| 1. |
- Yang, Tao, et al.
(författare)
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A survey of distributed optimization
- 2019
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Ingår i: Annual Reviews in Control. - : PERGAMON-ELSEVIER SCIENCE LTD. - 1367-5788 .- 1872-9088. ; 47, s. 278-305
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Forskningsöversikt (refereegranskat)abstract
- In distributed optimization of multi-agent systems, agents cooperate to minimize a global function which is a sum of local objective functions. Motivated by applications including power systems, sensor networks, smart buildings, and smart manufacturing, various distributed optimization algorithms have been developed. In these algorithms, each agent performs local computation based on its own information and information received from its neighboring agents through the underlying communication network, so that the optimization problem can be solved in a distributed manner. This survey paper aims to offer a detailed overview of existing distributed optimization algorithms and their applications in power systems. More specifically, we first review discrete-time and continuous-time distributed optimization algorithms for undirected graphs. We then discuss how to extend these algorithms in various directions to handle more realistic scenarios. Finally, we focus on the application of distributed optimization in the optimal coordination of distributed energy resources.
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| 2. |
- Yang, Tao, et al.
(författare)
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Cooperative Optimal Coordination for Distributed Energy Resources
- 2017
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Ingår i: 2017 IEEE 56TH ANNUAL CONFERENCE ON DECISION AND CONTROL (CDC). - : IEEE. - 9781509028733 ; , s. 6334-6339
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Konferensbidrag (refereegranskat)abstract
- In this paper, we consider the optimal coordination problem for distributed energy resources (DERs) including distributed generators and energy storage devices. We propose an algorithm based on the push-sum and gradient method to optimally coordinate distributed generators and storage devices in a distributed manner. In the proposed algorithm, each DER only maintains a set of variables and updates them through information exchange with a few neighbors over a time-varying directed communication network. We show that the proposed distributed algorithm solves the optimal DER coordination problem if the time-varying directed communication network is uniformly jointly strongly connected, which is a mild condition on the connectivity of communication topologies. The proposed distributed algorithm is illustrated and validated by numerical simulations.
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| 3. |
- Yang, Tao, et al.
(författare)
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Distributed Energy Resource Coordination Over Time-Varying Directed Communication Networks
- 2019
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Ingår i: IEEE Transactions on Control of Network Systems. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 2325-5870. ; 6:3, s. 1124-1134
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we consider the optimal coordination problem for distributed energy resources (DERs), including distributed generators and energy storages. We first propose an algorithm based on the push-sum and gradient method to solve the optimal DER coordination problem in a distributed manner. In the proposed algorithm, each DER only maintains a set of variables and updates them through information exchange with a few neighboring DERs over a time-varying directed communication network. We show that the proposed distributed algorithm with appropriately chosen diminishing step sizes solves the optimal DER coordination problem if the time-varying directed communication network is uniformly jointly strongly connected. Moreover, in order to improve the convergence speed and to reduce the communication burden, we propose an accelerated distributed algorithm with a fixed step size. We show that the new proposed algorithm exponentially solves the optimal DER coordination problem if the cost functions satisfy an additional assumption and the selected step size is less than a certain critical value. Both proposed distributed algorithms are validated and evaluated using the IEEE 39-bus system.
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| 4. |
- Bernardo, Carmela, et al.
(författare)
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Achieving consensus in multilateral international negotiations : The case study of the 2015 Paris Agreement on climate change
- 2021
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Ingår i: Science Advances. - : American Association for the Advancement of Science.. - 2375-2548. ; 7:51
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this paper is to propose a dynamical model describing the achievement of the 2015 Paris Agreement on climate change. To represent the complex, decade-long, multiparty negotiation process that led to the accord, we use a two time scale dynamical model. The short time scale corresponds to the discussion process occurring at each meeting and is represented as a Friedkin-Johnsen model, a dynamical multiparty model in which the parties show stubbornness, i.e., tend to defend their positions during the discussion. The long time scale behavior is determined by concatenating multiple Friedkin-Johnsen models (one for each meeting). The proposed model, tuned on real data extracted from the Paris Agreement meetings, achieves consensus on a time horizon similar to that of the real negotiations. Remarkably, the model is also able to identify a series of parties that exerted a key leadership role in the Paris Agreement negotiation process.
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| 5. |
- Chen, Ziqin, et al.
(författare)
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Defense for Advanced Persistent Threat with Inadvertent and Malicious Insider Threats
- 2024
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Ingår i: Unmanned Systems. - : World Scientific Pub Co Pte Ltd. - 2301-3850 .- 2301-3869. ; 12:2, s. 341-358
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we propose a game theory framework to solve advanced persistent threat problems, especially considering two types of insider threats: malicious and inadvertent. Within this framework, we establish a unified three-player game model and derive Nash equilibria in response to different types of insider threats. By analyzing these Nash equilibria, we provide quantitative solutions to advanced persistent threat problems pertaining to insider threats. Furthermore, we have conducted a comparative assessment of the optimal defense strategy and corresponding defender’s costs between two types of insider threats. Interestingly, our findings advocate a more proactive defense strategy against inadvertent insider threats in contrast to malicious ones, despite the latter imposing a higher burden on the defender. Our theoretical results are substantiated by numerical results, which additionally include a detailed exploration of the conditions under which different insiders adopt risky strategies. These conditions can serve as guiding indicators for the defender when calibrating their monitoring intensities and devising defensive strategies.
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| 6. |
- Cheng, Zhaoyang, et al.
(författare)
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Equalizer Zero-Determinant Strategy in Discounted Repeated Stackelberg Asymmetric Game
- 2024
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Ingår i: Journal of Systems Science and Complexity. - : Springer Nature. - 1009-6124 .- 1559-7067. ; 37:1, s. 184-203
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Tidskriftsartikel (refereegranskat)abstract
- This paper focuses on the performance of equalizer zero-determinant (ZD) strategies in discounted repeated Stackelberg asymmetric games. In the leader-follower adversarial scenario, the strong Stackelberg equilibrium (SSE) deriving from the opponents’ best response (BR), is technically the optimal strategy for the leader. However, computing an SSE strategy may be difficult since it needs to solve a mixed-integer program and has exponential complexity in the number of states. To this end, the authors propose an equalizer ZD strategy, which can unilaterally restrict the opponent’s expected utility. The authors first study the existence of an equalizer ZD strategy with one-to-one situations, and analyze an upper bound of its performance with the baseline SSE strategy. Then the authors turn to multi-player models, where there exists one player adopting an equalizer ZD strategy. The authors give bounds of the weighted sum of opponents’s utilities, and compare it with the SSE strategy. Finally, the authors give simulations on unmanned aerial vehicles (UAVs) and the moving target defense (MTD) to verify the effectiveness of the proposed approach.
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| 7. |
- Cheng, Zhaoyang, et al.
(författare)
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Zero-determinant strategy in stochastic Stackelberg asymmetric security game
- 2023
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Ingår i: Scientific Reports. - : Nature Research. - 2045-2322. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- In a stochastic Stackelberg asymmetric security game, the strong Stackelberg equilibrium (SSE) strategy is a popular option for the defender to get the highest utility against an attacker with the best response (BR) strategy. However, the attacker may be a boundedly rational player, who adopts a combination of the BR strategy and a fixed stubborn one. In such a condition, the SSE strategy may not maintain the defensive performance due to the stubbornness. In this paper, we focus on how the defender can adopt the unilateral-control zero-determinate (ZD) strategy to confront the boundedly rational attacker. At first, we verify the existence of ZD strategies for the defender. We then investigate the performance of the defender’s ZD strategy against a boundedly rational attacker, with a comparison of the SSE strategy. Specifically, when the attacker’s strategy is close to the BR strategy, the ZD strategy admits a bounded loss for the defender compared with the SSE strategy. Conversely, when the attacker’s strategy is close to the stubborn strategy, the ZD strategy can bring higher defensive performance for the defender than the SSE strategy does.
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| 8. |
- Fontan, Angela, 1991-, et al.
(författare)
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Multiagent Consensus over Time-Invariant and Time-Varying Signed Digraphs via Eventual Positivity
- 2023
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Ingår i: IEEE Transactions on Automatic Control. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9286 .- 1558-2523. ; 68:9, s. 5429-5444
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Tidskriftsartikel (refereegranskat)abstract
- Laplacian dynamics on signed digraphs have a richer behavior than those on nonnegative digraphs. In particular, for the so-called 'repelling' signed Laplacians, the marginal stability property (needed to achieve consensus) is not guaranteed a priori and, even when it holds, it does not automatically lead to consensus, as these signed Laplacians may lose rank even in strongly connected digraphs. Furthermore, in the time-varying case, instability can occur even when switching in a family of systems each of which corresponds to a marginally stable signed Laplacian with the correct corank. In this article, we present novel conditions for achieving consensus on signed digraphs based on the property of eventual positivity, a Perron-Frobenius (PF) type of property for signed matrices. The conditions we develop cover both time-invariant and time-varying cases. A particularly simple sufficient condition, valid in both cases, is that the Laplacians are normal matrices. Such condition can be relaxed in several ways. For instance, in the time-invariant case it is enough that the Laplacian has this PF property on the right side, but not on the left side (i.e., on the transpose). For the time-varying case, convergence to consensus can be guaranteed by the existence of a common Lyapunov function for all the signed Laplacians. All conditions can be easily extended to bipartite consensus.
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| 9. |
- He, Xingkang, et al.
(författare)
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Distributed Kalman Filters With State Equality Constraints : Time-Based and Event-Triggered Communications
- 2020
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Ingår i: IEEE Transactions on Automatic Control. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0018-9286 .- 1558-2523. ; 65:1, s. 28-43
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we investigate a distributed estimation problem for multiagent systems with state equality constraints (SEC). First, under a time-based consensus communication protocol, applying a modified projection operator and the covariance intersection fusion method, we propose a distributed Kalman filter with guaranteed consistency and satisfied SEC. Furthermore, we establish the relationship between consensus step, SEC, and estimation error covariance in dynamic and steady processes, respectively. Employing a space decomposition method, we show that the error covariance in the constraint set can be arbitrarily small by setting a sufficiently large consensus step. Besides, we propose an extended collective observability (ECO) condition based on SEC, which is milder than existing observability conditions. Under the ECO condition, through utilizing a technique of matrix approximation, we prove the boundedness of error covariance and the exponentially asymptotic unbiasedness of state estimate, respectively. Moreover, under the ECO condition for linear time-invariant systems with SEC, we provide a novel event-triggered communication protocol by employing the consistency, and give an offline design principle of triggering thresholds with guaranteed boundedness of error covariance. More importantly, we quantify and analyze the communication rate for the proposed event-triggered distributed Kalman filter, and provide optimization based methods to obtain the minimal (maximal) successive nontriggering (triggering) times. Two simulations are provided to demonstrate the developed theoretical results and the effectiveness of the filters.
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| 10. |
- Hu, Jiangping, et al.
(författare)
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Distributed dynamic control for leaderless multi-agent consensus with star-like topology
- 2008
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Ingår i: Asian Journal of Control. - : Wiley. - 1561-8625 .- 1934-6093. ; 10:2, s. 233-237
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we consider a consensus problem of a group of mobile agents interconnected by a star-like topology. Not all the state variables of the agent in the center of the group are available for its neighbors. A distributed controller together with a local state-estimation rule is given for each agent who has to estimate the unmeasurable velocity. Then, with help of virtual equivalent agents, we prove that, with the proposed control scheme, the group of agents can reach its consensus.
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