Biblio

We investigate an implementation of a compressive sampling (CS) stepped frequency ground penetrating radar. Due to the small number of targets, the B-scan is represented as a sparse image. Due to the nature of stepped frequency radar, smaller number of random frequencies can be used to obtain each A-scan (sparse delays). Also, the measurements obtained from different antenna positions can be reduced to a smaller number of random antenna positions. We also use the structure in the B-scan, i.e. the shape of the targets, which can be known, for instance, when detecting land mines. We demonstrate our method using radar data available from the Web from the land mine targets buried in the ground. We use group sparsity, i.e. we assume that the targets have some non-zero (and presumably known) dimension in the cross-range coordinate of the B-scan. For such targets, we also use the Markov chain model for the targets, where we simultaneously estimate the model parameters using the EMturboGAMP algorithm. Both approaches result in improved performance.

A detailed model of an attack on the power grid involves both a preparation stage as well as an execution stage of the attack. This paper introduces a novel Hybrid Attack Model (HAM) that combines Probabilistic Learning Attacker, Dynamic Defender (PLADD) model and a Markov Chain model to simulate the planning and execution stages of a bad data injection attack in power grid. We discuss the advantages and limitations of the prior work models and of our proposed Hybrid Attack Model and show that HAM is more effective compared to individual PLADD or Markov Chain models.

Quantifying vulnerability and security levels for smart grid diversified link of networks have been a challenging task for a long period of time. Security experts and network administrators used to act based on their proficiencies and practices to mitigate network attacks rather than objective metrics and models. This paper uses the Markov Chain Model [1] to evaluate quantitatively the vulnerabilities associated to the 802.11 Wi-Fi network in a smart grid. Administrator can now assess the level of severity of potential attacks based on determining the probability density of the successive states and thus, providing the corresponding security measures. This model is based on the observed vulnerabilities provided by the Common Vulnerabilities and Exposures (CVE) database explored by MITRE [2] to calculate the Markov processes (states) transitions probabilities and thus, deducing the vulnerability level of the entire attack paths in an attack graph. Cumulative probabilities referring to high vulnerability level in a specific attack path will lead the system administrator to apply appropriate security measures a priori to potential attacks occurrence.