Secure Beamforming for MIMO Two-Way Communications with an Untrusted Relay

This paper studies the secure beamforming design in a multiple-antenna three-node system where two source nodes exchange messages with the help of an untrusted relay node. The relay acts as both an essential signal forwarder and a potential eavesdropper. Both two-phase and three-phase two-way relay strategies are considered. Our goal is to jointly optimize the source and relay beamformers for maximizing the secrecy sum rate of the two-way communications. We first derive the optimal relay beamformer structures. Then, iterative algorithms are proposed to find source and relay beamformers jointly based on alternating optimization. Furthermore, we conduct asymptotic analysis on the maximum secrecy sum-rate. Our analysis shows that when all transmit powers approach infinity, the two-phase two-way relay scheme achieves the maximum secrecy sum rate if the source beamformers are designed such that the received signals at the relay align in the same direction. This reveals an important advantage of signal alignment technique in against eavesdropping. It is also shown that if the source powers approach zero the three-phase scheme performs the best while the two-phase scheme is even worse than direct transmission. Simulation results have verified the efficiency of the secure beamforming algorithms as well as the analytical findings.Comment: 10 figures, Submitted to IEEE Transactions on Signal Processin

Electron transfer theory revisit: Quantum solvation effect

The effect of solvation on the electron transfer (ET) rate processes is investigated on the basis of the exact theory constructed in J. Phys. Chem. B Vol. 110, (2006); quant-ph/0604071. The nature of solvation is studied in a close relation with the mechanism of ET processes. The resulting Kramers' turnover and Marcus' inversion characteristics are analyzed accordingly. The classical picture of solvation is found to be invalid when the solvent longitudinal relaxation time is short compared with the inverse temperature.Comment: 5 pages, 3 figures. J. Theo. & Comput. Chem., accepte

Analysis of the bioactive components from different growth stages of Fritillaria taipaiensis P. Y. Li

AbstractHigh-performance liquid chromatography (HPLC) coupled with an evaporative light scattering detector (ELSD) or a diode array detector (DAD) were utilized for the quantitative analysis of 4 alkaloids (peimisine, sipeimine, peimine and peiminine) and 9 nucleosides and nucleobases (uracil, uridine, adenosine, adenine, inosine, thymine, cytidine, guanosine and thymidine) from Fritillaria taipaiensis P. Y. Li that had been cultivated in the same field for 2–6 years. The content of peimisine, sipeimine, peimine, peiminine, uracil, thymine, adenine and inosine in plants cultivated for 2–4 years was significantly higher than that of plants cultivated for 5–6 years, while the content of cytidine, uridine, guanosine, thymidine and adenosine did not change over this period. This is the first evaluation of variation in the bioactive compounds in F. taipaiensis over its life cycle

Characterising the regulatory network of MYB26 during anther dehiscence

Pollen development and release involves a number of important stages, which govern the success of fertilisation and thus indirectly crop yields. The secondary cell wall in the anther plays a pivotal role in anther dehiscence by offering mechanical strength required for opening and pollen release (Wilson et al. 2011). MYB26/MALE STERILE35(MS35) is a key regulator of the secondary thickening development in anther, mutation of this gene results in a failure of anther dehiscence and functional male sterility (Steiner-Lange et al. 2003; Yang et al. 2007). However, the regulatory network of MYB26 remains to be fully identified. To address this issue, the MYB26 direct targets and interactive proteins were investigated. Putative targets of MYB26 were selected, based on their expression patterns, from previously determined expression profiles of the ms35 mutant (Song, 2009). PKSP, a receptor-like cytoplasmic kinase (RLCK) was co-expressed with MYB26. Chromatin immunoprecipitation (ChIP)-PCR indicated that MYB26 may bind to the first intron of PKSP. The NAC SECONDARY WALL–PROMOTING FACTOR1 (NST1) and NST2 genes have been demonstrated as direct targets of MYB26 in ChIP-PCR. However, electrophoretic mobility shift assay (EMSA) did not show binding and retardation, possibly due to the requirement of additional proteins to facilitate MYB26 binding. MYB26 interactive proteins were investigated using the yeast two-hybrid system (C.Yang, Z.A.Wilson, unpublished data) and Förster resonance energy transfer (FRET) assays. Y2H560, a CHY-type/RING-type Zinc finger protein and Y2H320/TGA9, a bZIP transcription factor family protein interacted with MYB26 in plant cell nuclei. Y2H320/TGA9 has been shown to be functionally redundant with TGA10 in regulating anther development (Murmu et al. 2010). The tga9tga10 double mutant produced indehiscent anthers and was male sterile due to the developmental arrest of the adaxial anther lobes and abnormal tapetum and pollen development in the abaxial anther lobes. In summary, MYB26 appears to regulate endothecium development and secondary thickening formation and thus anther dehiscence probably through directly regulating the subfamily VII RLCK PKSP and the NAC transcription factors NST1, NST2 and by interacting with a CHY-type/RING-type Zinc finger protein Y2H560 and the bZIP transcription factor Y2H320/TGA9

A Low-cost, High-impact Node Injection Approach for Attacking Social Network Alignment

Social network alignment (SNA) holds significant importance for various downstream applications, prompting numerous professionals to develop and share SNA tools. Unfortunately, these tools can be exploited by malicious actors to integrate sensitive user information, posing cybersecurity risks. While many researchers have explored attacking SNA (ASNA) through a network modification attack way, practical feasibility remains a challenge. This paper introduces a novel approach, the node injection attack. To overcome the problem of modeling and solving within a limited time and balancing costs and benefits, we propose a low-cost, high-impact node injection attack via dynamic programming (DPNIA) framework. DPNIA models ASNA as a problem of maximizing the number of confirmed incorrect correspondent node pairs who have a greater similarity scores than the pairs between existing nodes, making ASNA solvable. Meanwhile, it employs a cross-network evaluation method to identify node vulnerability, facilitating a progressive attack from easy to difficult. Additionally, it utilizes an optimal injection strategy searching method, based on dynamic programming, to determine which links should be added between injected nodes and existing nodes, thereby achieving a high impact for attack effectiveness at a low cost. Experiments on four real-world datasets consistently demonstrate that DPNIA consistently and significantly outperforms various attack baselines

Kinetics and thermodynamics of electron transfer in Debye solvents: An analytical and nonperturbative reduced density matrix theory

A nonperturbative electron transfer rate theory is developed based on the reduced density matrix dynamics, which can be evaluated readily for the Debye solvent model without further approximation. Not only does it recover for reaction rates the celebrated Marcus' inversion and Kramers' turnover behaviors, the present theory also predicts for reaction thermodynamics, such as equilibrium Gibbs free-energy and entropy, some interesting solvent-dependent features that are calling for experimental verification. Moreover, a continued fraction Green's function formalism is also constructed, which can be used together with Dyson equation technique, for efficient evaluation of nonperturbative reduced density matrix dynamics.Comment: 8 pages, 5 figures. J. Phys. Chem. B, accepte

Upper Gastrointestinal Endoscopy Detection of Synchronous Multiple Primary Cancers in Esophagus and Stomach: Single Center Experience from China

The present study was undertaken to clarify the prevalence and clinicopathological features of synchronous multiple primary cancers (SMPCs) under upper gastrointestinal endoscopic examination. We enrolled 45,032 consecutive patients who underwent upper gastrointestinal endoscopic examination for digestive disease from January 2006 to December 2007 in our hospital and analyzed the clinicopathological features of SMPCs in esophagus and stomach. SMPCs are defined as two or over two different cancerous lesions developing in the same or other organs within 6 months. SMPCs were identified in 46 patients (0.1%). The gender ratio was 5.6 : 1 (male/female) and the mean age was 59.4 years. Synchronous esophageal and gastric cancers were the most frequent, being seen in 32 patients (0.07%). The most common histological types of SMPCs were squamous cell carcinoma in esophagus and adenocarcinoma in stomach, respectively. There were 27 (59%) SMPCs patients who had the history of simultaneous exposure to tobacco smoking and alcohol drinking. Additionally, 32 (78%) esophageal squamous cell cancers were associated with tobacco use. And 23 adenocarcinomas of the stomach were associated with Helicobacter pylori infection