find an equation for data points with disturbances - MathOverflow [closed] most recent 30 from http://mathoverflow.net 2013-05-21T06:04:29Z http://mathoverflow.net/feeds/question/75834 http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://mathoverflow.net/questions/75834/find-an-equation-for-data-points-with-disturbances find an equation for data points with disturbances eng_sub 2011-09-19T11:11:15Z 2011-09-19T11:11:15Z <p>Hello,</p> <p>I have a question regarding how to find an equation for data points that have</p> <p>disturbances.</p> <p>For example, I have the following data:</p> <p>P = 366 measured values </p> <p>T = 366 measured values</p> <p>t = [ 1 : 366 ], representing the days of the year (index)</p> <p>So, at each t (day), we have value of P and corresponding value of T</p> <p>When drawing P and T vs. t, it shows a continued curve for P with disturbances. These</p> <p>disturbances are caused by the change of T and it is clear that P is mainly affected</p> <p>by T, meaning that: P = f ( T )</p> <p>This figure is shown here:</p> <p><a href="http://store2.up-00.com/Sep11/VKq30182.jpg" rel="nofollow">http://store2.up-00.com/Sep11/VKq30182.jpg</a></p> <p>This figure shows P vs. T:</p> <p><a href="http://store2.up-00.com/Sep11/esZ30295.jpg" rel="nofollow">http://store2.up-00.com/Sep11/esZ30295.jpg</a></p> <p>My aim is to find this relation between P and T or in another words: P = f ( T )</p> <p>What I have tried and think so far is first to smooth the curve P and from the smoothed</p> <p>points and smoothed curve, some function may be established. Then, including the</p> <p>effect of disturbances (up and down) by some function, may be exponential.</p> <p>Could you please guide me how can I manipulate this problem to get a final model </p> <p>P = f ( T ) . </p> <p>Regards</p>