What is Parameter: Definition and 392 Discussions

A parameter (from the Ancient Greek παρά, para: "beside", "subsidiary"; and μέτρον, metron: "measure"), generally, is any characteristic that can help in defining or classifying a particular system (meaning an event, project, object, situation, etc.). That is, a parameter is an element of a system that is useful, or critical, when identifying the system, or when evaluating its performance, status, condition, etc.
Parameter has more specific meanings within various disciplines, including mathematics, computer programming, engineering, statistics, logic, linguistics, electronic musical composition.
In addition to its technical uses, there are also extended uses, especially in non-scientific contexts, where it is used to mean defining characteristics or boundaries, as in the phrases 'test parameters' or 'game play parameters'.

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  1. P

    Analysis method to describe impact of variables on parameter

    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...
  2. H

    B What is the self absorption parameter

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

    Need Help to Calibrate Semiconductor Parameter Anlyzer 4156B

    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...
  4. M

    A Obtain parameter derivatives solving PDE

    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 $$B = k_1\cdot C^a$$...
  5. NATURE.M

    Stuck on obtaining a closed form for parameter using MLE

    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}...
  6. S

    F(R) gravity and the Hubble parameter

    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...
  7. avikarto

    Approximation with small parameter

    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...
  8. W

    MHB Bayesian parameter estimation via MCMC?

    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...
  9. S

    MHB Find Mean Formula With Penalty as Parameter

    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...
  10. L

    How to use the b&h tcspc in experments of quantum optics?

    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...
  11. B

    Estimating the Parameter 'a' from ODE System

    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
  12. S

    Why is impact parameter not directly measurable?

    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?
  13. ognik

    Closest approach with impact parameter

    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...
  14. ognik

    MHB Eliminating t: Solve $4x+3y=0$

    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}...
  15. B

    Impact parameter of a photon in Schwarzchild metric

    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...
  16. H

    Determine the lattice parameter

    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...
  17. beyondlight

    Typical transistor design parameter [W/L]

    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...
  18. **Mariam**

    Pendulum periodic motion; period parameter

    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...
  19. yango_17

    Arclength parameter for a path with exponential and trigonometric functions

    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...
  20. T

    I Confusion Over Hydraulic Gradient, L parameter

    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...
  21. FrancescoMi

    MATLAB Solving One Equation on Matlab: Finding Parameter p

    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 =...
  22. X

    Solve Z Parameter Questions: 2-Port Network w/ R Load

    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}##...
  23. S

    B Exploring the Boundless Possibilities of the Multiverse

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

    The Immirzi Parameter: Unravelling Gravity's Weakness in Vacuum LQG

    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...
  25. K

    MHB Optimal Control Parameter Values: Converge/Fail?

    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...
  26. Garth

    Utility of observational Hubble parameter data on DE

    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...
  27. D

    The difference between order parameter and state parameter?

    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...
  28. O

    Eliminating Parameter for <-rsinθ,rcosθ> ≠ assumed function

    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...
  29. Angelos K

    LAPACK dgeev: parameter had illegal value

    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...
  30. R

    Determine the lattice parameter of Tetragonal system

    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...
  31. R

    What if the packing parameter of a lipid structure is greate

    ...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?
  32. V

    Least squares parameter correlation

    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...
  33. M

    Eliminate Parameter with Sin and Cos

    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...
  34. binbagsss

    H parameter to place figure 'here' not working

    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.
  35. S

    Scaling the parameter of the SO(2) rotation matrix

    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 +...
  36. binbagsss

    Product of Tangent Vectors & Affine Parameter

    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...
  37. enot

    Parameter for a saddle point

    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...
  38. L

    S11 and Frequency Modeling for Physical Parameter

    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...
  39. R

    Speed parameter β and Lorentz factor γ

    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)...
  40. A

    Prove evolution of Hubble parameter

    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]
  41. S

    How can you show the CMB shift parameter?

    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...
  42. R

    4 parameter logistic model for fitting PCR data

    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...
  43. binbagsss

    FRW Metric: Parameter k & Space/Space-Time Relationships

    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...
  44. A

    PM sychronous motor parameter measurement

    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...
  45. J

    Optimizing PD Tuner Parameters for Improved Performance: A MATLAB Study

    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...
  46. D

    Find moment of inertia via torque and acceleration parameter

    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...
  47. G

    Which parameter am I missing in determining a straight line?

    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...
  48. C

    Assumptions in dark-energy density parameter measurement

    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...
  49. P

    What Units are Used for Hansen Solubility Parameter?

    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.
  50. ChrisVer

    What is the best method for plotting function parameter errors?

    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...
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