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🔗 Technology 🔗 Canada 🔗 Guild of Copy Editors 🔗 Engineering

A screw drive is a system used to turn a screw. At a minimum, it is a set of shaped cavities and protrusions on the screw head that allows torque to be applied to it. Usually, it also involves a mating tool, such as a screwdriver, that is used to turn it. The following heads are categorized based on commonality, with some of the less-common drives being classified as "tamper-resistant".

Most heads come in a range of sizes, typically distinguished by a number, such as "Phillips #00". These sizes do not necessarily describe a particular dimension of the drive shape, but rather are arbitrary designations.

🔗 Computing 🔗 Computing/Computer hardware

PLATO (Programmed Logic for Automatic Teaching Operations) was the first generalized computer-assisted instruction system. Starting in 1960, it ran on the University of Illinois' ILLIAC I computer. By the late 1970s, it supported several thousand graphics terminals distributed worldwide, running on nearly a dozen different networked mainframe computers. Many modern concepts in multi-user computing were originally developed on PLATO, including forums, message boards, online testing, e-mail, chat rooms, picture languages, instant messaging, remote screen sharing, and multiplayer video games.

PLATO was designed and built by the University of Illinois and functioned for four decades, offering coursework (elementary through university) to UIUC students, local schools, and other universities. Courses were taught in a range of subjects, including Latin, chemistry, education, music, and primary mathematics. The system included a number of features useful for pedagogy, including text overlaying graphics, contextual assessment of free-text answers, depending on the inclusion of keywords, and feedback designed to respond to alternative answers.

Rights to market PLATO as a commercial product were licensed by Control Data Corporation (CDC), the manufacturer on whose mainframe computers the PLATO IV system was built. CDC President William Norris planned to make PLATO a force in the computer world, but found that marketing the system was not as easy as hoped. PLATO nevertheless built a strong following in certain markets, and the last production PLATO system did not shut down until 2006, coincidentally just a month after Norris died.

🔗 Biography 🔗 Aviation 🔗 France 🔗 Biography/science and academia 🔗 Brazil 🔗 Aviation/aerospace biography 🔗 Brazil/Education and Science in Brazil

Alberto Santos-Dumont (Brazilian Portuguese: [awˈbɛɾtu ˈsɐ̃tus duˈmõ]; 20 July 1873 – 23 July 1932) was a Brazilian inventor and aviation pioneer, one of the very few people to have contributed significantly to the development of both lighter-than-air and heavier-than-air aircraft.

The heir of a wealthy family of coffee producers, Santos-Dumont dedicated himself to aeronautical study and experimentation in Paris, where he spent most of his adult life. In his early career he designed, built, and flew hot air balloons and early dirigibles, culminating in his winning the Deutsch de la Meurthe prize on 19 October 1901 for a flight that rounded the Eiffel Tower. He then turned to heavier-than-air machines, and on 23 October 1906 his 14-bis made the first powered heavier-than-air flight in Europe to be certified by the Aéro-Club de France and the Fédération Aéronautique Internationale. His conviction that aviation would usher in an era of worldwide peace and prosperity led him to freely publish his designs and forego patenting his various innovations.

Santos-Dumont is a national hero in Brazil, where it is popularly held that he preceded the Wright brothers in demonstrating a practical airplane. Countless roads, plazas, schools, monuments, and airports there are dedicated to him, and his name is inscribed on the Tancredo Neves Pantheon of the Fatherland and Freedom. He was a member of the Brazilian Academy of Letters from 1931 until his suicide in 1932.

🔗 Robotics 🔗 Software 🔗 Software/Computing

VxWorks is a real-time operating system (RTOS) developed as proprietary software by Wind River Systems, a wholly owned subsidiary of TPG Capital, US. First released in 1987, VxWorks is designed for use in embedded systems requiring real-time, deterministic performance and, in many cases, safety and security certification, for industries, such as aerospace and defense, medical devices, industrial equipment, robotics, energy, transportation, network infrastructure, automotive, and consumer electronics.

VxWorks supports Intel architecture, POWER architecture, ARM architectures and RISC-V. The RTOS can be used in multicore asymmetric multiprocessing (AMP), symmetric multiprocessing (SMP), and mixed modes and multi-OS (via Type 1 hypervisor) designs on 32- and 64-bit processors.

VxWorks comes with the kernel, middleware, board support packages, Wind River Workbench development suite and complementary third-party software and hardware technologies. In its latest release, VxWorks 7, the RTOS has been re-engineered for modularity and upgradeability so the OS kernel is separate from middleware, applications and other packages. Scalability, security, safety, connectivity, and graphics have been improved to address Internet of Things (IoT) needs.

🔗 Internet 🔗 Computing 🔗 Computing/Computer Security 🔗 Computing/Websites 🔗 Computing/Networking

Domain fronting is a technique for Internet censorship circumvention that uses different domain names in different communication layers of an HTTPS connection to discreetly connect to a different target domain than is discernable to third parties monitoring the requests and connections.

Due to quirks in security certificates, the redirect systems of the content delivery networks (CDNs) used as 'domain fronts', and the protection provided by HTTPS, censors are typically unable to differentiate circumvention ("domain-fronted") traffic from overt non-fronted traffic for any given domain name. As such they are forced to either allow all traffic to the domain front—including circumvention traffic—or block the domain front entirely, which may result in expensive collateral damage and has been likened to "blocking the rest of the Internet".

Domain fronting does not conform to HTTP standards that require the SNI extension and HTTP Host header to contain the same domain. Many large cloud service providers, including Amazon, Microsoft, and Google, actively prohibit domain fronting, which has limited it as a censorship bypass technique. Pressure from censors in Russia and China is thought to have contributed to these prohibitions, but domain fronting can also be used maliciously.

A newer variant of domain fronting, domain hiding, passes an encrypted request for one resource (say, a website), concealed behind an unencrypted (plaintext) request for another resource whose DNS records are stored in the same cloud. It has much the same effect. Refraction networking is an application of the broader principle.

🔗 Mass surveillance 🔗 Computing 🔗 Korea 🔗 Korea/North Korea

Kwangmyong (literally “Bright Light”) is a North Korean "walled garden" national intranet service opened in 2000.

The network uses domain names under the .kp top level domain that are not accessible from the global Internet. As of 2016 the network uses IPv4 addresses reserved for private networks in the 10.0.0.0/8 range. North Koreans often find it more convenient to access sites by their IP address rather than by URL using Latin characters. Like the global Internet, the network hosts content accessible with web browsers, and provides an internal web search engine. It also provides email services and news groups.

Only foreigners and a small number of government officials/scholars/elites are allowed to use the global Internet in North Korea, making Kwangmyong the only computer network available to most North Korean citizens. It is a free service for public use.

🔗 Physics 🔗 Physics/Acoustics

In acoustics, a beat is an interference pattern between two sounds of slightly different frequencies, perceived as a periodic variation in volume whose rate is the difference of the two frequencies.

With tuning instruments that can produce sustained tones, beats can be readily recognized. Tuning two tones to a unison will present a peculiar effect: when the two tones are close in pitch but not identical, the difference in frequency generates the beating. The volume varies like in a tremolo as the sounds alternately interfere constructively and destructively. As the two tones gradually approach unison, the beating slows down and may become so slow as to be imperceptible. As the two tones get further apart, their beat frequency starts to approach the range of human pitch perception, the beating starts to sound like a note, and a combination tone is produced. This combination tone can also be referred to as a missing fundamental, as the beat frequency of any two tones is equivalent to the frequency of their implied fundamental frequency.

🔗 Computer science

The General Purpose Analog Computer (GPAC) is a mathematical model of analog computers first introduced in 1941 by Claude Shannon. This model consists of circuits where several basic units are interconnected in order to compute some function. The GPAC can be implemented in practice through the use of mechanical devices or analog electronics. Although analog computers have fallen almost into oblivion due to emergence of the digital computer, the GPAC has recently been studied as a way to provide evidence for the physical Church–Turing thesis. This is because the GPAC is also known to model a large class of dynamical systems defined with ordinary differential equations, which appear frequently in the context of physics. In particular it was shown in 2007 that (a deterministic variant of) the GPAC is equivalent, in computability terms, to Turing machines, thereby proving the physical Church–Turing thesis for the class of systems modelled by the GPAC. This was recently strengthened to polynomial time equivalence.

🔗 Linguistics 🔗 Linguistics/Etymology

This is a list of etymologies proposed for the word OK or okay. The majority can be easily classified as false etymologies, or possibly folk etymologies. H. L. Mencken, in The American Language, lists serious candidates and "a few of the more picturesque or preposterous". Allen Walker Read surveyed a variety of explanations in a 1964 article titled The Folklore of "O. K." Eric Partridge described O.K. as "an evergreen of the correspondence column."