@conference {LTF15,
	title = {A Software Quality Model for {RPG}},
	booktitle = {Proceedings of the 22nd IEEE International Conference on Software Analysis, Evolution, and Reengineering (SANER 2015)},
	year = {2015},
	month = {mar},
	pages = {91{\textendash}100},
	publisher = {IEEE Computer Society},
	organization = {IEEE Computer Society},
	address = {Montr{\'e}al, Canada},
	abstract = {The IBM i mainframe was designed to manage business applications for which the reliability and quality is a matter of national security. The RPG programming language is the most frequently used one on this platform. The maintainability of the source code has big influence on the development costs, probably this is the reason why it is one of the most attractive, observed and evaluated quality characteristic of all. For improving or at least preserving the maintainability level of software it is necessary to evaluate it regularly. In this study we present a quality model based on the ISO/IEC 25010 international standard for evaluating the maintainability of software systems written in RPG. As an evaluation step of the quality model we show a case study in which we explain how we integrated the quality model as a continuous quality monitoring tool into the business processes of a mid-size software company which has more than twenty years of experience in developing RPG applications.},
	keywords = {Case Study, IBM i mainframe, ISO/IEC 25010, RPG quality model, Software maintainability},
	doi = {10.1109/SANER.2015.7081819},
	url = {http://ieeexplore.ieee.org/document/7081819/},
	author = {Lad{\'a}nyi, Gergely and T{\'o}th, Zolt{\'a}n and Rudolf Ferenc and Keresztesi, Tibor}
}
@article {FHV14,
	title = {Connection Between Version Control Operations and Quality Change of the Source Code},
	journal = {Acta Cybernetica},
	volume = {21},
	number = {4},
	year = {2014},
	pages = {585{\textendash}607},
	abstract = {Software erosion is a well-known phenomena, meaning that software quality is continuously decreasing due to the ever-ongoing modifications in the source code. In this research work we investigated this phenomena by studying the impact of version control commit operations (add, update, delete) on the quality of the code. We calculated the ISO/IEC 9126 quality attributes for thousands of revisions of an industrial and three open-source software systems with the help of the Columbus Quality Model. We also collected the cardinality of each version control operation type for every investigated revision. We performed Chisquared tests on contingency tables with rows of quality change and columns of version control operation commit types. We compared the results with random data as well. We identified that the relationship between the version control operations and quality change is quite strong. Great maintainability improvements are mostly caused by commits containing Add operation. Commits containing file updates only tend to have a negative impact on the quality. Deletions have a weak connection with quality, and we could not formulate a general statement.},
	keywords = {Case Study, ISO/IEC 9126, Software Erosion, Software maintainability, Source Code Version Control},
	issn = {0324-721X},
	url = {http://publicatio.bibl.u-szeged.hu/8394/},
	author = {Farag{\'o}, Csaba and P Heged{\H u}s and V{\'e}gh, {\'A}d{\'a}m Zolt{\'a}n and Rudolf Ferenc}
}
@conference {FHF14,
	title = {The Impact of Version Control Operations on the Quality Change of the Source Code},
	booktitle = {Proceedings of the 14th International Conference on Computational Science and Its Applications (ICCSA 2014)},
	series = {Lecture Notes in Computer Science (LNCS)},
	volume = {8583},
	year = {2014},
	month = {jun},
	pages = {353{\textendash}369},
	publisher = {Springer-Verlag},
	organization = {Springer-Verlag},
	address = {Guimar{\~a}es, Portugal},
	abstract = {The number of software systems under development and maintenance is rapidly increasing. The quality of a system{\textquoteright}s source code tends to decrease during its lifetime which is a problem because maintaining low quality code consumes a big portion of the available efforts. In this research we investigated one aspect of code change, the version control commit operations (add, update, delete). We studied the impact of these operations on the maintainability of the code. We calculated the ISO/IEC 9126 quality attributes for thousands of revisions of an industrial and three open-source software systems. We also collected the cardinality of each version control operation type for every investigated revision. Based on these data, we identified that operation Add has a rather positive, while operation Update has a rather negative effect on the quality. On the other hand, for operation Delete we could not find a clear connection to quality change.},
	keywords = {Case Study, ISO/IEC 9126, Software Erosion, Software maintainability, Source Code Version Control},
	doi = {10.1007/978-3-319-09156-3_26},
	url = {https://link.springer.com/chapter/10.1007\%2F978-3-319-09156-3_26},
	author = {Farag{\'o}, Csaba and P Heged{\H u}s and Rudolf Ferenc}
}
