SUMMARY / RELATED TOPICS

Charles Babbage

Charles Babbage was an English polymath. A mathematician, philosopher and mechanical engineer, Babbage originated the concept of a digital programmable computer. Considered by some to be a "father of the computer", Babbage is credited with inventing the first mechanical computer that led to more complex electronic designs, though all the essential ideas of modern computers are to be found in Babbage's Analytical Engine, his varied work in other fields has led him to be described as "pre-eminent" among the many polymaths of his century. Parts of Babbage's incomplete mechanisms are on display in the Science Museum in London. In 1991, a functioning difference engine was constructed from Babbage's original plans. Built to tolerances achievable in the 19th century, the success of the finished engine indicated that Babbage's machine would have worked. Babbage's birthplace is disputed, but according to the Oxford Dictionary of National Biography he was most born at 44 Crosby Row, Walworth Road, England.

A blue plaque on the junction of Larcom Street and Walworth Road commemorates the event. His date of birth was given in his obituary in The Times as 26 December 1792; the parish register of St. Mary's, London, shows that Babbage was baptised on 6 January 1792, supporting a birth year of 1791. Babbage was one of four children of Betsy Plumleigh Teape, his father was a banking partner of William Praed in founding Praed's & Co. of Fleet Street, London, in 1801. In 1808, the Babbage family moved into the old Rowdens house in East Teignmouth. Around the age of eight, Babbage was sent to a country school in Alphington near Exeter to recover from a life-threatening fever. For a short time he attended King Edward VI Grammar School in Totnes, South Devon, but his health forced him back to private tutors for a time. Babbage joined the 30-student Holmwood Academy, in Baker Street, Middlesex, under the Reverend Stephen Freeman; the academy had a library. He studied with two more private tutors after leaving the academy.

The first was a clergyman near Cambridge. He was brought home, to study at the Totnes school: this was at age 16 or 17; the second was an Oxford tutor, under whom Babbage reached a level in Classics sufficient to be accepted by Cambridge. Babbage arrived at Trinity College, Cambridge, in October 1810, he was self-taught in some parts of contemporary mathematics. As a result, he was disappointed in the standard mathematical instruction available at the university. Babbage, John Herschel, George Peacock, several other friends formed the Analytical Society in 1812; as a student, Babbage was a member of other societies such as The Ghost Club, concerned with investigating supernatural phenomena, the Extractors Club, dedicated to liberating its members from the madhouse, should any be committed to one. In 1812 Babbage transferred to Cambridge, he did not graduate with honours. He instead received a degree without examination in 1814, he had defended a thesis, considered blasphemous in the preliminary public disputation.

Considering his reputation, Babbage made progress. He lectured to the Royal Institution on astronomy in 1815, was elected a Fellow of the Royal Society in 1816. After graduation, on the other hand, he applied for positions unsuccessfully, had little in the way of career. In 1816 he was a candidate for a teaching job at Haileybury College. In 1819, Babbage and Herschel visited Paris and the Society of Arcueil, meeting leading French mathematicians and physicists; that year Babbage applied to be professor at the University of Edinburgh, with the recommendation of Pierre Simon Laplace. With Herschel, Babbage worked on the electrodynamics of Arago's rotations, publishing in 1825, their explanations were only transitional, being broadened by Michael Faraday. The phenomena are now part of the theory of eddy currents, Babbage and Herschel missed some of the clues to unification of electromagnetic theory, staying close to Ampère's force law. Babbage purchased the actuarial tables of George Barrett, who died in 1821 leaving unpublished work, surveyed the field in 1826 in Comparative View of the Various Institutions for the Assurance of Lives.

This interest followed a project to set up an insurance company, prompted by Francis Baily and mooted in 1824, but not carried out. Babbage did calculate actuarial tables for that scheme, using Equitable Society mortality data from 1762 onwards. During this whole period Babbage depended awkwardly on his father's support, given his father's attitude to his early marriage, of 1814: he and Edward Ryan wedded the Whitmore sisters, he made a home in Marylebone in London, founded a large family. On his father's death in 1827, Babbage inherited a large estate. After his wife's death in the same year he spent time travelling. In Italy he met Leopold II, Grand Duke of Tuscany, foreshadowing a visit to Piedmont. In April 1828 he was in Rome, relying on Herschel to manage the difference engine project, when he heard that he had become professor at Cambridge, a positi

RenderMan Interface Specification

The RenderMan Interface Specification, or RISpec in short, is an open API developed by Pixar Animation Studios to describe three-dimensional scenes and turn them into digital photorealistic images. It includes the RenderMan Shading Language; as Pixar's technical specification for a standard communications protocol between modeling programs and rendering programs capable of producing photorealistic-quality images, RISpec is a similar concept to PostScript but for describing 3D scenes rather than 2D page layouts. Thus, modelling programs which understand the RenderMan Interface protocol can send data to rendering software which implements the RenderMan Interface, without caring what rendering algorithms are utilized by the latter; the interface was first published in 1988 and was designed to be sufficiently future proof to encompass advances in technology for a significant number of years. The current revision is 3.2.1, released in November 2005. What set the RISpec apart from other standards of the time was that it allowed using high-level geometric primitives, like quadrics or bicubic patches, to specify geometric primitives implicitly, rather than relying on a modeling application to generate polygons approximating these shapes explicitly beforehand.

Another novelty introduced by the RISpec at the time was the specification of a shading language. The RenderMan shading language allows material definitions of surfaces to be described not only by adjusting a small set of parameters, but in an arbitrarily complex fashion by using a C-like programming language to write shading procedures known as procedural textures and shaders. Lighting, displacements on the surface, are programmable using the shading language; the shading language allows each statement to be executed in a SIMD manner, but does not insist on it. Another feature that sets renderers based on the RISpec apart from many other renderers is the ability to output arbitrary variables as an image: surface normals, separate lighting passes and pretty much anything else can be output from the renderer in a single pass. RenderMan has much in common with OpenGL, despite the two APIs being targeted to different sets of users. Both APIs take the form of a stack-based state machine with immediate rendering of geometric primitives.

It is possible to implement either API in terms of the other. For a renderer to call itself "RenderMan-compliant", it must implement at least the following capabilities: A complete hierarchical graphics state, including the attribute and transformation stacks and the active light list. Orthographic and perspective viewing transformations. Depth-based hidden-surface elimination. Pixel filtering and spatial anti-aliasing. Gamma correction and dithering before quantization. Output of images containing any combination of RGB, A, Z; the resolutions of these files must be as specified by the user. All of the geometric primitives described in the specification, provide all of the standard primitive variables applicable to each primitive; the ability to perform shading calculations through user-programmable shading The ability to index texture maps, environment maps, shadow depth maps The fifteen standard light source, volume and imager shaders required by the specification. Any additional shaders, any deviations from the standard shaders presented in this specification, must be documented by providing the equivalent shader expressed in the RenderMan shading language.

Additionally, the renderer may implement any of the following optional capabilities: Area light sources Depth of field Displacement mapping Environment mapping Global illumination Level of detail Motion blur Special camera projections Spectral colors Ray tracing Solid modeling Volume shading For 3D Studio Max: 3Delight for 3ds Max by DNA Research For Blender: Mosaic For Houdini: built-in support. However, all third party renderer support is disabled when using Apprentice or Apprentice HD licensing options. For Lightwave: LightMan by Tim Dapper Light-R by Felipe Esquivel For Maya: 3Delight for Maya Liquid MayaMan by AnimalLogic RenderMan for Maya by Pixar For Softimage: 3Delight for Softimage Affogato by Rising Sun Pictures XSIMan by Graphic Primitives RenderMan Studio RIBKit RIBShrink and RIBDepends ShaderMan. Next Python Computer Graphics Kit for Python RubyMan for Ruby G&RT for Lua RiGO for Go Apodaca, Anthony A.. Advanced RenderMan: Creating CGI for Motion Pictures. San Francisco: Morgan Kaufmann Publishers.

ISBN 1-55860-618-1. OCLC 42621055. Ebert, David S.. Texturing and modeling: a procedural approach, 3rd ed. Burlington, MA: Morgan Kaufmann Publishers. ISBN 1-55860-848-6. OCLC 52689816. Raghavachary, Saty. Rendering for Beginners: Image synthesis using RenderMan. Burlington, MA: Focal Press. ISBN 0-240-51935-3. OCLC 57670361. Stephenson, Ian. Essential RenderMan Fast. London, New York: Springer. ISBN 1-85233-608-0. OCLC 50494960. Upstill, Steve; the RenderMan Companion: A Programmer's Guide to Realistic Computer Graphics. Reading, Mass: Addison-Wesley. ISBN 0-201-50868-0. OCLC 19741379. Cortes, Rudy; the RenderMan Shading Language Guide. Course Technology PTR. ISBN 1-59863-286-8. Reyes ren

Provenance Markup Language

The Provenance Markup Language is an interlingua for representing and sharing knowledge about how information published on the Web was asserted from information sources and/or derived from Web information by intelligent agents. The language was developed in support of DARPA Agent Markup Language with a goal of explaining how automated theorem provers derive conclusions from a set of axioms. Information, inference steps, inference rules, agents are the three main building blocks of the language. In the context of an inference step, information can play the role of conclusion. Information can play the role of axiom, a conclusion with no antecedents. PML uses the broad philosophical definition of agent as opposed to any other more specific definition of agent; the use of PML in subsequent projects evolved the language in new directions broadening its capability to represent provenance knowledge beyond the realm of ATPs and automated reasoning. The original set of requirements were relaxed to include the following: information represented as logical sentences in the Knowledge Interchange Format were allowed to be information written in any language including the English language.

These relaxations were essential to explain how knowledge is extracted from text through the use of information extraction components. Enhancements were required to further understand motivation behind the need of automated theorem provers to derive conclusions: new capabilities were added to annotate how information playing the role of axioms were attributes as assertions from information sources; the first version of PML was developed at Stanford University's Knowledge Systems Laboratory in 2003 and was co-authored by Paulo Pinheiro, Deborah McGuinness, Richard Fikes. The second version of PML developed in 2007 modularized PML1 into three modules to reduce maintenance and reuse cost: provenance and trust relations. A new version of PML based on World Wide Web Consortium's PROV is under development. Http://inference-web.org http://www.w3.org/TR/prov-overview/