Dil's Domain

 This error occurred when I was trying to run a .py to plot my graphs using matplotlib for the research. I was able to plot graphs well before this happened. However it wasted my precious few hours dedicated to research work so I want to spare your time and thought of writing how I solved... When I googled the error it said that it was an error in .pyc files but was not specific. I tried the given solutions like reinstalling python. (not reinstalling OS which was given as solution too since uninstalling python would cause OS errors) The method I tried to remove .pyc files -> here The error again was -> Traceback (most recent call last):   File "2m.py", line 2, in <module>     import matplotlib.pyplot as plt   File "/usr/lib/pymodules/python2.7/matplotlib/__init__.py", line 123, in <module>     import pyparsing ValueError: bad marshal data (string ref out of range) Then I tried installing pyparsing which was alr...

Towards the end of the internship as our lab celebrated its 10 th anniversary, there was a suggestion to start translation of English wikipedia pages to Sinhala, the commonly used language in Sri Lanka. This would be a great help to break the language barrier of young new comers who like to learn technology. Here are the simple steps to start translation. Create an account in wikipedia ( Create Account ) Then you can log in and start  (Get Started ) From Beta features , you can select "Content Translation" Select a page you want to translate from here . Select an input keyboard. (I used the singlish keyboard and the Wijesekara key board) After translating, publish your translated article. This was a very interesting activity to me, since the article I started with required a lot of thinking of real meaning to translate. We also get support from the Natural Language Processing lab in our university. I hope to do this often as a hobby to open gate...

Towards the end of our internship period we started writing research papers based on our work. We used LaTeX to write. LaTeX Use this command to install LaTeX, sudo apt-get install texlive-full Then download a template and go to the relevant folder and type ' make ' and enter. This will run the Makefile. The .pdf file will automatically get generated based on the .tex. The .tex can be edited with 'gedit .tex' or 'gedit .tex &' SVN Apache Subversion (often abbreviated SVN , after the command name svn ) is a software versioning and revision control system distributed as free software under the Apache License. We use Subversion to maintain current and historical versions of files.  To install svn, sudo apt-get install subversion Then choose the location, eg: cd home To get the current version of the repo,by login to server, svn co svn+ssh:// uname@192.248.22. 131/var/svn/name/ Editing of files can be done with following tw...

While working to identify the frequency my android phone uses, here are some important links and apps I came across. This is an app I used to find out the LAC (Location Area Code) and CID() https://github.com/SecUpwN/Android-IMSI-Catcher-Detector The following information and more can be taken form the above app: MCC — a Mobile Country Code. This code identifies the country. Sri Lanka- 413 MNC - a Mobile Network Code. This code identifies the mobile operator. eg: Dialog-2, CellTel(Etisalat)-3 LAC - Location Area Code is a unique number of current location area. A location area is a set of base stations that are grouped together to optimize signalling. eg: 20126, 3003 CellID (CID) — is a generally unique number used to identify each Base transceiver station (BTS) or sector of a BTS within a Location area code. eg: 1702739, This is the link I used to find how to track the BTS with Cell ID and LAC: http://cellidfinder.com/articles/how-to-find-cellid-location-with-mcc...

This article has some useful commands I came across while doing the research lab work. To remotely login into a virtual machine,  creating a user group, and giving permission to the group to access that folder. This is done by changing the group ownership of the directory. Remotely log in to the virtual machine ssh username@[ip] Login from user account and goto the root terminal. su root Creating a group sudo addgroup groupname Creating a user into this group sudo adduser username groupname View all groups groups cat etc/group Change owner and group of a file or directory chown {-R} [user]{:group} [file|directory] Change folder permission only of a group(not user) chgrp {-R} [group] [file|directory] Change permission(read write execute of directory ProjectData to the group and user) cat /etc/group chmod 770 ProjectData

This post is realted to my previous post , where the tools that should be pre installed are mentioned. Gqrx which is preinstalled in the live DVD can be used to visualize the frequencies. Here are examples of gqrx  tuned to different frequencies observed from channels captured from hackrf_kalibrate. (see my earlier post) Tuned to frequency 950.8MHz. Tuned to 959.6MHz. Then we need to run the grc script airprobe_rtlsdr.grc which is located at gr-gsm/apps folder found in the pre installed gr-gsm. Here is a screen shot of the flowgraph. I set the default value of gain to 40, which increases the packets captured from wireshark which is later explained. Here is a screen shot when I run the flow graph. Then we have to run wireshark from another terminal. Interface is loopback interface (lo). Use the following command, which runs wireshark as root user with icmp and gsmtap filters. sudo wireshark -k -Y 'gsmtap && !icmp' -i lo Here is a sc...

The GNURadio version used for this is 3.7.9. I used the live DVD image which can be downloaded from here. The extra tools needed are : hackrf_kalibrate gr-gsm gqrx  wireshark (gqrx was preinstalled in the GNURadio image). This is how I installed the other three tools. Installing gr-gsm ,  GnuRadio blocks which is used to decode GSM packets . sudo apt-get install git cmake libboost-all-dev libcppunit-dev swig doxygen liblog4cpp5-dev python-scipy git clone https://github.com/ptrkrysik/gr-gsm.git cd gr-gsm mkdir build cd build cmake .. make sudo make install sudo ldconfig I had the error "package 'libosmocore' not found", so I had to manually install that package using the commands provided in this site. cd libosmocore/ autoreconf -i ./configure make sudo make install sudo ldconfig -i cd .. And during the configuration  "No package 'talloc' found" error occurred and I had to download and install it manually with this link. ...