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Nesterov’s smoothing and Excessive Gap Methods for an Optimization Problem in VLSI Placement

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Journal of the Operations Research Society of China 2014年第4期2卷 423-443页

作者： Jian-Li Chen Yan Cui Wen-Xing Zhu Center for Discrete Mathematics and Theoretical Computer Science Fuzhou UniversityFuzhou 350108China

In this paper,we propose an algorithm for a nonsmooth convex optimization problem arising in very large-scale integrated circuit *** objective function is the sum of a large number of Half-Perimeter Wire Length(HPWL)functions and a strongly convex *** algorithm is based on Nesterov’s smoothing and excessive gap *** main advantage of the algorithm is that it can capture the HPWL information in the process of optimization,and every subproblem has an explicit solution in the process of *** convergence rate of the algorithm is Oe1=k2T;where k is the iteration counter,which is *** also present preliminary experiments on nine placement contest *** examples confirm the theoretical results.

关键词： VLSI Global placement Nonsmooth convex optimization smoothing technique Excessive gap technique

A smoothing LEVENBERG-MARQUARDT TYPE METHOD FOR LCP

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Journal of Computational Mathematics 2004年第5期22卷 735-752页

作者： Ju-liangZhang JianChen DepartmentofManagementScience SchoolofEconomicsandManagementTsinghuaUniversityBeijing100083China

In this paper, we convert the linear complementarity problem to a system of semismooth nonlinear equations by using smoothing technique. Then we use Levenberg-Marquardt type method to solve this system. Taking advantage of the new results obtained by Dan, Yamashita and Fukushima [11, 33], the global and local superlinear convergence properties of the method are obtained under very mild conditions. Especially, the algorithm is locally superlinearly convergent under the assumption of either strict complementarity or certain nonsingularity. Preliminary numerical experiments are reported to show the efficiency of the algorithm.

关键词： LCP Levenberg-Marquardt method P matrix smoothing technique Superlinear convergence

NUMERICAL TEST OF AN EARLY-SUMMER EXPLOSIVE CYCLONE EVENT IN EAST ASIA

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Acta meteorologica Sinica 2000年第3期14卷 347-360页

作者：杨福全 Isamu YAGAI Department of Atmospheric Science.Training Center of the China Meteorological Administration.Beijing 100081.China. NationalResearch Institute for Earth Science and Disaster Prevention.Science and Technology Agency.Japan.305-0006

A series of ten numerical tests are carried out using smoothing techniques in the PSU/NACR mesoscale model MM5 initial field in order to study the development reasons of a pre-summer uncommon explosive event which took place in East Asia from 1—2 *** integration fields are compared with that of original results obtained by non-smoothed initial *** results show that:(1)After the northern trough is smoothed,its corresponding cold air can not move downward and *** a weak cyclone system forms south of 25°N after 24 h integration. (2)After the southern strong moisture transportation channel is smoothed,the northem trough system can only form a weak trough along the east coast of China after 24 h integration.(3)These two separate low trough systems in the southern and northern jet systems,with strong warm moisture transportation channel and cold air respectively,are both necessary for explosive cyclone *** such an unfavorable season and location for explosive cyclone to take place,only after these two low troughs merged into a strong low vortex can the surface cyclone he developed *** the northern trough system and the southern moisture transportation channel are all indispensable for the explosive cyclone *** explosive cyclone event is the result of the interaction of northern and southern systems.

关键词： explosive cyclone smoothing technique northern trough moisture transportation channel

A New Particle Filter for Nonlinear Tracking Problems

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Chinese Journal of Aeronautics 2004年第3期17卷 170-175页

作者：李延秋沈毅刘志言 Dept. of Control Science and Engineering Harbin Institute of TechnologyHarbin 150001 China

A new particle filter is presented for nonlinear tracking problems. Inpractice, maneuvering target-tracking systems are usually nonlinear and incompletely observed, andthe main difficulty of maneuvering target-tracking problem lies in the fact that the maneuverabilityat every step is of high uncertainties. Here a new smoothing particle filter algorithm is proposed,which combines the particle filter to tackle the non-linear and non-Gaussian peculiarities of theproblem, together with smoothing of the PDF of system modes and thus settles the estimate problem ofthe target maneuverability. The simulation comparison with the auxiliary particle filters showsthat the approach has superiority and yields performance improvements in solving nonlinear trackingproblems.

关键词： particle filters nonlinear/non-Gaussian model maneuvering target tracking smoothing technique

Tone model integration based on discriminative weight training for Putonghua speech recognition

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Chinese Journal of Acoustics 2008年第3期27卷 193-202页

作者： HUANG Hao ZHU Jie Department of Electronic Engineering Shanghai Jiaotong University Shanghai 200240

A discriminative framework of tone model integration in continuous speech recognition was proposed. The method uses model dependent weights to scale probabilities of the hidden Markov models based on spectral features and tone models based on tonal features. The weights are discriminatively trained by minimum phone error criterion. Update equation of the model weights based on extended Baum-Welch algorithm is derived. Various schemes of model weight combination are evaluated and a smoothing technique is introduced to make training robust to over fitting. The proposed method is ewluated on tonal syllable output and character output speech recognition tasks. The experimental results show the proposed method has obtained 9.5% and 4.7% relative error reduction than global weight on the two tasks due to a better interpolation of the given models. This proves the effectiveness of discriminative trained model weights for tone model integration.

关键词： continuous speech recognition model integration hidden Markov models smoothing technique error reduction

A Semi-Lagrangian Type Solver for Two-Dimensional Quasi-Geostrophic Model on a Sphere

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Applied Mathematics 2016年第18期7卷 2296-2306页

作者： Quanyong Zhu Yan Yang Department of Mathematics Lishui University Lishui China Jiangsu Key Laboratory for NSLSCS School of Mathematical Sciences Nanjing Normal University Nanjing China

In this paper, we propose a numerical method based on semi-Lagrangian approach for solving quasi-geostrophic (QG) equations on a sphere. Using potential vorticity and stream-function as prognostic variables, two-order centered difference is suggested on the latitude-longitude grid. In our proposed numerical scheme, advection terms are expressed in a Lagrangian frame of reference to circumvent the CFL restriction. The pole singularity associated with the latitude-longitude grid is eliminated by a smoothing technique for the initial flow. Error analysis is provided for the numerical scheme.

关键词： Quasi-Geostrophic Equations Semi-Lagrangian Methods smoothing technique Error Analysis Pole Singularity