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🔗 Cryptography 🔗 Cryptography/Computer science

Bacon's cipher or the Baconian cipher is a method of steganographic message encoding devised by Francis Bacon in 1605. A message is concealed in the presentation of text, rather than its content. Bacon cipher is categorized as both a substitution cipher (in plain code) and a concealment cipher (using the two typefaces).

🔗 United States/U.S. Government 🔗 United States 🔗 Biography 🔗 International relations 🔗 Human rights 🔗 Mass surveillance 🔗 Espionage 🔗 United States/North Carolina

Edward Joseph Snowden (born June 21, 1983) is an American whistleblower who copied and leaked highly classified information from the National Security Agency (NSA) in 2013 when he was a Central Intelligence Agency (CIA) employee and subcontractor. His disclosures revealed numerous global surveillance programs, many run by the NSA and the Five Eyes Intelligence Alliance with the cooperation of telecommunication companies and European governments, and prompted a cultural discussion about national security and individual privacy.

In 2013, Snowden was hired by an NSA contractor, Booz Allen Hamilton, after previous employment with Dell and the CIA. Snowden says he gradually became disillusioned with the programs with which he was involved and that he tried to raise his ethical concerns through internal channels but was ignored. On May 20, 2013, Snowden flew to Hong Kong after leaving his job at an NSA facility in Hawaii, and in early June he revealed thousands of classified NSA documents to journalists Glenn Greenwald, Laura Poitras, and Ewen MacAskill. Snowden came to international attention after stories based on the material appeared in The Guardian and The Washington Post. Further disclosures were made by other publications including Der Spiegel and The New York Times.

On June 21, 2013, the United States Department of Justice unsealed charges against Snowden of two counts of violating the Espionage Act of 1917 and theft of government property, following which the Department of State revoked his passport. Two days later, he flew into Moscow's Sheremetyevo Airport, where Russian authorities noted that his U.S. passport had been cancelled, and he was restricted to the airport terminal for over one month. Russia later granted Snowden the right of asylum with an initial visa for residence for one year, and repeated extensions have permitted him to stay at least until 2020. In early 2016, he became the president of the Freedom of the Press Foundation, a San Francisco-based organization that states its purpose is to protect journalists from hacking and government surveillance.

On September 17, 2019, his memoir Permanent Record was published. On the first day of publication, the U.S. Department of Justice filed a civil lawsuit against Snowden over publication of his memoir, alleging he had breached nondisclosure agreements signed with the U.S. federal government. Former The Guardian national security reporter Ewen MacAskill called the civil lawsuit a "huge mistake", noting that the "UK ban of Spycatcher 30 years ago created huge demand". The memoir was listed as no. 1 on Amazon's bestseller list that same day. In an interview with Amy Goodman on Democracy Now! on September 26, 2019, Snowden clarified he considers himself a "whistleblower" as opposed to a "leaker" as he considers "a leaker only distributes information for personal gain".

🔗 Computing 🔗 Computing/Computer hardware

In the x86 architecture, the CPUID instruction (identified by a CPUID opcode) is a processor supplementary instruction (its name derived from CPU IDentification) allowing software to discover details of the processor. It was introduced by Intel in 1993 with the launch of the Pentium and SL-enhanced 486 processors.

A program can use the CPUID to determine processor type and whether features such as MMX/SSE are implemented.

🔗 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.

🔗 Books

The Hacker's Diet (humorously subtitled "How to lose weight and hair through stress and poor nutrition") is a diet plan created by the founder of Autodesk, John Walker, outlined in an electronic book of the same name, that attempts to aid the process of weight loss by more accurately modeling how calories consumed and calories expended actually impact weight. Walker notes that much of our fat free mass introduces signal noise when trying to determine how much weight we're actually losing or gaining. With the help of a graphing tool (Excel is used in the book), he addresses these problems. Factoring in exercise, and through counting calories, one can calculate one's own total energy expenditure (basal metabolic rate, thermic effect of food, and day-to-day exercise) and cut back calorie intake or increase exercise to lose weight.

🔗 Transport 🔗 Urban studies and planning

A road diet (also called a lane reduction, road rechannelization or road conversion) is a technique in transportation planning whereby the number and/or the width of travel lanes of the road is reduced, often to achieve a reduction in crash rates.

🔗 New Zealand 🔗 Maps

New Zealand has often been omitted from maps of the world, which has caught the attention of New Zealanders. It is considered that this is because of the widespread use of the Mercator projection, a map projection putting Europe in the center which leaves New Zealand in the bottom right-hand corner of maps, sometimes making it go overlooked by mapmakers, easily removed by an accidental crop, or simply not added for convenience, ignorance or laziness.

New Zealand has been excluded from maps at the National Museum of Natural History in Washington, D.C. in the United States, in IKEA stores, on the map of the board games Pandemic and Risk, on the map of the 2014 Nuclear Security Summit in which Prime Minister of New Zealand John Key participated, at a world map seal at the United Nations Office at Geneva in Switzerland, on the newspaper Daily Mail, on Government Executive's newsletter Defense One, on the magazine Forbes, on the digital media platform Mashable, on the Pyongyang International Airport in North Korea and on the logo of the Flat Earth Society. It was also excluded from maps promoting the 2015 Rugby World Cup even though New Zealand was the then world champion.

This recurrent occurrence has become a meme for New Zealanders. There is a community on Tumblr titled World Maps Without New Zealand and a Reddit community known as r/MapsWithoutNZ both focused on this issue with 10,000 and 30,000 members respectively as of 2017. In 2019, a user in r/MapsWithoutNZ noticed that a map, "BJÖRKSTA world map", on sale for 30 dollars at an IKEA store on Washington, D.C., did not portray New Zealand. Subsequently, IKEA apologized and removed the product from its stores. On Reddit, there also are communities about the omission of Flevoland in the Netherlands, Hawaii in the United States and Tasmania in Australia from world maps.

The New Zealand Government has acknowledged this phenomenon, and it features a map of the world in which the country is deliberately not included on the 404 error page of its official website; the page states that "something's missing". Furthermore, in 2018, a tourism campaign video was published in which the Prime Minister of New Zealand Jacinda Ardern and the New Zealander actor and comedian Rhys Darby discussed why New Zealand was being left off world maps. On the video, Darby jokingly said that it was the result of a conspiracy against New Zealand. The video promoted the hashtag #getnzonthemap.

🔗 Food and drink 🔗 United Kingdom

A toast sandwich is a sandwich made with two slices of bread in which the filling is a thin slice of toasted bread, which can be heavily buttered. An 1861 recipe says to add salt and pepper to taste.

🔗 China/Chinese history 🔗 China 🔗 Toys

The bamboo-copter, also known as the bamboo dragonfly or Chinese top (Chinese zhuqingting (竹蜻蜓), Japanese taketonbo 竹蜻蛉), is a toy helicopter rotor that flies up when its shaft is rapidly spun. This helicopter-like top originated in Jin dynasty China around 320 AD, and was the object of early experiments by English engineer George Cayley, the inventor of modern aeronautics.

In China, the earliest known flying toys consisted of feathers at the end of a stick, which was rapidly spun between the hands and released into flight. "While the Chinese top was no more than a toy, it is perhaps the first tangible device of what we may understand as a helicopter."

The Jin dynasty Daoist philosopher Ge Hong's (c. 317) book Baopuzi (抱樸子 "Master Who Embraces Simplicity") mentioned a flying vehicle in what Joseph Needham calls "truly an astonishing passage".

Some have made flying cars [feiche 飛車] with wood from the inner part of the jujube tree, using ox-leather (straps) fastened to returning blades so as to set the machine in motion [huan jian yi yin chiji 環劍以引其機]. Others have had the idea of making five snakes, six dragons and three oxen, to meet the "hard wind" [gangfeng 罡風] and ride on it, not stopping until they have risen to a height of forty li. That region is called [Taiqing 太清] (the purest of empty space). There the [qi] is extremely hard, so much so that it can overcome (the strength of) human beings. As the Teacher says: "The kite (bird) flies higher and higher spirally, and then only needs to stretch its two wings, beating the air no more, in order to go forward by itself. This is because it starts gliding (lit. riding) on the 'hard wind' [gangqi 罡炁]. Take dragons, for example; when they first rise they go up using the clouds as steps, and after they have attained a height of forty li then they rush forward effortlessly (lit. automatically) (gliding)." This account comes from the adepts [xianren 仙人], and is handed down to ordinary people, but they are not likely to understand it.

Needham concludes that Ge Hong was describing helicopter tops because "'returning (or revolving) blades' can hardly mean anything else, especially in close association with a belt or strap"; and suggests that "snakes", "dragons", and "oxen" refer to shapes of man-lifting kites. Other scholars interpret this Baopuzi passage mythologically instead of literally, based on its context's mentioning fantastic flights through chengqiao (乘蹻 "riding on tiptoe/stilts") and xian (仙 "immortal; adept") techniques. For instance, "If you can ride the arches of your feet, you will be able to wander anywhere in the world without hindrance from mountains or rivers … Whoever takes the correct amulet and gives serious thought to the process may travel a thousand miles by concentrating his thoughts for one double hour." Compare this translation.

Some build a flying vehicle from the pith of the jujube tree and have it drawn by a sword with a thong of buffalo hide at the end of its grip. Others let their thoughts dwell on the preparation of a joint rectangle from five serpents, six dragons, and three buffaloes, and mount in this for forty miles to the region known as Paradise.

This Chinese helicopter toy was introduced into Europe and "made its earliest appearances in Renaissance European paintings and in the drawings of Leonardo da Vinci." The toy helicopter appears in a c. 1460 French picture of the Madonna and Child at the Musée du Palais de Tesse’ in Mans depicting the Child holding a toy copter sitting in Mary’s lap next to St Benôit (unknown artist), and in a 16th-century stained glass panel at the Victoria and Albert Museum in London. A picture from c. 1560 by Pieter Breughel the Elder at the Kunsthistorisches Museum in Vienna, Children's Games, depicts a helicopter top with three airscrews.

"The helicopter top in China led to nothing but amusement and pleasure, but fourteen hundred years later it was to be one of the key elements in the birth of modern aeronautics in the West." Early Western scientists developed flying machines based upon the original Chinese model. The Russian polymath Mikhail Lomonosov developed a spring-driven coaxial rotor in 1743, and the French naturalist Christian de Launoy created a bow drill device with contra-rotating feather propellers.

In 1792, George Cayley began experimenting with helicopter tops, which he later called "rotary wafts" or "elevating fliers". His landmark (1809) article "On Aerial Navigation" pictured and described a flying model with two propellers (constructed from corks and feathers) powered by a whalebone bow drill. "In 1835 Cayley remarked that while the original toy would rise no more than about 20 or 25 feet (6 or 7.5 metres), his improved models would 'mount upward of 90 ft (27 metres) into the air'. This then was the direct ancestor of the helicopter rotor and the aircraft propeller."

Discussing the history of Chinese inventiveness, the British scientist, sinologist, and historian Joseph Needham wrote, "Some inventions seem to have arisen merely from a whimsical curiosity, such as the 'hot air balloons' made from eggshells which did not lead to any aeronautical use or aerodynamic discoveries, or the zoetrope which did not lead onto the kinematograph, or the helicopter top which did not lead to the helicopter."

🔗 Physics 🔗 Physics/relativity

In theoretical physics, particularly in discussions of gravitation theories, Mach's principle (or Mach's conjecture) is the name given by Einstein to an imprecise hypothesis often credited to the physicist and philosopher Ernst Mach. The hypothesis attempted to explain how rotating objects, such as gyroscopes and spinning celestial bodies, maintain a frame of reference.

The proposition is that the existence of absolute rotation (the distinction of local inertial frames vs. rotating reference frames) is determined by the large-scale distribution of matter, as exemplified by this anecdote:

You are standing in a field looking at the stars. Your arms are resting freely at your side, and you see that the distant stars are not moving. Now start spinning. The stars are whirling around you and your arms are pulled away from your body. Why should your arms be pulled away when the stars are whirling? Why should they be dangling freely when the stars don't move?

Mach's principle says that this is not a coincidence—that there is a physical law that relates the motion of the distant stars to the local inertial frame. If you see all the stars whirling around you, Mach suggests that there is some physical law which would make it so you would feel a centrifugal force. There are a number of rival formulations of the principle, often stated in vague ways like "mass out there influences inertia here". A very general statement of Mach's principle is "local physical laws are determined by the large-scale structure of the universe".

Mach's concept was a guiding factor in Einstein's development of the general theory of relativity. Einstein realized that the overall distribution of matter would determine the metric tensor which indicates which frame is stationary with respect to rotation. Frame-dragging and conservation of gravitational angular momentum makes this into a true statement in the general theory in certain solutions. But because the principle is so vague, many distinct statements have been made which would qualify as a Mach principle, and some of which are false. The Gödel rotating universe is a solution of the field equations that is designed to disobey Mach's principle in the worst possible way. In this example, the distant stars seem to be revolving faster and faster as one moves further away. This example does not completely settle the question of the physical relevance of the principle because it has closed timelike curves.