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Search Results: 1 - 10 of 152784 matches for " Li Zhao "
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A Gauss-Newton-Based Broyden’s Class Algorithm for Parameters of Regression Analysis  [PDF]
Xiangrong Li, Xupei Zhao
Applied Mathematics (AM) , 2011, DOI: 10.4236/am.2011.21005
Abstract: In this paper, a Gauss-Newton-based Broyden’s class method for parameters of regression problems is presented. The global convergence of this given method will be established under suitable conditions. Numerical results show that the proposed method is interesting.
A hybrid conjugate gradient method for optimization problems  [PDF]
Xiangrong Li, Xupei Zhao
Natural Science (NS) , 2011, DOI: 10.4236/ns.2011.31012
Abstract: A hybrid method of the Polak-Ribière-Polyak (PRP) method and the Wei-Yao-Liu (WYL) method is proposed for unconstrained optimization pro- blems, which possesses the following properties: i) This method inherits an important property of the well known PRP method: the tendency to turn towards the steepest descent direction if a small step is generated away from the solution, preventing a sequence of tiny steps from happening; ii) The scalar holds automatically; iii) The global convergence with some line search rule is established for nonconvex functions. Numerical results show that the method is effective for the test problems.
Beacon-driven Leader Based Protocol over a GE Channel for MAC Layer Multicast Error Control  [PDF]
Zhao LI, Thorsten HERFET
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2008, DOI: 10.4236/ijcns.2008.12019
Abstract: In wireless networks current standard MAC layer protocols don’t provide any error correction scheme for broadcast/multicast. In this paper, we enhance a Leader Based Protocol (LBP) and propose a Beacon-driven Leader Based Protocol (BLBP) for the MAC layer multicast error control. To guarantee a very low Packet Loss Ratio (PLR) under strict delay constraints for video multicast over a Gilbert-Elliott (GE) channel, we analyze BLBP and compare it with LBP and different application layer multicast error control schemes via simulation experiments. Both the theoretical analysis and simulation results show that BLBP can correct nearly all the errors for all receivers in the MAC layer and is more efficient than LBP. BLBP is also more efficient than the application layer Automatic Repeat request (ARQ) scheme and the total multicast delay is much shorter. BLBP is very good for real-time multicast applications with strict delay constraints.
Energy-Constrained Duty-Cycle Optimization for Wireless Implanted Communication Devices  [PDF]
Zhao Xu, Ye Li
E-Health Telecommunication Systems and Networks (ETSN) , 2012, DOI: 10.4236/etsn.2012.11002
Abstract: Energy minimization is an important goal in wireless implanted communication devices. In this context, a cross-layer method is used to optimize parameters in different layers of OSI model, but, there are still several challenges affecting the optimization algorithm. The first point is the accurate energy model, and the second point is the suitable channel model exclude traditional free space channel model. In this paper, we establish a system level accurate energy consumption model and build a suitable channel model for implanted communication devices; analysis the energy-constrained duty cycle optimization with a cross-layer method. Simulation results reveal that adaptive duty cycle to minimize the energy consumption of the wireless implanted communication system is implemented based on accurate energy consumption model and channel model. Simulation results show a good performance on energy saving.
Optimal Spinning Reserve for Power System with Wind Integrated  [PDF]
Longlong Li, Dongmei Zhao
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.54B193

This paper presents an evolutionary stochastic production simulation to solve the optimal spinning reserve configuration problem in power system with wind integrated. Equivalent load curve is generated with considering the wind power forecasting deviation and generation scheduling of hydropower plant in different water periods. The equivalent load duration curve (ELDC), redrawn from equivalent load curve is the core of stochastic production simulation which focuses on random outage of generator and load fluctuation. The optimal spinning reserve model is established around the reliability index Expected Energy Not Served (ENNS). The optimal scheduling of spinning reserve is reached while the cost of purchasing spinning reserve is equal to the outage loss. At last, results of the optimal spinning reserve model tested in Hainan power grid help reduce the costs of spinning reserve configuration.

An Optimal Dynamic Generation Scheduling for a Wind-Thermal Power System  [PDF]
Xingyu Li, Dongmei Zhao
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.54B194

In this paper, a dynamic generation scheduling model is formulated, aiming at minimizing the costs of power generation and taking into account the constraints of thermal power units and spinning reserve in wind power integrated systems. A dynamic solving method blended with particle swarm optimization algorithm is proposed. In this method, the solution space of the states of unit commitment is created and will be updated when the status of unit commitment changes in a period to meet the spinning reserve demand. The thermal unit operation constrains are inspected in adjacent time intervals to ensure all the states in the solution space effective. The particle swarm algorithm is applied in the procedure to optimize the load distribution of each unit commitment state. A case study in a simulation system is finally given to verify the feasibility and effectiveness of this dynamic optimization algorithm.

Power Line Monitoring Data Transmission Using Wireless Sensor Network  [PDF]
Lifen Li, Huaiyu Zhao
Journal of Power and Energy Engineering (JPEE) , 2015, DOI: 10.4236/jpee.2015.38008
Abstract: The WSN used in power line monitoring is long chain structure, and the bottleneck near the Sink node is more obvious. In view of this, A Sink nodes’ cooperation mechanism is presented. The Sink nodes from different WSNs are adjacently deployed. Adopting multimode and spatial multiplexing network technology, the network is constructed into multi-mode-level to achieve different levels of data streaming. The network loads are shunted and the network resources are rationally utilized. Through the multi-sink nodes cooperation, the bottlenecks at the Sink node and its near several jump nodes are solved and process the competition of communication between nodes by channel adjustment. Finally, the paper analyzed the method and provided simulation experiment results. Simulation results show that the method can solve the funnel effect of the sink node, and get a good QoS.
On Two Birkhoff-Type Interpolations with First- and Second-Order Derivative  [PDF]
Tinggang Zhao, Yongjun Li
Journal of Applied Mathematics and Physics (JAMP) , 2016, DOI: 10.4236/jamp.2016.47133
Abstract: In this paper, we consider two interpolations of Birkhoff-type with integer-order derivative. The Birkhoff interpolation is related with collocation method for the corresponding initial or boundary value problems of differential equations. The solvability of the interpolation problems is proved. For Gauss-type interpolating points, error of interpolation approximation is deduced. Also, we give efficient algorithms to implement the concerned interpolations.
The Quasi-Order of Matching Energy of Circum Graph with Chord  [PDF]
Ning Zhao, Yinkui Li
Applied Mathematics (AM) , 2017, DOI: 10.4236/am.2017.88088
Abstract: The matching energy of graph G is defined as \"\" , where \"\" be the roots of matching polynomial of graph G. In order to compare the energies of a pair of graphs, Gutman and Wager further put forward the concept of quasi-order relation. In this paper, we determine the quasiorder relation on the matching energy for circum graph with one chord.
The Comparative Research on the Location Technology of Wireless Sensor Networks  [PDF]
Jijun ZHAO, Hua LI, Xin ZHAO
Communications and Network (CN) , 2009, DOI: 10.4236/cn.2009.12018
Abstract: Wireless Sensor Network (WSN) which is composed of lots of self-organizational intelligence nodes has become new technology of information acquisition and processing. Location technology is one of the key technologies in WSN. There are many kinds of location algorithms currently and the research to performance evaluation and applicability analysis of algorithms has fundamental significance. For this reason, the paper firstly elaborated the performance evaluation indexes of location algorithms, and analyzed the location prin-ciples, characteristics and current fundamental problems to typical and some new location algorithms, and then analyzed and compared some typical location algorithms according to the location accuracy, node den-sity and hardware requirement, obtaining the sphere of application of these algorithms and pointing out the problems which need to be solved in WSN currently.
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