| 1. |
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| 2. |
- Alfonsetti, Elisabetta, et al.
(författare)
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Min-max fair car-parking slot assignment
- 2015
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Ingår i: Proceedings of the WoWMoM 2015. - : IEEE conference proceedings. - 9781479984619
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Konferensbidrag (refereegranskat)abstract
- Empirical studies show that cruising for car parking accounts for a non-negligible amount of the daily traffic, especially in central areas of large cities. Therefore, mechanisms for minimizing traffic from cruising directly affect the dynamics of traffic congestions. One way to minimizing cruising traffic is efficient car-parking-slot assignment. Usually, the related design problems are combinatorial and the worst-case complexity of optimal methods grows exponentially with the problem sizes. As a result, almost all existing methods for parking slot assignment are simple and greedy approaches, where each car or the user is assigned a free parking slot, which is closer to its destination. Moreover, no emphasis is placed to optimize any form of fairness among the users as the a social benefit. In this paper, the fairness as a metric for modeling the aggregate social benefit of the users is considered. An algorithm based on Lagrange duality is developed for car-parking-slot assignment. Numerical results illustrate the performance of the proposed algorithm compared to the optimal assignment and a greedy method.
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| 3. |
- Cucuzzella, M., et al.
(författare)
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Distributed Control of DC Grids : Integrating Prosumers' Motives
- 2022
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Ingår i: IEEE Transactions on Power Systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 0885-8950 .- 1558-0679. ; 37:4, s. 3299-3310
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, a novel distributed control strategy addressing a (feasible) psycho-social-physical welfare problem in islanded Direct Current (DC) smart grids is proposed. Firstly, we formulate a (convex) optimization problem that allows prosumers to share current with each other, taking into account the technical and physical aspects and constraints of the grid (e.g., stability, safety), as well as psycho-social factors (i.e., prosumers' personal values). Secondly, we design a controller whose (unforced) dynamics represent the continuous time primal-dual dynamics of the considered optimization problem. Thirdly, a passive interconnection between the physical grid and the controller is presented. Global asymptotic convergence of the closed-loop system to the desired steady-state is proved and simulations based on collected data on psycho-social aspects illustrate and confirm the theoretical results.
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| 4. |
- da Silva, Joakim M. B., et al.
(författare)
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Energy-efficient full-duplex networks
- 2020
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Ingår i: Green Communications for Energy-Efficient Wireless Systems and Networks. - : Institution of Engineering and Technology. ; , s. 331-362
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 5. |
- Ergen, S. C., et al.
(författare)
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MAC protocol engine for sensor networks
- 2009
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Ingår i: GLOBECOM - IEEE Global Telecommunications Conference. - 9781424441471
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Konferensbidrag (refereegranskat)abstract
- We present a novel approach for Medium Access Control (MAC) protocol design based on protocol engine. Current way of designing MAC protocols for a specific application is based on two steps: First the application specifications (such as network topology and packet generation rate), the requirements for energy consumption, delay and reliability, and the resource constraints from the underlying physical layer (such as energy consumption and data rate) are specified, and then the protocol that satisfies all these constraints is designed. Main drawback of this procedure is that we have to restart the design process for each possible application, which may be a waste of time and efforts. The goal of a MAC protocol engine is to provide a library of protocols together with their analysis such that for each new application the optimal protocol is chosen automatically among its library with optimal parameters. We illustrate the MAC engine idea by including an original analysis of IEEE 802.15.4 unslotted random access and Time Division Multiple Access (TDMA) protocols, and implementing these protocols in the software framework called SPINE, which runs on top of TinyOS and is designed for health care applications. Then we validate the analysis and demonstrate how the protocol engine chooses the optimal protocol under different application scenarios via an experimental implementation.
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| 6. |
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| 7. |
- Kalalas, C., et al.
(författare)
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Enabling IEC 61850 communication services over public LTE infrastructure
- 2016
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Ingår i: 2016 IEEE International Conference on Communications, ICC 2016. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781479966646
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Konferensbidrag (refereegranskat)abstract
- Ongoing IEC 61850 standardization activities aim at improved grid reliability through advanced monitoring and remote control services in medium- and low-voltage. However, extending energy automation beyond the substation boundaries introduces the need for timely and reliable information exchange over wide areas. LTE appears as a promising solution since it supports extensive coverage, low latency, high throughput and Quality-of-Service (QoS) differentiation. In this paper, the feasibility of implementing IEC 61850 services over public LTE infrastructure is investigated. Since standard LTE cannot meet the stringent latency requirements of such services, a new LTE QoS class is introduced along with a new LTE scheduler that prioritizes automation traffic with respect to background human-centric traffic. Two representative grid automation services are considered, a centralized (MMS) and a distributed one (GOOSE), and the achievable latency/throughput performance is evaluated on a radio system simulator platform. Simulations of realistic overload scenarios demonstrate that properly designed LTE schedulers can successfully meet the performance requirements of IEC 61850 services with negligible impact on background traffic.
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| 8. |
- Millán, P., et al.
(författare)
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Distributed event-based observers for LTI systems
- 2015
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Ingår i: Asynchronous Control for Networked Systems. - Cham : Springer Publishing Company. - 9783319212982 ; , s. 181-191
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter is concerned with the networked distributed estimation problem. A set of agents (observers) are assumed to be estimating the state of a large-scale process. Each of them must provide a reliable estimate of the state of the plant, but it have only access to some plant outputs. Local observability is not assumed, so the agents need to communicate and collaborate to obtain their estimates. This chapter proposes a structure of the observers, which merges local Luenberger-like estimators with consensus matrices.
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| 9. |
- Möller, Niels, et al.
(författare)
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Modeling and control of IP transport in cellular radio links
- 2005
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Konferensbidrag (refereegranskat)abstract
- A fundamental assumption of the TCP protocol is that packet losses indicate congestion on the network. This is a problem when using TCP over wireless links, because a noisy radio transmission may erroneously indicate congestion and thereby reduce the TCP sending rate. Two partial solutions, which improve the quality of the radio link, are power control and link-layer retransmissions. We consider a radio channel with multiple users and traffic classes, and investigate how parameters in the radio model influences TCP-related quality measures, such as the average delay and the probability of spurious timeout. The results indicate that the outer loop power control is robust to uncertainties in the radio model. This robustness property supports separation between the radio layer design and the IP and TCP layers.
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| 10. |
- Park, P., et al.
(författare)
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Duty-cycle optimization for IEEE 802.15.4 wireless sensor networks
- 2013
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Ingår i: ACM Transactions on Sensor Networks. - : Association for Computing Machinery (ACM). - 1550-4859 .- 1550-4867. ; 10:1, s. 12-
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Tidskriftsartikel (refereegranskat)abstract
- Most applications of wireless sensor networks require reliable and timely data communication with maximum possible network lifetime under low traffic regime. These requirements are very critical especially for the stability of wireless sensor and actuator networks. Designing a protocol that satisfies these requirements in a network consisting of sensor nodes with traffic pattern and location varying over time and space is a challenging task. We propose an adaptive optimal duty-cycle algorithm running on top of the IEEE 802.15.4 medium access control tominimize power consumption while meeting the reliability and delay requirements. Such a problem is complicated because simple and accurate models of the effects of the duty cycle on reliability, delay, and power consumption are not available. Moreover, the scarce computational resources of the devices and the lack of prior information about the topology make it impossible to compute the optimal parameters of the protocols. Based on an experimental implementation, we propose simple experimental models to expose the dependency of reliability, delay, and power consumption on the duty cycle at the node and validate it through extensive experiments. The coefficients of the experimental-based models can be easily computed on existing IEEE 802.15.4 hardware platforms by introducing a learning phase without any explicit information about data traffic, network topology, and medium access control parameters. The experimental-based model is then used to derive a distributed adaptive algorithm for minimizing the power consumption while meeting the reliability and delay requirements in the packet transmission. The algorithm is easily implementable on top of the IEEE 802.15.4 medium access control without any modifications of the protocol. An experimental implementation of the distributed adaptive algorithm on a test bed with off-the-shelf wireless sensor devices is presented. The experimental performance of the algorithms is compared to the existing solutions from the literature. The experimental results show that the experimentalbased model is accurate and that the proposed adaptive algorithm attains the optimal value of the duty cycle, maximizing the lifetime of the network while meeting the reliability and delay constraints under both stationary and transient conditions. Specifically, even if the number of devices and their traffic configuration change sharply, the proposed adaptive algorithm allows the network to operate close to its optimal value. Furthermore, for Poisson arrivals, the duty-cycle protocol is modeled as a finite capacity queuing system in a star network. This simple analytical model provides insights into the performance metrics, including the reliability, average delay, and average power consumption of the duty-cycle protocol.
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| 11. |
- Rinaldi, C., et al.
(författare)
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Hybrid model of least squares handover algorithms in wireless networks
- 2007
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Ingår i: IEEE Vehicular Technology Conference. ; , s. 3106-3110
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Konferensbidrag (refereegranskat)abstract
- An adaptive handover algorithm for wireless communication systems is addressed in this paper. Moving from the Generalized Extended Least Square handover algorithm proposed in [1], we model the handover mechanism as a hybrid system, and we include it in a dynamic optimization problem which is solved through the use of a trellis diagram. The objective function takes into account the parameters that influence the handover mechanism. The optimal solution of the program allows to evaluate performance of the handover in terms of the probability of handover and probability of outage.
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| 12. |
- Weeraddana, P. C., et al.
(författare)
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On the Privacy of Optimization
- 2017
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Ingår i: IFAC-PapersOnLine. - : Elsevier. - 2405-8963. ; 50:1, s. 9502-9508
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Tidskriftsartikel (refereegranskat)abstract
- In distributed or multiparty computations, optimization theory methods offer appealing privacy properties compared to cryptography and differential privacy methods. However, unlike cryptography and differential privacy, optimization methods currently lack a formal quantification of the privacy they can provide. The main contribution of this paper is to propose a quantification of the privacy of a broad class of optimization approaches. The optimization procedures generate a problem's data ambiguity for an adversarial observer, which thus observes the problem's data within an uncertainty set. We formally define a one-to-many relation between a given adversarial observed message and an uncertainty set of the problem's data. Based on the uncertainty set, a privacy measure is then formalized. The properties of the proposed privacy measure are analyzed. The key ideas are illustrated with examples, including localization and average consensus.
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| 13. |
- Xu, Yuzhe, et al.
(författare)
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A Semi Distributed Approach for Feasible Min-Max Fair Agent-assignment Problem with Privacy Guarantees
- 2016
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Ingår i: IEEE Transactions on Control of Network Systems. - : IEEE Press. - 2325-5870. ; PP:99
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Tidskriftsartikel (refereegranskat)abstract
- In cyberphysical systems, a relevant problem is assigning agents to slots by distributed decisions capable to preserve agent's privacy. For example, in future intelligent transportation systems, city-level coordinators may optimally assign cars (the agents) to parking slots depending on the cars' distance to final destinations so to ensuring social fairness and without disclosing or even using the car's destination information. Unfortunately, these assignment problems are combinatorial, whereas traditional solvers are exponentially complex, are not scalable, and do not ensure privacy of the agents' intended destinations. Moreover, no emphasis is placed to optimise the agents' social benefit. In this paper, the aggregate social benefit of the agents is considered by an agent-slot assignment optimization problem whose objective function is the fairness among the agents. Due to the problem's complexity, the problem is solved by an approximate approach based on Lagrange duality theory that allows to develop an iterative semi-distributed algorithm. It is shown that the proposed algorithm is gracefully scalable compared to centralised methods, and that it preserves privacy in the sense that an eavesdropper will not be able to discover the destination of any agent during the algorithm iterations. Numerical results illustrate the performance and trade-off of the proposed algorithm compared to the ideal optimal assignment and a greedy method.
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