 Military history/Chinese military history 🔗 Organized crime

Kowloon Walled City was an ungoverned, densely populated settlement in Kowloon City, Hong Kong. Originally a Chinese military fort, the Walled City became an enclave after the New Territories were leased to the UK by China in 1898. Its population increased dramatically following the Japanese occupation of Hong Kong during World War II. By 1990, the walled city contained 50,000 residents within its 2.6-hectare (6.4-acre) borders. From the 1950s to the 1970s, it was controlled by local triads and had high rates of prostitution, gambling, and drug abuse.

In January 1987, the Hong Kong municipal government announced plans to demolish the walled city. After an arduous eviction process, demolition began in March 1993 and was completed in April 1994. Kowloon Walled City Park opened in December 1995 and occupies the area of the former Walled City. Some historical artefacts from the walled city, including its yamen building and remnants of its southern gate, have been preserved there.

🔗 Film 🔗 Marketing & Advertising 🔗 Film/Filmmaking 🔗 Media 🔗 Toys 🔗 Games

Toyetic is a term referring to the suitability of a media property, such as a cartoon or movie, for merchandising tie-in lines of licensed toys, games and novelties. The term is attributed to Bernard Loomis, a toy development executive for Kenner Toys, in discussing the opportunities for marketing the film Close Encounters of the Third Kind, telling its producer Steven Spielberg that the movie wasn't "toyetic" enough, leading Loomis towards acquiring the lucrative license for the upcoming Star Wars properties.

🔗 Computing

This is a record of historically important programming languages, by decade.

🔗 United States 🔗 Film 🔗 Library of Congress 🔗 Film/American cinema 🔗 Film/Silent films 🔗 Film/Documentary films 🔗 United States/Film - American cinema

A Trip Down Market Street is a 13-minute actuality film recorded by placing a movie camera on the front of a cable car as it traveled down San Francisco’s Market Street. The film shows many details of daily life in a major early 20th century American city, including the transportation, fashions and architecture of the era. The film begins at 8th Street and continues eastward to the cable car turntable, at The Embarcadero, in front of the Ferry Building. Landmarks passed in the latter part of the first half include the Call Building (then San Francisco's tallest) and the Palace Hotel (both on the right; Lotta's Fountain is on the left between the two but is in the shade). The film was produced by the four Miles brothers: Harry, Herbert, Earle and Joe. It is notable for capturing San Francisco four days before the 1906 San Francisco earthquake, which started on the morning of Wednesday, April 18, 1906.

The Miles brothers had been producing films in New York including films shot in San Francisco. In September 1905 they shot the fight between Oscar "Battling" Nelson and Jimmy Britt in Colma, California, just south of San Francisco city limits. The Miles brothers established a studio at 1139 Market Street in San Francisco in early 1906. They shot a railroad descent down Mount Tamalpais as well as the Market Street film. On April 17, Harry and Joe Miles boarded a train for New York, taking the two films with them, but they heard about the earthquake and sent the films to New York while they boarded another train headed back to San Francisco. The Turk Street house of Earle Miles survived the earthquake and subsequent catastrophic fire but the studio did not. The Miles brothers based their business out of Earle's home, and shot more film of post-earthquake scenes; some of this footage, including that of a second trip down a now devastated Market Street, reemerged in 2016. It is likely that the Market Street film survives today because it was sent away before the fire.

Several 35mm prints exist with slight changes in footage. Copies are held at the Library of Congress and the Prelinger Archives. A digital version is viewable online at Internet Archive, YouTube and Wikimedia Commons. In 2010, the film was selected for preservation in the National Film Registry by the Library of Congress.

🔗 Cryptography 🔗 Cryptography/Computer science

In cryptography, power analysis is a form of side channel attack in which the attacker studies the power consumption of a cryptographic hardware device (such as a smart card, tamper-resistant "black box", or integrated circuit). The attack can non-invasively extract cryptographic keys and other secret information from the device.

Simple power analysis (SPA) involves visually interpreting power traces, or graphs of electrical activity over time. Differential power analysis (DPA) is a more advanced form of power analysis, which can allow an attacker to compute the intermediate values within cryptographic computations through statistical analysis of data collected from multiple cryptographic operations. SPA and DPA were introduced to the open cryptology community in 1998 by Paul Kocher, Joshua Jaffe and Benjamin Jun.

🔗 Music theory

The Parsons code, formally named the Parsons code for melodic contours, is a simple notation used to identify a piece of music through melodic motion — movements of the pitch up and down. Denys Parsons developed this system for his 1975 book The Directory of Tunes and Musical Themes. Representing a melody in this manner makes it easier to index or search for pieces, particularly when the notes values are unknown.

The book was also published in Germany in 2002 and reprinted by Piatkus as The Directory of Classical Themes in 2008.