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🔗 Aviation 🔗 Disaster management 🔗 Aviation/Aviation accident 🔗 Syria

Syrian Air Flight 9218 was a cargo flight operated by Syrian Air that disappeared from flight tracking near Homs while flying out of Damascus International Airport on December 8, 2024.

🔗 Trains

The symmetry minute is a significant time point in the clock face timetables used by many public transport operators. At this point in the cycle, a train in a clock-face timetable meets its counterpart travelling in the opposite direction on the same line. If this crossing time is constant across a network, connecting times between lines are kept consistent in both directions.

At the symmetry time, the timetable is mirrored in both directions. At the ends of the line, the center of the turnaround time coincides with the symmetry minute. The distance between two consecutive symmetry times is equal to half the cycle time, so on an hourly schedule, opposite trains on the same line cross every 30 minutes. On a two-hour cycle, there is a symmetry time every hour.

In principle, a train-encounter can be set at any time. However, at the transition between two networks or lines, it is expedient to set uniform symmetry minutes, to create a symmetrical connection relation. For the long-distance cycle systems of ÖBB and SBB, the Forschungsgesellschaft für Straßen- und Verkehrswesen für Deutschland (Research Association for Roads and Traffic for Germany) recommends minute 58, so a four-minute minimum connecting time results in a departure at minute 0. Meanwhile, most railways in Central Europe and a number of other transport operators have established the symmetry minute 58½, for a three-minute hold time before a departure at minute 0. Shorter cycles have additional symmetry minutes, shifted by half the cycle time. So an hourly cycle has symmetries at minutes 28½ and 58½, a 30-minute cycle has symmetries at minutes 13½, 28½, 43½ and 58½, and so on.

The following table shows the departure times in opposite directions for an hourly cycle, using the 58½ symmetry minute (the most common in Central Europe). The other departure times for shorter cycles can be calculated from it. The last line gives the meeting times.

🔗 United States/U.S. Government 🔗 United States 🔗 Technology 🔗 Computing 🔗 Systems 🔗 Cognitive science 🔗 Linguistics 🔗 Computing/Computer science 🔗 Robotics 🔗 Transhumanism 🔗 Linguistics/Applied Linguistics 🔗 Systems/Cybernetics

In the history of artificial intelligence, an AI winter is a period of reduced funding and interest in artificial intelligence research. The term was coined by analogy to the idea of a nuclear winter. The field has experienced several hype cycles, followed by disappointment and criticism, followed by funding cuts, followed by renewed interest years or decades later.

The term first appeared in 1984 as the topic of a public debate at the annual meeting of AAAI (then called the "American Association of Artificial Intelligence"). It is a chain reaction that begins with pessimism in the AI community, followed by pessimism in the press, followed by a severe cutback in funding, followed by the end of serious research. At the meeting, Roger Schank and Marvin Minsky—two leading AI researchers who had survived the "winter" of the 1970s—warned the business community that enthusiasm for AI had spiraled out of control in the 1980s and that disappointment would certainly follow. Three years later, the billion-dollar AI industry began to collapse.

Hype is common in many emerging technologies, such as the railway mania or the dot-com bubble. The AI winter was a result of such hype, due to over-inflated promises by developers, unnaturally high expectations from end-users, and extensive promotion in the media . Despite the rise and fall of AI's reputation, it has continued to develop new and successful technologies. AI researcher Rodney Brooks would complain in 2002 that "there's this stupid myth out there that AI has failed, but AI is around you every second of the day." In 2005, Ray Kurzweil agreed: "Many observers still think that the AI winter was the end of the story and that nothing since has come of the AI field. Yet today many thousands of AI applications are deeply embedded in the infrastructure of every industry."

Enthusiasm and optimism about AI has increased since its low point in the early 1990s. Beginning about 2012, interest in artificial intelligence (and especially the sub-field of machine learning) from the research and corporate communities led to a dramatic increase in funding and investment.

🔗 Politics 🔗 Sociology

Sayre's law states, in a formulation quoted by Charles Philip Issawi: "In any dispute the intensity of feeling is inversely proportional to the value of the issues at stake." By way of corollary, it adds: "That is why academic politics are so bitter." Sayre's law is named after Wallace Stanley Sayre (1905–1972), U.S. political scientist and professor at Columbia University.

🔗 Neuroscience 🔗 Anatomy 🔗 Anatomy/Neuroanatomy

Yakovlevian torque (also known as occipital bending (OB) or counterclockwise brain torque) is the tendency of the right side of the human brain to be warped slightly forward relative to the left and the left side of the human brain to be warped slightly backward relative to the right. This is responsible for certain asymmetries, such as how the lateral sulcus of the human brain is often longer and less curved on the left side of the brain relative to the right. Stated in another way, Yakovlevian Torque can be defined by the existence of right-frontal and left-occipital petalias, which are protrusions of the surface of one hemisphere relative to the other. It is named for Paul Ivan Yakovlev (1894–1983), a Russian-American neuroanatomist from Harvard Medical School.

🔗 Computing 🔗 Computing/Software 🔗 Computing/Computer science

Wirth's law is an adage on computer performance which states that software is getting slower more rapidly than hardware is becoming faster.

The adage is named after Niklaus Wirth, who discussed it in his 1995 article "A Plea for Lean Software".

🔗 Aviation 🔗 Military history 🔗 Military history/Military aviation 🔗 Military history/North American military history 🔗 Military history/United States military history 🔗 Aviation/aircraft 🔗 Aviation/aircraft engine

The Aircraft Nuclear Propulsion (ANP) program and the preceding Nuclear Energy for the Propulsion of Aircraft (NEPA) project worked to develop a nuclear propulsion system for aircraft. The United States Army Air Forces initiated Project NEPA on May 28, 1946. NEPA operated until May 1951, when the project was transferred to the joint Atomic Energy Commission (AEC)/USAF ANP. The USAF pursued two different systems for nuclear-powered jet engines, the Direct Air Cycle concept, which was developed by General Electric, and Indirect Air Cycle, which was assigned to Pratt & Whitney. The program was intended to develop and test the Convair X-6, but was cancelled in 1961 before that aircraft was built. The total cost of the program from 1946 to 1961 was about $1 billion.

🔗 Typography

Tiresias is a family of TrueType sans-serif typefaces that were designed with the aim of legibility by people with impaired vision at the Scientific Research Unit of Royal National Institute of Blind People in London. The font was originally designed for the RNIB by Chris Sharville of Laker Sharville Design Associates who was working with John Gill at the time.

The family includes

• Tiresias Infofont – for information labels, optimized for maximum legibility at a distance of 30–100 cm.
• Tiresias Keyfont – for labeling the tops of keys of keyboards, PIN pads, appliances, remote controls (features exaggerated punctuation marks, no descender on the J)
• Tiresias LPfont – for large-print publications. A wedge-serif design.
• Tiresias PCfont – for raster displays
• Tiresias Screenfont – for television subtitling and on-screen user interfaces
• Tiresias Signfont – a more open spacing for use on signs

In late 2007, all Tiresias fonts except Tiresias Screenfont were released under the GNU General Public License version 3 or any later version.

The Tiresias Screenfont was sold by Bitstream Inc., who in 2012 were acquired by Monotype Corporation. The acquiring company continues to market Tiresias on its websites.

🔗 Typography

In typography, an asterism, ⁂, is a typographic symbol consisting of three asterisks placed in a triangle, which is used for a variety of purposes. The name originates from the astronomical term for a group of stars.

The asterism was originally used as a type of dinkus in typography, though increasingly rarely. It can also be used to mean "untitled" or author or title withheld – as seen, for example, in some editions of Album for the Young by composer Robert Schumann (№ 21, 26, and 30). In meteorology, an asterism in a station model indicates moderate snowfall.

🔗 Computing

Simula is the name of two simulation programming languages, Simula I and Simula 67, developed in the 1960s at the Norwegian Computing Center in Oslo, by Ole-Johan Dahl and Kristen Nygaard. Syntactically, it is a fairly faithful superset of ALGOL 60, also influenced by the design of Simscript.

Simula 67 introduced objects, classes, inheritance and subclasses, virtual procedures, coroutines, and discrete event simulation, and features garbage collection. Also other forms of subtyping (besides inheriting subclasses) were introduced in Simula derivatives.

Simula is considered the first object-oriented programming language. As its name suggests, the first Simula version by 1962 was designed for doing simulations; Simula 67 though was designed to be a general-purpose programming language and provided the framework for many of the features of object-oriented languages today.

Simula has been used in a wide range of applications such as simulating very-large-scale integration (VLSI) designs, process modeling, communication protocols, algorithms, and other applications such as typesetting, computer graphics, and education. The influence of Simula is often understated, and Simula-type objects are reimplemented in C++, Object Pascal, Java, C#, and many other languages. Computer scientists such as Bjarne Stroustrup, creator of C++, and James Gosling, creator of Java, have acknowledged Simula as a major influence.