Publications

2019
D. Popescu, Stoican, F., Stamatescu, G., Chenaru, O., and Ichim, L., “A Survey of Collaborative UAV-WSN Systems for Efficient Monitoring”, SENSORS, vol. 19, 2019.Abstract
Integrated systems based on wireless sensor networks (WSNs) and unmanned aerial vehicles (UAVs) with electric propulsion are emerging as state-of-the-art solutions for large scale monitoring. Main advances stemming both from complex system architectures as well as powerful embedded computing and communication platforms, advanced sensing and networking protocols have been leveraged to prove the viability of this concept. The design of suitable algorithms for data processing, communication and control across previously disparate domains has thus currently become an intensive area of interdisciplinary research. The paper was focused on the collaborative aspects of UAV-WSN systems and the reference papers were analyzed from this point of view, on each functional module. The paper offers a timely review of recent advances in this area of critical interest with focus on a comparative perspective across multiple recent theoretical and applied contributions. A systematic approach is carried out in order to structure a unitary from conceptual design towards key implementation aspects. Focus areas are identified and discussed such as distributed data processing algorithms, hierarchical multi-protocol networking aspects and high level WSN-constrained UAV-control. Application references are highlighted in various domains such as environmental, agriculture, emergency situations and homeland security. Finally, a research agenda is outlined to advance the field towards tangible economic and social impact.
D. Popescu, Ichim, L., Stoican, F., and Dragana, C. - M., “Hierarchical Processing of Signals for Smart Crop Monitoring”, in {8th International Conference on Systems and Control, October 23-25, 2019. Marrakech, Morocco.}, 2019, p. 265–270.
F. Stoican, Popescu, D., and Ichim, L., “Some Comments on the Constrained Trajectory Generation for UAV Systems”, in {27th Mediterranean Conference on Control and Automation July 1 - 4, 2019, Akko, Israel}, 2019.
D. Popescu, Stoican, F., Ichim, L., Stamatescu, G., and Dragana, C., “Collaborative UAV-WSN System for Data Acquisition and Processing in Agriculture”, in 2019 10th IEEE International Conference on Intelligent Data Acquisition and Advanced Computing Systems: Technology and Applications (IDAACS), 2019, vol. 1, p. 519–524.
F. Stoican, Popescu, D., and Ichim, L., “Trajectory Design for Effective and Secure Communication in UAV-WSN Systems”, in 2019 IEEE Radio and Antenna Days of the Indian Ocean (RADIO), 2019, p. 519–524.
2018
D. Popescu, Dragana, C., Stoican, F., Ichim, L., and Stamatescu, G., “A collaborative UAV-WSN network for monitoring large areas”, {S}ensors ({S}witzerland), p. 1-25 (25 pages), 2018.
D. Popescu, Ichim, L., and Stoican, F., “Flooded Area Segmentation from UAV Images Based on Generative Adversarial Networks”, in 15th {I}nternational {C}onference on {C}ontrol, {A}utomation, {R}obotics and {V}ision, {ICARCV} 2018, 2018, p. 1361-1366 (6 pages).
F. Stoican, Popescu, D., and Ichim, L., “A Geometrical Interpretation of Communication Restrictions in a Multi-Agent Environment”, in 2018 {IEEE} {R}adio and {A}ntenna {D}ays of the {I}ndian {O}cean, {RADIO} 2018, 2018, p. 1-2 (2 pages).
F. Stoican, Prodan, I., Popescu, D., Ichim, L., and Vlsceanu, E., “Mixed-Integer Representations for Mission Constraints in a Multi-Agent Team”, in 15th {I}nternational {C}onference on {C}ontrol, {A}utomation, {R}obotics and {V}ision, {ICARCV} 2018, 2018, p. 562-567 (6 pages).
2017
F. Stoican, Prodan, I., Popescu, D., and Ichim, L., “Constrained trajectory generation for UAV systems using a B-spline parametrization”, in 25th {M}editerranean {C}onference on {C}ontrol and {A}utomation, {MED} 2017, 2017, p. 613-618 (6 pages).
O. Chenaru, Popescu, D., Enache, D., Ichim, L., and Stoican, F., “Improving operational security for web-based distributed control systems in wastewater management”, in 25th {M}editerranean {C}onference on {C}ontrol and {A}utomation, {MED} 2017, 2017, p. 1089-1093 (5 pages).
D. Popescu, Ichim, L., and Stoican, F., “Unmanned aerial vehicle systems for remote estimation of flooded areas based on complex image processing”, {S}ensors ({S}witzerland), p. 1-24 (24 pages), 2017.
2016
D. Popescu, Ichim, L., Gornea, D., and Stoican, F., “Complex Image Processing Using Correlated Color Information”, in Advanced Concepts for Intelligent Vision Systems (ACIVS 2016), Lecce, Italy, 2016, p. 723-734.Abstract
The paper presents a method for patch classification and remoteimage segmentation based on correlated color information. During the trainingphase, a supervised learning algorithm is considered. In the testing phase, weused the classifier built a priori to predict which class an input image samplebelongs to. The tests showed that the most relevant features are contrast, energyand homogeneity extracted from the co-occurrence matrix between H and Scomponents. Compared to gray-level, the chromatic matrices improve the processof texture classification. For experimental results, the images were acquiredby the aid of an unmanned aerial vehicle and represent various types of terrain.Two case studies have shown that the proposed method is more effective thanconsidering separate color channels: flooded area and road segmentation. Also it is shown that the new algorithm provides a faster execution time than the similar one proposed.
D. Popescu, Stoican, F., and Ichim, L., “Control and Optimization of UAV Trajectory for Aerial Coverage in Photogrammetry Applications”, Advances in Electrical and Computer Engineering, vol. 16, no. 3, p. 99-106, 2016.Abstract
Photogrammetry is a well-studied and much-used analysis tool. Typical use cases include area surveillance, flood monitoring and related tasks. Usually, an Unmanned Aerial System (UAS) is used as support for image acquisition from an a priori delimited region in a semi-automated manner (via a mix of ground control and autonomous trajectory tracking). This in turn has led to various algorithms which handle path trajectory generation under realistic constraints but still many avenues remain open. In this paper, we consider typical costs and constraints (UAS dynamics, total-path length, line inter-distance, turn points, etc.) in order to obtain, via optimization procedures, an optimal trajectory. To this end we make use of polyhedral set operations, flat trajectory generation and other similar tools. Additional work includes the study of non-convex regions and estimation of the number of photographs taken via Ehrhart polynomial computations.
F. Stoican, Ivanusca, V. - M., Prodan, I., and Popescu, D., “Obstacle avoidance via B-spline parametrizations of flat trajectories”, in 24th Mediterranean Conference on Control and Automation (MED), Athens, Greece, 2016.Abstract
This paper considers the collision avoidance problem in a multi-agent multi-obstacle framework. The originality in solving this intensively studied problem resides in the proposed geometrical view combined with differential flatness for trajectory generation and B-splines for the flat output parametrization. Using some important properties of these theoretical tools we show that the constraints can be validated at all times. Exact and sub-optimal constructions of the collision avoidance optimization problem are provided. The results are validated through extensive simulations over standard autonomous aerial vehicle dynamics.
2015
Trajectory Generation with Way-Point Constraints for UAV Systems
F. Stoican and Popescu, D., “Trajectory Generation with Way-Point Constraints for UAV Systems”, in Advances in Robot Design and Intelligent Control, vol. 371, Springer, 2015, p. 379-386.Abstract
This paper addresses some alternatives to classical trajectory generation for an unmanned aerial vehicle (UAV) which needs to pass through (or near) a priori given way-points. Using differential flatness for trajectory generation and B-splines for the flat output parameterization, the current study concentrates on flat descriptions which respect to UAV dynamics and verify way-point constraints.
2014
F. Stoican, Prodan, I., Strutu, M. - I., and Popescu, D., “Geometrical interpretation on the coverage problems for a mobile agent”, in 18th International Conference on System Theory, Control and Computing, Sinaia, Romania, 2014.
2013
M. - I. Strutu, Stoican, F., Prodan, I., Popescu, D., and Olaru, S., “A characterization of the relative positioning of mobile agents for full sensorial coverage in an augmented space with obstacles”, in Proceedings of the 21st Mediterranean Conference on Control and Automation, Platania-Chania, Crete, Grecee, 2013, p. 936-941.Abstract
This paper addresses the coverage problem for a collection of agents and fixed obstacles (e.g., the “gallery” and the “patrolling” problems). A collection of sufficient conditions over the positions of the agents are provided such that whenever these are verified there is no “blind” region in the feasible space. These conditions are expressed by making use of hyperplane arrangements which lead to a mixed-integer formulation. Practical applications regarding the coverage problem inside an augmented space with obstacles validate these concepts and provide an efficient implementation (in terms of computing power).