Have a deep view into what people are curious about.

🔗 Time

The Symmetry454 calendar (Sym454) is a proposal for calendar reform created by Irv Bromberg of the University of Toronto, Canada. It is a perennial solar calendar that conserves the traditional month pattern and 7-day week, has symmetrical equal quarters in 82% of the years in its 293-year cycle, and starts every month on Monday.

In computer science and mathematics, a full employment theorem is a term used, often humorously, to refer to a theorem which states that no algorithm can optimally perform a particular task done by some class of professionals. The name arises because such a theorem ensures that there is endless scope to keep discovering new techniques to improve the way at least some specific task is done.

For example, the full employment theorem for compiler writers states that there is no such thing as a provably perfect size-optimizing compiler, as such a proof for the compiler would have to detect non-terminating computations and reduce them to a one-instruction infinite loop. Thus, the existence of a provably perfect size-optimizing compiler would imply a solution to the halting problem, which cannot exist. This also implies that there may always be a better compiler since the proof that one has the best compiler cannot exist. Therefore, compiler writers will always be able to speculate that they have something to improve. A similar example in practical computer science is the idea of no free lunch in search and optimization, which states that no efficient general-purpose solver can exist, and hence there will always be some particular problem whose best known solution might be improved.

Similarly, Gödel's incompleteness theorems have been called full employment theorems for mathematicians. In theoretical computer science this field of study is known as Kolmogorov complexity, or the smallest program which outputs a given string.

Tasks such as virus writing and detection, and spam filtering and filter-breaking are also subject to Rice's theorem.

🔗 Companies 🔗 France 🔗 Automobiles 🔗 Japan 🔗 Japan/Business and economy 🔗 Japan/Car

The Renault–Nissan–Mitsubishi Alliance, originally known as the Renault–Nissan Alliance, is a French-Japanese strategic alliance between the automobile manufacturers Renault (based in Boulogne-Billancourt, France), Nissan (based in Yokohama, Japan) and Mitsubishi Motors (based in Tokyo, Japan), which together sell more than 1 in 9 vehicles worldwide. Renault and Nissan are strategic partners since 1999 and have nearly 450,000 employees and control eight major brands: Renault, Nissan, Mitsubishi, Infiniti, Renault Korea, Dacia, Alpine, and Venucia. The car group sold 10.6 million vehicles worldwide in 2017, making it the leading light vehicle manufacturing group in the world. The Alliance adopted its current name in September 2017, one year after Nissan acquired a controlling interest in Mitsubishi and subsequently made Mitsubishi an equal partner in the Alliance.

As of December 2021, the Alliance is one of the world's leading electric vehicle manufacturing groups, with global sales of over 1 million light-duty electric vehicles since 2009. The top selling vehicles of its EV line-up are the Nissan Leaf and the Renault Zoe all-electric cars.

The strategic partnership between Renault, Nissan and Mitsubishi is not a merger or an acquisition. The three companies are joined through a cross-sharing agreement. The structure was unique in the auto industry during the 1990s consolidation trend and later served as a model for General Motors and the PSA Group, and Mitsubishi, as well as the Volkswagen Group and Suzuki, though the latter combination failed. The Alliance itself has broadened its scope substantially, forming additional partnerships with automakers including Germany's Daimler and China's Dongfeng.

Following the November 2018 arrest and imprisonment of Alliance chairman and CEO Carlos Ghosn, accompanied by his dismissal from the alliance and its components, press analysts have questioned both the stability of the Alliance's shareholding agreement and its long-term existence. These analysts also note that, because the companies' recent business strategies are interdependent, attempts to restructure the Alliance could be counter-productive for all of the members.

In January 2023, Renault and Nissan moved to restructure their alliance in order to recover from Ghosn's arrest and manage through a post-Covid economy. The primary objective was to give both companies more autonomy.

🔗 Computing

The MicroVAX 78032 (otherwise known as the DC333) is a microprocessor developed and fabricated by Digital Equipment Corporation (DEC) that implemented a subset of the VAX instruction set architecture (ISA). The 78032 was used exclusively in DEC's VAX-based systems, starting with the MicroVAX II in 1985. When clocked at a frequency of 5 MHz, the 78032's integer performance is comparable to the original VAX-11/780 of 1977. The microprocessor could be paired with the MicroVAX 78132 floating point accelerator for improved floating point performance.

The 78032 represented a number of firsts for DEC. It was DEC's first single-chip microprocessor implementation of the VAX ISA and DEC's first self-fabricated microprocessor. The MicroVAX 78032 is also notable as it was the first semiconductor device to be registered for protection under the Semiconductor Chip Protection Act of 1984.

The MicroVAX 78032 contains 125,000 transistors on an 8.7 by 8.6 mm (74.82 mm²) die that was fabricated in DEC's ZMOS process, a 3.0 µm NMOS logic process with two layers of aluminum interconnect. The die is packaged in a 68-pin surface-mounted leaded chip carrier.

🔗 United States 🔗 Finance & Investment 🔗 Lists 🔗 Business

This is a list of the largest United States bank failures with respect to total assets under management at the time of the bank failure (banks with $1.0 billion or more in assets are listed here). Assets of the banks listed here are figures provided by the Federal Deposit Insurance Corporation.

🔗 Ships

The Voith Schneider propeller (VSP), also known as a cycloidal drive is a specialized marine propulsion system (MPS). It is highly maneuverable, being able to change the direction of its thrust almost instantaneously. It is widely used on tugs and ferries.

🔗 Arthropods

Carcinisation (or carcinization) is an example of convergent evolution in which a crustacean evolves into a crab-like form from a non-crab-like form. The term was introduced into evolutionary biology by L. A. Borradaile, who described it as "one of the many attempts of Nature to evolve a crab".

🔗 Computer science 🔗 Statistics

The Jaccard index, also known as the Jaccard similarity coefficient, is a statistic used for gauging the similarity and diversity of sample sets. It was developed by Grove Karl Gilbert in 1884 as his ratio of verification (v) and now is frequently referred to as the Critical Success Index in meteorology. It was later developed independently by Paul Jaccard, originally giving the French name coefficient de communauté, and independently formulated again by T. Tanimoto. Thus, the Tanimoto index or Tanimoto coefficient are also used in some fields. However, they are identical in generally taking the ratio of Intersection over Union. The Jaccard coefficient measures similarity between finite sample sets, and is defined as the size of the intersection divided by the size of the union of the sample sets:

${\displaystyle J(A,B)={{|A\cap B|} \over {|A\cup B|}}={{|A\cap B|} \over {|A|+|B|-|A\cap B|}}.}$

Note that by design, ${\displaystyle 0\leq J(A,B)\leq 1.}$ If A intersection B is empty, then J(A,B) = 0. The Jaccard coefficient is widely used in computer science, ecology, genomics, and other sciences, where binary or binarized data are used. Both the exact solution and approximation methods are available for hypothesis testing with the Jaccard coefficient.

Jaccard similarity also applies to bags, i.e., Multisets. This has a similar formula, but the symbols mean bag intersection and bag sum (not union). The maximum value is 1/2.

${\displaystyle J(A,B)={{|A\cap B|} \over {|A\uplus B|}}={{|A\cap B|} \over {|A|+|B|}}.}$

The Jaccard distance, which measures dissimilarity between sample sets, is complementary to the Jaccard coefficient and is obtained by subtracting the Jaccard coefficient from 1, or, equivalently, by dividing the difference of the sizes of the union and the intersection of two sets by the size of the union:

${\displaystyle d_{J}(A,B)=1-J(A,B)={{|A\cup B|-|A\cap B|} \over |A\cup B|}.}$

An alternative interpretation of the Jaccard distance is as the ratio of the size of the symmetric difference ${\displaystyle A\triangle B=(A\cup B)-(A\cap B)}$ to the union. Jaccard distance is commonly used to calculate an n × n matrix for clustering and multidimensional scaling of n sample sets.

This distance is a metric on the collection of all finite sets.

There is also a version of the Jaccard distance for measures, including probability measures. If ${\displaystyle \mu }$ is a measure on a measurable space ${\displaystyle X}$, then we define the Jaccard coefficient by

${\displaystyle J_{\mu }(A,B)={{\mu (A\cap B)} \over {\mu (A\cup B)}},}$

and the Jaccard distance by

${\displaystyle d_{\mu }(A,B)=1-J_{\mu }(A,B)={{\mu (A\triangle B)} \over {\mu (A\cup B)}}.}$

Care must be taken if ${\displaystyle \mu (A\cup B)=0}$ or ${\displaystyle \infty }$, since these formulas are not well defined in these cases.

The MinHash min-wise independent permutations locality sensitive hashing scheme may be used to efficiently compute an accurate estimate of the Jaccard similarity coefficient of pairs of sets, where each set is represented by a constant-sized signature derived from the minimum values of a hash function.

🔗 Computing 🔗 Libraries

"As We May Think" is a 1945 essay by Vannevar Bush which has been described as visionary and influential, anticipating many aspects of information society. It was first published in The Atlantic in July 1945 and republished in an abridged version in September 1945—before and after the atomic bombings of Hiroshima and Nagasaki. Bush expresses his concern for the direction of scientific efforts toward destruction, rather than understanding, and explicates a desire for a sort of collective memory machine with his concept of the memex that would make knowledge more accessible, believing that it would help fix these problems. Through this machine, Bush hoped to transform an information explosion into a knowledge explosion.

🔗 Biography 🔗 Disambiguation

William Adams may refer to: