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Inhibition of Microcystis aeruginosa by the Extracellular Substances from an Aeromonas sp
( Yu Mei Liu ),( Ming Jun Chen ),( Meng Hui Wang1 ),( Rui Bao Jia ),( Li Li ) 한국미생물 · 생명공학회 2013 Journal of microbiology and biotechnology Vol.23 No.9
Growth of Microcystis aeruginosa could be inhibited significantly within 24 h by the extracellular substances prepared from Aeromonas sp. strain FM. During the treatment, the concentration of extracellular soluble carbohydrates increased significantly in algal culture. Morphological and ultrastructural changes in M. aeruginosa cells, including breakage of the cell surface, secretion of mucilage, and intracellular disorganization of thylakoids, were observed. HPLC-MS analysis showed that the extracellular substances of Aeromonas sp. strain FM were a mixture of free amino acids, tripeptides, and clavulanate. Among these, the algaelysis effects of lysine and clavulanate were confirmed.
Function of Global Regulator CodY in Bacillus thuringiensis BMB171 by Comparative Proteomic Analysis
( Ming Xia Qi ),( Fei Mei ),( Hui Wang ),( Ming Sun ),( Ge Jiao Wang ),( Ziniu Yu ),( Yeon Ho Je ),( Ming Shun Li ) 한국미생물 · 생명공학회 2015 Journal of microbiology and biotechnology Vol.25 No.2
CodY is a highly conserved protein in low G+C gram-positive bacteria that regulates genes involved in sporulation and stationary-phase adaptation. Bacillus thuringiensis is a grampositive bacterium that forms spores and parasporal crystals during the stationary phase. To our knowledge, the regulatory mechanism of CodY in B. thuringiensis is unknown. To study the function of CodY protein in B. thuringiensis, BMB171codY- was constructed in a BMB171 strain. A shuttle vector containing the ORF of cry1Ac10 was transformed into BMB171 and BMB171codY-, named BMB171cry1Ac and BMB171codY-cry1Ac, respectively. Some morphological and physiological changes of codY mutant BMB171codY-cry1Ac were observed. A comparative proteomic analysis was conducted for both BMB171codY-cry1Ac and BMB171cry1Ac through two-dimensional gel electrophoresis and MALDI-TOF-MS/MS analysis. The results showed that the proteins regulated by CodY are involved in microbial metabolism, including branched-chain amino acid metabolism, carbohydrate metabolism, fatty acid metabolism, and energy metabolism. Furthermore, we found CodY to be involved in sporulation, biosynthesis of poly-β-hydroxybutyrate, growth, genetic competence, and translation. According to the analysis of differentially expressed proteins, and physiological characterization of the codY mutant, we performed bacterial one-hybrid and electrophoretic mobility shift assay experiments and confirmed the direct regulation of genes by CodY, specifically those involved in metabolism of branched-chain amino acids, ribosomal recycling factor FRR, and the late competence protein ComER. Our data establish the foundation for in-depth study of the regulation of CodY in B. thuringiensis, and also offer a potential biocatalyst for functions of CodY in other bacteria.
Ming-Hui Wang,Kenko Uchida 제어로봇시스템학회 2012 제어로봇시스템학회 국제학술대회 논문집 Vol.2012 No.10
This paper investigates the consensus problem of the second-order multi-agent systems with communication channel constraint on signal amplitude. Communication delays as one kind of channel constraints in the second-order multi-agent systems have been discussed in the recent literature while in this paper consensus problem of second-order multi-agent systems with communication channel constraint on signal amplitude is investigated. A state-dependent switching parameter is introduced into the consensus protocol. A sufficient condition is obtained for the consensus problem of the second-order multi-agent systems with communication channel constraint based on our early work. A simple example is also given to verify the effectiveness of the proposed theorem.
A Linear Analog Network Coding for Asynchronous Two-Way Relay Networks
Hui-Ming Wang,Xiang-Gen Xia,Qinye Yin IEEE 2010 IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS Vol.9 No.12
<P>Time asynchronism is a practical issue need to be addressed for a general distributed two-way relay network, where two terminal nodes exchange information through multiple spatial-separated relay nodes. In this letter, we propose an analog network coding (ANC) scheme for a time asynchronous two-way relay network. In the proposed scheme, each relay node linearly transforms the received mixed asynchronous signals in the first time-slot by a Toeplitz matrix, and then broadcasts them back to the terminals in the second time-slot. A sufficient condition is derived for the proposed ANC to achieve full cooperative diversity using only linear receivers at the terminal nodes, such as zero-forcing (ZF), or minimum mean square error (MMSE) receivers, with any delay profiles of the timing errors. The decoding of the proposed ANC scheme is computationally efficient and the symbol rate can approach 1, when the coding block length is sufficiently large compared to the number of relay nodes R and the timing errors.</P>
Artificial Noise Assisted Secure Transmission for Distributed Antenna Systems
Wang, Hui-Ming,Wang, Chao,Ng, Derrick Wing Kwan,Lee, Moon Ho,Xiao, Jia Institute of Electrical and Electronics Engineers 2016 IEEE transactions on signal processing Vol.64 No.15
<P>This paper studies the artificial noise (AN) assisted secure transmission for a distributed antenna systems (DAS). To avoid a significant overhead caused by full legitimate channel state information (CSI) acquisition, tracking and collection in the central processor, we propose a distributed AN scheme utilizing the large-scale CSI of the legitimate receiver and eavesdropper. Our objective is to maximize the ergodic secrecy rate (ESR) via optimizing the power allocation between the confidential signal and AN for each remote antenna (RA) under the per-antenna power constraint. Specifically, exploiting random matrix theory, we first establish an analytical expression of the achievable ESR, which leads to a non-convex optimization problem with multiple non-convex constraints in the form of high-order fixed-point equations. To handle the intractable constraints, we recast it into a max-min optimization problem, and propose an iterative block coordinate descent (BCD) algorithm to provide a stationary solution. The BCD algorithm is composed of three subproblems, where the first two subproblems are convex with closed-form solutions, and the last one is a convex-concave game whose saddle-point is located by a tailored barrier algorithm. Simulation results validate the effectiveness of the proposed iterative algorithm and show that our scheme not only reduces the system overhead greatly but also maintains a good secrecy performance.</P>
Wang, Xian-Yu,Wang, Songhu,Hinse, Tobias C.,Li, Kai,Wang, Yong-Hao,Laughlin, Gregory,Liu, Hui-Gen,Zhang, Hui,Wu, Zhen-Yu,Zhou, Xu,Zhou, Ji-Lin,Hu, Shao-Ming,Wu, Dong-Hong,Peng, Xi-Yan,Chen, Yuan-Yuan Astronomical Society of the Pacific 2018 Publications of the Astronomical Society of the Pa Vol.130 No.988
Distributed Beamforming for Physical-Layer Security of Two-Way Relay Networks
Hui-Ming Wang,Qinye Yin,Xiang-Gen Xia IEEE 2012 IEEE transactions on signal processing Vol.60 No.7
<P>In this paper, we address the security of a two-way relay network in the presence of an eavesdropper, where each node is only equipped with single antenna. We propose two-phase distributed analog network coding, or distributed beamforming and power allocation to enhance the secrecy sum rate of the data exchange. In the first phase, the two terminals broadcast their information data simultaneously to all the relay nodes. In the second phase, three different security schemes are proposed: optimal beamforming, null-space beamforming, and artificial noise beamforming. In the first scheme, the objective is to achieve the maximum secrecy sum rate of the two terminals. Mathematically, the objective function is difficult to optimize. In the second scheme, we maximize the total information exchanged while we eliminate the information leakage completely, subject to the total transmission power constraint. We show that the problem has a unique and global optimum, which can be solved using bisection method. When the instantaneous channel state information of the eavesdropper is not available, we propose an artificial noise beamforming in the third scheme. We minimize the information transmission power so that the artificial noise power is maximized to eliminate information leakage, under the constraints of quality of service (QoS) required by terminals. It is a second-order convex cone programming (SOCP) problem, thus can be efficiently solved using interior point methods. Numerical results are provided and analyzed to show the properties and efficiency of the proposed designs.</P>
Cluster Consensus of Multi-agent Systems with Communication Delay (ICCAS 2013)
Ming-Hui Wang,Kenko Uchida 제어로봇시스템학회 2013 제어로봇시스템학회 국제학술대회 논문집 Vol.2013 No.10
Cluster consensus problem of the multi-agent systems with communication delay is studied in this paper. We consider the multi-agent systems with a special Laplacian matrix as its system matrix. For two types of protocols with time-delay, our work shows that the multi-agent systems with communication delays can reach cluster consensus. Some numerical simulations are given to verify the effectiveness of the theoretical results.
Physical Layer Security in Heterogeneous Cellular Networks
Hui-Ming Wang,Tong-Xing Zheng,Jinhong Yuan,Towsley, Don,Moon Ho Lee IEEE 2016 IEEE TRANSACTIONS ON COMMUNICATIONS Vol.64 No.3
<P>The heterogeneous cellular network (HCN) is a promising approach to the deployment of 5G cellular networks. This paper comprehensively studies physical layer security in a multitier HCN where base stations (BSs), authorized users, and eavesdroppers are all randomly located. We first propose an access threshold-based secrecy mobile association policy that associates each user with the BS providing the maximum truncated average received signal power beyond a threshold. Under the proposed policy, we investigate the connection probability and secrecy probability of a randomly located user and provide tractable expressions for the two metrics. Asymptotic analysis reveals that setting a larger access threshold increases the connection probability while decreases the secrecy probability. We further evaluate the network-wide secrecy throughput and the minimum secrecy throughput per user with both connection and secrecy probability constraints. We show that introducing a properly chosen access threshold significantly enhances the secrecy throughput performance of a HCN.</P>