Graph of a data hub with a relational database at the center

Your data hub

The general idea

You’re likely to just start making your data with whatever software seems ‘natural’ to you. However, hold on for a moment, and consider the near future of your research project. Your table, notebook, network graph, or what have you, may quickly turn into a data hub. Perhaps you should consider a relational database.

Basic pros and cons of a relational database

One important trademark of relational databases is that they are relatively flexible. To be precise, the data stored in tables and woven together through relationships, can easily be changed. Tables can be split up, data can be moved from one to another. Relationships can be redefined, et cetera.

Secondly, relational databases are also quite good at importing and exporting data. In particular exporting is very easy. One can bring data together in a particular view, if only for the export, and export it to the outside world, often in different file formats.

Thirdly, relational databases are not particularly suited for data analysis, although they often come packed with basic possibilities to summarize, do simple statistics, and generate graphs. However for more advanced scientific analysis they are simply not suited. The reverse is also true: the software that is suited for advanced analysis usually does not offer the same flexibility to rearrange data as relational databases do.

These traits make a relational database an excellent hub for your research data. You produce and maintain your data in the database and when the time comes, you export it as needed, import and import it in other software for analysis. This is illustrated in the figure.

Continue reading here for additional topics:
• But, you only use one type of software for analysis?
• Dealing with inflexibility
• Knowing when to start the hub

Digital history group on LinkedIn

If you are a historian with an interest in digital issues, then consider joining the LinkedIn group on digital history.

You find it here.

All new pages on relational databases will be announced there.

The choice of software depends on the structure of your research data

Your choice of research tools is probably determined through your history. Your education and research experience have lead you to certain instruments of choice, that feel ‘natural’ to you. However, from time to time you may want, or are forced to, reconsider. There are some aspects to this. To name some: function ( What do you do with the tool? ), data structure ( What kind of data are you processing and what does it look like? ), costs and availability, ease of migration ( Can you move your data to the other software? Can you move it away again? ), transfer-ability to colleagues ( If you collaborate or hand over, how easily will your colleagues deal with your software? ). Here, I will look at the structure of your data. I will show some examples of research data and discuss which software is in my view best suitable to handle the data.

Continue reading here

How to change the world – book review

A dear friend of mine, M., recommended this book to me when I asked him for feedback on my project in the summer of 2017. A couple of years earlier, when I was looking for a completely new job, he had recommended another title ‘How to find fullfilling work’ from the same series called ‘The school of life’. Since that was such a success I couldn’t wait to read ‘How to change the world’. The read was definitely worth my while, but I finished it with mixed feelings, which I will briefly explain in the first section.

Besides that I realised I can read it in two ways: On the one hand, it offers a lot of practical help for the phase of my project where I feel I know what should be done to get more people doing more things that our planet and humanity need. On the other hand it also implicitly and explicitly gives some answers to my question, which are the topic of the second section.

Continue reading here

Lego, MOC, Mindstorms NXT 2 quick release, trigger pulled

Quick release for Mindstorms NXT 2.0

As a side-product of the robot ball that I am building now, I developed a quick-release box for the Mindstorms NXT 2.0. It has a nice trigger mechanism that you might be able to use in your own Mindstorms MOC. Check out this page for the design, more pictures and a demo movie.

Black woodpecker

This morning, on the walk with Kika, I saw a black woodpecker having breakfast four or five meters away from me. It is supposed to be shy, but it didn’t fly off. Maybe it didn’t see me because the sun was right behind me. Anyways, I managed to make a video.

More wildlife photos here.


Truncated icosahedron v2 – a lot stronger

Earlier, I made a truncated icosahedron (a football if you will) out of Technic Lego. A downside of the design was that the ball was not very strong. It would loose a bit of shape under it’s own weight, and a lot more if you pressed it. I developed three stronger designs for the hexagons (see below), but got distracted by other projects. Today, back on this track, I finished a new version based on the design at the far right. And indeed, it is a whole lot stronger. It can roll easily and even stand some pressure. Since the pentagons are not reinforced and there is a tiny bit of slack in the hinges, it still looses a bit of shape, but I think it’s within limits for my purpose.  So, I will now continue with the interior, to make it a mindstorms-driven self-rolling robot ball, or ball bot, or whatever.

20181117 Hexagon reinforcement designs - cropped lowres