Signals can be any time-varying or space-varying quantity. Examples: speech, temperature readings, seismic data, stock price fluctuations. A signal has one or more frequency components in it and can be viewed from two different standpoints: time-domain and frequency domain. In... Continue Reading →

To find a basic introduction of GA, the first part can be found here. III. Examples using Genetics Algorithm In these examples, we will use Matlab and its function ga to apply GA for the optimization problem. For the manual... Continue Reading →

I. Introduction In daily life as well as in doing research, we might come to problems that require a lowest/highest value of variables, e.g.: find the shortest way from home to work, buying household items with a fixed amount of money,... Continue Reading →

In Earth Science research, sometimes we need to construct 3D surfaces from given points, for example: creating the fault surface, locating a subducting slab from earthquake hypocenters, etc. in a region of interest in X-Y plane. In this example, we... Continue Reading →

Earthquake location problem is old, however, it is still quite relevant. The problem can be stated as to determine the hypocenter (x0,y0,z0) and origin time (t0) of the rupture of fault on the basis of arrival time data of P... Continue Reading →

In seismology, we usually have to deal with the sac data format (binary data format). This data format can be dealt easily and efficiently with the SAC software provided by IRIS. But if we want to use this data in... Continue Reading →

Doing statistical analysis in MATLAB is lot easier than other computer languages. Here, we can make use of the intrinsic "plot" to visualize the statistics of the data. Below are some programs for commonly used statistical analysis: Calculating mean, standard... Continue Reading →

Text data which is in one format all through the file is easier to read. But when the text data has numeric entries, string entries (different data formats), then it becomes little complicated to read and write. Sometimes, the data... Continue Reading →

If we need to run the same algorithms or formula for computations again and again, then instead of writing the same stuffs in our script file many times, we can simply write a function. This makes our script look simpler... Continue Reading →