Hankel matrix - Revision history

en>Anita5192: /* References */ Separated Notes and References per WP:FNNR

2015-01-02T02:21:20Z

References: Separated Notes and References per WP:FNNR

← Older revision		Revision as of 04:21, 2 January 2015
Line 1:		Line 1:
	'''Seismic tomography''' is a technique for imaging Earth’s sub-surface characteristics in an effort to understand deep geologic structure. Gathering ample compressional wave ([[P-wave]]) and shear wave ([[S-wave]]) travel time measurements allows us to compile 3D images of earth’s velocity structure.<ref>{{cite book\|last=Nolet\|first=G.\|title=Seismic Tomography \|year=1987\|publisher=Reidel Publishing Company\|pages=1–23}}</ref>		I am 37 years old and my name is Veda Taft. I life in Engelsdorf (Austria).<br><br>Feel free to visit my webpage [http://semem.ru/tag/dog%20training%20portland%20oregon/ dog training tips puppy]

	~~==Theory==~~
	Tomography is solved as an inverse problem. First measurements are made of [[seismic]] waves passing through a material. The character of these measurements is then analyzed to make inferences on the material such waves have passed through (velocity, density, etc.).<ref>{{cite web\|title=Principles of Seismic Tomography \|url=http://www.landtech.org/pdf/pdf1.pdf \|publisher=Landtech Enterprises SA\|accessdate=4 March 2012}}</ref> The velocity of p and s waves depends on the [[rheology]] of the material that they travel through ([[density]] and [[Elasticity (physics)\|elasticity]]). In short, variations in [[chemical composition]]s and thermal structure result in a change of velocity. Such waves can travel faster through relatively colder material.<ref>{{cite journal\|last=Tanimoto\|first=T\|coauthors=T. Lay\|title=Mantle dynamics and seismic tomography \|journal=PNAS \|year=2000 \|volume=97\|issue=23\|pages=12409–12410\|accessdate=4 March 2012\|bibcode = 2000PNAS...9712409T \|doi = 10.1073/pnas.210382197 \|pmid=11035784 \|pmc=34063}}</ref> It is observed that wave velocity increases with increasing depth from 2–8 km/s in the [[Crust (geology)\|crust]] up to 13 km/s in the [[Mantle (geology)\|mantle]]. Current research is based on this premise.

	~~==Process==~~
	[[Seismometers]] record ground movements in the form of seismic waves resulting from earthquakes or controlled explosions. These instruments are sensitive enough to record ground movement with a displacement 1000 times smaller than the width of a human hair (3x10<sup>−8</sup> m). A compilation of arrival times, sometimes millions of data, allows seismologists to have a clearer picture of the location and size of sub-surface structures. The result is a 3D image of a slice through the earth that serves as a seismic velocity map. The image depicts where seismic waves were able to travel faster or slower based on the differing arrive times of the waves. This in turn warrants the interpretation of the thermal structure for the deep Earth.<ref name=iris>{{cite web\|title=EarthScope Education and Outreach: Seismic Tomography\|url=http://www.iris.edu/hq/files/programs/education_and_outreach/lessons_and_resources/docs/es_tomography.pdf\|publisher=Incorporated Research Institutions for Seismology (IRIS)\|accessdate=17 January 2013}}</ref>

	~~==Methods==~~
	~~As stated above, seismic tomography is typically solved as an [[inverse problem]]. In order to estimate P-wave velocity and further simplify seismic tomography, four main methods have been devised:~~

	*Refraction traveltime tomography: Computationally simple but only reliable for making a shallow low resolution velocity structure. Within this method the observed data are the first arrival time, denoted as t: <math>t = Ls</math>. The model parameters (s) are the slowness of the waves and L is the ray path matrix.<ref>{{cite journal \|last=Taillandier \|first=C. \|coauthors=Deladerriere, N et al.\|title=First arrival traveltime tomography: when simpler is ~~better\|journal=EAGE, Vienna\|year=2011}}</ref>~~

	*Finite-frequency traveltime tomography: in an effort to obtain a higher resolution that the above method, the effects of wave diffraction are taken into account. Volumetric sensitivity kernels take the place of raypaths. Overall this allows the travel time and amplitude anomalies to be frequency-dependent, aiding the goal to increase resolution.<ref>{{cite journal\|last=Tian \|first=Yue \|coauthors=Montelli Raffaella, et al.~~\|title=Computing traveltime and amplitude sensitivity kernels~~ in ~~finite-frequency tomography \|journal=Princeton University\|year=2007\|pages=1–40}}</ref>~~

	*Reflection traveltime tomography

	*Waveform tomography : Uses seismic data to its fullest potential. Seismograms are the observed data and are controlled by the acoustic wave equation which serves as an approximation to the elastic wave propagation

	~~==Applications==~~
	~~Seismologists can use tomography to infer geologic structures such as the [[subduction]] of [[tectonic plate]]s into the warmer [[Mantle~~ (~~geology~~)\|mantle]] or the rise of a relatively hot plume body. Volcanologists use tomography to understand the scale of [[magma chamber]]s beneath [[volcano]]es. The study has also allowed for the correlation of tomographic observations with fluid dynamics models by providing a view of the internal thermal structure of the mantle.<~~ref name=iris/~~>

	[[Yellowstone]] Tomography study: Project EarthScope is currently installing 20 new seismometers every month across the US in an effort to obtain higher resolution tomographic images. This will advance our understanding of how North America has and will evolve with special attention placed on the Yellowstone hotspot associated with the [[Yellowstone supervolcano]].<~~ref name=iris/~~>

	~~==Limitations==~~
	~~Seismic tomography provides only the current velocity anomalies and all prior velocity structures are unknown. It is also difficult~~ to image slender structures due to the fact that long wavelengths are easier to recover.<ref>{{cite web\|last=Dziewonski\|first=A.M.\|title=Global seismic tomography: What we really can say and what we make up \|url=http://www.mantleplumes.org/ \|accessdate=4 March 2012\|year=2004}}</ref>

	~~==See also==~~
	* [[seismology]]
	* [[seismograph]]
	* [[EarthScope]]

	~~==References==~~
	~~{{Reflist}}~~

	~~==External Links==~~

	[http://www.iris.edu/hq/files/programs/education_and_outreach/aotm/7/SeismicTomography_Background.pdf EarthScope Education and Outreach: Seismic Tomography Background]. Incorporated Research Institutions for Seismology (IRIS). Retrieved 17 January 2013.

	[http://~~www.iris~~.~~edu/hq/programs~~/~~education_and_outreach~~/~~animations~~/~~7 Tomography Animation]. Incorporated Research Institutions for Seismology (IRIS). Retrieved 17 January 2013.~~

	~~[[Category:Fields of seismology]]~~
	~~[[Category:Geophysical imaging]]~~
	~~[[Category:Structure of the Earth]]~~
	~~[[Category:Inverse problems]~~]

en>Yobot: WP:CHECKWIKI error fixes using AWB (9075)

2013-04-08T21:39:49Z

WP:CHECKWIKI error fixes using AWB (9075)

← Older revision		Revision as of 23:39, 8 April 2013
Line 1:		Line 1:
	~~"Why does my computer keep freezing up?" I was asked by~~ a ~~great deal of people the cause of their computer freeze issues~~. ~~And I am fed up with spending much~~ time ~~inside answering the query time plus time again. This article is~~ to ~~tell we the real cause~~ of ~~your PC Freezes~~.<br><br>~~Another solution~~ is to ~~supply~~ the ~~computer program with a brand-new msvcr71 file. Often~~, ~~once the file has been corrupted or damaged~~, ~~it will no longer be able to function like it did before so it's just natural to substitute the file~~. ~~Just download another msvcr71~~.~~dll file from the~~ web. ~~Frequently, the file may come in a zip format~~. ~~Extract~~ the ~~files from~~ the ~~zip folder~~ and ~~destination them accordingly inside this location: C:\Windows\System32~~. ~~Afterward~~, ~~re-register the file~~. ~~Click Start~~ and ~~then choose Run~~. ~~When the Run window appears, sort "cmd"~~. ~~Press Enter plus then sort "regsvr32 -u msvcr71~~.~~dll" followed by "regsvr32 msvcr71~~.~~dll"~~. ~~Press Enter again and~~ the ~~file should be registered accordingly~~.<br><br>So, ~~this advanced dual scan is not just 1~~ of the ~~greater, however, it~~ is ~~very equally freeware. And as~~ of ~~all this~~ that ~~various respect CCleaner 1~~ of the ~~greater registry cleaners inside~~ the ~~marketplace now. I would add that I personally like Regcure~~ for the ~~easy reason that it has a greater interface plus I know~~ for ~~a truth it~~ is ad-~~ware without charge~~.<br><br>It is ~~usual that~~ the ~~imm32~~.~~dll error~~ is ~~caused as~~ a ~~result~~ of ~~a mis-deletion activity~~. ~~If you cannot discover~~ the ~~imm32~~.~~dll anywhere on~~ the ~~computer, there is no doubt that it should~~ be ~~mis~~-~~deleted whenever uninstalling programs or alternative unneeded files. Hence~~, ~~you are able~~ to ~~directly cope it from other programs or download it from a safe internet and then place it on a computer~~.<br><br>~~The [http~~:~~//bestregistrycleanerfix~~.~~com/tune-up-utilities tuneup utilities~~] ~~must come because standard with~~ a ~~back up and restore center~~. ~~This ought~~ to ~~be an convenient to apply process~~.~~That means which in~~ the ~~event you encounter a problem~~ with ~~your PC following using~~ a ~~registry cleaning you can just restore your settings~~.<br>~~<br>Another key element when you compare registry cleaners~~ is ~~having a facility~~ to ~~manage your start-up tasks~~. This ~~simply means~~ to ~~choose what programs you would like~~ to ~~begin when you begin~~ the PC. ~~If you have unwanted programs beginning when~~ we ~~boot~~ up ~~a PC this might cause a slow running computer~~.<br>~~<br>Why why this really is important, is because many of the 'dumb' registry products really delete these~~ files ~~without even knowing~~. ~~They simply browse by your registry plus try plus discover the most problems possible~~. ~~They then delete any files they see fit, plus because they are 'dumb', they don't really care~~. ~~This means which if they delete certain of these vital system files, they are actually going to result a LOT more damage than good~~.~~<br><br>All of these issues may be conveniently solved by the clean registry~~. ~~Installing the registry cleaner allows we to employ your PC without worries behind~~. ~~You can capable to employ we system without being afraid that it's going to crash in the middle~~. ~~Our registry cleaner will fix a host~~ of ~~errors on a PC, identifying lost, invalid or corrupt settings inside your registry.~~		'''Seismic tomography''' is a technique for imaging Earth’s sub-surface characteristics in an effort to understand deep geologic structure. Gathering ample compressional wave ([[P-wave]]) and shear wave ([[S-wave]]) travel time measurements allows us to compile 3D images of earth’s velocity structure.<ref>{{cite book\|last=Nolet\|first=G.\|title=Seismic Tomography \|year=1987\|publisher=Reidel Publishing Company\|pages=1–23}}</ref>

			==Theory==
			Tomography is solved as an inverse problem. First measurements are made of [[seismic]] waves passing through a material. The character of these measurements is then analyzed to make inferences on the material such waves have passed through (velocity, density, etc.).<ref>{{cite web\|title=Principles of Seismic Tomography \|url=http://www.landtech.org/pdf/pdf1.pdf \|publisher=Landtech Enterprises SA\|accessdate=4 March 2012}}</ref> The velocity of p and s waves depends on the [[rheology]] of the material that they travel through ([[density]] and [[Elasticity (physics)\|elasticity]]). In short, variations in [[chemical composition]]s and thermal structure result in a change of velocity. Such waves can travel faster through relatively colder material.<ref>{{cite journal\|last=Tanimoto\|first=T\|coauthors=T. Lay\|title=Mantle dynamics and seismic tomography \|journal=PNAS \|year=2000 \|volume=97\|issue=23\|pages=12409–12410\|accessdate=4 March 2012\|bibcode = 2000PNAS...9712409T \|doi = 10.1073/pnas.210382197 \|pmid=11035784 \|pmc=34063}}</ref> It is observed that wave velocity increases with increasing depth from 2–8 km/s in the [[Crust (geology)\|crust]] up to 13 km/s in the [[Mantle (geology)\|mantle]]. Current research is based on this premise.

			==Process==
			[[Seismometers]] record ground movements in the form of seismic waves resulting from earthquakes or controlled explosions. These instruments are sensitive enough to record ground movement with a displacement 1000 times smaller than the width of a human hair (3x10<sup>−8</sup> m). A compilation of arrival times, sometimes millions of data, allows seismologists to have a clearer picture of the location and size of sub-surface structures. The result is a 3D image of a slice through the earth that serves as a seismic velocity map. The image depicts where seismic waves were able to travel faster or slower based on the differing arrive times of the waves. This in turn warrants the interpretation of the thermal structure for the deep Earth.<ref name=iris>{{cite web\|title=EarthScope Education and Outreach: Seismic Tomography\|url=http://www.iris.edu/hq/files/programs/education_and_outreach/lessons_and_resources/docs/es_tomography.pdf\|publisher=Incorporated Research Institutions for Seismology (IRIS)\|accessdate=17 January 2013}}</ref>

			==Methods==
			As stated above, seismic tomography is typically solved as an [[inverse problem]]. In order to estimate P-wave velocity and further simplify seismic tomography, four main methods have been devised:

			*Refraction traveltime tomography: Computationally simple but only reliable for making a shallow low resolution velocity structure. Within this method the observed data are the first arrival time, denoted as t: <math>t = Ls</math>. The model parameters (s) are the slowness of the waves and L is the ray path matrix.<ref>{{cite journal \|last=Taillandier \|first=C. \|coauthors=Deladerriere, N et al.\|title=First arrival traveltime tomography: when simpler is better\|journal=EAGE, Vienna\|year=2011}}</ref>

			*Finite-frequency traveltime tomography: in an effort to obtain a higher resolution that the above method, the effects of wave diffraction are taken into account. Volumetric sensitivity kernels take the place of raypaths. Overall this allows the travel time and amplitude anomalies to be frequency-dependent, aiding the goal to increase resolution.<ref>{{cite journal\|last=Tian \|first=Yue \|coauthors=Montelli Raffaella, et al.\|title=Computing traveltime and amplitude sensitivity kernels in finite-frequency tomography \|journal=Princeton University\|year=2007\|pages=1–40}}</ref>

			*Reflection traveltime tomography

			*Waveform tomography : Uses seismic data to its fullest potential. Seismograms are the observed data and are controlled by the acoustic wave equation which serves as an approximation to the elastic wave propagation

			==Applications==
			Seismologists can use tomography to infer geologic structures such as the [[subduction]] of [[tectonic plate]]s into the warmer [[Mantle (geology)\|mantle]] or the rise of a relatively hot plume body. Volcanologists use tomography to understand the scale of [[magma chamber]]s beneath [[volcano]]es. The study has also allowed for the correlation of tomographic observations with fluid dynamics models by providing a view of the internal thermal structure of the mantle.<ref name=iris/>

			[[Yellowstone]] Tomography study: Project EarthScope is currently installing 20 new seismometers every month across the US in an effort to obtain higher resolution tomographic images. This will advance our understanding of how North America has and will evolve with special attention placed on the Yellowstone hotspot associated with the [[Yellowstone supervolcano]].<ref name=iris/>

			==Limitations==
			Seismic tomography provides only the current velocity anomalies and all prior velocity structures are unknown. It is also difficult to image slender structures due to the fact that long wavelengths are easier to recover.<ref>{{cite web\|last=Dziewonski\|first=A.M.\|title=Global seismic tomography: What we really can say and what we make up \|url=http://www.mantleplumes.org/ \|accessdate=4 March 2012\|year=2004}}</ref>

			==See also==
			* [[seismology]]
			* [[seismograph]]
			* [[EarthScope]]

			==References==
			{{Reflist}}

			==External Links==

			[http://www.iris.edu/hq/files/programs/education_and_outreach/aotm/7/SeismicTomography_Background.pdf EarthScope Education and Outreach: Seismic Tomography Background]. Incorporated Research Institutions for Seismology (IRIS). Retrieved 17 January 2013.

			[http://www.iris.edu/hq/programs/education_and_outreach/animations/7 Tomography Animation]. Incorporated Research Institutions for Seismology (IRIS). Retrieved 17 January 2013.

			[[Category:Fields of seismology]]
			[[Category:Geophysical imaging]]
			[[Category:Structure of the Earth]]
			[[Category:Inverse problems]]

en>Epistemenical: Hankel operator in finite-dim Gilbert space has finite dimensional matrix...

2012-08-16T21:34:34Z

Hankel operator in finite-dim Gilbert space has finite dimensional matrix...

New page

"Why does my computer keep freezing up?" I was asked by a great deal of people the cause of their computer freeze issues. And I am fed up with spending much time inside answering the query time plus time again. This article is to tell we the real cause of your PC Freezes. Another solution is to supply the computer program with a brand-new msvcr71 file. Often, once the file has been corrupted or damaged, it will no longer be able to function like it did before so it's just natural to substitute the file. Just download another msvcr71.dll file from the web. Frequently, the file may come in a zip format. Extract the files from the zip folder and destination them accordingly inside this location: C:\Windows\System32. Afterward, re-register the file. Click Start and then choose Run. When the Run window appears, sort "cmd". Press Enter plus then sort "regsvr32 -u msvcr71.dll" followed by "regsvr32 msvcr71.dll". Press Enter again and the file should be registered accordingly. So, this advanced dual scan is not just 1 of the greater, however, it is very equally freeware. And as of all this that various respect CCleaner 1 of the greater registry cleaners inside the marketplace now. I would add that I personally like Regcure for the easy reason that it has a greater interface plus I know for a truth it is ad-ware without charge. It is usual that the imm32.dll error is caused as a result of a mis-deletion activity. If you cannot discover the imm32.dll anywhere on the computer, there is no doubt that it should be mis-deleted whenever uninstalling programs or alternative unneeded files. Hence, you are able to directly cope it from other programs or download it from a safe internet and then place it on a computer. The [http://bestregistrycleanerfix.com/tune-up-utilities tuneup utilities] must come because standard with a back up and restore center. This ought to be an convenient to apply process.That means which in the event you encounter a problem with your PC following using a registry cleaning you can just restore your settings. Another key element when you compare registry cleaners is having a facility to manage your start-up tasks. This simply means to choose what programs you would like to begin when you begin the PC. If you have unwanted programs beginning when we boot up a PC this might cause a slow running computer. Why why this really is important, is because many of the 'dumb' registry products really delete these files without even knowing. They simply browse by your registry plus try plus discover the most problems possible. They then delete any files they see fit, plus because they are 'dumb', they don't really care. This means which if they delete certain of these vital system files, they are actually going to result a LOT more damage than good. All of these issues may be conveniently solved by the clean registry. Installing the registry cleaner allows we to employ your PC without worries behind. You can capable to employ we system without being afraid that it's going to crash in the middle. Our registry cleaner will fix a host of errors on a PC, identifying lost, invalid or corrupt settings inside your registry.