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( Haiwen Li ),( Xiukun Ren ),( Ting Bai ),( Long Zhang ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.12
A single snapshot data can only provide limited amount of information so that the rank of covariance matrix is not full, which is not adopted to complete the parameter estimation directly using the traditional super-resolution method. Aiming at solving the problem, a joint time delay and angle estimation using matrix pencil method based on information reconstruction vector for orthogonal frequency division multiplexing (OFDM) signal is proposed. Firstly, according to the channel frequency response vector of each array element, the algorithm reconstructs the vector data with delay and angle parameter information from both frequency and space dimensions. Then the enhanced data matrix for the extended array element is constructed, and the parameter vector of time delay and angle is estimated by the two-dimensional matrix pencil (2D MP) algorithm. Finally, the joint estimation of two-dimensional parameters is accomplished by the parameter pairing. The algorithm does not need a pseudo-spectral peak search, and the location of the target can be determined only by a single receiver, which can reduce the overhead of the positioning system. The theoretical analysis and simulation results show that the estimation accuracy of the proposed method in a single snapshot and low signal-to-noise ratio environment is much higher than that of Root Multiple Signal Classification algorithm (Root-MUSIC), and this method also achieves the higher estimation performance and efficiency with lower complexity cost compared to the one-dimensional matrix pencil algorithm.
Miniaturized Bandstop Filter Using Meander Spurline and Capacitively Loaded Stubs
Haiwen Liu,Reinhard Knoechel,Klaus Schuenemann 한국전자통신연구원 2007 ETRI Journal Vol.29 No.5
A miniaturized bandstop filter (BSF) is introduced in this paper. The filter consists of one meander spurline and a pair of capacitively loaded stubs. The meander spurline with low resonant frequency and improved slowwave factor exhibits excellent resonant bandgap characteristics which can be modeled by a longitudinally coupled resonator. The design of the proposed microstrip BSF is presented, and its performance is measured. Measurements show that there is a stopband from 2.3 to 5.6 GHz with S21 less than –20 dB. The total length of this BSF equals 23 mm.
Quad-Band Bandpass Filter Using Quad-Mode Stub-loaded Resonators
Haiwen Liu,Xiaomei Wang,YAN WANG,Shen Li,Yulong Zhao,Xuehui Guan 한국전자통신연구원 2014 ETRI Journal Vol.36 No.4
Compact multi-band bandpass filters using quad-mode stubloadedresonators are proposed in this letter. Firstly, a novelapproach about the mode-splitting characteristics of thequadruple-mode resonator is investigated, which can providedual-band behavior. Secondly, a quad-band filter is proposedand designed by cascading two quadruple-mode resonators;the upper one operates at 1.8/2.4 GHz (GSM- and WiMaxband)and the lower one at 1.57/2.1 GHz (GPS- and WCDMAband). Finally, the proposed filters have been fabricated. Respectable agreement between simulation and measurementverifies the validity of this design methodology.
Compact Dual-Wideband Bandpass Filter with Multimode Resonator
Haiwen Liu,Shen Li,Xuehui Guan,Baoping Ren,Jiuhuai Lei,yanwang 한국전자통신연구원 2014 ETRI Journal Vol.36 No.1
A microstrip dual-wideband bandpass filter using amultimode resonator (MMR) is proposed in this letter. Theproposed MMR loaded with a T-shaped open-ended stub and ashort-ended stub exhibits triple mode characteristics, and asynthesis method is developed to illustrate the wide passbandwith independently controllable center frequencies andbandwidths. To verify this design methodology, a dualwidebandfilter with fractional bandwidths of 19.1% and27.9% is designed and fabricated. The measured results agreewith the simulations.
Factor Endowment, the Choice of Technology, and the Volume of Trade
Haiwen Zhou 한국국제경제학회 2007 International Economic Journal Vol.21 No.4
This paper studies impacts of factor endowment on international trade in a general equilibrium model in which firms choose their technologies endogenously. Though countries only differ in factor endowment ex ante, countries may also differ in their chosen technologies. If industries choose different capital-labor intensities in equilibrium, the Heckscher-Ohlin theorem, factor price equalization theorem, the Rybczynski theorem, and the Stolper-Samuelson theorem hold. If industries choose the same capital-labor intensity in equilibrium, the volume of trade is zero. None of the four theorems applies.
The Choice of Technology and Economic Geography
Zhou Haiwen 한국국제경제학회 2022 International Economic Journal Vol.36 No.1
Empirical evidence shows that firms located in regions with larger population size are on average larger and more productive. To explain this empirical observation, firms producing intermediate goods are assumed to choose their technologies with different levels of fixed and marginal costs. In this general equilibrium model of economic geography, intermediate good producers engage in oligopolistic competition. The model is tractable and leads to interesting and analytical results. An intermediate good producer in the region with a higher population produces a higher level of output and has a lower marginal cost of production regardless of the existence of regional trade. With regional trade, if a worker moves from the region with a lower number of workers to the region with a higher number of workers, intermediate good producers in both regions choose less advanced technologies.
FINITE ELEMENT MODELING FOR CONCRETE RANDOM PARTICLE MODEL
YanHui Yin,HaiWen Wang 한국멀티미디어학회 2006 한국멀티미디어학회 국제학술대회 Vol.2006 No.-
How to select the reasonable aggregate based on the engineering need and the actual condition of the locality and perform effectually computational simulation base on the type of the aggregate is important. This paper generalize the affection of all kinds of parameters of the aggregate to the concrete function base on the importance of concrete aggregate and lots of engineering background. The geometrical representation and finite element mesh of concrete random particle model are all generated automatically in this paper.
Zhiqiang Zheng,Yongxin Liu,Haiwen Yuan,Qiusheng Wang 제어·로봇·시스템학회 2012 International Journal of Control, Automation, and Vol.10 No.3
This note developed a distributed fault detection and isolation scheme for a class of large-scale systems in discrete-time framework. The unstructured modeling uncertainty and abrupt and incipient faults are considered in this scheme. By using overlapping decompositions, the large-scale system is decomposed into a set of subsystems which are monitored by a network of local fault detectors (LFDs) and local fault isolation estimators (LFIEs). Specially, the LFIEs, corresponding the faults af-fecting the common components among different subsystems, may reach a cooperative (or consensus) isolation decision, based on the fact that they can exchange some knowledge about the local information of system by suitable communication links. As a result, for these LFIEs, the capability of isolating faults may be improved. Moreover, the derivation of rigorous analytical results for the detectability and isolability properties of the proposed scheme is given. Simulation results are provided to show the effectiveness of the presented scheme.
Frequency Regulation Strategy for AC–DC System During Black Start
Chengjun Xia,Jiazheng Xie,Haiwen Lan,Baorong Zhou,Zhaobin Du 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.1
High-voltage direct current (HVDC) can speed up the recovery of a power system. However, both rectifer and inverter sides of HVDC are weak systems during a black start. To coordinate frequency characteristics of both sides within the frequency deviation constrain, a frequency regulation strategy for AC–DC system during a black start is proposed. First, the mathematical models of asynchronous interconnected AC–DC system are established, and the optimal HVDC transmission power leading to minimum frequency deviation of both sides is obtained based on the linear quadratic optimal control method. To adapt to the continuously changing parameters and confgurations of the AC power system during a black start, a Narendra adaptive tracking control method is developed to obtain the control law of the target value of governor, which allows the actual system frequency follow the reference system frequency under the optimal HVDC transmission power. Finally, the simulation model is established using PSCAD/EMTDC software to verify the proposed strategy