Multi-Antenna Transmission in Downlink Heterogeneous Cellular Networks Under A Threshold-Based Mobile Association Policy

Zheng, Tong-Xing,Wang, Hui-Ming,Lee, Moon Ho Institute of Electrical and Electronics Engineers 2017 IEEE Transactions on Communications Vol. No.

<P>With the recent emergence of 5G era, heterogeneous cellular networks (HCNs) have invoked a popular research interest. In this paper, we provide a comprehensive analysis for multi-antenna transmissions in a multi-tier downlink HCN. We first propose a reliability-oriented threshold-based mobile association policy, where each user connects to the strongest base station from which this user can obtain the largest <I>truncated long-term received power</I>. Under our mobile association policy, we derive analytical expressions for the exact outage probability of an arbitrary randomly located user, along with computationally convenient lower and upper bounds. Asymptotic analysis on the outage probability shows that introducing a large access threshold into mobile association significantly decreases the outage probability. We further investigate the spectrum efficiency and the energy efficiency of the HCN. Our theoretic analysis and numerical validations show that both the spectrum and energy efficiencies can be improved by properly choosing the access threshold.</P>

Response of ENSO amplitude to global warming in CESM large ensemble: uncertainty due to internal variability

Zheng, Xiao-Tong,Hui, Chang,Yeh, Sang-Wook Springer-Verlag 2018 Climate dynamics Vol.50 No.11

Physical Layer Security in Wireless Ad Hoc Networks Under A Hybrid Full-/Half-Duplex Receiver Deployment Strategy

Tong-Xing Zheng,Hui-Ming Wang,Jinhong Yuan,Zhu Han,Moon Ho Lee INSTITUTE OF ELECTRICAL AND ELECTRONICS ENGINEERS 2017 IEEE Transactions on Wireless Communications Vol. No.

<P>This paper studies physical layer security in a wireless ad hoc network with numerous legitimate transmitter-receiver pairs and eavesdroppers. A hybrid full-duplex (FD)/half-duplex receiver deployment strategy is proposed to secure legitimate transmissions, by letting a fraction of legitimate receivers work in the FD mode sending jamming signals to confuse eavesdroppers upon their information receptions, and letting the other receivers work in the half-duplex mode just receiving their desired signals. The objective of this paper is to choose properly the fraction of FD receivers for achieving the optimal network security performance. Both accurate expressions and tractable approximations for the connection outage probability and the secrecy outage probability of an arbitrary legitimate link are derived, based on which the area secure link number, network-wide secrecy throughput, and network-wide secrecy energy efficiency are optimized, respectively. Various insights into the optimal fraction are further developed, and its closed-form expressions are also derived under perfect self-interference cancellation or in a dense network. It is concluded that the fraction of FD receivers triggers a non-trivial tradeoff between reliability and secrecy, and the proposed strategy can significantly enhance the network security performance.</P>

Safeguarding Decentralized Wireless Networks Using Full-Duplex Jamming Receivers

Zheng, Tong-Xing,Wang, Hui-Ming,Yang, Qian,Lee, Moon Ho IEEE 2017 IEEE Transactions on Wireless Communications Vol.16 No.1

<P>In this paper, we study the benefits of full-duplex (FD) receiver jamming in enhancing the physical-layer security of a two-tier decentralized wireless network with each tier deployed with a large number of pairs of a single-antenna transmitter and a multi-antenna receiver. In the underlying tier, the transmitter sends unclassified information and the receiver works in the half-duplex (HD) mode receiving the desired signal. In the overlaid tier, the transmitter delivers confidential information in the presence of randomly located eavesdroppers, and the receiver works in the FD mode radiating jamming signals to confuse eavesdroppers and receiving the desired signal simultaneously. We provide a comprehensive performance analysis and network design under a stochastic geometry framework. Specifically, we consider the scenarios where each FD receiver uses single-and multi-antenna jamming, and analyze the connection probability and the secrecy outage probability of a typical FD receiver by deriving accurate expressions and more tractable approximations for the two probabilities. We also determine the optimal deployment density of the FD-mode tier to maximize the network-wide secrecy throughput subject to constraints including the given dual probabilities and the network-wide throughput of the HD-mode tier. Numerical results are demonstrated to verify our theoretical findings, and show that the network-wide secrecy throughput is significantly improved by properly deploying the FD-mode tier.</P>

Multi-Antenna Transmission With Artificial Noise Against Randomly Distributed Eavesdroppers

Tong-Xing Zheng,Hui-Ming Wang,Jinhong Yuan,Towsley, Don,Moon Ho Lee Institute of Electrical and Electronics Engineers 2015 IEEE Transactions on Communications Vol. No.

<P>In this paper, we study the secure multi-antenna transmission with artificial noise (AN) under slow fading channels coexisting with randomly located eavesdroppers. We provide a comprehensive secrecy performance analysis and system design/optimization under a stochastic geometry framework. Specifically, we first evaluate the secrecy outage performance, and derive a closed-form expression for the optimal power allocation ratio of the information signal power to the total transmit power that minimizes the secrecy outage probability (SOP). Subject to a SOP constraint, we then propose a dynamic parameter transmission scheme (DPTS) and a static parameter transmission scheme (SPTS) to maximize secrecy throughput, and provide explicit solutions on the optimal transmission parameters, including the wiretap code rates, the on-off transmission threshold and the power allocation ratio. Our results give new insight into secure transmission designs. For example, secrecy rate is a concave function of the power allocation ratio in DPTS, and AN plays a significant role under SOP constraints and in dense eavesdropper scenarios. In SPTS, transmission probability is a concave function of the power allocation ratio, and secrecy throughput is a quasi-concave function of the secrecy rate. Numerical results are demonstrated to validate our theoretical analysis.</P>

다차원적 브랜드 글로벌화가 스포츠웨어 브랜드의 품질;명성;태도;구매의도에 미치는 영향 : 중국 소비자를 중심으로

동정호(Zheng-Hao Tong),황진숙(Jin-Sook Hwang) 한국무역연구원 2021 무역연구 Vol.17 No.1

Purpose This study examined the effects of the multiple dimensions of perceived brand globalness on brand quality;prestige;attitude;and purchase intention of Chinese consumers. Moreover;the study investigated the moderating effects of consumer ethnocentrism. Design/Methodology/Approach The study included 470 male and female respondents who purchased sportswear products in China. The data analyses software used for the study were SPSS 22.0 for exploratory factor analysis;and AMOS 25.0 for confirmatory factor analysis and path analysis. Findings Results showed that perceived brand globalness is divided into three factors such as perceived market reach;perceived standardization;and global consumer culture positioning. Path analysis results revealed that all factors relative to perceived brand globalness are positively related to prestige. There were positive effects of quality and prestige on attitude and purchase intention. In addition;there were moderating effects of consumer ethnocentrism on the relationships among the variables. Research Implications Based on the results of the study;the marketing strategies for global brands targeting Chinese consumers can be effectively crafted and implemented.

Arabidopsis thaliana Metallothionein, AtMT2a, Mediates ROS Balance during Oxidative Stress

Wei Zhu,Dong-Xiao Zhao,Qing Miao,Tong-Tong Xue,Xin-Zheng Li,Cheng-Chao Zheng 한국식물학회 2009 Journal of Plant Biology Vol.52 No.6

Cold stress has been shown to induce the production of reactive oxygen species (ROS), which can elicit a potentially damaging oxidative burden on cellular metabolism. Here, the expression of a metallothionein gene (AtMT2a) was upregulated under low temperature and hydrogen peroxide (H2O2) stresses. The Arabidopsis T-DNA insertion mutant, mt2a, exhibited more sensitivity to cold stress compared to WT plants during the seed germination, and H2O2 levels in mt2a mutant were higher than that in WT plants during the cold stress. Synthetic GFP fused to AtMT2a was observed to be localized in cytosol. These results indicated that AtMT2a functions in tolerance against cold stress by mediating the ROS balance in the cytosol. Interestingly, mRNA level of AtMT2a was increased in seedlings of Arabidopsis cat2 mutant after cold treatment compared to WT seedlings, and overexpression of AtMT2a in cat2 could improve CAT activity under chilling stress. Moreover, the enzymatic activity of CAT in mt2a was higher than that in WT plants after cold treatment, suggesting that AtMT2a and CAT might complement each other in antioxidative process potentially in Arabidopsis. Taken together, our results provided a novel insight into the relationship between MTs and antioxidative enzymes in the ROS-scavenging system in plants.

User Identification Using Real Environmental Human Computer Interaction Behavior

( Tong Wu ),( Kangfeng Zheng ),( Chunhua Wu ),( Xiujuan Wang ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.6

In this paper, a new user identification method is presented using real environmental human-computer-interaction (HCI) behavior data to improve method usability. User behavior data in this paper are collected continuously without setting experimental scenes such as text length, action number, etc. To illustrate the characteristics of real environmental HCI data, probability density distribution and performance of keyboard and mouse data are analyzed through the random sampling method and Support Vector Machine(SVM) algorithm. Based on the analysis of HCI behavior data in a real environment, the Multiple Kernel Learning (MKL) method is first used for user HCI behavior identification due to the heterogeneity of keyboard and mouse data. All possible kernel methods are compared to determine the MKL algorithm’s parameters to ensure the robustness of the algorithm. Data analysis results show that keyboard data have a narrower range of probability density distribution than mouse data. Keyboard data have better performance with a 1-min time window, while that of mouse data is achieved with a 10-min time window. Finally, experiments using the MKL algorithm with three global polynomial kernels and ten local Gaussian kernels achieve a user identification accuracy of 83.03% in a real environmental HCI dataset, which demonstrates that the proposed method achieves an encouraging performance.

J Wave Syndromes: History and Current Controversies

Tong Liu,Gan-Xin YAn,Jifeng Zheng 대한심장학회 2016 Korean Circulation Journal Vol.46 No.5

The concept of J wave syndromes was first proposed in 2004 by Yan et al for a spectrum of electrocardiographic (ECG) manifestations of prominent J waves that are associated with a potential to predispose affected individuals to ventricular fibrillation (VF). Although the concept of J wave syndromes is widely used and accepted, there has been tremendous debate over the definition of J wave, its ionic and cellular basis and arrhythmogenic mechanism. In this review article, we attempted to discuss the history from which the concept of J wave syndromes (JWS) is evolved and current controversies in JWS.

The Effect of Salt and pH on the Phase Transition Behaviors of pH and Temperature-Responsive Poly(N,N-diethylacrylamide-co-methylacrylic acid)

Tong Huan Liu,Jian Fang,Ya Ping Zhang,Zheng Zhi Zeng 한국고분자학회 2008 Macromolecular Research Vol.16 No.8