Display signal from OpenEEG EEG-SMT

September 10th, 2017

There is a number of software intended for EEG works. The EEG-SMT quick start guide suggests Electric Guru, BrainBay and OpenVibe, but it implies the use of a legacy operating system instead of Linux.

This post extends the quick start to have Linux notes. The content:

* Install OpenVIBE
* Connect STM-EEG to Linux
* Configure OpenVIBE
* Get the signal

Read the rest of this entry »

Affordable EEG and neurofeedback: OpenEEG, EEG-SMT

September 9th, 2017

My old interest is to influece the brain to make it working more efficient.

One of the approaches is to learn complete relaxation, or in other word meditation. The book “Meditation für Skeptiker” by Ulrich Ott suggests a scientific evidence for this claim, and I decided to try.

Read the rest of this entry »

Format dvd+rw before writing data

August 13th, 2017

Writing a DWD+RW under Linux should be simple, something like:

$ wodim speed=2 dev=/dev/sr0 -v -data ubuntu-16.04.3-desktop-i386.iso

However, in my case it fails. Some background knowledge suggests to format the disc first, but blanking the disc fails too.

Read the rest of this entry »

AWS response status is always 200

July 29th, 2017

There is a task, which can’t be avoided when developing serverless applicatoins on Amazon Web Services:

How to return a custom status code from a REST API?

One of the approaches is to use “prefix mapping”, like for example is shown in this amazon blog post: Error Handling Patterns in Amazon API Gateway and AWS Lambda by Bryan Liston.

The only problem is that the approach doesn’t always work. After a long debuggin session with many false tries, I’ve found the reason.

Read the rest of this entry »

mocking microservices for functional tests

February 4th, 2017

Here are a few links which helped me to understand what to use to mock microservices with REST API. Just for a case, I’ve choosen wiremock because I need Java and saboteur functionality.

Read the rest of this entry »

python Selenium in Ubuntu 16.04

December 22nd, 2016

Selenium is a web browser automation software. In Ubuntu 16.04 it doesn’t work out of the box, and external components should be installed. In this post I note how to install them locally without affecting the system.

Read the rest of this entry »

experience report with TDD

November 3rd, 2016

I’ve seriously tried TDD in a real project, writing tests before code and following the red-green-refactor cycle. Short summary:

* I believe in TDD now;
* training and practice are required to learn TDD, reading books is not enough;
* the initial time investment is big.

Read the rest of this entry »

how to move anything in rviz in ros

October 26th, 2016

Rviz A 3d visualization environment for robots. Sounds intriguing and useful, but the first steps in it are painful. In particular, moving anything is surprisingly a very hard task for a novice who doesn’t know about the right way. Now I have enough experience to describe what to do: Moving things in rviz.

vi editing mode set global

October 18th, 2016

The Linux command line and other software based on readline library support vi editing mode. After I worked on a new system with the default settings for a while, I noticed that I miss this mode very much.

Read the rest of this entry »

fast throw-away git repository

August 22nd, 2016

Based on the article How to Run Your Own Git Server, I’ve constructed a small list for fast git setup for temporary projects.

Read the rest of this entry »

DANTE e.V. Frühjahrstagung 2016

April 20th, 2016

I was a speaker at the TeX users meeting in Wuppertal, with the talk “Erfahrung und Vorhersagen für automatisches XML-nach-PDF-Publizieren mit TeX” (experience and prediction for automatical from-XML-to-PDF publishing using TeX).

Read the rest of this entry »

python libxml2 dita

January 21st, 2016

python libxml2 dita

For correct transformation of DITA files (XML-standard for modular documentation), it is necessary to pull information from DTD (document type definition). In my python code, sometimes I did get this information and sometimes not. Now I’ve tracked the source of instability and corrected the code.

Read the rest of this entry »

Printing unusually sized PDFs

December 21st, 2015

The PDF is of some non-standard landscape layout, the printer is an usual A4 printer, the software can’t handle the mix correctly. The solution is to tune the dimensions of the PDF pages manually.

Read the rest of this entry »

le-tex transpect: how to use docbook-to-docx stylehseets

December 10th, 2015

For XML to DocBook to .docx conversion, I found that “le-tex transpect” framework has solved many technical issues already, so I overcame the “not invented here syndrome” and decided to rely on this tool. To tune the stylesheets for own needs, I created a github copy of the repository: docxtools. To run the stylesheets outside the framework, a special setup is required. The setup is described in the folder “doc/hello-world“.

Generating Excel XML, avoiding “found unreadable content”

September 30th, 2015

In theory, changing content of an Excel file is easy:

* Parse XML from the zip-file
* Change XML
* Save XML into the zip

In practice I got the error: >>Von Excel wurde unlesbares Inhalt in … gefunden. Möchten Sie den Inhalt dieser Arbeitsmappe wiederherstellen?< < (English: "Excel found unreadable content...") Read the rest of this entry »

Tkinter sample application for a long operation

July 9th, 2015

In the year 2001 I started to experiment with GUI applications in Python. The experience was summarized and published in the article “A complete Python Tkinter sample application for a long operation“. Now, in the year 2015, a programmer have sent me an updated code. With the minimal changes, which mostly are update of the names of Tkinter modules, the code works.

Read the rest of this entry »

fast-disable css in firefox

April 17th, 2015

Sometimes I want to read a web page without its design “improvements”. In many case it is enough to switch off css, and in firefox this functionality is built-in. Shift+F7 to get the developer tools. Thanks stackoverflow for the hint.

Workaround for: CTR mode needs counter parameter, not IV

February 20th, 2015

After upgrading the local Linux system, my python paramiko (ssh protocol implementation) program stopped working, with the error message:

CTR mode needs counter parameter, not IV

Read the rest of this entry »

using freebidi from python using ctypes

December 8th, 2014

GNU FriBidi is an implementation of the Unicode Bidirectional Algorithm (bidi). There is a Python binding PyFribidi, but it is not complete. What I need is not a visual presentation of a string, but information where direction is changing. This function is not provided by the binding, therefore I’ve made an alternative using ctypes.

Read the rest of this entry »

certification 77-887 Microsoft Office Word 2010 Expert

October 6th, 2014

My advice: do use the “second shot” option. At least, I failed to pass the first attempt and had to try again. What was wrong:

* I needed time to adapt myself to the testing interface, and probably made something wrong in several first exercises.
* A few tasks are a bit unusual and I spent too much time on them. You should remember them and do homework.
* I work bad under under time pressure.

The best preparation resource I found is this youtube transcript: https://www.youtube.com/watch?v=7mm31GLUiNE. It is in French, but everything is clear, especially after the first certification attempt.

On the second attempt, passed. 918 out of 1000 is more than enough.