graph. In order to make a statement about this, we compared selected graph metrics of the simulated graph with the real graph. Compared metrics are, for example, the number of nodes, the average degree of the nodes, the density of the graph, or the diameter of the graph. For the comparison, we have designed two different scenarios.
First, the simulation model is instantiated with project specific parameters for each project to analyze and the simulation starts at the beginning of the project. Second, the simulation model is initialized with project specific parameters as well as the change coupling graph of a given year. Afterwards, the simulation starts at this point in time. Our main findings are that we can reproduce different growth types of the software with the project specific parameters and that metrics of the simulated graph fits the real metrics when the simulation is initialized with parameters starting approximately after one third of the project duration.
The third case study is about the mining and simulation of software refactorings [6].
With refactorings we can model the intention of developers and consider more as-pects concerning the quality of the evolving project. We want to show that we can retrieve parameters for a simulation model that uses graph transformation rules for the description of software refactorings [7]. Furthermore, we consider the impact of such an extended simulation model on the quality of the simulated change coupling graph. We figured out that the simulation of refactorings using graph transforma-tions works and that the growth trend of a project can be slightly improved when refactorings are simulated.
1.2. Thesis Impact
This work is part of the two SWZ projectsSimulation-Based Quality Assurance for Software Systems1 and Agent-based simulation models in support of monitoring the quality of software projects2.
During this work, the following papers have been published in peer reviewed confer-ence proceedings:
• Daniel Honsel, Niklas Fiekas, Verena Herbold, Marlon Welter, Tobias Ahlbrecht, Stephan Waack, J¨urgen Dix, Jens Grabowski, “Simulating Soft-ware Refactorings based on Graph Transformations“, in Post-Proceedings of the Clausthal-G¨ottingen International Workshop on Simulation Science 2017, Springer, 2018
1 https://www.simzentrum.de/en/education/softwarequalitaetssicherung-mit-hilfe-von-simulationsverfahren
2 https://www.simzentrum.de/en/research-projects/agent-based-simulation-models-in-support-of-monitoring-the-quality-of-software-projects
1. Introduction 4 Own contributions
I am the lead author of the paper. I contributed significantly to the design of the approach, the mining process and the evaluation of the approach. The used simulation framework is developed by N. Fiekas.
• Daniel Honsel, Verena Honsel, Marlon Welter, Jens Grabowski, Stephan Waack, “Monitoring Software Quality by Means of Simulation Methods“, in Proceedings of the 10th ACM/IEEE International Symposium on Empirical Software Engineering and Measurement (ESEM 2016), short paper, 2016
Own contributions
I am the lead author of the paper. I contributed significantly to the simulation model including different behavior strategies for the agents and its implemen-tation. Required simulation parameters are mined by V. Honsel. Furthermore, the conceptual work and the case study design was joined work with V. Honsel.
The automated assessment of software graphs was done by M. Welter.
Furthermore, some papers were published to which the author of this thesis con-tributed:
• Marlon Welter, Daniel Honsel, Verena Herbold, Andre Staedler, Jens Grabowski, Stephan Waack, “Assessing Simulated Software Graphs using Conditional Random Fields“, in Post-Proceedings of the Clausthal-G¨ottingen International Workshop on Simulation Science 2017, Springer, 2018
Own contributions
Own contributions for this paper include some conceptual work for the gener-ation of required software graphs. The CRF assessment tool is developed and evaluated by M. Welter.
• Tobias Ahlbrecht, J¨urgen Dix, Niklas Fiekas, Jens Grabowski, Verena Herbold, Daniel Honsel, Stephan Waack, Marlon Welter, “Agent-based simulation for software development processes“, on Proceedings of the 14th European Con-ference on Multi-Agent Systems (EUMAS 2016), Springer, 2016
Own contributions
Own contributions to this paper are the modeling and implementation of the non distributed version of the simulation model for software evolution. Fur-thermore, I was involved in the design of the proposed approach. The param-eter ming for the simulation model is done by V. Herbold. The distributed simulation framework is provided by T. Ahlbrecht and N. Fiekas.
• Verena Honsel, Daniel Honsel, Steffen Herbold, Jens Grabowski, Stephan Waack, “Mining Software Dependency Networks for Agent-Based Simulation of Software Evolution“, in Proceedings of the 30th IEEE/ACM International Conference on Automated Software Engineering Workshop (ASEW), The 4th International Workshop on Software Mining, 2015
5 1.2. Thesis Impact Own contributions
Own contributions to this paper include the design and the implementation of the required simulation model. Furthermore, I was involved in the design of the proposed approach concerning the determination of required simulation parameters. The mining process and the evaluation of the approach is provided by V. Honsel.
• Verena Honsel, Daniel Honsel, Jens Grabowski, Stephan Waack, “Developer Oriented and Quality Assurance Based Simulation of Software Processes“, in Proceedings of the Seminar Series on Advanced Techniques & Tools for Software Evolution (SATToSE 2015), 2015
Own contributions
This paper presents a summary of the papers [4], [8], and [9]. Thus, it is joined work of all involved authors. Own contributions include parts the conceptual work and parts of the summary of the considered papers.
• Verena Honsel, Daniel Honsel, Jens Grabowski, “Software Process Simulation based on Mining Software Repositories“, in Proceedings of the IEEE Inter-national Conference on Data Mining Workshop (ICDM 2014), short paper, 2014
Own contributions
The own contribution to this paper is the modeling and implementation of the agent-based simulation model. Furthermore, the evaluation of the simulated data was joined work with V.Honsel. The mining process and analysis of mined data is provided by V.Honsel.
In addition, the following book chapter has been published containing parts of the work developed in this thesis:
• Philip Makedonski, Verena Herbold, Steffen Herbold, Daniel Honsel, Jens Grabowski, Stephan Waack, “Mining Big Data for Analyzing and Simulating Collaboration Factors Influencing Software Development Decisions“, in Social Network Analysis: Interdisciplinary Approaches and Case Studies, CRC Press, 2016
Own contributions
The own contribution to this book chapter is the adaption of the agent-based simulation model developed by the author of this thesis. The model has been modified to support the collaborative networks analyzed in this chapter. The mining of software projects to build developer social networks as well as the analysis of these is provided by V. Herbold. This work establish an example application for the fine-grained developer behavior and collaboration model presented in this book chapter by Dr. P. Makedonski.
1. Introduction 6