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Transmit Beamforming and Integer Matrix Design for MISO SWIPT Systems With Integer Forcing

IEEE WIRELESS COMMUNICATIONS LETTERS 2019年第1期8卷 229-232页

作者： Tung, Sangwon Lee, Jang-Won Lee, Chungyong Yonsei Univ Sch Elect & Elect Engn Seoul 03722 South Korea

This letter considers simultaneous wireless information and power transfer (SWIPT) in multiple-input single-output broadcasting systems based on the integer forcing (IF) technique where multiple receivers are equipped with a power splitting circuit and able to harvest energy and decode information at the same time. The optimization problem that incorporates the beamforming matrix and IF coefficients matrix designs is formulated to minimize the transmit power at transmitter, while guaranteeing the achievable rate and harvested energy threshold of each receiver. To tackle the NP-hardness and non-convexity of the optimization problem, we propose an iterative algorithm consisting of two sub-problems. Simulation results provide the comparison of the performance of SWIPT systems with and without IF technique.

关键词： Simultaneous wireless information and power transfer (SWIPT) integer forcing optimization problem iterative algorithm

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Robust check loss-based inference of semiparametric models and its application in environmental data

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JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS 2020年 365卷 112267-000页

作者： Yang, Jing Lu, Fang Lu, Xuewen Hunan Normal Univ Coll Math & Stat Minist Educ China Key Lab High Performance Comp & Stochast Informat Changsha 410081 Hunan Peoples R China Univ Calgary Dept Math & Stat Calgary AB T2N 1N4 Canada

Composite quantile regression has been shown to be a more competitive method than the well-known mean regression and quantile regression approaches, since it can significantly improve the estimation efficiency for a wide class of errors. In this paper, we propose a profiling composite quantile regression for robust estimation of semiparametric varying-coefficient partially linear model (VCPLM) by combining the ideas of local linear composite quantile regression with the profile technique. Different from the step-wise estimation method considered in Kai et al. (2011), an iterative algorithm is developed for the estimates of parametric and nonparametric functions. Under some mild regularity conditions, we establish the asymptotic normalities of the obtained estimators and further briefly discuss the related asymptotic relative efficiency. Noteworthy, an entirely different way from Kai et al. (2011) is presented to establish the asymptotic normality of the parametric component, which is frequently of the primary interest in VCPLM. Some Monte Carlo simulations with various errors and an environmental data application are conducted to evaluate the finite sample performance of the proposed methodology. (C) 2019 Published by Elsevier B.V.

关键词： Varying coefficient partially linear model Robust inference iterative algorithm Asymptotic properties Environmental data

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Nonconvex L1/2 Minimization Based Compressive Sensing Approach for Duct Azimuthal Mode Detection

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AIAA JOURNAL 2020年第9期58卷 3932-3946页

作者： Bai, Baohong Li, Xiaodong Zhang, Tao Lin, Dakai Tsinghua Univ Sch Aerosp Engn Beijing 100084 Peoples R China Beihang Univ Sch Energy & Power Engn Beijing 100191 Peoples R China Commercial Aircraft Corp China Ltd Beijing Aircraft Technol Res Inst Dept Aerodynam & Acoust Beijing 102211 Peoples R China China Aerodynam Res & Dev Ctr Key Lab Aerodynam Noise Control Mianyang 621000 Sichuan Peoples R China Beijing Key Lab Simulat Technol Civil Aircraft De Beijing Peoples R China

Compressive sensing (CS) based fan noise mode detection methods have been developed recently by taking advantage of the fact that the fan noise sound field is usually dominated by a limited set of modes. It has been shown that the CS based methods require remarkably few measurements and can improve mode detection capability. However, the mode sparsity would be easily destroyed either due to strong noise interference or attenuation of spinning modes. In this Paper, a nonconvex CS method based on L-1/2 minimization algorithm is proposed for fan noise azimuthal mode detection. A series of numerical simulations shows that the new L-1/2 based CS method is more robust to measurement noise and can enhance the mode sparsity under background noise interference. In the case in which the background noise level is unknown, the new L-1/2 based CS method with level correction can successfully reconstruct the mode spectrum by using an underestimated noise level. Compared to the previous convex L1 based CS method, the new L-1/2 based nonconvex CS method reduces the number of sensors and requires weaker constraints for sensor array, which is beneficial for optimal array design in practical tests. In addition, the new method can decrease the reconstruction error and improve the dynamic range. An experimental system is implemented to validate the new method. It is demonstrated that the new method can enhance the mode sparsity and improve the dynamic range by about 10 dB.

关键词： Compressive Sensing Sensors Numerical Simulation Acoustic Frequencies Blade Passing Frequency Bypass Ratio Monte Carlo Simulation iterative algorithm Aircraft Technology Numerical Modeling

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Traversing the Schrodinger Bridge Strait: Robert Fortet's Marvelous Proof Redux

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JOURNAL OF OPTIMIZATION THEORY AND APPLICATIONS 2019年第1期181卷 23-60页

作者： Essid, Montacer Pavon, Michele NYU Courant Inst Math Sci 251 Mercer St New York NY 10012 USA Univ Padua Dipartimento Matemat Tullio Levi Civita Via Trieste 63 I-35121 Padua Italy

In the early 1930s, Erwin Schrodinger, motivated by his quest for a more classical formulation of quantum mechanics, posed a large deviation problem for a cloud of independent Brownian particles. He showed that the solution to the problem could be obtained through a system of two linear equations with nonlinear coupling at the boundary (Schrodinger system). Existence and uniqueness for such a system, which represents a sort of bottleneck for the problem, was first established by Fortet in 1938/1940 under rather general assumptions by proving convergence of an ingenious but complex approximation method. It is the first proof of what are nowadays called Sinkhorn-type algorithms in the much more challenging continuous case. Schrodinger bridges are also an early example of the maximum entropy approach and have been more recently recognized as a regularization of the important optimal mass transport problem. Unfortunately, Fortet's contribution is by and large ignored in contemporary literature. This is likely due to the complexity of his approach coupled with an idiosyncratic exposition style and due to missing details and steps in the proofs. Nevertheless, Fortet's approach maintains its importance to this day as it provides the only existing algorithmic proof, in the continuous setting, under rather mild assumptions. It can be adapted, in principle, to other relevant optimal transport problems. It is the purpose of this paper to remedy this situation by rewriting the bulk of his paper with all the missing passages and in a transparent fashion so as to make it fully available to the scientific community. We consider the problem in Rd rather than in R and use as much as possible his notation to facilitate comparison.

关键词： Schrodinger system Large deviations iterative algorithm

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On an algorithm for solving Fredholm integrals of the first kind

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STATISTICS AND COMPUTING 2019年第4期29卷 645-654页

作者： Chae, Minwoo Martin, Ryan Walker, Stephen G. Case Western Reserve Univ Dept Math Appl Math & Stat Cleveland OH 44106 USA North Carolina State Univ Dept Stat Raleigh NC 27695 USA Univ Texas Austin Dept Math Austin TX 78712 USA

In this paper we use an iterative algorithm for solving Fredholm equations of the first kind. The basic algorithm and convergence properties are known under certain conditions, but we provide a simpler convergence proof without requiring the restrictive conditions that have previously been needed. Several examples of independent interest are given, including mixing density estimation and a first passage time density function involving Brownian motion. We also develop the basic algorithm to include functions which are not necessarily non-negative and, again, present illustrations.

关键词： Brownian motion first passage time Convergence Expectation-maximization iterative algorithm Mixture model

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Plasma boundary reconstruction in JET by magnetic measurements

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FUSION ENGINEERING AND DESIGN 2019年第PartB期146卷 2074-2077页

作者： Chiariello, Andrea Gaetano Formisano, Alessandro Ledda, Francesco Martone, Raffaele Murari, Andrea Pizzo, Francesco Terranova, David Univ Campania L Vanvitelli Dept Engn Aversa CE Italy Culham Sci Ctr JET Eurofus Consortium Abingdon OX14 3DB Oxon England Consorzio RFX Padua Italy

The reconstruction of the plasma boundary is a critical issue in the monitoring and control of fusion devices. The problem can be solved by the solution of force balance magneto-hydro-dynamic equations but, unfortunately, the computing burden can be not compatible with the needs of the on-line control. Advanced electromagnetic modelling of the plasma, based on surface equivalent currents recently proposed, can be a compromise between accuracy and promptness especially when a fully 3D treatment is necessary or foreseen. A procedure able to take advantage of the magnetic measurements to provide a plasma boundary reconstruction is here presented. The paper includes the illustration of a first assessment carried out on the JET by using the data of a standard axisymmetric shot, with the aim to check the coherence between the experimental evidence and the numerical procedure.

关键词： Plasma boundary Last closed magnetic surface iterative algorithm Inverse problems

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Improving energy saving of crude oil distillation units with optimal operations

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JOURNAL OF CLEANER PRODUCTION 2020年 263卷 121340-121340页

作者： Yang, Kunru Liu, Shirun He, Chang Zhang, Bingjian Chen, Qinglin Pan, Ming Sch Chem Engn & Technol Guangzhou Peoples R China Sun Yat Sen Univ Sch Mat Sci & Engn Guangzhou 510275 Peoples R China

As the most energy intensive sector in refinery industry, crude oil distillation unit can affect the overall energy consumption of a plant by up to 20%. Improving energy saving is an important factor of cleaner production and environmental impacts for crude oil distillation units. Many technologies regarding retrofit of heat exchanger network and optimal operations have been proposed to increase the energy and economic efficiencies of crude oil distillation units in the last decades. However, it is still a challenge of implementing traditional methods in practice, for instance, retrofitting are commonly restricted by process topology, safety and maintenance constraints and may lead to high capital costs because of considerable civil works;while operation models usually suffers from the computational difficulty caused by complex unit performances. To deal with the above problems, this paper presents an optimal operation strategy for improving energy efficiency of crude oil distillation units without any structural modifications. First, detailed process operations are formulated and expressed as a complex nonlinear programming model, which is then solved with a double-loop algorithm. The objective of the proposed method is to minimize process energy utilization while retain its economic benefit. This work provides an efficient tool to help engineers handily adjust process key parameters to achieve higher energy saving than the traditional approaches, especially up to 1.06 MWof energy reduction without additional retrofit investment in an industrial case. This is also equivalent to 2800 tons of CO2 emission reduction per year, and thus intensifying the overall sustainability profile of the crude oil distillation processes. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： Crude oil distillation units (CDUs) Energy saving Optimal operations Nonlinear programming iterative algorithm

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Fairness-Based Superframe Design and Resource Allocation for Dynamic Rate Adaptation in DVB-RCS2 Satellite Systems

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IEEE COMMUNICATIONS LETTERS 2019年第11期23卷 2046-2049页

作者： Jung, Dong-Hyun Shin, Min-Su Ryu, Joon-Gyu Elect & Telecommun Res Inst Satellite Technol Res Grp Daejeon 34129 South Korea

In this letter, we consider a satellite communication system, where a gateway and multiple return channel satellite terminals (RCSTs) exchange information via a satellite based on the DVB-RCS2 standard. Transmission rate adaptation is used to deal with dynamic condition of return channels from the RCSTs. A joint superframe design and resource allocation problem is formulated to maximize Jain's fairness index. To overcome the high-computational complexity to obtain the optimal solution of the problem, we decompose the joint problem into two-level hierarchical problems and propose iterative algorithms to solve them. Simulation results show that the optimal solution of two-level hierarchical problems is very close to that of the joint problem, and that the proposed algorithms have low-computational complexity at the price of reduced fairness.

关键词： Resource management Indexes Satellites Logic gates Computational complexity iterative methods Satellite communication system DVB-RCS2 superframe design resource allocation iterative algorithm

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A thermal resistance network model based on three-dimensional structure

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MEASUREMENT 2019年 133卷 439-443页

作者： Han, Lei Tong, Zhenyang Southeast Univ Key Lab MEMS Minist Educ Nanjing 210096 Jiangsu Peoples R China

A thermal resistance network model based on three-dimensional structure is proposed in this paper. In a chip package newly developed method (three-dimensional stacked package), the thermal distribution management is essential. In order to improve the thermal design of a chip package structure, a thermal resistance network model of temperature distribution is established based on the thermal resistance network and the principle of spherical wall heat conduction. The principle of spherical wall heat conduction is adopted to calculate the complete 3-D temperature distribution at arbitrary position. For the analysis of the thermal resistance of thermal convection, the convection coefficient is calculated based on iterative algorithm. When the heating power arises from 0.27 W to 2.18 W, the errors between the calculation results and the experimental results are less than 5%. The experimental results validate the calculation results well. (C) 2018 Elsevier Ltd. All rights reserved.

关键词： Thermal resistance network model Three dimension iterative algorithm Thermal distribution

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iterative algorithms for solving the split feasibility problem in Hilbert spaces

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JOURNAL OF FIXED POINT THEORY AND APPLICATIONS 2018年第1期20卷 11-11页

作者： Zhao, Jing Zong, Haili Civil Aviat Univ China Tianjin Key Lab Adv Signal Proc Tianjin 300300 Peoples R China Civil Aviat Univ China Coll Sci Tianjin 300300 Peoples R China

In this paper, we introduce two iterative algorithms for the split feasibility problem in real Hilbert spaces by reformulating it as a fixed point equation. Under suitable conditions, weak and strong convergence theorems are established. As a consequence, we obtain weak and strong convergence iterative sequences for the split equality problem introduced by Moudafi. The efficiency of the proposed algorithms is illustrated by numerical experiments. Our results improve and extend the corresponding results announced by many others.

关键词： Split feasibility problem iterative algorithm weak convergence strong convergence hilbert space

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