The PGP Word List ("Pretty Good Privacy word list", also called a biometric word list for reasons explained below) is a list of words for conveying data bytes in a clear unambiguous way via a voice channel. They are analogous in purpose to the NATO phonetic alphabet, except that a longer list of words is used, each word corresponding to one of the 256 distinct numeric byte values. == History and structure == The PGP Word List was designed in 1995 by Patrick Juola, a computational linguist, and Philip Zimmermann, creator of PGP. The words were carefully chosen for their phonetic distinctiveness, using genetic algorithms to select lists of words that had optimum separations in phoneme space. The candidate word lists were randomly drawn from Grady Ward's Moby Pronunciator list as raw material for the search, successively refined by the genetic algorithms. The automated search converged to an optimized solution in about 40 hours on a DEC Alpha, a particularly fast machine in that era. The Zimmermann–Juola list was originally designed to be used in PGPfone, a secure VoIP application, to allow the two parties to verbally compare a short authentication string to detect a man-in-the-middle attack (MiTM). It was called a biometric word list because the authentication depended on the two human users recognizing each other's distinct voices as they read and compared the words over the voice channel, binding the identity of the speaker with the words, which helped protect against the MiTM attack. The list can be used in many other situations where a biometric binding of identity is not needed, so calling it a biometric word list may be imprecise. Later, it was used in PGP to compare and verify PGP public key fingerprints over a voice channel. This is known in PGP applications as the "biometric" representation. When it was applied to PGP, the list of words was further refined, with contributions by Jon Callas. More recently, it has been used in Zfone and the ZRTP protocol, the successor to PGPfone. The list is actually composed of two lists, each containing 256 phonetically distinct words, in which each word represents a different byte value between 0 and 255. Two lists are used because reading aloud long random sequences of human words usually risks three kinds of errors: 1) transposition of two consecutive words, 2) duplicate words, or 3) omitted words. To detect all three kinds of errors, the two lists are used alternately for the even-offset bytes and the odd-offset bytes in the byte sequence. Each byte value is actually represented by two different words, depending on whether that byte appears at an odd or an even offset from the beginning of the byte sequence. The two lists are readily distinguished by the number of syllables; the odd list has words of three syllables, the even list has two. The two lists have a maximum word length of 11 and 9 letters, respectively. Using a two-list scheme was suggested by Zhahai Stewart. == Examples == Each byte in a bytestring is encoded as a single word. A sequence of bytes is rendered in network byte order, from left to right. For example, the leftmost (i.e. byte 0) is considered "even" and is encoded using the PGP Even Word table. The next byte to the right (i.e. byte 1) is considered "odd" and is encoded using the PGP Odd Word table. This process repeats until all bytes are encoded. Thus, "E582" produces "topmost Istanbul", whereas "82E5" produces "miser travesty". A PGP public key fingerprint that displayed in hexadecimal as E582 94F2 E9A2 2748 6E8B 061B 31CC 528F D7FA 3F19 would display in PGP Words (the "biometric" fingerprint) as topmost Istanbul Pluto vagabond treadmill Pacific brackish dictator goldfish Medusa afflict bravado chatter revolver Dupont midsummer stopwatch whimsical cowbell bottomless The order of bytes in a bytestring depends on endianness. == Other word lists for data == There are several other word lists for conveying data in a clear unambiguous way via a voice channel: the NATO phonetic alphabet maps individual letters and digits to individual words the S/KEY system maps 64 bit numbers to 6 short words of 1 to 4 characters each from a publicly accessible 2048-word dictionary. The same dictionary is used in RFC 1760 and RFC 2289. the Diceware system maps five base-6 random digits (almost 13 bits of entropy) to a word from a dictionary of 7,776 distinct words. the Electronic Frontier Foundation has published a set of improved word lists based on the same concept FIPS 181: Automated Password Generator converts random numbers into somewhat pronounceable "words". mnemonic encoding converts 32 bits of data into 3 words from a vocabulary of 1626 words. what3words encodes geographic coordinates in 3 dictionary words. the BIP39 standard permits encoding a cryptographic key of fixed size (128 or 256 bits, usually the unencrypted master key of a Cryptocurrency wallet) into a short sequence of readable words known as the seed phrase, for the purpose of storing the key offline. This is used in cryptocurrencies such as Bitcoin or Monero. Like the PGP word list, the Bytewords standard maps each possible byte to a word. There is only one list, rather than two. The words are uniformly four letters long and can be uniquely identified by their first and last letters
Connection string
In computing, a connection string is a string that specifies information about a data source and the means of connecting to it. It is passed in code to an underlying driver or provider in order to initiate the connection. Whilst commonly used for a database connection, the data source could also be a spreadsheet or text file. The connection string may include attributes such as the name of the driver, server and database, as well as security information such as user name and password. == Examples == This example shows a PostgreSQL connection string for connecting to wikipedia.com with SSL and a connection timeout of 180 seconds: DRIVER={PostgreSQL Unicode};SERVER=www.wikipedia.com;SSL=true;SSLMode=require;DATABASE=wiki;UID=wikiuser;Connect Timeout=180;PWD=ashiknoor Users of Oracle databases can specify connection strings: on the command line (as in: sqlplus scott/tiger@connection_string ) via environment variables ($TWO_TASK in Unix-like environments; %TWO_TASK% in Microsoft Windows environments) in local configuration files (such as the default $ORACLE_HOME/network/admin.tnsnames.ora) in LDAP-capable directory services
Prix Ars Electronica
The Prix Ars Electronica is one of the best known and longest running yearly prizes in the field of electronic and interactive art, computer animation, digital culture and music. It has been awarded since 1987 by Ars Electronica (Linz, Austria). In 2005, the Golden Nica, the highest prize, was awarded in six categories: "Computer Animation/Visual Effects," "Digital Musics," "Interactive Art," "Net Vision," "Digital Communities" and the "u19" award for "freestyle computing." Each Golden Nica came with a prize of €10,000, apart from the u19 category, where the prize was €5,000. In each category, there are also Awards of Distinction and Honorary Mentions. The Golden Nica trophy is a replica of the Greek Nike of Samothrace. It is a handmade gold-plated wooden statuette that is approximately 35 cm high with a wingspan of about 20 cm. "Prix Ars Electronica" is a phrase composed of French, Latin and Spanish words, loosely translated as "Electronic Arts Prize." == Golden Nica winners == === Computer animation / film / vfx === The "Computer Graphics" category (1987–1994) was open to different kinds of computer images. The "Computer Animation" (1987–1997) was replaced by the current "Computer Animation/Visual Effects" category in 1998. ==== Computer Graphics ==== 1987 – Figur10 by Brian Reffin Smith, UK 1988 – The Battle by David Sherwin, US 1989 – Gramophone by Tamás Waliczky, HU 1990 – P-411-A by Manfred Mohr, Germany 1991 – Having encountered Eve for the second time, Adam begins to speak by Bill Woodard, US 1992 – RD Texture Buttons by Michael Kass and Andrew Witkin, US 1993 – Founders Series by Michael Tolson, US 1994 – Jellylife / Jellycycle / Jelly Locomotion by Michael Joaquin Grey, US ==== Computer Animation ==== 1987 – Luxo Jr. by John Lasseter, US 1988 – Red's Dream by John Lasseter, US 1989 – Broken Heart by Joan Staveley, US 1990 – Footprint by Mario Sasso and Nicola Sani, IT 1991 – Panspermia by Karl Sims, US 1992 – Liquid Selves / Primordial Dance by Karl Sims, US 1993 – Lakmé by Pascal Roulin, BE 1994 – Jurassic Park by Dennis Muren, Mark Dippé and Steve Williams, US/CA Distinction: Quarxs by Maurice Benayoun, FR Distinction: K.O. Kid by Marc Caro, FR 1995 – God's Little Monkey by David Atherton and Bob Sabiston, US 1996 – Toy Story by John Lasseter, Lee Unkrich and Ralph Eggleston, US 1997 – Dragonheart by Scott Squires, Industrial Light & Magic (ILM), US ==== Computer Animation/Visual Effects ==== 1998 – The Sitter by Liang-Yuan Wang, TW Titanic by Robert Legato and Digital Domain, US 1999 – Bunny by Chris Wedge, US What Dreams May Come by Mass Illusions, POP, Digital Domain, Vincent Ward, Stephen Simon and Barnet Bain, US 2000 – Maly Milos by Jakub Pistecky, CA Maaz by Christian Volckman, FR 2001 – Le Processus by Xavier de l’Hermuzičre and Philippe Grammaticopoulos, FR 2002 – Monsters, Inc. by Andrew Stanton, Lee Unkrich, Pete Docter and David Silverman, US 2003 – Tim Tom by Romain Segaud and Cristel Pougeoise, FR 2004 – Ryan by Chris Landreth, US. Distinction: Parenthèse from Francois Blondeau, Thibault Deloof, Jérémie Droulers, Christophe Stampe, France Distinction: Birthday Boy from Sejong Park, Australia 2005 – Fallen Art by Tomek Baginski, Poland. Distinction: The Incredibles from Pixar Distinction: City Paradise by Gaëlle Denis (UK), Passion Pictures (FR) 2006 – 458nm by Jan Bitzer, Ilija Brunck, Tom Weber, Filmakademie Baden-Württemberg, Germany. Distinction: Kein platz Für Gerold by Daniel Nocke / Studio Film Bilder, Germany Distinction: Negadon, the monster from Mars, by Jun Awazu, Japan 2007 – Codehunters by Ben Hibon, (UK) 2008 – Madame Tutli-Putli by Chris Lavis, Maciek Szczerbowski. (Directors), Jason Walker (Special Visual Effects), National Film Board of Canada 2009 – HA'Aki by Iriz Pääbo, National Film Board of Canada 2010 – Nuit Blanche by Arev Manoukian (Director), Marc-André Gray (Visual Effects Artist), National Film Board of Canada 2011 – Metachaos by Alessandro Bavari (IT) 2012 – Rear Window Loop by Jeff Desom (LU) Distinction: Caldera by Evan Viera/Orchid Animation (US) Distinction: Rise of the Planet of the Apes by Weta Digital (NZ)/Twentieth Century Fox 2013 – Forms by Quayola (IT), Memo Akten (TR) Distinction: Duku Spacemarines by La Mécanique du Plastique (FR) Distinction: Oh Willy… by Emma De Swaef (BE), Marc James Roels (BE) / Beast Animation 2014 – Walking City by Universal Everything (UK) 2015 – Temps Mort by Alex Verhaest (BE)[1] Distinction: Bär by Pascal Floerks (DE) Distinction: The Reflection of Power by Mihai Grecu (RO/HU) === Digital Music === This category is for those making electronic music and sound art through digital means. From 1987 to 1998 the category was known as "Computer music." Two Golden Nicas were awarded in 1987, and none in 1990. There was no Computer Music category in 1991. 1987 – Peter Gabriel and Jean-Claude Risset 1988 – Denis Smalley 1989 – Kaija Saariaho 1990 – None 1991 – Category omitted 1992 – Alejandro Viñao 1993 – Bernard Parmegiani 1994 – Ludger Brümmer Distinction: Jonathan Impett 1995 – Trevor Wishart 1996 – Robert Normandeau 1997 – Matt Heckert 1998 – Peter Bosch and Simone Simons (joint award) 1999 – Come to Daddy by Aphex Twin (Richard D. James) and Chris Cunningham (joint award) Distinction: Birthdays by Ikue Mori (JP) Distinction: Mego (label), Hotel Paral.lel by Christian Fennesz, Seven Tons For Free by Peter Rehberg (a.k.a. Pita) 2000 – 20' to 2000 by Carsten Nicolai Distinction: Minidisc by Gescom Distinction: Outside the Circle of Fire by Chris Watson 2001 – Matrix by Ryoji Ikeda 2002 – Man'yo Wounded 2001 by Yasunao Tone 2003 – Ami Yoshida, Sachiko M and Utah Kawasaki (joint award) 2004 – Banlieue du Vide by Thomas Köner 2005 – TEO! A Sonic Sculpture by Maryanne Amacher 2006 – L'île ré-sonante by Éliane Radigue 2007 – Reverse-Simulation Music by Mashiro Miwa 2008 – Reactable by Sergi Jordà (ES), Martin Kaltenbrunner (AT), Günter Geiger (AT) and Marcos Alonso (ES) 2009 – Speeds of Time versions 1 and 2 by Bill Fontana (US) 2010 – rheo: 5 horizons by Ryoichi Kurokawa (JP) 2011 – Energy Field by Jana Winderen (NO) 2012 – "Crystal Sounds of a Synchrotron" by Jo Thomas (GB) 2013 – frequencies (a) by Nicolas Bernier (CA) Distinction: SjQ++ by SjQ++ (JP) Distinction: Borderlands Granular by Chris Carlson (US) 2015 – Chijikinkutsu by Nelo Akamatsu (JP) Distinction: Drumming is an elastic concept by Josef Klammer (AT) Distinction: Under Way by Douglas Henderson (DE) 2017 – Not Your World Music: Noise In South East Asia by Cedrik Fermont (CD/BE/DE), Dimitri della Faille (BE/CA) Distinction: Gamelan Wizard by Lucas Abela (AU), Wukir Suryadi (ID) und Rully Shabara (ID) Distinction: Corpus Nil by Marco Donnarumma (DE/IT) === Hybrid art === 2007 – Symbiotica 2008 – Pollstream – Nuage Vert by Helen Evans (FR/UK) and Heiko Hansen (FR/DE) HeHe 2009 – Natural History of the Enigma by Eduardo Kac (US) 2010 – Ear on Arm by Stelarc (AU) 2011 – May the Horse Live in me by Art Orienté Objet (FR) 2012 – Bacterial radio by Joe Davis (US) Distinction: Free Universal Construction Kit (F.U.C.K.) by Golan Levin and Shawn Sims 2013 – Cosmopolitan Chicken Project, Koen Vanmechelen (BE) 2015 – Plantas Autofotosintéticas, Gilberto Esparza (MX) 2017 – K-9_topology, Maja Smrekar (SI) === [the next idea] voestalpine Art and Technology Grant === 2009 – Open_Sailing by Open_Sailing Crew led by Cesar Harada. 2010 – Hostage by [Frederik De Wilde]. 2011 – Choke Point Project by P2P Foundation (NL). 2012 – qaul.net – tools for the next revolution by Christoph Wachter & Mathias Jud 2013 – Hyperform by Marcelo Coelho (BR), Skylar Tibbits (US), Natan Linder (IL), Yoav Reaches (IL) Honorary Mentions: GravityLight by Martin Riddiford (GB), Jim Reeves (GB) 2014 – BlindMaps by Markus Schmeiduch, Andrew Spitz and Ruben van der Vleuten 2015 – SOYA C(O)U(L)TURE by XXLab (ID) – Irene Agrivina Widyaningrum, Asa Rahmana, Ratna Djuwita, Eka Jayani Ayuningtias, Atinna Rizqiana === Interactive Art === Prizes in the category of interactive art have been awarded since 1990. This category applies to many categories of works, including installations and performances, characterized by audience participation, virtual reality, multimedia and telecommunication. 1990 – Videoplace installation by Myron Krueger 1991 – Think About the People Now project by Paul Sermon 1992 – Home of the Brain installation by Monika Fleischmann and Wolfgang Strauss 1993 – Simulationsraum-Mosaik mobiler Datenklänge (smdk) installation by Knowbotic Research 1994 – A-Volve environment by Christa Sommerer and Laurent Mignonneau 1995 – the concept of Hypertext, attributed to Tim Berners-Lee 1996 – Global Interior Project installation by Masaki Fujihata 1997 – Music Plays Images X Images Play Music concert by Ryuichi Sakamoto and Toshio Iwai 1998 – World Skin, a Photo Safari in the Land of War installation by Jean-Baptiste Barrière and Maurice Benayoun 1999 – Difference Engine #3 by construct and Lynn Hershman 2000 – Vectorial Elevati
Visopsys
Visopsys (Visual Operating System), is an operating system, written by Andy McLaughlin. Development of the operating system began in 1997. The operating system is licensed under the GNU GPL, with the headers and libraries under the less restrictive LGPL license. It runs on the 32-bit IA-32 architecture. It features a multitasking kernel, supports asynchronous I/O and the FAT line of file systems. It requires a Pentium processor. == History == The development of Visopsys began in 1997, being written by Andy McLaughlin. The first public release of the Operating System was on 2 March 2001, with version 0.1. In this release, Visopsys was a 32 bit operating system, supporting preemptive multitasking and virtual memory. == System overview == Visopsys uses a monolithic kernel, written in the C programming language, with elements of assembly language for certain interactions with the hardware. The operating system supports a graphical user interface, with a small C library.
Usage share of operating systems
The usage share of an operating system is the percentage of computers running that operating system (OS). These statistics are estimates as wide scale OS usage data is difficult to obtain and measure. Reliable primary sources are limited and data collection methodology is not formally agreed. Currently devices connected to the internet allow for web data collection to approximately measure OS usage. As of December 2025, Android, which uses the Linux kernel, is the world's most popular operating system with 38.94% of the global market, followed by Windows with 29.99%, iOS with 15.66%, macOS with 2.14%, and other operating systems with 10.78%. This is for all device types excluding embedded devices. For smartphones and other mobile devices, Android has 72% market share, and Apple's iOS has 28%. For desktop computers and laptops, Microsoft Windows has 60.8%, followed by unknown operating systems at 19.7%, Mac OS at 14.4%, desktop Linux at 3.2%, then Google's ChromeOS at 1.6%, as of March 2026. For tablets, Apple's iPadOS (a variant of iOS) has 52% share and Android has 48% worldwide. For the top 500 most powerful supercomputers, Linux distributions have had 100% of the market share since 2017. The global server operating system market share has Linux leading with a 63.1% marketshare, followed by Windows, Unix and other operating systems. Linux is also most used for web servers, and the most common Linux distribution is Ubuntu, followed by Debian. Linux has almost caught up with the second-most popular (desktop) OS, macOS, in some regions, such as in South America, and in Asia it's at 6.4% (7% with ChromeOS) vs 9.7% for macOS. In the US, ChromeOS is third at 5.5%, followed by (desktop) Linux at 4.3%. The most numerous type of device with an operating system are embedded systems. Not all embedded systems have operating systems, instead running their application code on the "bare metal"; of those that do have operating systems, a high percentage are standalone or do not have a web browser, which makes their usage share difficult to measure. Some operating systems used in embedded systems are more widely used than some of those mentioned above; for example, modern Intel microprocessors contain an embedded management processor running a version of the Minix operating system. == Worldwide device shipments == Shipments (to stores) do not necessarily translate to sales to consumers, therefore suggesting the numbers indicate popularity and/or usage could be misleading. Not only do smartphones sell in higher numbers than PCs, but also a lot more by dollar value, with the gap only projected to widen, to well over double. According to Gartner, the following is the worldwide device shipments (referring to wholesale) by operating system from 2012 to 2016, which includes smartphones, tablets, laptops and PCs together. On 27 January 2016, Paul Thurrott summarized the operating system market, the day after Apple announced "one billion devices": Apple's "active installed base" is now one billion devices. [..] Granted, some of those Apple devices were probably sold into the marketplace years ago. But that 1 billion figure can and should be compared to the numbers Microsoft touts for Windows 10 (200 million, most recently) or Windows more generally (1.5 billion active users, a number that hasn’t moved, magically, in years), and that Google touts for Android (over 1.4 billion, as of September). My understanding of iOS is that the user base was previously thought to be around 800 million strong, and when you factor out Macs and other non-iOS Apple devices, that's probably about right. But as you can see, there are three big personal computing platforms. And only one of them is actually declining. We’ll see how Windows 10 fares over the long term, but even if Microsoft hits the 1 billion figure in 1-2 years as promised, it will by then still be the smallest of those three platforms. In 2018, Apple stopped revealing unit sales in its reports. Since 2018, the company have been publishing only revenues per device models which, nonetheless, allowed the analysers to extrapolate the unit sales from the model revenues by applying the wholesale device prices. Other hardware manufacturers usually do not report unit sales. === PC shipments === For 2015 (and earlier), Gartner reports for "the year, worldwide PC shipments declined for the fourth consecutive year, which started in 2012 with the launch of tablets" with an 8% decline in PC sales for 2015 (not including cumulative decline in sales over the previous years). Microsoft backed away from their goal of one billion Windows 10 devices in three years (or "by the middle of 2018") and reported on 26 September 2016 that Windows 10 was running on over 400 million devices, and in March 2019, on more than 800 million. In May 2020, Gartner predicted further decline in all market segments for 2020 due to COVID-19, predicting a decline of 13.6% for all devices. while the "Work from Home Trend Saved PC Market from Collapse", with only a decline of 10.5% predicted for PCs. However, in the end, according to Gartner, PC shipments grew 10.7% in the fourth quarter of 2020 and reached 275 million units in 2020, a 4.8% increase from 2019 and the highest growth in ten years." Apple in 4th place for PCs had the largest growth in shipments for a company in Q4 of 31.3%, while "the fourth quarter of 2020 was another remarkable period of growth for Chromebooks, with shipments increasing around 200% year over year to reach 11.7 million units. In 2020, Chromebook shipments increased over 80% to total nearly 30 million units, largely due to demand from the North American education market." Chromebooks sold more (30 million) than Apple's Macs worldwide (22.5 million) in pandemic year 2020. According to the Catalyst group, the year 2021 had record high PC shipments with total shipments of 341 million units (including Chromebooks), 15% higher than 2020 and 27% higher than 2019, while being the largest shipment total since 2012. According to Gartner, worldwide PC shipments declined by 16.2% in 2022, the largest annual decrease since the mid-1990s, due to geopolitical, economic, and supply chain challenges. In 2024 and 2025, due to lower adoption of Windows 11 and Microsoft ending its support to Windows 10, the number of PCs shipped with pre-installed Windows OS dropped. Pundits attribute the low Windows 11 acceptance to its steep hardware requirements and especially the TPM 2.0 ready chipset requirement and the 2024 CrowdStrike-related IT outages. Meanwhile, the macOS device market share in PC device shipments increased to new heights, with improved numbers seen for Linux devices too. In Q3 2025, the macOS pre-installed device shipments increased by 14.9% year-over-year (YoY), while the overall PC-shipments increased only by 8.1%, in Q2 2025, it grew 21.4% YoY while the global PC-shipments increased only by 6.5%, and in Q1 2025, it grew 7% YoY while the global PC-shipments increased by 4.8%. === Tablet computers shipments === In 2015, eMarketer estimated at the beginning of the year that the tablet installed base would hit one billion for the first time (with China's use at 328 million, which Google Play doesn't serve or track, and the United States's use second at 156 million). At the end of the year, because of cheap tablets – not counted by all analysts – that goal was met (even excluding cumulative sales of previous years) as: Sales quintupled to an expected 1 billion units worldwide this year, from 216 million units in 2014, according to projections from the Envisioneering Group. While that number is far higher than the 200-plus million units globally projected by research firms IDC, Gartner and Forrester, Envisioneering analyst Richard Doherty says the rival estimates miss all the cheap Asian knockoff tablets that have been churning off assembly lines.[..] Forrester says its definition of tablets "is relatively narrow" while IDC says it includes some tablets by Amazon — but not all.[..] The top tech purchase of the year continued to be the smartphone, with an expected 1.5 billion sold worldwide, according to projections from researcher IDC. Last year saw some 1.2 billion sold.[..] Computers didn’t fare as well, despite the introduction of Microsoft's latest software upgrade, Windows 10, and the expected but not realized bump it would provide for consumers looking to skip the upgrade and just get a new computer instead. Some 281 million PCs were expected to be sold, according to IDC, down from 308 million in 2014. Folks tend to be happy with the older computers and keep them for longer, as more of our daily computing activities have moved to the smartphone.[..] While Windows 10 got good reviews from tech critics, only 11% of the 1-billion-plus Windows user base opted to do the upgrade, according to Microsoft. This suggests Microsoft has a ways to go before the software gets "hit" status. Apple's new operating system El Capitan has been
Shape factor (image analysis and microscopy)
Shape factors are dimensionless quantities used in image analysis and microscopy that numerically describe the shape of a particle, independent of its size. Shape factors are calculated from measured dimensions, such as diameter, chord lengths, area, perimeter, centroid, moments, etc. The dimensions of the particles are usually measured from two-dimensional cross-sections or projections, as in a microscope field, but shape factors also apply to three-dimensional objects. The particles could be the grains in a metallurgical or ceramic microstructure, or the microorganisms in a culture, for example. The dimensionless quantities often represent the degree of deviation from an ideal shape, such as a circle, sphere or equilateral polyhedron. Shape factors are often normalized, that is, the value ranges from zero to one. A shape factor equal to one usually represents an ideal case or maximum symmetry, such as a circle, sphere, square or cube. == Aspect ratio == The most common shape factor is the aspect ratio, a function of the largest diameter and the smallest diameter orthogonal to it: A R = d min d max {\displaystyle A_{R}={\frac {d_{\min }}{d_{\max }}}} The normalized aspect ratio varies from approaching zero for a very elongated particle, such as a grain in a cold-worked metal, to near unity for an equiaxed grain. The reciprocal of the right side of the above equation is also used, such that the AR varies from one to approaching infinity. == Circularity == Another very common shape factor is the circularity (or isoperimetric quotient), a function of the perimeter P and the area A: f circ = 4 π A P 2 {\displaystyle f_{\text{circ}}={\frac {4\pi A}{P^{2}}}} The circularity of a circle is 1, and much less than one for a starfish footprint. The reciprocal of the circularity equation is also used, such that fcirc varies from one for a circle to infinity. == Elongation shape factor == The less-common elongation shape factor is defined as the square root of the ratio of the two second moments in of the particle around its principal axes. f elong = i 2 i 1 {\displaystyle f_{\text{elong}}={\sqrt {\frac {i_{2}}{i_{1}}}}} == Compactness shape factor == The compactness shape factor is a function of the polar second moment in of a particle and a circle of equal area A. f comp = A 2 2 π i 1 2 + i 2 2 {\displaystyle f_{\text{comp}}={\frac {A^{2}}{2\pi {\sqrt {{i_{1}}^{2}+{i_{2}}^{2}}}}}} The fcomp of a circle is one, and much less than one for the cross-section of an I-beam. == Waviness shape factor == The waviness shape factor of the perimeter is a function of the convex portion Pcvx of the perimeter to the total. f wav = P cvx P {\displaystyle f_{\text{wav}}={\frac {P_{\text{cvx}}}{P}}} Some properties of metals and ceramics, such as fracture toughness, have been linked to grain shapes. == An application of shape factors == Greenland, the largest island in the world, has an area of 2,166,086 km2; a coastline (perimeter) of 39,330 km; a north–south length of 2670 km; and an east–west length of 1290 km. The aspect ratio of Greenland is A R = 1290 2670 = 0.483 {\displaystyle A_{R}={\frac {1290}{2670}}=0.483} The circularity of Greenland is f circ = 4 π ( 2166086 ) 39330 2 = 0.0176. {\displaystyle f_{\text{circ}}={\frac {4\pi (2166086)}{39330^{2}}}=0.0176.} The aspect ratio is agreeable with an eyeball-estimate on a globe. Such an estimate on a typical flat map, using the Mercator projection, would be less accurate due to the distorted scale at high latitudes. The circularity is deceptively low, due to the fjords that give Greenland a very jagged coastline (see the coastline paradox). A low value of circularity does not necessarily indicate a lack of symmetry, and shape factors are not limited to microscopic objects.
Far-Play
Far-Play (stylized fAR-Play, from augmented reality) was a software platform developed at the University of Alberta, for creating location-based, scavenger-hunt style games which use the GPS and web-connectivity features of a player's smartphone. According to the development team, "our long-term objective is to develop a general framework that supports the implementation of AARGs that are fun to play and also educational". It utilizes Layar, an augmented reality smartphone application, QR codes located at particular real-world sites, or a phone's web browser, to facilitate games which require players to be in close physical proximity to predefined "nodes". A node, referred to by the developers as a Virtual Point of Interest (vPOI), is a point in space defined by a set of map coordinates; fAR-Play uses the GPS function of a player's smartphone — or, for indoor games, which are not easily tracked by GPS satellites, specially-created QR codes— to confirm that they are adequately near a given node. Once a player is within a node's proximity, Layar's various augmented reality features can be utilized to display a range of extra content overlaid upon the physical play-space or launch another application for extra functionality. == Development and features == fAR-Play began development in 2008, emerging from a collaborative project undertaken by a group of University of Alberta students from the Computer Science and Humanities Computing departments. fAR-Play is still under development, but a beta version is available for testing by request. fAR-Play's development is managed by a team of interdisciplinary professors and students at the University of Alberta. Currently, the developing team's roster includes Supervising Professors Geoffrey Rockwell and Eleni Stroulia, Developers Lucio Gutierrez and Matthew Delaney, and Website Developers Calen Henry and Garry Wong. === Technology === fAR-Play relies on a number of open- and closed-source web technologies as tools to create, and enhance the users' experience. Layar is the recommended client-side frontend for delivering game content to the player; it is available on Android and iOS, which covers over 91% of smartphones. While Layar is not a requirement to play fAR-Play games, the application does supply additional augmented reality functionality; Layar also includes a built-in QR scanner. Depending on the design of the particular game, the player may instead use a dedicated QR code scanner; the developers recommend BeeTagg, but any such application will do. Layar or a QR code scanner are the maximum software requirements to play a fAR-Play game, making implementation of games on a wide variety of platforms relatively straightforward. fAR-Play games can also be designed for play strictly within a mobile phone's web browser. On the server side, fAR-Play's engine is composed of an Apache server which manages the system's web interface, including the mobile and desktop versions of the fAR-Play website, and a Java-based REST framework for managing the database of nodes. === Features === As a platform for designing AR games, as opposed to an AR game itself, fAR-Play offers little in the way of explicit shapes or patterns for games to take; instead, these elements are left to the game designer or players to develop. However, the nonspecific nature of nodes, the many options they offer for content delivery, and the open design of the platform are such that these elements can be developed extensively. Functionally, fAR-Play is a tool for tracking arbitrary points in space and a given player's proximity to them; what it does beyond that is up to the developers' and players' discretion. However, the fAR-Play website contains a leaderboard which tracks registered user's total scores. Players are assigned levels based on their total score, ranging from Novice — Super Player. Player profiles will display nodes that the player has recently caught, and any achievements the player has gained. Additionally, players can share their adventure progress, achievements, and the capture of vPOIs on Facebook. == How to play == In order to participate in the locative aspects of fAR-Play games, users must have an Android or iOS mobile device and access to wireless internet. Players can participate in fAR-Play anonymously, or create and sign into a fAR-Play account. Those who choose to play anonymously will lose the ability to track their progress across multiple games. When signed in, the player is presented with a list of games that are currently available for play. Each game includes a brief description and the various "adventures" available to the player. Once the game has been started, the player has three different methods for capturing nodes: they may scan a QR in the physical space, discover a node through the Layar camera virtual view, or receive a link in their device's web browser. === QR codes and Layar === QR codes can only be used as a method for capturing nodes and initiating games when there is a physical code present. In order to scan a QR code, players are required to have an application which can capture and recognize QR codes. If the player is utilizing a QR scanning application that has a built in browser, they will be required to log into fAR-Play through the app. Layar is a free to download augmented reality app, containing a built in QR code scanner, which enables its users to participate in fAR-Play games. === Capturing nodes === Layar permits the player to see nodes on their mobile device, guiding the player to their goal. Using this application, the player is able to navigate to their objective with map provided by Google Maps' API or by using their camera — Layar overlays a virtual image onto the real-world scene presented by the camera. The representations on screen expand in size as the player approaches the node destination, simulating relative distance. If the player taps any of the nodes that are presented on the screen, they will be provided additional information about that node, including the node's name and a brief description. Nodes can be captured by tapping the "capture" button. === Playing on browsers === The player can also play fAR-Play games within their mobile device's browser. By visiting https://archive.today/20131123223038/http://farplay.ualberta.ca/far-play/ on a mobile device, players will be presented with a fully realized user interface, permitting full interaction with the games. The player can capture the in game vPOIs through their browser by tapping the "nodes" button. This will bring up a list of all the accessible nodes, complete with a brief description for each location. By clicking on one of the nodes, the player is shown to a screen with a mapped location of the vPOI, an in-depth description of it, and hints. At the top of the page, the player can tap "CAPTURE THIS NODE" and advance in the game. When attempting to capture a node, the developer may or may not associate a challenge with the node. For example, in the game "Zombies ate my Campus", when players are attempting to capture a node, they're presented with a multiple choice question associated with the current node. === Game types === Players complete an adventure when they have captured all of the nodes within it. fAR-Play provides two game modes: in a Virtual Scavenger Hunt, nodes must be captured in a specific order; in a Virtual Treasure Hunt, the order is unimportant. == Existing fAR-Play games == Games currently available through fAR-Play include: Giselle Ever After Thought Hub Comics Arts Capture Challenge Pioneering Edmonton The Intelliphone Challenge A Tour of Atwater Zombies ate my Campus == For developers == fAR-Play's ultimate goal is to provide a simple, effective platform for the creation of locative augmented reality games, but the developer tools are still under active development and not openly available to the public. Access can be granted on a case-by-case basis, however, and a developer's manual is available. Users with development privileges can create new games or edit their existing games, in addition to playing their own or others' games. === Adventures === Games that are developed with fAR-Play are segmented into components called "Adventures". To progress through each game adventure, the player must reach and capture virtual points of interest, referred to in the game as vPOIs. In order to capture a vPOI, the player must travel to a physical location that is set by the developer. It is the developer's choice to include a challenge question to capture the vPOI, though it is not mandatory. A deduction of points can be implemented if the player submits an incorrect answer to a challenge question. === Points and achievements === Each of the nodes will reward the player with a predetermined number of points once they have been captured by the player. These points are added to the player's total points. Each of the adventures that are created require a predetermined number of vPOIs