Have a deep view into what people are curious about.

🔗 Mathematics

The art gallery problem or museum problem is a well-studied visibility problem in computational geometry. It originates from a real-world problem of guarding an art gallery with the minimum number of guards who together can observe the whole gallery. In the geometric version of the problem, the layout of the art gallery is represented by a simple polygon and each guard is represented by a point in the polygon. A set ${\displaystyle S}$ of points is said to guard a polygon if, for every point ${\displaystyle p}$ in the polygon, there is some ${\displaystyle q\in S}$ such that the line segment between ${\displaystyle p}$ and ${\displaystyle q}$ does not leave the polygon.

🔗 Medicine 🔗 Death 🔗 Countries

The article documents lists of countries by average life expectancy at birth by various sources of estimates.

🔗 Environment

An automated vacuum waste collection system, also known as pneumatic refuse collection, or automated vacuum collection (AVAC), transports waste at high speed through underground pneumatic tubes to a collection station where it is compacted and sealed in containers. When the container is full, it is transported away and emptied. The system helps facilitate separation and recycling of waste.

The process begins with the deposit of trash into intake hatches, called portholes, which may be specialized for waste, recycling, or compost. Portholes are located in public areas and on private property where the owner has opted in. The waste is then pulled through an underground pipeline by air pressure difference created by large industrial fans, in response to porthole sensors that indicate when the trash needs to be emptied and help ensure that only one kind of waste material is travelling through the pipe at a time. The pipelines converge on a central processing facility that uses automated software to direct the waste to the proper container, from there to be trucked to its final location, such as a landfill or composting plant.

🔗 Science Fiction 🔗 Robotics 🔗 Theatre 🔗 Czech Republic

R.U.R. is a 1920 science-fiction play by the Czech writer Karel Čapek. "R.U.R." stands for Rossumovi Univerzální Roboti (Rossum's Universal Robots, a phrase that has been used as a subtitle in English versions). The play had its world premiere on 2 January 1921 in Hradec Králové; it introduced the word "robot" to the English language and to science fiction as a whole. R.U.R. soon became influential after its publication. By 1923 it had been translated into thirty languages. R.U.R. was successful in its time in Europe and North America. Čapek later took a different approach to the same theme in his 1936 novel War with the Newts, in which non-humans become a servant-class in human society.

🔗 Education 🔗 Toys

The Gilbert U-238 Atomic Energy Lab is a toy lab set that was produced by Alfred Carlton Gilbert, who was an American athlete, magician, toy-maker, business man, and inventor of the well-known Erector Set. The Atomic Energy Lab was released by the A. C. Gilbert Company in 1950. The kit's intention was to allow children to create and watch nuclear and chemical reactions using radioactive material.

🔗 Military history 🔗 Military history/North American military history 🔗 Military history/United States military history

Operation Dark Winter was the code name for a senior-level bio-terrorist attack simulation conducted from June 22–23, 2001. It was designed to carry out a mock version of a covert and widespread smallpox attack on the United States. Tara O'Toole and Thomas Inglesby of the Johns Hopkins Center for Civilian Biodefense Strategies (CCBS) / Center for Strategic and International Studies (CSIS), and Randy Larsen and Mark DeMier of Analytic Services were the principal designers, authors, and controllers of the Dark Winter project.

Dark Winter was focused on evaluating the inadequacies of a national emergency response during the use of a biological weapon against the American populace. The exercise was solely intended to establish preventive measures and response strategies by increasing governmental and public awareness of the magnitude and potential of such a threat posed by biological weapons.

Dark Winter's simulated scenario involved an initial localized smallpox attack on Oklahoma City, Oklahoma with additional smallpox attack cases in Georgia and Pennsylvania. The simulation was then designed to spiral out of control. This would create a contingency in which the National Security Council struggles to determine both the origin of the attack as well as deal with containing the spreading virus. By not being able to keep pace with the disease's rate of spread, a new catastrophic contingency emerges in which massive civilian casualties would overwhelm America's emergency response capabilities.

The disastrous contingencies that would result in the massive loss of civilian life were used to exploit the weaknesses of the U.S. health care infrastructure and its inability to handle such a threat. The contingencies were also meant to address the widespread panic that would emerge and which would result in mass social breakdown and mob violence. Exploits would also include the many difficulties that the media would face when providing American citizens with the necessary information regarding safety procedures.

🔗 Spaceflight 🔗 Astronomy

J002E3 is the designation given to an object in space discovered on September 3, 2002, by amateur astronomer Bill Yeung. Initially thought to be an asteroid, it has since been tentatively identified as the S-IVB third stage of the Apollo 12 Saturn V rocket (designated S-IVB-507), based on spectrographic evidence consistent with the titanium dioxide in the paint used on the rockets. The stage was intended to be injected into a permanent heliocentric orbit in November 1969, but is now believed instead to have gone into an unstable high Earth orbit which left Earth's proximity in 1971 and again in June 2003, with an approximately 40-year cycle between heliocentric and geocentric orbit.

🔗 Biography 🔗 Africa 🔗 Japan 🔗 Japan/History 🔗 Japan/Biography

Yasuke (variously rendered as 弥助 or 弥介, 彌助 or 彌介 in different sources) was a man of African origin who served as a retainer under the Japanese daimyō Oda Nobunaga. In 1579, Yasuke arrived in Japan in the service of Italian Jesuit missionary Alessandro Valignano, Visitor of Missions in the Indies, in India.

Yasuke is thought by some to have been the first African that Nobunaga had ever seen and he was one of the many Africans to have come with the Portuguese to Japan during the Nanban trade. He was also present during the Honnō-ji Incident, the forced suicide of Nobunaga at the hands of his samurai general Akechi Mitsuhide on 21 June 1582.