European expertise in computational logic is diffused over a wide geographical area including most of the main European countries and regions. Likewise, computational logic applications are spread through a wide range of industries and markets.

The new CL Portal aims at providing the official gateway to all information connected to computational logic, as the catalyst for a growing CL community, industry, and present and future students of computer science. Our vision is global – connecting the world to comprehensive and up-to-date CL information and services.

Here, you can find the latest information on:

  • Research Areas
  • Events
  • Education
  • Jobs and Grants
  • Repository
  • Journals

Below, you can read more about the technology used on this portal.


It’s a well-known fact that the most important part of each web page is its content. The content part of the CL Portal consists mostly of dynamically generated sections. Those sections are being automatically extracted, integrated, and represented with support of the latest web mining technology. Below, you can read more about this technology.

Lixto Visual Wrappers and Transformation Server

Data displayed in all of the dynamically generated sections is collected automatically from the research areas’ web pages, and a wide range of other carefully selected web sources converted into a structured form and integrated into one dataset.

Each section has its own database, which is updated regularly according to sections’ settings. For example, the “Repository” items “Systems” and “Publications” are updated twice a month, and the “Events/News” section is updated every two hours. There is also a possibility to update a section on request, e.g. if a person should be added into the “People” submenu of the “Repository” or a research area has an important announcement to make, and does not wish to wait for the next automated update cycle.


The automated data extraction process was accomplished with wrappers created by the LiXto Visual wrapper. Each wrapper is designed to transform a set of HTML pages into structured XML data. While working with Lixto Visual Wrapper, an operator generates a wrapper program which converts relevant information from HTML to XML. Lixto Visual Wrapper generates a so-called XML companion for given Web pages.

The transformation of the extracted data (see fig. 2.) was performed by the “Transformer” object of the LiXto Transformation server. For the CL Portal, the data from a number of pre-defined sources were stored into one database. Data integration process was subsequently performed by the “Integrator” object of the Transformation server.

A special data cleaning module — the “Cleaner” — was created to perform data cleaning. While performing this operation, the “Cleaner” checked validity of database entries for the duplicate items and removed them. This way, it was ensured that no information represented on the main CL Portal was redundant in any way, and that it conformed to the original editing policy imposed by CologNET‘s Consortium sponsoring the Portal.