### Technology

#### Differentiation cheat sheet

October 13, 2016

This post serves as a cheat sheet for differentiation. It just includes the most basic of the rules to be remembered when computing derivatives. First a little reminder on the notation being used in differentiation. Leibniz’s notation for the first derivative of a function f(x) is Newton’s notation for the first derivative of a function […]

#### On critical points of functions

October 12, 2016

There is a really large number of applications in engineering, in which the identification of critical points of a function is crucial for the analysis and modeling of a process or a system. Generally, one may identify three kinds of critical points, that is (a) maxima, (b) minima and (c) saddle or stationary inflection points. […]

#### Functions and graphs primer

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. […]

#### Handy & powerful differentiation method

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, […]

#### A short note on functionals, conservation, invariance and symmetry

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. […]

#### Measure and Metric cheat sheet

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:

#### Remove from a Twitter list

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 […]

#### DIGARCH 2015

July 17, 2015

DIGITAL TECHNOLOGIES IN CULTURAL HERITAGE & TOURISM 11 Days equivalent workload to 130 hours (incl. 20 hours essay), 5 ECTS 30 July – 10 August 2015 Delphi, Greece Complete summer school programme. COURSE: Introduction, current state-of-the-art, innovation, trends UNIT: Innovative applications of technology in cultural heritage and trends for future research and development PDF edition […]

#### JSON data on the Android mobile with App Inventor 2

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 […]

#### Remote monitoring app (tiny version) is on Google Play

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 […]

#### Mac Mail automation

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 […]