Parameter Definition and 392 Threads

Hi, I have an optical model, fully programmably controllable with python. I want to know how much my variables (say N) of my model impact a certain parameter (i.e power, abberations). Now I have no clue how to go about this. There must be some analytical (numerical) method that I could use but...

i would like to know the self absorption parameter of 3x3 inches NaI crystal. which is used in estim,ating the radionuclides

Hi, I have been using Semiconductor Parameter Analyzer Agilent 4156B for 1 year. Since a month it is malfuntioning. I am not getting the required IV for my Resistive Random Access Memory (RRAM) devices. To confirm, I checked my devices using some other lab's analyzer which proved that there is...

I have a PDE which is the following: $$\frac {\partial n}{\partial t} = -G\cdot\frac {\partial n}{\partial L}$$ with boundary condition: $$n(t,0,p) = \frac {B}{G}$$ , where G is a constant, L is length and t is time. G and B depend on a set of parameters, something like $$B = k_1\cdot C^a$$...

Homework Statement We have a Markov Random Field with the log likelihood as such: $$ l(\theta) = \sum\limits_{i=1}^L \log p(x^{(i)}|\theta) = \sum\limits_{i=1}^L \left( \sum\limits_{s \in V} \theta_{s} x_{s}^{(i)} - \log \sum\limits_{x} \exp \left\lbrace \sum\limits_{s \in V} \theta_{s} x_{s}...

Dear all, Considering Einstein Hilbert lagrangian, by using Einstein field equations one can get the form of Friedman equations and consequently the Hubble parameter. I know that in f(R) models, Einstein equations get modified. However, what happens to the Friedman equation and the Hubble...

For some small parameter ##\epsilon##, how would one go about making an approximation such as ##\sqrt{k^2-\epsilon^2}\approx k-\frac{\epsilon^2}{2k}##? I was thinking that these types of approximations came from truncating Taylor series expansions, but I can't see how it would be obvious which...

Hi folks. I have the following question. I have a model M containing 20 adjustable parameters k = {k_j}. I also have 40-50 measured temporal profiles e = {e_i} at my disposal. I can use M to predict the experimental values after solving complex systems of differential...

hi all... i have payment schedule with parameter like this : e.g. original price $\$$5000 - if i pay in <=6 months i have penalty (add penalty) 1% from original price - if i pay in >6 months i have penalty (add penalty) 10% from original price e.g. my problem is : i have $\$$5000 and...

Hi everyone, There is a b&h Time-Correlated Single Photon Counting (tcspc, spc-130) in our lab, and I use it for coincidence of spdc in quantum optics. Actually I know some about how it work, but when it comes to parameter setting of the software I know nothing. Recently, I read some paper...

Hi everyone I have a system of ODE as follows x1_dot=f1(t)-ax1 x2_dot=f2(t)-ax2 x3_dot=f3(t)-ax3 f1,2,3(t) are unknown nonlinear functions of time, a is constant and unknown, x1,2,3 and their derivatives are given. How can I estimate the parameter a from the given information? Thanks

I'm trying to understand a few things about the kinematics of collision processes. I guess it's because we calculate the scattered angle of the projectile and then back calculate to get a value for the impact parameter. Is this right?

Homework Statement A proton of mass m, charge +e and (asymptotic) momentum mv is incident on a Nucleus of charge +Ze at an impact parameter b. Consider only coulomb repulsion and classical mechanics, what is distance of closest approach - d? Homework Equations Haven't encountered impact...

I must have a mental block here! Given r(t) = (x(t), y(t)) = (-3t, 4t) - clearly this passes through the origin. Eliminating t results in $4x + 3y = 0 $. Normalising gives $\frac{4}{5}x + \frac{3}{5}y = 0 $ which we can write as $ \vec{n}.\vec{r}=0 $ , i.e. $ \vec{n} = \left(\frac{4}{5}...

Hi, I'm having trouble answering Question 9.20 in Hobson's book (Link: http://tinyurl.com/pjsymtd). This asks to prove that a photon will just graze the surface of a massive sphere if the impact parameter is b = r(\frac{r}{r-2\mu})^\frac{1}{2} So far I have used the geodeisic equations...

Homework Statement Given this image http://postimg.org/image/m9dyiqwy3/ find the lattice parametre of the reciprocal lattice and the coordinates of the point x. Homework Equations a*[/B]=2π(b×c)/(a⋅b×c) b*=2π(c×a)/(b⋅c×a) c*=2π(a×b)/(c⋅a×b) Which are the vectors of the reciprocal lattice a is...

I would like to know a typical W/L value for a MOSFET transistor. L = channel length W = channel width/transistor width I am currently designing L to be L = 0.0001 cm for a transistor. Cox = 5nF mobility 1155 cm^2/Vs K = 0.583 mA/V^2 This gives W = 20 cm. But this is way to large for a...

Homework Statement A pendulum with a mass of 0.1 kg was released. The string made an angle of 7 ° with the vertical. The bob of the pendulum returns to its lowest point every 0.1 seconds. What is the period, frequency? Homework Equations T= 1/f T=sec/cycles F= cycles/sec The Attempt at a...

Homework Statement Find the arclength parameter s=s(t) for the path x(t)=e^(at)cos(bt)i + e^(at)sin(bt)j + e^(at)k Homework Equations s(t)=\int_{a}^{t}\left | \mathbf{x}(\tau ) \right |d\tau The Attempt at a Solution I took the derivative and squared it, arriving at the equation (-be\sin...

I've come across two different approaches to quantifying what l is in the equation for hydraulic gradient Δh/L. In this first picture L is the parallel distance along the datum across the reference plane But in this second picture L is the length along the pipe Why are the two L's...

Hi, I have to solve one equation on Matlab. The equation is: (p-c)*psi'-psi=0 I have to find p. Where psi is: and psi' is the derivative of psi. I've written this code: rho = 0.04; %In the image is lambda c = 25; eta = 0.02; mu = 40; sigma = 0.57; alpha = -rho/eta; syms p t F =...

I am having some issues with this problem I am doing. I will show what I have done so far and where I am getting confused. 1. Homework Statement The 2-port shown in Figure 2 is characterized by its Z-parameters, where ##Z_{11}=Z_{12}=Z_{21}=Z_{22}=R##. Find the input impedance ##Z_{in}##...

Is the multiverse universe so vast that everything has or will happen?

https://en.wikipedia.org/wiki/Immirzi_parameter Quote:The Immirzi parameter seems to be the only free parameter of vacuum LQG Hence LQG should provide formulas (or numerical calculation) for all dimensionless parameters of standard model . For now, at least the raw idea, where they come from...

Motivation: I am working with a code that minimizes the objective functional value in an optimal control problem. It takes $A_1,A_2,A_3,A_4$ (the balancing factors for various components of the objective functional) as inputs, and then outputs the values of the state variables, control...

Another paper in Friday's physics arXiv on using the H(z) v z plot to investigate any possible evolution of DE: Utility of observational Hubble parameter data on dark energy evolution. From that eprint: As discussed in the Marginal evidence for cosmic acceleration from Type Ia SNe, this paper...

At first, we need some state parameters(like P/T/V) to fully describe a system. And the order parameter is also a parameter which could describe the property of the system. However, in the Laudau theory, why it said that order parameter is an external parameter(not a independent variable)? Is...

Hello, I am attempting to eliminate the parameter from r'(θ) = r'(θ)=<-10sinθ,10cosθ> , but when I do, I get back to the same equation as I would for eliminating the parameter for r(θ)=<10cosθ,10sinθ> (1) x^2 + y^2 = 10 y = \sqrt{10-x^2} (2) y' = \frac{-x}{\sqrt{10-x^2}} then, since x^2...

Mod note: I revised the code below slightly, changing the loop control variable i to either j or k. The reason for this is that the browser mistakes the letter i in brackets for the BBCode italics tag, which causes some array expressions to partially disappear. Hello, I am trying for the first...

As a part of our exercise we need to determine the lattice parameter of the given xrd peaks (http://bama.ua.edu/~mweaver/courses/MTE481/Lab2_PP.pdf . the last page of the link), here's the peak data: 2theta 23.73 39.23 46.36 56.69 62.31 71.1 76.15 84.35 89.2 97.29 102.21 110.83 115.9 luckily...

...r than 1? This is the slide we have been given in class So what on Earth would the structure of PA, PC and PE be? I understand the closer to 1 it would be a bilayer so PC is likey a bilayer but can't understand what the others would be from this slide, does anyone have any ideas?

I am trying to solve a large least squares inversion (inverting data for the modeled sources), and find that my parameters describing 1 source are highly correlated with the parameters describing the second source. Can anyone recommend a technique or reference which discusses how to reduce the...

x = 2 − π cos t y = 2t − π sin t −π ≤ t < π I understand how to eliminate parameter using sin^2 + cos^2 = 1. I can't figure out how to deal with the "2t" in the y equation, if you solve for sin(t) and square, you get ((2t-y)/π )^2 which leaves the parameter. Is there a way to get it into the...

I have \begin{figure}[h] ... \end{figure}, but it's just placing the figure at the top of the page. do i need some package? which one? thanks very much.

For the distance function ##(\Delta s)^2 = (\Delta r)^2 + (r \Delta \theta)^2##, the rotation matrix is ##R(\theta) = \begin{pmatrix} cos\ \theta & - sin\ \theta \\ sin\ \theta & cos\ \theta \end{pmatrix}##. That means that for the distance function ##(\Delta s)^2 = (\Delta r)^2 +...

If ##\sigma## is an affine paramter, then the only freedom of choice we have to specify another affine parameter is ##a\sigma+b##, a,b constants. [1] For the tangent vector, ##\xi^{a}=dx^{a}/du##, along some curve parameterized by ##u## My book says that ' if ##\xi^{a}\xi_{a}\neq 0##, then by...

Hello, this is my first post here, so if I do problems, please correct me and do not be upset = ) I have one small theoretical and one greater question. small one first: Homework Statement I have a potential energy : $$W(L)= -\frac{1}{4}k_4(L_x^4+L_y^4+L_z^4)$$ How can describe my potential...

Hi all, I am trying to obtain an empirical equation/model having 2 inputs (frequency and S11) and one output (a physical parameter) I have done various simulations using CST of the System and now I am trying to relate S11 and frequency to a physical parameter. Any suggestions of how I should go...

Homework Statement Find the speed parameter β and Lorentz factor γ for an electron that has a kinetic energy of: a) 6.00 keV b) 2.00 MeV c) 4.00 GeV Homework Equations KE=(γ-1)*511 KeV SQRT(1/(1-β^2))=γ The Attempt at a Solution a) 6 KeV=(y-1)*511 y=1.0117 1.0117=SQRT(1/(1-β^2)) β=0.152 b)...

Homework Statement Prove that Homework Equations [/B]The Attempt at a Solution Without cosmological constant, one finds that where w is the ratio between pressure and density.[/B]

Dealing with CMB, people sometimes refer to the shift parameter; R = \sqrt{\frac{\Omega^0_m}{\Omega^0_k}}sinh(\sqrt{\Omega^0_k}\int^{z_{dec}}_{0}{\frac{dz}{E(z)}}) I know that it is related to the position of the first acoustic peak, however, the amount is around 1.7. What does this mean?! does...

I have a question about the logistic fit they used on this paper: http://online.liebertpub.com/doi/pdf/10.1089/cmb.2005.12.1047. Its PDF page 5, or journal page 1051. They define all the variables and then say x0 and b define the shape of the model. If I am fitting 30 cycles of PCR data how am I...

This is probably a stupid question but does k=1,0,-1 correspond to closed,flat,open refer to space or space-times? Looking at a derivation what each geometrically represents is only done when talking about the spatial part of the FRW metric. As space can be flat and space-time still curved...

Hi everyone! I am trying to find the parameters of a surface mounted PM synchronous motor using the application note AN4680 (PMSM Electrical Parameters Measurement) and had some queries regarding it. The Ld process is mentioned as follows 1. Align the rotor to phase A. Phase A is connected to...

Homework Statement So I have been asked to design a PD Controller on Matlab that satisfies certain performance criteria which are as follows : 1. The 10-90% rise time is less than 0.5 s 2. The percentage overshoot is less than 5%. 3. The settling time is less than 5 s I was given the closed...

Homework Statement 2-1. A constant torque of 4 Nm is applied to an unloaded motor at rest at time t = 0. The motor reaches a speed of 1717 rpm in 4 s. Assuming the damping to be negligible, calculate the motor inertia in Nm·s2. Homework Equations T = J(eff) * dw/dt J = kg*M^2 The Attempt at a...

A line in 2-dimensional euclidean space can be determined by the coordinates of any two particular points on the line. Hence four "parameters" are required. Now let’s consider a line given by the usual equation y = mx + c. c, being the intercept on the y-axis, is related to the point (0,c) which...

I've understood that the main evidence for a non-zero ##\Omega_\Lambda## comes from supernova 1a measurements where one measures the redshifts along with the luminosity distances (equivalently magnitude) of the supernovae and, plots them against each other, then compares the result with...

For those of you who know what a Hansen Solubility Parameter is, does the "hydrogen-bonding" part means the actual hydrogen bond energy between molecules? I'm confused as to why they used mPa^0.5 instead of kJ/mol^-1 for measurement.

Hi, suppose that you have some function: F(x;a) where x is the variable with which you plot the function and a is some parameter which enters the function. If I want to find the error coming from some uncertainty in a, computationally, I would have to plot the function for 2 different let's say...