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🔗 Mathematics

In mathematics and computing, Fibonacci coding is a universal code which encodes positive integers into binary code words. It is one example of representations of integers based on Fibonacci numbers. Each code word ends with "11" and contains no other instances of "11" before the end.

The Fibonacci code is closely related to the Zeckendorf representation, a positional numeral system that uses Zeckendorf's theorem and has the property that no number has a representation with consecutive 1s. The Fibonacci code word for a particular integer is exactly the integer's Zeckendorf representation with the order of its digits reversed and an additional "1" appended to the end.

🔗 Biography 🔗 Military history 🔗 Military history/Military aviation 🔗 Military history/Military biography 🔗 Military history/World War II 🔗 Military history/Russian, Soviet and CIS military history

Ivan Mikhailovich Chisov (Russian: Иван Михайлович Чисов, Ukrainian: Іван Михайлович Чиссов; 1916–1986) was a Soviet Air Force lieutenant who survived a fall of approximately 7,000 meters (23,000 feet). Some references give the spelling of his last name as Chissov (Russian: Чиссов, Ukrainian: Чиссов).

🔗 Mathematics 🔗 Statistics

The Akaike information criterion (AIC) is an estimator of out-of-sample prediction error and thereby relative quality of statistical models for a given set of data. Given a collection of models for the data, AIC estimates the quality of each model, relative to each of the other models. Thus, AIC provides a means for model selection.

AIC is founded on information theory. When a statistical model is used to represent the process that generated the data, the representation will almost never be exact; so some information will be lost by using the model to represent the process. AIC estimates the relative amount of information lost by a given model: the less information a model loses, the higher the quality of that model.

In estimating the amount of information lost by a model, AIC deals with the trade-off between the goodness of fit of the model and the simplicity of the model. In other words, AIC deals with both the risk of overfitting and the risk of underfitting.

The Akaike information criterion is named after the Japanese statistician Hirotugu Akaike, who formulated it. It now forms the basis of a paradigm for the foundations of statistics; as well, it is widely used for statistical inference.

🔗 Statistics 🔗 Sociology

The Anna Karenina principle states that a deficiency in any one of a number of factors dooms an endeavor to failure. Consequently, a successful endeavor (subject to this principle) is one where every possible deficiency has been avoided.

The name of the principle derives from Leo Tolstoy's book Anna Karenina, which begins:

All happy families are alike; each unhappy family is unhappy in its own way.

In other words: happy families share a common set of attributes which lead to happiness, while any of a variety of attributes can cause an unhappy family. This concept has been generalized to apply to several fields of study.

In statistics, the term Anna Karenina principle is used to describe significance tests: there are any number of ways in which a dataset may violate the null hypothesis and only one in which all the assumptions are satisfied.

🔗 Video games

Don't Buy This (also known as Don't Buy This: Five of the Worst Games Ever) is a compilation of video games for the ZX Spectrum released on 1 April 1985. As described on the box, it contains five of the poorest games submitted to publisher Firebird. Instead of rejecting the submissions, they decided to mock the original developers by releasing them together and publicly brand it as "unoriginal" and "awful". Firebird even disowned all their copyright to the game and encouraged buyers to pirate it at will.

Reviews for the game were universally negative, with critics questioning how to critique the game due to its publicity being based on it being a collection of bad games. Despite the negative reception, the game was a commercial success.

🔗 Visual arts

A pointing machine is a measuring tool used by stone sculptors and woodcarvers to accurately copy plaster, clay or wax sculpture models into wood or stone. In essence the device is a pointing needle that can be set to any position and then fixed. It further consists of brass or stainless steel rods and joints which can be placed into any position and then tightened. It is not actually a machine; its name is derived from the Italian macchinetta di punta. The invention of the tool has been ascribed to both the French sculptor and medallist Nicolas-Marie Gatteaux (1751–1832) and to the British sculptor John Bacon (1740–1799). It was later perfected by Canova. However, similar devices were used in ancient times, when the copying of Greek sculptures for the Roman market was a large industry.

🔗 Biography 🔗 Economics 🔗 University of Cambridge

Piero Sraffa (5 August 1898 – 3 September 1983) was an influential Italian economist who served as lecturer of economics at the University of Cambridge. His book Production of Commodities by Means of Commodities is taken as founding the neo-Ricardian school of economics.

🔗 Climate change 🔗 Europe 🔗 Energy

The European super grid is a possible future super grid that would ultimately interconnect the various European countries and the regions around Europe's borders – including North Africa, Kazakhstan, and Turkey – with a high-voltage direct current (HVDC) power grid.

It is envisaged that a European super grid would:

• lower the cost of power in all participating countries by allowing the entire region to share the most efficient power plants;
• pool load variability and power station unreliability, reducing the margin of inefficient spinning reserve and standby that have to be supplied;
• allow for wider use of renewable energy, particularly wind energy, from the concept that "it is always windy somewhere" – in particular it tends to be windy in the summer in North Africa, and windy in the winter in Europe;
• allow wide sharing of the total European hydro power resource, which is about 6 weeks of full load European output;
• decrease Europe's dependence on imported fuels.

🔗 Robotics

An eigenface () is the name given to a set of eigenvectors when used in the computer vision problem of human face recognition. The approach of using eigenfaces for recognition was developed by Sirovich and Kirby (1987) and used by Matthew Turk and Alex Pentland in face classification. The eigenvectors are derived from the covariance matrix of the probability distribution over the high-dimensional vector space of face images. The eigenfaces themselves form a basis set of all images used to construct the covariance matrix. This produces dimension reduction by allowing the smaller set of basis images to represent the original training images. Classification can be achieved by comparing how faces are represented by the basis set.

🔗 United States 🔗 Companies 🔗 Taxation

Companies of the United States with untaxed profits deals with those U.S. companies whose offshore subsidiaries earn profits which are retained in foreign countries to defer paying U.S. corporate tax. The profits of United States corporations are subject to a federal corporate tax rate of 21%. In principle, the tax is payable on all profits of corporations, whether earned domestically or abroad. However, overseas subsidiaries of U.S. corporations are entitled to a tax deferral of profits on active income until repatriated to the U.S., and are regarded as untaxed. When repatriated, the corporations are entitled to a foreign tax credit for taxes (if any) paid in foreign countries.

Retaining such profits offshore may be regarded as a tax strategy. Many corporations have accumulated substantial untaxed profits offshore, especially in countries with low corporate tax rates. In recent years it has been estimated that untaxed profits range from US$1.6 to $2.1 trillion. The Wall Street Journal noted that the "[u]ntaxed foreign earnings are part of a contentious debate over U.S. fiscal policy and tax code." The profits earned abroad and retained there are subject to a foreign exchange risk, besides other financial risks.

The downside of a strategy of retaining profits offshore is that corporations may want or need to pay dividends to shareholders, or to make investments in the United States, besides other reasons. The alternative may be to borrow funds in the U.S., or access the funds retained offshore in the form of inter-company loans.

The Tax Cuts and Jobs Act of 2017 (TCJA) imposed a one time tax on these offshore profits at 8% (non-cash) and 15.5% (cash) respectively. The Act also includes a provision that taxes all foreign profits in the US in the year they are earned ending the ability of US companies to defer paying US tax on unrepatriated earnings.