Guest Editorial: Special Section: Papers selected from the 8th Balkan Conference in Informatics (BCI 2017)

This special section consists of substantially extended and revised papers from the 8th Balkan Conference in Informatics held in Skopje, Former Yugoslav Republic of Macedonia, 21-23 September 2017. Six best papers were initially selected from the 27 papers presented at the conference. Three of them were finally included in this special section, after passing through a rigorous reviewing procedure.

In the first paper, entitled "Using Screencasts to Enhance Coding Skills: the case of Logic Programming", Petros Kefalas and Ioanna Stamatopoulou discuss the use of screencasts as a pedagogical tool for creating visual learning materials. The educational roles of screencasts are presented, together with a selection of tips and techniques that can be applied in screencast production. Examples of how screencasts can facilitate learning in programming courses are included, with a special focus on Logic Programming. The proposed approach for teaching Prolog is evaluated through an experimental study, with positive results regarding students' understanding and motivation.

In the second paper, entitled “Learning Syntactic Tagging of Macedonian Language”, Martin Bonchanoski and Katerina Zdravkova propose a Part-of-Speech (PoS) tagging system for Macedonian. They trained four well-known PoS tagger systems implemented for English and Slavic languages, i.e. TnT, cyclic dependency network, guided learning framework for bidirectional sequence classification, and dynamic features induction. They manually tagged Orwell’s novel “1984”, and split it into training and testing sets. The resulting PoS tagger system, freely available online, has an accuracy of 97.5%, which makes it appropriate for the future grammatical tagging of the developing National Corpus of Macedonian language.

In the third paper, “Definition and Enforcement of Complex Integrity Constraint Types in XML Data Model”, Jovana Vidaković, Sonja Ristić, Slavica Kordić and Ivan Luković propose definitions and enforcement for complex integrity constraint types in XML. Integrity constraints are mechanisms for ensuring data consistency, a very important aspect of data quality. There are integrity constraint types, such as key constraint, unique constraint and foreign key constraint, that are supported in most DBMSs. Other, more complex constraint types are difficult to express and enforce within a data model. They are almost completely disregarded by actual DBMSs and the users have to manage them using custom procedures or triggers. eXtended Markup Language (XML) has become a universal format for representing and exchanging data. In this paper, the authors present a classification of constraint types in relational data model, discuss possible declarative mechanisms for their specification and enforcement in XML data model, and illustrate the proposed approach to the definition and enforcement of complex constraint types in XML data model on the example of extended tuple constraint type.

Acknowledgement

We are grateful to the Editor-in-Chief, Prof. Mirjana Ivanović, for giving us the opportunity to guest edit this special section and for her support and guidance. We would also like to thank the following reviewers for helping authors to improve their papers, through their timely and valuable feedback:

Ankica Barišić (Universidade Nova de Lisboa, Portugal)

Costin Bădică (University of Craiova, Romania)

Mihaela Colhon (University of Craiova, Romania)

Marius Gavrilescu (“Gheorghe Asachi” Technical University of Iași, Romania)

Marko Hölbl (University of Maribor, Slovenia)

Ladislav Huraj (University of SS. Cyril and Methodius in Trnava, Slovakia)

Malinka Ivanova (TU Sofia, Bulgaria)

Geylani Kardas (Ege University International Computer Institute, Turkey)

Aleksandra Klasnja Milicevic (University of Novi Sad, Serbia)

Zuzana Kubincova (Comenius University Bratislava, Slovakia)

Mart Laanpere (Tallinn University, Estonia)

Fernando Moreira (OPorto Global University, Portugal)

Oscar Romero (Universitat Politècnica de Catalunya, BarcelonaTech, Spain)

Hamman Samuel (University of Alberta, Canada)

Guest Editors

Elvira Popescu
University of Craiova, Romania

Florin Leon
“Gheorghe Asachi” Technical University of Iași, Romania

Boris Delibašić
University of Belgrade, Serbia