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Mikhail Ostrogradsky

Mikhail Vasilyevich Ostrogradsky (Михаи́л Васи́льевич Острогра́дский; 24 September 1801 – 1 January 1862), also known as Mykhailo Vasyliovych Ostrohradskyi (Миха́йло Васи́льович Острогра́дський), was a Ukrainian mathematician, mechanician, and physicist of Ukrainian Cossack ancestry. Ostrogradsky was a student of Timofei Osipovsky and is considered to be a disciple of Leonhard Euler, who was known as one of the leading mathematicians of Imperial Russia.

Life
Ostrogradsky was born on 24 September 1801 in the village of Pashennaya (at the time in the Poltava Governorate, Russian Empire, today in Kremenchuk Raion, Poltava Oblast, Ukraine). From 1816 to 1820, he studied under Timofei Osipovsky (1765–1832) and graduated from the Imperial University of Kharkov. When Osipovsky was suspended on religious grounds in 1820, Ostrogradsky refused to be examined and he never received his Ph.D. degree. From 1822 to 1826, he studied at the Sorbonne and at the Collège de France in Paris, France. In 1828, he returned to the Russian Empire and settled in Saint Petersburg, where he was elected a member of the Academy of Sciences. He also became a professor of the main military engineering school of the Russian Empire.

Ostrogradsky died in Poltava in 1862, aged 60. The Kremenchuk Mykhailo Ostrohradskyi National University in Kremenchuk, Poltava oblast, as well as Ostrogradsky street in Poltava, are named after him.

Work

He worked mainly in the mathematical fields of calculus of variations, integration of algebraic functions, number theory, algebra, geometry, probability theory and in the fields of applied mathematics, mathematical physics and classical mechanics. In the latter, his key contributions are in the motion of an elastic body and the development of methods for integration of the equations of dynamics and fluid power, following up on the works of Euler, Joseph Louis Lagrange, Siméon Denis Poisson and Augustin Louis Cauchy.

In Russia, his work in these fields was continued by Nikolay Dmitrievich Brashman (1796–1866), August Yulevich Davidov (1823–1885) and especially by Nikolai Yegorovich Zhukovsky (1847–1921).

Ostrogradsky did not appreciate the work on non-Euclidean geometry of Nikolai Lobachevsky from 1823, and he rejected it, when it was submitted for publication in the Saint Petersburg Academy of Sciences.

Ostrogradsky was a teacher of the children of Emperor Nicholas I.

Divergence theorem
In 1826, Ostrogradsky gave the first general proof of the divergence theorem, which was discovered by Lagrange in 1762. This theorem may be expressed using Ostrogradsky's equation:
 * $$ \iiint_V \left( {\partial P\over \partial x} + {\partial Q\over \partial y} + {\partial R\over \partial z} \right) dx \, dy \, dz =

\iint_\Sigma \left( P \cos \lambda + Q \cos \mu + R \cos \nu \right) d\Sigma $$; where P, Q, and R are differentiable functions of x, y, and z defined on the compact region V bounded by a smooth closed surface Σ; λ, μ, and ν are the angles that the outward normal to Σ makes with the positive x, y, and z axes respectively; and dΣ is the surface area element on Σ.

Ostrogradsky's integration method
His method for integrating rational functions is well known. First, we separate the rational part of the integral of a fractional rational function, the sum of the rational part (algebraic fraction) and the transcendental part (with the logarithm and the arctangent). Second, we determine the rational part without integrating it, and we assign a given integral in Ostrogradsky's form:

 * $$ \int {R(x)\over P(x)} \, dx = {T(x)\over S(x)} + \int {X(x)\over Y(x)} \, dx, $$

where $$P(x),\, S(x),\, Y(x)$$ are known polynomials of degrees p, s, y respectively; $$R(x)$$ is a known polynomial of degree not greater than $$p - 1$$; and $$T(x),\, X(x)$$ are unknown polynomials of degrees not greater than $$s - 1$$ and $$y - 1$$ respectively.

Third, $$S(x)$$ is the greatest common divisor of $$P(x)$$ and $$P'(x)$$. Fourth, the denominator of the remaining integral $$Y(x)$$ can be calculated from the equation $$P(x) = S(x)\,Y(x)$$.

When we differentiate both sides of the equation above, we get: $$ R(x) = T'(x)Y(x) - T(x)H(x) + X(x)S(x) $$,

where $$H(x) = {Y(x) S'(x) \over S(x)}$$.

It can be shown that $$H(x)$$ is polynomial.

title: Mikhail Ostrogradsky


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Talk:Aviation

"Hangkong" listed at Redirects for discussion
The redirect [//en.wikipedia.org/w/index.php?title=Hangkong&redirect=no Hangkong] has been listed at redirects for discussion to determine whether its use and function meets the redirect guidelines. Readers of this page are welcome to comment on this redirect at  until a consensus is reached. Mia Mahey (talk) 04:51, 1 June 2024 (UTC)

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Talk:Aviation


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British Museum Reading Room

The British Museum Reading Room, situated in the centre of the Great Court of the British Museum, used to be the main reading room of the British Library. In 1997, this function moved to the new British Library building at St Pancras, London, but the Reading Room remains in its original form at the British Museum.

Designed by Sydney Smirke and opened in 1857, the Reading Room was in continual use until its temporary closure for renovation in 1997. It was reopened in 2000, and from 2007 to 2017 it was used to stage temporary exhibitions. The reading room was closed to the public again in 2013 and converted for use as the museum's archive. It was reopened for guided tours in 2023, and reopened as a study space in July 2024.

Construction and design
In the early 1850s the museum library was in need of a larger reading room and the then-Keeper of Printed Books, Antonio Panizzi, following an earlier competition idea by William Hosking, came up with the thought of a round room in the central courtyard. The building was designed by Sydney Smirke and was constructed between 1854 and 1857. The building used cast iron, concrete, glass and the latest technology in ventilation and heating. The dome, inspired by the Pantheon in Rome, has a diameter of 42.6 metres but is not technically free standing: constructed in segments on cast iron, the ceiling is suspended and made out of papier-mâché. Book stacks built around the reading room were made of iron to take the huge weight and add fire protection. There were forty kilometres of shelving in the stacks prior to the library's relocation to the new site.

British Museum Library
The Reading Room was officially opened on 2 May 1857 with a 'breakfast' (that included champagne and ice cream) laid out on the catalogue desks. A public viewing was held between 8 and 16 May, attracting over 62,000 visitors. Tickets to it included a plan of the library.

Regular users had to apply in writing and be issued a reader's ticket by the Principal Librarian. During the period of the British Library, access was restricted to registered researchers only; however, reader's credentials were generally available to anyone who could show that they were a serious researcher. The Reading Room was used by a large number of famous figures, including notably Sun Yat-sen, Karl Marx, Oscar Wilde, Friedrich Hayek, Marcus Garvey, Bram Stoker, Mahatma Gandhi, Rudyard Kipling, George Orwell, George Bernard Shaw, Mark Twain, Vladimir Lenin (using the name Jacob Richter ), Virginia Woolf, Arthur Rimbaud, Muhammad Ali Jinnah, H. G. Wells, and Arthur Conan Doyle.

In 1973, the British Library Act 1972 detached the library department from the British Museum, but it continued to host the now separated British Library in the same Reading Room and building as the museum until 1997.

Restoration
In 1997 the British Library moved to its own specially constructed building next to St Pancras railway station and all the books and shelving were removed. As part of the redevelopment of the Great Court, the Reading Room was fully renovated and restored, including the papier-mâché ceiling which was repaired to its original colour scheme, having previously undergone radical redecorations (the initial design of the roof was considered excessive at the time).

The Reading Room was reopened in 2000, allowing all visitors, not just library ticket-holders, to enter it. It held a collection of 25,000 books focusing on the cultures represented in the museum along with an information centre and the Walter and Leonore Annenberg Centre.

Exhibition space
In 2007 the books and facilities installed in 2000 were removed, and the Reading Room was relaunched as a venue for special exhibitions, beginning with one featuring China's Terracotta Army. The general library for visitors, Paul Hamlyn Library, was moved to a room accessible through nearby Room 2, but closed permanently on 13 August 2011. This is an earlier library that has also had distinguished users, including Thomas Babington Macaulay, William Makepeace Thackeray, Robert Browning, Giuseppe Mazzini, Charles Darwin, and Charles Dickens.

A selection of past exhibitions:

Closure and reopening
In 2013, the Reading Room was again closed to the public, this time indefinitely. With its role as an exhibition space superseded by the newer purpose-built World Conservation and Exhibitions Centre, the Reading Room was converted for use as the museum's archive. It was briefly reopened in 2018, but for a series of concerts and not for its original purpose. For the rest of the 2010s and early 2020s, the Reading Room remained closed to the public, and museum officials were in discussions on what to do with the space.

In 2023, the Reading Room reopened to the public for guided tours. The tours, which are free, last approximately 20 minutes and must be booked in advance. Only one tour is conducted each week, at a specific time on a specific day; during the first wave of tours in March and April 2023, tours only ran on Tuesdays at 11:30 am. Visitors are monitored during the tour and are not permitted to borrow books or take photographs in the Reading Room.

References in art and popular culture
The British Museum Reading Room is the subject of an eponymous poem, "The British Museum Reading Room", by Louis MacNeice. Much of the action of David Lodge's 1965 novel The British Museum Is Falling Down takes place in the old Reading Room. The 'Glass Ceiling' of Anabel Donald's 1994 novel is the ceiling of the Reading Room, where the denouement is set.

Alfred Hitchcock used the Reading Room and the dome of the British Museum as a location for the climax of his first sound film Blackmail (1929). Other movies with key scenes in the Reading Room include Night of the Demon (1957) and in the 2001 Japanese anime OVA Read or Die, the Room is used as a secret entrance to the British Library's fictional "Special Operations Division".

In Sir Max Beerbohm's short story, Enoch Soames, first published in May 1916, an obscure writer makes a deal with the Devil to visit the Reading Room one hundred years in the future, in order to know what posterity thinks about him and his work.

The British Museum and the Reading Room serve as the settings for An Encounter at the Museum, an anthology of romance novellas by Claudia Dain and Deb Marlowe, among others.

Virginia Woolf made reference to the British Museum Reading Room in a passage from her 1929 essay, A Room of One's Own. She wrote, "The swing doors swung open, and there one stood under the vast dome as if one were a thought in the huge bald forehead which is so splendidly encircled by a band of famous names."

Richard Henry Dana Jr. visited the Reading Room on 10 September 1860 with his London friend Henry T. Parker, and reported that "Parker calls & takes me to the British Museum, to see the Reading Room, wh. has been built since 1856 [Dana's prior visit]. It is the room where students & readers have their desks, & consult the textbooks, cyclopedias, catalogs &c., & from wh. they send orders for books to the Library – the Library not being visited, at all, for study. There is no such room as this in Europe. It is a circle, with a dome, lighted from above, & its diameter is 4 feet greater than that of the dome of St. Paul's. The autographs are now open to the view of all, spread out in glass cases, – as well as much other lit. curiosities. This is the grandest Literary & Scientific institution (not for instruction) in the world. The Reading Room, I told Parker, was a temple to the deification of Bibliology."

The writer Bernard Falk (1882–1960) quotes the British historian Thomas Carlyle (1795–1881) as having declared that the Reading Room of the British Museum was a convenient asylum for imbeciles whose friends wished them out of mischief's way.

title: British Museum Reading Room


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Talk:Air transport

What is the difference between "Aviation" and "Air transport"? Does anybody else think that these two fledgling articles should be merged? GrahamN 00:15 Jan 31, 2003 (UTC)

title: Talk:Air transport


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Talk:Consciousness Explained

If I remember correctly, Dennett does not use the expression "eliminativist materialism" -- rather, the term was invented as a snarl word by his critics. If this is the case, a better expression could be found for use in this article. --FOo

 * Hello. It was me who put in the term "eliminativist materialism", not realising that it was considered non-NPOV. This chap I know who has recently finished doing an M.A. in Philosophy of Mind uses the term quite a bit, and although he doesn't consider Dennett's treatment of consciousness to be very persuasive, he uses the term in what sounds to me quite a neutral way. I'll ask him about it again. (By the way, I'm trying to get him to write some articles on philosophy here, but so far without success!) -- Oliver P. 02:23 Jan 31, 2003 (UTC)

He argues from the standpoint of eliminativist materialism, which has resulted in other philosophers accusing him of defining away the problem. I removed this -- eliminative materialism is a term which other philosophers invented to describe their own positions, and which does not apply to Dennett. There are numerous other factual inaccuracies in this article -- maybe I'll correct them soon enough. -- Adam Conover.

Brains in Jars
There is a very (imho) unpersuasive argument in the book that we can't possibly be "brains in jars" because its too complex to fool us with a computer program Dennet could imagine. Erm. Maybe this should be covered (as it is quite at odds with the rest of the book), and I'd be very interested in any responses to it...

 * To me it sounds as though you've only read the first chapter of the book. ;) In all seriousness, though, I think you're misunderstanding Dennett's argument. On the other hand, he probably didn't feel the need to refute solipsism, as that's been adequately done by other philosophers time and time again.   —  Adam Conover † 17:07, Dec 6, 2004 (UTC)

 * Where can I find some of these adequate refutations? - Gyan 30 June 2005 18:36 (UTC)`

One good place is Fabric of Reality by David Deutsch

 * You mean its been inadequately dodged by other philosophers time and time again.

Parallelism vs. Serialism
This reminds me very much of Julian Jaynes and The Origin of Consciousness in the Breakdown of the Bicameral Mind. I'm sure there's also similar support from people studying lingusitics and semiotics; especially with regard to Sapir-Whorf Hypothesis. First comes the information -- the thinking; then comes your internal modelling of that information -- language / self-consciousness. -- zuzu

Julian Jaynes
I was actually coming here to see if Julian Jaynes would get a mention, as Dennett is somewhat of an admirer and Julian Jaynes work acted as somewhat of a muse for Dennet's later ideas regarding consciousness. Philosophyfellow (talk) 14:56, 4 November 2013 (UTC)

Qualia and Zombies
I have added a paragraph dealing with one of the more important topics of the book, ie qualia. 1Z 12:32, 24 December 2006 (UTC)1Z

Peter Wilberg
Two external links have been added which appear to be 1) to personal web pages 2) belonging to someone who is not a recognised authority 3) not dealing specifically with the book "consciousness explained" but rather qualia in general.

I will delete if there are no objections.1Z 15:28, 12 January 2007 (UTC)

Fair use rationale for Image:Consciousness Explained.jpg
Image:Consciousness Explained.jpg is being used on this article. I notice the image page specifies that the image is being used under fair use but there is no explanation or rationale as to why its use in Wikipedia articles constitutes fair use. In addition to the boilerplate fair use template, you must also write out on the image description page a specific explanation or rationale for why using this image in each article is consistent with fair use.

Please go to the image description page and edit it to include a fair use rationale. Using one of the templates at Fair use rationale guideline is an easy way to insure that your image is in compliance with Wikipedia policy, but remember that you must complete the template. Do not simply insert a blank template on an image page.

If there is other other fair use media, consider checking that you have specified the fair use rationale on the other images used on this page. Note that any fair use images uploaded after 4 May, 2006, and lacking such an explanation will be deleted one week after they have been uploaded, as described on criteria for speedy deletion. If you have any questions please ask them at the Media copyright questions page. Thank you.BetacommandBot 21:46, 2 June 2007 (UTC)

 * Issue has been resolved.--Nodrokov (talk) 15:12, 10 May 2021 (UTC)

Supporting statement
A supporting statement for the "multiple drafts" theory is that there is no single point in the brain where all information funnels in. There is not one place in the brain through which all the causal trains must pass, in order to deposit their content in consciousness. This is worded to sound like WP:OR. However, if it can be related to the book or to something a reviewer has said, ti cna go back in. (Preferably somewhere nearer to the discussion of MD).1Z 14:27, 24 August 2007 (UTC)

Fair use rationale for Image:Consciousness Explained.jpg
Image:Consciousness Explained.jpg is being used on this article. I notice the image page specifies that the image is being used under fair use but there is no explanation or rationale as to why its use in this Wikipedia article constitutes fair use. In addition to the boilerplate fair use template, you must also write out on the image description page a specific explanation or rationale for why using this image in each article is consistent with fair use.

Please go to the image description page and edit it to include a fair use rationale. Using one of the templates at Fair use rationale guideline is an easy way to insure that your image is in compliance with Wikipedia policy, but remember that you must complete the template. Do not simply insert a blank template on an image page.

If there is other fair use media, consider checking that you have specified the fair use rationale on the other images used on this page. Note that any fair use images lacking such an explanation can be deleted one week after being tagged, as described on criteria for speedy deletion. If you have any questions please ask them at the Media copyright questions page. Thank you.

BetacommandBot (talk) 04:56, 2 January 2008 (UTC)

 * Issue has been resolved.--Nodrokov (talk) 15:11, 10 May 2021 (UTC)

Odd paragraph
Under the Inverted Spectrum section, there is a poorly-worded, non-punctual paragraph that tries to delve into specifics which have already been addressed more generally in the body of the article.

"it is of course possible but unprovable that this in fact exists. if what one person sees as the color red, another sees as what the first knows as green, but the second person calls that color red, who will ever know the difference unless they experience what the other does, which is impossible. imagine waking up as another person and seeing red grass and red trees for instance."

I'm not a Wikipedia person, and it will be some time before I take the time to learn all the rules and rationale for edits, so I just wanted to raise the issue and hope that someone else will delete it or fix it somehow.

168.150.253.55 (talk) 01:15, 24 February 2008 (UTC)

Autoreference and the objectivity of subjectivity
This book seems autoreferential to me, in the sense that it can be summed up by the following: "If consciousness is this, then consciousness is this"

Secondly, about the unscientificallity of subjectivity, it must be noted that all science eventually comes from the "subjective" contents of consciousness. All our thinking is happening inside that "subjective" consciousness. It is all that we are eventually aware of. We are never aware of anything else than those "subjective" contents".

And there is a problem with this concept of subjectivity itself. It is unadapted because ambiguous. It designates both the dillemma between measurable and not measurable, and the difference between conscious and non-conscious in its essence. But the fact that consciousness is not measurable, is not its main property - its "conscious property" is. Therefore, because of this merely semantic ambiguity, the "subjective" consciousness can be objective in the sense that its "subjective" (ie. conscious) contents can be "objective" if they represent measured data. If I am conscious tha an object is 1.8 meters long, this "subjective (conscious) content is "in the same time "objective".

This is where the author errs. He happilly mixes the two meanings.

Interestingly, in quantum physics too, a number of things are not measurable... — Preceding unsigned comment added by 161.53.149.242 (talk) 13:08, 28 July 2011 (UTC) Great criticism, I'm agree with you. — Preceding unsigned comment added by 87.221.128.89 (talk) 13:48, 31 January 2012 (UTC)

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Citation re. Nagel
Can we get a citation for this passage?

Critics of Dennett's approach, such as David Chalmers and Thomas Nagel, argue that Dennett's argument misses the point of the inquiry by merely redefining consciousness as an external property and ignoring the subjective aspect completely.

5.148.145.68 (talk) 13:18, 3 October 2017 (UTC)

Reception is mostly criticisms
I don't think a book that was heralded as as "the book of the year," or whatever, warrants a reception section that is 90% just people taking issues with the philosophy itself. To the best of my knowledge, the book is considered well-written and a good representation of the philosophy it espouses, regardless of the merits of that philosophy. That is more what "reception" is about.

I do acknowledge that the philosophical objections are relevant, but should either be balanced or possibly moved to a separate section.

I say this as someone who dislikes Dennett's philosophy and is always glad to see it torn down. 2603:7081:1603:A300:88DD:6591:E7E:9FF (talk) 18:36, 23 April 2024 (UTC)

title: Talk:Consciousness Explained


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Computational geometry

Computational geometry is a branch of computer science devoted to the study of algorithms which can be stated in terms of geometry. Some purely geometrical problems arise out of the study of computational geometric algorithms, and such problems are also considered to be part of computational geometry. While modern computational geometry is a recent development, it is one of the oldest fields of computing with a history stretching back to antiquity.

Computational complexity is central to computational geometry, with great practical significance if algorithms are used on very large datasets containing tens or hundreds of millions of points. For such sets, the difference between O(n2) and O(n log n) may be the difference between days and seconds of computation.

The main impetus for the development of computational geometry as a discipline was progress in computer graphics and computer-aided design and manufacturing (CAD/CAM), but many problems in computational geometry are classical in nature, and may come from mathematical visualization.

Other important applications of computational geometry include robotics (motion planning and visibility problems), geographic information systems (GIS) (geometrical location and search, route planning), integrated circuit design (IC geometry design and verification), computer-aided engineering (CAE) (mesh generation), and computer vision (3D reconstruction).

The main branches of computational geometry are:

 * Combinatorial computational geometry, also called algorithmic geometry, which deals with geometric objects as discrete entities. A groundlaying book in the subject by Preparata and Shamos dates the first use of the term "computational geometry" in this sense by 1975.
 * Numerical computational geometry, also called machine geometry, computer-aided geometric design (CAGD), or geometric modeling, which deals primarily with representing real-world objects in forms suitable for computer computations in CAD/CAM systems. This branch may be seen as a further development of descriptive geometry and is often considered a branch of computer graphics or CAD. The term "computational geometry" in this meaning has been in use since 1971.

Although most algorithms of computational geometry have been developed (and are being developed) for electronic computers, some algorithms were developed for unconventional computers (e.g. optical computers )

Combinatorial computational geometry
The primary goal of research in combinatorial computational geometry is to develop efficient algorithms and data structures for solving problems stated in terms of basic geometrical objects: points, line segments, polygons, polyhedra, etc.

Some of these problems seem so simple that they were not regarded as problems at all until the advent of computers. Consider, for example, the Closest pair problem:

 * Given n points in the plane, find the two with the smallest distance from each other.

One could compute the distances between all the pairs of points, of which there are n(n-1)/2, then pick the pair with the smallest distance. This brute-force algorithm takes O(n2) time; i.e. its execution time is proportional to the square of the number of points. A classic result in computational geometry was the formulation of an algorithm that takes O(n log n). Randomized algorithms that take O(n) expected time, as well as a deterministic algorithm that takes O(n log log n) time, have also been discovered.

Problem classes
The core problems in computational geometry may be classified in different ways, according to various criteria. The following general classes may be distinguished.

Static problem
In the problems of this category, some input is given and the corresponding output needs to be constructed or found. Some fundamental problems of this type are:

 * Convex hull: Given a set of points, find the smallest convex polyhedron/polygon containing all the points.
 * Line segment intersection: Find the intersections between a given set of line segments.
 * Delaunay triangulation
 * Voronoi diagram: Given a set of points, partition the space according to which points are closest to the given points.
 * Linear programming
 * Closest pair of points: Given a set of points, find the two with the smallest distance from each other.
 * Farthest pair of points
 * Largest empty circle: Given a set of points, find a largest circle with its center inside of their convex hull and enclosing none of them.
 * Euclidean shortest path: Connect two points in a Euclidean space (with polyhedral obstacles) by a shortest path.
 * Polygon triangulation: Given a polygon, partition its interior into triangles
 * Mesh generation
 * Boolean operations on polygons

The computational complexity for this class of problems is estimated by the time and space (computer memory) required to solve a given problem instance.

Geometric query problems
In geometric query problems, commonly known as geometric search problems, the input consists of two parts: the search space part and the query part, which varies over the problem instances. The search space typically needs to be preprocessed, in a way that multiple queries can be answered efficiently.

Some fundamental geometric query problems are:

 * Range searching: Preprocess a set of points, in order to efficiently count the number of points inside a query region.
 * Point location problem: Given a partitioning of the space into cells, produce a data structure that efficiently tells in which cell a query point is located.
 * Nearest neighbor: Preprocess a set of points, in order to efficiently find which point is closest to a query point.
 * Ray tracing: Given a set of objects in space, produce a data structure that efficiently tells which object a query ray intersects first.

If the search space is fixed, the computational complexity for this class of problems is usually estimated by:
 * the time and space required to construct the data structure to be searched in
 * the time (and sometimes an extra space) to answer queries.

For the case when the search space is allowed to vary, see "Dynamic problems".

Dynamic problems
Yet another major class is the dynamic problems, in which the goal is to find an efficient algorithm for finding a solution repeatedly after each incremental modification of the input data (addition or deletion input geometric elements). Algorithms for problems of this type typically involve dynamic data structures. Any of the computational geometric problems may be converted into a dynamic one, at the cost of increased processing time. For example, the range searching problem may be converted into the dynamic range searching problem by providing for addition and/or deletion of the points. The dynamic convex hull problem is to keep track of the convex hull, e.g., for the dynamically changing set of points, i.e., while the input points are inserted or deleted.

The computational complexity for this class of problems is estimated by:
 * the time and space required to construct the data structure to be searched in
 * the time and space to modify the searched data structure after an incremental change in the search space
 * the time (and sometimes an extra space) to answer a query.

Variations
Some problems may be treated as belonging to either of the categories, depending on the context. For example, consider the following problem.
 * Point in polygon: Decide whether a point is inside or outside a given polygon.

In many applications this problem is treated as a single-shot one, i.e., belonging to the first class. For example, in many applications of computer graphics a common problem is to find which area on the screen is clicked by a pointer. However, in some applications, the polygon in question is invariant, while the point represents a query. For example, the input polygon may represent a border of a country and a point is a position of an aircraft, and the problem is to determine whether the aircraft violated the border. Finally, in the previously mentioned example of computer graphics, in CAD applications the changing input data are often stored in dynamic data structures, which may be exploited to speed-up the point-in-polygon queries.

In some contexts of query problems there are reasonable expectations on the sequence of the queries, which may be exploited either for efficient data structures or for tighter computational complexity estimates. For example, in some cases it is important to know the worst case for the total time for the whole sequence of N queries, rather than for a single query. See also "amortized analysis".

Numerical computational geometry
This branch is also known as geometric modelling and computer-aided geometric design (CAGD).

Core problems are curve and surface modelling and representation.

The most important instruments here are parametric curves and parametric surfaces, such as Bézier curves, spline curves and surfaces. An important non-parametric approach is the level-set method.

Application areas of computational geometry include shipbuilding, aircraft, and automotive industries.

Combinatorial/algorithmic computational geometry
Below is the list of the major journals that have been publishing research in geometric algorithms. Please notice with the appearance of journals specifically dedicated to computational geometry, the share of geometric publications in general-purpose computer science and computer graphics journals decreased.
 * ACM Computing Surveys
 * ACM Transactions on Graphics
 * Acta Informatica
 * Advances in Geometry
 * Algorithmica
 * Ars Combinatoria
 * Computational Geometry: Theory and Applications
 * Communications of the ACM
 * Computer Aided Geometric Design
 * Computer Graphics and Applications
 * Computer Graphics World
 * Computing in Geometry and Topology
 * Discrete & Computational Geometry
 * Geombinatorics
 * Geometriae Dedicata
 * IEEE Transactions on Graphics
 * IEEE Transactions on Computers
 * IEEE Transactions on Pattern Analysis and Machine Intelligence
 * Information Processing Letters
 * International Journal of Computational Geometry and Applications
 * Journal of Combinatorial Theory, Series B
 * Journal of Computational Geometry
 * Journal of Differential Geometry
 * Journal of the ACM
 * Journal of Algorithms
 * Journal of Computer and System Sciences
 * Management Science
 * Pattern Recognition
 * Pattern Recognition Letters
 * SIAM Journal on Computing
 * SIGACT News; featured the "Computational Geometry Column" by Joseph O'Rourke
 * Theoretical Computer Science
 * The Visual Computer

title: Computational geometry


text:
Filipino

Filipino may refer to:

 * Something from or related to the Philippines
 * Filipino language, a de facto standardized variety of Tagalog, the national language, and one of the two official languages of the Philippines
 * Filipinos, people who are natives, citizens and/or nationals of the Philippines, natural-born or naturalized
 * Filipinos (snack food), a brand cookies manufactured in Europe

title: Filipino


text:
Talk:Computational geometry

Comment
This is my version of a long stub. Someone else should fill in the details, I'm not a specialist. Loisel 00:38 Jan 31, 2003 (UTC)

Useful and useless links
Just a short comment on the link "Geomtry in action": 99% of the links on the "Geomtry in action" - Site are dead. I know, a link like "Geometry in action" sounds good, but it's useless if none of the links on a site dedicated to collecting links works. I suggest deleting the "Geomtry in action" - Link. — Preceding unsigned comment added by 194.138.39.59 (talk) 12:19, 27 April 2012 (UTC)

Books added
hello- I just added four references for books on the topic. two points to note.
 * One, I'm not sure that the last book by O'Rourke belongs there, as it's the only non general book on the topic, still, I found it very useful to my understanding of computational geometry
 * Two, Maybe we could list title's ISBNs and compress authorship a bit somehow? I'm not sure about citation conventions, if someone wants to fix it up, that would be great

If someone disagrees, and feels such information doesn't have a place here ( it goes go out of date quickly) -- by all means, pull it out, but it's handy to point readers to more external sources of information, IMHO.

---
 * Also -- more external website links would be useful, if anyone is so inclined.
 * O'Rourke's book is a good general reference if you remove all the code; it should stay, IMO.

 * I put the references in a more academic style and wikified them. See Cite_sources for a reference on these BibTeX-style citations.  In my opinion, one shouldn't go to great lengths to keep a citation short -- I see thorough citation as an essential part of any academic community, although exceptions must be made.  I say that having cited cell biology papers with > 50 authors.  groan!

Adking80 22:03, 14 May 2005 (UTC)
 * Godfried Toussaint's webpage has some decent-to-good Java tutorials on various problems that he has students do for projects. I won't put a link to it because (a) I don't know how much interest there would be and (b) he was my prof, so there's a bit of bias, but if someone else thinks it should be linked, by all means put it up!

Merge proposal

 * Oppose. to merge List of books in computational geometry here. It is not a simple bibliography. It is a list with annotations. We have quite a few separate lists of books. It makes sense to merge articles accidentally started by several people on the same topic or to merge some unimportant issues that do not really warrant a separate article. Keeping the dicussed pages separately does not hinder understanding of the main topic in any way: the list is just one click away. The supporters of merging may look at it in this way: the "list of books" page is a merge of several separate small articles for individual books. I hope it will make you feel better. `'mikka 01:19, 13 January 2007 (UTC)

Split proposal
Mikkalai, thanks for changing the 3 branches to only 2. And I have no intention to start "moving other topics elsewhere" without a lot of discussion. That's why I placed the proposal in the article, and started this discussion here. Now, we only have 2 b Therefore, I agree that this article should not be split, but I believe that the division using the two terms that occur only in Wikipedia is not adequate. It leads the reader to believe that the separation into these two branches is widely accepted, but in fact it is only the way by which the wikipedia article is organized. I think that a broad description of computational geometry, followed by several examples, with some explanation of the different "flavors" they have, is better. Let's see if more people give feedback and we can decide what to do about it. Gfonsecabr 21:02, 8 April 2007 (UTC)ranches (unless someone oposes and recreates the 3rd one): Combinatorial Computational Geometry and Numerical Computational Geometry. I agree with you that "Numeri Are there any references that divide computational geometry into the 3 areas listed in this article? Essentially all the modern use I see of computational geometry refers to what is described as combinatorial computational geometry. Therefore, I believe this page should talk only about what is described as combinatorial computational geometry. The other topics can be moved to other pages (as stubs, since there is very little information anyway). Gfonsecabr 02:06, 8 April 2007 (UTC)

 * First of all, if you are asking this question, then probably you are not in a position to have an educated opinon.
 * Now as to answers: Yes there are references that distinguish different uses of the term "computational geometry", starting from the seminal book by Preparata and Shamos. What is more, there are books in these different topics under the same name. Third, before starting moving "other topics elsewhere, you must write more than one sentence. Finaly, fourth, "numerical geometry" is not an established discipline to write such article. The term does exist and seen in google, but this is mostly not what the current article about.  `'mikka 18:52, 8 April 2007 (UTC)cal Geometry" is not an established discipline. I believe you changed it to "Numerical Computational Geometry" which is not established with this name either: if you google either "numerical computational geometry" or "combinatorial computational geometry" you will only find this wikipedia article (and copies of it)!

I believe that most of what is considered computational geometry nowadays fits in the Combinatorial Computational Geometry branch. Nevertheless, I also agree with Goodman and O'Rourke preface to Handbook of Discrete and Computational Geometry, which says: "...'computational geometry,' which referred not long ago to simply the design and analysis of geometric algorithms, has in recent years broadened its scope, and now means the study of geometric problems from a computational point of view, including also computational convexity, computational topology, and questions involving the combinatorial complexity of arrangements and polyhedra"

Problems with definition of computational geometry
The proposed in the article definition of computational geometry as study of algorithms to solve problems stated in the terms of geometry raises questions. The so definined computational geometry obviously includes algorithms of geometric constructions since they are also algorithms to solve problems also stated in the terms of geometry. However, the article does not mention such algoithms.

Thus, either the article has to be augmented by mentioning such algorithms or the definition has to be modified. —Preceding unsigned comment added by 47.248.0.45 (talk • contribs)

 * If it needs to be adjusted you can re-write it so that it is correct and then cite your source. - Barkeep  19:04, 30 May 2007 (UTC)
 * You missed the beginning of the sentence: "In computer science..." AFAIK Compass and straightedge constructions are mostly of historical and theoretical interest. Just as computations with abacus are not part of computer science, geometric construction with your right hand tied to your back is not studied within computational geometry, simply because of lack modern applications that warrant wasting money on such research. For comparison, geometric problems arising in robot motion are a reputable area of research, including solving 3D assembly puzzles, which I'd say in a way akin to ruler and compass construction puzzles. This topic (I mean geometric assembly amd motion planning problems) is also underdeveloped in wikipedia. `'юзырь mikka 21:22, 30 May 2007 (UTC)

 * You're wrong. Computer Science is actually the study of all computation, both abstract and mechanical, you can't exclude neither abacus computations nor straightedge constructions.--201.21.181.131 (talk) 01:43, 1 August 2011 (UTC)

Why does the article not cite the source of the current definition ? Where is it from ? Who is the author ? —Preceding unsigned comment added by 47.248.0.45 (talk • contribs)
 * See "References" section. BTW the preparata-shamos book does mention ruler and compass as prehistory of computational geometry.
 * Please sign your posts, e.g., by typing 4 tildas ( ~ ), which will automatically convert into a sig similar to mine: `'юзырь mikka 21:22, 30 May 2007 (UTC)

The definition should be irrespective of whether it is in computer science, or on Earth, or on the Moon or elsewhere. Also the definition should be irrespective of whether it is possible to get money for such research or not. What you say amounts to the following: Computational geometry is a study of such algorithms to solve problems stated in the terms of geometry, which can be performed by contemporary digital computers AND for which one can get financial support. Right ?

But then we have the following problem: none of algorithms of computational geometry can be performed by contemporary digital computers. All these algorithms assume absolute precision of computation. As soon as the finite precision is taken into account, all the algorithms fall apart. They do not guarantee obtaining the desired results or even their approximations.

Thus, the definition should be further specified as follows: computational geometry is a study of such algorithms to solve problems stated in the terms of geometry, which can be performed by non-existing idealistic digital computer with infinite precision of computation AND for which one can get money. Right ?

47.248.0.45 13:35, 31 May 2007 (UTC)
 * First of all, please don't put your words in my mouth. I explained a possible reasoning under the current definition and about scope of the article, not gave you a yet another definition.
 * Now, about your comments. Please be advised that definitions of a very large number of terms do depend on "whether it is in computer science, or on Earth, or on the Moon". You may start from "bug" article. In your case you have some reason, I admit, because I am not aware of significant usage of the term "computational geometry" beyund comp sci. At the same time I fail to see the problem here. The definition merely specifies the domain where the term is used: computer science. At the same time, having a particular context makes it unnecessary t write longer explanations.
 * Finally, the definition in wikipedia is not cast in stone. User:Barkeep have already told you, if you find a better definition please bring it in, without much angry talk. If you don't like the definition of computational geometry, I would very much like to see you criticizing of wikipedia's definitions of mathematics or philosophy. The point is, some things simply cannot be defined in a narrow way. In particular, I see no reason why "ruler and compass" cannot be studied by computer science. `'юзырь:mikka 17:50, 31 May 2007 (UTC)

My point was to show that computational geometry has to study any geometric algorithms regardless of what computers they are intended for - be it "ruler & compass" or "contemporary digital computers" or something else. The reason is that NONE of them are developed for real digital computers but for their unrealistic idealizations which are not better than analog computers or ruler & compass. Why then restrict oneself to one bad model and not to investigate others ? When running on real digital computers the outcome of the algorithms of "computational geometry" may be worse than when analog computers are applied to solving the same geometric problems or even worse than when ruler & compass are employed. For example, convex hull can be constructed with the help of ruler only. And this construction always suceeds unlike algorithms of "computational geometry". The same hold for constructing shortest path, etc.

And such studies into applying other computers to solving geometric problems do exist. But your encyclopedia misses them, whereas it has to reflect all reasonable points of view and not to restrict itself to presenting the views of the dominating school of thoughts.

47.248.0.45 14:11, 1 June 2007 (UTC)
 * Wiipedia does not "restrict itself" to anything. It is simply that wikipedia is not perfect. It contains what is writen by you and me and John Doe. You are welcome to add more topic. If you cannot write yourself, you may also calmly, without much agitation suggest titles of new articles. It is not area of political debate or interethnic conflicts, and no one is going to fight you here. `'юзырь:mikka 15:12, 1 June 2007 (UTC)

I would suggest you (as the author of the bulk of the article) to add a section on the computational models for geometric algorithms, emphasize that the most of the research was done for a specific model, outline its shortcomings, mention other models proposed and algorithms for them, refer to comparison of the algorithms for different models from the standpoint of the divergency of computation, etc.

Then it will be worth of an encyclopedia and not a compilation from pieces by O'Rourke & Co.

47.248.0.45 16:40, 1 June 2007 (UTC)
 * I am afraid that you don't understand the nature of Wikipedia. By its core rule Attribution it is a compilation. It is a major difference from classical encycopedias written by renowned experts all by themselves. By no means I am a world famous expert. It just so happens that there is very few CompGeom experts who are willing to waste their time in a project that brings them neither money nor glory. So take it easy on us; we have no "legal obligations" before readership beyond our free will. And BTW, what you see does not consist of pieces from O'Rourke only. (Not that it is a bad book either.) While I do have this book, I didn't take a single piece from it (some others did, I agree).
 * That said, thank you for your suggestions. I (or someone else) will try to do something in some spare time. As you understand, I cannot do it right now, happily clicking the keyboard. Serious texts require serious thought. `'юзырь:mikka 17:38, 1 June 2007 (UTC)

List of problems
In the list of computational geometry problems, should we add What about the problem of calculating the area of a union of N rectangles? It seems to me a very basic geometric problem. Does it have a page in Wikipedia? --Erel Segal (talk) 16:42, 15 December 2010 (UTC)
 * Sweep line algorithm?
 * Dynamic programming?

Kinetic triangulation
There is a whole series of new articles awaiting new article review, with computer science talk page templates. See Category:All unreviewed new articles. For example, Kinetic triangulation.

I would appreciate reviews by an editor who knows this subject and can provide talk page templates with class and importance. The tags should be removed, and of course any tags for problems should be added. --DThomsen8 (talk) 13:09, 9 June 2012 (UTC)

title: Talk:Computational geometry


text:
Internet Archive

The Internet Archive is an American nonprofit digital library founded in 1996 by Brewster Kahle. It provides free access to collections of digitized materials including websites, software applications, music, audiovisual, and print materials. The Archive also advocates for a free and open Internet. , the Internet Archive held more than 44 million print materials, 10.6 million videos, 1 million software programs, 15 million audio files, 4.8 million images, 255,000 concerts, and over 835 billion web pages in its Wayback Machine. Its mission is committing to provide "universal access to all knowledge".

The Internet Archive allows the public to upload and download digital material to its data cluster, but the bulk of its data is collected automatically by its web crawlers, which work to preserve as much of the public web as possible. Its web archive, the Wayback Machine, contains hundreds of billions of web captures. The Archive also oversees numerous book digitization projects, collectively one of the world's largest book digitization efforts.

History

Brewster Kahle founded the Archive in May 1996, around the same time that he began the for-profit web crawling company Alexa Internet. The earliest known archived page on the site was saved on May 10, 1996, at 2:42 pm UTC (7:42 am PDT). By October of that year, the Internet Archive had begun to archive and preserve the World Wide Web in large amounts. The archived content became more easily available to the general public in 2001, through the Wayback Machine.

In late 1999, the Archive expanded its collections beyond the web archive, beginning with the Prelinger Archives. Now, the Internet Archive includes texts, audio, moving images, and software. It hosts a number of other projects: the NASA Images Archive, the contract crawling service Archive-It, and the wiki-editable library catalog and book information site Open Library. Soon after that, the Archive began working to provide specialized services relating to the information access needs of the print-disabled; publicly accessible books were made available in a protected Digital Accessible Information System (DAISY) format.

According to its website:

"Most societies place importance on preserving artifacts of their culture and heritage. Without such artifacts, civilization has no memory and no mechanism to learn from its successes and failures. Our culture now produces more and more artifacts in digital form. The Archive's mission is to help preserve those artifacts and create an Internet library for researchers, historians, and scholars."

In August 2012, the Archive announced that it has added BitTorrent to its file download options for more than 1.3 million existing files, and all newly uploaded files. This method is the fastest means of downloading media from the Archive, as files are served from two Archive data centers, in addition to other torrent clients which have downloaded and continue to serve the files. On November 6, 2013, the Internet Archive's headquarters in San Francisco's Richmond District caught fire, destroying equipment and damaging some nearby apartments. According to the Archive, it lost a side-building housing one of 30 of its scanning centers; cameras, lights, and scanning equipment worth hundreds of thousands of dollars; and "maybe 20 boxes of books and film, some irreplaceable, most already digitized, and some replaceable". The nonprofit Archive sought donations to cover the estimated $600,000 in damage.

An overhaul of the site was launched as beta in November 2014, and the legacy layout was removed in March 2016.

In November 2016, Kahle announced that the Internet Archive was building the Internet Archive of Canada, a copy of the Archive to be based somewhere in Canada. The announcement received widespread coverage due to the implication that the decision to build a backup archive in a foreign country was because of the upcoming presidency of Donald Trump. Kahle was quoted as saying:

"On November 9th in America, we woke up to a new administration promising radical change. It was a firm reminder that institutions like ours, built for the long-term, need to design for change. For us, it means keeping our cultural materials safe, private and perpetually accessible. It means preparing for a Web that may face greater restrictions. It means serving patrons in a world in which government surveillance is not going away; indeed it looks like it will increase. Throughout history, libraries have fought against terrible violations of privacy—where people have been rounded up simply for what they read. At the Internet Archive, we are fighting to protect our readers' privacy in the digital world."

Beginning in 2017, OCLC and the Internet Archive have collaborated to make the Archive's records of digitized books available in WorldCat.

Since 2018, the Internet Archive visual arts residency, which is organized by Amir Saber Esfahani and Andrew McClintock, helps connect artists with the Archive's over 48 petabytes of digitized materials. Over the course of the yearlong residency, visual artists create a body of work which culminates in an exhibition. The hope is to connect digital history with the arts and create something for future generations to appreciate online or off. Previous artists in residence include Taravat Talepasand, Whitney Lynn, and Jenny Odell.

The Internet Archive acquires most materials from donations, such as hundreds of thousands of 78 rpm discs from Boston Public Library in 2017, a donation of 250,000 books from Trent University in 2018, and the entire collection of Marygrove College's library in 2020 after it closed. All material is then digitized and retained in digital storage, while a digital copy is returned to the original holder and the Internet Archive's copy, if not in the public domain, is lent to patrons worldwide one at a time under the controlled digital lending (CDL) theory of the first-sale doctrine.

During the week of May 27, 2024, The Internet Archive suffered a series of distributed denial of service (DDoS) attacks that made its services unavailable intermittently, sometimes for hours at a time, over a period of several days.

Operations
The Archive is a 501(c)(3) nonprofit operating in the United States. In 2019, it had an annual budget of $36 million, derived from revenue from its Web crawling services, various partnerships, grants, donations, and the Kahle-Austin Foundation. The Internet Archive also manages periodic funding campaigns. For instance, a December 2019 campaign had a goal of reaching $6 million in donations. The Archive is headquartered in San Francisco, California. From 1996 to 2009, its headquarters were in the Presidio of San Francisco, a former U.S. military base. Since 2009, its headquarters have been at 300 Funston Avenue in San Francisco, a former Christian Science Church. At one time, most of its staff worked in its book-scanning centers; as of 2019, scanning is performed by 100 paid operators worldwide. The Archive also has data centers in three Californian cities: San Francisco, Redwood City, and Richmond. To reduce the risk of data loss, the Archive creates copies of parts of its collection at more distant locations, including the Bibliotheca Alexandrina in Egypt and a facility in Amsterdam.

The Archive is a member of the International Internet Preservation Consortium and was officially designated as a library by the state of California in 2007.

Wayback Machine

The Internet Archive capitalized on the popular use of the term "WABAC Machine" from a segment of The Adventures of Rocky and Bullwinkle cartoon (specifically, Peabody's Improbable History), and uses the name "Wayback Machine" for its service that allows archives of the World Wide Web to be searched and accessed. This service allows users to view some of the archived web pages. The Wayback Machine was created as a joint effort between Alexa Internet (owned by Amazon.com) and the Internet Archive when a three-dimensional index was built to allow for the browsing of archived web content. Hundreds of billions of web sites and their associated data (images, source code, documents, etc.) are saved in a database. The service can be used to see what previous versions of web sites used to look like, to grab original source code from web sites that may no longer be directly available, or to visit web sites that no longer even exist. Not all web sites are available because many web site owners choose to exclude their sites. As with all sites based on data from web crawlers, the Internet Archive misses large areas of the web for a variety of other reasons. A 2004 paper found international biases in the coverage, but deemed them "not intentional". In 2017, the Wayback Machine director announced that its crawlers would ignore robots.txt instructions and archive pages even if website owners asked bots not to access them.

A "Save Page Now" archiving feature was made available in October 2013, accessible on the lower right of the Wayback Machine's main page. Once a target URL is entered and saved, the web page will become part of the Wayback Machine. Through the Internet address web.archive.org, users can upload to the Wayback Machine a large variety of contents, including PDF and data compression file formats. The Wayback Machine creates a permanent local URL of the upload content, that is accessible in the web, even if not listed while searching in the https://archive.org official website.

In October 2016, it was announced that the way web pages are counted would be changed, resulting in the decrease of the archived pages counts shown. Embedded objects such as pictures, videos, style sheets, JavaScripts are no longer counted as a "web page", whereas HTML, PDF, and plain text documents remain counted.

In September 2020, the Internet Archive announced a partnership with Cloudflare – an American content delivery network service provider – to automatically index websites served via its "Always Online" services.

Archive-It

Created in early 2006, Archive-It is a web archiving subscription service that allows institutions and individuals to build and preserve collections of digital content and create digital archives. Archive-It allows the user to customize their capture or exclusion of web content they want to preserve for cultural heritage reasons. Through a web application, Archive-It partners can harvest, catalog, manage, browse, search, and view their archived collections.

In terms of accessibility, the archived web sites are full text searchable within seven days of capture. Content collected through Archive-It is captured and stored as a WARC file. A primary and back-up copy is stored at the Internet Archive data centers. A copy of the WARC file can be given to subscribing partner institutions for geo-redundant preservation and storage purposes to their best practice standards. Periodically, the data captured through Archive-It is indexed into the Internet Archive's general archive.

, Archive-It had more than 275 partner institutions in 46 U.S. states and 16 countries that have captured more than 7.4 billion URLs for more than 2,444 public collections. Archive-It partners are universities and college libraries, state archives, federal institutions, museums, law libraries, and cultural organizations, including the Electronic Literature Organization, North Carolina State Archives and Library, Stanford University, Columbia University, American University in Cairo, Georgetown Law Library, and many others.

Internet Archive Scholar
In September 2020 Internet Archive announced a new initiative to archive and preserve open access academic journals, called Internet Archive Scholar. Its full-text search index includes over 25 million research articles and other scholarly documents preserved in the Internet Archive. The collection spans from digitized copies of eighteenth century journals through the latest open access conference proceedings and pre-prints crawled from the World Wide Web.

General Index
In 2021, the Internet Archive announced the initial version of the General Index, a publicly available index to a collection of 107 million academic journal articles.

Text collection

The scanning performed by the Internet Archive is financially supported by libraries and foundations. , when there were approximately 1 million texts, the entire collection was greater than 0.5 petabytes, which included raw camera images, cropped and skewed images, PDFs, and raw OCR data.

, the Internet Archive was operating 33 scanning centers in five countries, digitizing about 1,000 books a day for a total of more than 2 million books, in a total collection of 4.4 million books – including material digitized by others and fed into the Internet Archive; at that time, users were performing more than 15 million downloads per month.

The material digitized by others includes more than 300,000 books that were contributed to the collection, between about 2006 and 2008, by Microsoft through its Live Search Books project, which also included financial support and scanning equipment directly donated to the Internet Archive. On May 23, 2008, Microsoft announced it would be ending its Live Book Search project and would no longer be scanning books, donating its remaining scanning equipment to its former partners.

Around October 2007, Archive users began uploading public domain books from Google Book Search. , there were more than 900,000 Google-digitized books in the Archive's collection; the books are identical to the copies found on Google, except without the Google watermarks, and are available for unrestricted use and download. Brewster Kahle revealed in 2013 that this archival effort was coordinated by Aaron Swartz, who, with a "bunch of friends", downloaded the public domain books from Google slowly enough and from enough computers to stay within Google's restrictions. They did this to ensure public access to the public domain. The Archive ensured the items were attributed and linked back to Google, which never complained, while libraries "grumbled". According to Kahle, this is an example of Swartz's "genius" to work on what could give the most to the public good for millions of people.

In addition to books, the Archive offers free and anonymous public access to more than four million court opinions, legal briefs, or exhibits uploaded from the United States Federal Courts' PACER electronic document system via the RECAP web browser plugin. These documents had been kept behind a federal court paywall. On the Archive, they had been accessed by more than six million people by 2013.

The Archive's BookReader web app, built into its website, has features such as single-page, two-page, and thumbnail modes; fullscreen mode; page zooming of high-resolution images; and flip page animation.

Open Library
The Open Library is another project of the Internet Archive. The project seeks to include a web page for every book ever published: it holds 25 million catalog records of editions. It also seeks to be a web-accessible public library: it contains the full texts of approximately 1,600,000 public domain books (out of the more than five million from the main texts collection), as well as in-print and in-copyright books, many of which are fully readable, downloadable and full-text searchable; it offers a two-week loan of e-books in its controlled digital lending program for over 647,784 books not in the public domain, in partnership with over 1,000 library partners from six countries after a free registration on the web site. Open Library is a free and open-source software project, with its source code freely available on GitHub.

The Open Library faces objections from some authors and the Society of Authors, who hold that the project is distributing books without authorization and is thus in violation of copyright laws, and four major publishers initiated a copyright infringement lawsuit against the Internet Archive in June 2020 to stop the Open Library project.

Digitizing sponsors for books
Many large institutional sponsors have helped the Internet Archive provide millions of scanned publications (text items). Some sponsors that have digitized large quantities of texts include the University of Toronto's Robarts Library, the University of Alberta Libraries, the University of Ottawa, the Library of Congress, Boston Library Consortium member libraries, the Boston Public Library, the Princeton Theological Seminary Library, and many others.

In 2017, the MIT Press authorized the Internet Archive to digitize and lend books from the press's backlist, with financial support from the Arcadia Fund. A year later, the Internet Archive received further funding from the Arcadia Fund to invite some other university presses to partner with the Internet Archive to digitize books, a project called "Unlocking University Press Books".

The Library of Congress created numerous Handle System identifiers that pointed to free digitized books in the Internet Archive. The Internet Archive and Open Library are listed on the Library of Congress website as a source of e-books.

Media collections

In addition to web archives, the Internet Archive maintains extensive collections of digital media that are attested by the uploader to be in the public domain in the United States or licensed under a license that allows redistribution, such as Creative Commons licenses. Media are organized into collections by media type (moving images, audio, text, etc.), and into sub-collections by various criteria. Each of the main collections includes a "Community" sub-collection (formerly named "Open Source") where general contributions by the public are stored.

Audio Archive
The Audio Archive is an audio archive that includes music, audiobooks, news broadcasts, old time radio shows, podcasts, and a wide variety of other audio files. , there are more than 15,000,000 free digital recordings in the collection. The subcollections include audio books and poetry, podcasts, non-English audio, and many others. The sound collections are curated by B. George, director of the ARChive of Contemporary Music.

Next to the stock HTML5 audio player, Winamp-resembling Webamp is available.

Digital Library of Amateur Radio and Communications
A project to preserve recordings of amateur radio transmissions, with funding from the Amateur Radio Digital Communications foundation.

Live Music Archive
The Live Music Archive sub-collection includes more than 170,000 concert recordings from independent musicians, as well as more established artists and musical ensembles with permissive rules about recording their concerts, such as the Grateful Dead, and more recently, The Smashing Pumpkins. Also, Jordan Zevon has allowed the Internet Archive to host a definitive collection of his father Warren Zevon's concert recordings. The Zevon collection ranges from 1976 to 2001 and contains 126 concerts including 1,137 songs.

The Great 78 Project
The Great 78 Project aims to digitize 250,000 78 rpm singles (500,000 songs) from the period between 1880 and 1960, donated by various collectors and institutions. It has been developed in collaboration with the Archive of Contemporary Music and George Blood Audio, responsible for the audio digitization.

Netlabels
The Archive has a collection of freely distributable music that is streamed and available for download via its Netlabels service. The music in this collection generally has Creative Commons-license catalogs of virtual record labels.

Images collection
This collection contains more than 3.5 million items. Cover Art Archive, Metropolitan Museum of Art – Gallery Images, NASA Images, Occupy Wall Street Flickr Archive, and USGS Maps are some sub-collections of Image collection.

Cover Art Archive
The Cover Art Archive is a joint project between the Internet Archive and MusicBrainz, whose goal is to make cover art images on the Internet. this collection contains more than 1,400,000 items.

Metropolitan Museum of Art images
The images of this collection are from the Metropolitan Museum of Art. This collection contains more than 140,000 items.

NASA Images
The NASA Images archive was created through a Space Act Agreement between the Internet Archive and NASA to bring public access to NASA's image, video, and audio collections in a single, searchable resource. The IA NASA Images team worked closely with all of the NASA centers to keep adding to the ever-growing collection. The nasaimages.org site launched in July 2008 and had more than 100,000 items online at the end of its hosting in 2012.

Occupy Wall Street Flickr archive
This collection contains Creative Commons-licensed photographs from Flickr related to the Occupy Wall Street movement. This collection contains more than 15,000 items.

USGS Maps
This collection contains more than 59,000 items from Libre Map Project.

Machinima Archive
One of the sub-collections of the Internet Archive's Video Archive is the Machinima Archive. This small section hosts many Machinima videos. Machinima is a digital artform in which computer games, game engines, or software engines are used in a sandbox-like mode to create motion pictures, recreate plays, or even publish presentations or keynotes. The archive collects a range of Machinima films from internet publishers such as Rooster Teeth and Machinima.com as well as independent producers. The sub-collection is a collaborative effort among the Internet Archive, the How They Got Game research project at Stanford University, the Academy of Machinima Arts and Sciences, and Machinima.com.

Microfilm collection
This collection contains approximately 160,000 microfilmed items from a variety of libraries including the University of Chicago Libraries, the University of Illinois at Urbana-Champaign, the University of Alberta, Allen County Public Library, and the National Technical Information Service.

Moving image collection
The Internet Archive holds a collection of approximately 3,863 feature films. Additionally, the Internet Archive's Moving Image collection includes: newsreels, classic cartoons, pro- and anti-war propaganda, The Video Cellar Collection, Skip Elsheimer's "A.V. Geeks" collection, early television, and ephemeral material from Prelinger Archives, such as advertising, educational, and industrial films, as well as amateur and home movie collections.

Subcategories of this collection include:
 * IA's Brick Films collection, which contains stop-motion animation filmed with Lego bricks, some of which are "remakes" of feature films.
 * IA's Election 2004 collection, a non-partisan public resource for sharing video materials related to the 2004 United States presidential election.
 * IA's FedFlix collection, Joint Venture NTIS-1832 between the National Technical Information Service and Public.Resource.Org that features "the best movies of the United States Government, from training films to history, from our national parks to the U.S. Fire Academy and the Postal Inspectors"
 * IA's Independent News collection, which includes sub-collections such as the Internet Archive's World At War competition from 2001, in which contestants created short films demonstrating "why access to history matters". Among their most-downloaded video files are eyewitness recordings of the devastating 2004 Indian Ocean earthquake.
 * IA's September 11 Television Archive, which contains archival footage from the world's major television networks of the terrorist attacks of September 11, 2001, as they unfolded on live television.

Open Educational Resources
Open Educational Resources is a digital collection at archive.org. This collection contains hundreds of free courses, video lectures, and supplemental materials from universities in the United States and China. The contributors of this collection are ArsDigita University, Hewlett Foundation, MIT, Monterey Institute, and Naropa University.

TV News Search & Borrow
In September 2012, the Internet Archive launched the TV News Search & Borrow service for searching U.S. national news programs. The service is built on closed captioning transcripts and allows users to search and stream 30-second video clips. Upon launch, the service contained "350,000 news programs collected over 3 years from national U.S. networks and stations in San Francisco and Washington D.C." According to Kahle, the service was inspired by the Vanderbilt Television News Archive, a similar library of televised network news programs. In contrast to Vanderbilt, which limits access to streaming video to individuals associated with subscribing colleges and universities, the TV News Search & Borrow allows open access to its streaming video clips. In 2013, the Archive received an additional donation of "approximately 40,000 well-organized tapes" from the estate of a Philadelphia woman, Marion Stokes. Stokes "had recorded more than 35 years of TV news in Philadelphia and Boston with her VHS and Betamax machines."

Miscellaneous collections
Brooklyn Museum collection contains approximately 3,000 items from Brooklyn Museum. In December 2020, the film research library of Lillian Michelson was donated to the archive.

Physical media

Voicing a strong reaction to the idea of books simply being thrown away, and inspired by the Svalbard Global Seed Vault, Kahle now envisions collecting one copy of every book ever published. "We're not going to get there, but that's our goal", he said. Alongside the books, Kahle plans to store the Internet Archive's old servers, which were replaced in 2010.

Software
The Internet Archive has "the largest collection of historical software online in the world", spanning 50 years of computer history in terabytes of computer magazines and journals, books, shareware discs, FTP sites, video games, etc. The Internet Archive has created an archive of what it describes as "vintage software", as a way to preserve them. The project advocated for an exemption from the United States Digital Millennium Copyright Act to permit them to bypass copy protection, which the United States Copyright Office approved in 2003 for a period of three years. The Archive does not offer the software for download, as the exemption is solely "for the purpose of preservation or archival reproduction of published digital works by a library or archive." The Library of Congress renewed the exemption in 2006, and in 2009 indefinitely extended it pending further rulemakings. The Library reiterated the exemption as a "Final Rule" with no expiration date in 2010. In 2013, the Internet Archive began to provide select video games browser-playable via MESS, for instance the Atari 2600 game E.T. the Extra-Terrestrial. Since December 23, 2014, the Internet Archive presents, via a browser-based DOSBox emulation, thousands of DOS/PC games   for "scholarship and research purposes only". In November 2020, the Archive introduced a new emulator for Adobe Flash called Ruffle, and began archiving Flash animations and games ahead of the December 31, 2020, end-of-life for the Flash plugin across all computer systems.

Table Top Scribe System
A combined hardware software system has been developed that performs a safe method of digitizing content.

Credit Union
From 2012 to November 2015, the Internet Archive operated the Internet Archive Federal Credit Union, a federal credit union based in New Brunswick, New Jersey, with the goal of providing access to low- and middle-income people. Throughout its short existence, the IAFCU experienced significant conflicts with the National Credit Union Administration, which severely limited the IAFCU's loan portfolio and concerns over serving Bitcoin firms. At the time of its dissolution, it consisted of 395 members and was worth $2.5 million.

Decentralization
Since 2019, the Internet Archive organizes an event called Decentralized Web Camp (DWeb Camp). It is an annual camp that brings together a diverse global community of contributors in a natural setting. The camp aims to tackle real-world challenges facing the web and co-create decentralized technologies for a better internet. It aims to foster collaboration, learning, and fun while promoting principles of trust, human agency, mutual respect, and ecological awareness.

Wayforward Machine
On 30 September 2021, as a part of its 25th anniversary celebration, Internet Archive launched the "Wayforward Machine", a satirical, fictional website covered with pop-ups asking for personal information. The site was intended to depict a fictional dystopian timeline of real-world events leading to such a future, such as the repeal of Section 230 of the United States Code in 2022 and the introduction of advertising implants in 2041.

Ceramic archivists collection

The Great Room of the Internet Archive features a collection of more than 100 ceramic figures representing employees of the Internet Archive, with the 100th statue immortalizing Aaron Swartz. This collection, inspired by the statues of the Xian warriors in China, was commissioned by Brewster Kahle, sculpted by Nuala Creed, and as of 2014, is ongoing.

Artists in residence
The Internet Archive visual arts residency, organized by Amir Saber Esfahani, is designed to connect emerging and mid-career artists with the Archive's millions of collections and to show what is possible when open access to information intersects with the arts. During this one-year residency, selected artists develop a body of work that responds to and utilizes the Archive's collections in their own practice.

 * 2019 Residency Artists: Caleb Duarte, Whitney Lynn, and Jeffrey Alan Scudder
 * 2018 Residency Artists: Mieke Marple, Chris Sollars, and Taravat Talepasand
 * 2017 Residency Artists: Laura Kim, Jeremiah Jenkins, and Jenny Odell

Opposition to National security letters, bills and settlements
On May 8, 2008, it was revealed that the Internet Archive had successfully challenged an FBI national security letter asking for logs on an undisclosed user.

On November 28, 2016, it was revealed that a second FBI national security letter had been successfully challenged that had been asking for logs on another undisclosed user.

The Internet Archive blacked out its web site for 12 hours on January 18, 2012, in protest of the Stop Online Piracy Act and the PROTECT IP Act bills, two pieces of legislation in the United States Congress that they argued would "negatively affect the ecosystem of web publishing that led to the emergence of the Internet Archive". This occurred in conjunction with the English Wikipedia blackout, as well as numerous other protests across the Internet.

The Internet Archive is a member of the Open Book Alliance, which has been among the most outspoken critics of the Google Book Settlement. The Archive advocates an alternative digital library project.

Hosting of disputed media
On October 9, 2016, the Internet Archive was temporarily blocked in Turkey after it was used (amongst other file hosting services) by hackers to host 17 GB of leaked government emails.

Because the Internet Archive only lightly moderates uploads, it includes resources that may be valued by extremists and the site may be used by them to evade block listing. In February 2018, the Counter Extremism Project said that the Archive hosted terrorist videos, including the beheading of Alan Henning, and had declined to respond to requests about the videos. In May 2018, a report published by the cyber-security firm Flashpoint stated that the Islamic State was using the Internet Archive to share its propaganda. Chris Butler, from the Internet Archive, responded that they regularly spoke to the US and EU governments about sharing information on terrorism. In April 2019, Europol, acting on a referral from French police, asked the Internet Archive to remove 550 sites of "terrorist propaganda". The Archive rejected the request, saying that the reports were wrong about the content they pointed to, or were too broad for the organization to comply with. On July 14, 2021, the Internet Archive held a joint "Referral Action Day" with Europol to target terrorist videos.

A 2021 article said that jihadists regularly used the Internet Archive for "dead drops" of terrorist videos. In January 2022, a former UCLA lecturer's 800-page manifesto, containing racist ideas and threats against UCLA staff, was uploaded to the Internet Archive. The manifesto was removed by the Internet Archive after a week, amidst discussion about whether such documents should be preserved by archivists or not. Another 2022 paper found "an alarming volume of terrorist, extremist, and racist material on the Internet Archive". A 2023 paper reported that Neo-Nazis collect links to online, publicly available resources to be shared with new recruits. As the Internet Archive hosts uploaded texts that are not allowed on other websites, Nazi and neo-Nazi books in the Archive (e.g., The Turner Diaries) frequently appear on these lists. These lists also feature older, public domain material created when white supremacist views were more mainstream.

National Emergency Library
In the midst of the COVID-19 pandemic which closed many schools, universities, and libraries, the Archive announced on March 24, 2020, that it was creating the National Emergency Library by removing the lending restrictions it had in place for 1.4 million digitized books in its Open Library but otherwise limiting users to the number of books they could check out and enforcing their return; normally, the site would only allow one digital lending for each physical copy of the book they had, by use of an encrypted file that would become unusable after the lending period was completed. This Library would remain as such until at least June 30, 2020, or until the US national emergency was over, whichever came later. At launch, the Internet Archive allowed authors and rightholders to submit opt-out requests for their works to be omitted from the National Emergency Library.

The Internet Archive said the National Emergency Library addressed an "unprecedented global and immediate need for access to reading and research material" due to the closures of physical libraries worldwide. They justified the move in a number of ways. Legally, they said they were promoting access to those inaccessible resources, which they claimed was an exercise in fair use principles. The Archive continued implementing their controlled digital lending policy that predated the National Emergency Library, meaning they still encrypted the lent copies and it was no easier for users to create new copies of the books than before. An ultimate determination of whether or not the National Emergency Library constituted fair use could only be made by a court. Morally, they also pointed out that the Internet Archive was a registered library like any other, that they either paid for the books themselves or received them as donations, and that lending through libraries predated copyright restrictions.

The Archive had already been criticized by authors and publishers for its prior lending approach, and upon announcement of the National Emergency Library, authors, publishers, and groups representing both took further issue with The Archive and its Open Library project, equating the move to copyright infringement and digital piracy, and using the COVID-19 pandemic as a reason to push the boundaries of copyright. After the works of some of these authors were ridiculed in responses, the Internet Archive's Jason Scott requested that supporters of the National Emergency Library not denigrate anyone's books: "I realize there's strong debate and disagreement here, but books are life-giving and life-changing and these writers made them."

Copyright issues
In November 2005, free downloads of Grateful Dead concerts were removed from the site, following what seemed to be disagreements between some of the former band members. John Perry Barlow identified Bob Weir, Mickey Hart, and Bill Kreutzmann as the instigators of the change, according to an article in The New York Times. Phil Lesh, a founding member of the band, commented on the change in a November 30, 2005, posting to his personal web site:

"It was brought to my attention that all of the Grateful Dead shows were taken down from Archive.org right before Thanksgiving. I was not part of this decision making process and was not notified that the shows were to be pulled. I do feel that the music is the Grateful Dead's legacy and I hope that one way or another all of it is available for those who want it."

A November 30 forum post from Brewster Kahle summarized what appeared to be the compromise reached among the band members. Audience recordings could be downloaded or streamed, but soundboard recordings were to be available for streaming only. Concerts have since been re-added.

In February 2016, Internet Archive users had begun archiving digital copies of Nintendo Power, Nintendo's official magazine for their games and products, which ran from 1988 to 2012. The first 140 issues had been collected, before Nintendo had the archive removed on August 8, 2016. In response to the take-down, Nintendo told gaming website Polygon, "[Nintendo] must protect our own characters, trademarks and other content. The unapproved use of Nintendo's intellectual property can weaken our ability to protect and preserve it, or to possibly use it for new projects".

In August 2017, the Department of Telecommunications of the Government of India blocked the Internet Archive along with other file-sharing websites, in accordance with two court orders issued by the Madras High Court, citing piracy concerns after copies of two Bollywood films were allegedly shared via the service. The HTTP version of the Archive was blocked but it remained accessible using the HTTPS protocol.

In 2023, the Internet Archive became a popular site for Indians to watch the first episode of India: The Modi Question, a BBC documentary. The video was reported to have been removed by the Archive on January 23. The Internet Archive then stated, on January 27, that they had removed the video in response to a BBC request under the Digital Millennium Copyright Act.

The Great 78 Project had been started on the Internet Archive to store digitized versions of pre-1972 songs and albums from 78 rpm phonograph records, for the stated purpose of "the preservation, research and discovery of 78rpm records". The project had started in 2016, at which time the copyright on pre-1972 recordings only had limited duration; in 2019, the U.S. Congress passed the Music Modernization Act which extended pre-1972 recording copyrights to 2067. In August 2023, Sony Music Entertainment and five other major music publishers sued the Internet Archive over the Great 78 Project, asserting the project was engaged in copyright infringement, denying the claim about research purposes since all the music was available via their respective digital and streaming music services. The companies were seeking the statutory damages for nearly 2500 songs named in the suit, for a total of $347 million. The Internet Archive has argued that the crackles and pops in the recordings mean that it is within the doctrine of "fair use" to digitize them for preservation. The plaintiffs said in response, "if ever there were a theory of fair use invented for litigation, this is it".

Publishers' lawsuit
The operation of the National Emergency Library was part of a lawsuit filed against the Internet Archive by four major book publishers—Hachette, HarperCollins, John Wiley & Sons, and Penguin Random House—in June 2020, challenging the copyright validity of the controlled digital lending program. In response, the Internet Archive closed the National Emergency Library on June 16, 2020, rather than the planned June 30, 2020, due to the lawsuit. The plaintiffs, supported by the Copyright Alliance, claimed in their lawsuit that the Internet Archive's actions constituted a "willful mass copyright infringement". In August 2020 the lawsuit trial was tentatively scheduled to begin in November 2021. By June 2022, both parties to the case requested summary judgment for the case, each favoring their respective sides, which Judge John G. Koeltl approved of a summary judgment hearing to take place later in 2022. No summary judgment was issued, and instead a first hearing was held on March 20, 2023. Over the course of the hearing, Judge John G. Koeltl appeared unmoved by the IA's fair use claims and unconvinced that the publishers' market for library e-books was not impacted by their practice.

Senator Thom Tillis of North Carolina, chairman of the intellectual property subcommittee on the Senate Judiciary Committee, said in a letter to the Internet Archive that he was "concerned that the Internet Archive thinks that it—not Congress—gets to determine the scope of copyright law".

As part of its response to the publishers' lawsuit, in late 2020 the Archive launched a campaign called Empowering Libraries (hashtag #EmpoweringLibraries) that portrayed the lawsuit as a threat to all libraries.

In a 2021 preprint article, Argyri Panezi argued that the case "presents two important, but separate questions related to the electronic access to library works; first, it raises questions around the legal practice of digital lending, and second, it asks whether emergency use of copyrighted material might be fair use" and argued that libraries have a public service role to enable "future generations to keep having equal access—or opportunities to access—a plurality of original sources".

In December 2020, Publishers Weekly included the lawsuit among its "Top 10 Library Stories of 2020".

Judge Koeltl ruled on March 24, 2023, against Internet Archive in the case, saying the National Emergency Library concept was not fair use, so the Archive infringed their copyrights by lending out the books without the waitlist restriction. An agreement was then reached for the Internet Archive to pay an undisclosed amount to the publishers. The Internet Archive said afterwards it would appeal this ruling, but otherwise would continue other digital book services which have been previously cleared under case law, such as books for reading-impaired users. An updated report of the appeal process involving the Internet Archive was published on December 18, 2023, by TorrentFreak News. While the Archive has appealed the ruling, it has also removed more than 500,000 books from these publishers to comply with the ruling.

Similar projects

 * archive.today
 * Internet Memory Foundation
 * LibriVox
 * National Digital Information Infrastructure and Preservation Program (NDIIPP)
 * National Digital Library Program (NDLP)
 * Project Gutenberg
 * UK Government Web Archive at The National Archives (United Kingdom)
 * UK Web Archive
 * WebCite

Other

 * Anna's Archive
 * Archive Team
 * Digital dark age
 * Digital preservation
 * Heritrix
 * Library Genesis
 * Link rot
 * List of web archives
 * Memory hole
 * PetaBox
 * Search engine cache

title: Internet Archive