image Bassdiffusion model.svg right The Bassdiffusionmodel was developed by Frank Bass and describes ... special cases of the Bassdiffusionmodel. The first special case occurs when q 0, when ... and other virtual communities has led to an increased use of the Bassdiffusionmodel. The Bassdiffusionmodel is used to estimate the size and growth rate of these social networks. See also Diffusion ... www.bassbasement.org BassModel Frank M. Bass Official Website DEFAULTSORT BassDiffusionModel Category ... issue 3, Part 2 of 2 pages G61 G70 doi 10.1287 mksc.14.3.G71 ref The model is widely used in forecasting , especially product forecasting and technology forecasting . Mathematically, the basic Bassdiffusion is a Riccati equation with constant coefficients. Frank Bass published his paper A new product growth model for consumer durables in 1969. ref name Bass1969 cite journal last Bass first Frank authorlink Frank Bass coauthors year 1969 month title A new product growth model for consumer durables ... Muller, Eitan and Bass, Frank year 1995 month title Diffusion of new products Empirical generalizations ... Bass adopters.svg image Bass new adopters.svg Extensions to the model Generalised Bassmodel with pricing Bass found that his model fit the data for almost all product introductions, despite a wide ... extensions of the model have been proposed, only one of these reduces to the Bassmodel under ordinary circumstances. ref name Bass2004 This model was developed in 1994 by Frank Bass, Trichy Krishnan ... in generations. Norton and Bass extended the model in 1987 for sales of products with continuous repeat ... distribution , when p 0. The Bassmodel is a special case of the Gamma shifted Gompertz distribution ... Ehrenberg Dirichlet model of repeat buying and brand choice. ref Cite journal last Uncles ... ref Prior to this, Everett Rogers published Diffusion of Innovations , a highly influential work that described the different stages of product adoption. Bass contributed some mathematical ideas ... more details
Vector version available Bassdiffusion model.svg Summary Graphic prepared by contributor Licensing GFDL migration relicense Orphan image ... more details
of the Random Walk last Weiss first G. year 1994 publisher North Holland ref model for diffusion ...about the generic concept of the time dependent random process File Diffusion.svg thumb right A diffusion ... but diffusion will still continue to occur, just that there will be no net flux . Diffusion describes ... concentration. The time dependence of the statistical distribution in space is given by the diffusion equation . The concept of diffusion is tied to that of mass transfer driven by a concentration gradient. Diffusion is invoked in the social sciences to describe the spread of ideas. Diffusion in physics Diffusion is the fact that particles move spread. In molecular diffusion , the moving molecules ... random motion. They move at random because they are cold. Diffusion is this thermal motion of all liquid and gas molecules at temperatures above absolute zero . Diffusion rate is a function of only temperature .... File diffusion center.gif thumb 350px The following image shows change in excess carriers being ... of an intrinsic semiconductor bar. Electrons have a higher diffusion constant than holes, leading ... molecules is observable under an electron microscope, small molecule diffusion can only be probed in carefully controlled experimental conditions. Under normal conditions, molecular diffusion is relevant ..., some often cited examples of diffusion are wrong If cologne is sprayed in one place, it will soon be smelled in the entire room, but a simple calculation shows that this can t be due to diffusion ..., which clearly indicates convection diffusion dominates only in perfect thermal equilibrium ... immersed in a hot liquid . This explains why the diffusion of heat was explained mathematically before the diffusion of mass. Other types of diffusion Anisotropic diffusion , also known as the Perona Malik equation, enhances high gradients Anomalous diffusion , ref cite book title Diffusion and Reactions ... ref in porous medium Atomic diffusion , in solids Eddy diffusion , in coarse grained description of turbulent ... more details
Bass Anglers Sportsman Society B.A.S.S.Bassdiffusionmodel , a mathematical marketing modelBASS ...wiktionarypar bass NOTOC Bass or Basses may refer to Bass sound , describing low frequency sound Bass fish , various freshwater and saltwater species Bass Brewery , a British brewery Music Bass clef , the musical clef used for lower sounding instruments and voices Bass note , the lowest note in a chord Bassline , an instrumental part which is in the bass range Figured bass , a kind of integer musical notation Bass voice type , a type of classical male singing voice Bass instrument , one of several instruments in the bass range Acoustic bass guitar , with a hollow body Bass clarinet a clarinet with a lower sound Bass cornett , a low pitched wind instrument Bass drum , a large drum Bass flute , an instrument one octave lower than a flute Bass guitar , with a solid body and electric pickups Bass sarrusophone , a low pitched double reed instrument Bass saxophone Bass trombone , a lower pitched trombone Bass trumpet Double bass , the largest and lowest pitched bowed string instrument Electric upright bass , the electric version of a double bass Tuba , often called the bass in the context of brass instruments Bassline house , a type of electronic dance music Drum and bass , a type of electronic dance music Miami bass , a type of hip hop music Ghettotech or Detroit Bass, a form of electronic ... g e r o m e Bass, Victoria , a town in Australia Bass, West Virginia Division of Bass , a federal electoral division in Tasmania, Australia Division of Bass state , state electoral division in Tasmania, Australia Electoral district of Bass , a state electoral division in Victoria, Australia Bass Strait , between Australia and Tasmania Bass Pyramid , an island in Bass Strait Bass Rock , wildlife sanctuary off the coast of Scotland Bass Performance Hall , a performance hall in Fort Worth, Texas People with the given name Bass Armstrong , a character from Dead or Alive Other uses BASS audio library ... more details
are Bass trial only modelBass declining trial model Fourt and Woodlock model Trial Repeat models number ... Adoption Lifecycle Technology lifecycle References Bass, F. M. 1969 . A new product growth model for consumer durables . Management Science , 15, 215 227. Bass, F. M. 1986 . The adoption of a marketing model Comments and observations . In V. Mahajan & Y. Wind Eds. , Innovation Diffusion Models ...Diffusion is the process by which a new idea or new product business product is accepted by the market . The rate of diffusion is the speed that the new idea spreads from one consumer to the next. Adoption is similar to diffusion except that it deals with the psychological processes an individual goes ... change . Theories There are several theories that purport to explain the mechanics of diffusion Two ... in time they become less expensive and are diffused to lower and lower strata The Everett Rogers Diffusion .... Crossing the Chasm model developed by Geoffrey Moore This model overlays the Everett Rogers adoption ... becomes ubiquitous. technology acceptance model Technology driven models These are particularly relevant to software diffusion. The rate of acceptance of technology is determined by factors such as ease ... right thumb 260px The Diffusion of innovation diffusion curves of many household innovations, from the Federal Reserve Bank of Dallas, 1998 According to Everett M. Rogers, the rate of diffusion is influenced ... types of diffusion rate models Penetration models use test market data to develop acceptance ... states. Stochastic models recognize that many elements of the diffusion process are unknown but explicitly incorporate probabilistic terms. See also Bassdiffusionmodel Coolhunting Diffusion anthropology Diffusion of innovations Early adopter marketing Marketing Marketing management Marketing plan ... of Their Evolution 2005 New York Penguin. Rogers, Everett M. New Product Adoption and Diffusion . Journal of Consumer Research . Volume 2 March 1976 pp. 290 301. Rogers, Everett M. Diffusion of Innovations ... more details
Jump diffusion is a stochastic process that involves jump discontinuity jumps and diffusion . It has important applications in condensed matter physics and in option pricing . In physics In crystals, atomic diffusion typically consists of jumps between vacant lattice sites. On time and length scales that average over many single jumps, the net motion of the jumping atoms can be described as regular diffusion . Jump diffusion can be studied on a microscopic scale by inelastic neutron scattering and by M bauer spectroscopy . Closed expressions for the autocorrelation function have been derived for several jump diffusion models Singwi, Sj lander 1960 full alternation between oscillatory motion and directed motion Chudley, Elliot 1961 full jumps on a lattice Sears 1966, 1967 full jump diffusion of rotational degrees of freedom Hall, Ross 1981 full jump diffusion within a restricted volume In economics and finance In option pricing , a jump diffusionmodel is a form of mixture model , mixing a jump process and a diffusion process . Jump diffusion models have been introduced by Robert C. Merton as an extension of jump model s. Due to their computational tractability, the special case of a basic affine jump diffusion is popular for some credit risk and short rate model s. Derivatives market Volatility Category Stochastic processes Category Options economics stub physics stub ... more details
Atomic diffusion is a diffusion process whereby the random thermally activated movement of atom s in a solid ... and the concentration gradient. In crystals Image Chemical surface diffusion slow.gif thumb 250px right Interstitial Atomic diffusion across a 4 coordinated lattice. Note that the atoms often block each other from moving to adjacent sites. As per Fick s law of diffusion Fick s law , the net ... . In the crystal solid state, diffusion within the crystal lattice occurs by either Interstitial defect interstitial or substitutional mechanisms and is referred to as lattice diffusion coefficient lattice diffusion . ref cite book editor first P. editor last Heitjans editor2 first J. editor2 last Karger title Diffusion in condensed matter Methods, Materials, Models edition 2nd location publisher Birkhauser year 2005 isbn 3540200436 ref In interstitial lattice diffusion, a diffusant such as C in an iron ... lattice diffusion self diffusion for example , the atom can only move by substituting place with another atom. Substitutional lattice diffusion is often contingent upon the availability of Crystallographic ... from point vacancy to point vacancy by the rapid, essentially random jumping about jump diffusion ... of crystal solid state diffusion increases with temperature. For a single atom in a defect free crystal, the movement can be described by the random walk model. In 3 dimensions it can be shown that after ... math math r sim sqrt Tt . math Diffusion in polycrystalline materials can involve short circuit diffusion ... there is more open space, thereby allowing for a lower activation energy for diffusion. Atomic diffusion in polycrystalline materials is therefore often modeled using an effective diffusion coefficient , which is a combination of lattice, and grain boundary diffusion coefficient s. In general, surface diffusion occurs much faster than grain boundary diffusion, and grain boundary diffusion occurs much faster than lattice diffusion. See also Kirkendall effect Mass diffusivity References ... more details
Eddy diffusion , eddy dispersion , or turbulence turbulent diffusion is any diffusion process by which substances are mixed in the atmosphere or in any fluid system due to eddy motion . ref IUPAC Compendium of Chemical Terminology 2nd Edition 1997 Gold Book http www.iupac.org goldbook E01889.pdf Link ref ref Science world, wolframe ref In another definition ref Glossary of Meteorology http amsglossary.allenpress.com glossary browse?s e&p 9 Link ref it is mixing that is caused by eddy fluid dynamics eddies that can vary in size from the small Kolmogorov microscales to subtropical gyre s. Because the microscopic processes responsible for atmospheric mixing are too complex to model in detail, atmospheric modelers generally treat atmospheric mixing as a macroscopic eddy diffusion process. In this approach, the diffusion rate at each pressure level is parameterized by a quantity known as the eddy diffusion coefficient , K ref Chamberlain and Hunten 1987, pp. 75 and 90 ref also sometimes called eddy diffusivity , with units of math m 2 s 1 math . References Reflist Category diffusion de Eddy Diffusion nl Eddy diffusie pt Difus o turbulenta ... more details
About spontaneous dispersion of mass a more generic treatment of diffusionDiffusion File DiffusionMicroMacro.gif thumb 250px Diffusion from a microscopic and macroscopic point of view. Initially, there are solution ... to low concentration areas, following Fick s laws. Molecular diffusion , often called simply diffusion .... Diffusion explains the net flux of molecules from a region of higher concentration to one of lower concentration, but it is important to note that diffusion also occurs when there is no concentration gradient. The result of diffusion is a gradual mixing of material. In a Phase matter phase with uniform temperature, absent external net forces acting on the particles, the diffusion process ... s of the Diffusion diffusing substance in the two compartments becomes equal. Consider two systems ... it would be of equal color to system B. Molecular diffusion is typically described mathematically using Fick s laws of diffusion . Applications Diffusion is of fundamental importance in many disciplines of physics, chemistry, and biology. Some example applications of diffusion Sintering to produce ... its properties Doping semiconductor Doping during production of semiconductor s. Significance File Diffusion 1 .png thumb 280px Schematic representation of mixing of two substances by diffusionDiffusion is part of the transport phenomena . Of mass transport mechanisms, molecular diffusion is known as a slower one. Biology In cell biology , diffusion is a main form of transport for necessary materials ... url doi id isbn ref Diffusion of water H sub 2 sub O through a partially permeable membrane is classified as osmosis . Metabolism and Respiration physiology respiration rely in part upon diffusion in addition ... this gas exchange process. Tracer, self and chemical diffusion File Diffusion self1.svg thumb 340px Self diffusion, exemplified with an isotopic tracer of radioactive isotope sup 22 sup Na File Diffusion4.svg thumb 340px Example of chemical classical, Fick s, or Fickian diffusion of sodium chloride ... more details
thumb 500px right In a diffusion flame , combustion takes place at the flame surface only, where the fuel ... likely kerosene , combined with strong convection flows due to intense heat gives a turbulent diffusion flame. In combustion , a diffusion flame is a flame in which the oxidizer combines with the fuel by diffusion . As a result, the flame speed is limited by the rate of diffusion. cn date October 2011 Diffusion flames tend to burn slower and to produce more soot than premixed flame s because there may ... to the rule. The soot typically produced in a diffusion flame becomes incandescent from the heat of the flame and lends the flame its readily identifiable orange yellow color. Diffusion flames ... for diffusion may vary somewhat. For instance, a candle uses the heat of the flame itself to vaporize .... Diffusion flames are often studied in Counter flow burner counter flow also called opposed jet burners. cn date October 2011 Their interest is due to possible application in the flamelet model for turbulent ... on their axis because of the high strain rates in the vicinity of the stagnation point. Diffusion ... front, such as in the candle seen here. This is a rare example of a diffusion flame which does not produce ... The common flame of a candle is a classic example of a diffusion flame. Its yellow color owing to the large ... Image Australia Cairns Flame.jpg A nearly turbulent diffusion flame File Fire breathing 2 Luc Viatour.jpg A turbulent diffusion flame Image Candlespace.jpg A candle in a microgravity environment. This is a rare example of a diffusion flame which does not produce much soot and does not therefore have ... process External links http microgravity.grc.nasa.gov combustion lsp lsp overview.htm Diffusion ... date October 2011 , NASA http www.andreaciani.net research.htm Diffusion and edge flames in opposed ... more details
Noref date August 2011 Numerical diffusion is a difficulty with computer simulation s of continua such as fluid s wherein the simulated medium exhibits a higher diffusivity than the true medium. This phenomenon can be particularly egregious when the system should not be diffusive at all, for example an ideal fluid acquiring some spurious viscosity in a numerical model. Explanation In Eulerian method Eulerian simulations , time and space are divided into a discrete grid and the continuous differential equation s of motion such as the Navier Stokes equation are discretization discretized into finite difference equation s. The discrete equations are in general more diffusion diffusive than the original differential equations, so that the simulated system behaves differently than the intended physical system. The amount and character of the difference depends on the system being simulated and the type of discretization that is used. Most fluid dynamics or Magnetohydrodynamics magnetohydrodynamic simulations seek to reduce numerical diffusion to the minimum possible, to achieve high fidelity but under certain circumstances diffusion is added deliberately into the system to avoid mathematical singularity singularities . For example, shock wave s in fluids and current sheet s in plasma physics plasma s are in some approximations infinitely thin this can cause difficulty for numerical codes. A simple way to avoid the difficulty is to add diffusion that smooths out the shock or current sheet. Higher order numerical methods including spectral methods tend to have less numerical diffusion than low order methods. Example As an example of numerical diffusion, consider an Eulerian simulation using an explicit time advance of a drop of green dye diffusing through water. If the water is flowing ... due to this sideways transfer. This numerical effect takes the form of an extra high diffusion rate. When numerical diffusion applies to the components of the momentum vector, it is called numerical ... more details
Gnawa Diffusion is a France French and Algeria n Gnawa music band based in Paris , France . ref http www.timesonline.co.uk tol sport related reports article668436.ece Fashion Tribes , The Times . ref The group s lead singer, Amazigh literally meaning Free Man in Berber languages Tamazight , is the son of the Algeria n writer and poet Kateb Yacine . Although there is a strong Gnawa influence, the band is noted for its mix of reggae and roots music. Gnawa Diffusion is very popular in Algeria and is also well known in many other countries including Morocco and France. The band s lyrics are in Arabic language Arabic , berber languages Tamazight , French language French and English language English . Gnawa Diffusion started their career in 1993 with the release of the album L gitime diff rence . Members of the band Amazigh Kateb vocal and gimbri Mohamed Abdenour mandolin , banjo , krakebs , choir Pierre Bonnet bass guitar bass Philippe Bonnet drums Salah Meguiba Keyboard, oriental percussion , choir Pierre Feugier guitar , choir, krakebs Abdel Aziz Maysour Amar Chaoui percussionist, choir The lead singer s lyrics are often controversial. Themes range from discussions of poverty in Algeria or corruption in government to denunciations of global military actions and perceived imperialism. Nevertheless, in spite of a strong political direction, this band also has more entrancing numbers which focus on self determination and improvement. Discography 2007 Fucking Cowboys D JAMAZ Production 2003 Souk System Warner Music Group Warner 2002 DZ Live Next Musique 1999 Bab el Oued Kingston Musisoft ref http allmusic.com album bab el oued kingston r450221 review Review , Allmusic ref 1997 Algeria Melodie 1993 L gitime diff rence References reflist External links http www.gnawa diffusion.com ... gnawa diffusion 551.php French interview. Category Algerian musical groups de Gnawa Diffusion fr Gnawa Diffusion ru Gnawa Diffusion tr Gnawa Diffusion ... more details
Thermal diffusion may refer to Uranium enrichment Thermal diffusion Thermal diffusion , an obsolete method of uranium enrichment Brownian motion at a constant non zero absolute temperature . Diffusion in a temperature gradient thermophoresis , also called thermodiffusion . See also Molecular diffusion Heat conduction i.e., diffusion of heat disambig ... more details
wiktionary diffusionDiffusion is a time dependent random process causing a spread in space. Diffusion may also refer to In physical sciences Molecular diffusion , spontaneous dispersion of mass distinct from migration, caused by an external force Conduction of heat Momentum diffusionDiffusion equation Heat equation Eddy diffusion In physical sciences, more specific or modified meanings Diffusion MRI , Diffusion acoustics , sound waves Atomic diffusion , Brownian motion Collective diffusion Facilitated diffusion Effusion of a gas through small holes Gaseous diffusion It diffusion Knudsen diffusion of particles from very small containers Osmosis Photon diffusion , an optical effect Diffuse reflection , the reflection of light from an uneven or granular surface Reverse diffusion Rotational diffusion Self diffusion Surface diffusion Thermodiffusion In the social sciences Diffusion of innovations within a society or a culture or between them Lexical diffusion within a culture Trans cultural diffusion of culture items between cultures In computer science Diffuse reflection , the reflection of light from an uneven or granular surface Diffusion cryptography , the spreading of influence of bits in a cipher Error diffusion in image processing In other areas Diffusion business , the process by which a new idea or new product is accepted by the market Diffusion process , in probability theory the solution to a stochastic differential equation Diffusion of responsibility Society for the Diffusion of Useful Knowledge Diffusion Science Radio Show , a science radio show and podcast on 2SER in Sydney Diffusion Records , an independent record label Diffusion album Diffusion album , a 2008 album by 7for4 See also Migration disambiguation Diffuse nebula disambiguation de Diffusion Begriffskl rung es Difusi n fr Diffusion it Diffusione sk Dif zia ... more details
Diffusion maps,introduced by R.R. Coifman and S. Lafon in ref name DifussionMap ref name Diffusion ,is a machine ... MDS , diffusion maps is a non linear method and focus on discovering the underlying manifold that the data is embedded. By integrating local similarities at different scales, diffusion maps gives a global description of the data set. Compared with other methods, diffusion maps is robust to noise perturbation and is computationally inexpensive. Definition of Diffusion Maps Follow by ref name Introduction , Diffusion Maps can be defined in four stps. Connectivity Diffusion maps leverages the relationship between heat diffusion and random walk Markov Chain . The basic observation is that if we take ... should be guided by the application that one has in mind. Diffusion Process With the definition of connectivity between two points, we can define the diffusion matrix math L math it s also a version ... of math t math , we observe the data set at different scales. This is the diffusion process. Diffusion ... structure of the data set have high probability. Diffusion Distance The diffusion distance at time t between ... here math w y math is a weighted function which can often treated as math w y 1 math Diffusion Process Now, we can give the definition of diffusion map as math Psi t x lambda 1 t psi 1 x , lambda 2 t psi ... the diffusion map from the original data to a k dimension space which is embedded in the original space. Algorithm The basic algorithm framework of Diffusion Map is as Step 1. Given the similarity matrix ... of math M t math Step 4. Use Diffusion Map to get the embedding matrix Y Application In the paper ref name Nadler05diffusionmaps ,they showed how to design a kernel that reproduces the diffusion ... and therefore provides a separation of the statistics and the geometry of the data. Since Diffusion ... points in the manifold the data is embedded. Based on diffusion map, there are many applications, such as spectral ... , 3D model segmentation ref name sidi11 ,sampling on manifold and so on. See also Nonlinear dimensionality ... more details
Image Surface diffusion hopping.gif thumb 288px right Figure 1. Model of a single adatom diffusing across ... display diffusion behavior that deviates from the conventional model of nearest neighbor jumps. ref Antczak, Ehrlich 2007, p.39 ref Tunneling diffusion is a particularly interesting example of an unconventional ... multiplied by the time allowed for diffusion, t . In the most basic model only nearest neighbor jumps ... Chemical surface diffusion slow.gif thumb 288px right Figure 3. Model of six adatoms diffusing across ... exchange diffusion 2.gif thumb 200px Figure 4. Model of an atomic exchange mechanism occurring between ... Figure 5. Model of surface diffusion occurring via the vacancy mechanism. When surface coverage is nearly ... is conceptually the most basic mechanism for diffusion of adatoms. In this model, the adatoms ... of clusters. 1 Sequential displacement 2 Edge diffusion 3 Evaporation condensation. In this model ... rate to nearby sites. Also, the model displays examples of both nearest neighbor jumps straight and next ... diffusion is a general process involving the motion of adatom s, molecule s, and atomic clusters ... adjacent adsorption sites on a surface, as in figure 1. Just as in bulk diffusion , this motion is typically ... tunneling effect. Various analytical tools may be used to wikt elucidate elucidate surface diffusion ... diffusion are limited to well below the melting point of the substrate materials science substrate .... ref Antczak, Ehrlich 2007, p. 50, 59 ref Surface diffusion rates and mechanisms are affected by a variety ..., p. 109 ref As such, the principles of surface diffusion are critical for the chemical industry chemical ... salts used in photographic film . ref name Shust109 Kinetics Image Diffusion energy landscape.png thumb 300px right Figure 2. Diagram of the energy landscape for diffusion in one dimension. x is displacement ... adsorption sites E sub diff sub is the barrier to diffusion. Surface diffusion kinetics can be thought ... , the potential energy barrier to diffusion. Equation 1 describes the relationship math Gamma nu e E ... more details
Multiple issues wikify December 2011 orphan December 2011 Diffusion map ,introduced by R.R. Coifman and S. Lafon in, ref name DifussionMap ref name Diffusion is a machine learning Machine learning algorithms ... Scaling MDS , diffusion map is a non linear method and focus on discovering the underlying manifold that the data is embedded. By integrating local similarities at different scales, diffusion map gives a global description of the data set. Compared with other methods, diffusion map is robust to noise perturbation and is computationally inexpensive. Definition of Diffusion Map Follow by, ref name Introduction Diffusion Map can be defined in four stps. Connectivity Diffusion map tries to find ... has in mind. Diffusion Process With the definition of connectivity between two points, we can define the diffusion matrix math L math it s also a version of graph Laplacian matrix math L i,j k x i ,x ... scales. This is the diffusion process. Diffusion process reveals the global geometric structure .... Diffusion Distance The diffusion distance at time t between two points can be measured as the similarity ... can often treated as math w y 1 math Diffusion Process Now, we can give the definition of diffusion ... the first k Eigenvalues and eigenvectors eigenvectors and eigenvalues , we get the diffusion map from ... algorithm framework of Diffusion Map is as Step 1. Given the similarity matrix L Step 2. Form ... M t math Step 4. Use Diffusion Map to get the embedding matrix Y Application In the paper, ref name Nadler05diffusionmaps they showed how to design a kernel that reproduces the diffusion induced by a Fokker ... a separation of the statistics and the geometry of the data. Since Diffusion map gives a global ... the data is embedded. Based on diffusion map, there are many applications, such as spectral clustering , low dimensional representation of images, image segmentation , ref name Farbman 3D model ... G. Kevrekidis year 2005 title Diffusion Maps, Spectral Clustering and Eigenfunctions of Fokker ... more details
and fully functional model that can be applied to the diffusion of a species in all turbulent ... Turbulent Diffusion and Gaussian Plume Model from University of Washington DEFAULTSORT Turbulent ...Orphan date April 2010 Turbulent diffusion is the transport of mass, heat, or momentum within a system ..., density gradients, and high velocities. It occurs much more rapidly than molecular diffusion and is therefore ... diffusion acts as an excellent process for quickly reducing the concentrations of a species in a fluid ... Roberts02 cite book author Roberts, P.J.W., & Webster, D.R. chapter Turbulent Diffusion editor Shen ... Atmospheric diffusion and pollutants Atmospheric dispersion, or diffusion, studies how pollutants ... both been used to simulate atmospheric diffusion, and are important for a proper understanding of how ... vertical and horizontal wind, but additionally integrate Fickian diffusion theory to account for turbulence ... in time, it is difficult to better calculate the effects of turbulent diffusion on pollutants. Fickian diffusion theory and further advancements in research on atmospheric diffusion can be applied to model the effects that current emission rates of pollutants from various sources have on the atmosphere ... ref Turbulent diffusion flames Using planar laser induced fluorescence PLIF and particle image velocimetry PIV processes, there has been on going research on the effects of turbulent diffusion in flames ... reactions in jet diffusion flames involving methane CH sub 4 sub , hydrogen H sub 2 sub and nitrogen ..., lifted jet diffusion flames journal Combustion and Flame volume 144 issue 3 pages 494 512 year 2006 .... title Experimental analysis of local flame extinction in a turbulent jet diffusion flame by high ... to turbulent diffusion focuses on an infinitesimal volume at a specific space and time in a fixed ... ref name Csanady73 cite book author Csanady, G.T. title Turbulent diffusion in the environment publisher ... Geophysics and astrophysics monographs volume 3 ref .The model is useful because Eulerian statistics ... more details
Demic diffusion is a demographic term referring to a migratory model developed by Cavalli Sforza , that consists of population diffusion into and across an area previously uninhabited by that group, possibly, but not necessarily, displacing, replacing, or intermixing with a pre existing population e.g. as has been suggested for the spread of agriculture across Neolithic Europe , and what occurred with the European colonization of the Americas . In its original formulation, the demic diffusionmodel includes three phases, namely 1 population growth, prompted by new available resources as in the case of early farmers, and or other technological developments 2 a dispersal into regions with lower population density 3 a limited initial admixture Clarify date April 2010 with the people encountered in the process. Evidence Theoretical work by Luca Cavalli Sforza showed that, if admixture between expanding farmers and previously resident groups of hunters and gatherers is not immediate, the process would result in the establishment of broad genetic gradients. Because broad gradients spanning much of Europe in the Southeast Northwest direction were identified in empirical genetic studies by Cavalli Sforza, Robert R. Sokal , Guido Barbujani , Loun s Chikhi and others, it seemed likely that the spread of agriculture into Europe occurred by the expansion and spread of agriculturists, possibly originating in the Fertile crescent of the Near East region. This is referred to as the Neolithic demic diffusionmodel. Craniometry Craniometric ref C. Loring Brace, Noriko Seguchi, Conrad B. Quintyn ... demic diffusionmodel. Proc. Nat. Acad. Sci . 99 17 11008 11013. Reflist External links http mbe.oxfordjournals.org ... cgi reprint 99 17 11008 Y genetic data support the Neolithic demic diffusionmodel, Chikhi 2002 ... 1181965 Origin, Diffusion, and Differentiation of Y Chromosome Haplogroups E and J Inferences on the Neolithization ..., Chikhi 1997. See also Cultural diffusion the spread of culture via interaction between individuals ... more details
gradient directions, sufficient to compute the diffusion tensor . The diffusionmodel is a rather simple model of the diffusion process, assuming homogeneity and linearity of the diffusion within each image voxel. From the diffusion tensor, diffusion anisotropy measures such as the fractional anisotropy FA , can be computed. Moreover, the principal direction of the diffusion tensor can be used ... is connected to which other part . Recently, more advanced models of the diffusion process have been proposed that aim to overcome the weaknesses of the diffusion tensor model. Amongst others ... each other. In the classic diffusion ellipsoid tensor model, the information from the crossing tract ...Diagnostic infobox Name Diffusion MRI Image Illus dti.gif Caption DTI Color Map ICD10 ICD9 MeshID D038524 OPS301 OtherCodes Diffusion MRI is a magnetic resonance imaging MRI method that produces in vivo ... of water diffusion , which is capable of showing connections between brain regions. ref Hagmann et al, Understanding Diffusion MR Imaging Techniques From Scalar Diffusion weighted Imaging to Diffusion ... 1 S205.full ref The field of diffusion MRI can be understood in terms of two distinct classes of application&mdash diffusion weighted MRI and diffusion tensor MRI. Diffusion MRI is a key technology in the creation ... 2010 09 introducing human connectome project first its kind map brains circuitry ref In diffusion ... a single best measurement of the rate of water diffusion at that location. This measurement is more ... movement e.g. grey matter in the cerebral cortex and major brain nuclei&mdash where the diffusion rate appears to be the same when measured along any axis. Diffusion tensor imaging DTI is important ... perpendicular to the preferred direction. This also means that the measured rate of diffusion will differ depending on the direction from which an observer is looking. Traditionally, in diffusion ... of the diffusion tensor or average diffusivity , a putative measure of edema . Clinically, trace weighted ... more details
Error diffusion is a type of halftone halftoning in which the quantization image processing quantization residual is distributed to neighboring pixel s that have not yet been processed. Its main use is to convert ... many other halftoning methods, error diffusion is classified as an area operation, because what ... , do not have these complications. Error Diffusion has the tendency to enhance edges in an image ... analog version of error diffusion. Enter the digital era Floyd Steinberg dithering Floyd and Steinberg described a system for performing error diffusion on digital images based on a simple kernel math ... & 7 & 5 & 3 1 & 3 & 5 & 3 & 1 end array right math Algorithm Description Error diffusion takes a monochrome ... diffusion involves reducing the number of quantization states to just two per channel. This makes ... is two per channel, unless otherwise stated. One dimensional error diffusion The simplest form ... pixel in the image and the process repeats. Two dimensional error diffusion One dimensional error diffusion tends to have severe image artifacts that show up as distinct vertical lines. Two dimensional error diffusion reduces the visual artifacts. The simplest algorithm is exactly like one dimensional error diffusion, except half the error is added to the next pixel, and one quarter of the error ... error diffusion. Color error diffusion The same algorithms may be applied to each of the red, green ... results may be obtained by first converting the color channels into a perceptive color model that will separate lightness, hue and saturation channels, so that a higher weight for error diffusion ... of these perceptive channels, if they don t scale linearly with the human vision, so that error diffusion ... error. Error diffusion with several gray levels Error Diffusion may also be used to produce ... to dark the error diffusion algorithm tends to make the next generated pixel be black. Dark to light ... effect at the expense of gray level reproduction accuracy. This results in error diffusion having a higher ... more details
Unreferenced stub auto yes date December 2009 Orphan date December 2009 Reverse diffusion refers to a situation where the transport of particles atom s or molecule s in a medium occurs towards regions of lower concentration gradients, opposite to that observed during diffusion . This phenomenon occurs during phase matter phase separation and is described by the Cahn Hilliard equation . Reverse diffusion also refers to when water is forced from an region of lower concentration to high. DEFAULTSORT Reverse Diffusion Category Diffusion Physics stub cs Reverzn osm za ... more details
Diffusion wavelets are a fast multiscale framework for the analysis of functions on discrete or discretized continuous structures like graphs, manifolds, and point clouds in Euclidean space. Diffusion wavelets are an extension of classical Wavelet wavelet theory from harmonic analysis . Unlike classical wavelets whose basis functions are predetermined, diffusion wavelets are adapted to the geometry of a given diffusion operator math T math e.g., a heat kernel or a random walk . Moreover, the diffusion wavelet basis functions are constructed by dilation using the dyadic powers powers of two of math T math . These dyadic powers of math T math diffusion over the space and propagate local relationships in the function throughout the space until they become global. And if the rank of higher powers of math T math decrease i.e., its spectrum decays , then these higher powers become compressible ... subspaces. Diffusion wavelets were first introduced in 2004 by Ronald Coifman and Mauro ... Diffusion Wavelets journal Applied and Computational Harmonic Analysis year 2008 month May volume ... of the diffusion operator math T math at these scales. In the algorithm below, the subscript ... ref code Input math T math is the matrix representation of the diffusion operator math J math is the maximum ... , epsilon right math math text end for math code Applications Mathematics Diffusion wavelets are of general ... s function and the inverse Laplacian matrix graph Laplacian . Computer science Diffusion wavelets have ... Function Approximation using Diffusion Wavelets and Laplacian Eigenfunctions journal Advances in Neural ..., Sridhar title Multiscale Dimensionality Reduction with Diffusion Wavelets journal Univ. of Massachusetts ... sridhar icml07.pdf ref topic model analysis of document corpora. ref cite journal last Wang first Chang coauthors Mahadevan, Sridhar title Multiscale Analysis of Document Corpora Based on Diffusion ... www.cs.umass.edu chwang dwt.html Chang Wang s diffusion wavelet page Category Wavelets ... more details
According to IUPAC definition, ref http goldbook.iupac.org S05582.html IUPAC Compendium of Chemical Terminology, 2nd edition ref self diffusion coefficient is the diffusion coefficient math D i math of species math i math when the chemical potential gradient equals zero. It is linked to the diffusion coefficient math D i math by the equation math D i D i frac partial ln c i partial ln a i . math Here, math a i math is the activity chemistry activity of the species math i math in the solution and math c i math is the concentration of math i math . This term is commonly assumed to be equal to the tracer diffusion determined by watching the movement of an Isotopic labeling isotope in the material of interest. See also Diffusion Molecular diffusion References reflist DEFAULTSORT Self Diffusion Category Diffusion physics stub pt Autodifus o ... more details
File Diffusionofideas.PNG thumb 330px The diffusion of innovations according to Rogers. With successive ... reach the saturation level. In mathematics the S curve is known as the logistic function . Diffusion ... in his 1962 book Diffusion of Innovations . He said diffusion is the process by which an innovation ... of the diffusion of innovations theory are varied and span multiple disciplines. History sociology ... on Trans cultural diffusion or Roland Burrage Dixon 1928 The Building of Cultures . ref Its ..., H. E. 1936 The Curve of Culture Diffusion Rate , American Sociological Review, 1 4 547 556. ref who provided examples of institutional diffusion such as postage stamps and compulsory school laws. In 1962 Everett Rogers , a professor of rural sociology published Diffusion of Innovations . In the book, Rogers synthesized research from over 508 diffusion studies and produced a theory for the adoption ... the spread of a new idea the innovation, communication channels, time, and a social system. That is, diffusion ... rather, subjective perceptions of the innovation influence diffusion. The process occurs over time. Finally, social systems determine diffusion, norms on diffusion, roles of opinion leaders and change agents, types of innovation decisions, and innovation consequences. To use Rogers model in health requires us to assume that the innovation in classical diffusion theory is equivalent to scientific ... Theory dead link date March 2011 ref The origins of the diffusion of innovations theory are varied and span across multiple disciplines. Rogers identifies six main traditions that impacted diffusion ... . The diffusion of innovation theory has been largely influenced by the work of rural sociologists. ref Ryan 1943 , see above. ref Elements The key elements in diffusion research are class wikitable ... decisions have been identified within diffusion of innovations. class wikitable Type Definition ... social system by few individuals in positions of influence or power. Mechanism Diffusion of an innovation ... more details
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