In this paper, we investigate the physical layer security of a full-duplex base station (BS) aided system in the worst case, where an uplink transmitter (UT) and a downlink receiver (DR) are both equipped with a single antenna, while a powerful eavesdropper is equipped with multiple antennas. For securing the confidentiality of signals transmitted from the BS and UT, an artificial noise (AN) aided secrecy beamforming scheme is proposed, which is robust to the realistic imperfect state information of both the eavesdropping channel and the residual self-interference channel. Our objective function is that of maximizing the worst-case sum secrecy rate achieved by the BS and UT, through jointly optimizing the beamforming vector of the confidential signals and the transmit covariance matrix of the AN. However, the resultant optimization problem is non-convex and non-linear. In order to efficiently obtain the solution, we transform the non-convex problem into a sequence of convex problems by adopting the block coordinate descent algorithm. We invoke a linear matrix inequality for finding its Karush-Kuhn-Tucker (KKT) solution. In order to evaluate the achievable performance, the worst-case secrecy rate is derived analytically. Furthermore, we construct another secrecy transmission scheme using the projection matrix theory for performance comparison. Our simulation results show that the proposed robust secrecy transmission scheme achieves substantial secrecy performance gains, which verifies the efficiency of the proposed method.

In this article, diblock copolymer (DBC), poly (methyl methacrylate)-block-poly (acrylic acid) was synthesized by reversible addition-fragmentation chain transfer polymerization (RAFT). The DBC-Eu ³ D. Liu, Z. Wang, H. Yu, and J. You, Fluorescence properties of novel rare earth complexes using carboxyl-containing polyaryletherketones as macromolecular ligands. Eur. Polym. J. 45, 2260–2268 (2009). [Crossref], [Web of Science ®] [Google Scholar] ⁺ solid micelles were prepared through the complex interaction between DBC and Eu ³ D. Liu, Z. Wang, H. Yu, and J. You, Fluorescence properties of novel rare earth complexes using carboxyl-containing polyaryletherketones as macromolecular ligands. Eur. Polym. J. 45, 2260–2268 (2009). [Crossref], [Web of Science ®] [Google Scholar] ⁺ ions. As cross-linker, Eu ³ D. Liu, Z. Wang, H. Yu, and J. You, Fluorescence properties of novel rare earth complexes using carboxyl-containing polyaryletherketones as macromolecular ligands. Eur. Polym. J. 45, 2260–2268 (2009). [Crossref], [Web of Science ®] [Google Scholar] ⁺ ions accept the electron donation of the ligand groups (carboxyl) sited on the polar PAA segments of DBC and form the DBC-Eu ³ D. Liu, Z. Wang, H. Yu, and J. You, Fluorescence properties of novel rare earth complexes using carboxyl-containing polyaryletherketones as macromolecular ligands. Eur. Polym. J. 45, 2260–2268 (2009). [Crossref], [Web of Science ®] [Google Scholar] ⁺ solid micelles. The observations by transmission electron microscopy showed the embedment of Eu ³ D. Liu, Z. Wang, H. Yu, and J. You, Fluorescence properties of novel rare earth complexes using carboxyl-containing polyaryletherketones as macromolecular ligands. Eur. Polym. J. 45, 2260–2268 (2009). [Crossref], [Web of Science ®] [Google Scholar] ⁺ ions in DBC and the nonpolar segments [poly (methyl methacrylate)] of DBC play a role of compatible agent for DBC-Eu ³ D. Liu, Z. Wang, H. Yu, and J. You, Fluorescence properties of novel rare earth complexes using carboxyl-containing polyaryletherketones as macromolecular ligands. Eur. Polym. J. 45, 2260–2268 (2009). [Crossref], [Web of Science ®] [Google Scholar] ⁺ solid micelles to disperse in hydrophobic solvent [for example, dimethyl formamide] or polymer matrix. Very importantly, we found the dependence of the morphological structure (i.e. the size of solid micelles) on the molecular weight of DBC. On the other hand, the dependence of photoluminescent property of DBC-Eu ³ D. Liu, Z. Wang, H. Yu, and J. You, Fluorescence properties of novel rare earth complexes using carboxyl-containing polyaryletherketones as macromolecular ligands. Eur. Polym. J. 45, 2260–2268 (2009). [Crossref], [Web of Science ®] [Google Scholar] ⁺ solid micelles on the molecular weight of DBC and the ratio of polar and nonpolar segments was confirmed through our experiments. The results showed the existence of enhanced photoluminescent property of DBC-Eu ³ D. Liu, Z. Wang, H. Yu, and J. You, Fluorescence properties of novel rare earth complexes using carboxyl-containing polyaryletherketones as macromolecular ligands. Eur. Polym. J. 45, 2260–2268 (2009). [Crossref], [Web of Science ®] [Google Scholar] ⁺ solid micelles.

In this article, we first investigate secure communications for a two-hop interference channel relay system with imperfect channel estimation in the wireless Internet of Things (IoT), where K source-destination pairs communicate simultaneously when an eavesdropper exists. We jointly conceive source, relay and destination matrices upon minimizing total mean-squared error (MSE) of all legitimate destinations while keeping the MSE at eavesdropper above a given threshold. We illuminate that the design of the source, relay and destination matrices is subject to both transmit power constraints and secrecy requirements. More specifically, we propose an efficient robust iterative distributed algorithm to simplify the process of the joint design for optimal source, relay and destination matrices. Furthermore, the convergence of the iterative distributed algorithm is described. Additionally, the performances of our proposed algorithm, such as its secrecy rate and MSE, are characterized in the form of simulation results. The simulation results reveal that the proposed algorithm is superior to the traditional approach. As a benefit, secure communications can be ensured by using the proposed algorithm for the multiple input multiple output (MIMO) interference relay IoT network in the presence of an eavesdropper.

In this paper, we investigate the physical layer security of a full-duplex base station (BS) aided system in the worst case, where an uplink transmitter (UT) and a downlink receiver (DR) are both equipped with a single antenna, while a powerful eavesdropper is equipped with multiple antennas. For securing the confidentiality of signals transmitted from the BS and UT, an artificial noise (AN) aided secrecy beamforming scheme is proposed, which is robust to the realistic imperfect state information of both the eavesdropping channel and the residual self-interference channel. Our objective function is that of maximizing the worst-case sum secrecy rate achieved by the BS and UT, through jointly optimizing the beamforming vector of the confidential signals and the transmit covariance matrix of the AN. However, the resultant optimization problem is non-convex and non-linear. In order to efficiently obtain the solution, we transform the non-convex problem into a sequence of convex problems by adopting the block coordinate descent algorithm. We invoke a linear matrix inequality for finding its Karush-Kuhn-Tucker (KKT) solution. In order to evaluate the achievable performance, the worst-case secrecy rate is derived analytically. Furthermore, we construct another secrecy transmission scheme using the projection matrix theory for performance comparison. Our simulation results show that the proposed robust secrecy transmission scheme achieves substantial secrecy performance gains, which verifies the efficiency of the proposed method.

This paper examines the research on intelligent fault diagnosis and prediction in the operation of microgrids under the context of information-physical fusion. Initially, the paper introduces the network attack issues faced by microgrids, encompassing various types of attacks and basic attack models. Subsequently, the impact of information-physical fusion on fault prediction in microgrids is explored, with particular emphasis on fault prediction techniques targeting malicious network attacks. Moreover, the paper studies fault diagnosis and recovery in microgrids under the framework of information-physical fusion, including fault diagnosis during deception attacks and fault recovery based on resilient control. The paper concludes with a summary of research progress and application examples, as well as highlighting current challenges and future research directions in the field of fault diagnosis and prediction in micro-grids under information-physical fusion. The study demonstrates that through the application of information-physical fusion approaches, the fault prediction capability of microgrids can be enhanced, providing solutions for fault diagnosis and recovery in the face of malicious attacks. Nevertheless, there are still research challenges that need to be addressed, and future studies will continue to explore these issues and find more advanced and reliable technologies to enhance the security and reliability of microgrids.