I am trying to use Holt-Winters method in order to do time-series prediction on some datasets. The problem that I'm dealing with is the fact that each dataset has different seasonality value (or frequency basically). As an example, in one dataset the trend occurs every 300 timesteps while for another one this might be a different number. Assuming that I do not have the option of visualizing data each time to find out about the seasonality of my data, what would be the best way for finding the optimal value of frequency to get the best performance from Holt-Winters? Note that I receive about 500 out of 4000 samples to train my model.  My approach: Split train data to train and validation subsets. Use different seasonality values on train and evaluate performance on validation. For now, I think I'll use random search to find the best value such that it minimizes the prediction error on validation set. I was wondering if there are any other practical methods or approaches that any of you might be aware of?  UPDATE: I have to mention that I have to implement this only in python and not R, so the findfrequency() function from forecast package is applicable here.
This post is the continuation of another post related to a . Basically, at this point I'm interested in a robust way to discover the periodicity/seasonality of a generic time series affected by a lot of noise. From a developer point of view, I would like a simple interface such as:  unsigned int discover_period(vector&lt;double&gt; v);  Where v is the array containing the samples, and the return value is the period of the signal. The main point is that, again, I can't make any assumption regarding the analyzed signal. I already tried an approach based on the signal autocorrelation (detecting the peaks of a correlogram), but it's not robust as I would like.
What are the best ways to improve a site's position in Google? What are the best ways to improve a site's position in the Google search results? Python Flask shutdown event handler "a" or "an" in front of a word beginning with a vowel I was writing a text when I came to say 'a union', then it struck me that I need to change the 'a' to 'an'. But for some reason, 'an union' didn't sound right.   Why doesn't it work? Is it because its a mass noun, instead of a regular noun? Why is there a discrepancy in disk usage reported by df and du? I have a Linux CentOS server, the OS+packages used around 5GB. Then, I transferred 97GB data from a Windows server to two folders on this Linux server, after calculated the disk usage, I see the total size of the two folders is larger than the disk used size.  Run du -sh on each folder, one use 50GB, the other one use 47GB  But run df -h, the used space is 96GB. (50GB + 47GB + 5GB) > 96GB  Is there any problem? Those two folders contain lots of files (1 million+). Thanks. Can't save my render as an image I seem to be having issues when I try and save the output file as a .png, or .jpeg for that matter. I've set up my user preferences, File, Render Output to my desktop as well as render output in the editor window. What am I missing here? I'm obviously very new to this program and your help would be appreciated. Thanks for your time What is the probability that a shuffled standard deck of 52 cards has no two cards of the same rank together ?  I am unable to get a handle on this problem, and wonder whether there is an analytical solution ? Parallel file copy from single source to multiple targets? I have a several large files on optical media I would like to copy to multiple targets - in this case I have two hard drives attached to the same computer. Is there a utility that can function like:  copy source target1 target2 ... targetN What is the preferable setup for MiKTeX to keep all packages up-to-date easily? Value of having done applied math research when applying to PhD programs in pure math I will be a second year math under-grad in September, and currently doing an internship at applied math research institute. Most probably, I will come up with a research paper at the end of the internship.  However, my interest after my bachelors is to do PhD in pure math from a top math school.My question is this:     Would the admission committee consider my current research since it is in applied math?    In addition, if anyone can suggest me some ideas on how can I bridge the gap between my paper in applied math and my interest in analysis, I would be extremely grateful.  P.S.:  is a related but different question also of mine. Sci-Fi book female fighter pilot All I remember about the book is that the protagonist was a human female fighter pilot, she has short hair, not sure if it was blond or auburn and she was involved in making peace with the alien race.  The alien race was invading Earth, but because of her they stopped, surrendered and because of her helped Earth improve its technology. I remember that she melded with something and was starting to sort of think like them and lose a bit of her humanity.  It was set in the not too distant future. I believe I read it in the 90s. Extrude and bevel an imported svg curve I exported an svg 1.1 file from Adobe Illustrator CS6. I joined all the shapes by pressing Ctrl+J. I set the curve shape to 2D. Then I extruded using the right hand side panel:    So far so good. But when I try to apply even a slight bevel, all hell breaks loose:    It does get less insane if I bring the bevel down by multiple factors of 10... But then I really don't have much of a bevel.  Am I doing something wrong? Am I using the wrong kind of object? Should I be doing this with meshes? Do my curves just need cleaning up? 80/90s UK children's drama series about an "alien" boy with radio weapon I've been trying to track down a live-action children's TV series (or short story perhaps) from the 1980s or 1990s, probably on CBBC or CITV.  A few people I've spoken to IRL have suggested The Boy from Space or Sky, but I'm pretty sure it's neither as a lot of the details don't seem to match.  The story was set on Earth (possibly England or Wales) and was about an "alien" boy who was being pursued by a group of people, though I don't remember who they were.  Somehow he encountered siblings, a girl and a boy, and made friends with them. I think they lived on a farm with their parents, as I remember quite a large barn or other building, and they hid(?) the boy in a car which was inside or next to this building. He also slept in this car with a dog (which might have been a German shepherd).  The "alien" boy had a portable "radio" (all silver, very 1980s) that repelled his pursuers by emitting a high-pitched sound when he turned a dial on it, and he used it when out and about with the other children whenever they encountered a pursuer. I seem to remember lots of hills and valleys, lots of green.  In the end it turned out he wasn’t really an alien, but a human from the far future. He was pretending to be an alien as he was from 20000 years into the future and humans' appearance had changed by then, but he had the ability to make himself look like current-day humans. When he was in his car/bed he reverted to his normal appearance, so he would hide under the blankets until he was able to assume current-day human appearance.  In the finale, it was revealed that he was never in any danger – the pursuers were testing him as part of a kind of coming-of-age thing. I remember a scene on a spaceship or something where his elders/parents where shown telling him that he was safe all along and that he "passed".  I also seem to remember them referring to "ancestors" and making sure they didn't find out, so the either the girl or boy could well have been a direct ancestor. Difference between force.com and salesforce.com? What the difference between the two?  This description seems to be a bit out of date and underspecified. There appears to be a giant security vulnerability with Android that seems to basically affect all phones.  wrote:  The vast majority of Android phones can be hacked by sending them a specially crafted multimedia message (MMS), a security researcher [Joshua Drake] has found. ... Drake found multiple vulnerabilities in a core Android component called Stagefright that’s used to process, play and record multimedia files. Some of the flaws allow for remote code execution and can be triggered when receiving an MMS message, downloading a specially crafted video file through the browser or opening a Web page with embedded multimedia content. ... The MMS attack vector is the scariest of all because it doesn’t require any interaction from the user; the phone just needs to receive a malicious message. For example, the attacker could send the malicious MMS when the victim is sleeping and the phone’s ringer is silenced, Drake said. After exploitation the message can be deleted, so the victim will never even know that his phone was hacked, he said.  What can a regular user do to mitigate the issue? Disable Google Hangouts? I've watched the Vampire Knight anime. I really like the story so far but find it frustrating that the anime doesn't finish off the story. I'm trying to figure out if it is worth reading the manga.  Does the manga contain more story than the anime? Does it finish the story off? $\max(\{n: n+5 | n^5 + 5\})$ What is the maximum value of $n$ if $n + 5$ divides $n^5 + 5$, $n$ being a natural number? I tried to solve by binomial theorem but it failed. Why can I no longer easily navigate inside of this mesh? How to truncate all logfiles? Ought we only form beliefs based on sufficient empirical evidence? states that the relationship between current ( I ) voltage ( V ) and resistance ( R ) is  $$I = \frac{V}{R}$$  However  cause the resistance of a material to go to zero, and as I understand it, as $R \to 0$, $I \to \infty$. Does this present a problem for Ohm's law?