Archive for category My job

Video distribution in the classroom

We have a computer room in our local university, ind it’s quite bussy. The main problem it became (this is another story) too long to be usable and there was a strong demand for the screencast view right on the student’s workplace. Yes we do use beamers, but the view was too small to dead the text on the screen.

And so the project was born. There is single seat where the view originates and multiple locations where it should be visible. The system must be easily expandable and upgradeable, no vendor lock-ins. All the points in the systems should be easily adjustable and replaceable.

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Small problem with CFD simulations

Just a tiny hole in the mesh may create a great mess.

The initial wind speed is 10 m/s, laminar aiflow. And the result is small F15+ class tornado int he Fujita scale.

Messing with PHP-ODT

I’m working oh hobby project on a free time, and one of the tasks here is to generate ODT file, containing output from the database. The output library i’ve chosen is PHP-ODT. It’s kind of basic, but allows to create ODT documents on the fly.

And now, lessons learned

Allways provide file size.

This code will create corrupt file, according to LibreOffice: The correct code is:

 header(“Content-Description: File Transfer”);
header(“Content-Type: application/vnd.oasis.opendocument.text”);
header(“Content-Disposition: attachment; filename=\”” . $ODTFile .”\”” );
readfile($ODTtmpFile);

 header(“Content-Description: File Transfer”);
header(“Content-Type: application/vnd.oasis.opendocument.text”);
header(‘Content-Length: ‘ . filesize($ODTtmpFile));
header(“Content-Disposition: attachment; filename=\”” . $ODTFile .”\”” );
readfile($ODTtmpFile);

It is possible to add hierarchical styles

Not in the base code yet

$pStyleDate = new ParagraphStyle(‘revDate’);

$pStyleDateStrike = new ParagraphStyle(‘revDate-strike’);
$pStyleDateStrike->setAsChild(‘revDate’);

It is possible to add text decorations in the paragraph level

Again, not in the base code yet:

$pStyleDateStrike->setLineThrough(StyleConstants::SINGLE);

It is possible to merge cells in the table

Well, not in the base code and horizontally only:

$hSpan=array(“”,””,””);

$cRow = array($hSpan,$pRev,$pDate,$pMemo);
$table->addRows(array($cRow));

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The Power of Pipes

Okay guys, the log if filling with

sshd[20117]: Invalid user pi from 142.93.118.186 port 50416
sshd[20117]: input_userauth_request: invalid user pi [preauth]
sshd[20117]: Received disconnect from 142.93.118.186 port 50416:11: Bye Bye [preauth]
sshd[20117]: Disconnected from 142.93.118.186 port 50416 [preauth]
sshd[20119]: Invalid user cubie from 5.189.227.161 port 39772
sshd[20119]: input_userauth_request: invalid user cubie [preauth]
sshd[20119]: Received disconnect from 5.189.227.161 port 39772:11: Bye Bye [preauth]
sshd[20119]: Disconnected from 5.189.227.161 port 39772 [preauth]
sshd[20121]: Invalid user guest from 208.68.37.169 port 42858

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Postfix and virtual SMTP users

Short how-to use the save virtual users both for receiving emails via IMAPS, and sending via SMTP, or just rants for myself:

Source for the ideas and setup

/etc/postfix/main.cf must contain:
smtpd_sasl_local_domain =
smtpd_sasl_auth_enable = yes

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Woodpecker 2.8 GRBL board and ISP connector

In the case you heed to to upgrade the Woodpecker CNC control board, you will have to overcome some issues.

First one, the firmware upgrade via USB is almost(?) impossible, due to the CH340 chip between USB socket and Atmeg328.

Second one, the ISP header IS present on the PCB, but is has 1,27mm (0,05″ or 50 mils) pitch. Usual ISP connectors comes to 2,54 mm (0,1″ or 100 mils) pitch. Read the rest of this entry »

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My GRBL settings for 3018 CNC DIY machine

My settings for 3018 DIY CNC machine with Woodpecker’s control board and GRBL 0.9j.20150930. Note the feed rate and acceleration on axes.

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Rant on Apache2

Recently I was trying to move my sites to SSL – for various reasons.
The test site went fluently, while the work machine refused to serve SSL content. While testing with ‘wget’, the error I received was

GnuTLS: An unexpected TLS packet was received.

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Meet the fMRI Parrot

fMRI Parrot

Camera
LG-D405n
Focal Length
3.2mm
Aperture
f/2.4
Exposure
1/20s
ISO
600

What the heck is “fMRI Parrot”?

First of all, the heck is fMRI. fMRI stands for “Functional Magnetic Resonace Imaging”, as defined in Wikipedia. It involves tons of expensive hardware, like Magnetic Resonance machine, and software, used to reconstruct the scanned volumes. During fMRI scanning a series of stimulus are applied to the patient and the brain is scanned using fast scanning MRI techniques. The aim of fMRI is to record immediate changes happening in particular areas of the brain.

The single MRI scan is called “volume”. It is created from a series of slices of the predefined thickness. Having more slices creates more detailed volume and extends acquisition time. As the changes of the brain activity are momentary, a short volume acquisition interval, named TR or “Time Repetition” is needed. Usually it varies from 7 to 1.5 seconds, depending on the capabilities of the MR machine. Short TR time supposes lower quality scans, compared to the “traditional” MR scanning. So the level of detail of particular volume is a trade off between time and specific requirements.

The fMRI scans consists from a number of volumes, recorded at particular intervals. The key condition for a successful scan is the precise timing. In order to find a region with elevated activity, a stimulus must be started just when the volume acquisition begins. For this the MRI machine may expose a short pulse – start of a volume. The pulse may be brought to the MRI control room via the interface box and the required stimulus started automatically. Some stimulus require the patient to respond, eg. press the predefined button. The response from the patient is also brought to the MRI control room. As there are special requirements for any hardware at the MRI machine, only certified equipment is allowed to the MR room. The requirement at the MRI control room are more relaxed as well as the choice of the equipment There are different vendors of the interface boxes and response buttons, NordicNeuroLab (NNL) being one of them.

In order to create the simulation series, or paradigmas in fMRI terminology, a lot of time is needed. Each paradigma is to be verified before the clinical test, while some of them can not be tested without a signal form the MRI scanner or a response from the patient. There is no need to say the MRI equipment is expensive, so is the time spent in the MRI machine. Most of the MRI scanner interface boxed can be used in so called “simulation” mode, sending particular responses at the predefined moments, without actually running the scanner. For example the Sync Box from NordicNeuroLab will send “S” symbol at the start of the volume acquisition, while fORP from Cambridge Reserch Systems is to send “5”. So what is actually required to test a paradigma, is the response from the scan… WAIT!

It’s must not be the MRI scanner nor the interface box.

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On the door handiness in Autodesk Revit

I was working on semi – automated solution to enter door handiness in Revit models. The existing solutions are either quite expensive (like Reforma Swing Direction) or has weird assumptions.

My intial setup is Dynamo and the Dynamo Door Set Handing module from http://archi-lab.net/. It has fine tutorials, so you only need to create your model in Dynamo.

The weird thing on door handines is it is different in some countries.

  • Door handiness in Germany is defined as hinge position on the door, when one is pulling the door to open. if the hinges are on the left side, the door is left-handed, and if the hinges are on the right side, the door is right-handed. I will refer it ad “DIN – style”.
  • The IFC, together with ISO 16739 defines door handiness as the position of “positive Y axis”, which is definitelly the position of door handle when puling.  I will refer it as “ISO – style”.
  • Americans use ISO style, but also has “reversed” option. I still have no idea on this option, as “reversed right” is “left”.

So, what’s to do?

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