Random Articles

Have a deep view into what people are curious about.

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.

Discussed on

πŸ”— Vibe Coding

πŸ”— Technology πŸ”— Computing πŸ”— Robotics πŸ”— Artificial Intelligence

Vibe coding, sometimes spelled as vibecoding, is an AI-powered programming practice where you surrender to the "vibes" and power of the AI, while ignoring the details of the generated code. After describing a problem in a few sentences, you watch as the AI codes a custom solution such as an app or website. Vibe coding may feel like sorcery. Amateur programmers can now produce software, with limited features and sometimes imperfectly, that previously would have needed a software team. The practice defies the belief in the software industry that software engineering demands great skill.

Discussed on

πŸ”— Tide-Predicting Machine No. 2

Tide-Predicting Machine No. 2, also known as Old Brass Brains, was a special-purpose mechanical computer that uses gears, pulleys, chains, and other mechanical components to compute the height and time of high and low tides for specific locations. The machine can perform tide calculations much faster than a person could do with pencil and paper. The U.S. Coast and Geodetic Survey put the machine into operation in 1910. It was used until 1965, when it was replaced by an electronic computer.

Discussed on

πŸ”— Comfort Noise

πŸ”— Telecommunications πŸ”— Radio

Comfort noise (or comfort tone) is synthetic background noise used in radio and wireless communications to fill the artificial silence in a transmission resulting from voice activity detection or from the audio clarity of modern digital lines.

Some modern telephone systems (such as wireless and VoIP) use voice activity detection (VAD), a form of squelching where low volume levels are ignored by the transmitting device. In digital audio transmissions, this saves bandwidth of the communications channel by transmitting nothing when the source volume is under a certain threshold, leaving only louder sounds (such as the speaker's voice) to be sent. However, improvements in background noise reduction technologies can occasionally result in the complete removal of all noise. Although maximizing call quality is of primary importance, exhaustive removal of noise may not properly simulate the typical behavior of terminals on the PSTN system.

The result of receiving total silence, especially for a prolonged period, has a number of unwanted effects on the listener, including the following:

  • the listener may believe that the transmission has been lost, and therefore hang up prematurely.
  • the speech may sound "choppy" (see noise gate) and difficult to understand.
  • the sudden change in sound level can be jarring to the listener.

To counteract these effects, comfort noise is added, usually on the receiving end in wireless or VoIP systems, to fill in the silent portions of transmissions with artificial noise. The noise generated is at a low but audible volume level, and can vary based on the average volume level of received signals to minimize jarring transitions.

In many VoIP products, users may control how VAD and comfort noise are configured, or disable the feature entirely.

As part of the RTP audio video profile, RFC 3389 defines a standard for distributing comfort noise information in VoIP systems.

A similar concept is that of sidetone, the effect of sound that is picked up by a telephone's mouthpiece and introduced (at low level) into the earpiece of the same handset, acting as feedback.

During the siege of Leningrad, the beat of a metronome was used as comfort noise on the Leningrad radio network, indicating that the network was still functioning.

Many radio stations broadcast birdsong, city-traffic or other atmospheric comfort noise during periods of deliberate silence. For example, in the UK, silence is observed on Remembrance Sunday, and London's quiet city ambiance is used. This is to reassure the listener that the station is on-air, but primarily to prevent silence detection systems at transmitters from automatically starting backup tapes of music (designed to be broadcast in the case of transmission link failure).

Discussed on

πŸ”— Considered for deletion – Mass killings under communist regimes

πŸ”— Human rights πŸ”— Soviet Union πŸ”— History πŸ”— Death πŸ”— Politics πŸ”— Socialism πŸ”— Soviet Union/history of Russia πŸ”— Soviet Union/Russia

Mass killings under communist regimes occurred throughout the 20th century. Death estimates vary widely, depending on the definitions of the deaths that are included in them. The higher estimates of mass killings account for the crimes that governments committed against civilians, including executions, the destruction of populations through man-made hunger and deaths that occurred during forced deportations and imprisonment, and deaths that resulted from forced labor.

In addition to "mass killings," terms that are used to define such killings include "democide", "politicide", "classicide", and "genocide."

Discussed on

πŸ”— Tensegrity

πŸ”— Technology


Tensegrity, tensional integrity or floating compression is a structural principle based on a system of isolated components under compression inside a network of continuous tension, and arranged in such a way that the compressed members (usually bars or struts) do not touch each other while the prestressed tensioned members (usually cables or tendons) delineate the system spatially.

The term was coined by Buckminster Fuller in the 1960s as a portmanteau of "tensional integrity". The other denomination of tensegrity, floating compression, was used mainly by the constructivist artist Kenneth Snelson.

Discussed on

πŸ”— The Nine Worthies

πŸ”— History πŸ”— Middle Ages πŸ”— Middle Ages/History

The Nine Worthies are nine historical, scriptural, and legendary personages who personify the ideals of chivalry established in the Middle Ages, whose lives were deemed a valuable study for aspirants to chivalric status. All were commonly referred to as 'Princes', regardless of their historical titles. In French they are called Les Neuf Preux or "Nine Valiants", giving a more specific idea of the moral virtues they exemplified: those of soldierly courage and generalship. In Italy they are i Nove Prodi.

The Nine Worthies include three pagans (Hector, Alexander the Great and Julius Caesar), three Jews (Joshua, David and Judas Maccabeus) and three Christians (King Arthur, Charlemagne and Godfrey of Bouillon).

Discussed on

πŸ”— The Baghdad Battery

πŸ”— Iran πŸ”— Alternative Views πŸ”— Iraq

The Baghdad Battery or Parthian Battery is a set of three artifacts which were found together: a ceramic pot, a tube of copper, and a rod of iron. It was discovered in modern Khujut Rabu, Iraq, close to the metropolis of Ctesiphon, the capital of the Parthian (150 BC – 223 AD) and Sasanian (224–650 AD) empires of Persia, and it is considered to date from either of these periods.

Its origin and purpose remain unclear. It was hypothesized by some researchers that the object functioned as a galvanic cell, possibly used for electroplating, or some kind of electrotherapy, but there is no electroplated object known from this period. An alternative explanation is that it functioned as a storage vessel for sacred scrolls.

Discussed on

πŸ”— Angus Barbieri's fast

πŸ”— Biography πŸ”— Medicine πŸ”— Food and drink πŸ”— Scotland

Scottish man Angus Barbieri (1939 – 7 September 1990) fasted for 382 days, from June 1965 to July 1966. He lived on tea, coffee, soda water, and vitamins while living at home in Tayport, Scotland, and frequently visiting Maryfield Hospital for medical evaluation. He lost 276 pounds (125Β kg) and set a record for the length of a fast.

Discussed on