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๐ Rambus DRAM (Rdram)
Rambus DRAM (RDRAM), and its successors Concurrent Rambus DRAM (CRDRAM) and Direct Rambus DRAM (DRDRAM), are types of synchronous dynamic random-access memory (SDRAM) developed by Rambus from the 1990s through to the early 2000s. The third-generation of Rambus DRAM, DRDRAM was replaced by XDR DRAM. Rambus DRAM was developed for high-bandwidth applications and was positioned by Rambus as replacement for various types of contemporary memories, such as SDRAM. RDRAM is a serial memory bus.
DRDRAM was initially expected to become the standard in PC memory, especially after Intel agreed to license the Rambus technology for use with its future chipsets. Further, DRDRAM was expected to become a standard for graphics memory. However, RDRAM got embroiled in a standards war with an alternative technologyโDDR SDRAMโand quickly lost out on grounds of price and, later, performance. By around 2003, DRDRAM was no longer supported in new personal computers.
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- "Rambus DRAM (Rdram)" | 2024-12-29 | 10 Upvotes 1 Comments
๐ Mr. Big (Police Procedure)
Mr. Big (sometimes known as the Canadian technique) is a covert investigation procedure used by undercover police to elicit confessions from suspects in cold cases (usually murder). Police officers create a fictitious grey area or criminal organization and then seduce the suspect into joining it. They build a relationship with the suspect, gain their confidence, and then enlist their help in a succession of criminal acts (e.g., delivering goods, credit card scams, selling guns) for which they are paid. Once the suspect has become enmeshed in the criminal gang, they are persuaded to divulge information about their criminal history, usually as a prerequisite for being accepted as a member of the organization.
The Mr. Big technique was developed by the Royal Canadian Mounted Police (RCMP) in British Columbia, with the first documented case taking place in March of 1965 during the investigation of David Louis Harrison, a former Vancouver police constable who was tried and convicted for taking part in the robbery of $1.2 million of cancelled currency from the Canadian Pacific Merchandise Services warehouse in Vancouver. Harrison was convicted using evidence gained by Cpl. Allan Richards, posing as crime syndicate hoodlum John Clarke, and his sting partner, police operative Al Brooks. Harrison testified that he believed John Clarke was a violent syndicate hoodlum. Harrison further testified that Clarke was often packing a gun, that Clarke carried a vial of nitroglycerine around his neck that he would throw at a police car if it got too close to him, and that he was afraid he would be harmed if he didnโt play along.
The Mr. Big tactic has been used in more than 350 cases across Canada as of 2008. The RCMP claims that the person of interest was either cleared or charged in 75% of cases (the rest remaining unresolved and requiring further investigation). Of the cases prosecuted, an estimated 95% result in a conviction.
The use of this technique is essentially prohibited in some countries, including the United Kingdom and the United States. In Germany, which has high standards for what constitutes a voluntary confession, it may be more difficult to use confessions obtained by this technique. The procedure has been used by police in Australia and New Zealand, and its use has been upheld by courts in both countries.
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- "Mr. Big (Police Procedure)" | 2026-06-25 | 11 Upvotes 1 Comments
๐ HP Saturn
The Saturn family of 4-bit (datapath) microprocessors was developed by Hewlett-Packard in the 1980s first for the HP-71B handheld computer and then later for various HP calculators (starting with the HP-18C). It succeeded the Nut family of processors used in earlier calculators. The original Saturn chip was first used in the HP-71B hand-held BASIC-programmable computer, introduced in 1984. Later models of the family powered the popular HP 48 series of calculators. The HP48SX and HP48S were the last models to use genuine Saturn processors manufactured by HP. Later calculator models used Saturn processors manufactured by NEC. The HP 49 series initially used the Saturn CPU as well, until the NEC fab could no longer manufacture the processor for technical reasons in 2003. Therefore, starting with the HP 49g+ model in 2003, the calculators switched to a Samsung S3C2410 processor with an ARM920T core (part of the ARMv4T architecture) which ran an emulator of the Saturn hardware in software. In 2000, the HP 39G and HP 40G were the last calculators introduced based on the actual NEC fabricated Saturn hardware. The last calculators based on the Saturn emulator were the HP 39gs, HP 40gs and HP 50g in 2006, as well as the 2007 revision of the hp 48gII. The HP 50g, the last calculator utilizing this emulator, was discontinued in 2015 when Samsung stopped producing the ARM processor on which it was based.
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- "HP Saturn" | 2022-09-21 | 141 Upvotes 73 Comments
๐ Shavarsh Karapetyan
Shavarsh Vladimiri (Vladimirovich) Karapetyan (Armenian: ีีกีพีกึีท ิฟีกึีกีบีฅีฟีตีกีถ; born May 19, 1953) is a retired former Soviet finswimmer, best known for saving the lives of 20 people in a 1976 incident in Yerevan.
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- "Shavarsh Karapetyan" | 2025-01-10 | 204 Upvotes 24 Comments
๐ Itรด Calculus
Itรด calculus, named after Kiyosi Itรด, extends the methods of calculus to stochastic processes such as Brownian motion (see Wiener process). It has important applications in mathematical finance and stochastic differential equations.
The central concept is the Itรด stochastic integral, a stochastic generalization of the RiemannโStieltjes integral in analysis. The integrands and the integrators are now stochastic processes:
where H is a locally square-integrable process adapted to the filtration generated by X (Revuz & Yor 1999, Chapter IV), which is a Brownian motion or, more generally, a semimartingale. The result of the integration is then another stochastic process. Concretely, the integral from 0 to any particular t is a random variable, defined as a limit of a certain sequence of random variables. The paths of Brownian motion fail to satisfy the requirements to be able to apply the standard techniques of calculus. So with the integrand a stochastic process, the Itรด stochastic integral amounts to an integral with respect to a function which is not differentiable at any point and has infinite variation over every time interval. The main insight is that the integral can be defined as long as the integrand H is adapted, which loosely speaking means that its value at time t can only depend on information available up until this time. Roughly speaking, one chooses a sequence of partitions of the interval from 0 to t and constructs Riemann sums. Every time we are computing a Riemann sum, we are using a particular instantiation of the integrator. It is crucial which point in each of the small intervals is used to compute the value of the function. The limit then is taken in probability as the mesh of the partition is going to zero. Numerous technical details have to be taken care of to show that this limit exists and is independent of the particular sequence of partitions. Typically, the left end of the interval is used.
Important results of Itรด calculus include the integration by parts formula and Itรด's lemma, which is a change of variables formula. These differ from the formulas of standard calculus, due to quadratic variation terms.
In mathematical finance, the described evaluation strategy of the integral is conceptualized as that we are first deciding what to do, then observing the change in the prices. The integrand is how much stock we hold, the integrator represents the movement of the prices, and the integral is how much money we have in total including what our stock is worth, at any given moment. The prices of stocks and other traded financial assets can be modeled by stochastic processes such as Brownian motion or, more often, geometric Brownian motion (see BlackโScholes). Then, the Itรด stochastic integral represents the payoff of a continuous-time trading strategy consisting of holding an amount Ht of the stock at time t. In this situation, the condition that H is adapted corresponds to the necessary restriction that the trading strategy can only make use of the available information at any time. This prevents the possibility of unlimited gains through clairvoyance: buying the stock just before each uptick in the market and selling before each downtick. Similarly, the condition that H is adapted implies that the stochastic integral will not diverge when calculated as a limit of Riemann sums (Revuz & Yor 1999, Chapter IV).
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- "Itรด Calculus" | 2023-08-03 | 22 Upvotes 3 Comments
๐ Emo Killings in Iraq
The emo killings in Iraq were a string of homicides that were part of a campaign against Iraqi teenage boys who dressed in a Westernized emo style. Between 6 and 70 young men were kidnapped, tortured and murdered in Baghdad and Iraq during March 2012. In September 2012, BBC News reported that gay men in Baghdad said the killings had not abated.
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- "Emo Killings in Iraq" | 2021-03-31 | 26 Upvotes 4 Comments
๐ The court case that allowed us to connect to the phone network
Hush-A-Phone v. United States, 238 F.2d 266 (D.C. Cir. 1956) was a seminal ruling in United States telecommunications decided by the D.C. Circuit Court of Appeals. Hush-A-Phone Corporation marketed a small, cup-like device which mounted on the speaking party's microphone, reducing the risk of conversations being overheard and increasing sound fidelity for the listening party. At the time, AT&T had a near-monopoly on America's phone system, even controlling the equipment attached to its network. In this era, Americans had to lease equipment from "Ma Bell" or use approved devices. At this time Hush-A-Phone had been around for 20 years without any issues. However, when an AT&T lawyer saw one in a store window, the company decided to sue on the grounds that anything attached to a phone could damage their network.
AT&T, citing the Communications Act of 1934, which stated in part that the company had the right to make changes and dictate "the classifications, practices, and regulations affecting such charges," claimed the right to "forbid attachment to the telephone of any device 'not furnished by the telephone company.'"
Initially, the Federal Communications Commission (FCC) ruled in AT&T's favor. It found that the device was a "foreign attachment" subject to AT&T control and that unrestricted use of the device could, in the commission's opinion, result in a general deterioration of the quality of telephone service.
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- "The court case that allowed us to connect to the phone network" | 2024-02-22 | 15 Upvotes 2 Comments
๐ Wardenclyffe Tower a.k.a. the Tesla Tower
Wardenclyffe Tower (1901โ1917), also known as the Tesla Tower, was an early experimental wireless transmission station designed and built by Nikola Tesla in Shoreham, New York in 1901โ1902. Tesla intended to transmit messages, telephony and even facsimile images across the Atlantic to England and to ships at sea based on his theories of using the Earth to conduct the signals. His decision to scale up the facility and add his ideas of wireless power transmission to better compete with Guglielmo Marconi's radio based telegraph system was met with refusal to fund the changes by the project's primary backer, financier J. P. Morgan. Additional investment could not be found, and the project was abandoned in 1906, never to become operational.
In an attempt to satisfy Tesla's debts, the tower was demolished for scrap in 1917 and the property taken in foreclosure in 1922. For 50 years, Wardenclyffe was a processing facility producing photography supplies. Many buildings were added to the site and the land it occupies has been trimmed down to 16 acres (6.5ย ha) but the original, 94 by 94ย ft (29 by 29ย m), brick building designed by Stanford White remains standing to this day.
In the 1980s and 2000s, hazardous waste from the photographic era was cleaned up, and the site was sold and cleared for new development. A grassroots campaign to save the site succeeded in purchasing the property in 2013, with plans to build a future museum dedicated to Nikola Tesla. In 2018 the property was listed on the National Register of Historic Places.
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- "Wardenclyffe Tower a.k.a. the Tesla Tower" | 2011-01-28 | 10 Upvotes 1 Comments
๐ Third Pole
The Third Pole, also known as the Hindu Kush-Karakoram-Himalayan system (HKKH), is a mountainous region located in the west and south of the Tibetan Plateau. Part of High-Mountain Asia, it spreads over an area of more than 4.2ย million square kilometres (1.6ย million square miles) across nine countries, i.e. Afghanistan, Bangladesh, Bhutan, China, India, Myanmar, Nepal, Pakistan and Tajikistan, bordering ten countries. The area is nicknamed the "Third Pole" because its mountain glaciers and snowfields store more frozen water than anywhere else in the world after the Arctic and Antarctic polar caps. With the world's loftiest mountains, comprising all 14 peaks above 8,000 metres (26,000ย ft), it is the source of 10 major rivers and forms a global ecological buffer.
The Third Pole area is rich with natural resources and consists of all or some of four global biodiversity hotspots. The mountain resources administer a wide range of ecosystem benefits and are the base for the drinking water, food production and livelihoods of the 220 million inhabitants of the region, as well as indirectly to the 1.5 billion people โ one sixth of the world's population โ living in the downstream river basins. Billions of people benefit from the food and energy produced in these river basins whose headwaters rely on meltwaters and precipitations that run off these mountains.
๐ Jackson structured programming
Jackson structured programming (JSP) is a method for structured programming developed by British software consultant Michael A. Jackson and described in his 1975 book Principles of Program Design. The technique of JSP is to analyze the data structures of the files that a program must read as input and produce as output, and then produce a program design based on those data structures, so that the program control structure handles those data structures in a natural and intuitive way.
JSP describes structures (of both data and programs) using three basic structures โ sequence, iteration, and selection (or alternatives). These structures are diagrammed as (in effect) a visual representation of a regular expression.
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- "Jackson structured programming" | 2021-08-12 | 106 Upvotes 69 Comments