Category Archives: journal

The Doctor wanted more data? Well, here it is!

The challenge

Back in… what? 2006,  I went to the doctor for a routine checkup, he was concerned that my blood pressure might look a tad bit high. He continued to explain sometimes the stress of going to the doctor’s office might artificially increase your blood pressure, and I should go to a pharmacy where you can get your blood pressure measured for free.

The experiment

Well, I decided why not one-up that idea and buy a cheap personal blood pressure/heart rate monitor? I recorded my heart rate and blood pressure almost every day for about a year, sometimes more than once a day. I know, they say you should make these measurements all at the same time, usually just after waking up, but I… got lazy ok? As a side note, I got very little exercise over this period, I’m curious how these plots will look now, since I exercise pretty much every day.

Heart rate over 1 year of measurements (2006), not taken at the same time every day.

The time series of my heart rate (above) seems noisy. Let’s have a look at the histogram of that:

Histogram of heart rate for 2006 (180 measurements). Looks like a Ricean distribution with mean~=64 bpm

Mean of 64 bpm? That is definitely not cool. I’ll have to start taking some data for 2010 and hope that exercising 5+ times a week brought that average down!

Let’s have a look at blood pressure. Below is a time series of both systolic and diastolic blood pressure:

Time series for SYStolic and DIAstolic blood pressure for 2006

We can look at the distribution for both these measurements as well:

Systolic blood pressure distribution appears quite gaussian with a mean of 133

Diastolic blood pressure distribution for 2006. Mean is 79

So over a 1 year average, my blood pressure was 133/79 and average heart rate 64 bpm. It’s not horrible, but something like 120/80 with a heart rate of, say, 50, would be way cooler. Perhaps that is the goal for 2010?

Instrument Calibration

Getting back to the original story line, I showed these graphs to the doctor. Needless to say, he was not impressed. I insisted that this data needs to be traceable back to a ‘national standard’, so to speak. So the doctor used his standard-issue blood pressure device, while 10 minutes later I used my electronic gadget to make (hopefully) the same measurement. It turns out the Doctor’s device was always about 10 points below mine. He decided to use this one measurement to refute all my data: obviously my device is wrong.

After he made his one measurement, he declared that my blood pressure is fine and there’s nothing to worry about. Bah.

Tamale Fridays greet you, I’m not even supposed to be here!

Sitting in my favourite coffee shop, drinking my favourite drink, ready to update this blag, I realised that I left the crucial data at home that I wanted to write about today. So… it will just have to wait. Today is my ‘day off’, which means I go in to work, blast my music (because nobody is there) and get a lot of work done – it’s great.

Although… I was so excited about life last night that I couldn’t really sleep. You see, the problem was that I got back from work at 23:00 (11pm for you yankees) – arriving at my apartment in Old Town Pasadena on bike (yep, still biking to work), I was hot, sweaty, and definitely not ready for bed. To make matters worse, at 01:00 when I tried to sleep, I started getting hungry! So, a midnight snack and ice cream cured that and finally saw me off to bed around 02:00. I feel like the clerk in, well, Clerks: I’m not even supposed to be here! I knew if I slept in today, my whole sleep schedule would be deranged, so here I am, going to work, and not even supposed to be here.

Work is fun though, and since a post with only text is quite boring, here is a picture of my office. Oh yes, we had a 8+ hour power outage at JPL on Monday from 14:00 onwards, I took the time to rearrange my office and build this awesome command center:

Command Center at work: 30" apple cinema display accompanied by two 24" cinema displays.

Command Center at work: 30" apple cinema display accompanied by two 24" cinema displays.

It’s hard going home to my puny 27″ display after spending a few hours at the command center!

Lazy Sunday

Ah yes, I’m spending my Sunday finally organizing my photo collection. I have photos from 1999-2009, with a HUGE gap from 2006-2009. You see, my digital camera broke. Various trips are still documented via my (shitty) iPhone camera and other friends’ cameras. I’ll slowly get my picasaweb up to date again:


A few friends were in town from Colorado and Michigan for Halloween, we decided to make a big night out of it and attend a Bel Air (mansion) house party. As we pulled up in our van (with no back seats), holding about 10 people cleverly clad in costumes appropriate for such a night, a few things became apparent:

  • The house (mansion) had two gentlemen to valet our van
  • The house (mansion) was really a mansion
  • Did I say Bel Air?
  • The front entrance of the mansion included two dance poles
  • They had a bar with 3 or 4 bartenders at any given time… and it was OPEN. I mean, seriously, who has an open bar at a house party with 100+ guests?

What type of halloween party did we just walk into? Well, one that had the promise to totally rock our worlds. 


See the dancing poles in the back?

See the dancing poles in the back?



More random people (see me in the white hat & fro?) I met at Halloween.

More random people (see me in the white hat & fro?) I met at Halloween.


Not your average party (at least, not mine!)