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. Maged Saeed

    MHB What are the parameters for the printf function in the C language?

    As I know each function can have no parameter this function is called void function ,for example main function, also there is some functions which has one or more parameters either input or output , the number of parameters should be specified in the function prototype and function definition...
  2. M

    Is My Matrix Approach to Solving Linear Equations with Parameters Correct?

    Homework Statement hi. i have a linear equation with parameters that i am trying to solve. unknowns are x, y and z. (12-3t)x + 2y +2z =2 x +0*y +2z =0 12x + (2-t)y + (2-t)z = 12 i am using a matrix-approach with Gaussian-elimination, and my results (for values of t which allows for a...
  3. P

    How to prove Any curve in space can be written as for a parameter

    how to prove Any curve in space can be written as for a parameter
  4. pedroall

    Order Parameter in a Gauge Theory, Can we find one in a Gauge Theory(like QCD)?

    Hello Community! I can't find a good answer(if there is) to my question. When in statistical mechanics we can define the order parameter for to study some phase transition. we need to define a order parameter. Now, I want to know if we can to define/find some "order parameter" for to...
  5. 2

    What exactly is the Hubble parameter?

    I'm looking at general relativity and particularly considering what happens at the Big Bang. I think the Friedman equation is H^2=\frac{8\pi G}{3}\rho so I see that as the matter density goes to infinity, H goes to infinity. According to this video (around 10:10), this is where the problem lies...
  6. V

    On nonlinearity parameter in Nonlinear Schrodinger Equation (NLS)

    While I am studying the wave propagation in fluids, the amplitude modulation seems to be governed by the Nonlinear Schrodinger (NLS) equation. In some of the journal papers the nonlinearity parameter, N seems to be of high value (N≈O(104)) and so on. I understand that weak nonlinearity...
  7. L

    Time derivative of Hubble parameter

    Is rather a question of calculus skills, but how do I get the time derivative of the Hubble parameter here in [1]? Is it the Leibnitz rule, the chain rule, some clever re-arrangement? thank you
  8. Daaavde

    Difference between coupling constant and strength parameter

    Hello to everyone, I got a little bit confused between the coupling constant g_W and the strength parameter \alpha_W in the weak interaction. For what I know they should both give an idea of the strength of the interaction but I miss to understand what's the difference between them.
  9. Mogarrr

    Parameter space for the negative binomial distribution

    Homework Statement For the negative binomial distribution, with r known, describe the natural parameter space Homework Equations the pmf for the negative binomial distribution with parameters r and p can be 1) P(X=x|r,p)= \binom {x-1}{r-1}p^{r}(1-p)^{x-r} where x=r,r+1,... , or 2)...
  10. A

    What is the significance of normalized data in NMOSFET parameter extraction?

    Hey! I'm doing a lab assignment and need some guidance. i have measurement with L=1μmeter and w=10μmeter, but the id data is normalized to w=1μmeter, what does it mean? do I need to get Ids "un-normalized" for extraction, like Ids*1e-6= new Ids the second question is about low-field...
  11. ChrisVer

    Cosmological constant deceleration parameter

    Homework Statement Give q(t) the deceleration parameter, as a function of: \Omega_{\Lambda}, the cosmological constant density, and \bar{a}(t) = \frac{a(t)}{a(t_{0})}= 1+ H_{0} (t-t_{0}) - \frac{1}{2} q_{0} H_{0}^{2} (t-t_{0})^{2} where a's the scale factors have already defined τ =...
  12. AwesomeTrains

    Existence of limit of a function with a parameter

    Homework Statement For what values of a, from the reals, does the limit exist? lim_{x\rightarrow2} (\frac{1}{2-x}-\frac{a}{4-x^{2}}) Homework Equations I chose a so that the denominator would be one. By putting the fractions together. The Attempt at a Solution When a = 4 the...
  13. H

    Help eliminating parameter for harmonic trig combination

    Hey guys, I'm reading the Theory of Sound and I've come to a part in which I'm having trouble double-checking the algebra. Suppose we have two harmonic sound waves of equal amplitude traveling directly perpendicular to each other. \begin{align} u=acos(2πnt-ε) && v=bcos(2πnt) \end{align} They...
  14. L

    Orienational order parameter in isotropic systems

    Hi everyone, I have what may be a dummy question. In NMR or in the study of liquid crystals for example, an order parameter S is often used: S=\left\langle\frac{1}{2}\left(3\cos^{2}\theta-1\right)\right\rangle with \theta the angle of the molecule with a "director" (the magnetic field in...
  15. C

    Perpendicular planes, solve for parameter a

    Homework Statement Determine for what value/s of the parameter a the following planes in R3 are perpendicular: ax + 0y - 5z = 3 ax + ay + 5z = -26 Write answer in form {a,b} or {a} Homework Equations I know that in R2 two vectors are perpendicular if u*v = 0 What what do I use for...
  16. R

    Leibniz rule for differentiating an integral w.r.t a parameter

    Homework Statement I have the functionu(x,t)=\frac{1}{2c}\int^{x+ct}_{x-ct}g(\xi)d\xiwhere g is continuously differentiable and c is a constant. I need to verify that this is a solution to the wave equation. Homework Equations My prof gave me the...
  17. Y

    Proof of Arc Length Parameter

    1. The problem statement, all variables and given/known If C is a smooth curve given by r(s)= x(s)i + y(s)j + z(s)k Where s is the arc length parameter. Then ||r'(s)|| = 1. My professor has stated that this is true for all cases the magnitude of r'(s) will always equal 1. But he wants me...
  18. R

    Finding the Uncertainty of the Slope Parameter of a Liner Regression

    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...
  19. N

    Comp Sci Fortran77 woes- single parameter least squares minimisation stuck

    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...
  20. N

    Fortran Fortran77 woes- single parameter least squares minimisation stuck

    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...
  21. C

    Calculating Probability of a Poisson Process w/ Parameter λ

    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]) >...
  22. Z

    Dimensional Analysis with non-dimensional initial parameter

    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.)...
  23. Dilatino

    Why does the Schwinger parameter correspond to proper length?

    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...
  24. H

    Is the Critical Density Related to the Friedmann Equation?

    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...
  25. ShreyasR

    H parameter analysis of transistor amplifiers.

    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...
  26. anemone

    MHB Find the values of the parameter "q"

    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 $q$...
  27. D

    Limit of a sequence, with a real parameter

    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...
  28. N

    Optical design: BPP beam parameter product M^2 and beam expander

    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...
  29. C

    Parameter Scaling for Optimization

    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...
  30. Y

    MHB System of linear equations with a parameter

    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...
  31. R

    Deceleration Parameter Computation

    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}##...
  32. MarkFL

    MHB Calculus Tangent Line: Find Parameter k | Camille's Q&A

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

    Estimate exponential distribution parameter

    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...
  34. M

    Computing an Integral with a limiting parameter

    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...
  35. S

    U parameter in hexagonal unitcells

    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?
  36. N

    How Does the H Parameter Model Calculate Current and Voltage Amplification?

    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
  37. L

    Trying to make the connection with QM as a 1 parameter QFT

    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...
  38. N

    A question about H parameter model

    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...
  39. D

    Dividing by a parameter that is zero

    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...
  40. B

    Why did they choose to estimate the parameter this way.

    Hello, I am taking an introduction class to statistics, in an earlier exam excercise they choose to estimate the answer in an odd way. To make my question concise I will make an abstraction of the problem, and not go into the details, but I can give you them if you'd like aswell. In the...
  41. S

    Graded Index Fiber's Optimal Grade Profile Parameter P = 2

    This was something I was thinking about yesterday regarding graded index optical fibers. So since most graded index fibers adhere to the power-law function for its refractive index profile of the core shown below: n^2 (r)=n_1^2 [1-2(\frac{r}{a})^p ∆], r≤a, where ∆...
  42. S

    Finding the Minimum Mean Square Estimator for Scalar Parameter w

    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))...
  43. F

    Linear System with Parameter: Solutions and Homogeneity

    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...
  44. marcus

    Which: scale or years? as parameter of change

    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...
  45. Petrus

    MHB Find Parameter Producing Line l Through Points P and Q

    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
  46. MarkFL

    MHB Kaleigh's question at Yahoo Answers involving eliminating a parameter

    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.
  47. A

    Lawson Parameter for Sustained Deuterium-Deuterium Fusion

    Homework Statement Calculate the minimum Lawson parameter for sustained deuterium-deuterium fusion in a plasma with an energy of 10 keV. Homework Equations The Lawson parameter is given as $$ n \tau > \frac{12 k T}{<\sigma v> Q} $$ where \sigma is the fusion cross-section. The Attempt at a...
  48. WannabeNewton

    Differentiation under integral sign - one parameter family

    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...
  49. V

    Parameter Estimation, Non Linear Least Squares, Newton-Raphson

    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...
  50. C

    Using Hubble parameter defn to change integration variable from t to a

    Homework Statement r1 = t∫t1 1/a(t) dt Use the Hubble parameter definition to change from t to a, if a(t) = a and a(t1) = 1 Homework Equations Hubble parameter H = a' / a where a' = da/dt The Attempt at a Solution Start with Hubble parameter definition, and rearrange to find dt aH =...
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