Parameter Definition and 352 Threads

Finding the Uncertainty of the Slope Parameter of a Linear Regression Suppose I have measurements x_i \pm \sigma_{xi} and y_i \pm \sigma_{yi} where \sigma is the uncertainty in the measurement. If I use a linear regression to estimate the value of b in y=a+bx, I'm struggling to find a...

Hey guys! Having issues with a code I'm writing. It doesn't fit the typical format and I may have already accidentally posted it in the wrong forum, so here's a copy of what was there with the newest version of the code. It'll (eventually) be a four-parameter least squares minimisation, but for...

Hey guys! Having issues with a code I'm writing. It'll (eventually) be a four-parameter least squares minimisation, but for the moment I'm just trying to get the single parameter version to work. I've got the first module done but, when I run it it gets caught up in a loop and doesn't actually...

I need some help on the following question: Let N() be a poisson process with parameter \lambda . I need to find that probability that N((1,2]) = 3 given N((1,3]) > 3 I know that this is equal to the probability that P(A \cap B) / P(B) where A = N((1,2]) and B = N((1,3]) >...

I would like non-dimensionalize the equations which describe a non-Newtonian fluid model. In the constitutive equation (power-law model) there is a non-dimensional parameter: n. According to Buckingham's Pi theory, I must take all the relevant independent parameters (variables, constants, etc.)...

I have just learned from nice article http://motls.blogspot.com/2013/12/edward-witten-what-every-quantum.html that the propagator of a massive particle can be rewritten as an integral over the so-called Schwinger parameter t as $$ \frac{1}{p^2 + m^2} = \int\limits_0^\infty dt...

Homework Statement For a κ=0 universe with no cosmological constant, show that H(z)=H0(1+z)3/2 Homework Equations Friedmann equation: H2=\frac{8*\pi*g}{3c^2}-\frac{κc^2}{r^2}*\frac{1}{a(t)^2} The Attempt at a Solution I know that R(z)=R0/(1+z) but I do not know where this comes...

In h parameter analysis, we take the input current and output voltage as independent variables. and the Input voltage and output current are dependent on the input current and output voltage. They are related as: Vin = h11Iin + h12Vout ___(1) Iout = h21Iin + h22Vout ___(2) In case of a...

Hi MHB, Problem: Find the sum of all positive real values of the parameter $q$ for which the equation $(x^2+4x+4+136)^2=16q(5x^2+4x+136)$ has exactly three distinct real solutions. Answer: $q=9$ and $q=34$. I am aware the question is actually asking us to find all possible values of $q$...

Homework Statement Find a, sucht that: \lim_{ x \to \infty }( a \sqrt{n+2} - \sqrt{n+1} ) ) = \infty(a+1) Now, I want this sequence to have the limit 0. The first impule is to say that a+1 = 0 and hence a = -1. But if I do this I get \infty 0 which can't be determined. The paradox is...

We work on optical simulation where we use not ideal beam expander. Not ideal means that for beam expander designed for single mode (M^2=1), the output beam has M^2 >1 (M^2 = M squared) In our system we want to use beam expander with multimode laser beam. The beam expander is not ideal (for...

So I am still confused about how to applying scaling of parameters to a general optimization problem. Let's say I am trying to do maximum likelihood estimation. I understand how to find the scaling matrix (assuming we restrict it to diagonal form) and that the Hessian should be close to the...

Hello all, I need your help with this tricky problem. Determine the value of \[\lambda\] so that the following linear equation system of three unknowns has only the zero solution: \[\begin{pmatrix} 1 &1 &1 &0 \\ 1 &\lambda &1 &0 \\ \lambda &1 &1 &0 \end{pmatrix}\] I have started working on...

Hi everyone, Can anyone point me into the right direction on how to compute the deceleration parameter (##q_0##) for a radiation dominated universe? I know that q0 is given by ##q_0=-\frac{\ddot{a}(t_0)}{a(t_0) H^2 (t_0)} = - \frac{\ddot{a}(t_0) a(t_0)}{\dot{a}^2(t_0)}=\frac{\Omega_0}{2}##...

Here is the question: I have posted a link there to this topic so the OP may see my work.

Homework Statement A certain type of transistor has an exponentially distributed time of operation. After testing 400 transistors, it is observed that after one time unit, only 109 transistors are working. Estimate the expected time of operation. Homework Equations The Attempt...

Hi All, I am reading a paper in which the following integral is presented $$\int_{-\infty}^{ct-x} \int_{-\infty}^{ct-x} J (2t - \frac{2x+s_1+s_2}{c}) \frac{\mathrm{d}f (s_1)}{\mathrm{d}s_1} \frac{\mathrm{d}f(s_2)}{\mathrm{d}s_2} \mathrm{d}s_1 \mathrm{d}s_2$$ where J and f are unknwon...

Hi, I have encountered in the papers that people present a, c and c/a as the parameters measured for any hexagonal unit cell. But what is u (angstrom) that sometimes appear among the parameters of a hexagonal unit cell?

Homework Statement calculate current and voltage amplification The Attempt at a Solution Conversion to h parameter model, and this is my working step, https://www.filesanywhere.com/fs/v.aspx?v=8b6b628b5e646faf6e9b

I'm seeing lots of underlying connections between the canonical formulism of QFT and QM. But I'm getting a bit confused by their differences. I'll just write down my thought process: QM is a one parameter system (t) in a space with three quantized operators (x,y,z) QFT is a four parameter...

Homework Statement consider all those capacitor is a short circuit for the ac current. I am to find i) Input impedance, ii) output impedance iii)voltage gain, Av = Vout / Vin iv) current gain, Ai = Iout / Iin The Attempt at a Solution So i first draw the H parameter model...

Hi, I'm studying calculus of variations, this is a bit of a recap of regular calculus. You got a function, but you plug a vector that is parameterized so your function becomes parameterized, then you take the derivative in 3.5, and then they say: put the parameter to zero in 3.6, but then you...

I am not able to understand how to go about this problem: Find the minimum mean square estimator for the scalar parameter w based on the scalar observation z = ln w + n where f(w) =1 if 0<=w<=1; 0 else: and f(n) =e^-n if n>= 0; 0 else I did f(z/w) = (f(n))...

Homework Statement I have done this exercise, but I don't have a file with the solutions. COuld you please check it? Thank you in advance :) Given the following system: ##\lambda \in \mathbb{R}## ##x − z = \lambda## ##x + y + 2z + t = 0 ## ##y + 3z = ## ##x + z + t = 0## 1-find...

The first stars formed when distances were 9% of their present size. The solar system began forming when distances were 70% of what they are now. Andromeda galaxy will make a first pass through Milkyway when they're 129% of present. Which do you find more meaningful and intuitive for...

Hello MHb, Decide one parameter producing for line l through the points $$P=(1,1,2)$$ and $$Q=(2,-3,5)$$ This is a exempel from my book, I understand how they got the first line but not the second, (I hope that it don't mather it's on Swedish) Regards, $$|\pi\rangle$$

Here is the question: Here is a link to the question: Find the equation in the xy-plane whose graph includes x = cos t and y = sec t.? - Yahoo! Answers I have posted a link there to this topic so the OP can find my response.

Hi guys! Let \left \{ B_{t} \right \}_{t\in \mathbb{R}} be a one - parameter family of compact subsets of \mathbb{R}^{3} with smooth (manifold) boundary (e.g. one - parameter family of closed balls). In my context, each B_{t} belongs to a different constant time slice of Minkowski space - time...

Hello, Homework Statement I want to estimate a set of parameters by trying to minimize the sum of squares wrt to the parameter set given a simulation of a markov process and real data in Matlab. I have already implemented the Levenberg-Marquart (LM) Algorithm and it is converging to certain...

For which values of a,b and c, the next function is continuous and differentiable at x=2 ? \left\{\begin{matrix} 3x-1 & x\leq 2\\ ax^{2}+bx+c & x>2 \end{matrix}\right. 1. b=2-c 2. b=6+2c+2a 3. 7+c-2a 4. b=3-a-(3/4)c I know that f(2)=5, and so is the limit of f when x goes to 2 from the left...

Homework Statement Find \iiint (x^{2n} + y^{2n} + z^{2n})\,dV where the integral is taken over the region of 3D space where x^{2} + y^{2} + z^{2} \leq 1 Homework Equations The Attempt at a Solution I tried doing this in Cartesian coordinates, but the limits of integration got...

Hi All, I'm trying to solve the following derivative with respect to the scalar parameter \sigma $$\frac{\partial}{\partial \sigma} \ln|\Sigma|,$$ where \Sigma = (\sigma^2 \Lambda_K) and \Lambda_K is the following symmetric tridiagonal K \times K matrix $$ \Lambda_{K} = \left(...

When calculating whether Boltzmann, Bose-Einstein, or Fermi Dirac should be used there is an equation for Degeneracy Parameter A which can be initially used. Degeneracy Parameter A = (N/V) (h^2 / 2 TT m k T)^(3/2) What is represented by N and V and k? Is N the Number Density, V Volume and k...

Homework Statement The problem is Q2 in the attached Homework Equations The Attempt at a Solution I am trying to determine the rigion of parameters for each number of crosses,where x and y are the distances of the center of cross from the closest line respectively,and θ is the acute angle.I...

Could you check my solution please? Homework Statement find out for which values of ##\lambda>0## the sequence ##(a_n)## ,defined by ##a_1 = \frac{1}{2}, \quad\quad a_{n+1} = \frac{1}{2} (\lambda +a_n)^2, \quad n\in \mathbb{N^*}## converges. If ##(a_n)## converges, find the limit. The...

Homework Statement Decide the density parameter from the following data: z=0.04, m= 17.38 and σ=0.19 Homework Equations Definition of the density parameter: Where p0 is the current density and pc is the critical density. The Attempt at a Solution I feel like I don't...

in the dimensional regularization of the QED we introduct an arbitrary parameter μ with the dimension of a mass... so there are finite terms that are function of μ... so they are arbitrary? how we can fix this parameter? what is the physical meaning of μ?

Homework Statement The problem is to get the classical turning point as a function of the impact parameter b for the Lennard-Jones potential. Homework Equations The Lennard-Jones potential is given as [itex]V(r)=4\epsilon[(\frac{\sigma}{r})^{12}-(\frac{\sigma}{r})^6][\itex]. The effective...

hello I am jagodzziski from poland i would like to ask u about PSIM software actually I am doing single phase SPWM inveter voutput 12V 50HZ .. may i know what parameter for igbt and may u show me the calcultion tq

I am recently trying to identify system parameters with projection algorithm, but faced a problem, and the dynamic model is the following: \ddot{y}(t)+a\cdot\dot{y}(t)=b\cdot e(t) The true value of a is 2.8, b is 0.1. While inputing volt e(t)=12sin(2\pi t)+5sin(2t), I can get a good...

Homework Statement In class we derived the Schwarzschild interior solution (constant density). Examine the behaviour of non-radial null geodesics in this spacetime.Homework Equations \Phi(r)=ln\left(\frac{3\sqrt{1-\frac{2M}{R}}}{2}-\frac{\sqrt{1-\frac{2Mr^2}{R^3}}}{2}\right)...

I'm looking at using AICc to compare a set of nested models and wondered about the following. First, my the errors in my n data points around the fit are not i.i.d. Gaussian (the data have an artifact that the models will not able to fit easily and the artifact introduces dependencies and a...

Homework Statement Eliminate the parameter to find a Cartesian equation for the curve. X=sin(t), y=csc(x) Homework Equations The Attempt at a Solution Is this correct? X=sin(t) Arcsin(x)=t So y=csc(arcsin(x) Can I simplify it further?

Homework Statement In a HW assignment, I'm given the ODE y' = f(x,y,\epsilon) and that y = \phi(x,\epsilon) is a solution to this equation. I'm then asked, is \phi(x,0) a solution to the equation y' = f(x,y,0) This result is used for the second part of the problem, and in...

From what I think I understand, a variable is something you input into a function and you get a certain value from it whereas a parameter is something that gives you a different function but 'adjusted'...so the constant C the translates a graph of a function up and down would be a parameter...is...

Hi, I am looking for information on how to extract circuit parameters. I have a system, and I can experimentally perform current and voltage measurements. For example, I can measure the voltage response of the system as a function of a given input pulse. In addition, I also have an...

Homework Statement Consider the following linear system of equations: x1+2x3-5x4 = 0 x1 + 4x2 +4x3 – 5x4 = 10 x1 + 2x2 + 3x3 – 5x4 = 5 4x1 + 2x2 + 9x3 – 20x4 = 5 b) Solve the equation system with the Gaussian method. c) The solution set describes a plane. Specify it in the parameter...

Homework Statement Discuss for alpha the convergence of the following improper integral: \displaystyle \int\limits_{0}^{3}{\frac{{{x}^{3\alpha }}}{{{\left( 9-{{x}^{2}} \right)}^{\alpha }}}} Homework Equations The Attempt at a Solution Well, my attempt was to simplify the integral to...

I'm trying to find the determinant of a band diagonal matrix that has a parameter, κ, in some of the entries. Some entries are just numerical ones, others (κ X number), while others are (κ + number). I have been told that they way to solve for κ is to find the determinant of the this matrix and...

This is from Matts Roos' text on cosmology. I don't follow the final step and when he integrates I understand the first part of the left side, and the right side. But I don't see where -a'^2(t0) comes from