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This paper addresses the development, testing and implementation of a fast automated process for assessing power system performance following loss of two bulk transmission elements consecutively (N-1-1 contingency analysis) and simultaneously (N-2 contingency analysis). The approach described in this paper offers a flexibility to utilize various sets of system adjustments depending on types and values of postcontingency limit violations. It also incorporates sequential contingency simulation in order to identify potential cascading modes due to thermal overloads. Massive AC contingency analysis, automatically identifying various sets of system adjustments and prediction of cascades are performed within one computational run. The proposed process is utilized as a part of Midwest ISO's NERC-compliance studies. Flexible reporting ensures that the obtained results are seamlessly integrated into the Midwest ISO's existing reliability results database. This approach may be used by ISOs and utilities as a part of their compliance studies to assess and improve the reliability of a transmission grid and reduce its vulnerability to cascading outages.

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The Internet-of-Things (IoT) emerges as a paradigm to achieve ubiquitous connectivity via wireless communications between kinds of physical objects. Due to the wireless broadcasting nature and the energy constraint of physical objects, concerns on IoT security have triggered research on cooperative jamming based physical layer security. With the help of a cooperative jammer, existing solutions can effectively fight against eavesdroppers. However, these schemes are of high energy cost due to continuously transmitting jamming signals. To reduce the energy consumption, we propose a new idea of intermittent jamming and design five specific intermittent jamming schemes (IJSs). By taking the transmit frame formate into account, we optimize these IJSs from three aspects, including the jamming power, the jamming method, and the jamming positions. Then we analyze the applicability of the proposed IJSs according to different requirements on the synchronization, the available jamming energy and the jamming power constraints. Extensive MATLAB experiments are conducted on the basis of the WLAN Toolbox, which demonstrate the proposed IJSs can effectively degrade the reception of the eavesdropper and outperform the widespread continuous jamming scheme (CJS) when the available jamming energy is limited.

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