@conference {440,
	title = {GVGExp: Communication-Constrained Multi-Robot Exploration System based on Generalized Voronoi Graphs},
	booktitle = {International Symposium on Multi-Robot and Multi-Agent Systems (MRS)},
	year = {2021},
	publisher = {IEEE},
	organization = {IEEE},
	address = {Cambridge, United Kingdom},
	abstract = {This paper presents GVGExp, a recurrent-connectivity exploration strategy for multi-robot systems to discover unknown environments under communication-constrained conditions. A robust multi-robot exploration strategy with communication constraints is important to accomplish several applications, e.g., underwater or planetary exploration. Mainstream multi-robot exploration strategies have considered unlimited communication. In addition, these strategies delegate the resolution of potential path collisions to local planners. In this paper, we explicitly focus on minimizing the number of communication events between robots given the limited bandwidth that can be available in real missions, as well as explicitly minimizing potential path interference between robots. GVGExp incrementally builds a Generalized Voronoi Graph (GVG), which is used by the robots to determine the topology of the environment. We introduce a novel property of the GVG called gate to identify a region (subtree) that is uniquely assigned to each robot, with no overlap, thus minimizing potential path interference. Whenever a robot finishes exploring a region, in a depth-first search fashion, or finds a loop connecting to other parts of the environment, the robot shares information with other robots that are in range to enable coordination. We performed numerous simulations to evaluate our proposed strategy and compared it with other state-of-the-art methods. Experimental results show that GVGExp is able to explore the environments in a relatively short amount of time, significantly reducing communication events and path interference.},
	doi = {10.1109/MRS50823.2021.9620554},
	url = {https://ieeexplore.ieee.org/document/9620554/},
	author = {Masaba, Kizito and Quattrini~Li, Alberto}
}
@conference {413,
	title = {AmphiLight: Direct Air-Water Communication with Laser Light},
	booktitle = {17th USENIX Symposium on Networked Systems Design and Implementation (NSDI 20)},
	year = {2020},
	publisher = {USENIX Association},
	organization = {USENIX Association},
	address = {Santa Clara, CA},
	isbn = {978-1-939133-13-7},
	url = {https://www.usenix.org/conference/nsdi20/presentation/carver},
	author = {Charles J. Carver and Zhao Tian and Hongyong Zhang and Kofi M. Odame and Quattrini~Li, Alberto and Xia Zhou}
}
@conference {441,
	title = {DeepURL: Deep Pose Estimation Framework for Underwater Relative Localization},
	booktitle = {IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)},
	year = {2020},
	publisher = {IEEE},
	organization = {IEEE},
	address = {Las Vegas, NV, USA},
	doi = {10.1109/IROS45743.202010.1109/IROS45743.2020.9341201},
	url = {https://ieeexplore.ieee.org/document/9341201/},
	author = {Joshi, Bharat and Modasshir, Md and Manderson, Travis and Damron, Hunter and Xanthidis, Marios and Quattrini~Li, Alberto and Rekleitis, Ioannis and Dudek, Gregory}
}
@article {412,
	title = {Exploration and Mapping with Groups of Robots: Recent Trends},
	journal = {Current Robotics Reports},
	year = {2020},
	month = {Sep-09-2020},
	abstract = {Purpose of Review
Multi-robot exploration{\textemdash}i.e., the problem of mapping unknown features of an environment{\textemdash}is fundamental in many tasks, including search and rescue, planetary exploration, and environmental monitoring. This article surveys recent literature with the aim at identifying current research trends, open challenges, and future directions.

Recent Findings
Since the first formalization of the exploration problem, current research has extended systems and algorithms to map 3D environments and more complex phenomena and considered real-world constraints. Deep learning-based approaches have seen some preliminary applications in decision-making.

Summary
While current research has been progressing towards systems that can work in the real world, long-term exploration in large unstructured environments with complex phenomena to map is still an open problem. This introduces opportunities for exciting research, including but not limited to generalized frameworks that bridge the gap between theory and practice, learning-based approaches, and robustness to failure and attacks, so that robots can be deployed safely in real-world environments.},
	keywords = {Exploration, Mapping, Multi-robot systems},
	doi = {10.1007/s43154-020-00030-5},
	url = {http://link.springer.com/10.1007/s43154-020-00030-5},
	author = {Quattrini~Li, Alberto}
}
@conference {Liang2020,
	title = {FreeBOT: A Freeform Modular Self-reconfigurable Robot with Arbitrary Connection Point - Design and Implementation},
	booktitle = {2020 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)},
	year = {2020},
	pages = {6506{\textendash}6513},
	publisher = {IEEE},
	organization = {IEEE},
	address = {Las Vegas, NV, USA},
	abstract = {This paper proposes a novel modular selfreconfigurable robot (MSRR) "FreeBOT", which can be connected freely at any point on other robots. FreeBOT is mainly composed of two parts: a spherical ferromagnetic shell and an internal magnet. The connection between the modules is genderless and instant, since the internal magnet can freely attract other FreeBOT spherical ferromagnetic shells, and not need to be precisely aligned with the specified connector. This connection method has fewer physical constraints, so the FreeBOT system can be extended to more configurations to meet more functional requirements. FreeBOT can accomplish multiple tasks although it only has two motors: module independent movement, connector management and system reconfiguration. FreeBOT can move independently on the plane, and even climb on ferromagnetic walls; a group of FreeBOTs can traverse complex terrain. Numerous experiments have been conducted to test its function, which shows that the FreeBOT system has great potential to realize a freeform robotic system.},
	keywords = {Connectors, Intelligent robots, Task analysis},
	isbn = {978-1-7281-6213-3},
	issn = {2153-0858},
	doi = {10.1109/IROS45743.2020.9341129},
	author = {Guanqi Liang and Haobo Luo and Ming Li and Huihuan Qian and Tin Lun Lam}
}
@article {411,
	title = {Multi-robot online sensing strategies for the construction of communication maps},
	journal = {Autonomous Robots},
	volume = {44},
	year = {2020},
	month = {Jan-03-2020},
	pages = {299 - 319},
	abstract = {This paper tackles the problem of constructing a communication map of a known environment using multiple robots. A communication map encodes information on whether two robots can communicate when they are at two arbitrary locations and plays a fundamental role for a multi-robot system deployment to reliably and effectively achieve a variety of tasks, such as environmental monitoring and exploration. Previous work on communication map building typically considered only scenarios with a fixed base station and designed offline methods, which did not exploit data collected online by the robots. This paper proposes Gaussian Process-based online methods to efficiently build a communication map with multiple robots. Such robots form a mesh network, where there is no fixed base station. Specifically, we provide two leader-follower online sensing strategies to coordinate and guide the robots while collecting data. Furthermore, we improve the performance and computational efficiency by exploiting prior communication models that can be built from the physical map of the environment. Extensive experimental results in simulation and with a team of TurtleBot 2 platforms validate the approach.},
	keywords = {Communication maps, Multi-robot systems, Sensing strategies},
	issn = {0929-5593},
	doi = {10.1007/s10514-019-09862-3},
	url = {http://link.springer.com/10.1007/s10514-019-09862-3},
	author = {Quattrini~Li, Alberto and Penumarthi, Phani Krishna and Banfi, Jacopo and Basilico, Nicola and O{\textquoteright}Kane, Jason M. and Rekleitis, Ioannis and Nelakuditi, Srihari and Amigoni, Francesco}
}
@conference {Luo2020,
	title = {An Obstacle-crossing Strategy Based on the Fast Self-reconfiguration for Modular Sphere Robots},
	booktitle = {2020 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)},
	year = {2020},
	pages = {3296{\textendash}3303},
	publisher = {IEEE},
	organization = {IEEE},
	address = {Las Vegas, NV, USA},
	abstract = {This paper introduces an obstacle-crossing strategy, and the self-reconfiguration algorithm for a new class of modular robots called the rolling sphere, which can fit obstacles represented by cubes of different sizes due to the chain connection of multiple spheres. For the self-reconfiguration of the rolling spheres, a large gradient is obtained by classifying its action types and hierarchically minimizing the distance between the initial configuration and the final configuration. The most direct use of this large gradient is the fast crossing of various obstacles, by jointing multiple self-reconfigurations according to the OctoMap of the obstacles. It is verified in simulation that the self-reconfiguration takes full advantage of the parallel movement of multiple modules to reduce the total time steps, and the obstacle-crossing strategy can adapt to a variety of obstacles.},
	keywords = {Adaptation models, Classification algorithms, Intelligent robots},
	isbn = {978-1-7281-6213-3},
	issn = {2153-0858},
	doi = {10.1109/IROS45743.2020.9341162},
	author = {Haobo Luo and Ming Li and Guangqi Liang and Huihuan Qian and Tin Lun Lam}
}
@conference {Li2020,
	title = {Robot-to-Robot Relative Pose Estimation based on Semidefinite Relaxation Optimization},
	booktitle = {2020 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)},
	year = {2020},
	pages = {4491{\textendash}4498},
	publisher = {IEEE},
	organization = {IEEE},
	address = {Las Vegas, NV, USA},
	abstract = {In this paper, the 2D robot-to-robot relative pose (position and orientation) estimation problem based on ego-motion and noisy distance measurements is considered. We address this problem using an optimization-based method, which does not require complicated numerical analysis while yields no inferior relative localization (RL) results compared to existing approaches. In particular, we start from a state-of-the-art method named square distances weighted least square (SD-WLS), and reformulate it as a non-convex quadratically constrained quadratic programming (QCQP) problem. To handle its non-convex nature, a semidefinite programming (SDP) relaxation optimization-based method is proposed, and we prove that the relaxation is tight when measurements are free from noise or just corrupted by small noise. Further, to obtain the optimal solution of the relative pose estimation problem in the sense of maximum likelihood estimation (MLE), a theoretically optimal WLS method is developed to refine the estimate from the SDP optimization. Comprehensive simulations and well-designed experiments are presented for validating the tightness of the SDP relaxation, and the effectiveness of the proposed algorithm is highlighted by comparing it to the existing approaches.},
	keywords = {Maximum likelihood estimation, Noise measurement, Optimization, Particle measurements, Pose estimation, Quadratic programming, Two dimensional displays},
	isbn = {978-1-7281-6213-3},
	issn = {2153-0858},
	doi = {10.1109/IROS45743.2020.9341568},
	author = {Ming Li and Guanqi Liang and Haobo Luo and Huihuan Qian and Tin Lun Lam}
}
@book {414,
	title = {Online Update of Communication Maps for Exploring Multirobot Systems Under Connectivity Constraints},
	series = {Springer Proceedings in Advanced Robotics - Distributed Autonomous Robotic Systems},
	volume = {9},
	year = {2019},
	pages = {513 - 526},
	publisher = {Springer International Publishing},
	organization = {Springer International Publishing},
	address = {Cham},
	keywords = {Communication, Exploration, Multirobot systems},
	isbn = {978-3-030-05815-9},
	issn = {2511-1256},
	doi = {10.1007/978-3-030-05816-610.1007/978-3-030-05816-6_36},
	url = {http://link.springer.com/10.1007/978-3-030-05816-6},
	author = {Amigoni, Francesco and Banfi, Jacopo and Basilico, Nicola and Rekleitis, Ioannis and Quattrini~Li, Alberto},
	editor = {Correll, Nikolaus and Schwager, Mac and Otte, Michael}
}
@conference {410,
	title = {ROS-CBT: Communication Benchmarking Tool for the Robot Operating System: Extended Abstract},
	booktitle = {International Symposium on Multi-Robot and Multi-Agent Systems (MRS)},
	year = {2019},
	publisher = {IEEE},
	organization = {IEEE},
	address = {New Brunswick, NJ, USA},
	abstract = {Simulation plays a critical role in robotics as it allows verification and it provides evaluations of robot software before real world deployment. One prevalent limitation of robotic simulators that support the Robot Operating System, ROS - a de facto standard for developing robotic software - is the absence of communication simulators. This poses a serious challenge in testing software for multi-robot systems (MRS) that use explicit communication, hence limiting the development of this technology. Figure 1 illustrates the problem tackled in this paper.},
	doi = {10.1109/MRS47350.201910.1109/MRS.2019.8901094},
	url = {https://ieeexplore.ieee.org/document/8901094/},
	author = {Masaba, Kizito and Quattrini~Li, Alberto}
}
@conference {419,
	title = {Autonomous Marine Sampling Enhanced by Strategically Deployed Drifters in Marine Flow Fields},
	booktitle = {OCEANS 2018 MTS/IEEE Charleston},
	year = {2018},
	publisher = {IEEE},
	organization = {IEEE},
	address = {Charleston, SC},
	doi = {10.1109/OCEANS.2018.8604873},
	url = {https://ieeexplore.ieee.org/document/8604873/},
	author = {Hansen, Johanna and Manjanna, Sandeep and Quattrini~Li, Alberto and Rekleitis, Ioannis and Dudek, Gregory}
}
@conference {420,
	title = {Experimental Analysis of Radio Communication Capabilities of Multiple Autonomous Surface Vehicles},
	booktitle = {OCEANS 2018 MTS/IEEE Charleston},
	year = {2018},
	publisher = {IEEE},
	organization = {IEEE},
	address = {Charleston, SC},
	doi = {10.1109/OCEANS.2018.8604713},
	url = {https://ieeexplore.ieee.org/document/8604713},
	author = {Malebary, Sharaf and Moulton, Jason and Quattrini~Li, Alberto and Rekleitis, Ioannis}
}
@conference {416,
	title = {Heterogeneous Multirobot System for Exploration and Strategic Water Sampling},
	booktitle = {IEEE International Conference on Robotics and Automation (ICRA)},
	year = {2018},
	url = {https://doi.org/10.1109/ICRA.2018.8460759},
	author = {Sandeep Manjanna and Quattrini~Li, Alberto and Ryan N. Smith and Ioannis Rekleitis and Gregory Dudek}
}
@conference {417,
	title = {Multi-robot Dubins Coverage with Autonomous Surface Vehicles},
	booktitle = {IEEE International Conference on Robotics and Automation (ICRA)},
	year = {2018},
	url = {https://doi.org/10.1109/ICRA.2018.8460661},
	author = {Nare Karapetyan and Jason Moulton and Jeremy S. Lewis and Quattrini~Li, Alberto and Jason M. O{\textquoteright}Kane and Ioannis Rekleitis}
}
@article {331,
	title = {Strategies for coordinated multirobot exploration with recurrent connectivity constraints},
	journal = {Autonomous Robots},
	volume = {42},
	year = {2018},
	pages = {875{\textendash}894},
	abstract = {During several applications, such as search and rescue, robots must discover new information about the environment and, at the same time, share operational knowledge with a base station through an ad hoc network. In this paper, we design exploration strategies that allow robots to coordinate with teammates to form such a network in order to satisfy recurrent connectivity constraints{\textendash}-that is, data must be shared with the base station when making new observations at the assigned locations. Current approaches lack in flexibility due to the assumptions made about the communication model. Furthermore, they are sometimes inefficient because of the synchronous way they work: new plans are issued only once all robots have reached their goals. This paper introduces two novel asynchronous strategies that work with arbitrary communication models. In this paper, {\textquoteleft}asynchronous{\textquoteright} means that it is possible to issue new plans to subgroups of robots, when they are ready to receive them. First, we propose a single-stage strategy based on Integer Linear Programming for selecting and assigning robots to locations. Second, we design a two-stage strategy to improve computational efficiency, by separating the problem of locations{\textquoteright} selection from that of robot-location assignments. Extensive testing both in simulation and with real robots show that the proposed strategies provide good situation awareness at the base station while efficiently exploring the environment.},
	keywords = {Communication constraints, Exploration, Multirobot systems, Recurrent connectivity},
	doi = {10.1007/s10514-017-9652-y},
	author = {Jacopo Banfi and Quattrini~Li, Alberto and Ioannis Rekleitis and Francesco Amigoni and Nicola Basilico}
}
@conference {415,
	title = {Underwater Surveying via Bearing Only Cooperative Localization},
	booktitle = {IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)},
	year = {2018},
	publisher = {IEEE},
	organization = {IEEE},
	address = {Madrid},
	doi = {10.1109/IROS.2018.8593431},
	url = {https://ieeexplore.ieee.org/document/8593431},
	author = {Damron, Hunter and Quattrini~Li, Alberto and Rekleitis, Ioannis}
}
@conference {334,
	title = {Collaborative Sampling Using Heterogeneous Marine Robots Driven by Visual Cues},
	booktitle = {Proceedings of the Conference on Computer and Robot Vision (CRV)},
	year = {2017},
	abstract = {This paper addresses distributed data sampling in marine environments using robotic devices. We present a method to strategically sample locally observable features using two classes of sensor platforms. Our system consists of a sophisticated autonomous surface vehicle (ASV) which strategically samples based on information provided by a team of inexpensive sensor nodes. The sensor nodes effectively extend the observational capabilities of the vehicle by capturing georeferenced samples from disparate and moving points across the region. The ASV uses this information, along with its own observations, to plan a path so as to sample points which it expects to be particularly informative. We compare our approach to a traditional exhaustive survey approach and show that we are able to effectively represent a region with less energy expenditure. We validate our approach through simulations and test the system on real robots in field.},
	doi = {10.1109/CRV.2017.49},
	author = {Sandeep Manjanna and Johanna Hansen and Quattrini~Li, Alberto and Ioannis Rekleitis and Gregory Dudek}
}
@conference {332,
	title = {Multirobot Exploration for Building Communication Maps with Prior from Communication Models},
	booktitle = {Proceedings of the International Symposium on Multi-Robot and Multi-Agent Systems (MRS)},
	year = {2017},
	author = {Phani Krishna Penumarthi and Quattrini~Li, Alberto and Jacopo Banfi and Nicola Basilico and Francesco Amigoni and Jason O{\textquoteright}Kane and Ioannis Rekleitis and Srihari Nelakuditi}
}
@conference {333,
	title = {Multirobot Online Construction of Communication Maps},
	booktitle = {Proceedings of the IEEE International Conference on Robotics and Automation (ICRA)},
	year = {2017},
	abstract = {The importance of communication in many multirobot information-gathering tasks requires the availability of reliable communication maps. These provide estimates of the radio signal strength and can be used to predict the presence of communication links between different locations of the environment. In the problem we consider, a team of mobile robots has to build such maps autonomously in a robot-to-robot communication setting. The solution we propose models the signal{\textquoteright}s distribution with a Gaussian Process and exploits different online sensing strategies to coordinate and guide the robots during their data acquisition. Our methods show interesting operative insights both in simulations and on real TurtleBot 2 platforms.},
	doi = {10.1109/ICRA.2017.7989300},
	author = {Jacopo Banfi and Quattrini~Li, Alberto and Nicola Basilico and Ioannis Rekleitis and Francesco Amigoni}
}
@conference {171,
	title = {Asynchronous Multirobot Exploration under Recurrent Connectivity Constraints},
	booktitle = {Proceedings of the IEEE International Conference on Robotics and Automation (ICRA)},
	year = {2016},
	address = {Stockholm, Sweden},
	abstract = {In multirobot exploration under centralized control, communication plays an important role in constraining the team exploration strategy. Recurrent connectivity is a way to define communication constraints for which robots must
connect to a base station only when making new observations.
This paper studies effective multirobot exploration strategies under recurrent connectivity by considering a centralized and
asynchronous planning framework. We formalize the problem of selecting the optimal set of locations robots should reach, provide an exact formulation to solve it, and devise an approximation algorithm to obtain efficient solutions with a bounded loss of optimality. Experiments in simulation and on real robots
evaluate our approach in a number of settings.},
	author = {Jacopo Banfi and Alberto Quattrini~Li and Nicola Basilico and Ioannis Rekleitis and Francesco Amigoni}
}
@conference {335,
	title = {Data Correlation and Comparison from Multiple Sensors over a Coral Reef with a Team of Heterogeneous Aquatic Robots},
	booktitle = {International Symposium on Experimental Robotics (ISER)},
	year = {2016},
	abstract = {This paper presents experimental insights from the deployment of an ensemble of heterogeneous autonomous sensor systems over a shallow coral reef. Visual, inertial, GPS, and ultrasonic data collected are compared and correlated to produce a comprehensive view of the health of the coral reef. Coverage strategies are discussed with a focus on the use of informed decisions to maximize the information collected during a fixed period of time.},
	doi = {10.1007/978-3-319-50115-4_62},
	author = {Quattrini~Li, Alberto and Ioannis Rekleitis and Sandeep Manjanna and Nikhil Kakodkar and Johanna Hansen and Gregory Dudek and Leonardo Bobadilla and Jacob Anderson and Ryan N. Smith}
}
@article {167,
	title = {A semantically-informed multirobot system for exploration of relevant areas in search and rescue settings},
	journal = {Autonomous Robots},
	year = {2015},
	pages = {1{\textendash}17},
	abstract = {Coordinated multirobot exploration involves autonomous discovering and mapping of the features of initially unknown environments by using multiple robots. Autonomously exploring mobile robots are usually driven, both in selecting locations to visit and in assigning them to robots, by knowledge of the already explored portions of the environment, often represented in a metric map. In the literature, some works addressed the use of semantic knowledge in exploration, which, embedded in a semantic map, associates spatial concepts (like {\textquoteleft}rooms{\textquoteright} and {\textquoteleft}corridors{\textquoteright}) with metric entities, showing its effectiveness in improving the total area explored by robots. In this paper, we build on these results and propose a system that exploits semantic information to push robots to explore relevant areas of initially unknown environments, according to a priori information provided by human users. Discovery of relevant areas is significant in some search and rescue settings, in which human rescuers can instruct robots to search for victims in specific areas, for example in cubicles if a disaster happened in an office building during working hours. We propose to speed up the exploration of specific areas by using semantic information both to select locations to visit and to determine the number of robots to allocate to those locations. In this way, for example, more robots could be assigned to a candidate location in a corridor, so the attached rooms can be explored faster. We tested our semantic-based multirobot exploration system within a reliable robot simulator and we evaluated its performance in realistic search and rescue indoor settings with respect to state-of-the-art approaches.},
	keywords = {Coordinated multirobot exploration, Search and Rescue, Semantic map},
	issn = {1573-7527},
	doi = {10.1007/s10514-015-9480-x},
	url = {http://dx.doi.org/10.1007/s10514-015-9480-x},
	author = {Quattrini~Li, Alberto and Cipolleschi, Riccardo and Giusto, Michele and Amigoni, Francesco}
}
@inbook {170,
	title = {How Much Worth Is Coordination of Mobile Robots for Exploration in Search and Rescue?},
	booktitle = {RoboCup 2012: Robot Soccer World Cup XVI},
	series = {Lecture Notes in Computer Science},
	number = {7500},
	year = {2013},
	pages = {106{\textendash}117},
	publisher = {Springer},
	organization = {Springer},
	chapter = {How Much Worth Is Coordination of Mobile Robots for Exploration in Search and Rescue?},
	address = {Berlin, Heidelberg},
	abstract = {Exploration of unknown environments is an enabling task for several applications, including map building and search and rescue. It is widely recognized that several benefits can be derived from deploying multiple mobile robots in exploration, including increased robustness and efficiency. Two main issues of multirobot exploration are the exploration strategy employed to select the most convenient observation locations the robots should reach in a partially known environment and the coordination method employed to manage the interferences between the actions performed by robots. From the literature, it is difficult to assess the relative effects of these two issues on the system performance. In this paper, we contribute to filling this gap by studying a search and rescue setting in which different coordination methods and exploration strategies are implemented and their contributions to an efficient exploration of indoor environments are comparatively evaluated. Although preliminary, our experimental data lead to the following results: the role of exploration strategies dominates that of coordination methods in determining the performance of an exploring multirobot system in a highly structured indoor environment, while the situation is reversed in a less structured indoor environment.},
	keywords = {coordination, Exploration, multirobot, Search and Rescue},
	isbn = {978-3-642-39250-4},
	doi = {10.1007/978-3-642-39250-4_11},
	url = {http://dx.doi.org/10.1007/978-3-642-39250-4_11},
	author = {Amigoni, Francesco and Basilico, Nicola and Quattrini~Li, Alberto},
	editor = {Chen, Xiaoping and Stone, Peter and Sucar, Luis Enrique and Zant, Tijn}
}
@conference {336,
	title = {Semantically-Informed Coordinated Multirobot Exploration of Relevant Areas in Search and Rescue Settings},
	booktitle = {Proceedings of the 6th European Conference on Mobile Robots (ECMR)},
	year = {2013},
	abstract = {Coordinated multirobot exploration involves autonomous discovering of unknown features in environments by using multiple robots. Autonomously exploring mobile robots are driven by knowledge of the already explored portions of the environment, usually represented in a metric map. In the literature, some works addressed the use of semantic knowledge in exploration, which, embedded in a semantic map, associates spatial concepts (like {\textquoteleft}rooms{\textquoteright} and {\textquoteleft}corridors{\textquoteright}) with metric entities, showing its effectiveness to improve total explored area. In this paper, we build on these results and propose a system that exploits semantic information to push robots to explore areas that are relevant, according to a priori information provided by human users. We tested our semantic-based multirobot exploration system in a reliable robot simulator and evaluated its performance in realistic search and rescue settings with respect to state-of-the-art approaches.},
	doi = {10.1109/ECMR.2013.6698845},
	author = {Riccardo Cipolleschi and Michele Giusto and Quattrini~Li, Alberto and Francesco Amigoni}
}
