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Low-complexity distributed differential spacetime coding scheme for amplify-and-forward cooperative networks

Science in china(Series F) 2009年第8期52卷 1418-1427页

作者： YU XiangBin1,2, BI GuangGuo3 & XU WeiYe4 1 College of Information Science and technology, nanjing University of Aeronautics and Astronautics, nanjing 210016, china 2 department of Electronic engineering, City University of Hong Kong, Hong Kong, china 3 National Mobile communications Research Laboratory, Southeast University, nanjing 210096, china 4 department of communication engineering, nanjing institute of technology, nanjing 211167, china College of Information Science and technology Nanjing University of Aeronautics and Astronautics Nanjing 210016 China department of Electronic engineering City University of Hong Kong Hong Kong China National Mobile communications Research Laboratory Southeast University Nanjing 210096 China department of communication engineering Nanjing Institute of Technology Nanjing 211167 China

By introducing a space-time coding scheme based on amicable orthogonality, we develop a distributed differential space-time coding scheme with the amplify-and-forward （AF） method for wireless cooperative networks. The scheme requires no knowledge of the channel state information at both transmitters and receivers, and effectively decreases the realization complexity due to no channel estimation. Moreover, it has lower decoding complexity and higher coding advantage than the existing scheme, thus avoiding the shortcoming of exponential decoding complexity of some existing schemes. According to the pairwise error probability （PEP） analysis of the system, the power allocations of source and relay terminals are jointly optimized, and as a result, the PEP is minimized, which will provide a helpful guideline for system design. Numerical calculation and simulation results show that the developed scheme is superior to the existing scheme. Moreover, the scheme with optimal power allocation yields obvious performance improvement over that with equal power allocation.

关键词： differential space-time coding cooperative communication amplify-and-forward method power allocation

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Quantitative Evaluation for Drawability of Sheet Metal

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Journal of Materials Science & technology 2005年第5期21卷 763-766页

作者： Zhiqing XIONG and Xuemei YANGdepartment of Mechanical engineering, nanjing institute of technology, nanjing 210013, china department of Mechanical engineering Nanjing Institute of Technology Nanjing 210013 China

The theoretical evaluating method is given for the drawability of the sheet with normal anisotropy. The general solution on the cracking load of deep-drawing is deduced, which is based on three kinds of hardening curve of materials most in use. The distributions of stress and strain in the deformed region and the drawing force are obtained by the numerical method. The limiting drawing ratio is calculated through computer-aided simulating test. The experiments of deep-drawing to four kinds of sheet metals express that the relative errors between the predictive and the experimental results about the cracking load and the limiting drawing ratio are within 5%. The drawability of common sheet metals can be quantitatively evaluated in precise terms by means of the theory and the method advanced in this paper.

关键词： Sheet forming Deep-drawing Formability Drawability

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A novel multicluster V-MIMO PCR scheme in large-scale Ad Hoc networks

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Science china(Information Sciences) 2010年第10期53卷 2097-2105页

作者： ZHOU Yao, CAI YueMing & PAN ChengKang department of Wireless communication, institute of communications engineering, PLA University of Science and technology, nanjing 210007, china 1. department of Wireless communication Institute of Communications Engineering PLA University of Science and Technology Nanjing 210007 China

A multicluster packet collision resolution (PCR) scheme is a kind of recently proposed virtualMIMO techniques. In existing multicluster PCR schemes, a large-scale wireless Ad Hoc network is divided into clusters and the single cluster PCR scheme is applied independently to resolve collisions in each cluster. However, there are still some flaws in existing multicluster PCR schemes. In this paper, by presenting a concise theoretical analysis model and a new CNS algorithm, a novel multicluster PCR scheme is proposed. Analysis and simulation results show that the proposed scheme can obtain high performance gain with low complexity. The proposed scheme is more robust and applicable than existing schemes.

关键词： packet collision resolution virtual-MIMO cooperative communication cooperative nodes selection

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A new sequential learning algorithm for RBF neural networks

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Science china(Technological Sciences) 2004年第4期47卷 447-460页

作者： YANG Ge1, LV Jianhong1 & LIU Zhiyuan2 1. department of Power engineering, Southeast University, nanjing 210096, china 2. department of Power engineering, nanjing institute of technology, nanjing 210013, china 1. department of Power engineering Southeast University 210096 Nanjing China 2. department of Power engineering Nanjing Institute of Technology 210013 Nanjing China

Due to their inherent imperfections, it is hard to use the static neural networks for nonlinear time-varying process modeling and prediction, and the minimal resource allocation network (MRAN) is difficult to be realized for its too many regulation parameters. A new sequential learning algorithm for radial basis function (RBF) neural networks based on local projection named Local Projection Network (LPN) is proposed in this paper. The results of validation for several benchmark problems with the new algorithm show that the presented LPN not only has the same level as M-RAN in network size and precision of the outputs, but also has fewer regulation parameters and is more predictable.

关键词： radial basis functions, local projection network, minimal resource allocation network, learning algorithm.

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Microstructure and Properties of Mg-12Gd-3Y-0.5Zr Alloys Processed by ECAP and Extrusion

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Journal of Wuhan University of technology(Materials Science) 2011年第6期26卷 1128-1132页

作者：朱荣 department of Materials Science and engineering Nanjing University of Science and Technology

Equal channel angular pressing （ECAP） processing and conventional extrusion （Ex） were applied to the Mg-12Gd-3Y-0.5Zr （wt%） magnesium alloy in order to evaluate the potential improvement in the mechanical properties. The ECAP experiment was conducted at 380 ℃ in a die having an included angle of 90° between two channels by the Bc route with the billet rotated by 90° about its longitudinal axis. Subsequently, some billets were processed by conventional extrusion at 300 ℃. The microstructures were examined by X-ray diffraction （XRD）, optical microscopy and transmission electron microscopy （TEM）. The experimental results indicate that the grain size is refined effectively, but the basal planes are highly inclined （about 40o） from the extrusion axis introduced by ECAP, which impairs the grain boundary strengthening effect. The conventional extrusion, following the ECAP, can modify the grains in hard orientation. Based on grain boundary strengthening due to ECAP and texture strengthening due to Ex, the strength is improved effectively. The enhanced activity of the non-basal slips, due to the refined grains and the reduction in c/a ratio, is responsible for good ductility and high strain hardening rate in samples obtained by the two-step process.

关键词： magnesium alloy equal channel angular pressing thermomechanical processing texture

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Preparation,crystal structure and quantum chemical investigation of[Li(NTO) (H_2O)_2]

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Chinese Science Bulletin 1999年第3期44卷 214-218页

作者： SONG Jirong , CHEN Zhaoxu , XIAO Heming , HU Rongzu and LI Fuping department of Chemical engineering, Northwest University, Xi’ an 710069, china department of Chemistry, nanjing University of Science and technology, nanjing 210094, china Xi’an Modern Chemistry Research institute, Xi’ an 710065, china department of Chemical engineering Northwest University Xi’an China department of Chemistry Nanjing University of Science and Technology Nanjing China Xi’an Modern Chemistry Research institute Xi’an China

[Li（NTO）(H2O2]was prepared by mixing the aqueous solution of 3-nitro-1,2,4-triazol-5-one （NTO） and lithium hydroxide. The crystal structure of [Li（NTO）（H2O）2] was determined by single crystal diffraction analysis. The crystal is monoclinic, space group P21/n with crystal parameters of α =0.7420（2） nm, b=0.344 9（1） nm, c=2.490 6（3） nm,β=94.89（1）°, Z=4, Dc=1.799 ***-3, V=0.635 nm3,μ= 1.591 cm-1, F（000） = 392. The final R is 0.051. The MNDO MO calculation shows that the coordinate bonds of title compound possess certain extent of covalent character. O2 atom of NTO anion is bonded to Li atom; the nitro group will be lost first when NTO is decomposed.

关键词： NTO lithium coordination crystal structure MNDO MO method.

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Performance of iteratively decoded bit-interleaved coded modulation with chaos based interleaving strategies

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Science china(Information Sciences) 2010年第4期53卷 833-841页

作者： ZOU XueLan1*, LIU WeiYan2 & FENG GuangZeng3 1department of Electronic and Information engineering, Zhejiang institute of Media and communications, Hangzhou 310018, china 2department of Information engineering, Jiangsu City Vocation College, nanjing 210036, china 3College of communication and Information engineering, nanjing University of Posts and Telecommunications, nanjing 210003, china 1. department of Electronic and Information engineering Zhejiang Institute of Media and Communications Hangzhou 310018 China2. Department of Information Engineering Jiangsu City Vocation College Nanjing 210036 China3. College of Communication and Information Engineering Nanjing University of Posts and Telecommunications Nanjing 210003 China

Bit-interleaved coded modulation with iterative decoding (BICM-ID) is a bandwidth efficient trans- mission scheme which is well suitable for next-generation mobile communications. The interleaver design is critical to the high performance of BICM-ID. In this paper we investigate the application of the chaos theory to the interleaver design to further improve the performance of BICM-ID. A new interleaving scheme based on the chaos theory is proposed. Compared with the random interleaver, the proposed approach has the ad- vantages including lower system delay and higher transmission efficiency. Simulation results in both additive white Gaussian noise (AWGN) channel and Rayleigh fading channel are provided, which demonstrates that the new interleaver is better than the random interleaver and exhibits excellent performance when applied to the BICM-ID system.

关键词： chaos interleaving bit-interleaved coded modulation (BICM) iterative decoding

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Game model of safety monitoring for arch dam deformation

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Science china(Technological Sciences) 2008年第S2期51卷 76-81页

作者： SU HuaiZhi1,2,WU ZhongRu1,2,GU YanChang1,2,HU Jiang1 & WEN ZhiPing3 1 College of Water Conservancy and Hydropower engineering,Hohai University,nanjing 210098,china 2 National engineering Research Center of Water Resources Efficient Utilization and engineering Safety,nanjing 210098,china 3 department of Computer engineering,nanjing institute of technology,nanjing 210013,china College of Water Conservancy and Hydropower engineering Hohai University Nanjing 210098 China National engineering Research Center of Water Resources Efficient Utilization and engineering Safety Nanjing 210098 China department of Computer engineering Nanjing Institute of Technology Nanjing 210013 China

Arch dam deformation is comprehensively affected by water pressure,temperature,dam's structural behavior and material properties as well as other *** them the water pressure and temperature are external factors(source factors) that cause dam deformation,and dam's structural behavior and material properties are the internal factors of deformation(resistance factors).The dam deformation is the result of the mutual game playing between source factors and resistance ***,resistance factors of structure and materials that reflect resistance character of arch dam structure are introduced into the traditional model,where structure factor is embodied by the flexibility coefficient of dam body and the maximum dam height,and material property is embodied by the elastic modulus of *** the basis of analyzing the correlation between dam deformation and resistance factors,the game model of safety monitoring for arch dam deformation is put forward.

关键词： arch dam deformation monitoring model flexibility coefficient game theory

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Structure and Pozzolanic Activity of Calcined Coal Gangue during the Process of Mechanical Activation

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Journal of Wuhan University of technology(Materials Science) 2009年第2期24卷 326-329页

作者：郭伟 department of Material engineering Yancheng Institute of Technology institute of Material Science and engineering Nanjing University of Technology

On the basis of analyzing coal gangue＇s chemical and mineral compositions, the structure change of coal gangue during the mechanical activation was investigated by XRD, FTIR, NMR, and the mechanical strength of the cement doped coal gangue with various specific surface area was tested. The experimental results indicate that, the lattice structure of metakaolin in coal gangue samples calcined at 700 ℃ disorganizes gradually and becomes disordered, and the lattice structure of α-quartz is distorted slightly. The pozzolanic activity of the coal gangue increases obviously with its structural disorganization.

关键词： coal gangue mechanical activation structure NMR tetrahedron

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引用

Science china Chemistry 2004年第6期47卷 466-479页

作者： SONG Huajie1,2, XIAO Heming1 & DONG Haishan2 1. department of Chemistry, nanjing University of Science and technology, nanjing 210094, china 2. institute of Chemical Materials, china Academy of engineering Physics, Mianyang 621900, china 1. department of Chemistry Nanjing University of Science and Technology 210094 Nanjing China 2. institute of Chemical Materials China Academy of Engineering Physics 621900 Mianyang China

The symmetry-adapted perturbation theory (SAPT) that has the ability in decompo- sition of the total interaction energy into physically meaningful components is used to provide a more fundamental understanding of intermolecular forces. This work was motivated by the diffi- culty of standard SAPT in computing the intermolecular interactions for large energetic dimer systems. SAPT based on Kohn-Sham orbitals (SAPT(DFT)) proves computationally efficient for these large systems, but has been shown to perform poorly for interaction energy components. The deficiencies of SAPT(DFT) result from wrong asymptotical behaviors of commonly used exchange-correlation potentials. To remove the deficiencies, two asymptotic corrections by means of van Leeuwen and Baerends (LB) model potential and Fermi-Amaldi (FA) type potential were applied into three small test systems comprising He2, HF2 and (N2)2 and a set of larger ni- tramide dimers at several separations. The results showed that when utilizing newly developed frequency-dependent density susceptibilities (FDDS) technique for computing dispersion energy, the FA asymptotic correction is very effective to circumvent these deficiencies in SAPT(DFT) and yields a good accuracy over the LB correction. The FA corrected SAPT(DFT) approach is capa- ble of correctly predicting all the quantitative trends in binding energies for all test cases and substantially reduces computational cost as compared with the standard SAPT calculations. The successful application of the approach to nitramide dimer demonstrates that it potentially pro- vides a good means to calculate accurately intermolecular forces in larger system such as en- ergetic systems.

关键词： intermolecular interaction, density functional theory (DFT), symmetry adapted perturbation theory (SAPT), asymptotic correction, frequency-dependent density susceptibilities (FDDS).

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