Welcome to TechScreen

Welcome to the TechScreen site. This side shall support the exchange of knowledge in the domain of Web Engineering and related aspects. As a side effect, this side is used for research on knowledge management technologies. User can pose challenges in the problem domain and can participate in quizzes. Further a bibliography about arcticles in different related domains is continously extended. Finally, questionnaires on different issues are provided. To be able to participate you need an account and a password from TU Wien's TISS system.

How to Aggregate the Tweets by User

Hot to Keep the connection open and gather the upcoming tweets, when using the Twitter API for mining Twitter Data with Python.

Control4 Driver Migration

Background: Control4 is a proprietary home automation system, installed at the customer by 3rd party installers. Devices (TVs, lighting systems, HVAC...) need drivers in order to be supported by the system. Many drivers are provided by Control4, others come from 3rd party companies. Installers can program devices using a simple graphical programming interface, depending on what operations the device driver offers (e.g. if switch_1 is pressed, set lights_TV to 50%). Our company was one of these 3rd parties writing drivers (i.e.

Wrong character encoding in XML file

After my Java code finished editing an XML file using JDOM2, the resulting project.xml has an incorrect encoding. Special characters (like italian "è") are not represented correctly, resulting in an unreadable character. XML Explorer (and sometimes even WinMerge) refuses to open the file.

For a long running process on a website, provide the user with live feedback

We have a webtool (written in Java EE, using log4j for logging) where users can upload files that are then processed and migrated to a new version, which users can download. Since this process can take quite a while and might fail, users should have live information about the process. Even in case of an overall success there might be errors the users should be informed about.

Fix Java OutOfMemoryError

Problem: For a university project I had to implement a simple Java application that uses the Twitter4J Java library for the Twitter API to collect data (tweets) based on different criteria and then analyze those data and generate statistics. For the data analysis I used the natural language processing toolkit developed by Stanford (called Stanford CoreNLP). The problem was, that the data were too large and when running the NLP algorithms I encountered the OutOfMemoryError. Solution: increase the heap size of the Java virtual machine JVM using the flags -Xmx and -Xms.

Test simple Java RESTful Web Service

Problem: for my bachelor thesis I developed a simple Java RESTful Web Service that could be used to control a mBot robot car using the internet. For this I used a Raspberry Pi to run the web service. The Raspberry Pi was connected via USB to the mBot. The embedded mBot controls (e.g. to move forwards/backwards, spin, retreive sensor informations) were called via the internet using HTTP endpoints.

Facebook Messenger on mobile phone without app

If you are not using Facebook on a regularar basis and / or you don't want to install the facebook apps on your phone, you can't access the facebook messenger via the mobile web version of the site. If you click the messenger, the site tells you to download the facebook messenger app. As I knew that it is working without an app on a desktop, I decided to try the option in the browser of the phone to show the desktop version of the webiste. Even though the navigation is not that comfortably as with the web version, you are able to access the facebook messenger.

Captcha bypass for faster access

Captcha (completely automated public Turing test to tell computers and humans apart) is a way to differntiate humans from computers. They are widley used on the internet to prevent a website from spam and bots. At a certain time during an ordering process for a sneaker, you needed to solve a captcha to get access to the plattform. Everyone needs to solve this capture and this takes up to 10 seconds. Exaclty this time can decide whether you are able to order the sneaker or not. Therefore I needed a way to bypass this captcha and gain an advantage over all other participants.

public WIFI with no internet access

There was a public WIFI with no password protection. Everone could connect to the WIFI, but there was no internet access, even tough they promoted it at the entrance of the restaurant. No employee was able to support, so I decided to connect to the router and try the standard login credentials. Usually they are user:admin pw:admin or blank password. This worked and I was able to restart the router. After the restart, the router could connect to the internet and everyone could access the web again.

Collaborate working with IntelliJ

Problem: Collaborate working with IntelliJ and Java: my colleagues and I used Java and the IntelliJ IDE for a university project (online voting system). To work together we decided to use git and had the issue, that by default the git Repository was filled with too much build data, because the .idea folder of the IntelliJ project, which contains project specific settings files and per-project details such as VCS mapping and run and debug configurations, as well as per-user details, such as currently open files, navigation history and currently selected configuration.


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