Sparse Localization with a Mobile Beacon Based on LU Decomposition in Wireless Sensor Networks

Node localization is the core in wireless sensor network. It can be solved by powerful beacons, which are equipped with global positioning system devices to know their location information. In this article, we present a novel sparse localization approach with a mobile beacon based on LU decomposition. Our scheme firstly translates node localization problem into a 1-sparse vector recovery problem by establishing sparse localization model. Then, LU decomposition pre-processing is adopted to solve the problem that measurement matrix does not meet the re¬stricted isometry property. Later, the 1-sparse vector can be exactly recovered by compressive sensing. Finally, as the 1-sparse vector is approximate sparse, weighted Cen¬troid scheme is introduced to accurately locate the node. Simulation and analysis show that our scheme has better localization performance and lower requirement for the mobile beacon than MAP+GC, MAP-M, and MAP-M&N schemes. In addition, the obstacles and DOI have little effect on the novel scheme, and it has great localization performance under low SNR, thus, the scheme proposed is robust

Characterization of Highly Heterogeneous Heparin-Protein Complexes Using Novel Mass Spectrometry-Based Approaches

Heparin-like glycosaminoglycan (GAG) is a family of polysaccharide involved in variety of physiological processes. They have potentials to interact with a broad range of proteins and many of them hold crucial values in regulation of protein functions. My dissertation addresses the significance and challenges in the field of heparin-mediated studies, with a focus on the questions in biological and analytical aspects, which are largely hindered by the structural heterogeneity and function diversity of heparin. My dissertation reports the efforts I made in the past few years with respect to the development of novel analytical strategies based on a combination of mass spectrometry, ion-mobility, gas-phase chemistry and chromatography, with success in characterizing protein-GAG interacting stoichiometry and deciphering the structural code related to protein-GAG affinity

An Extended Network Coding Opportunity Discovery Scheme in Wireless Networks

Network coding is known as a promising approach to improve wireless network performance. How to discover the coding opportunity in relay nodes is really important for it. There are more coding chances, there are more times it can improve network throughput by network coding operation. In this paper, an extended network coding opportunity discovery scheme (ExCODE) is proposed, which is realized by appending the current node ID and all its 1-hop neighbors' IDs to the packet. ExCODE enables the next hop relay node to know which nodes else have already overheard the packet, so it can discover the potential coding opportunities as much as possible. ExCODE expands the region of discovering coding chance to n-hops, and have more opportunities to execute network coding operation in each relay node. At last, we implement ExCODE over the AODV protocol, and efficiency of the proposed mechanism is demonstrated with NS2 simulations, compared to the existing coding opportunity discovery scheme.Comment: 15 pages and 7 figure

Robust Transceiver Design for MISO Interference Channel with Energy Harvesting

In this paper, we consider multiuser multiple-input single-output (MISO) interference channel where the received signal is divided into two parts for information decoding and energy harvesting (EH), respectively. The transmit beamforming vectors and receive power splitting (PS) ratios are jointly designed in order to minimize the total transmission power subject to both signal-to-interference-plus-noise ratio (SINR) and EH constraints. Most joint beamforming and power splitting (JBPS) designs assume that perfect channel state information (CSI) is available; however CSI errors are inevitable in practice. To overcome this limitation, we study the robust JBPS design problem assuming a norm-bounded error (NBE) model for the CSI. Three different solution approaches are proposed for the robust JBPS problem, each one leading to a different computational algorithm. Firstly, an efficient semidefinite relaxation (SDR)-based approach is presented to solve the highly non-convex JBPS problem, where the latter can be formulated as a semidefinite programming (SDP) problem. A rank-one recovery method is provided to recover a robust feasible solution to the original problem. Secondly, based on second order cone programming (SOCP) relaxation, we propose a low complexity approach with the aid of a closed-form robust solution recovery method. Thirdly, a new iterative method is also provided which can achieve near-optimal performance when the SDR-based algorithm results in a higher-rank solution. We prove that this iterative algorithm monotonically converges to a Karush-Kuhn-Tucker (KKT) solution of the robust JBPS problem. Finally, simulation results are presented to validate the robustness and efficiency of the proposed algorithms.Comment: 13 pages, 8 figures. arXiv admin note: text overlap with arXiv:1407.0474 by other author

Joint Transceiver Design Algorithms for Multiuser MISO Relay Systems with Energy Harvesting

In this paper, we investigate a multiuser relay system with simultaneous wireless information and power transfer. Assuming that both base station (BS) and relay station (RS) are equipped with multiple antennas, this work studies the joint transceiver design problem for the BS beamforming vectors, the RS amplify-and-forward transformation matrix and the power splitting (PS) ratios at the single-antenna receivers. Firstly, an iterative algorithm based on alternating optimization (AO) and with guaranteed convergence is proposed to successively optimize the transceiver coefficients. Secondly, a novel design scheme based on switched relaying (SR) is proposed that can significantly reduce the computational complexity and overhead of the AO based designs while maintaining a similar performance. In the proposed SR scheme, the RS is equipped with a codebook of permutation matrices. For each permutation matrix, a latent transceiver is designed which consists of BS beamforming vectors, optimally scaled RS permutation matrix and receiver PS ratios. For the given CSI, the optimal transceiver with the lowest total power consumption is selected for transmission. We propose a concave-convex procedure based and subgradient-type iterative algorithms for the non-robust and robust latent transceiver designs. Simulation results are presented to validate the effectiveness of all the proposed algorithms

Robust MMSE Precoding Strategy for Multiuser MIMO Relay Systems with Switched Relaying and Side Information

In this work, we propose a minimum mean squared error (MMSE) robust base station (BS) precoding strategy based on switched relaying (SR) processing and limited transmission of side information for interference suppression in the downlink of multiuser multiple-input multiple-output (MIMO) relay systems. The BS and the MIMO relay station (RS) are both equipped with a codebook of interleaving matrices. For a given channel state information (CSI) the selection function at the BS chooses the optimum interleaving matrix from the codebook based on two optimization criteria to design the robust precoder. Prior to the payload transmission the BS sends the index corresponding to the selected interleaving matrix to the RS, where the best interleaving matrix is selected to build the optimum relay processing matrix. The entries of the codebook are randomly generated unitary matrices. Simulation results show that the performance of the proposed techniques is significantly better than prior art in the case of imperfect CSI.

An exploration of the potential approaches to lexis-focused College English teaching and learning in the 2007 curriculum: implications for teachers

According to the author’s long-term observation of College English teaching and learning in Harbin University of Commerce in China, vocabulary accumulation and rote learning made up the repertoire of College English pedagogy and this was also argued by Hird (1995) and many other Chinese ELT researchers (e.g. Yan & Wu, 2002). After 2007, the new syllabus and textbooks have been released and the Internet-based approach to self-directed learning has been put into practice in the on-line course. However, there still seems a distance to the fundamental change of College English teaching and learning. The biggest challenges might lie in the teachers’ understanding of these potential innovative approaches proposed in the new syllabus and textbooks and their cognition of the nature of language and learning, so the old questions turn up again: What do we teach? and How do we teach? On the basis of this background, this research puts focus on exploration of potential approaches to lexis-focused College English teaching and learning in the 2007 curriculum and some possible challenges confronting the teachers in aspects of their classroom practice. The issues to be investigated in this research are mainly involved with the essence of lexis or vocabulary in the College English curriculum and the potential approaches to innovating lexis-focused College English teaching and learning. In order to investigate these issues, two research methods are employed: namely literature review and documentary analysis. The former provides this research with a review of traditional College English pedagogy in China as well as the nature of language and learning from a lexical perspective. The latter tends to meet the answers of research questions via analysis of the syllabus-College English Curriculum Requirements 2007 and the textbook-New Horizon College English. Throughout the documentary investigation in this research, it is found out that lexis as the basis of language system and lexis teaching and learning as the core of language pedagogy have been stereotyped to underpin the College English curriculum development. Being required in the syllabus document, learner autonomy as a catchall term underpinned with scaffolding and interaction, is emphasized in the new textbook with assistance of an on-line course. In term of textbook analysis, it is also found out that most of the requirements set in the College English syllabus are applied into tasks and activities, in which skill-based learning, lexis-focused learning and autonomous learning are potentially put into focus. As for the conclusion, based on the potential challenges in front of College English teaching and learning and the findings from the documentary analysis in this research, some implications for the CE teachers are put forward. They are mainly concerned with lexis being the basis of language, the teacher being the learning-instructor and learner autonomy being the final goal of College English pedagogy