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🔗 Computing 🔗 Computer science 🔗 Computing/Software 🔗 Computing/Computer science

In computer science, the Rabin–Karp algorithm or Karp–Rabin algorithm is a string-searching algorithm created by Richard M. Karp and Michael O. Rabin (1987) that uses hashing to find an exact match of a pattern string in a text. It uses a rolling hash to quickly filter out positions of the text that cannot match the pattern, and then checks for a match at the remaining positions. Generalizations of the same idea can be used to find more than one match of a single pattern, or to find matches for more than one pattern.

To find a single match of a single pattern, the expected time of the algorithm is linear in the combined length of the pattern and text, although its worst-case time complexity is the product of the two lengths. To find multiple matches, the expected time is linear in the input lengths, plus the combined length of all the matches, which could be greater than linear. In contrast, the Aho–Corasick algorithm can find all matches of multiple patterns in worst-case time and space linear in the input length and the number of matches (instead of the total length of the matches).

A practical application of the algorithm is detecting plagiarism. Given source material, the algorithm can rapidly search through a paper for instances of sentences from the source material, ignoring details such as case and punctuation. Because of the abundance of the sought strings, single-string searching algorithms are impractical.

🔗 Computing 🔗 Linux

The ASUS Eee PC is a netbook computer line from Asus, and a part of the ASUS Eee product family. At the time of its introduction in late 2007, it was noted for its combination of a lightweight, Linux-based operating system, solid-state drive (SSD), and relatively low cost. Newer models added the options of Microsoft Windows operating system and rotating media hard disk drives (HDD), and initially retailed for up to 500 euros.

The first Eee PC was a milestone in the personal computer business, launching the netbook category of small, low-cost laptops in the West (in Japan, subnotebooks had long been a staple in computing). According to Asus, the name Eee derives from "the three Es", an abbreviation of its advertising slogan for the device: "Easy to learn, Easy to work, Easy to play".

In January 2013, ASUS officially ended production of their Eee PC series, citing declining sales due to consumers favoring tablets and Ultrabooks over netbooks. However, they subsequently restarted the line with the release of the EeeBook series in 2015.

🔗 United States 🔗 Food and drink 🔗 Food and drink/Foodservice

The Pizza Meter refers to sudden increases of pizza orders from U.S. government offices, such as the White House and The Pentagon, before large events such as the Iraqi invasion of Kuwait, the Panama Invasion, and the Grenada invasion.

On the night of August 1, 1990, the night before the Iraqi invasion of Kuwait, military personnel at The Pentagon came together to discuss issues in the Middle East. According to Frank Meeks, the owner of Washington, D.C.'s Domino's Pizza franchise of 45 restaurants, the CIA ordered a record-breaking 21 pizzas from Domino's that night. Between January 7 to January 16, 1991, the number of pizza deliveries to the Pentagon past 10 p.m reached 101, with another 55 pizzas delivered to the White House on January 16 between 10 p.m. and 2 a.m.

Meeks tied the influx of pizza orders from the Pentagon, White House, and the CIA to oncoming major announcements from the White House, publicizing his observations. Consequently, the public nicknamed the event "The Pizza Meter". Shortly after Meeks' comments were released, government offices no longer ordered from Domino's branches in Washington, opting to buy pizza at separate times or at different pizza joints.

🔗 Palaeontology

The cat gap is a period in the fossil record of approximately 25 to 18.5 million years ago in which there are few fossils of cats or cat-like species found in North America. The cause of the "cat gap" is disputed, but may have been caused by changes in the climate (global cooling), changes in the habitat and environmental ecosystem, the increasingly hypercarnivorous trend of the cats (especially the nimravids), volcanic activity, evolutionary changes in dental morphology of the Canidae species present in North America, or a periodicity of extinctions called van der Hammen cycles.

🔗 United States/U.S. Government 🔗 United States 🔗 Politics 🔗 Politics/American politics 🔗 Conservatism 🔗 Elections and Referendums 🔗 United States/U.S. presidential elections 🔗 United States/U.S. history 🔗 United States/Presidents of the United States

The Trump fake electors plot was an attempt by U.S. president Donald Trump and associates to have him remain in power after losing the 2020 United States presidential election. After the results of the election determined Trump had lost, he, his associates, and Republican Party officials in seven battleground states – Arizona, Georgia, Michigan, Nevada, New Mexico, Pennsylvania, and Wisconsin – devised a scheme to submit fraudulent certificates of ascertainment to falsely claim Trump had won the Electoral College vote in crucial states. The plot was one of Trump and his associates' attempts to overturn the 2020 United States presidential election.

The intent of the scheme was to pass the illegitimate certificates to then-Vice President Mike Pence in the hope he would count the fake electoral college ballots, rather than the authentic certificates, and thus overturn Joe Biden's victory. This scheme was defended by a fringe legal theory developed by Trump attorneys Kenneth Chesebro and John Eastman, detailed in the Eastman memos, which claimed a vice president has the constitutional discretion to swap official electors with an alternate slate during the certification process, thus changing the outcome of the electoral college vote and the overall winner of the presidential race. The scheme came to be known as the Pence Card.

By June 2024, dozens of Republican state officials and Trump associates had been indicted in four states for their alleged involvement. The federal Smith special counsel investigation investigated Trump's role in the events. According to testimony, Trump was aware of the fake electors scheme, and knew that Eastman's plan for Pence to obstruct the certification of electoral votes was a violation of the Electoral Count Act.

Trump's personal attorney, Rudy Giuliani, a "central figure" in the plot, coordinated the scheme across the seven states. In a conference call on January 2, 2021, Trump, Eastman, and Giuliani spoke to some 300 Republican state legislators in an effort to persuade them to convene special legislative sessions to replace legitimate Biden electors with fake Trump electors based on unfounded allegations of election fraud. Trump pressured the Justice Department to falsely announce it had found election fraud, and he attempted to install a new acting attorney general who had drafted a letter falsely asserting such election fraud had been found, in an attempt to persuade the Georgia legislature to convene and reconsider its Biden electoral votes.

Trump and Eastman asked Republican National Committee chair Ronna McDaniel to enlist the committee's assistance in gathering fake "contingent" electors. A senator's chief of staff tried to pass a list of fraudulent electors to Pence minutes before the vice president was to certify the election. The scheme was investigated by the January 6 committee and the Justice Department. The January 6 committee's final report identified lawyer Kenneth Chesebro as the plot's original architect. On October 20, 2023, Chesebro pleaded guilty in the state of Georgia to conspiring to file a false document and was sentenced to five years of probation.

🔗 Color

RAL is a colour management system used in Europe that is created and administered by the German RAL gGmbH (RAL non-profit LLC), which is a subsidiary of the German RAL Institute. In colloquial speech, RAL refers to the RAL Classic system, mainly used for varnish and powder coating, but now plastics as well. Approved RAL products are provided with a hologram to make unauthorised versions difficult to produce. Imitations may show different hue and colour when observed under various light sources.

🔗 Mathematics 🔗 Statistics 🔗 Systems 🔗 Robotics 🔗 Systems/Control theory

In statistics and control theory, Kalman filtering, also known as linear quadratic estimation (LQE), is an algorithm that uses a series of measurements observed over time, containing statistical noise and other inaccuracies, and produces estimates of unknown variables that tend to be more accurate than those based on a single measurement alone, by estimating a joint probability distribution over the variables for each timeframe. The filter is named after Rudolf E. Kálmán, one of the primary developers of its theory.

The Kalman filter has numerous applications in technology. A common application is for guidance, navigation, and control of vehicles, particularly aircraft, spacecraft and dynamically positioned ships. Furthermore, the Kalman filter is a widely applied concept in time series analysis used in fields such as signal processing and econometrics. Kalman filters also are one of the main topics in the field of robotic motion planning and control and can be used in trajectory optimization. The Kalman filter also works for modeling the central nervous system's control of movement. Due to the time delay between issuing motor commands and receiving sensory feedback, use of the Kalman filter supports a realistic model for making estimates of the current state of the motor system and issuing updated commands.

The algorithm works in a two-step process. In the prediction step, the Kalman filter produces estimates of the current state variables, along with their uncertainties. Once the outcome of the next measurement (necessarily corrupted with some amount of error, including random noise) is observed, these estimates are updated using a weighted average, with more weight being given to estimates with higher certainty. The algorithm is recursive. It can run in real time, using only the present input measurements and the previously calculated state and its uncertainty matrix; no additional past information is required.

Optimality of the Kalman filter assumes that the errors are Gaussian. In the words of Rudolf E. Kálmán: "In summary, the following assumptions are made about random processes: Physical random phenomena may be thought of as due to primary random sources exciting dynamic systems. The primary sources are assumed to be independent gaussian random processes with zero mean; the dynamic systems will be linear." Though regardless of Gaussianity, if the process and measurement covariances are known, the Kalman filter is the best possible linear estimator in the minimum mean-square-error sense.

Extensions and generalizations to the method have also been developed, such as the extended Kalman filter and the unscented Kalman filter which work on nonlinear systems. The underlying model is a hidden Markov model where the state space of the latent variables is continuous and all latent and observed variables have Gaussian distributions. Also, Kalman filter has been successfully used in multi-sensor fusion, and distributed sensor networks to develop distributed or consensus Kalman filter.

🔗 Computing 🔗 Computer science

In computer science, program synthesis is the task to construct a program that provably satisfies a given high-level formal specification. In contrast to program verification, the program is to be constructed rather than given; however, both fields make use of formal proof techniques, and both comprise approaches of different degrees of automation. In contrast to automatic programming techniques, specifications in program synthesis are usually non-algorithmic statements in an appropriate logical calculus.

The primary application of program synthesis is to relieve the programmer of the burden of writing correct, efficient code that satisfies a specification. However, program synthesis also has applications to superoptimization and inference of loop invariants.

🔗 Biography 🔗 Military history 🔗 Military history/Military biography 🔗 Biography/military biography 🔗 Military history/World War II 🔗 Military history/German military history 🔗 Military history/European military history 🔗 Military history/British military history 🔗 Crime and Criminal Biography 🔗 Jersey

Edward Arnold Chapman (16 November 1914 – 11 December 1997) was an English criminal and wartime spy. During the Second World War he offered his services to Nazi Germany as a spy and subsequently became a British double agent. His British Secret Service handlers codenamed him Agent Zigzag in acknowledgement of his erratic personal history.

He had a number of criminal aliases known by the British police, amongst them Edward Edwards, Arnold Thompson and Edward Simpson. His German codename was Fritz or, later, after endearing himself to his German contacts, its diminutive form of Fritzchen.