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π Father of the PDP-1: The TX-0, Transistorized EXperimental Computer Zero (1956)
The TX-0, for Transistorized Experimental computer zero, but affectionately referred to as tixo (pronounced "tix oh"), was an early fully transistorized computer and contained a then-huge 64K of 18-bit words of magnetic core memory. Construction of the TX-0 began in 1955 and ended in 1956. It was used continually through the 1960s at MIT. The TX-0 incorporated around 3600 Philco high-frequency surface-barrier transistors, the first transistor suitable for high-speed computers. The TX-0 and its direct descendant, the original PDP-1, were platforms for pioneering computer research and the development of what would later be called computer "hacker" culture.
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- "Father of the PDP-1: The TX-0, Transistorized EXperimental Computer Zero (1956)" | 2021-02-28 | 30 Upvotes 12 Comments
π Eigenface
An eigenface () is the name given to a set of eigenvectors when used in the computer vision problem of human face recognition. The approach of using eigenfaces for recognition was developed by Sirovich and Kirby (1987) and used by Matthew Turk and Alex Pentland in face classification. The eigenvectors are derived from the covariance matrix of the probability distribution over the high-dimensional vector space of face images. The eigenfaces themselves form a basis set of all images used to construct the covariance matrix. This produces dimension reduction by allowing the smaller set of basis images to represent the original training images. Classification can be achieved by comparing how faces are represented by the basis set.
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- "Eigenface" | 2010-01-27 | 26 Upvotes 4 Comments
π Chicago Tunnel and Reservoir Plan
The Tunnel and Reservoir Plan (abbreviated TARP and more commonly known as the Deep Tunnel Project or the Chicago Deep Tunnel) is a large civil engineering project that aims to reduce flooding in the metropolitan Chicago area, and to reduce the harmful effects of flushing raw sewage into Lake Michigan by diverting storm water and sewage into temporary holding reservoirs. The megaproject is one of the largest civil engineering projects ever undertaken in terms of scope, cost and timeframe. Commissioned in the mid-1970s, the project is managed by the Metropolitan Water Reclamation District of Greater Chicago. Completion of the system is not anticipated until 2029, but substantial portions of the system have already opened and are currently operational. Across 30 years of construction, over $3 billion has been spent on the project.
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- "Chicago Tunnel and Reservoir Plan" | 2015-12-04 | 14 Upvotes 5 Comments
π Ytterby
Ytterby (Swedish pronunciation: [ΛΚΜtΛΙrΛbyΛ]) is a village on the Swedish island of ResarΓΆ, in Vaxholm Municipality in the Stockholm archipelago. Today the residential area is dominated by suburban homes.
The Swedish name of the village translates literally into "outer village". Ytterby is the single richest source of elemental discoveries in the world; the chemical elements yttrium (Y), terbium (Tb), erbium (Er), and ytterbium (Yb) are all named after Ytterby, and the elements holmium (Ho), scandium (Sc), thulium (Tm), tantalum (Ta), and gadolinium (Gd) were also first discovered there.
Local roads connect Ytterby to county road 274 and hence the mainland. Except for the winter months, passenger ships of the Waxholmsbolaget call at a pier in Ytterby, providing a connection to Vaxholm town and Stockholm. Ytterby is as well served by several local bus lines of the north east SL district, connecting the area directly to Stockholms Γstra station.
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- "Ytterby" | 2025-10-03 | 32 Upvotes 3 Comments
π Argumentation Theory
Argumentation theory is the interdisciplinary study of how conclusions can be supported or undermined by premises through logical reasoning. With historical origins in logic, dialectic, and rhetoric, argumentation theory includes the arts and sciences of civil debate, dialogue, conversation, and persuasion. It studies rules of inference, logic, and procedural rules in both artificial and real-world settings.
Argumentation includes various forms of dialogue such as deliberation and negotiation which are concerned with collaborative decision-making procedures. It also encompasses eristic dialogue, the branch of social debate in which victory over an opponent is the primary goal, and didactic dialogue used for teaching. This discipline also studies the means by which people can express and rationally resolve or at least manage their disagreements.
Argumentation is a daily occurrence, such as in public debate, science, and law. For example in law, in courts by the judge, the parties and the prosecutor, in presenting and testing the validity of evidences. Also, argumentation scholars study the post hoc rationalizations by which organizational actors try to justify decisions they have made irrationally.
Argumentation is one of four rhetorical modes (also known as modes of discourse), along with exposition, description, and narration.
π Ulam Spiral
The Ulam spiral or prime spiral is a graphical depiction of the set of prime numbers, devised by mathematician StanisΕaw Ulam in 1963 and popularized in Martin Gardner's Mathematical Games column in Scientific American a short time later. It is constructed by writing the positive integers in a square spiral and specially marking the prime numbers.
Ulam and Gardner emphasized the striking appearance in the spiral of prominent diagonal, horizontal, and vertical lines containing large numbers of primes. Both Ulam and Gardner noted that the existence of such prominent lines is not unexpected, as lines in the spiral correspond to quadratic polynomials, and certain such polynomials, such as Euler's prime-generating polynomial x2βββxβ+β41, are believed to produce a high density of prime numbers. Nevertheless, the Ulam spiral is connected with major unsolved problems in number theory such as Landau's problems. In particular, no quadratic polynomial has ever been proved to generate infinitely many primes, much less to have a high asymptotic density of them, although there is a well-supported conjecture as to what that asymptotic density should be.
In 1932, more than thirty years prior to Ulam's discovery, the herpetologist Laurence Klauber constructed a triangular, non-spiral array containing vertical and diagonal lines exhibiting a similar concentration of prime numbers. Like Ulam, Klauber noted the connection with prime-generating polynomials, such as Euler's.
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- "Ulam Spiral" | 2021-08-06 | 64 Upvotes 19 Comments
- "Ulam Spiral" | 2016-06-06 | 71 Upvotes 13 Comments
- "Ulam spiral" | 2013-11-09 | 90 Upvotes 27 Comments
π Greta Thunberg
Greta Tintin Eleonora Ernman Thunberg (Swedish:Β [ΛΙ‘rΓͺΛta ΛtΚΜΛnbΓ¦rj] (listen); born 3 January 2003) is a Swedish environmental activist who has gained international recognition for promoting the view that humanity is facing an existential crisis arising from climate change. Thunberg is known for her youth and her straightforward speaking manner, both in public and to political leaders and assemblies, in which she criticizes world leaders for their failure to take sufficient action to address the climate crisis.
Thunberg's activism started after convincing her parents to adopt several lifestyle choices to reduce their own carbon footprint. In August 2018, at age 15, she started spending her school days outside the Swedish parliament to call for stronger action on climate change by holding up a sign reading Skolstrejk fΓΆr klimatet (School strike for climate). Soon, other students engaged in similar protests in their own communities. Together, they organised a school climate strike movement under the name Fridays for Future. After Thunberg addressed the 2018 United Nations Climate Change Conference, student strikes took place every week somewhere in the world. In 2019, there were multiple coordinated multi-city protests involving over a million students each. To avoid flying, Thunberg sailed to North America where she attended the 2019 UN Climate Action Summit. Her speech there, in which she exclaimed "how dare you", was widely taken up by the press and incorporated into music.
Her sudden rise to world fame has made her both a leader and a target for critics. Her influence on the world stage has been described by The Guardian and other newspapers as the "Greta effect". She has received numerous honours and awards including: honorary Fellowship of the Royal Scottish Geographical Society; Time magazine's 100 most influential people and the youngest Time Person of the Year; inclusion in the Forbes list of The World's 100 Most Powerful Women (2019) and two consecutive nominations for the Nobel Peace Prize (2019 and 2020).
Discussed on
- "Greta Thunberg" | 2019-05-26 | 32 Upvotes 18 Comments
π Eazel, ex-Apple led Linux startup
Eazel was an American software company operating from 1999 to 2001 in Palo Alto and then Mountain View, California. The company's flagship product is the Nautilus file manager for the GNOME desktop environment on Linux, which was immediately adopted and maintained by the free software movement. As the core of Eazel's business model, it is an early example of cloud storage services in the form of personal file storage, transparently and portably stored on the Internet. Renamed to Files, this application continues to be a centerpiece of some free Linux-based desktop environments.
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- "Eazel, ex-Apple led Linux startup" | 2024-08-27 | 147 Upvotes 65 Comments
π The Population Bomb (1968)
The Population Bomb is a 1968 book co-authored by former Stanford University professor Paul R. Ehrlich and former Stanford senior researcher in conservation biology Anne H. Ehrlich. From the opening page, it predicted worldwide famines due to overpopulation, as well as other major societal upheavals, and advocated immediate action to limit population growth. Fears of a "population explosion" existed in the mid-20th century baby boom years, but the book and its authors brought the idea to an even wider audience.
The book has been criticized since its publication for an alarmist tone, and over the subsequent decades, for inaccurate assertions and failed predictions. For instance, regional famines have occurred since the publication of the book, but not world famines. The Ehrlichs themselves still stand by the book despite the flaws identified by its critics, with Paul stating in 2009 that "perhaps the most serious flaw in The Bomb was that it was much too optimistic about the future," despite having predicted catastrophic global famines that never came to pass. They believe that it achieved their goals because "it alerted people to the importance of environmental issues and brought human numbers into the debate on the human future."
π Electrochemical RAM
Electrochemical Random-Access Memory (ECRAM) is a type of non-volatile memory (NVM) with multiple levels per cell (MLC) designed for deep learning analog acceleration. An ECRAM cell is a three-terminal device composed of a conductive channel, an insulating electrolyte, an ionic reservoir, and metal contacts. The resistance of the channel is modulated by ionic exchange at the interface between the channel and the electrolyte upon application of an electric field. The charge-transfer process allows both for state retention in the absence of applied power, and for programming of multiple distinct levels, both differentiating ECRAM operation from that of a field-effect transistor (FET). The write operation is deterministic and can result in symmetrical potentiation and depression, making ECRAM arrays attractive for acting as artificial synaptic weights in physical implementations of artificial neural networks (ANN). The technological challenges include open circuit potential (OCP) and semiconductor foundry compatibility associated with energy materials. Universities, government laboratories, and corporate research teams have contributed to the development of ECRAM for analog computing. Notably, Sandia National Laboratories designed a lithium-based cell inspired by solid-state battery materials, Stanford University built an organic proton-based cell, and International Business Machines (IBM) demonstrated in-memory selector-free parallel programming for a logistic regression task in an array of metal-oxide ECRAM designed for insertion in the back end of line (BEOL). In 2022, researchers at Massachusetts Institute of Technology built an inorganic, CMOS-compatible protonic technology that achieved near-ideal modulation characteristics using nanosecond fast pulses