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🔗 Computing 🔗 Computing/Computer hardware

The Dadda multiplier is a hardware binary multiplier design invented by computer scientist Luigi Dadda in 1965. It uses a selection of full and half adders to sum the partial products in stages (the Dadda tree or Dadda reduction) until two numbers are left. The design is similar to the Wallace multiplier, but the different reduction tree reduces the required number of gates (for all but the smallest operand sizes) and makes it slightly faster (for all operand sizes).

Dadda and Wallace multipliers have the same three steps for two bit strings ${\displaystyle w_{1}}$ and ${\displaystyle w_{2}}$ of lengths ${\displaystyle \ell _{1}}$ and ${\displaystyle \ell _{2}}$ respectively:

1. Multiply (logical AND) each bit of ${\displaystyle w_{1}}$, by each bit of ${\displaystyle w_{2}}$, yielding ${\displaystyle \ell _{1}\cdot \ell _{2}}$ results, grouped by weight in columns
2. Reduce the number of partial products by stages of full and half adders until we are left with at most two bits of each weight.
3. Add the final result with a conventional adder.

As with the Wallace multiplier, the multiplication products of the first step carry different weights reflecting the magnitude of the original bit values in the multiplication. For example, the product of bits ${\displaystyle a_{n}b_{m}}$ has weight ${\displaystyle n+m}$.

Unlike Wallace multipliers that reduce as much as possible on each layer, Dadda multipliers attempt to minimize the number of gates used, as well as input/output delay. Because of this, Dadda multipliers have a less expensive reduction phase, but the final numbers may be a few bits longer, thus requiring slightly bigger adders.

🔗 Telecommunications 🔗 Law Enforcement

Phone cloning is the copying of identity from one cellular device to another.

🔗 Film 🔗 Africa 🔗 Film/American cinema 🔗 Guild of Copy Editors 🔗 Animal rights

Roar is a 1981 American adventure comedy film written, produced, and directed by Noel Marshall. Roar's story follows Hank, a naturalist who lives on a nature preserve in Africa with lions, tigers, and other big cats. When his family visits him, they are instead confronted by the group of animals. The film stars Marshall as Hank and Tippi Hedren as his wife Madeleine, with Melanie Griffith, and Marshall's sons John and Jerry Marshall in supporting roles.

In 1969, while Hedren was filming Satan's Harvest in Mozambique, she and Marshall had occasion to observe a pride of lions move into a recently vacated house, driven by increased poaching. They decided to make a film centered around that theme, bringing rescued big cats into their homes in California and living with them. Filming began in 1976; it was finished after five years. The film was fully completed after 11 years in production.

Roar was not initially released in North America; in 1981, Noel and John Marshall privately released it internationally. It was also acquired by Filmways Pictures and Alpha Films. Despite performing well in Germany and Japan, Roar was a box office failure, grossing $2 million worldwide against a $17 million budget. In 2015, 34 years after the film's original release, it was released in theaters in the United States by Drafthouse Films. Roar's message of protection for African wildlife as well as its animal interactions were praised by critics, but its plot, story, inconsistent tone, dialogue, and editing were criticized.

The cast and crew members of Roar faced dangerous situations during filming; seventy people, including the film's stars, were injured as a result of multiple animal attacks. Flooding from a dam destroyed much of the set and equipment during its production, and the film's budget increased drastically. In 1983, Hedren founded the Roar Foundation and established the Shambala Preserve sanctuary, to house the animals appearing in the film. She also wrote a book, The Cats of Shambala (1985), about many of the film's events. The film has been described as "the most dangerous film ever made" and "the most expensive home movie ever made", and has gained a cult following.

🔗 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.

🔗 United States/U.S. Government 🔗 United States 🔗 Human rights 🔗 Mass surveillance 🔗 Espionage 🔗 United States/FBI

Main Core is the code name of an American governmental database that is believed to have been in existence since the 1980s. It is believed that Main Core is a federal database containing personal and financial data of millions of United States citizens believed to be threats to national security.

🔗 Aviation 🔗 Disaster management 🔗 Aviation/Aviation accident 🔗 Canada 🔗 Aviation/aircraft 🔗 Aviation/gliding 🔗 Canada/History of Canada 🔗 Canada/Manitoba

Air Canada Flight 143 was a Canadian scheduled domestic passenger flight between Montreal and Edmonton that ran out of fuel on July 23, 1983, at an altitude of 41,000 feet (12,000 m), midway through the flight. The crew was able to glide the Boeing 767 aircraft safely to an emergency landing at a former Royal Canadian Air Force base in Gimli, Manitoba, that had been turned into a motor racing track. This unusual aviation incident earned the aircraft the nickname "Gimli Glider".

The subsequent investigation revealed that a combination of company failures, human errors and confusion over unit measures had led to the aircraft being refuelled with insufficient fuel for the planned flight.

🔗 Lists 🔗 Psychology

A list of 'effects' that have been noticed in the field of psychology.

🔗 Computer science

In computer science, the Knuth–Morris–Pratt string-searching algorithm (or KMP algorithm) searches for occurrences of a "word" W within a main "text string" S by employing the observation that when a mismatch occurs, the word itself embodies sufficient information to determine where the next match could begin, thus bypassing re-examination of previously matched characters.

The algorithm was conceived by James H. Morris and independently discovered by Donald Knuth "a few weeks later" from automata theory. Morris and Vaughan Pratt published a technical report in 1970. The three also published the algorithm jointly in 1977. Independently, in 1969, Matiyasevich discovered a similar algorithm, coded by a two-dimensional Turing machine, while studying a string-pattern-matching recognition problem over a binary alphabet. This was the first linear-time algorithm for string matching.

🔗 United States

This is a list of U.S. states and the District of Columbia by annual net migration. The first table lists U.S. states and the District of Columbia by annual net domestic migration, while the second table lists U.S. states and the District of Columbia by annual net international migration. There is a separate table for the U.S. territories. The term net domestic migration describes the total number of people moving to a state from another state minus people moving to another state from that state. The term net international migration describes the total number of people moving to a state from another country minus people moving to another country from that state.

🔗 United States 🔗 Disaster management 🔗 Medicine 🔗 Viruses 🔗 Korea 🔗 COVID-19 🔗 Europe 🔗 China/Chinese history 🔗 Iran 🔗 North America 🔗 Medicine/Pulmonology 🔗 Italy 🔗 China 🔗 East Asia

The 2019–20 coronavirus pandemic is an ongoing pandemic of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The outbreak was first identified in Wuhan, Hubei, China, in December 2019, and was recognized as a pandemic by the World Health Organization (WHO) on 11 March. As of 28 March 2020, more than 663,000 cases of COVID-19 have been reported in over 190 countries and territories, resulting in approximately 30,800 deaths. More than 141,000 people have since recovered.

The virus is mainly spread during close contact and via respiratory droplets produced when people cough or sneeze. Respiratory droplets may be produced during breathing but the virus is not considered airborne. People may also catch COVID-19 by touching a contaminated surface and then their face. It is most contagious when people are symptomatic, although spread may be possible before symptoms appear. The time between exposure and symptom onset is typically around five days, but may range from 2 to 14 days. Common symptoms include fever, cough, and shortness of breath. Complications may include pneumonia and acute respiratory distress syndrome. There is no known vaccine or specific antiviral treatment. Primary treatment is symptomatic and supportive therapy. Recommended preventive measures include hand washing, covering one's mouth when coughing, maintaining distance from other people, and monitoring and self-isolation for people who suspect they are infected.

Efforts to prevent the virus spreading include travel restrictions, quarantines, curfews, workplace hazard controls, event postponements and cancellations, and facility closures. These include the quarantine of Hubei, national or regional quarantines elsewhere in the world, curfew measures in China and South Korea, various border closures or incoming passenger restrictions, screening at airports and train stations, and outgoing passenger travel bans. Schools and universities have closed either on a nationwide or local basis in more than 160 countries, affecting more than 1.5 billion students.

The pandemic has led to severe global socioeconomic disruption, the postponement or cancellation of sporting, religious, and cultural events, and widespread fears of supply shortages which have spurred panic buying. Misinformation and conspiracy theories about the virus have spread online, and there have been incidents of xenophobia and racism against Chinese and other East and Southeast Asian people.