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🔗 Internet 🔗 Computing 🔗 Computing/Computer Security 🔗 Computing/Websites 🔗 Computing/Networking

Domain fronting is a technique for Internet censorship circumvention that uses different domain names in different communication layers of an HTTPS connection to discreetly connect to a different target domain than is discernable to third parties monitoring the requests and connections.

Due to quirks in security certificates, the redirect systems of the content delivery networks (CDNs) used as 'domain fronts', and the protection provided by HTTPS, censors are typically unable to differentiate circumvention ("domain-fronted") traffic from overt non-fronted traffic for any given domain name. As such they are forced to either allow all traffic to the domain front—including circumvention traffic—or block the domain front entirely, which may result in expensive collateral damage and has been likened to "blocking the rest of the Internet".

Domain fronting does not conform to HTTP standards that require the SNI extension and HTTP Host header to contain the same domain. Many large cloud service providers, including Amazon, Microsoft, and Google, actively prohibit domain fronting, which has limited it as a censorship bypass technique. Pressure from censors in Russia and China is thought to have contributed to these prohibitions, but domain fronting can also be used maliciously.

A newer variant of domain fronting, domain hiding, passes an encrypted request for one resource (say, a website), concealed behind an unencrypted (plaintext) request for another resource whose DNS records are stored in the same cloud. It has much the same effect. Refraction networking is an application of the broader principle.

🔗 Biography 🔗 China/Chinese history 🔗 Italy 🔗 China

Katarina Vilioni (died 1342) was one of the first Europeans known to have resided in China. She was apparently a member of a Genoese trading family that lived in Yangzhou during the mid-14th century.

Vilioni is known through her tombstone, which was rediscovered at Yangzhou in 1951. It suggests that Vilioni died in 1342 and was the daughter of a man named Domenico Vilioni.

🔗 Electronics

The 7400 series of integrated circuits (ICs) are a popular logic family of transistor–transistor logic (TTL) logic chips.

In 1964, Texas Instruments introduced the SN5400 series of logic chips, in a ceramic semiconductor package. A low-cost plastic package SN7400 series was introduced in 1966 which quickly gained over 50% of the logic chip market, and eventually becoming de facto standardized electronic components. Over the decades, many generations of pin-compatible descendant families evolved to include support for low power CMOS technology, lower supply voltages, and surface mount packages.

🔗 Physics 🔗 Astronomy

Rømer's determination of the speed of light was the demonstration in 1676 that light has a finite speed and so does not travel instantaneously. The discovery is usually attributed to Danish astronomer Ole Rømer, who was working at the Royal Observatory in Paris at the time.

By timing the eclipses of the Jovian moon Io, Rømer estimated that light would take about 22 minutes to travel a distance equal to the diameter of Earth's orbit around the Sun. This would give light a velocity of about 220,000 kilometres per second, about 26% lower than the true value of 299,792 km/s.

Rømer's theory was controversial at the time that he announced it and he never convinced the director of the Paris Observatory, Giovanni Domenico Cassini, to fully accept it. However, it quickly gained support among other natural philosophers of the period such as Christiaan Huygens and Isaac Newton. It was finally confirmed nearly two decades after Rømer's death, with the explanation in 1729 of stellar aberration by the English astronomer James Bradley.

🔗 Germany 🔗 Disaster management 🔗 European history 🔗 Royalty and Nobility 🔗 Germany/Holy Roman Empire

In July 1184, Henry VI, King of Germany (later Holy Roman Emperor), held court at a Hoftag in the Petersberg Citadel in Erfurt. On the morning of 26 July, the combined weight of the assembled nobles caused the wooden second story floor of the building to collapse and most of them fell through into the latrine cesspit below the ground floor, where about 60 of them drowned in liquid excrement. This event is called Erfurter Latrinensturz (lit. 'Erfurt latrine fall') in several German sources.

🔗 Transport 🔗 Cycling

The Idaho stop is the common name for laws that allow cyclists to treat a stop sign as a yield sign, and a red light as a stop sign. It first became law in Idaho in 1982, but was not adopted elsewhere until Delaware adopted a limited stop-as-yield law, the "Delaware Yield", in 2017. Arkansas was the second state to legalize both stop-as-yield and red light-as-stop in April 2019. Studies in Delaware and Idaho have shown significant decreases in crashes at stop-controlled intersections.

🔗 Computing 🔗 Military history 🔗 Military history/Military science, technology, and theory 🔗 Cryptography 🔗 Cryptography/Computer science 🔗 Poland 🔗 Computing/Early computers

The bomba, or bomba kryptologiczna (Polish for "bomb" or "cryptologic bomb"), was a special-purpose machine designed around October 1938 by Polish Cipher Bureau cryptologist Marian Rejewski to break German Enigma-machine ciphers.

🔗 Physiology 🔗 Molecular Biology 🔗 Physiology/cell 🔗 Molecular Biology/Molecular and Cell Biology

Peto's paradox is an observation that at the species level, the incidence of cancer does not appear to correlate with the number of cells in an organism. For example, the incidence of cancer in humans is much higher than the incidence of cancer in whales, despite whales having more cells than humans. If the probability of carcinogenesis were constant across cells, one would expect whales to have a higher incidence of cancer than humans. Peto's paradox is named after English statistician and epidemiologist Richard Peto, who first observed the connection.

🔗 Mathematics

In number theory, specifically the study of Diophantine approximation, the lonely runner conjecture is a conjecture about the long-term behavior of runners on a circular track. It states that ${\displaystyle n}$ runners on a track of unit length, with constant speeds all distinct from one another, will each be lonely at some time—at least ${\displaystyle 1/n}$ units away from all others.

The conjecture was first posed in 1967 by German mathematician Jörg M. Wills, in purely number-theoretic terms, and independently in 1974 by T. W. Cusick; its illustrative and now-popular formulation dates to 1998. The conjecture is known to be true for 7 runners or less, but the general case remains unsolved. Implications of the conjecture include solutions to view-obstruction problems and bounds on properties, related to chromatic numbers, of certain graphs.

🔗 Mathematics 🔗 Statistics

Anscombe's quartet comprises four data sets that have nearly identical simple descriptive statistics, yet have very different distributions and appear very different when graphed. Each dataset consists of eleven (x,y) points. They were constructed in 1973 by the statistician Francis Anscombe to demonstrate both the importance of graphing data when analyzing it, and the effect of outliers and other influential observations on statistical properties. He described the article as being intended to counter the impression among statisticians that "numerical calculations are exact, but graphs are rough."