Summary

HandWiki is the world's largest wiki-style encyclopedia dedicated to science, technology and computing. It allows you to create and edit articles as long as you have external citations and login account. In addition, this is a content management environment that can be used for collaborative editing of original scholarly content, such as books, manuals, monographs and tutorials.

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Automatic Vehicle Location
Automatic vehicle location (AVL or ~locating; telelocating in EU) is a means for automatically determining and transmitting the geographic location of a vehicle. This vehicle location data, from one or more vehicles, may then be collected by a vehicle tracking system to manage an overview of vehicle travel. As of 2017, GPS technology has reached the point of having the transmitting device be smaller than the size of a human thumb (thus easier to conceal), able to run 6 months or more between battery charges, easy to communicate with smartphones (merely requiring a duplicate SIM card from one's mobile phone carrier in most cases) — all for less than $20 USD. Most commonly, the location is determined using GPS and the transmission mechanism is SMS, GPRS, or a satellite or terrestrial radio from the vehicle to a radio receiver. A single antenna unit covering all the needed frequency bands can be employed. GSM and EVDO are the most common services applied, because of the low data rate needed for AVL, and the low cost and near-ubiquitous nature of these public networks. The low bandwidth requirements also allow for satellite technology to receive telemetry data at a moderately higher cost, but across a global coverage area and into very remote locations not covered well by terrestrial radio or public carriers. Other options for determining actual location, for example in environments where GPS illumination is poor, are dead reckoning, i.e. inertial navigation, or active RFID systems or cooperative RTLS systems. These systems may be applied in combination in some cases. In addition, terrestrial radio positioning systems using a low frequency switched packet radio network have also been used as an alternative to GPS based systems.
  • 831
  • 14 Oct 2022
Topic Review
Ecliptic Coordinate System
The ecliptic coordinate system is a celestial coordinate system commonly used for representing the apparent positions, orbits, and pole orientations of Solar System objects. Because most planets (except Mercury) and many small Solar System bodies have orbits with only slight inclinations to the ecliptic, using it as the fundamental plane is convenient. The system's origin can be the center of either the Sun or Earth, its primary direction is towards the vernal (March) equinox, and it has a right-hand convention. It may be implemented in spherical or rectangular coordinates.
  • 6.9K
  • 19 Oct 2022
Topic Review
History of the Portable Document Format (PDF)
The Portable Document Format was created in the early 1990s by Adobe Systems, introduced at the Windows and OS|2 Conference in January 1993 and remained a proprietary format until it was released as an open standard in 2008. Since then, it is under control of International Organization for Standardization Committee of volunteer industry experts. PDF was developed to share documents, including text formatting and inline images, among computer users of disparate platforms who may not have access to mutually-compatible application software.It was created by a research and developement team called Camelot, led by Adobe's co-founder John Warnock. PDF was one among a number of competing formats such as DjVu, Envoy, Common Ground Digital Paper, Farallon Replica and even Adobe's own PostScript format. In those early years before the rise of the World Wide Web and HTML documents, PDF was popular mainly in desktop publishing workflows. PDF's adoption in the early days of the format's history was slow. Adobe Acrobat, Adobe's suite for reading and creating PDF files, was not freely available; early versions of PDF had no support for external hyperlinks, reducing its usefulness on the Internet; the larger size of a PDF document compared to plain text required longer download times over the slower modems common at the time; and rendering PDF files was slow on the less powerful machines of the day. Adobe distributed its Adobe Reader (now Acrobat Reader) program free of charge from version 2.0 onwards, and continued supporting the original PDF, which eventually became the de facto standard for fixed-format electronic documents. In 2008 Adobe Systems' PDF Reference 1.7 became ISO 32000:1:2008. Thereafter, further development of PDF (including PDF 2.0) is conducted by ISO's TC 171 SC 2 WG 8 with the participation of Adobe Systems and other subject matter experts.
  • 3.4K
  • 14 Oct 2022
Topic Review
C. V. Subramanian
Chirayathumadom Venkatachalier Subramanian (11 August 1924–5 February 2016), popularly known as CVS, was an Indian mycologist, taxonomist and plant pathologist, known for his work on the classification of Fungi imperfecti, a group of fungi classified separately due to lack of specific taxonomic characteristics. He authored one monograph, Hyphomycetes: An Account of Indian Species, Except Cercosporae and three books, Hyphomycetes, taxonomy and biology, Moulds, Mushrooms and Men and Soil microfungi of Israel, besides several articles published in peer reviewed journals. He was a recipient of many honours including the Rafi Ahmed Kidwai Award of the Indian Council of Agricultural Research, the Janaki Ammal National Award of the Government of India and seven species of fungi have been named after him. The Council of Scientific and Industrial Research, the apex agency of the Government of India for scientific research, awarded him the Shanti Swarup Bhatnagar Prize for Science and Technology, one of the highest Indian science awards, in 1965, for his contributions to biological sciences.
  • 1.1K
  • 14 Oct 2022
Topic Review
Reticle
A reticle, or reticule also known as a graticule, is a pattern of fine lines or markings built into the eyepiece of an optical device such as a telescopic sight, spotting scope, theodolite, optical microscope or the screen of an oscilloscope, to provide measurement references during visual inspections. Today, engraved lines or embedded fibers may be replaced by a digital image superimposed on a screen or eyepiece. Both terms may be used to describe any set of patterns used for aiding visual measurements and calibrations, but in modern use reticle is most commonly used for weapon sights, while graticule is more widely used for non-weapon measuring instruments such as oscilloscope display, astronomic telescopes, microscopes and slides, surveying instruments and other similar devices. There are many variations of reticle pattern; this article concerns itself mainly with the most rudimentary reticle: the crosshair. Crosshairs are typically represented as a pair of perpendicularly intersecting lines in the shape of a cross, "+", though many variations of additional features exist including dots, posts, concentric circles/horseshoes, chevrons, graduated markings, or a combination of above. Most commonly associated with telescopic sights for aiming firearms, crosshairs are also common in optical instruments used for astronomy and surveying, and are also popular in graphical user interfaces as a precision pointer. The reticle is said to have been invented by Robert Hooke, and dates to the 17th century. Another candidate as inventor is the amateur astronomer William Gascoigne, who predated Hooke.
  • 1.5K
  • 14 Oct 2022
Topic Review
Desert Island
A deserted island or uninhabited island is an island that is not permanently populated by humans. Uninhabited islands are often used in movies or stories about shipwrecked people, and are also used as stereotypes for the idea of "paradise". Some uninhabited islands are protected as nature reserves and some are privately owned. Devon Island in Canada is claimed to be the largest uninhabited island in the world. Small coral atolls or islands usually have no source of fresh water, but at times a fresh water lens (Ghyben–Herzberg lens) can be reached with a well.
  • 5.1K
  • 14 Oct 2022
Topic Review
Genetics of Posttraumatic Stress Disorder
The potential Genetic influences of post-traumatic stress disorder are ill understood due to the limitations of any genetic study of mental illness; in that it cannot be ethically induced in selected groups. So all studies must use naturally occurring groups with genetic similarities and difference, thus the amount of data is limited. However, Genetics play some role in the development of PTSD. Approximately 30% of the variance in PTSD is caused from genetics alone. For twin pairs exposed to combat in Vietnam, having a monozygotic (identical) twin with PTSD was associated with an increased risk of the co-twin's having PTSD compared to twins that were dizygotic (non-identical twins).
  • 479
  • 14 Oct 2022
Topic Review
Osiris
Osiris Serverless Portal System (usually abbreviated as Osiris sps or Osiris) is a freeware program used to create web portals distributed via peer-to-peer networking (P2P) and autonomous from centralized servers. It is available for Microsoft Windows and Linux operating systems. Unlike common tools used to publish information on the Internet, such as content management systems, Internet forums or blogs based on a centralized system, the data of an Osiris portal are shared (via P2P) between all its participants. Because all the contents necessary for navigation are replicated on every computer, the portal can be used without a central server. Thus, the portal is always accessible because it is immune to denial of service attacks, Internet service provider limitations (such as traffic shaping and censorship) and hardware failure. In this way, a web portal can be operated at very low costs and free from external control.
  • 817
  • 14 Oct 2022
Topic Review
Oneirology
Oneirology (/ɒnɪˈrɒlədʒi/; from Greek ὄνειρον, oneiron, "dream"; and -λογία, -logia, "the study of") is the scientific study of dreams. Current research seeks correlations between dreaming and current knowledge about the functions of the brain, as well as understanding of how the brain works during dreaming as pertains to memory formation and mental disorders. The study of oneirology can be distinguished from dream interpretation in that the aim is to quantitatively study the process of dreams instead of analyzing the meaning behind them.
  • 1.9K
  • 14 Oct 2022
Topic Review
Vice News
Vice News (stylized as VICE News) is Vice Media's current affairs channel, producing daily documentary essays and video through its website and YouTube channel. It promotes itself on its coverage of "under-reported stories". Vice News was created in December 2013 and is based in New York City , though it has bureaus worldwide.
  • 1.5K
  • 14 Oct 2022
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