Models Definition and 400 Threads

[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?

Homework Statement Problem: 2.6.8 Enderton: A Mathematical Introduction to Logic Assume that A is true in all infinite models of a theory T. Show that there is a finite number k such that A is true in all models D of T for which |D| has k or more elements. The Attempt at a Solution...

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...

says who? http://www.liberal-international.org/editorial.asp?ia_id=1451 http://www.globalresearch.ca/index.php?context=viewArticle&code=20070502&articleId=5543 What is the world coming to if the climate deniers call themselfs "the World Federation of Scientists"? :devil:

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...

It is possible to run any of these hurricane models on a home desktop? If so, does anyone know where I can get information on the models? Can I download the model/source code/program itself? Will I need a data feed from the national weather service?

I understand that there are a couple of statistical models out there that describe physical systems. One I know is Fermi-Dirac statistics. What are the other models, what are their key features and when are they applied? When working with a system, how can you be sure you should be using this...

On a page such as this, from Bahcall's website, you can get links to the input parameters, and the publications describing the progressive refinements to the various standard solar models. And http://www.ap.stmarys.ca/~guenther/Level01/solar/solar_history.html will give you a thumbnail...

Where I can find more about models of atom? I need a name of site for example….

SpaceTiger has created a very valuable thread on Mainstream Cosmology. For good scientific practice it is important to compare standard theories with testable alternatives, however ST's thread is not the place to do it. The theory of Self Creation Cosmology (SCC) presents itself as such a...

You all know how perfect pictures of super-models are and how they get a little tweaked before going to print. But did you know how much tweaked? http://homepage.mac.com/gapodaca/digital/bikini/index.html Pretty nasty.

Hi, I have a question regarding natural growth and logistic models. According to my textbook, any exponential equations, P(t) = e^kt can be expressed logistically as P(t) = K/(1 + Ae^-kt) where A = (K-P0)/P0. When I applied this rule to P(t) = e ^0.0015t, and P(t) = 6000 / (1 + 5e^-0.0015t) it...

Look around you. Everyday objects, linked together. How? By mathematics. Not a simple design, but a complex wonderful array of chaos models called fractals. These "fractals" are ever changing, always on the brink of a different state. Does this sound like math? Believe it or not, all of the...

The cosmological models of Lemaitre-Tolman-Bondi describe spherically symmetric universes with isotropic but inhomogeneous space, i.e. there are concentric shells with different mean mass densities. The LTB line element is: ds^2 = -dt^2 + \frac{(R'(t, r))^2}{1+2E(r) r^2}dr^2 + R^2(t...

What do you see as the best explanations for validity of non-local & gradient constitutive models (considering metal plasticity and damage)? On many occations they naturally work much better than traditional models, but I'm looking for other directly physical phenomena based information, not...

I am trying to get a basic understanding of the physics of the interstellar medium and the current models which describe it (FGH and McKee-Ostriker). A first question arises regarding the possible assumption of a gas in ionization equilibrium, in which ionizarion and recombination occur at...

I have a lab practical coming up and they use models a lot on these exams. I printed out pictures of the models with their respective keys but it's impossible tosee the numbers on a model by a picture. I was just wondering if anyone could recommend websites that have models to learn the parts of...

Ok, I'm a little lost so if this subject is off topic for this forum then I appoligize. I am working on a modeling project that I'm trying to implement some code for and I don't even know where to start. I'm not that good of a coder nor am I that great at math but this project, in part, is to...

(ok. I haven't given up with the relativity wrong thread. This is just something I'm thinking on meanwhile). Also please excuse my english as it is not my mother tounge. ok, for a moment let's forget about the wavelike properties of light (I had some ideas to explain light propagation like...

There is much confusion and mystery surrounding the Multiverse Theory. At present there is a wide range of different Multiverse Theories, which this paper does a good job in giving the basic concept behind the different variations Multiverse cosmological models

So, this doesn't fit the current model, right? http://heraldsun.news.com.au/common/story_page/0,5478,8344220%255E662,00.html Nasa: http://www.gsfc.nasa.gov/topstory/2004/0107filament.html

SDSS observations, supported by Subaru and Keck, confirmed that a massive cluster of galaxies is the gravitational lens for a quadruple-quasar image, the widest pair being separated by >14" (arc seconds). In addition, "[d]iscovering one such wide gravitational lens out of over 30,000 SDSS...

Now might be a good time to get some perspective on spin foam, if there are knowledgeable people around willing to help. Baez in some TWF mentioned a paper by Freidel/Louapre with "asymptotic 10j" in the title. It suggests a way to dispell the surprise over unexpected 10j numbers discovered by...

Here is a good paper that is quite neat makes a good case for evolving extensions to Inflation models. http://arxiv.org/PS_cache/hep-th/pdf/0307/0307179.pdf