In a reCAPTCHA test, as shown below, two words are shown to the visitor.
#BU MATLAB 2009 SOFTWARE#
Recognition (OCR) software failed to recognize. reCAPTCHA tries to useĬAPTCHA tests for a secondary useful purpose, helping to digitize old printed material by asking users to decipher scanned words from books that optical character ReCAPTCHA is a recent implementation of this idea by the original creators. Today it is estimated that about 200 million CAPTCHAs are solved around the world eveyday.
The term CAPTCHA was coined in 2000 by Luis von Ahn, et.
#BU MATLAB 2009 CODE#
Human being can read the distorted text, but a computer code can not. Usually a distorted text is shown to the visitor of the web site and he/she is asked to enter the text back. Common uses are to prevent spam comments in blogs, protect website registration, prevent computerized mass votingįor online polls, etc. Is a human or an automated computer program. I love GUIs.ĬAPTCHAs (Completely Automated Turing Test To Tell Computers and Humans Apart) are codes used in several websites to decide whether the visitor I am planning to write similar interfaces, first for the timeĭependent 1D code and later for the 2D code. In a few seconds you can play with the constants of the differential equation, change the number of elementsĪnd/or their polynomial orders, provide a set of different boundary conditions and obtain a new solution. With GUIs like this one it is veryĮasy for the instructors to do such quick demostrations. It shows the importance of proper mesh refinement for a successful and efficient FEM solution. The solution given below is for the same problem, but this time the mesh is clustered towards to end of the domain It demostrates the typical failure of Galerkin FEM technique when the local Peclet The solution shown above is for the well known advection-diffusion problem.
It is also possible to save the input data of a problem to a file and read later, so that we don't need to fill in the text boxes again and again. Also the result is plotted on the same window, which makes our FEM solver really compact and easy to work with. Simply provide all the necessary data through this GUI. We don't need to generate those files anymore. But it was time consuming and prone to typos. With a couple of hours of study I managed to come up with a nice little FEM solver that looksīefore this GUI we were providing the inputs through text files. Possible to use the GUIDE tool that comes with MATLAB to design GUIs. This semester I decided to write a Graphical User Interface (GUI) to one of my 1D FEM codes. Of these codes and solving some test problems using them. During the semester I provide simple 1D and 2D educational MATLAB codes to my students and I assign homework about completing certain missing parts
#BU MATLAB 2009 MOVIE#
To play the movie again right click on it and select Play.įor the finite element course that I am teaching this semester we use MATLAB as aĬomputing tool. To get physically correct results we need to reduce the time step. Actually the given advection velocity, element size and time step combination falls to the unstable region of this scheme and the The third run is for the explicit Euler scheme,
These trailing waves can be eliminated by using more elements. Unphysical trailing waves behind the actual cosine hill. As seen, its diffusion errors are much less than the implicit Euler case. Scheme is known to be unconditionally stable, but as seen from the movie it is highly diffusive. The first one is for alpha=1, which corresponds to the implicit Euler time discretization. The movie shows three simulations with three different alpha values. For time discretization alpha family schemes are used.
Exact solution at this final time should be a cosine hill with a height ofġ, centered at x=1.2. 50Įqui-spaced elements and a constant time step of 0.01 is used. Initial condition is hard coded to be a smooth cosine hill with a height of 1, centered at x=0.2. The following movie shows this new GUI in action. Modified the GUI so that time dependent advection-diffusion equations can be solved. I extended the underlying code to solve unsteady problems and In the previous post, I mentioned about the little MATLAB GUI that I wrote for a 1D FEM solution.
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