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Energy Efficiency Maximization Design for Full-Duplex Cooperative NOMA Systems With SWIPT

IEEE ACCESS 2019年 7卷 20442-20451页

作者： Huang, He Zhu, Min Wenzhou Vocat & Tech Coll Dept Informat Technol Wenzhou 325000 Peoples R China Zhejiang Shuren Univ Coll Informat Sci & Technol Hangzhou 310009 Zhejiang Peoples R China

This paper investigates non-orthogonal multiple access (NOMA) system, where the near NOMA user is able to communicate with a base station (BS) directly while the far NOMA user needs to resort to a full-duplex (FD) relay. Wireless power transfer is applied to our system where the FD relay integrated with power splitting architecture can be powered wirelessly by the ambient radio signals simultaneously. Moreover, we assume that self-interference cancellation at the relay and inter-user interference cancellation at the near NOMA user are imperfect. For the purpose of maximizing the energy efficiency of the NOMA system, the power splitting ratio and transmit beamforming vectors are researched for the BS and relay with the guarantee of QoS requirements for two users. The formulated problem appears to be nonlinear fractional programming, which is highly nonconvex and the global optimality is hard to obtain. By introducing Charnes-Cooper's transformation and inner approximation method, we develop an iterative algorithm to gain the near optimal solution. The simulation results show that the proposed joint optimizing algorithm outperforms the existing scheme in terms of energy efficiency as well as the effect of SI cancellation on performance gain.

关键词： Non-orthogonal multiple access (NOMA) full-duplex relay power splitting fractional programming iterative algorithm

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Improved Equivalent Source Method to Predict Sound Scattered by Solid Surfaces

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AIAA JOURNAL 2019年第2期57卷 513-520页

作者： Xu, Chen Mao, Yijun Hu, Zhiwei Univ Southampton Southampton SO17 1BJ Hants England Xi An Jiao Tong Univ Xian 710049 Shaanxi Peoples R China

The equivalent source method is an efficient numerical method to predict sound scattered by solid surfaces. Compared with the conventional boundary element method, the equivalent source method has inherent advantages in avoiding the problems of singularity and nonuniqueness of the solution. However, the equivalent source method can form an ill-conditioned matrix for some specific cases, such as thin scattering surfaces, resulting in serious computational errors in these situations. In this paper, an improved equivalent source method is developed in which an efficient regularization method is proposed to reduce the condition number of the coefficient matrix and the regularization parameter can be easily determined. Numerical test cases validate that the improved method usually can reach a satisfactory computational accuracy for predicting sound scattered by thin structures.

关键词： Boundary Integral Equation Singular Value Decomposition Acoustic Scattering iterative algorithm Frequency Domain Green's Function Airframes Genetic algorithm Aeroengine

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Nonsingular Dual-Primal algorithm for Fuel-Optimal Impulsive Rendezvous

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2019年第4期42卷 737-751页

作者： Kim, Youngkwang Park, Sang-Young Yonsei Univ Astrodynam & Control Lab Dept Astron Seoul 03722 South Korea

This paper addresses a fuel-optimal impulsive rendezvous problem for minimizing the total characteristic velocity. In previous research, the authors proposed an efficient dual-primal optimization algorithm for this problem, taking advantage of the primal and dual formulations at once. Although the dual-primal optimization algorithm is capable of computing the accurate global-optimal trajectory for most cases, it cannot solve the nontrivial primer vector cases in which the optimal impulse timings (that is, the time points at which the optimality conditions are satisfied) are not identical to the time points of the optimal impulses (that is, the time points at which the impulses are applied in the optimal trajectory). The main contributions of this paper are 1) development of a novel strategy resolving the nontrivial primer vectors for general dual-first approaches, and 2) development of a new nonsingular dual-primal optimization algorithm adopting the strategy. The new algorithm generates an impulse sequence set including the possible combinations of time points of impulses, and then it searches through the impulse sequence set to find the primal root. To demonstrate its nontriviality resolution capability, the rendezvous problems near circular and elliptical orbits are solved for five test cases, and the newly developed algorithm succeeds in resolving nontrivial primer vectors.

关键词： Fuels Optimization algorithm Elliptical Orbit Computing Characteristic Velocity Lagrange Multipliers Orbital Elements Trajectory Optimization iterative algorithm Sparse Nonlinear Optimizer

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Optimization of an Autonomous Hybrid Renewable Energy System Using Reformed Electric System Cascade Analysis

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IEEE TRANSACTIONS ON INDUSTRIAL INFORMATICS 2019年第1期15卷 399-409页

作者： Singh, Ranjay Bansal, Ramesh C. Univ Pretoria Dept Elect Engn & Comp Engn ZA-0028 Hatfield South Africa

This paper presents reformed electric system cascade analysis (RESCA) technique for optimization of hybrid renewable energy system (HRES) comprising of wind energy conversion system (WECS), photovoltaic (PV) system, battery energy storage system, and nonintermittent source (NIS). Optimization constraints of final excess energy, energy generation ratio, cost of energy, net present cost (NPC), and renewable energy fraction are considered for the optimization of the system. This optimization is realized for an isolated load comprising of the ten households in Malaysia with a daily consumption of 84.5 kWh. On successful implementation of RESCA with different constraints, it is found that the optimum size of energy sources for the HRES varies depending on the chosen constraints. Also, the NPC of the system can be considerably reduced on introduction of NIS to the HRES. RESCA provides the user with better insight into the influence of variation of PV and WECS power generation while identifying the optimal size of energy storage unit. The optimized results obtained are also compared with benchmark HOMER software to validate the methodology.

关键词： Batteries design optimization hybrid power system iterative algorithm solar energy wind energy

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A Numerical Approach To Generalized Periodic Sylvester Matrix Equation

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ASIAN JOURNAL OF CONTROL 2019年第5期21卷 2468-2475页

作者： Lv, Lingling Zhang, Zhe North China Univ Water Resources & Elect Power Inst Elect Power Zhengzhou 450011 Henan Peoples R China

The paper is dedicated to solving the generalized periodic discrete-time Sylvester matrix equation, which is frequently encountered in control theory and applied mathematics. An iterative algorithm for this equation is presented. The proposed method is developed from a point of least squares method. The rationality of the method is testified by theoretical analysis. The presented approach is numerically reliable and requires less computation. Two numerical examples illustrate the effectiveness of the raised results.

关键词： Generalized periodic Sylvester matrix equations least squares method iterative algorithm numerical solutions

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Energy efficient joint energy cooperation and power allocation in multiuser distributed antenna systems with hybrid energy supply

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IET COMMUNICATIONS 2019年第2期13卷 153-161页

作者： Zhu, Pengcheng Mao, Huanhuan Li, Jiamin You, Xiaohu Southeast Univ Natl Mobile Commun Res Lab Nanjing 210096 Jiangsu Peoples R China

This study investigates the joint power allocation and energy cooperation problem in a multiuser downlink distributed antenna system with hybrid energy supply. The authors focus on the energy efficiency (EE) maximization problem for three different types of precoding, zero-forcing (ZF), general beamforming method and conjugate-beamforming. For ZF precoding, they apply fractional programming and reform the optimization problem to a convex one. An iterative algorithm to deal with the fractional objective function is presented. Whereas the problem is non-convex for general beamforming with user interference, they take maximum ratio transmission as an example and adopt a set of transformation and approximation based on the difference of convex (DC) programming. Furthermore, for conjugate-beamforming, they first transform the quadratic signal to interference plus noise power ratio into a trackable form and then DC programming is applied. A two-loop algorithm for the general beamforming and conjugate-beamforming is presented with fractional programming in the inner loop and DC programming in the outer loop. Simulations show that the proposed algorithm improved EE significantly and indicate that energy cooperation can contribute to a higher EE. It also reveals that ZF achieves better EE with small noise variance while conjugate beamforming in high noise circumstance.

关键词： telecommunication power management precoding concave programming convex programming radiofrequency interference energy conservation antenna arrays iterative methods array signal processing multi-access systems approximation theory noise variance while conjugate beamforming energy efficient joint energy cooperation hybrid energy supply multiuser downlink energy efficiency maximisation problem general beamforming method conjugate-beamforming ZF precoding user interference fractional programming optimisation problem fractional objective function convex programming interference plus noise power ratio DC programming multiuser distributed antenna systems smart grid joint power allocation and energy cooperation problem iterative algorithm nonconvex problem maximum ratio transmission quadratic signal to interference plus noise power ratio two-loop algorithm

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Reliability analysis of standby systems with multi-state elements subject to constant transition rates

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QUALITY AND RELIABILITY ENGINEERING INTERNATIONAL 2019年第1期35卷 318-328页

作者： Jia, Heping Levitin, Gregory Ding, Yi Song, Yonghua Zhejiang Univ Coll Elect Engn Hangzhou Zhejiang Peoples R China Israel Elect Corp Ltd Haifa Israel Univ Macau Dept Elect & Comp Engn Macau Peoples R China

Standby redundancy has been extensively applied to critical engineering systems to enhance system reliability. Researches on reliability evaluation for standby systems focus more on systems with binary-state elements. However, multi-state elements with different performances have played a significant role in engineering systems. This paper presents an approach for reliability analysis of standby systems composed of multi-state elements with constant state transition rates and absorbing failure states. The approach allows modelling different standby systems beyond cold, warm and hot ones by taking into account differences in possible maintenance of elements in standby and operation modes and dependence of elements' operational behavior on their initial state at the time of activation. An iterative algorithm for reliability evaluation based on element state probabilities is suggested. Illustrating examples of evaluating reliability of different types of homogeneous and heterogeneous standby systems are demonstrated.

关键词： constant transition rates iterative algorithm multi-state elements reliability analysis standby systems

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Finite iterative Hamiltonian solutions of the generalized coupled Sylvester - conjugate matrix equations

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TRANSACTIONS OF THE INSTITUTE OF MEASUREMENT AND CONTROL 2019年第4期41卷 1139-1148页

作者： Bayoumi, Ahmed M. E. Ain Shams Univ Dept Math Fac Educ Cairo Egypt

In this paper, we present an iterative algorithm to solve a generalized coupled Sylvester - conjugate matrix equations over Hamiltonian matrices. When the considered systems of matrix equations are consistent, it is proven that the solution can be obtained within finite iterative steps for any arbitrary initial generalized Hamiltonian matrices in the absence of round off errors. Two numerical examples are given to illustrate the effectiveness of the proposed method.

关键词： Coupled Sylvester - conjugate matrix equation iterative algorithm inner product Frobenius norm Hamiltonian solutions

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PySCF-NAO: An efficient and flexible implementation of linear response time-dependent density functional theory with numerical atomic orbitals

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COMPUTER PHYSICS COMMUNICATIONS 2019年 236卷 188-204页

作者： Koval, Peter Barbry, Marc Sanchez-Portal, Daniel Univ Basque Country CSIC Ctr Fis Mat Paseo Manuel de Lardizabal 5 Donostia San Sebastian 20018 Spain Donostia Int Phys Ctr Paseo Manuel de Lardizabal 4 Donostia San Sebastian 20018 Spain

We present an algorithm and its implementation to calculate the properties of electronic excitations in molecules and clusters from first principles, using time-dependent density functional theory (TDDFT). The algorithm assumes the use of some localized functions as a basis set to represent the spatial degrees of freedom. It relies on an iterative computation of the induced density according to the Dyson-like equation for the linear response function. The current implementation is built upon so-called numerical atomic orbitals. It is suitable for a wide variety of density functional theory (DFT) software. In this work, we demonstrate TDDFT calculations starting from preceding DFT runs with SIESTA, GPAW and PySCF packages, while a coupling with the other DFT packages such as Fireball and OpenMX is planned. The mentioned packages are capable of performing ab initio molecular dynamics simulations, and the speed of our TDDFT implementation makes feasible to perform a configuration average of the optical absorption spectra. Our code is written mostly in Python language allowing for a quick and compact implementation of most numerical methods and data-managing tasks with the help of NumPy/SciPy libraries and Python intrinsic constructs. Part of the code is written in C and Fortran to achieve a competitive speed in particular sections of the algorithm. Many parts of the current algorithm and implementation are useful in other ab initio methods for electronic excited states, such as Hedin's GW, Bethe-Salpeter equation and DFT with hybrid functionals. Corresponding proof-of-principles implementations are already part of the code. Program summary Program Title: PySCF-NAO Program Files doi: http://***/10.17632/9wgp6255hn.1 Licensing provisions: Apache License, Version 2.0 Programming language: Python (2 or 3), Fortran90 and C Supplementary material: We provide the source code and input files to organize example and benchmark calculations discussed in the paper. Nature o

关键词： Numerical atomic orbitals Dominant product basis Time-dependent density functional theory iterative algorithm

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Disturbance-observer-based LQR control of singularly perturbed systems via recursive decoupling methods

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INTERNATIONAL JOURNAL OF SYSTEMS SCIENCE 2019年第4期50卷 764-776页

作者： Xu, Jing Niu, Yugang East China Univ Sci & Technol Minist Educ Key Lab Adv Control & Optimizat Chem Proc Shanghai 200237 Peoples R China

This paper addresses the disturbance-observer-based linear quadratic regulation (LQR) problem of singularly perturbed systems subject to harmonic disturbances. To reduce the computational burden and facilitate the on-board implementation, a recursive matrix decoupling method is proposed to decompose the stiff singularly perturbed model into the block-diagonal form. Then, a robust LQR controller is designed based on the equivalent decoupled system, which consists of a state feedback controller for performance optimisation and a robust controller for disturbance compensation. Moreover, the designed controller is integrated with a finite frequency disturbance observer to attenuate the effect of harmonic disturbances. Finally, a simulation example on a DC motor system is provided to verify the effectiveness of the proposed design method.

关键词： Disturbance observer iterative algorithm LQR control singularly perturbed systems

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