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π Evercookie
Evercookie is a JavaScript-based application created by Samy Kamkar that produces zombie cookies in a web browser that are intentionally difficult to delete. In 2013, a top-secret NSA document was leaked by Edward Snowden, citing Evercookie as a method of tracking Tor users.
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- "Evercookie" | 2011-04-05 | 75 Upvotes 17 Comments
π The SOLID principles of object-oriented design
In object-oriented computer programming, SOLID is a mnemonic acronym for five design principles intended to make software designs more understandable, flexible and maintainable. It is not related to the GRASP software design principles. The principles are a subset of many principles promoted by American software engineer and instructor Robert C. Martin. Though they apply to any object-oriented design, the SOLID principles can also form a core philosophy for methodologies such as agile development or adaptive software development. The theory of SOLID principles was introduced by Martin in his 2000 paper Design Principles and Design Patterns, although the SOLID acronym was introduced later by Michael Feathers.
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- "The SOLID principles of object-oriented design" | 2013-12-15 | 58 Upvotes 19 Comments
π Sussman anomaly
The Sussman anomaly is a problem in artificial intelligence, first described by Gerald Sussman, that illustrates a weakness of noninterleaved planning algorithms, which were prominent in the early 1970s. In the problem, three blocks (labeled A, B, and C) rest on a table. The agent must stack the blocks such that A is atop B, which in turn is atop C. However, it may only move one block at a time. The problem starts with B on the table, C atop A, and A on the table:
However, noninterleaved planners typically separate the goal (stack A atop B atop C) into subgoals, such as:
- get A atop B
- get B atop C
Suppose the planner starts by pursuing Goal 1. The straightforward solution is to move C out of the way, then move A atop B. But while this sequence accomplishes Goal 1, the agent cannot now pursue Goal 2 without undoing Goal 1, since both A and B must be moved atop C:
If instead the planner starts with Goal 2, the most efficient solution is to move B. But again, the planner cannot pursue Goal 1 without undoing Goal 2:
The problem was first identified by Sussman as a part of his PhD research. Sussman (and his supervisor, Marvin Minsky) believed that intelligence requires a list of exceptions or tricks, and developed a modular planning system for "debugging" plans. Most modern planning systems can handle this anomaly, but it is still useful for explaining why planning is non-trivial.
Discussed on
- "Sussman anomaly" | 2018-01-15 | 151 Upvotes 41 Comments
π Overburden Conveyor Bridge F60
F60 is the series designation of five overburden conveyor bridges used in brown coal (lignite) opencast mining in the Lusatian coalfields in Germany. They were built by the former Volkseigener Betrieb TAKRAF in Lauchhammer and are the largest movable technical industrial machines in the world. As overburden conveyor bridges, they transport the overburden which lies over the coal seam. The cutting height is 60Β m (200Β ft), hence the name F60. In total, the F60 is up to 80Β m (260Β ft) high and 240Β m (790Β ft) wide; with a length of 502Β m (1,647Β ft), it is described as the lying Eiffel tower, making these behemoths not only the longest vehicle ever madeβbeating Seawise Giant, the longest shipβbut the largest vehicle by physical dimensions ever made by humankind. In operating condition, it weighs 13,600Β metricΒ tons making the F60 also one of the heaviest land vehicles ever made, beaten only by Bagger 293, which is a giant bucket-wheel excavator. Nevertheless, despite its immense size, it is operated by only a crew of 14.
The first conveyor bridge was built from 1969 to 1972, being equipped with a feeder bridge in 1977. The second was built from 1972 to 1974, having been equipped with a feeder bridge during construction. The third conveyor bridge was built from 1976 to 1978, being provided with a feeder bridge in 1985. The fourth and fifth conveyor bridges were built 1986β1988 and 1988β1991 respectively.
There are still four F60s in operation in the Lusatian coalfields today: in the brown coal opencast mines in JΓ€nschwalde (Brandenburg, near JΓ€nschwalde Power Station), Welzow-SΓΌd (Brandenburg, near Schwarze Pumpe Power Station), Nochten and Reichwalde (Saxony, both near Boxberg Power Station). The fifth F60, the last one built, is in Lichterfeld-Schacksdorf and is accessible to visitors.
Discussed on
- "Overburden Conveyor Bridge F60" | 2024-02-10 | 36 Upvotes 11 Comments
π Holographic Data Storage
Holographic data storage is a potential technology in the area of high-capacity data storage. While magnetic and optical data storage devices rely on individual bits being stored as distinct magnetic or optical changes on the surface of the recording medium, holographic data storage records information throughout the volume of the medium and is capable of recording multiple images in the same area utilizing light at different angles.
Additionally, whereas magnetic and optical data storage records information a bit at a time in a linear fashion, holographic storage is capable of recording and reading millions of bits in parallel, enabling data transfer rates greater than those attained by traditional optical storage.
π Lists of corporate assets
This page is an index for lists of some assets owned by large corporations.
Discussed on
- "Lists of corporate assets" | 2020-04-23 | 22 Upvotes 1 Comments
π Core War
Core War is a 1984 programming game created by D. G. Jones and A. K. Dewdney in which two or more battle programs (called "warriors") compete for control of a virtual computer. These battle programs are written in an abstract assembly language called Redcode.
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- "Core War, a very old game about programming" | 2023-08-14 | 66 Upvotes 14 Comments
- "Core War" | 2022-02-11 | 236 Upvotes 50 Comments
π GNU Guix System
GNU Guix System or Guix System (previously GuixSD) is a rolling release, free and open source Linux distribution built around the GNU Guix package manager. It enables a declarative operating system configuration and allows reliable system upgrades that can easily be rolled back. It uses the GNU Shepherd init system and the Linux-libre kernel, with support for the GNU Hurd kernel under development. On February 3, 2015, the distribution was added to the Free Software Foundation's list of free Linux distributions. The Guix package manager and the Guix System drew inspiration from the Nix package manager and NixOS respectively.
Discussed on
- "GNU Guix System" | 2022-05-27 | 68 Upvotes 56 Comments
π Great Ape Personhood
Great ape personhood is a movement to extend personhood and some legal protections to the non-human members of the Hominidae or great ape family: chimpanzees, bonobos, gorillas, and orangutans.
Advocates include primatologists Jane Goodall and Dawn Prince-Hughes, evolutionary biologist Richard Dawkins, philosophers Paola Cavalieri and Peter Singer, and legal scholar Steven Wise.
Discussed on
- "Great Ape Personhood" | 2019-07-30 | 26 Upvotes 4 Comments
π TV detector van
TV detector vans are vans, which, according to the BBC, contain equipment that can detect the presence of television sets in use. The vans are operated by contractors working for the BBC, to enforce the television licensing system in the UK, the Channel Islands and on the Isle of Man. The veracity of their operation has been called into question in the media.
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- "TV Detector Vans" | 2023-12-14 | 71 Upvotes 81 Comments
- "TV detector van" | 2019-08-08 | 151 Upvotes 327 Comments