@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}
}
@conference {LHF14,
	title = {The Connection of the Bug Density and Maintainability of Classes},
	booktitle = {8th International Workshop on Software Quality and Maintainability},
	series = {SQM},
	year = {2014},
	note = {Presentation only},
	month = {feb},
	address = {Antwerp, Belgium},
	abstract = {Measuring software product maintainability is a central issue in software engineering which led to a number of different practical quality models. Besides system level assessments it is also desirable that these models provide technical quality information at source code element level (e.g. classes, methods) to aid the improvement of the software. Although many existing models give an ordered list of source code elements that should be improved, it is unclear how these improvements affect other important quality indicators of the system, e.g. bug density. In this paper we empirically investigate the connection of bug numbers in the classes of different open-source systems and the class level maintainability measures of our ColumbusQM probabilistic quality model using open-access bug datasets. We show that classes with lower maintainability score contain significantly more bugs than more maintainable classes. Moreover, in terms of correctness and completeness, ColumbusQM competes with statistical and machine learning prediction models especially trained on the bug data using product metrics as predictors. This is a great achievement in the light of that our model needs no training and its purpose is different (e.g. to estimate testability, or development costs) than those of the bug prediction models. In summary, we show that improving the maintainability of a software according to the suggestions of our quality model will expectedly also reduce its bug density.},
	keywords = {Bug density, Bug prediction, Class level maintainability, ColumbusQM, ISO/IEC 25010, Software maintainability},
	author = {Lad{\'a}nyi, Gergely and P Heged{\H u}s and Rudolf Ferenc and Istv{\'a}n Siket and Tibor Gyim{\'o}thy}
}
