Papers by georgios ellinas
Optical Switching and Networking, Nov 1, 2021
For several decades, optical networks, due to their high capacity and long-distance transmission ... more For several decades, optical networks, due to their high capacity and long-distance transmission range, have been used as the major communication technology to serve network traffic, especially in the core and metro segments of communication networks. Unfortunately, our society has often experienced how the correct functioning of these critical infrastructures can be substantially hindered by massive failures triggered by natural disasters, weather-related disruptions and malicious human activities. In this position paper, we discuss the impact on optical networks of all major classes of disaster events mentioned above, and we overview recent relevant techniques that have been proposed to increase the disaster resilience of optical networks against the various classes of disaster events. We start by presenting some proactive methods to be applied before the occurrence of a disaster. Then we move our focus also on other preparedness methods that can be executed in the (typically short) time frame between the occurrence of an early alert of an incoming disaster and the time a disaster actually hits the network. Finally, we discuss reactive procedures that allow performing post-disaster recovery operations effectively. The analysis of disaster resilience mechanisms provided in this paper covers both wired and optical wireless communication infrastructures and also contains explicit remarks covering the role of emerging technologies (e.g., fixed-mobile convergence in the 5G era and beyond) in disaster resilience.
Local optimization of shared backup channels in optical mesh networks
... 2002. [3] JF Labourdette, E. Bouillet, R. Ramamurthy, G. Ellinas, S. Chaudhuri, K. Bala, “Rou... more ... 2002. [3] JF Labourdette, E. Bouillet, R. Ramamurthy, G. Ellinas, S. Chaudhuri, K. Bala, “Routing Strat-egies for Capacity Efficient and Fast Restorable Mesh Optical Networks,” Photonic Network Communications, pp 219-235, July-Dec 2002. ...
Journal of Intelligent and Robotic Systems, Nov 30, 2023
Currently, an unmanned aerial vehicle (UAV) utilizes global navigation satellite systems (GNSS) i... more Currently, an unmanned aerial vehicle (UAV) utilizes global navigation satellite systems (GNSS) in conjunction with other modalities for localization purposes. Nevertheless, this approach faces robustness issues when GNSS signals become unavailable or sensors malfunction. Clearly, the robustness of the system increases considerably when multiple UAV agents are employed to perform collaborative positioning. In this work, an online distributed solution is proposed for relative localization, which incorporates multiple UAVs together with Signals of Opportunity (SOPs) as well as inertial, visual, and optical flow measurements. The proposed localization system includes relative self-localization of each UAV agent, as well as a reliable distributed relative positioning system (DRPS) for each UAV based on the relative positions from other UAV agents in its vicinity. The latter positioning strategy is required in case the relative self-localization fails, mainly due to such problems as inertial measurement unit (IMU) accumulated error drift, camera sensor errors, or SOP shortfalls due to multipath or antenna obstruction. Extensive field experiments validate the proposed technique and demonstrate increased localization accuracy and robustness when compared to the benchmark approach that does not include cooperation between UAVs.
Critical infrastructures (CIs) are large scale systems that are essential for the smooth and reli... more Critical infrastructures (CIs) are large scale systems that are essential for the smooth and reliable operation of everyday activities in modern societies. To understand the operation characteristics of CIs, as well as the behavior of interdependencies between different CIs, we usually use modeling and simulation methodologies. In this work we propose an interdependent CI modeling methodology based on hybrid systems. We adopt open hybrid automata to model the constituent components of different critical infrastructures, including any dependencies that may exist between them. Then, using open hybrid automata composition properties, we can compose different CI component models together, creating a single hybrid automaton model that represents interdependent CIs. Finally, simulating the composition model we can generate sample paths that show how component faults can cascade and/or escalate between CIs.
Reliability Engineering & System Safety, Sep 1, 2017
Critical infrastructure systems (CISs) are large scale and complex systems, across which many int... more Critical infrastructure systems (CISs) are large scale and complex systems, across which many interdependencies exist. As a result, several modeling and simulation approaches are being employed to study the concurrent operation of multiple CISs and their interdependencies. Complementary to existing literature, this work develops and implements a modeling and simulation framework based on open hybrid automata to analyze CISs interdependencies. With the proposed approach, it is possible to develop accurate models of infrastructure components, and interlink them together based on their dependencies; in effect creating larger and more complex models that incorporate interdependencies. By implementing specific setups using varying operating conditions, one can study the cascading effects of interdependencies, perform a detailed vulnerability assessment and conduct an extensive planning exercise. To demonstrate the applicability of the proposed framework, a setup with three different types of CISs (i.e., power, telecom and water) components is investigated. Extensive simulation results are used to provide insights on the cascading effects, vulnerabilities and maintenance planning strategies.
2022 International Conference on Unmanned Aircraft Systems (ICUAS), Jun 21, 2022
Signals of opportunity (SOPs) are a promising technique that can be used for relative positioning... more Signals of opportunity (SOPs) are a promising technique that can be used for relative positioning in areas where global navigation satellite system (GNSS) information is unreliable or unavailable. This technique processes features of the various signals transmitted over a broad wireless spectrum to enable a receiver to position itself in space. This work examines the frequency selection problem in order to achieve fast and accurate positioning using only the received signal strength (RSS) of the surrounding signals. Starting with a prior belief, the problem of searching for a frequency band that best matches a predicted location trajectory is investigated. To maximize the accuracy of the position estimate, a ranking-and-selection problem is mathematically formulated. A knowledge-gradient (KG) algorithm from optimal learning theory is proposed that uses correlations in the Bayesian prior beliefs of the frequency band values to dramatically reduce the algorithm's processing time. The technique is experimentally tested for a practical scenario of an unmanned aerial vehicle (UAV) moving around a GPS-denied environment, with obtained results demonstrating its validity and practical applicability.
An Algorithm for Minimum-Interference Routing in Linear Lightwave Networks
Cambridge University Press eBooks, Jun 19, 2012
Survivable multicast routing in mixed-graph mesh optical WDM networks
Page 1. Survivable Multicast Routing in Mixed-Graph Mesh Optical WDM Networks Costas K. Constanti... more Page 1. Survivable Multicast Routing in Mixed-Graph Mesh Optical WDM Networks Costas K. Constantinou Department of Electrical and Computer Engineering University of Cyprus Nicosia, 1678, Cyprus Email: constantinou.k.costas@ucy.ac.cy ...
The global navigation satellite system (GNSS) is primarily employed for positioning by most moder... more The global navigation satellite system (GNSS) is primarily employed for positioning by most modern navigation systems. However, the application requirements of fully autonomous vehicles cannot be satisfied solely from GNSS and thus a combination of positioning and navigation approaches need to be explored. This work investigates how reliable relative positioning can be achieved in GNSS-challenged application scenarios using a combination of signals of opportunity (SOPs), inertia and vision data. The proposed cooperative relative positioning system (CRPS) exploits this data for real-time positioning, and employs a vehicle tracking algorithm to accurately estimate the vehicle's trajectory in space and time without the use of any GNSS information. Experiments conducted in an outdoor setting demonstrate the applicability of the proposed CRPS and its performance against standalone positioning approaches including GNSS.
2021 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), Sep 27, 2021
We identify the penalties incurred in all-optical networks on routing and restoration operations.... more We identify the penalties incurred in all-optical networks on routing and restoration operations. We show that these penalties can be avoided if we replace the transparent switches with opaque switches interfaced by transponders.
In this work we consider the scheduling problem for charging a fleet of electric vehicles (EVs) w... more In this work we consider the scheduling problem for charging a fleet of electric vehicles (EVs) within a station such that the total tardiness of the problem is minimized. The generation of a feasible and efficient schedule is a difficult task due to the physical and power constraints of the charging station, i.e., the maximum contracted power and the maximum power imbalance between the lines of the electric feeder. The ant colony optimization (ACO) metaheuristic is applied to coordinate the charging process of the EVs within the charging station by generating efficient schedules. The behaviour and performance of ACO is analyzed and compared against state-of-the-art approaches on a benchmark set inspired by real-world scenarios. The experimental results show that the application of ACO is highly effective and outperforms other approaches.
Energy-Aware Tracking and Jamming Rogue UAVs Using a Swarm of Pursuer UAV Agents
IEEE Systems Journal, Mar 1, 2023
OPN08-05: Real-Time Provisioning of Diverse Granularity EVCs in an "All-Ethernet Global MultiService Infrastructure
Globecom, Nov 1, 2006
1. INTRODUCTION Recent dramatic advances in Ethernet and Optical networking technologies fueled b... more 1. INTRODUCTION Recent dramatic advances in Ethernet and Optical networking technologies fueled by Gigabit Ethernet and 10 Gigabit Ethernet are pushing Ethernet footprint into the metro and wide area networks (WANs). The simplicity, low cost, and ubiquitous of Ethernet has ...
Vehicular data offloading under uncertain journey planners
ABSTRACT Self-information broadcast messages are recurrently send out by vehicular terminals to e... more ABSTRACT Self-information broadcast messages are recurrently send out by vehicular terminals to establish their presence and hence improve situational awareness in road transportation. Importantly, such information snippets could prove invaluable to cloud-based intelligent transportation system services that aim to improve safety, traffic efficiency, and offer a plethora of infotainment services. However, due to the bulk nature of the aggregated load collected by vehicular peers, the delivery of this traffic to the infrastructure proves to be a challenging task. The latter offloading problem is considered in this work, in which each individual vehicular station decides on the offloading strategy that maintains proper utilization of the available infrastructure network. For this purpose, a graph theoretic approach is followed in which stations first estimate the potential of eventually being serviced by an available infrastructure node and then decide on the best offloading strategy that minimizes the load variance between the current and subsequent serving nodes. Performance analysis results illustrate that the proposed solution provides substantial load balancing gains and is computationally efficient to implement in practice for arbitrarily large network instances.
Detection and Tracking of Rogue UASs Using a Novel Real-time Passive Radar System
2022 International Conference on Unmanned Aircraft Systems (ICUAS), Jun 21, 2022
Scheduling a Fleet of Drones for Monitoring Missions With Spatial, Temporal, and Energy Constraints
IEEE Transactions on Intelligent Transportation Systems, Sep 1, 2022
Intersection Crossing with Connected Autonomous Vehicles under Location Uncertainty
Intersections are among the most challenging sections of our road infrastructure and a clear bott... more Intersections are among the most challenging sections of our road infrastructure and a clear bottleneck for traffic flows. Key aspects of the 5G cellular network, e.g., the Multi Access Edge Computational (MEC) platform and the reduced network latency, act as enablers for the utilization of Connected Autonomous Vehicles (CAVs) that can ultimately bring about drastic changes in the management of intersection crossings and transportation networks in general. To date, there exist extensive research on the problem of autonomous intersection crossings facilitated by CAVs, but the majority of these works assumes that CAVs know their exact location and system state. This work presents a novel framework that allows for an optimized Intersection Manager (IM) that also considers vehicle location uncertainties. Building upon the proposed optimization framework, AVOID is presented, a real-time, near-optimal algorithm that maximizes intersection throughput with probabilistic collision avoidance guarantees. Extensive simulations assess the performance of AVOID, in terms of safe distance between vehicles and intersection throughput, and the effects of the update communication frequency (from the vehicles to the IM) on the gains of the proposed framework.
Ad hoc networks, Oct 1, 2020
Currently, numerous proprietary communication technologies are used by emergency response personn... more Currently, numerous proprietary communication technologies are used by emergency response personnel to ensure uninterrupted coordination and effective situational awareness, especially when the telecommunication infrastructure gets damaged or destroyed. Affected victims and bystanders, however, lack access to such equipment and are thus deprived of information and unable to reach for help. To ameliorate the situation, this work details a promising networking architecture that capitalizes on beaconing-based technology already available on existing smartphone devices to provide emergency communications. On top of the proposed architecture, intelligent algorithms are developed to support efficient and resilient message exchange for communication and localization among the affected victims; both of which are necessary for prompt and effective response. The paper first provides an analytical performance evaluation of the proposed approach. It then delves into the development and experimentation details that lead to the implementation of a practical application that can be installed and used in time of need. Real-world experiments demonstrate that the proposed algorithms can sustain alert messaging for extended periods of time.
Cyber-Physical Interplay for Data Offloading in Vehicular Networks
IEEE networking letters, Jun 1, 2020
This letter investigates the interplay of the speed-density relationship in transportation system... more This letter investigates the interplay of the speed-density relationship in transportation systems and the density-congestion relationship in communications systems, in terms of the data traffic volume offloaded. It also demonstrates that relaying, when this interplay is also taken into account, greatly enhances the forwarding potentials of vehicular terminals.
Uploads
Papers by georgios ellinas