More footnotes date April 2009 Beliefpropagation is a Message passing method message passing algorithm .... Beliefpropagation is commonly used in artificial intelligence and information theory and has demonstrated ... 10 sup 29 sup possible values. By exploiting the Graph mathematics graphical structure, beliefpropagation ... Beliefpropagation operates on a factor graph a bipartite graph containing nodes corresponding ... graph mathematics graph s. The algorithm is then sometimes called loopy beliefpropagation, because ... to the diameter of the tree. The precise conditions under which loopy beliefpropagation will converge ... of loopy beliefpropagation to a unique fixed point exist. ref Cite journal last1 Mooij ... an approximate visualisation of the progress of beliefpropagation and an approximate test for convergence ... is called the junction tree algorithm , which is simply beliefpropagation on a modified graph guaranteed ... x g mathbf x . math An algorithm that solves this problem is nearly identical to beliefpropagation .... Similarly, it can be shown that a fixed point of the iterative beliefpropagation algorithm in graphs with cycles is a stationary point of a free energy approximation. Generalized beliefpropagation GBP Beliefpropagation algorithms are normally presented as messages update equations on a factor .... Considering messages between regions in a graph is one way of generalizing the beliefpropagation ... as Kikuchi s cluster variation method . Improvements in the performance of beliefpropagation algorithms ... and the survey propagation algorithms are two different improvements to beliefpropagation. The name .... Gaussian beliefpropagation GaBP Gaussian beliefpropagation is a variant of the belief ... last1 Weiss first1 Yair last2 Freeman first2 William T. title Correctness of BeliefPropagation ... sums and beliefpropagation in Gaussian graphical models journal Journal of Machine Learning Research ... Bickson Gaussian beliefpropagation solver for systems of linear equations. By O. Shental, D. Bickson ... more details
wiktionarypar propagationPropagation can refer to Reproduction , and other forms of multiplication or increase Plant propagation , the production of more plants by seeds, cuttings, grafting or other methods Propagation of schema , in artificial reproduction Wave propagation , the motion of waves or the transfer of energy by wave action Radio propagation , the application of wave propagation to radio communications Software propagation , the distribution of free software in a manner explicitly permitted under the applicable license Propaganda disambig de Propagation fr Propagation nl Propagatie pl Propagacja zh ... more details
About the general concept other uses Belief disambiguation Certainty sidebar Belief is the psychological ... Schwitzgebel first Eric editor last Zalta editor first Edward contribution Belief title The Stanford ... url http plato.stanford.edu entries belief accessdate 2008 09 19 ref Belief, knowledge and epistemology The terms belief and knowledge are used differently in philosophy. Epistemology is the philosophical study of knowledge and belief. The primary problem in epistemology is to understand exactly what ... dialogue Theaetetus , philosophy has traditionally defined knowledge as justified true belief . The relationship between belief and knowledge is that a belief is knowledge if the belief is true , and if the believer ... for believing it is true. A false belief is not considered to be knowledge, even if it is sincere ..., for instance Edmund Gettier Gettier 1963 ref Gettier, EL 1963, Is justified true belief knowledge ..., pp. 357 372 ref have questioned the justified true belief definition. Belief as a psychological theory Mainstream psychology and related disciplines have traditionally treated belief as if it were the simplest ... of the belief concept stems from philosophical analysis. The concept of belief presumes a subject the believer and an object of belief the proposition . So, like other propositional attitude s, belief implies the existence of mental state s and intentionality , both of which are hotly debated ... belief s that may be ascribed to someone who has not thought about the issue . For example ..., H.D. 2006 A Cognitive Neuroscience of Belief. In Peter W. Halligan & Mansel Aylward eds. The Power of Belief Psychological Influence on Illness, Disability, and Medicine . Oxford Oxford University Press. ISBN 0 19 853010 2 ref That a belief is a mental state has been seen, by some, as contentious ... that underlies our common use of the belief concept and that it is therefore obsolete and should ... of belief. If the concept of belief is incoherent or ultimately indefensible then any attempt to find ... more details
Propagation delay is a technical term that can have a different meaning depending on the context. It can ... taken for the quantity of interest to reach its destination. Networking In computer network s, propagation ... to the receiver over a medium. It can be computed as the ratio between the link length and the propagation speed over the specific medium. Propagation delay is equal to d s where d is the distance and s is the wave propagation speed . In wireless communication, s c , i.e. the speed of light . In copper wire , the speed s generally ranges from .59c to .77c. ref name Ethernet propagation delay cite web url http stason.org TULARC networking lans ethernet 3 11 What is propagation delay Ethernet Physical Layer.html title What is propagation delay? Ethernet Physical Layer accessdate 2010 11 09 date 2010 10 21 work Ethernet FAQ ref ref name Propagation Delay cite web url http www.wildpackets.com resources compendium ethernet propagation delay title Propagation Delay and Its Relationship to Maximum .... Electronics File Full Adder Propagation Delay.svg thumb 400px A full adder has an overall gate delay ... , digital circuit s and digital electronics , the propagation delay , or gate delay , is the length ... in propagation delays of logic elements is the major contributor to glitch es in asynchronous circuit s as a result of race condition s. The principle of logical effort utilizes propagation delays to compare designs implementing the same logical statement. Propagation delay increases .... The latter is the largest contributor to the increase of propagation delay. If the output of a logic gate is connected to a long trace or used to drive many other gates high fanout the propagation delay increases substantially. Wires have an approximate propagation delay of 1 ns for every 6 in of length ... Logic gates can have propagation delays ranging from more than 10 ns down to the picosecond range ... in the electromagnetism field, the propagation delay is the length of time it takes for a signal ... more details
Chain propagation is a process in which a reactive intermediate is continuously regenerated during the course of a chemical reaction . In polymerization reaction, the reactive end group s of a polymer chain react in each propagation step with a new monomer molecule transferring the reactive group to that last unit. External links IUPAC Gold Book definition http www.iupac.org goldbook C00960.pdf Link Category Polymer chemistry physical chemistry stub et Ahela levik nl Propagatie scheikunde ... more details
In nonlinear optics , filament propagation is propagation of a beam of light through a medium without diffraction . This is possible because the Kerr effect causes an index of refraction change in the medium, resulting in self focusing of the beam. Filament propagation of laser pulses in the atmosphere was observed in 1994 by G rard Mourou and his team at University of Michigan . The balance between the self focusing refraction and self attenuating diffraction by ionization and rarefaction of a laser beam of terawatt intensities, created by chirped pulse amplification , in the atmosphere creates filaments which act as waveguides for the beam thus preventing divergence. If a light filament drops below the intensity needed for this dynamic balance, called modulation instability, it can merge with another filament and continue propagating without broadening as with all earlier means of sending light. The filaments, having made a plasma, turn the narrowband laser pulse into a broadband pulse having a wholly new set of applications. Filament propagation in a semiconductor medium can also be observed in large aperture vertical cavity surface emitting laser s. External links http www.aip.org pt vol 54 iss 8 p17.html Experiments Detail How Powerful Ultrashort Laser Pulses Propagate through Air http www.nrl.navy.mil content.php?P 03REVIEW59 Filamentation and Propagation of Ultra Short, Intense Laser Pulses in Air optics stub Category Nonlinear optics ... more details
and cuttings are one of the most effective way of propagation. Asexual propagation Plants have a number ... vegetative propagation methods almost always produce plants that are identical to the parent. Vegetative ..., propagation via asexual seeds or apomixis is asexual reproduction but not vegetative propagation ... environment Techniques for vegetative propagation include Air or ground layering Division horticulture Division Grafting and Budding Plant multiplication bud grafting , widely used in fruit tree propagation ... lighting over the top of it, usually. Seed propagation mat An electric seed propagation mat is a heated ... colony Fruit tree propagation Orthodox seed Recalcitrant seed Selection methods in plant breeding ... prop.htm Ohio State University Extension Plant propagation http grow.ars informatica.ca Grow Em Plant Propagation Database DEFAULTSORT Plant Propagation Category Plant reproduction Category Horticultural ... eo Plantopropagado ja simple Plant propagation ta ... more details
more footnotes date December 2011 Radio propagation is the behavior of radio wave s when they are transmitted , or wave propagation propagated from one point on the Earth to another, or into various parts ..., Basic Electromagnetic Theory , McGraw Hill, New York 1969 ISBN 0 048470 8, Chapter 8 ref Radio propagation ... atmosphere , due to the Sun . Understanding the effects of varying conditions on radio propagation ... , to operation of radar systems. Radio propagation is also affected by several other factors determined by its path from point to point. This path can be a direct Line of sight propagation line of sight ... approximately 60 and 600 km. ref Radiowave propagation, edited by M.Hall and L.Barclay, page ... radio signal propagation can include Sporadic E propagation sporadic E , spread F, solar flare s, geomagnetic ... and vertical electric field. ref Radiowave propagation, edited by M.Hall and L.Barclay, published ... regions of the atmosphere makes radio propagation more complex to predict and analyze than in free space. Ionospheric radio propagation has a strong connection to space weather . A sudden ... propagation and affect Global Positioning System GPS accuracy. citation needed date May 2011 Predictions of the average propagation conditions were needed and made during the Second world war . A most ... Navy . citation needed date May 2011 Since radio propagation is not fully predictable, such services ... of a given area. Free space propagation In free space , all electromagnetic wave s radio, light, X ... and magnetic field strengths. Thus, doubling the propagation path distance from the transmitter ... big Radio frequencies and their primary mode of propagation big colspan 2 style background f0f0f0 Band style background f0f0f0 Frequency style background f0f0f0 Wavelength style background f0f0f0 Propagation ... MHz 100 10 m E layer ionospheric refraction. F1, F2 propagation F2 layer ionospheric refraction. Very high frequency VHF Very High Frequency 30 300 megahertz MHz 10 1 m Sporadic E propagation Infrequent ... more details
In compiler theory , copy propagation is the process of replacing the occurrences of targets of direct assignments with their values ref name dragonbook cite book title Compilers, Principles, Techniques, & Tools Second edition first1 Alfred V. last1 Aho first2 Monica S. last2 Lam first3 Ravi last3 Sethi first4 Jeffrey D. last4 Ullman isbn 0 321 48681 1 ref . A direct assignment is an instruction of the form code x y code , which simply assigns the value of code y code to code x code . From the following code y x z 3 y Copy propagation would yield z 3 x Copy propagation often makes use of reaching definitions , use def chains and def use chains when computing which occurrences of the target may be safely replaced. If all upwards exposed uses of the target may be safely modified, the assignment operation may be eliminated. Copy propagation is a useful clean up optimization frequently used after other optimizations have already been run. Some optimizations such as elimination of common sub expressions ref name dragonbook require that copy propagation be run afterwards in order to achieve an increase in efficiency. References Reflist Further reading Muchnick, Steven S. Advanced Compiler Design and Implementation . Morgan Kaufmann. 1997. Category Compiler optimizations it Copy propagation vi Lan truy n sao ch p ... more details
Wave propagation is any of the ways in which wave physics wave s travel. With respect to the direction of the oscillation relative to the propagation direction, we can distinguish between longitudinal wave and transverse wave s. For electromagnetic wave s, propagation may occur in a vacuum as well as in a material medium. Most other wave types cannot propagate through vacuum and need a transmission medium to exist. Another useful parameter for describing the propagation is the wave velocity that mostly depends on some kind of density of the medium. Wave velocity see phase velocity group velocity signal velocity Image Seismic wave prop mine.gif thumb 400px right Seismic wave propagation in 2D modelled using FDTD method in the presence of a landmine Wave velocity is a general concept, of various kinds of wave velocities, for a wave s phase waves phase and speed concerning energy and information propagation. The phase velocity is given as math v p frac omega k , math where v sub p sub is the phase velocity in meter per second , m s , is the angular frequency in radian s per second, rad s , k is the wavenumber in radians per meter, rad m . The phase speed gives you the speed at which a point of constant phase waves phase of the wave will travel for a discrete frequency. The angular frequency cannot be chosen independently from the wavenumber k , but both are related through the dispersion relation ship math omega Omega k . , math In the special case nowrap k ck , with c a constant, the waves are called non dispersive, since all frequencies travel at the same phase speed c ... Huygens Fresnel principle Photon Polarization waves Radio propagation Reflection physics Refraction ... wave propagation at Katholieke Universiteit Leuven http math.ucr.edu jdp Relativity EM Propagation.html ... feschools waves propagation.htm Propagation of sound waves Category Wave mechanics af Radiogolfvoortplanting de Ausbreitung Physik es Propagaci n de ondas fa fr Propagation des ondes ... more details
Unit propagation UP or the one literal rule OLR is a Algorithm procedure of automated theorem proving ... set of clauses can be simplified by unit propagation because it contains the unit clause math ... of unit propagation can be summarized as follows. border 0 align center cellpadding 5 style ... to the above one. The new unit clause math c math that results from unit propagation can be used for a further application of unit propagation, which would transform math neg c vee d math into math d math . Unit propagation and resolution The second rule of unit propagation can be seen as a restricted ... clause. As for resolution, unit propagation is a correct inference rule, in that it never produces a new clause that was not entailed by the old ones. The difference between unit propagation and resolution are resolution is a complete refutation procedure while unit propagation is not in other words, even if a set of clause is contradictory, unit propagation may not generate an inconsistency ... to the set on the contrary, the non unit clause involved in a unit propagation can be removed when ... in unit propagation. Resolution calculi that include subsumption can model rule one by subsumption and rule two by a unit resolution step, followed by subsumption. Unit propagation, applied repeatedly ... on the application . In this case, unit propagation is performed based on the literals of the partial ... of the literals in the partial model. Complexity The direct implementation of unit propagation .... Unit propagation can however be done in linear time by storing, for each variable, the list ... propagation of a literal can be performed efficiently by scanning only the list of clauses containing the variable of the literal. More precisely, the total running time for doing unit propagation for all ... for unit propagation. In em Proceedings of the Fourth International Symposium on Artificial Intelligence and Mathematics em . DEFAULTSORT Unit Propagation Category Automated theorem proving nl One ... more details
merge to Schema genetic algorithms date December 2011 Dicdef In evolutionary computing such as genetic algorithms and genetic programming , propagation refers to the inheritance of characteristics of one generation by the next. For example, a Schema genetic algorithms schema is propagated if individuals in the current generation match it and so do those in the next generation. Those in the next generation may be but don t have to be children of parents who matched it. References Cite web title Foundation of Genetic Programming url http www.cs.ucl.ac.uk staff W.Langdon FOGP 2002 Cite web title Schema Propagation in Evolution Programs url http www.ubka.uni karlsruhe.de vvv 2005 wiwi 4 4.pdf 2006 Category Evolutionary computation Category Computing terminology Comp sci stub Soft eng stub ... more details
Orphan date February 2009 Software propagation is a general term for the copying & duplication of software , and was explicitly defined in version 3 of the GNU General Public License . The term is deliberately intended to distinguish between the activities permitted by free software license s and those that are forbidden by various systems of copyright . Defined by GNU GPL v3 To propagate a work means to do anything with it that, without permission, would make you directly or secondarily liable for infringement under applicable copyright law, except executing it on a computer or modifying a private copy. Propagation includes copying, distribution with or without modification , making available to the public, and in some countries other activities as well. See also Copyright External links http www.ifso.ie documents gplv3 launch 2006 01 16.html em section0 Transcript of Opening session of first international GPLv3 conference, January 16th 2006 Category Software distribution Category Free software culture and documents ... more details
Expectation propagation EP is a technique in Bayesian machine learning , developed by Thomas Minka . EP finds approximations to a probability distribution . It uses an iterative approach that leverages the factorization structure of the target distribution. It differs from other Bayesian approximation approaches such as Variational Bayesian methods . Reference Minka, T. 2001 Expectation Propagation for Approximate Bayesian Inference http research.microsoft.com en us um people minka papers ep minka ep uai.pdf Corrected pdf In Jack S. Breese, Daphne Koller Eds. UAI 01 Proceedings of the 17th Conference in Uncertainty in Artificial Intelligence, University of Washington, Seattle, Washington, USA, August 2 5, 2001. pages 362&ndash 369 External links http research.microsoft.com minka papers ep Minka s EP papers http research.microsoft.com en us um people minka papers ep roadmap.html List of papers using EP . Category Machine learning Category Bayesian statistics compsci stub ... more details
Infobox Album See Wikipedia WikiProject Albums Name Propagation Type studio Longtype Artist Robert Rich musician Robert Rich Cover Propagation album cover.jpg Released 1994 Recorded 1993 at Soundscape Studio in Mountain View, California Genre Ambient music Ambient Length 57 20 Label Hearts of Space Records Producer Robert Rich musician Robert Rich Reviews Allmusic Rating 2.5 5 Allmusic class album id r196969 pure url yes link Piero Scaruffi 6 10 http www.scaruffi.com avant rich.html link Last album Soma Steve Roach & Robert Rich album Soma br 1992 This album Propagation br 1994 Next album Trances Drones br 1994 Propagation 1994 is an album by the United States American Ambient music ambient musician Robert Rich musician Robert Rich . This album is an expression of Rich s interest in biology and is a tribute to the proliferation of organic life in all its forms. It features a complex range of world music influences, Just intonation just tunings and guest performers, similar to Rainforest album Rainforest 1989 . Track listing Animus 9 29 Lifeblood 5 31 Whispers of Eden 7 35 Terraced Fields 4 24 Luminous Horizon 9 45 Spirit Catcher 9 25 Guilin 11 11 Personnel Robert Rich Wavestation , Morpheus, E MU Proteus 3 , Yamaha DX7 DX711D , Ensoniq EPS EPS16 , Prophet 5, bamboo and PVC flutes, ocarina s, lap steel guitar , fretless bass , su gzeng, zither , brass and clay dumbek s, Tar drum tar , udu , talking drum s, kendang , Waterphone , windwand and whirlies, key tree, Woodstock chimes, rainstick , shakers, glurp Andy Wiskes environmental source recordings glurp food Lisa Moskow sarod track 3 Forrest Fang violin track 7 Carter Scholz gend r and gambang track 7 External links http www.valley entertainment.com propagation 1.html Hearts of Space Records Album Page Category Robert Rich albums Category 1994 albums Category Hearts of Space Records albums ... more details
Anomalous propagation includes different forms of electromagnetic EM wave propagation that are not encountered in a standard atmosphere. While technically the term includes propagation with larger losses than in standard atmosphere, in practical applications it is most often meant to refer to cases when signal propagates beyond normal radio horizon. Causes Air temperature profile File Superrefraction fr.jpg thumb Super r fraction in radar operation The first assumption is that an electromagnetic wave is moving through air that cools down at a standard rate with height in the troposphere . Any variation to this stratification of temperatures will modify the path followed by the wave. This can be separated into super and under refraction ref name Patterson W.L.Patterson, C.P.Hattan, G.E.Lindem, R.A.Paulus, H.V.Hitney, K.D.Anderson, A.E.Barrios. Technical Document 2648. Engineer s Refractive Effects Prediction System EREPS Version 3.0. May 1994. San Diego, CA ref Super refraction It is very common to have temperature inversion s forming near the ground, for instance air cooling at night ... the intended receiver. Other causes Other ways anomalous propagation is recorded is by troposcatter ... Patterson Finally, multipath propagation near the Earth s surface has multiple causes, including ... objects such as mountains and buildings. In Radio Anomalous propagation can be a limiting factor for the propagation of radiowaves, especially the super refraction. However, reflection on the ionosphere ... atmosphere can vary greatly from the norm. Anomalous Propagation AP refers to false radar echoes usually ... thunderstorm s cold pool. Since precipitation exists in those circumstances, the abnormal propagation ... to separate. Anomalous Propagation is different from ground Clutter radar clutter , ocean reflections ... s. See also Wave propagation Notes reflist DEFAULTSORT Anomalous Propagation Category Radio frequency propagation Category Radar signal processing Category Weather radars ... more details
Image with unknown copyright status removed Image rectilinear propagation.jpg thumb 250px Light travels in straight lines. Rectilinear propagation is a wave property which states that waves wikt propagate propagate move or spread out in straight lines. This property applies to both transverse wave transverse and longitudinal wave longitudinal waves. Even though a wave front may be bent the Surface wave waves created by a rock hitting a pond the individual waves are moving in straight lines. In the sense of the scattering of waves by an inhomogeneous medium, this situation corresponds to the case math n 1 math , where math n math is the index of the material. Category Waves physics stub ... more details
About the electromagnetic propagation phenomenon the computing storage term Multipath I O the routing term Multipath Routing nofootnotes date November 2009 In wireless telecommunication s, multipath is the radio propagationpropagation phenomenon that results in radio signalling telecommunications signals reaching the receiving antenna electronics antenna by two or more paths. Causes of multipath include atmospheric ducting , ionospheric reflection and refraction , and reflection physics reflection from water bodies and terrestrial objects such as mountains and buildings. The effects of multipath include constructive and destructive Interference wave propagation interference , and phase waves phase shifting of the signal. Destructive interference causes fading. Where the magnitudes of the signals arriving by the various paths have a distribution known as the Rayleigh distribution , this is known as Rayleigh fading . Where one component often, but not necessarily, a line of sight telecommunications line of sight component dominates, a Rice distribution Rician distribution provides a more accurate model, and this is known as Rician fading . In fax facsimile and television transmission telecommunications transmission , multipath causes jitter and ghosting television ghosting , seen as a faded ... picking up two signals separated by a delay. File Multipath propagation diagram en.svg ... is hidden, but it still degrades the displayed accuracy. Multipath propagation in wired media Multipath propagation may also happen in wired media, especially in cases in which impedance mismatches cause ... interference that multipath propagation would cause. The ITU T G.hn standard provides ... with a cyclic prefix to avoid ISI. Because multipath propagation behaves differently in each kind of wire ... and propagation losses , e.g. 99 . Keeping our aim at linear, time invariant systems, we can also ... engineering Category Radio frequency propagation ar de Mehrwegempfang es Propagaci n Multicamino ... more details
In database systems, a propagation constraint details what should happen to a related table when we update a row or rows of a target table Paul Beynon Davies, 2004, p.108 . Tables are linked using primary key to foreign key relationships. It is possible for users to update one table in a relationship in such a way that the relationship is no longer consistent and this is known as breaking referential integrity . An example of breaking referential integrity if a table of employees includes a department number for Housewares which is a foreign key to a table of departments and a user deletes that department from the department table then Housewares employees records would refer to a non existent department number. Propagation constraints are methods used by relational database management system s RDBMS to solve this problem by ensuring that relationships between tables are preserved without error. In his database textbook, Beynon Davies explains the three ways that RDBMS handle deletions of target and related tuple s Restricted Delete the user cannot delete the target row until all rows that point to it via foreign key s have been deleted. This means that all Housewares employees would need to be deleted, or their departments changed, before removing the department from the departmental table. Cascades Delete can delete the target row and all rows that point to it via foreign keys are also deleted. The process is the same as a restricted delete, except that the RDBMS would delete the Houseware employees automatically before removing the department. Nullifies Delete can delete the target row and all foreign keys pointing to it are set to Null SQL null . In this case, after removing the housewares department, employees who worked in this department would have a Null SQL NULL unknown value for their department. Bibliography Beynon Davies, P. 2004 Database Systems Third Edition, Palgrave . Category Relational database management systems ... more details
In statistics , propagation of error or propagation of uncertainty is the effect of Variable mathematics variables uncertainty uncertainties or Errors and residuals in statistics errors on the uncertainty of a function mathematics function based on them. When the variables are the values of experimental measurements they have Observational error uncertainties due to measurement limitations e.g., instrument Accuracy and precision precision which propagate to the combination of variables in the function. The uncertainty is usually defined by the absolute error . Uncertainties can also be defined by the relative error x x , which is usually written as a percentage. Most commonly the error on a quantity, x , is given as the standard deviation , . Standard deviation is the positive square root of variance , sup 2 sup . The value of a quantity and its error are often expressed as nowrap ... A j ell Sigma f mathbf A Sigma x mathbf A top math . This is the most general expression for the propagation ... to the error on f . Therefore, the propagation of error follows the linear case, above, but replacing ... Propagation accessdate 2007 04 20 author Vern Lindberg authorlink http people.rit.edu vwlsps date ... calculate the uncertainty propagation for the inverse tangent function as an example of using partial ... propagation software Interval finite element Notes references More footnotes date March 2011 References ... propagation of error material Meyer,S.L. 1975 Data Analysis for Scientists and Engineers , Wiley ... and the propagation of uncertainty explaining the benefits of using error propagation ... uphysics uncertainties Uncertainties.html Uncertainties and Error Propagation , Vern Lindberg s Guide to Uncertainties and Error Propagation. http www.bipm.org en publications guides gum.html GUM , Guide ... 98 01R3.pdf EPFL An Introduction to Error Propagation , Derivation, Meaning and Examples of Cy Fx ... de Fehlerfortpflanzung es Propagaci n de errores fr Propagation des erreurs it Propagazione degli ... more details
Main article TV and FM DX See also Tropospheric propagation The E layer of the ionosphere is not the only layer that can reflect VHF television signals. Less frequently, the higher F2 layer can also propagate VHF signals several thousand miles beyond their intended area of reception. Solar activity has a solar cycle cycle of approximately 11 years. During this period, sunspot activity rises to a peak and gradually falls again to a low level. When sunspot activity increases, the reflecting capabilities of the F1 layer surrounding earth enable high frequency short wave communications. The highest reflecting layer, the F2 layer, which is approximately 200 miles 320 km above earth, receives ultraviolet radiation from the sun , causing ionisation of the gases within this layer. During the daytime when sunspot activity is at a maximum, the F2 layer can become intensely ionized due to radiation from the sun . When solar activity is sufficiently high, the MUF Maximum Usable Frequency rises, hence the ionisation density is sufficient to reflect signals well into the 30 &ndash 50 MHz VHF spectrum. Since the MUF progressively increases, F2 reception on lower frequencies can indicate potential low band 45 55 MHz VHF TV as well as VHF amateur radio paths. A rising MUF will initially affect the 27 MHz Citizens band radio CB band, and the amateur 28 MHz 10 meters band ... single hop can reach up to approximately 3,000 miles 4,800 km . Multi hop F2 propagation has ... California when he logged a 45 MHz commercial FM station from Korea via trans Pacific F2 propagation ... F2 propagation. fact date January 2011 On January 31, 1981, Todd Emslie , Sydney, Australia, received ... Radio propagation clear channel station References references cite web title DXing FAQ work Worldwide ... FM DX RDS LogBook Software Audio broadcasting DEFAULTSORT F2 Propagation Category Radio frequency propagation th ... more details
for enhanced tropospheric propagation, in particular favouring signals which travel along the prevailing ..., enhanced tropospheric propagation may enable reception of ultra high frequency UHF TV signals ... is capable of allowing very high frequency VHF and UHF signal propagation well beyond ... ducting is a type of radio propagation that tends to happen during periods of stable, anticyclonic weather. In this propagation method, when the signal encounters a rise in temperature in the atmosphere ..., 2009 ref See also Atmospheric duct MW DX Skywave Radio propagation Tropospheric scatter Velocity of propagation Thermal fade Clear channel station Federal Standard 1037C References Reflist Refbegin ... Refend Audio broadcasting DEFAULTSORT Tropospheric Propagation Category Radio frequency propagation ... more details
wiktionary beliefBelief is a psychological state in which an individual holds a proposition or premise to be true. Belief may also refer to Religious belief , a belief regarding the supernatural, sacred, or divine Belief sociology , an element of performance, in Erving Goffman s dramaturgical sociology Belief album Belief album , an album by Nitzer Ebb Belief song Belief song , a song by John Mayer Belief , a song by Gavin DeGraw from Chariot album Chariot Belief short story Belief short story , a story by Isaac Asimov from the collection Through a Glass, Clearly See also Believe disambiguation Believer disambiguation I Believe disambiguation Faith Opinion disambig ... more details
Various Theism theistic positions can involve belief in a God or gods . They include Henotheism , worship of a single god despite recognition of other deities. Monotheism , belief in a single deity. Panentheism , belief in a deity that subsumes and transcends the universe. Pantheism , belief in a deity that is considered synonymous with the universe. Polytheism , belief in multiple deities. Category Belief ... more details
Beyond Belief may refer to In film, television and radio Beyond Belief 1990 film Beyond Belief 1990 film , a short film featuring the band Petra Beyond Belief 2007 film Beyond Belief 2007 film , a documentary about two 9 11 widows Beyond Belief 2008 film Beyond Belief 2008 film , a short film by Johnny Barker actor Johnny Barker Beyond Belief Fact or Fiction , an American TV anthology series Beyond Belief , an early 1990s TV series shown on Nickelodeon TV channel Nickelodeon , among others. Beyond Belief radio series Beyond Belief radio series , a BBC series featuring discussion of religious issues In music Beyond Belief album Beyond Belief album , an album by Petra Beyond Belief , a song by Elvis Costello from Imperial Bedroom In other uses Beyond Belief symposium , a series of conferences sponsored by the Science Network Beyond Belief Science, Religion, Reason and Survival , the first symposium, in 2006 Beyond Belief A Chronicle of Murder and its Detection , a semi fictional true crime book by Emlyn Williams Beyond Belief Islamic Excursions among the Converted Peoples , a book by V. S. Naipaul Beyond Belief , a United Kingdom UK video game publisher active from the late 80s early 90s, specializing in games for the 8 bit home computer platforms. disambig ... more details
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