sepdek

sepdek October 9, 2016

A function is a rule that maps each of the elements in a domain to one and only one element in a range. The set of all possible elements in the input is the domain D of a function; the set of all possible elements in the output is the range R of a function. […]

sepdek October 8, 2016

Formally stated, the derivative of a function of the form with k a constant and with respect to an independent variable x, is simply, I find this to be extremely handy in all cases. Consider the simple case in which, In the same way, In a more complex example, In an even more complex example, […]

sepdek October 8, 2016

The thing starts with invariance, conservation and symmetry… Invariant is something that is unchanged by a coordinate transformation. Conserved is something that is unchanged by a process within a given coordinate system. Symmetry could be considered a broader property of some ‘universe’ in which some entity of interest remains the same under a specific operation. […]

sepdek October 8, 2016

In order to be a measure (distance) d must:   In order to be a metric (distance) d has to be a measure and:   …and here is the cheat sheet:  

sepdek June 2, 2016

Strangely, although anyone can add somebody in a Twitter list, Twitter does not offer a simple “Remove me from list X” option. Adding somebody to a list is not controlled by the person being added, at least in the default Twitter setting. Nevertheless there is a way, rather awkward way that is, to remove oneself […]

sepdek June 20, 2015

Recently I have been experimenting with MIT app inventor 2 on the Web to check the development cycle and production time. It turns out that the platform is extremely productive and offers numerous features for Android app development. In a day I have been able to develop a relatively simple app and in two hours […]

sepdek November 24, 2014

A newly developed remote monitoring app for Android devices has been published on the Google Play store. The application is a miniaturised version, which provides just a few remote measurements served by a data server. The application is heavily based upon the work of Maria Pappou and Christos Zaptses, which have originally developed an arduino-android […]

sepdek October 22, 2014

Since the Yosemite update a few days back, I decided to give Mac Mail another chance. One really annoying thing that I had to face right from the beginning was the lack of a keyboard shortcut for a “must” option to “Erase Deleted Items” “In All Accounts…” (quoting the menu options). There is an incredibly […]

sepdek October 14, 2014

I have recently finished developing a simple eHealth project that includes a health sensor kit and an iOS 8 app published through the App Store (*currently my developer account is suspended due to the capital controls in Greece). The project is called ‘i-Health’ for all the known reasons. The application offers a live medical monitoring […]

sepdek August 8, 2014

The only way that I found to delete multiple photos from the iPhone (iOS 7) without having to select them one-by-one or, at best, ‘Moment’-wise, was to use Preview on my mac! Preview has a magical option in the ‘File’ menu which is called ‘Import from iPhone…‘. This option opens a window showing all photos […]

sepdek May 15, 2014

It has been many years working on digitization, reconstruction and virtual world applications; tested and used various techniques covering almost all aspects in the digital recording workflow. In the recent past years our team has been successfully engaged in a very productive workflow regarding digitization and reconstruction in 3D. Specifically, this workflow involved the application […]

sepdek March 14, 2014

A straightforward approach to do geometric image transformations using MATLAB is to take advantage of the imtransform function available. First the image is supposed to be within a ‘unity’ rectangle and initial transformation conditions are defined accordingly: udata = [0 1]; vdata = [0 1]; fill_color = 128; org_rect = [0 0;1 0;1 1;0 1]; […]