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.

Replace missing value with median of attribute for the corresponding class

There exist several strategies to overcome missing values in machine learning, like ignoring and replacing the missing value with a logical replacement. One very challenging, but extra rewarding strategy is to replace the value with the median of the attribute for the corresponding class. So given an attribute that has missing values, and obviously has a class outcome, you have to calculate the median for each class and replace it for the corresponding class in the selected attribute column.

TPLink Powerline Adapter loosing connection

The TPLink Powerline Adapters occasionally loose their network connection and you have to disable and reenable the network-card of the computer to get it working again. A solution is needed to fix this network connection loss, as it makes these Powerline Adapters unreliable.

Creating a Custom WorkItemHandler in jBPM for Eclipse

I had to create a custom WorkItemHandler for jBPM in Eclipse to execute my own code when reaching a specific node in a Business Process, since a ScriptTask (which allows to execute code) was not enough because it does not allow to manipulate Process variables. A custom WorkItemHandler would also allow for better maintainability of the Business Process because it does not depend on scripts hidden in the process definition, but is directly visible in its own java class.

Manipulating machine learning datasets in VS .net

As a task for a Business Intelligence exercise I was looking for a simple C#-library to read/write/manipulate Weka attribute-relation file format (ARFF) files. The library should ideally already be pulished in the official NuGet Gallery repository to simply be used within Visual Studio 15 and the integrated NuGet-package manager.

Wake on LAN not working under Windows 10

After upgrading from Windows 7 to Windows 10, wake on LAN does not work anymore.

Spotify always opens on primary screen

I have Spotify premium, using the desktop application. On my computer I have two monitors, the second is dedicated for additional programms, such as my music player. When I logon my Computer, the app always starts on my main window, blocking all my view. This occures, when I start "cold", restart and after hibernating.

Pass value from one Android activity to another

Since two activities have no shared space (by default), it is not possible to grab that value/variable from the original activity. One has to not only find a way to store this value in the original activity, but find a way to access it from the newly created activity. This allows data sharing between activities to some extent. The value has to accessible at activity initialization as well as at any other point in activity life-cycle.

Efficiently use font icons on web pages

In order to have a webpage with content other than text, it should also be possible to add icons that are stored as a font file. A web designer and content provider would like to use them as vector graphics so that quality is not lost when zooming/printing a document. In order to do that they need a way to reference a single icon and be able to manipulate it as a DOM object (e.g. hide, change style, animate,...). Important restriction is that all icons should stay in one file, which requires user to make only one request to the server (to download a single file).

Automatically start and log into VPN on Windows Startup

To connect to a VPN with Windows, after you have acquired VPN access (either commercially or a free one) you generally might want to use it/log into it. This means every time the VPN should be used a login into some third-party software or some handling of the Windows integrated software is necessary (i.e. choosing connection, inputting username/password). This challenge is to present a solution so that the computer automatically does this process for you on startup.

Installing an image from a PC with ide drivers to a PC with (only) ahci drivers available

To save time with installing several programms an image was made form an old PC. That PC was using ide drivers for the harddrive. The problem was, that on the new machine, only ahci mode was available in BIOS, so that there was no possibility to boot. In normal cases you would change the entry in the registry before changing the BIOS Settings from ide to ahci.


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