Displaying 20 results from an estimated 6000 matches similar to: "Time series analysis"
2007 Nov 11
5
Multivariate time series
Hello to everyone!
I have a question for you..I need to predict multivariate time series, for
example sales of 2 products related one to the other, having the 2 prices
like inputs..
Is there in R a function to do it? I saw dse package but I didn't find what
a I'm looking for..
Could anyone help me?
Thank you very much
Giusy
--
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2007 Oct 24
0
Package forecast
Hello All,
I trying to use the function auto.arima(....) from package forecast but I
have a problem.
My steps after I used the function auto.arima(...)
I create the time series like this:
>bbrass = scan("C:/Program Files/R/data PTIN/my_file.dat")
>regts.start = ISOdatetime(2006, 7, 1, hour=0, min=0, sec=0, tz="GMT") #2006
07 01 00
>regts.end = ISOdatetime(2006, 7,
2007 Nov 26
3
Time Series Issues, Stationarity ..
Hello,
I am very new to R and Time Series. I need some help including R codes
about the following issues. I' ll really appreciate any number of
answers...
# I have a time series data composed of 24 values:
myinput = c(n1,n2...,n24);
# In order to make a forecasting a, I use the following codes
result1 = arima(ts(myinput),order = c(p,d,q),seasonal = list(order=c(P,D,Q)))
result2 =
2011 Jun 15
1
Query regarding auto arima
I am using AUTO ARIMA for forecasting. But it is not detecting 'seasonality
term' of its own for any data.
Is there any other method by which we can detect seasonality and its
frequency for any data?
Is there any method through which seasonality and its frequency can be
automatically detected from ACF plot?
--
Siddharth Arun,
4th Year Undergraduate student
Industrial Engineering and
2011 Jun 15
1
Problem auto.arima() in R
I am using auto.arima() for forecasting.When I am using any in built data
such as "AirPassangers" it is capturing seasonality. But, If I am entering
data in any other format(in vector form or from an excel sheet) it is not
detecting seasonality.
Is there any specific format in which it detects seasonality or I am doing
some thing wrong?
Does data have to be entered in a specific
2007 Apr 16
0
Impute missing values within a time-series
Hi everyone.
I have to deal with a time series data and I'm looking for some
methodological help. The time series starts in January 1992 and until
April 1996 (52 observations) the values are ok (there is some trend
and seasonality in the data, but nothing special). From Mai 1996 to
June 1997 no observations were recorded, thus these 14 observations
are missing (NA). Starting from July 1997
2010 Aug 30
1
How to Remove Autocorrelation from Simple Moving Average time series
Hi R experts,
I am trying to remove autocorrelation from Simple Moving Average time series. I know that this can be done by using seasonal ARIMA like,
library(TTR)
data <- rnorm(252)
n=21
sma_data=SMA(data,n)
sma_data=sma_data[-1:-n]
acf(sma_data,length(sma_data))
2005 Sep 08
1
Interpolating / smoothing missing time series data
The purpose of this email is to ask for pre-built procedures or
techniques for smoothing and interpolating missing time series data.
I've made some headway on my problem in my spare time. I started
with an irregular time series with lots of missing data. It even had
duplicated data. Thanks to zoo, I've cleaned that up -- now I have a
regular time series with lots of NA's.
2007 Jun 14
1
ARIMA with more than one seasonality period
Dear R community,
I have a project with electricity load forecasting, and I got hourly
data for system load. If you haven't worked with electricity before,
seasonality comes in many flavors: a daily pattern, with a peak at
around 7pm; a weekly pattern, in which we use more electricity on
weekdays in comparison to weekends; a winter-summer pattern, with air
conditioning and heaters playing an
2007 Dec 04
1
Best forecasting methods with Time Series ?
Hello,
In order to do a future forecast based on my past Time Series data sets
(salespricesproduct1, salespricesproduct2, etc..), I used arima() functions
with different parameter combinations which give the smallest AIC. I also
used auto.arima() which finds the parameters with the smallest AICs. But
unfortuanetly I could not get satisfactory forecast() results, even
sometimes catastrophic
2002 Sep 23
0
arima() in package ts.
I've been trying to get comfy with arima() and associated functions
in the ts() package. I'm thinking seriously about using this
package, and R generally, in a 4th year intro time series course that
I'm teaching this autumn.
I have a couple of questions about arima:
(1) The help file says that residuals component of the value returned
by arima() consists of the
2007 Nov 08
1
Help me please...Large execution time in auto.arima() function
Hello,
I using the fuction auto.arima() from package forecast to predict the values
of p,d,q and P,D,Q.
My problem is the execution time of this function, for example, a time
series with 2323 values with seasonality to the week take over 8 hours to
execute all the possibilities.
I using a computer with Windows XP, a processor Intel Core2 Duo T7300 and
2Gb of RAM.
2012 Nov 14
0
Time Series with External Regressors in R Problems with XReg
Hello everyone,
Hope you all are doing great! I have been fitting arima models and
performing forecasts pretty straightforwardly in R.
However, I wanted to add a couple of regressors to the arima model to see if
it could improve the accuracy of the forecasts but have had a hard time
trying to do so.
I used the following R function:
arima(x, order = c(0, 0, 0),
seasonal = list(order = c(0, 0,
2002 Jul 30
1
Comparison of two time series using R
We have two time series: the first is a series of weekly counts of
isolates of RSV (respiratory syncytial virus) by pathology laboratories,
and the second is a series of weekly counts of cases of bronchiolitis in
young children presenting to hospital emergency departments.
Bronchiolitis in young children is usually caused by RSV infection, and
simple visual inspection reveals a very close
2012 Jun 25
0
x12 ARIMA Moving Seasonality F Test Issue
I'm having a great deal of trouble replicating x12 ARIMA's F-test used to
detect moving seasonality. According to all literature I could find, the
test is apparently a 2-way ANOVA with year and month as factors for the SI
ratios determined by x12's smoothing algorithm. Note the SI ratio is simply
the detrended series. The summary I get from manually running this 2-way
ANOVA using the
2004 May 25
1
Tramo-seats support in GRETL, but not R
On Mon, 24 May 2004 12:00:46 +0200 v.demartino2@virgilio.it wrote:
> Working - among other things- in the field of (short & long term)
electricity
> forecast,
* * *
> we have to comply with the Tramo-seats closed-source procedure
(http://www.bde.es/informes/be/docs/dt0014e.pdf)
> to deal with seasonality of electricity monthly time-series, in line
with
> the methodology
2008 Jun 18
1
Complex Time Series
Hi R masters,
In my work I analyse a time serie of number of birth in State of Rio de Janeiro.
After study de ACF e p ACF I conclude the model is:
Non seasonal ar(1)
In 7 days lag 7 days seasonal ma(1)
In 364 days lag 364 days seasonal ma(1)
If the time serie was Non seasonal ar(1) with one seasonal ma(1) is simple
using command arima for fit a time serie, but I don't know HOW TO fit a
2005 Mar 16
2
How to concatenate time series?
Hello,
I have just completed first experiments in using R, especially creating and
using ARIMA models, e.g.
# create a model as in example(arima)
fit <- arima(USAccDeaths, order = c(1,1,1),seasonal = list(order=c(1,1,1)))
# use the model to generate a prediction
dp<-predict(fit, n.ahead = 24)
plot(dp$pred) # view the prediction
Now I created a combined chart of the original and
2011 Dec 12
1
Question about fitting seasonal ARIMA in R?
Hi all,
I just couldn't find a R function which can fit multiple seasonal
patters... i.e. in the following code:
*arima(x = data, order = c(p, d, q), seasonal = list(order = c(P, D, Q),
period = S), ...
***
*
there can be only one "period", am I right?
What if the data seem to have three different seasonality cycles, 5, 12, 21?
Thanks a lot!
*
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2007 Nov 21
1
problem modeling time series
Good afternoon!
I'm trying to model a ts but unfortunately i'.m very new to this kind of modeling so i 'll be very grateful if you have an advice.
This was my syntax: