检索结果-南通市图书馆

Proximal Methods with Bregman Distances to Solve VIP on Hadamard Manifolds with Null Sectional Curvature

在线全文

学校读者我要写书评

暂无评论

Journal of the Operations Research Society of China 2021年第3期9卷 499-523页

作者： Erik Alex Papa Quiroz paulo Roberto Oliveira Universidad Nacional Mayor de San Marcos Universidad Privada del NorteLimaPeru PESC-COPPE Federal University of Rio de JaneiroRio de Janeiro CEP 21941-972Brazil

We present an extension of the proximal point method with Bregman distances to solve variational inequality problems(VIP)on Hadamard manifolds with null sectional *** some natural assumptions,as for example,the existence of solutions of the VIP and the monotonicity of the multivalued vector field,we prove that the sequence of the iterates given by the method converges to a solution of the ***,this convergence is linear or superlinear with respect to the Bregman distance.

关键词： Proximal point methods Hadamard manifolds Bregman distances Variational inequality problems Monotone vector field

Chaos Suppression in a Sine Square Map through Nonlinear Coupling

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2011年第11期28卷 45-48页

作者： Eduardo L.Brugnago paulo C.Rech Departamento de Física Universidade do Estado de Santa Catarina89223-100 JoinvilleBrazil

We study a pair of nonlinearly coupled identical chaotic sine square *** specifically,we investigate the chaos suppression associated with the variation of two ***-dimensional parameter-space regions where the chaotic dynamics of the individual chaotic sine square map is driven towards regular dynamics are ***,the dynamics of the coupled system is numerically characterized as the parameters are changed.

关键词： chaotic dynamics Chaos

TLBO with variable weights applied to shop scheduling problems

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

CAAI Transactions on Intelligence Technology 2019年第3期4卷 148-158页

作者： Leonardo Ramos Rodrigues Joao paulo Pordeus Gomes Electronics Division Institute of Aeronautics and SpacePraca Marechal Eduardo Gomes50Sao Josedos Campos 12228-904Brazil Computer Science Department Federal University of CearaRua Campus do PiciSnFortaleza 60440-554Brazil

The teaching–learning-based optimisation (TLBO) algorithm is a population-based metaheuristic inspired on the teaching–learning process observed in a classroom. It has been successfully used in a wide range of applications. In this study, the authors present a variant version of TLBO. In the proposed version, different weights are assigned to students during the student phase, with higher weights being assigned to students with better solutions. Three different approaches to assign weights are investigated. Numerical experiments with benchmark instances of the flow-shop and the job-shop scheduling problems are carried out to investigate the performance of the proposed approaches. They compare the proposed approaches with the original TLBO algorithm and with two variants of TLBOs proposed in the literature in terms of solution quality, convergence speed and simulation time. The results obtained by the application of a Friedman statistical test showed that the proposed approaches outperformed the original version of TLBO in terms of convergence, with no significant losses in the average makespan. The additional simulation time required by the proposed approaches is small. The best performance was achieved with the approach of assigning a fixed weight to half the students with the best solutions and assigning zero to other students.

关键词： TLBO variable weights shop scheduling problems

3D Progressive Damage Based Macro-Mechanical FE Simulation of Machining Unidirectional FRP Composite

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2018年第3期31卷 128-143页

作者： Yan-Li He Joao-paulo Davim Hong-Qian Xue Key Laboratory of Contemporary Design and Integrated Manufacturing Technology of Ministry of Education School of Mechanical EngineeringNorthwestern Polytechnical University Department of Mechanical Engineering University of AveiroCampus Santiago

Finite element(FE) simulation is a powerful tool for investigating the mechanism of machining fiber?reinforced polymer composite(FRP). However in existing FE machining simulation works,the two?dimensional(2 D) progressive damage models only describe material behavior in plane stress,while the three?dimensional(3 D) damage models always assume an instantaneous sti ness reduction pattern. So the chip formation mechanism of FRP under machin?ing is not fully analyzed in general stress state. A 3 D macro?mechanical based FE simulation model was developed for the machining of unidirectional glass fiber reinforced plastic. An energy based 3 D progressive damage model was proposed for damage evolution and continuous sti ness degradation. The damage model was implemented for the Hashin?type criterion and Maximum stress criterion. The influences of the failure criterion and fracture energy dissipa?tion on the simulation results were studied. The simulated chip shapes,cutting forces and sub?surface damages were verified by those obtained in the reference experiment. The simulation results also show consistency with previous 2 D FE models in the reference. The proposed research provides a model for simulating FRP material behavior and the machining process in 3 D stress state.

关键词： FRP Macro mechanical Machining Finite element Progressive damage

Changes in the Dynamics of a Rössler Oscillator by an External Forcing

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2013年第3期30卷 22-25页

作者： Amanda C.Mathias paulo C.Rech Departamento de Física Universidade do Estado de Santa Catarina89219-710 JoinvilleBrazil

We report some results indicating changes in the observed dynamics of the Rössler model under the influence of external sinusoidal *** varying the control parameters of the external sinusoidal forcing,namely the amplitude and the angular frequency,we show,through numerical simulations which include parameter planes and Lyapunov exponents,that the external forcing can produce both chaos-order and order-chaos *** also show that the sinusoidal forcing may generate hyperchaos.

关键词： chaos sinusoidal transitions

A Parameter-Space Analysis of the Rikitake System

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2013年第12期30卷 13-16页

作者： Rodrigo A.da Silva paulo C.Rech Departamento de Física Universidade do Estado de Santa Catarina89219-710 JoinvilleBrazil

We investigate analytically and numerically the dynamics of the Rikitake *** Routh–Hurwitz criterion is used to study the stability of the equilibrium points of the differential equation system model,as functions of two *** dynamics of the model are numerically studied using diagrams that associate colors to the largest Lyapunov exponent value,in two-dimensional parameter ***,phase-space plots and bifurcation diagrams are used to distinguish periodic and chaotic attractors.

关键词： bifurcation exponent chaotic

Nutrient content affecting Spodoptera frugiperda and Dalbulus maidis occurrence in corn

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Insect Science 2007年第2期14卷 117-123页

作者： CRISTINA SCHETINO BASTOS JOAO CARLOS CARDOSO GALVAO MARCELO COUTINHO PICANCO paulo ROBERTO GOMES PEREIRA paulo ROBERTO CECON EMBRAPA/Algodao Centenário Campina Grande PB Brazil Departamento de Fitotecnia Universidade Federal de Vicosa (UFV) Vicosa MG Brazil. Departamento de Biologia Animal Universidade Federal de Vicosa (UFV) Vicosa MG Brazil. Departamento de Informática Campus Universitário Universidade Federal de Vicosa (UFV) Vicosa MG Brazil.

This work aims to study the effect of the nutrient contents in the leaves of corn on the incidence of Spodopterafrugiperda （Smith）（Lepidoptera： Noctuidae） and Dalbulus maidis （Delong ＆ Wolcott）（Homoptera： Cicadellidae）. The treatments were represented by unfertilized corn plants and corn plants fertilized with 250 kg of the formulation 4-14-8 （N- P-K）＋ 100 kg of ammonium sulfate （AS）/ha and 500 kg of the formulation 4-14-8 （N-P-K）＋200 kg of AS/ha, arranged in randomized blocks with four replicates. Attacks by S. frugiperda and D. maidis were higher as the nitrogen, sulfur, calcium and copper content in the leaves of corn increased. The effects of calcium and copper found in this study were not consistent with that of lower susceptibility associated with higher levels of these nutrients mentioned in the literature. We believe that there was a cumulative effect of the nutrients altogether, building up a nutritiously better vegetable which in turn had less reserve for defense, or that the content of both nutrients in the leaves were not high enough to induce such effects.

关键词： calcium copper corn cicada fall armyworm fertilization nitrogen sulfur

Laparoscopic resection for hepatocellular carcinoma: eastern and western experiences

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Cancer Research 2014年第3期26卷 234-236页

作者： paulo Herman Fabricio Ferreira Coelho Liver Surgery Unit Department of GastroenterologyUniversity of Sao Paulo Medical School

Hepatocellular carcinoma （HCC） is the most common primary liver cancer （1）. The incidence is rising in the last decades due to many factors, especially hepatitis C, alcoholic liver disease and non-alcoholic steatohepatitis. Moreover, the introduction of screening programs in patients with chronic liver disease has led to an increase in HCC diagnosis （1,2）. In the western world, 80% to 90% of HCC eases occur in patients with liver cirrhosis （3） while this proportion is lower in some regions in Asia and sub-Saharian Africa, where hepatitis B remains as an important etiologic factor for chronic liver disease （2,4）. In 1990, the annual world frequency of HCC was 437,000 cases/year （1）, and in 2012 the number reached 782,200 cases/year being responsible for 746,000 deaths （5）. Nowadays, HCC represents the 6th most frequent neoplastic disease in the world and the 3rd in mortality （5）.

关键词： HCC eastern and western experiences Laparoscopic resection for hepatocellular carcinoma

Tree structure and diversity of lowland Atlantic forest fragments：comparison of disturbed and undisturbed remnants

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2016年第3期27卷 605-609页

作者： Fabricio Alvim Carvalho Joao Marcelo Alvarenga Braga Marcelo Trindade nascimento Departamento de Botanica Universidade Federal de Juiz de Fora. Campus Universitario s/n Sao PedroJuiz de Fora-MG 36036-900 Brazil Instituto de Pesquisas do Jardim Botanico do Rio de Janeiro. Rio de Janeiro-RJ Brazil Laboratorio de Ciencias Ambientais CBB Universidade Estadual do Norte Fluminense Campos dos Goytacazes-RJ 28013-602 Brazil

This study describes the tree community structure of three moist lowland Atlantic Forest fragments in Rio de Janeiro State, southeastern Brazil. Two fragments were disturbed and an undisturbed one was used as reference. Our hypothesis was that disturbed fragments show distinct structural patterns in comparison with undisturbed stands due to past disturbance practices and forest fragmentation. Four 100 ×5 m sampling plots were demarcated in each fragment and all live and dead trees with DBH C 5 cm were located, measured and identified. The results supported our hypothesis, due to the high values found for standing dead trees, an increase of dominance of a few pioneer species, lower values of large trees and species richness in disturbed fragments in comparison with the undisturbed one. The advanced fragmentation process in the Southern Brazilian lowland areas and the high species richness in undisturbed areas highlight these forest fragments as priority areas for conservation and management.

关键词： Phytosociology Tree community Forestfragmentation . Hotspot Brazil