Displaying 20 results from an estimated 2000 matches similar to: "Multivariate Autoregressive Model calibration and residual testing"
2011 Jan 12
0
Multivariate autoregressive models with lasso penalization
I wish to estimate sparse causal networks from simulated time series data.
Although there's some discussion about this problem in the literature (at
least a few authors have used lasso and l(1,2) regularization to enforce
sparsity in multivariate autoregressive models, e.g.,
http://user.cs.tu-berlin.de/~nkraemer/papers/grplasso_causality.pdf), I
can't find any R packages with these
2006 Mar 14
2
problem with optim: (list) object cannot be coerced to 'double'
Hi,
I am trying to use optim to solve a heavy calibration problem. I supply
the parameters in vector form. But before entering my target
The call is simply:
optim(par = parameters, fn = SumLSQ, method = "Nelder-Mead")
the function SumLSQ is simply:
SumLSQ<-function(parameters, data = timeseries){
print("sumLSQ")
nbseries =
2009 Mar 31
1
Jarque-Bera test and Ljung-Box test for multivariate time series
Hi!
I know that there is function in fBasics package for univariate Jarque-Bera
test and a funtion for univariate Ljung-Box test in stats package. But I am
wondering if there is a function somewhere to do the tests for multivariate
time series?
Thanks,
John
[[alternative HTML version deleted]]
2008 Apr 24
0
Coefficient of determination in a regression model with AR(1) residuals
Dear R-users,
I used lm() to fit a standard linear regression model to a given data
set, which led to a coefficient of determination (R^2) of about
0.96. After checking the residuals I realized that they follow an
autoregressive process (AR) of order 1 (and therefore contradicting
the i.i.d. assumption of the regression model). I then used gls()
[library nlme] to fit a linear
2006 Mar 13
1
Vector Autoregeressive Models: Adequation tests to perform
Hello,
I am currently testing a Vector AR of dim 3 over not a lot of data (135
* 3 observations) . To test the adequation of my vecot ar, I use the
Schwarz Bayesian Criterion and the classic modified Portmanteau test on
the residuals (it can be found for instance in
http://www.iue.it/PUB/ECO2004-8.pdf , page 15) -> the null hypothesis is
"the residuals process are a vectorila white
2006 Feb 15
1
question about the results given by the Box.test?
Hello, I am using the Ljung Box test in R to compute
if the resiudals of my fitted model is random or not.
I am not sure though what the results mean, I have
looked at various sources on the internet and have
come up with contrasting explanations (mainly because
these info deal with different program languages, like
SAS, SPSS, etc).
I know that my residuals should appropriate white
noise( is
2004 Jan 13
3
How can I test if a not independently and not identically distributed time series residuals' are uncorrelated ?
I'm analizing the Argentina stock market (merv)
I download the data from yahoo
library(tseries)
Argentina <- get.hist.quote(instrument="^MERV","1996-10-08","2003-11-03", quote="Close")
merv <- na.remove(log(Argentina))
I made the Augmented Dickey-Fuller test to analyse
if merv have unit root:
adf.test(merv,k=13)
Dickey-Fuller = -1.4645,
2004 Jan 14
0
How can I test if a not independently and not identicallydistributed time series residuals' are uncorrelated ?
I'm analizing the Argentina stock market (merv)
I download the data from yahoo
library(tseries)
Argentina <- get.hist.quote(instrument="^MERV","1996-10-08","2003-11-03", quote="Close")
merv <- na.remove(log(Argentina))
I made the Augmented Dickey-Fuller test to analyse
if merv have unit root:
adf.test(merv,k=13)
Dickey-Fuller = -1.4645,
2011 Feb 25
0
time series with NA - acf - tsdiag - Ljung-Box
Hi all,
I am modelling a time series with missing data.
*Q1)* However, I am not sure if I should use the next *graphics* to
understand my data:
*a)* ACF & PACF (original series)
*b)* ACF & PACF (residuals)
* *
*Q2)* I am using *tsdiag*, so I obtain a graphic with 3 plots: stand.
residuals vs time; acf for residuals; Ljung-Box for residuals (it is wrong
for residuals).
I know that using
2008 May 16
2
Box.test degrees of freedom
Dear colleagues,
I am new to R and statistics so please keep that in mind.
I have doubts on the df calculation of Ljung-Box test (Box.test). The
function seems to use always the df=lag=m and not df=m-p-q like suggested in
Ljung and Box (1978) paper (that is referenced).
Do you agree with this? If so, is there an R package function that computes
Ljung-Box test with the degrees of
2004 Apr 17
3
Box-Ljung p-value -> Test for Independence
Hi all
I'm using the Box-Ljung test (from within R) to test if a time-series in
independently distributed.
2 questions:
1) p-value returned by Box-Ljung:
IF I want to test if the time-series is independant at say 0.05
sig-level (it means that prob of erroneously accepting that the
time-series is independent is 0.05 right?)
--> then do I consider time-series as "independant"
2011 Aug 27
1
Degrees of freedom in the Ljung-Box test
Dear list members,
I have 982 quotations of a given stock index and I want to run a Ljung-Box
test on these data to test for autocorrelation. Later on I will estimate 8
coefficients.
I do not know how many degrees of freedom should I assume in the formula for
Ljung-Box test. Could anyone tell me please?
Below the formula:
Box.test(x, lag = ????, type = c("Ljung-Box"), fitdf = 0)
2009 Feb 24
1
Box.test reference correction (PR#13554)
Full_Name: Peter Solymos
Version: 2.8.1
OS: Windows
Submission from: (NULL) (129.128.141.92)
The help page of the Box.test function (stats) states that the Ljung-Box test
was published in:
Ljung, G. M. and Box, G. E. P. (1978), On a measure of lack of fit in time
series models. Biometrika 65, 553--564.
The page numbers are incorrect. The correct citation should be as follows:
Ljung, G. M.
2008 Nov 19
2
simulation of autoregressive process
Dear R users,
I would like to simulate, for 20000 replications, an autoregressive process: y(t)=0.8*y(t-1)+e(t) where e(t) is i.i.d.(0,sigma*sigma),
Thank you in advance
____________________________________________________
Écoutez gratuitement le nouveau single de Noir Désir et découvrez d'autres titres en affinité avec vos goûts musicaux
2007 Aug 07
1
Functions for autoregressive Regressionmodels (Mix between times series and Regression Models) ?
Hello everybody,
I've a question about "autoregressive Regressionmodels".
Let Y[1],.....,Y[n], be a time series.
Given the model:
Y[t] = phi[1]*Y[t-1] + phi[2]*Y[t-1] + ... + phi[p]*Y[t-p] + x_t^T*beta + u_t,
where x_t=(x[1t],x[2t],....x[mt]) and beta=(beta[1],...,beta[m]) and u_t~(0,1)
I want to estimate the coefficients phi and beta.
Are in R any functions or packages for
2002 Dec 10
1
autoregressive poisson process
Dear R users,
I am trying to find a package that can estimate
an autoregressive model for discrete data. I am
imagining a Poisson or Gamma process in which the
mean (say mu) follows a process such as
mu_t = a + b*x + c*mu_{t-1}
Suppose I have data on the time-series Poisson
outcomes and x and would like to obtain ML estimates
for b and c.
Does anyone know of a package that can do this
2010 Mar 01
2
Simple Linear Autoregressive Model with R Language
Hello -
I need to do simple linear autoregressive model with R software for my
thesis. I looked into all your documentation and I am not able to find
anything too helpful. Can someone help me with the codes?
Thanks
Emil
[[alternative HTML version deleted]]
2011 Jul 27
0
Conditional Autoregressive Value at Risk (CAViaR)
Hi,
I am trying to replicate Engle and Manganelli's paper Conditional
Autoregressive Value at Risk (CAViaR) by Regression Quantiles. I have the
Matlab code which I cannot get to work as I have never used Matlab before,
does anyone know if there is the same code available to estimate the CAViaR
models in R?
Thanks,
Shane
--
View this message in context:
2008 Feb 15
1
Conditional Autoregressive (CAR) model simulation
Hi all !
I would like to simulate spatial lattice/areal data with a conditional
autoregressive (CAR) structure, for a given neighbouring matrix and for a
autocorrelation "rho".
Is there any package or function in R to perform it ?
I found the function "CARsimu" in the hdeco library, but this is not what
I'm looking for
Thanks in advance
Dae-Jin
--
2012 Jul 07
0
regressor & autoregressive error?
Hello,
I am using R for fitting parameters of a time series model.
The model is as below.
Y(t) = mu + a*X(t) + YN(t)
where YN(t) = b*YN(t-1) + innovation
and Z(t) follows N(0,1).
The main obstacle for me is the autoregressive error term, YN(t).
I can't figure out how to estimate the parameters (mu, a, b) with usual
'arima' function in R.
What I have tried is....
1. Do the