Why is estimating the effort necessary for a software development project so much more complicated than estimating the construction of a building? Because a software development project is a new project with mostly new people and often new technology for every new project.

Once again I had to experience that the estimation for a project was too optimistic. It is easy to estimate the expectable effort if yourself will be the person who has to realise the project. I remember that all estimations I did for myself where exact.

But as soon as the project is larger and is about a new business area, you have to do more work. You will have to do different kinds of estimations, for example a SCRUM story point estimation, a comparison with a similar project, a function point analysis and so on.

Now, there is the cone of uncertainty which tells us that an estimation done before the projects requirements were investigated properly could be far far away from the real effort you will spend. And the estimation will only come down to a more realistic value if you do another estimation after the requirements are clearer or even after you have started developing.

 

DynamoDBNoSQL-Database is something quite new. I heard the first time about it a couple months ago and even read an interesting article about the topic which was in truth too complicated for me.

But recently I run into the question who a web shop like Amazon is storing its data. Surprisingly this is no secret and Amazon has published a description about their technology and you can even download an API to connect to the database and you can create your own DynamoDB on the Amazon cloud.

Here is a short summary about the concept in German. I had no time to translate it into English so far. Hope it is correct from a technical point of view!

Mandelbrot Excel

Mandelbrot Excel

Here is the result. It took me only minutes to implement it and as you can see in the different sheets, I have also implemented the Julia set in the same workbook.

The sheets are for 3 different resolutions and you see that the range where both sets are visible is from -2.2 / -1.5 to 0.8 / 1.5 for the Mandelbrot set and from -1.8 / -1.5 to 1.8 / 1.5 for the Julia Set.

I realized the different colors with conditional formatting which is a nice feature of Microsoft Excel. Points which are part of the set are black, points which are not part of the set are colored. The color depends on the number of iterations necessary to decide that they are diverting and is going from red and yellow to white.

You can download the Excel workbook from here. You might have to allow the basic script!

Julier Set

Julier Set

I am a fan of the Mandelbrot set since I have seen it the first time. I developed a screen saver for windows which displays the Mandelbrot set and zooms in randomly.

I also tried to develop something similar for the iPhone but did not succeed for the time. When I was investigating possibilities to draw lines in HTML code, I saw that with HTML 5 there is a new tag <Canvas> which allows exactly what I need.

Here is the result. I have created a page which shows the Mandelbrot set and the same for the Julia set. Both are very impressive. You can zoom in by clicking somewhere in the graph and even move the graph with the mouse.

Here is the page with the Mandelbrot set and
here is the page with the Julia Set.

Edimax IC-3110W

Edimax IC-3110W

I just bought a network camera and was wondering how easy it is to install such a thing at home. Network cameras are very cheap nowadays. I just payed CHF 130,– including delivery. My model is a wireless model which has motion detection, email delivery and a night modus.

You have to connect it to power and enable the device on your router and it is connected. There is a nice web interface to change settings and you can just browse the IP and see the video. It even comes with an iPhone app which does video streaming.

Making it accessible from outside was much harder and cost me a couple of nights. Finally it worked when I assigned the camera a fix IP address and put it into the de-militarized zone in my router. With a normal Cablecome internet contract you do not get a fix IP address, so you have to use DynDNS.com or No-IP.com to solve this problem.

But now it works, and after having installed everything, I must say that it was easier than expected.

Growing Tornado

Growing Tornado

It’s unbelievable but I was able to take a photo of a tornado! Were sitting in the restaurant of our hotel in Cyprus about 2 pm after having lunch and suddenly saw something coming out of a cloud looking like a finger.

First I was not sure but when I looked at it for a couple of seconds I saw that it really was growing. I told my wife to take a picture and ran to our room to get the kids to the restaurant to see it too.

When we were back it was already grown down to earth and looked like a real tornado. It was just in front of us, maybe 2 kilometers distance. I never have seen something like that and I am sure not a lot of people have.

It’s a pity that we forgot to take a video. Would have been much nicer. The whole thing had a duration of about 3 minutes, then it was over.

Tornado finished

Tornado finished

When is was down to earth it started getting thinner and thinner and vanished within seconds.

And I am also sure that you get only once in your like the opportunity to see something like that in reality and to be able to take a picture.

The whole thing was really only about 3 minutes until it was gone and I was able to see it from the beginning.

I just was nipping on my coffee when I looked at the dark cloud expecting a flash and thunder every second, when I saw the little white finger coming down slowly.

Khan Academy

Khan Academy

I saw an article about Sal Khan a couple of weeks ago in Times magazine. I think it was the version where they portrayed the most influential people of the year 2011. On of the persons of 2011 was Sal Khan, the founder of an online academy. I was interested and had a look at the web site and was immediately impressed.

Now I am watching more and more videos. I am especially interested into the topic economy where Sal explains a lot about the current problems of US economy. But I also already watched videos about biology, maths and history.

The videos are about 10 minutes and Sal is able to explain things so easy that everybody should be able to follow him. I even able to follow him though its all English.

The most impressive videos so far were about evolution, bankruptcy, US elections and so on. Very impressive!

Light Pollution

Light Pollution

The stars are away. When I was a boy, I can remember that you could saw the stars of the milk street. It was very fascinating. Sometimes, especially in winter we made a walk in the night with the parents and I wonderd about the millions of stars you could see.

Have you ever seen the milk street? Can you remember? No, I am sure it is not possible in europe these days. The light pollution is too hight. There is to much light in the night in the industrial areas of the world.

So our children will not see the milk street with their own eyes. They only can hear about it from their parents or be impressed of photos shot on satellits. The image on the left shows the light pollution of europe.