@article{li_dai_zhang_2010, title={Location-Aided Fast Distributed Consensus in Wireless Networks}, volume={56}, ISSN={["1557-9654"]}, DOI={10.1109/tit.2010.2081030}, abstractNote={Existing works on distributed consensus explore linear iterations based on reversible Markov chains, which contribute to the slow convergence of the algorithms. It has been observed that by overcoming the diffusive behavior of reversible chains, certain nonreversible chains lifted from reversible ones mix substantially faster than the original chains. In this paper, the idea of Markov chain lifting is studied to accelerate the convergence of distributed consensus, and two general pseudoalgorithms are presented. These pseudoalgorithms are then instantiated through a class of location-aided distributed averaging (LADA) algorithms for wireless networks, where nodes' coarse location information is used to construct nonreversible chains that facilitate distributed computing and cooperative processing. Our first LADA algorithm is designed for grid networks; for a k × k grid network, it achieves an ε-averaging time of O(k log(ε-1)). Based on this algorithm, in a wireless network with transmission range r, an ε-averaging time of O(r-1 log(ε-1)) can be attained through a centralized algorithm. Subsequently, a distributed LADA algorithm is presented, achieving the same scaling law in averaging time as the centralized scheme in wireless networks for all r satisfying the connectivity requirement; the constructed chain also attains the optimal scaling law in terms of an important mixing metric, the fill time, in its class. Finally, a cluster-based LADA algorithm is proposed, which, requiring no central coordination, provides the additional benefit of reduced message complexity compared with the distributed LADA algorithm.}, number={12}, journal={IEEE TRANSACTIONS ON INFORMATION THEORY}, author={Li, Wenjun and Dai, Huaiyu and Zhang, Yanbing}, year={2010}, month={Dec}, pages={6208–6227} }
 @article{zhang_dai_2009, title={A Real Orthogonal Space-Time Coded UWB Scheme for Wireless Secure Communications}, ISSN={["1687-1499"]}, DOI={10.1155/2009/571903}, abstractNote={Recent research reveals that information security and information-hiding capabilities can be enhanced by proper exploitation of space-time techniques. Meanwhile, intrinsic properties of ultra-wideband (UWB) signals make it an outstanding candidate for secure applications. In this paper, we propose a space-time coding scheme for impulse radio UWB systems. A novel real orthogonal group code is designed for multi-antenna UWB signals to exploit the full spatial diversity gain and achieve the perfect communication secrecy. Its performance in a frequency-selective fading channel is analyzed. The transmission secrecy, including low probability of detection (LPD), low probability of intercept (LPI), and anti-jamming performance, is investigated, and some fundamental tradeoffs between these secrecy metrics are also addressed. A comparison of the proposed scheme with the direct sequence spread spectrum (DSSS) technique is carried out, which demonstrates that proper combination of UWB and space-time coding can provide substantial enhancement to wireless secure communications over other concurrent systems.}, journal={EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING}, author={Zhang, Yanbing and Dai, Huaiyu}, year={2009} }
 @article{oshima_koike_zhang_kondo_moteki_takegawa_miyazaki_2009, title={Aging of black carbon in outflow from anthropogenic sources using a mixing state resolved model: Model development and evaluation}, volume={114}, ISBN={0148-0227}, journal={Journal of Geophysical Research. Atmospheres (Online)}, author={Oshima, N. and Koike, M. and Zhang, Y. and Kondo, Y. and Moteki, N. and Takegawa, N. and Miyazaki, Y.}, year={2009} }
 @inproceedings{zhang_dai_2009, title={Structured variational methods for distributed inference in wireless ad hoc and sensor networks}, DOI={10.1109/icassp.2009.4960198}, abstractNote={In this paper, a variational message passing framework is proposed for Markov random fields, which is computationally more efficient and admits wider applicability compared to the belief propagation algorithm. Based on this framework, structured variational methods are explored to take advantage of both the simplicity of variational approximation (for inter-cluster processing) and the accuracy of exact inference (for intra-cluster processing). Its performance is elaborated on a Gaussian Markov random field, through both theoretical analysis and simulation results.}, booktitle={International conference on acoustics speech and signal processing}, author={Zhang, Y. B. and Dai, H. Y.}, year={2009}, pages={2773–2776} }
 @article{zhang_dai_2007, title={Energy-efficiency and transmission strategy selection in cooperative wireless sensor networks}, volume={9}, ISSN={["1976-5541"]}, DOI={10.1109/JCN.2007.6182883}, abstractNote={Energy efficiency is one of the most critical concerns for wireless sensor networks. By allowing sensor nodes in close proximity to cooperate in transmission to form a virtual multiple-input multiple-output (MIMO) system, recent progress in wireless MIMO communications can be exploited to boost the system throughput, or equivalently reduce the energy consumption for the same throughput and BER target. However, these cooperative transmission strategies may incur additional energy cost and system overhead. In this paper, assuming that data collectors are equipped with antenna arrays and superior processing capability, energy efficiency of relevant traditional and cooperative transmission strategies: Single-input-multiple-output (SIMO), space-time block coding (STBC), and spatial multiplexing (SM) are studied. Analysis in the wideband regime reveals that, while receive diversity introduces significant improvement in both energy efficiency and spectral efficiency, further improvement due to the transmit diversity of STBC is limited, as opposed to the superiority of the SM scheme especially for non-trivial spectral efficiency. These observations are further confirmed in our analysis of more realistic systems with limited bandwidth, finite constellation sizes, and a target error rate. Based on this analysis, general guidelines are presented for optimal transmission strategy selection in system level and link level, aiming at minimum energy consumption while meeting different requirements. The proposed selection rules, especially those based on system-level metrics, are easy to implement for sensor applications. The framework provided here may also be readily extended to other scenarios or applications.}, number={4}, journal={JOURNAL OF COMMUNICATIONS AND NETWORKS}, author={Zhang, Yanbing and Dai, Huaiyu}, year={2007}, month={Dec}, pages={473–481} }