Models Definition and 369 Threads

I'm about to buy a refurbished laptop because there cheap, I've been using a refurbished gateway for a year no now significant problems i just want better hardware. Now one model is INTEL and one model is AMD. So if anyone wants to look at these two models and give there unbiased opinion that...

Hi, I'm interessed in using GridMathematica for parallel computing of cellular automata models. I know using mathematica so the syntax shouldn't be a problem. however, I wonder if there's here someone who has worked with it since I would like to know if the program is worth the cost etc...

Hello, I'm a computer science student in desperate need for help. In the process of writing my master's thesis I've successfully developed a traffic simulation using a model I've found in the traffic research literature, the IDM, to be precise. This model seems straight-forward and is easy to...

If one has some sort of bounce scenario for BB, with preceding contraction, then for say 1 sec or 10 sec after BB, one has a certain Hubble parameter and temperture, and associated quantum description. Then for 1 or 10 sec before the BB, would it seem most likely to have the same Hubble...

I had the pleasure of attending a lecture given by Paul Steinhardt, a Princeton professor, regarding the big bang and cyclic universe models at Fermilab this evening. Steinhardt, having written a book called The Endless Universe, is obviously a fan of the cyclic universe camp and the main focus...

M. Chodorowski argues in his http://arxiv.org/abs/astro-ph/0610590v3" that the concept of "expansion of space" is not necessary to explain the expansion of the universe, and therefore Occam's Razor tells us that we should consider discarding the concept entirely. He says that expansion is...

Has anyone in this forum worked on translating findings from invertebrates to mammals? I'm wondering how successful this tends to be. How often are actual gene sequences conserved? When the genes are conserved, how often do they have the same function across systems? Or is the most valuable...

Wen's papers purport to show that given a 3D extended lattice spin model, the emergence of light, electrons, gravitons and others should work well. How similar is what he is doing with what LQG and SF have done? How hard would it be to construct a verion of LQG/SF that reproduces all of Wen's...

Why is it that we can treat electrons as independent and non-interacting in solid state physics? What is the difference between mean-field theory and density functional theory? In lame terms please.

to those experts in the field of cosmology i was wondering if " large scale structures can be formed in stable cosmological models" or should i say that " large scale structures cannot be formed in those cosmological models that are stable with respect to gravitational or other curvature...

Does the new spinfoam models have a good semiclassical low energy large volume limit? By new I mean the new connections Rovelli have discussed as spinfoam 4d now talks to LQG.

Hello, new here, first post. Just need some help with homework. [SIZE="4"]Question One Homework Statement This norman window is made up of a semicircle and a rectangle. The total perimeter of the window is 16 cm. What is the maximum area? ** * * <<<...

I've been told that non-well-founded sets can be used to model nonstandard analysis, but I can't find any literature on the subject. Does anyone know where I can find it?

I want to post some interesting quotes about global circulation models. Well, I believe they have potential I believe that the application of the theory is often misapplied. http://www.climateaudit.org/?p=483#comment-208656 http://www.climateaudit.org/?p=483#comment-209256...

sorry to ask this stupid question... can anyone tell me exactly the difference between liquid and gas based on kinetic model? most textbooks give that in liquids inter molecular spaces are lesser than gases ,etc & etc but if compress the gas to much ,still it doesn't get converted into...

I believe, nobody knows exactly what photon is. Instead we have several MODELS of photon. Let us summarize these models. 1. Classical Physics. There is NO photon in classical physics. There reason is that there is NO QUANTIZATION of field in classical physics. However there is an...

How important is the role of integrable models in today's and future development of theories of fundamental physics? Any examples?

If we take Planck's constant to be a measure of quantum fluctuations, which seems natural in the world-view of https://www.physicsforums.com/showthread.php?t=204567", then it also seems natural to ask whether Planck's constant might vary over cosmological scales, just as temperature is a measure...

1. The problem is that I have to create a two-minute presentation on Nikola Tesla and I'm not sure what I can show that is of interest (i.e. model, etc.) I've tried making powerpoints but I have found that they aren't as interesting as models etc. Thanks

This is an announcement, in the Physics Forums context, of my "Lie fields revisited", http://arxiv.org/abs/0704.3420" , which has recently been accepted by J. Math. Phys., and an attempt to elaborate on why you might read it and to elicit critiques. For a little over ten years, I have been...

http://www.foxnews.com/story/0,2933,316734,00.html http://nostarch.com/frameset.php?startat=flego_extras Forbidden LEGO Build the Models Your Parents Warned You Against by Ulrik Pilegaard and Mike Dooley http://www.tinker.tv/downloads/forbidden_lego_gun.jpg

[SOLVED] Small-signal equivalent circuit models - How? Basically I've got an exam in circuitry this thursday and I've noticed that every single exam has one of these amplifier circuit excercises in them where the first part is usually finding the small-signal equivalent of said model and the...

Could anyone suggest a book for studying lattice models. Especially xy and Heisenberg models.

Geometric Models: E8, SO(10), Which ansatzs will prove to be right by CERN? 1. Ali H. Chamseddine and Alain Connes , SO(10) …. the spectral action associated with this noncommutative space unifies gravitation with the Standard Model at the unification scale. … Therefore the bare action we...

In the official string site, why didn't they recommend studying integrable models in the mathematics section? String theory itself is an integrable model, no?

http://www.math.columbia.edu/~woit/wordpress/ "Comment on Technicolor/Extended Technicolor Models October 26th, 2007" very brief excerpt "I would like to respond to Eric’s recent comment on Oct. 23 in which he said that “technicolor models were..eventually rejected due to some serious...

where can i find a page to get laser simulations or laser models?. thanx

I was wondering if anyone knew anything about epidemic models which take into account the ability of a disease to mutate. Basically I’m curious if there are any existing models which could predict how a rapidly changing disease might affect the progression of an epidemic, or how slower...

I am a high school physics teacher, and this year I am incorporating more history into the course, from the first class onwards. Among the topics I wish to cover are the various models of the solar system (which in early days were also models of the entire known universe.) I am looking to...

By passing warm air through a cotton sock acting as a wick immersed in water, how can I calculate the maximum evaporation to achieve the gratest temperature drop in the air flow? What is the typical formula for temperature drop in evaporative cooling models?

Not sure if this is suited for this forum or for programming... I figured more people here would have experience with SBML. Does anyone know of a good visual editor to create non linear models? I'm using Jdesigner but that only has gui support for garden variety uni-uni, uni-bi, etc...

Say I'm given a bunch of models on the same set of data how does one determine whether a valid comparison can be made between any two of them using an F Test? Is it that the estimation space of one has to be a subset of the other? Is there any easier, more practical way of determining this...

CONGRATULATIONS TO Martin Bojowald! http://arxiv.org/PS_cache/arxiv/pdf/0704/0704.1137v1.pdf Lattice refining loop quantum cosmology, anisotropic models and stability Martin Bojowald∗ 09 April 2007 Standard Theory SU(3)xSU(2)xU(1).…. String …. Have not done it. He is the first to...

For those who have been following my model, I see this as another step in the right direction. http://arxiv.org/pdf/0704.0278 q-deformed spin foam models of quantum gravity Igor Khavkine and J. Daniel Christensen 02 April 2007 Large triangulations are necessary to approximate semiclassical...

suppose our language contains one unary syombol function. we are given the next 5 models: A=<Z,x+1> B=<Z,x-1> C=<Q,-x> D=<Z,-x> E=<Q,x^2> write which of the models are isomorphic to each other. where Z is the integer set, and Q is the ratioanls set. my answer is that: A isomorphic to B...

I recently purchased a new book that reviews most historical models of the atomic nucleus: http://www.brownstationers.com/BookItem.aspx?item=9783540285694 This is the only book on this subject in the past 40+ years that gives positive review (well--any review actually) for the 1965 Linus...

The initial mass of a species of fish in a lake is 7 million tonnes. The mass of fish, if left alone, would increase at a rate proportional to the mass, with a proportionality constant of 2/year. However, commercial fishing removes fish mass at a constant rate of 15 million tonnes per year...

Hello - I am searching for some guidance, and I would greatly (greatly) appreciate any tips, pointers, etc. I am interested in the stability and geometry of nanoscale carbon structures, such as fullerenes and single-walled carbon nanotubes. I am wondering where to begin to develop - for my own...

I am not sure which distribution this is: there are N animals in a forest, we don't know N but would like to estimate it... so, I need to select a model (distribution) ps: i am trying to avoid Normal distribution...

"In these and similar ways, the progress of science has itself shown that there can be no pictorial representation of the workings of nature of a kind which would be intelligible to our limited minds. The study of physics has driven us to the positivist conception of physics. We can never...

I want to know about the application of linear viscoelastic models in polymers...??

These are some empirical excess Gibbs energy models used to calculate activity coefficients for non-ideal liquid mixtures. I didn't find many on the web, so I thought I'll put them here for future reference All x_i refer to the mole fraction of the ith species in the solution. To calculate the...

NOTE: Taken from another thread on a similar subject: https://www.physicsforums.com/showthread.php?t=125698 "An infinite amount of space with matter uniformly distributed throughout", is not a claim of infinite matter – at least it shouldn't be. If matter is assumed to be inside of a greater...

For some reason, I developed a sudden interest in eclipsing binary stars today and observational data from them. Specifically, I'm trying to understand what would be "seen" from a pair of identical sources rotating with the same constant speed on opposite sides in a common circular orbit...

Scope The MMSNF Workshops aim at stimulating research and discussions on modelling and simulations of nuclear fuels and coupling the results with fuel performance codes. The aspect of fission-product modelling (not only important for fuel performance but also with respect to safety) is...

I was just reading a very cool article called "Knit Theory" in the March issue of Discover magazine. Mathematician Daina Taimina came up with the very clever idea of representing hyperbolic geometric forms as crocheted models. The idea was born out of necessity when she went to teach a class...

Integral called my attention to a Sci Channel show about Rogue Waves called "Killer Waves". Rogue waves are now known to exist, but for about a century experts have argued that these thirty meter monsters can't exist because the linear model used by the shipping industry says that monster waves...

http://news.scotsman.com/scitech.cfm?id=16902006 what?

hi, i took calc 3 and differential equations. that was about a year ago and i vaguely remember what that's about. I'm thinking about electrical engineering and i heard from many that its math intensive. can someone tell me exactly what math is involved? i've been told to look into classes...

Anybody who can explain the details of atomic spectra by classical means will win a Nobel. Particularly, 100 years ago, quite a few have tried to build classical models of the atom, all without success. In the meantime we've put semiconductors and lasers, quantum devices both, radioactivity and...