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Wang, F. (author), Kooij, R.E. (author)Network controllability and its robustness have been widely studied. However, analytical methods to calculate network controllability with respect to node in- and out-degree targeted removals are currently lacking. This paper develops methods, based on generating functions for the in- and out-degree distributions, to approximate the minimum...article 2023
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Liu, X. (author), Achterberg, M.A. (author), Kooij, R.E. (author)pinion dynamics models study how the interaction among people influences the opinion formation process. In most opinion dynamics models, only one opinion can exist in the steady state, which is different from the real-life opinion formation process. In 2009, Shao et at. introduced a Non-Consensus Opinion (NCO) model, which allows different...conference paper 2022
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Kumaresan, A. (author), Kandasamy, N.K. (author), Kooij, R.E. (author)The endeavour towards making power distribution systems (PDSs) smarter has made the interdependence on communication network indispensable. Further, prospective high penetration of intermittent renewable energy sources in the form of distributed energy resources (DERs) has resulted in the necessity for smart controllers on such DERs. Inverters...article 2022
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- Wang, X. (author), Koç, Y. (author), Derrible, S. (author), Ahmad, S.N. (author), Pino, W.J.A. (author), Kooij, R.E. (author) article 2017
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Wang, X. (author), Trajanovski, S. (author), Kooij, R.E. (author), van Mieghem, P. (author)Topological characteristics of links of complex networks influence the dynamical processes executed on networks triggered by links, such as cascading failures triggered by links in power grids and epidemic spread due to link infection. The line graph transforms links in the original graph into nodes. In this paper, we investigate how graph...article 2016
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Wang, X. (author), Kooij, R.E. (author), van Mieghem, P. (author)Various real-world networks interact with and depend on each other. The design of the interconnection between interacting networks is one of the main challenges to achieve a robust interdependent network. Due to cost considerations, network providers are inclined to interconnect nodes that are geographically close. Accordingly, we propose two...article 2016
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Wang, X. (author), Koç, Y. (author), Kooij, R.E. (author), van Mieghem, P. (author)Cascading failures are one of the main reasons for blackouts in electrical power grids. Stable power supply requires a robust design of the power grid topology. Currently, the impact of the grid structure on the grid robustness is mainly assessed by purely topological metrics, that fail to capture the fundamental properties of the electrical...conference paper 2015
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Verma, T. (author), Ellens, W. (author), Kooij, R.E. (author)Power grids vulnerability is a key issue in society. A component failure may trigger cascades of failures across the grid and lead to a large blackout. Within complex network analysis, structural vulnerabilities of power grids have been studied mostly using purely topological approaches, which assumes that flow of power is dictated by shortest...article 2015
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Brown, J.I. (author), Koç, Y. (author), Kooij, R.E. (author)Given a finite, undirected graph G (possibly with multiple edges), we assume that the vertices are operational, but the edges are each independently operational with probability p. The (all-terminal) reliability, Rel(G,p), of G is the probability that the spanning subgraph of operational edges is connected. It has been conjectured that...article 2014
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Pournaras, E. (author), Vasirani, M. (author), Kooij, R.E. (author), Aberer, K. (author)Demand-side energy management improves robustness and efficiency in Smart Grids. Load-adjustment and load-shifting are performed to match demand to available supply. These operations come at a discomfort cost for consumers as their lifestyle is influenced when they adjust or shift in time their demand. Performance of demand-side energy...conference paper 2014
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Koç, Y. (author), Warnier, M. (author), van Mieghem, P. (author), Kooij, R.E. (author), Brazier, F.M.T. (author)Cascading failures are one of the main reasons for blackouts in electric power transmission grids. The economic cost of such failures is in the order of tens of billion dollars annually. The loading level of power system is a key aspect to determine the amount of the damage caused by cascading failures. Existing studies show that the blackout...article 2014
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Koç, Y. (author), Warnier, M. (author), Kooij, R.E. (author), Brazier, F. (author)Cascading failures are the typical reasons of blackouts in power grids. The grid topology plays an important role in determining the dynamics of cascading failures in power grids. Measures for vulnerability analysis are crucial to assure a higher level of robustness of power grids. Metrics from Complex Networks are widely used to investigate the...conference paper 2014
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Pournaras, E. (author), Vasirani, M. (author), Kooij, R.E. (author), Aberer, K. (author)The robustness of smart grids is challenged by unpredictable power peaks or temporal demand oscillations that can cause blackouts and increase supply costs. Planning of demand can mitigate these effects and increase robustness. However, the impact on consumers in regards to the discomfort they experience as a result of improving robustness is...article 2014
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Ouboter, T.M. (author), Worm, D.T.H. (author), Kooij, R.E. (author), Wang, H. (author)In this paper we propose strategies to increase the robustness of a communication network which depends on the proper functioning of an electricity network. The strategies involve selecting nodes of the communication network and removing their dependency on the electricity network. Compared to existing literature on this topic, such as Schneider...conference paper 2014
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Veltman, M. (author), Kooij, R.E. (author), Marban, S. (author)This study introduces the term sales bottleneck, defined as a stage in a total production or service delivery process that limits sales. After analyzing the suitability of traditional methods to find sales bottlenecks, the study proposes the bottleneck accounting model as a method to determine sales bottlenecks and calculate the effect of each...article 2014
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- Wang, X. (author), Pournaras, E. (author), Kooij, R.E. (author), van Mieghem, P. (author) article 2014
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Koç, Y. (author), Warnier, M. (author), van Mieghem, P. (author), Kooij, R.E. (author), Brazier, F.M.T. (author)Cascading failures are one of the main reasons for large scale blackouts in power transmission grids. Secure electrical power supply requires, together with careful operation, a robust design of the electrical power grid topology. Currently, the impact of the topology on grid robustness is mainly assessed by purely topological approaches, that...article 2014
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Koc, Y. (author), Warnier, M. (author), Kooij, R.E. (author), Brazier, F.M.T. (author)Cascading failures are the main reason blackouts occur in power networks. The economic cost of such failures is in the order of tens of billion dollars annually. In a power network, the cascading failure phenomenon is related to both topological properties (number and types of buses, density of transmission lines and interconnection of...conference paper 2013
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Ellens, W. (author), Kooij, R.E. (author)Network robustness research aims at finding a measure to quantify network robustness. Once such a measure has been established, we will be able to compare networks, to improve existing networks and to design new networks that are able to continue to perform well when it is subject to failures or attacks. In this paper we survey a large amount of...article 2013
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Koç, Y. (author), Warnier, M. (author), Kooij, R.E. (author), Brazier, F.M.T. (author)The cascading failure phenomenon in a power grid is related to both the structural aspects (number and types of buses, density of transmission lines and interconnection of components), and the operative state (flow distribution and demand level). Existing studies most often focus on structural aspects, and not on operative states. This paper...article 2013