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🔗 Physics

Landauer's principle is a physical principle pertaining to the lower theoretical limit of energy consumption of computation. It holds that "any logically irreversible manipulation of information, such as the erasure of a bit or the merging of two computation paths, must be accompanied by a corresponding entropy increase in non-information-bearing degrees of freedom of the information-processing apparatus or its environment".

Another way of phrasing Landauer's principle is that if an observer loses information about a physical system, the observer loses the ability to extract work from that system.

A so-called logically-reversible computation, in which no information is erased, may in principle be carried out without releasing any heat. This has led to considerable interest in the study of reversible computing. Indeed, without reversible computing, increases in the number of computations-per-joule-of-energy-dissipated must come to a halt by about 2050: because the limit implied by Landauer's principle will be reached by then, according to Koomey's law.

At 20 °C (room temperature, or 293.15 K), the Landauer limit represents an energy of approximately 0.0175 eV, or 2.805 zJ. Theoretically, room‑temperature computer memory operating at the Landauer limit could be changed at a rate of one billion bits per second (1Gbps) with energy being converted to heat in the memory media at the rate of only 2.805 trillionths of a watt (that is, at a rate of only 2.805 pJ/s). Modern computers use millions of times as much energy per second.

🔗 Video games 🔗 Video games/Nintendo

Link: The Faces of Evil, Zelda: The Wand of Gamelon and Zelda's Adventure are action-adventure games produced by Philips for their CD-i format as part of Nintendo's The Legend of Zelda video game series. Not designed for Nintendo platforms, the games owe their existence to negotiations related to Nintendo's decision not to have Philips create a CD add-on to the Super NES. During these negotiations, Philips secured the rights to use Nintendo characters in CD-i third-party developer games. The Faces of Evil and The Wand of Gamelon were developed by Animation Magic and were both released in North America on October 10, 1993, and Zelda's Adventure was developed by Viridis and was released in North America on June 5, 1994. The games were given little funding or development time, and Nintendo provided only cursory input. None of the games are canonical to the Zelda franchise.

CD-i players did not sell well and the games saw relatively small sales figures. Though the games initially received largely positive reviews, they have been universally criticized since the mid-2000s. This is attributed to the reaction of many gamers to the obscure games' full motion video cutscenes when they first became widely available through video-sharing websites such as YouTube. The cutscenes are perceived to be of poor quality. Because the aging early 1990s visual effects of the titles failed to live up to the graphic effects of the 2000s, and because for many fans this was their first experience of the games, the CD-i Zelda titles have developed a critical reputation as particularly poor based largely on animation quality and to an extent awkward controls. In the eyes of "devout" hardcore gamers, according to Edge, the games are now considered "tantamount to blasphemy".

Faces of Evil and Wand of Gamelon are played using the side-scrolling view introduced in Zelda II: The Adventure of Link, while Zelda's Adventure has a top-down view reminiscent of the original The Legend of Zelda. All the CD-i Zelda games begin with animated FMVs to illustrate the capabilities of the CD-ROM format, save Zelda's Adventure, which begins with a live-action video.

🔗 Germany 🔗 Military history 🔗 Crime 🔗 Politics 🔗 Guild of Copy Editors 🔗 Military history/World War II 🔗 Military history/German military history 🔗 Politics/Fascism 🔗 Military history/European military history

From 1933 to the end of the Second World War, high-ranking officers of the Armed Forces of Nazi Germany accepted vast bribes in the form of cash, estates, and tax exemptions in exchange for their loyalty to Nazism. Unlike bribery at lower ranks in the Wehrmacht, which was also widespread, these payments were regularized, technically legal and made with the full knowledge and consent of the leading Nazi figures.

🔗 Internet 🔗 Telecommunications

Super Dimension Fortress (SDF, also known as freeshell.org) is a non-profit public access UNIX shell provider on the Internet. It has been in continual operation since 1987 as a non-profit social club. The name is derived from the Japanese anime series The Super Dimension Fortress Macross; the original SDF server was a BBS for anime fans. From its BBS roots, which have been well documented as part of the BBS: The Documentary project, SDF has grown into a feature-rich provider serving members around the world.

🔗 Physics 🔗 Physics/relativity

The ladder paradox (or barn-pole paradox) is a thought experiment in special relativity. It involves a ladder, parallel to the ground, travelling horizontally at relativistic speed (near the speed of light) and therefore undergoing a Lorentz length contraction. The ladder is imagined passing through the open front and rear doors of a garage or barn which is shorter than its rest length, so if the ladder was not moving it would not be able to fit inside. To a stationary observer, due to the contraction, the moving ladder is able to fit entirely inside the building as it passes through. On the other hand, from the point of view of an observer moving with the ladder, the ladder will not be contracted, and it is the building which will be Lorentz contracted to an even smaller length. Therefore, the ladder will not be able to fit inside the building as it passes through. This poses an apparent discrepancy between the realities of both observers.

This apparent paradox results from the mistaken assumption of absolute simultaneity. The ladder is said to fit into the garage if both of its ends can be made to be simultaneously inside the garage. The paradox is resolved when it is considered that in relativity, simultaneity is relative to each observer, making the answer to whether the ladder fits inside the garage also relative to each of them.

🔗 Australia 🔗 United States History 🔗 Australia/Australian history 🔗 Australia/South Australia

Rain follows the plow is the conventional name for a now-discredited theory of climatology that was popular throughout the American West and Australia during the late 19th century. The phrase was employed as a summation of the theory by Charles Dana Wilber:

God speed the plow. ... By this wonderful provision, which is only man's mastery over nature, the clouds are dispensing copious rains ... [the plow] is the instrument which separates civilization from savagery; and converts a desert into a farm or garden. ... To be more concise, Rain follows the plow.

The basic premise of the theory was that human habitation and agriculture through homesteading effected a permanent change in the climate of arid and semi-arid regions, making these regions more humid. The theory was widely promoted in the 1870s as a justification for the settlement of the Great Plains, a region previously known as the "Great American Desert". It was also used to justify the expansion of wheat growing on marginal land in South Australia during the same period.

According to the theory, increased human settlement in the region and cultivation of soil would result in an increased rainfall over time, rendering the land more fertile and lush as the population increased. As later historical records of rainfall indicated, the theory was based on faulty evidence arising from brief climatological fluctuations that happened to coincide with settlement, an example of the logical fallacy that correlation means causation. The theory was later refuted by climatologists and is now definitively regarded as pure superstition.

🔗 Computer science

In computer science, the maximum sum subarray problem, also known as the maximum segment sum problem, is the task of finding a contiguous subarray with the largest sum, within a given one-dimensional array A[1...n] of numbers. Formally, the task is to find indices ${\displaystyle i}$ and ${\displaystyle j}$ with ${\displaystyle 1\leq i\leq j\leq n}$, such that the sum

${\displaystyle \sum _{x=i}^{j}A[x]}$

is as large as possible. (Some formulations of the problem also allow the empty subarray to be considered; by convention, the sum of all values of the empty subarray is zero.) Each number in the input array A could be positive, negative, or zero.

For example, for the array of values [−2, 1, −3, 4, −1, 2, 1, −5, 4], the contiguous subarray with the largest sum is [4, −1, 2, 1], with sum 6.

Some properties of this problem are:

1. If the array contains all non-negative numbers, then the problem is trivial; a maximum subarray is the entire array.
2. If the array contains all non-positive numbers, then a solution is any subarray of size 1 containing the maximal value of the array (or the empty subarray, if it is permitted).
3. Several different sub-arrays may have the same maximum sum.

This problem can be solved using several different algorithmic techniques, including brute force, divide and conquer, dynamic programming, and reduction to shortest paths.

🔗 Technology 🔗 Sweden 🔗 Metalworking

Gauge blocks (also known as gage blocks, Johansson gauges, slip gauges, or Jo blocks) are a system for producing precision lengths. The individual gauge block is a metal or ceramic block that has been precision ground and lapped to a specific thickness. Gauge blocks come in sets of blocks with a range of standard lengths. In use, the blocks are stacked to make up a desired length.

An important feature of gauge blocks is that they can be joined together with very little dimensional uncertainty. The blocks are joined by a sliding process called wringing, which causes their ultra-flat surfaces to cling together. A small number of gauge blocks can be used to create accurate lengths within a wide range. By using 3 blocks at a time taken from a set of 30 blocks, one may create any of the 1000 lengths from 3.000 to 3.999 mm in 0.001 mm steps (or .3000 to .3999 inches in 0.0001 inch steps). Gauge blocks were invented in 1896 by Swedish machinist Carl Edvard Johansson. They are used as a reference for the calibration of measuring equipment used in machine shops, such as micrometers, sine bars, calipers, and dial indicators (when used in an inspection role). Gauge blocks are the main means of length standardization used by industry.

A unidirectional network (also referred to as a unidirectional gateway or data diode) is a network appliance or device that allows data to travel in only one direction. Data diodes can be found most commonly in high security environments, such as defense, where they serve as connections between two or more networks of differing security classifications. Given the rise of industrial IoT and digitization, this technology can now be found at the industrial control level for such facilities as nuclear power plants, power generation and safety critical systems like railway networks.

After years of development the use of data diodes have increased creating two variations:

• Data diode: Network appliance or device allowing raw data to travel only in one direction, used in guaranteeing information security or protection of critical digital systems, such as industrial control systems, from inbound cyber attacks.

• Unidirectional gateway: Combination of hardware and software running in proxy computers in the source and destination networks. The hardware, a data diode, enforces physical unidirectionality and the software replicates databases and emulates protocol servers to handle bi-directional communication. The unidirectional gateway is capable of transferring multiple protocols and data types simultaneously. It contains a broader range of cybersecurity features like, secure boot, certificate management, data integrity, forward error correction (FEC), secure communication via TLS, among others. A unique characteristic is that data is transferred deterministically (to predetermined locations) with a protocol "break" that allows the data to be transferred through the data diode.

Data diodes are commonly found in high security military and government environments, and are now becoming widely spread in sectors like oil & gas, water/wastewater, airplanes (between flight control units and in-flight entertainment systems), manufacturing and cloud connectivity for industrial IoT. New regulations have increased demand and with increased capacity, major technology vendors have lowered the cost of the core technology.