Day off and mobile internet

Disclaimer: That post should be published one day before, but it is today, due to unusual mobile posting problems.

I took one day off to enjoy summer in beautiful nature surroundings.
Being in possession of cell phone with some smartphone possibilities, I have decided to try out mobile internet.

Few days ago, I have turned on gprs service at my cell provider. Everyday I have been surrounded by computers, almost all connected online.

What for do i need internet on my cell? One reason are convenient online services kille weather or dining searching. The other explanation is that I am computer/internet addict.
I have tried some useful software on my nokia s40 phone.
Here is my list:
Opera mini - good for search and news browsing
Gmail mobile - explanation is not needed
Midpssh - nice ssh client - for use in critical situations
Some IM ,SIP VOIP client - still searching
The real pain is text input. It would be nice to use better method than T9

Enough. I am going for a walk

Analysing SleepTracker data for R.E.M. phases

I'm collecting sleep data from my Sleeptracker watch for above 3 months. It's a good time to check what is interesting in there. My goal is to check pattern of my sleep R.E.M. phases.

First, I get my sleep data in csv format stored on www.sleeptracker.net site. Then using simple python script I've converted all night/time data into relative values. Now I have all SleepTracker movement occurrence time saved in "hours after going sleep".

After looking at initial data I was a little bit disappointed. I have not seen clean gaps for non R.E.M phases. Picture was so cluttered. There were many possible reasons. I've choosen one - sometimes I go sleep at different time, but sleep patterns may be anchored to usual hours.

I decided to make more preprocessing to move out "outstanding" data. I removed data instances with non standard "going to bed" times, movements it the first hour of sleep and some made some minor tweakings. When I viewed data again the picture was much clearer.



I rerun data clustering software using standard kmeans method and get some results:

Cluster 1
Mean/Mode: 0.8458
Std Devs: 0.2783

Cluster 2
Mean/Mode: 1.5433
Std Devs: 0.2069

Cluster 3
Mean/Mode: 2.6117
Std Devs: 0.2857

Cluster 4
Mean/Mode: 3.6685
Std Devs: 0.236

Cluster 5
Mean/Mode: 4.8086
Std Devs: 0.2848

Cluster 6
Mean/Mode: 5.9405
Std Devs: 0.4276


That means that probably REM phases occurs about 0.85, 1.5, 2.6, 3.6, 4.8 and 5.9 hours after falling asleep. Common value found in literature is about 1.5 hour between R.E.M. phases.
Bigger standard deviation in later vs earlier phases reflects longer R.E.M. phases at each cycle, what is also found in sleep research. First cycle must be treated in special way - the sleep pattern is different sudden after falling asleep.
The last one can be also less reliable because of standard waking time after about 6 hours.

I decided to pick R.E.M. time values by my self using "smoothed" histogram of sleep data. Local modalities are clearly visible on picture.


Now middle of phase values seems like: 0.8, 1.6 , 2.3 , 2.8, 3.4 , 4 , 4.9. Comparing these results with those from automatic clustering method it seems that "k means" method joined 2 close groups together.
I assume that manually picked results are better.

Time for conclusion.

To get more reliable results I need more data and regular sleep :) . SleepTracker is quite effective by using simple accelerometer movement detection method. Unfortunately many movement events aren't recorded (for example the subtle ones or when the arm is blocked under the pillow). I will try to catch more good data and check results again.

Summer is coming

It's really hot for last few days - real summer weather. I'm often going out for outdoor activities.

I'm finishing production stage of one of bigger projects I'm working now. I'm thinking about summer time and resting in some nice place.

Price of gas is arising, but I'm planning only one long distance trip. For other destinations I'm going to visit some places near by, maybe do some biking.

Anyway- my home computer is more turned off, and my new projects are going on the shelf for some time.

PyCha chart drawing library working under SPING

I've ported PyCha chart drawing library to work under SPING instead of Cairo. I've discussed that idea with PyCha lead developer - Lorenzo Gil Sanchez.

Lorenzo said he will still stick with Cairo, that is good library ported and available for many systems. Anyway I've ported PyCha to SPING and tested with SPING creating SpingCha off-project.


Here is lastly created PyCha news group , where you can find posts about PyCha development.
And - if anyone is interested - working SpingCha release in files section.