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 erase data in Apache Jena Fuseki

My problem is following: I created a new dataset with the name A in Apache Jena Fuseki, uploaded data B and erased dataset. I created a new dataset A and uploaded different data C. Why the original data B is still visible in the newly created dataset?

How to stop pop-ups in chrome

Many times when we try to find something on the internet using Chrome we find the problem of pop-ups. Trying to perform a search with pop-up windows showing up is annoying and makes searching difficult.

Access a website with a recent DNS change on Windows

Pointing a domain to a new location might turn out to be a problem, because most operating systems keep a DNS cache to speed up the resolution of frequently visited sites. If the location changes before the DNS cache is updated the web server is no longer accessible until the cache is updated again.

Executing tasks regularly in a Django web application

Some web applications periodically need to perform some sort of task (retrieve data from a remote location, perform data store cleanup, etc.). Sometimes these tasks would take too long for a regular request and the user should not have to wait until the task completes.

Trying to fit the screen in CSS

In a web application I am developing, I had a CSS design problem. I had a title bar on top and underneath I had the content. I needed to get the content to spread itself to fit the whole screen instead of squeezing itself to the top.

Improving usability of input forms in web applications

In the web application I am developing, I had a barcode input text field and a URL input text field for two different functions of the application. This resulted in 4 text input fields and 4 submit buttons. The layout of the web page became confusing for new users and clattered. I needed to reduce input fields in the front end but also in the already implemented back end.

SPARQL group by only one variable

In semantic web, sparql is a powerful language which can among others query for specific knowledge from provided rdf databases. Recently I tried to find out the largest lake in each country in the world from dbpedia. I came up with a query which resulted in the country and the area of its largest lake but without the name of the lake. I wanted to list the name of the lake in the table.

Customizing WordPress themes without losing changes on updates

The layout and appearance of a WordPress blog is determined by its theme. Most themes offer various options to customize its looks, but often some additional coding is required to create your desired design. If the theme files are modified directly, all modifications will be gone when the theme is updated. A more durable solution is desirable.

Custom charset encoding in filenames when using FTP

FTP is often used to transfer files from one server to another or to create a backup of a website. In most cases, copying all the required files works just fine. Problems might occur though, if some of the filenames use an unexpected charset encoding. When downloading and re-uploading such a file, the filename will be broken and the website won’t be able to serve it anymore. How can you ensure, to always download files with their correct charset encoding?

Moving a WordPress site to HTTPS

An existing WordPress site shall be moved from HTTP to HTTPS. All resources should be loaded via HTTPS after the update. Therefore, all text occurrences, hyperlinks and image resources in pages and posts must be updated with the new URL.

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