Random Articles (Page 4)

Have a deep view into what people are curious about.

🔗 Soar (Cognitive Architecture)

🔗 Cognitive science

Soar is a cognitive architecture, originally created by John Laird, Allen Newell, and Paul Rosenbloom at Carnegie Mellon University. (Rosenbloom continued to serve as co-principal investigator after moving to Stanford University, then to the University of Southern California's Information Sciences Institute.) It is now maintained and developed by John Laird's research group at the University of Michigan.

The goal of the Soar project is to develop the fixed computational building blocks necessary for general intelligent agents – agents that can perform a wide range of tasks and encode, use, and learn all types of knowledge to realize the full range of cognitive capabilities found in humans, such as decision making, problem solving, planning, and natural language understanding. It is both a theory of what cognition is and a computational implementation of that theory. Since its beginnings in 1983 as John Laird’s thesis, it has been widely used by AI researchers to create intelligent agents and cognitive models of different aspects of human behavior. The most current and comprehensive description of Soar is the 2012 book, The Soar Cognitive Architecture.

Discussed on

🔗 Blinking Twelve Problem

🔗 Computing

The blinking twelve problem is a term used in software design. It usually refers to features in software or computer systems which are rendered unusable to most users by the complexity of the interface to them.

The usage emanates from the 'clock' feature provided on many VCRs manufactured in the late 1980s or early 1990s. The clock could be set by using a combination of buttons provided on the VCR in a specific sequence that was found complicated by most users. As a result, VCR users were known to seldom set the time on the VCR clock. This resulted in the default time of '12:00' blinking on the VCR display at all times of the day, which is the origin of this term.

"In most surveys, the majority of people have never time-shifted just because they don't know how to program their machines," said Tom Adams, a television analyst for Paul Kagan Associates, a media research firm, in 1990.

In software, 'the blinking twelve problem' thus refers to any situation in which features or functions of a program go unused for reasons that the designers never anticipated, largely because developers were unable to anticipate the level of understanding the users would have of the technology. The term may also refer to the challenge faced by developers of addressing the real causes of users' difficulties, as well as the challenge of providing helpful documentation or technical support without knowing beforehand how well the user understands their own problem.

In other instances, it can be used to reference the lack of basic user-friendly features in complex systems; stemming from the lack of a backup battery to keep the clock setting in a $300 VCR during even the briefest power interruption, when a $10 clock would have one.

The terms is usually used mostly by geeks, often in discussion forums. The term appears in the 1999 essay In the Beginning... Was the Command Line by Neal Stephenson.

Discussed on

🔗 FRACTRAN

🔗 Computing

FRACTRAN is a Turing-complete esoteric programming language invented by the mathematician John Conway. A FRACTRAN program is an ordered list of positive fractions together with an initial positive integer input n. The program is run by updating the integer n as follows:

  1. for the first fraction f in the list for which nf is an integer, replace n by nf
  2. repeat this rule until no fraction in the list produces an integer when multiplied by n, then halt.

Conway 1987 gives the following formula for primes in FRACTRAN:

( 17 91 , 78 85 , 19 51 , 23 38 , 29 33 , 77 29 , 95 23 , 77 19 , 1 17 , 11 13 , 13 11 , 15 2 , 1 7 , 55 1 ) {\displaystyle \left({\frac {17}{91}},{\frac {78}{85}},{\frac {19}{51}},{\frac {23}{38}},{\frac {29}{33}},{\frac {77}{29}},{\frac {95}{23}},{\frac {77}{19}},{\frac {1}{17}},{\frac {11}{13}},{\frac {13}{11}},{\frac {15}{2}},{\frac {1}{7}},{\frac {55}{1}}\right)}

Starting with n=2, this FRACTRAN program generates the following sequence of integers:

2, 15, 825, 725, 1925, 2275, 425, 390, 330, 290, 770, ... (sequence A007542 in the OEIS)

After 2, this sequence contains the following powers of 2:

2 2 = 4 , 2 3 = 8 , 2 5 = 32 , 2 7 = 128 , 2 11 = 2048 , 2 13 = 8192 , 2 17 = 131072 , 2 19 = 524288 , {\displaystyle 2^{2}=4,\,2^{3}=8,\,2^{5}=32,\,2^{7}=128,\,2^{11}=2048,\,2^{13}=8192,\,2^{17}=131072,\,2^{19}=524288,\,\dots } (sequence A034785 in the OEIS)

which are the prime powers of 2.

Discussed on

🔗 Democratic Backsliding

🔗 Human rights 🔗 Law 🔗 Politics 🔗 Elections and Referendums

Democratic backsliding is a form of autocratization, a process of regime change toward authoritarianism in which the exercise of political power becomes less limited and more arbitrary and repressive. Democratic backsliding specifically assumes a starting point of a democratic system. The process typically restricts the space for public contest and political participation in the process of government selection. Democratic backsliding involves the weakening of democratic institutions, such as the peaceful transition of power or free and fair elections, or the violation of individual rights that underpin democracies, especially freedom of expression. Democratic backsliding is the opposite of democratization.

Democratic backsliding is a gradual process, composed of instances of decline. It is not sudden nor dramatic, and typically follows legal processes to weaken democratic institutions. The Democratic Erosion Consortium categorizes these events of erosion into precursors, symptoms, acts of resistance to backsliding, and destabilizing events.

Proposed causes of democratic backsliding include economic inequality, unemployment, culture wars, culturally conservative reactions to societal changes, populist or personalist politics, and external influence from great power politics. Economic inequality is strongly associated with democratic backsliding in the 21st century, even in wealthy democracies. During crises, backsliding can occur when leaders impose autocratic rules during states of emergency that are either disproportionate to the severity of the crisis or remain in place after the situation has improved.

During the Cold War, democratic backsliding occurred most frequently through coups. Since the end of the Cold War, democratic backsliding has occurred more frequently through the election of personalist leaders or parties who subsequently dismantle democratic institutions. During the third wave of democratization in the late twentieth century, many new, weakly institutionalized democracies were established; these regimes have been most vulnerable to democratic backsliding. The third wave of autocratization has been ongoing since 2010 after the Great Recession, when the number of liberal democracies was at an all-time high. More than half of all autocratization episodes over 1900–2023 have a U-turn shape in which the autocratization is closely followed by and linked to subsequent democratization.

🔗 Penn Effect

🔗 Economics

The Penn effect is the economic finding that real income ratios between high and low income countries are systematically exaggerated by gross domestic product (GDP) conversion at market exchange rates. It is associated with what became the Penn World Table, and it has been a consistent econometric result since at least the 1950s.

The "Balassa–Samuelson effect" is a model cited as the principal cause of the Penn effect by neo-classical economics, as well as being a synonym of "Penn effect".

Discussed on

🔗 Vigenère Cipher

🔗 Italy 🔗 Cryptography 🔗 Cryptography/Computer science

The Vigenère cipher (French pronunciation: ​[viʒnɛːʁ]) is a method of encrypting alphabetic text by using a series of interwoven Caesar ciphers, based on the letters of a keyword. It employs a form of polyalphabetic substitution.

First described by Giovan Battista Bellaso in 1553, the cipher is easy to understand and implement, but it resisted all attempts to break it until 1863, three centuries later. This earned it the description le chiffre indéchiffrable (French for 'the indecipherable cipher'). Many people have tried to implement encryption schemes that are essentially Vigenère ciphers. In 1863, Friedrich Kasiski was the first to publish a general method of deciphering Vigenère ciphers.

In the 19th century the scheme was misattributed to Blaise de Vigenère (1523–1596), and so acquired its present name.

Discussed on

🔗 Space Infrastructure Servicing

🔗 Spaceflight

Space Infrastructure Servicing (SIS) is a spacecraft being developed by Canadian aerospace firm MacDonald, Dettwiler and Associates to operate as a small-scale in-space refueling depot for communication satellites in geosynchronous orbit.

In June 2017, SSL announced its first commercial customer, Luxembourg-based satellite owner/operator SES S.A.

Discussed on

🔗 Magnetic Shark Repellent

🔗 Sharks

Magnetic shark repellents utilize permanent magnets, which exploit the sensitivity of the Ampullae of Lorenzini in sharks and rays (electrosense). This organ is not found on bony fish (teleosts), therefore, this type of shark repellent is selective to sharks and rays. Permanent magnets do not require power input, making them ideal for use in fisheries and as bycatch reduction devices. Sharkbanz, released in 2014, is a wearable commercially available device intended for recreational users.

Discussed on

🔗 World Game

🔗 Politics

World Game, sometimes called the World Peace Game, is an educational simulation developed by Buckminster Fuller in 1961 to help create solutions to overpopulation and the uneven distribution of global resources. This alternative to war games uses Fuller's Dymaxion map and requires a group of players to cooperatively solve a set of metaphorical scenarios, thus challenging the dominant nation-state perspective with a more holistic "total world" view. The idea was to "make the world work for 100% of humanity in the shortest possible time through spontaneous cooperation without ecological damage or disadvantage to anyone," thus increasing the quality of life for all people.

🔗 Ultraviolet catastrophe

🔗 Physics 🔗 History of Science

The ultraviolet catastrophe, also called the Rayleigh–Jeans catastrophe, was the prediction of late 19th century to early 20th century classical physics that an ideal black body at thermal equilibrium would emit an unbounded quantity of energy as wavelength decreased into the ultraviolet range.: 6–7  The term "ultraviolet catastrophe" was first used in 1911 by Paul Ehrenfest, but the concept originated with the 1900 statistical derivation of the Rayleigh–Jeans law.

The phrase refers to the fact that the empirically derived Rayleigh–Jeans law, which accurately predicted experimental results at large wavelengths, failed to do so for short wavelengths. (See the image for further elaboration.) As the theory diverged from empirical observations when these frequencies reached the ultraviolet region of the electromagnetic spectrum, there was a problem. This problem was later found to be due to a property of quanta as proposed by Max Planck: There could be no fraction of a discrete energy package already carrying minimal energy.

Since the first use of this term, it has also been used for other predictions of a similar nature, as in quantum electrodynamics and such cases as ultraviolet divergence.

Discussed on