Emília Pietriková

A Task-driven Grammar Refactoring Algorithm

This paper presents our proposal and the implementation of an algorithm for automated refactoring of context-free grammars. Rather than operating under some domain-specific task, in our approach refactoring is perfomed on the basis of a refactoring task defined by its user. The algorithm and the corresponding refactoring system are called mARTINICA. mARTINICA is able to refactor grammars of arbitrary size and structural complexity. However, the computation time needed to perform a refactoring task with the desired outcome is highly dependent on the size of the grammar. Until now, we have successfully performed refactoring tasks on small and medium-size grammars of Pascal-like languages and parts of the Algol-60 programming language grammar. This paper also briefly introduces the reader to processes occurring in grammar refactoring, a method for describing desired properties that a refactored grammar should fulfill, and there is a discussion of the overall significance of grammar refactoring.

Genetic evolution of programs

We present evolutionary approach to program development based on absorption of genetic strings at different metalevels. Introducing the principles of software evolution as processes of semantical stability, expansion and contraction, we continue with an example illustrating how it is possible to integrate metalevel with base level and how this integrated computation works when driven by genetic string of codons, determining decisions for program construction and the result of constructed program execution. Next, we analyse the evolutionary circle at metalevel and we show that mentioned expansion and contraction is possible. The main contribution of the paper is that it breaks classic boundaries between models and programs because formal binding of metalevels and base level have been reached.

Useful recommendations for successful implementation of programming courses

Learn to program is hard. Learn to program well, is harder. But much more challenging is to teach students how to program. According to this fact, programming courses may become boring. But if we try to motivate students enough (and games provide an excellent motivation), teaching and learning programming can provide an entertaining experience. This work is focused on advices for programming teaching that have played out in global results of programming courses in a university of Central Europe. The results include game-based learning in combination with learning by game creation, supported by case-study approach.

Towards Automated Program Abstraction and Language Enrichment

This paper focuses on the presentation of a method for automated raise of programming language abstraction level. The base concept for the approach is a code pattern -- recurring structure in program code. In contrast to design patterns it has a specific representation at a code level and thus can be parameterized and replaced by a new language element. In the article two algorithms for automated recognition of patterns in samples of programs are described and examined. The paper also presents an approach for language extension based on the found patterns. It is based on an interactive communication with the programming environment, where recognized patterns are suggested to a programmer and can be injected into the language in a form of new elements. Conducted experiments are evaluated in regard to the future perspective and contributions.

Haskell clone detection using pattern comparing algorithm

Detection of clones - repeating fragments in source code - is an important task for ensuring maintainability of software systems. This paper presents an algorithm for clone detection based on comparing parts of abstract syntax tree of programs and finding repeating patterns. The algorithm is implemented in the prototype tool that allows to detect clones in programs written in Haskell programming language. The main contribution is believed to be proposal and experimental verification of the new technique for identifying exact and syntactical clones in Haskell code.

Profile-driven source code exploration

The following study deals with static analysis of Java source codes and it is dedicated to those readers who are interested in techniques aiming at evaluation of programming abilities of job candidates or students. In our case, the goal of the static analysis is to assemble the most significant and interesting data about source code author (programmer). If properly visualized, such assembled data may form programmers profile which, to impartial observer, may further determine authors real programming abilities and his/her habits, both good and the bad ones. The present study represents first experiments attempting to form programmers profile by static analysis of language element frequency. Conclusion offers a broader view, combining also other techniques as a future plan to generate knowledge profiles more precisely.

Towards automated assessment in game-creative programming courses

This work describes an environment supporting learning by creating computer games in programming courses. The environment consists of guidelines for student assignments (instructions for computer game creation - the key motivator). In order to submit assignments regularly, the environment is connected to Git version control system. Moreover, assignments are regularly assessed by the platform called Arena. The aim is to provide feedback as soon as possible, so there is enough space for bug fixing and personal improvement. In addition to ongoing assessment, Arena provides a web interface for writing code and displaying test results immediately, which is used mainly during exams. The main contribution is believed to be an increase of student motivation, enhancement of student engagement and effectiveness of assessment process, so it is fast and fair.

Learning by game creation in introductory programming course: 5-Year-long study

The present study examines and discusses recent developments in teaching and learning programming, based on Game-based learning and Learning by game creation at Technical University of Košice. The innovations are related to learning algorithmic concepts using Karel the Robot game library as well as learning programming fundamentals by creating such library, progressively extended to the Sokoban game. Research activities are seen to satisfy the requirements for becoming familiar with programming basics, abilities to continue with studying modern programming technologies, and better application in practice. The paper closes with a look at the future for more innovations in the context of our game-based teaching methodology.

Agent-Based Model of the Spectrum Auctions with Sensing Imperfections in Dynamic Spectrum Access Networks

Cognitive radio (CR) is the underlying platform for the application of dynamic spectrum access (DSA) networks. Although the auction theory and spectrum trading mechanisms have been discussed in the CR related works, their joint techno-economic impact on the efficiency of distributed CR networks has not been researched yet. In this paper we assume heterogeneous primary channels with network availability statistics unknown to each secondary user (SU) terminal. In order to detect the idle primary user (PU) network channels, the SU terminals trigger regularly the spectrum sensing mechanism and make the cooperative decision regarding the channel status at the fusion center. The imperfections of the spectrum mechanism create the possibility of the channel collision, resulting in the existence of the risk (in terms of user collision) in the network. The spectrum trading within SU network is governed by the application of the sealed-bid first-price auction, which takes into account the channel valuation as well as the statistical probability of the risk existence. In order to maximize the long-term payoff, the SU terminals take an advantage of the reinforcement comparison strategy. The results demonstrate that in the investigated model, total revenue and total payoff of the SU operator (auctioneer) and SU terminals (bidders) are characterized by the existence of the global optimum, thus there exists the optimal sensing time guaranteeing the optimum economic factors for both SU operator and SU terminals.

Mobile support for learning of foreign languages

With population over 7.4 billion, communication barrier becomes a serious problem. To reduce such barriers, one of potential solutions can be lifelong learning of foreign languages. Authors of this study focus on process of learning foreign languages with an effective transformation to learning through smartphones. As a result, an e-learning Android application is presented, taking advantages of popular and successful “Callan” learning method.