@article{MTMT:34375495,
	title = {Concretization of Abstract Traffic Scene Specifications Using Metaheuristic Search},
	url = {https://m2.mtmt.hu/api/publication/34375495},
	author = {Babikian, Aren A. and Semeráth, Oszkár and Varró, Dániel},
	doi = {10.1109/TSE.2023.3331254},
	journal-iso = {IEEE T SOFTWARE ENG},
	journal = {IEEE TRANSACTIONS ON SOFTWARE ENGINEERING},
	volume = {50},
	unique-id = {34375495},
	issn = {0098-5589},
	abstract = {Existing safety assurance approaches for autonomous vehicles (AVs) perform system-level safety evaluation by placing the AV-under-test in challenging traffic scenarios captured by abstract scenario specifications and investigated in realistic traffic simulators. As a first step towards scenario-based testing of AVs, the initial scene of a traffic scenario must be concretized. In this context, the scene concretization challenge takes as input a high-level specification of abstract traffic scenes and aims to map them to concrete scenes where exact numeric initial values are defined for each attribute of a vehicle (e.g. position or velocity). In this paper, we propose a traffic scene concretization approach that places vehicles on realistic road maps such that they satisfy an extensible set of abstract constraints defined by an expressive scene specification language which also supports static detection of inconsistencies. Then, abstract constraints are mapped to corresponding numeric constraints, which are solved by metaheuristic search with customizable objective functions and constraint aggregation strategies. We conduct a series of experiments over three realistic road maps to compare eight configurations of our approach with three variations of the state-of-the-art Scenic tool, and to evaluate its scalability.},
	keywords = {Multiobjective optimization; evolutionary algorithm; Computer Science, Software Engineering; Scenario Description Language; Assurance for autonomous vehicles; traffic scene concretization},
	year = {2024},
	eissn = {1939-3520},
	pages = {48-68},
	orcid-numbers = {Varró, Dániel/0000-0002-8790-252X}
}

@inproceedings{MTMT:33648748,
	title = {Consistent Scene Graph Generation by Constraint Optimization},
	url = {https://m2.mtmt.hu/api/publication/33648748},
	author = {Chen, Boqi and Marussy, Kristóf and Pilarski, Sebastian and Semeráth, Oszkár and Varró, Dániel},
	booktitle = {ASE '22: Proceedings of the 37th IEEE/ACM International Conference on Automated Software Engineering},
	doi = {10.1145/3551349.3560433},
	unique-id = {33648748},
	year = {2022},
	pages = {1-13},
	orcid-numbers = {Marussy, Kristóf/0000-0002-9135-8256; Varró, Dániel/0000-0002-8790-252X}
}

@inproceedings{MTMT:33283704,
	title = {An Initial Performance Analysis of Graph Predicate Evaluation over Partial Models},
	url = {https://m2.mtmt.hu/api/publication/33283704},
	author = {Ficsor, Attila and Semeráth, Oszkár},
	booktitle = {Proceedings of the 29th Minisymposium of the Department of Measurement and Information Systems Budapest University of Technology and Economics},
	doi = {10.3311/MINISY2022-001},
	unique-id = {33283704},
	year = {2022},
	pages = {1-4},
	orcid-numbers = {Ficsor, Attila/0000-0002-0541-4590}
}

@article{MTMT:32394785,
	title = {Automated generation of consistent models using qualitative abstractions and exploration strategies},
	url = {https://m2.mtmt.hu/api/publication/32394785},
	author = {Babikian, Aren A. and Semeráth, Oszkár and Li, Anqi and Marussy, Kristóf and Varró, Dániel},
	doi = {10.1007/s10270-021-00918-6},
	journal-iso = {SOFTW SYST MODEL},
	journal = {SOFTWARE AND SYSTEMS MODELING},
	volume = {21},
	unique-id = {32394785},
	issn = {1619-1366},
	abstract = {Automatically synthesizing consistent models is a key prerequisite for many testing scenarios in autonomous driving to ensure a designated coverage of critical corner cases. An inconsistent model is irrelevant as a test case (e.g., false positive); thus, each synthetic model needs to simultaneously satisfy various structural and attribute constraints, which includes complex geometric constraints for traffic scenarios. While different logic solvers or dedicated graph solvers have recently been developed, they fail to handle either structural or attribute constraints in a scalable way. In the current paper, we combine a structural graph solver that uses partial models with an SMT-solver and a quadratic solver to automatically derive models which simultaneously fulfill structural and numeric constraints, while key theoretical properties of model generation like completeness or diversity are still ensured. This necessitates a sophisticated bidirectional interaction between different solvers which carry out consistency checks, decision, unit propagation, concretization steps. Additionally, we introduce custom exploration strategies to speed up model generation. We evaluate the scalability and diversity of our approach, as well as the influence of customizations, in the context of four complex case studies.},
	keywords = {Model generation; Exploration strategy; Partial model; Graph solver; SMT-solver; Numeric solver; Test scenario synthesis},
	year = {2022},
	eissn = {1619-1374},
	pages = {1763-1787},
	orcid-numbers = {Marussy, Kristóf/0000-0002-9135-8256; Varró, Dániel/0000-0002-8790-252X}
}

@article{MTMT:31360895,
	title = {Automated Generation of Consistent Graph Models with Multiplicity Reasoning},
	url = {https://m2.mtmt.hu/api/publication/31360895},
	author = {Marussy, Kristóf and Semeráth, Oszkár and Varró, Dániel},
	doi = {10.1109/TSE.2020.3025732},
	journal-iso = {IEEE T SOFTWARE ENG},
	journal = {IEEE TRANSACTIONS ON SOFTWARE ENGINEERING},
	volume = {48},
	unique-id = {31360895},
	issn = {0098-5589},
	abstract = {Advanced tools used in model-based systems engineering (MBSE) frequently represent their models as graphs. In order to test those tools, the automated generation of well-formed (or intentionally malformed) graph models is necessitated which is often carried out by solver-based model generation techniques. In many model generation scenarios, one needs more refined control over the generated unit tests to focus on the more relevant models. Type scopes allow to precisely define the required number of newly generated elements, thus one can avoid the generation of unrealistic and highly symmetric models having only a single type of elements. In this paper, we propose a 3-valued scoped partial modeling formalism, which innovatively extends partial graph models with predicate abstraction and counter abstraction. As a result, well-formedness constraints and multiplicity requirements can be evaluated in an approximated way on incomplete (unfinished) models by using advanced graph query engines with numerical solvers (e.g., IP or LP solvers). Based on the refinement of 3-valued scoped partial models, we propose an efficient model generation algorithm that generates models that are both well-formed and satisfy the scope requirements. We show that the proposed approach scales significantly better than existing SAT-solver techniques or the original graph solver without multiplicity reasoning. We illustrate our approach in a complex design-space exploration case study of collaborating satellites introduced by researchers at NASA JPL.},
	year = {2022},
	eissn = {1939-3520},
	pages = {1610-1629},
	orcid-numbers = {Marussy, Kristóf/0000-0002-9135-8256; Varró, Dániel/0000-0002-8790-252X}
}

@inproceedings{MTMT:32605462,
	title = {Towards the Formal Semantics of Scenario Tests for Autonomous Vehicles},
	url = {https://m2.mtmt.hu/api/publication/32605462},
	author = {Kovacs, Laszlo and Semeráth, Oszkár},
	booktitle = {2021 10th Latin-American Symposium on Dependable Computing (LADC)},
	doi = {10.1109/LADC53747.2021.9672554},
	unique-id = {32605462},
	year = {2021},
	pages = {01-04}
}

@article{MTMT:32028274,
	title = {Automated Generation of Consistent, Diverse and Structurally Realistic Graph Models},
	url = {https://m2.mtmt.hu/api/publication/32028274},
	author = {Semeráth, Oszkár and Aren, A. Babikian and Boqi, Chen and Chuning, Li and Marussy, Kristóf and Szárnyas, Gábor and Varró, Dániel},
	doi = {10.1007/s10270-021-00884-z},
	journal-iso = {SOFTW SYST MODEL},
	journal = {SOFTWARE AND SYSTEMS MODELING},
	volume = {20},
	unique-id = {32028274},
	issn = {1619-1366},
	abstract = {In this paper, we present a novel technique to automatically synthesize consistent, diverse and structurally realistic domain-specific graph models. A graph model is (1) consistent if it is metamodel-compliant and it satisfies the well-formedness constraints of the domain; (2) it is diverse if local neighborhoods of nodes are highly different; and (1) it is structurally realistic if a synthetic graph is at a close distance to a representative real model according to various graph metrics used in network science, databases or software engineering. Our approach grows models by model extension operators using a hill-climbing strategy in a way that (A) ensures that there are no constraint violation in the models (for consistency reasons), while (B) more realistic candidates are selected to minimize a target metric value (wrt. the representative real model). We evaluate the effectiveness of the approach for generating realistic models using multiple metrics for guidance heuristics and compared to other model generators in the context of three case studies with a large set of real human models. We also highlight that our technique is able to generate a diverse set of models, which is a requirement in many testing scenarios.},
	year = {2021},
	eissn = {1619-1374},
	pages = {1713-1734},
	orcid-numbers = {Marussy, Kristóf/0000-0002-9135-8256; Varró, Dániel/0000-0002-8790-252X}
}

@inproceedings{MTMT:31872205,
	title = {Automated generation of consistent models with structural and attribute constraints},
	url = {https://m2.mtmt.hu/api/publication/31872205},
	author = {Semeráth, Oszkár and Babikian, Aren A. and Li, Anqi and Marussy, Kristóf and Varró, Dániel},
	booktitle = {Proceedings of the 23rd ACM/IEEE International Conference on Model Driven Engineering Languages and Systems},
	doi = {10.1145/3365438.3410962},
	unique-id = {31872205},
	year = {2020},
	pages = {187-199},
	orcid-numbers = {Marussy, Kristóf/0000-0002-9135-8256; Varró, Dániel/0000-0002-8790-252X}
}

@inproceedings{MTMT:31872191,
	title = {Automated video game world map synthesis by model-based techniques},
	url = {https://m2.mtmt.hu/api/publication/31872191},
	author = {Chen, Boqi and Havelock, Dylan and Plante, Connor and Sukkarieh, Michael and Semeráth, Oszkár and Varró, Dániel},
	booktitle = {Proceedings of the 23rd ACM/IEEE International Conference on Model Driven Engineering Languages and Systems: Companion Proceedings},
	doi = {10.1145/3417990.3422001},
	unique-id = {31872191},
	year = {2020},
	pages = {1-5},
	orcid-numbers = {Varró, Dániel/0000-0002-8790-252X}
}

@article{MTMT:31361799,
	title = {A specification language for consistent model generation based on partial models},
	url = {https://m2.mtmt.hu/api/publication/31361799},
	author = {Marussy, Kristóf and Semeráth, Oszkár and Aren, A. Babikian and Varró, Dániel},
	doi = {10.5381/jot.2020.19.3.a12},
	journal-iso = {J OBJECT TECHNOL},
	journal = {JOURNAL OF OBJECT TECHNOLOGY},
	volume = {19},
	unique-id = {31361799},
	issn = {1660-1769},
	year = {2020},
	pages = {1-22},
	orcid-numbers = {Marussy, Kristóf/0000-0002-9135-8256; Varró, Dániel/0000-0002-8790-252X}
}