期刊文献+
共找到34篇文章
< 1 2 >
每页显示 20 50 100
Modeling of Ship Maneuvering Motion Using Neural Networks 被引量:13
1
作者 Weilin Luo Zhicheng Zhang 《Journal of Marine Science and Application》 CSCD 2016年第4期426-432,共7页
In this paper, Neural Networks (NNs) are used in the modeling of ship maneuvering motion. A nonlinear response model and a linear hydrodynamic model of ship maneuvering motion are also investigated. The maneuverabil... In this paper, Neural Networks (NNs) are used in the modeling of ship maneuvering motion. A nonlinear response model and a linear hydrodynamic model of ship maneuvering motion are also investigated. The maneuverability indices and linear non-dimensional hydrodynamic derivatives in the models are identified by using two-layer feed forward NNs. The stability of parametric estimation is confirmed. Then, the ship maneuvering motion is predicted based on the obtained models. A comparison between the predicted results and the model test results demonstrates the validity of the proposed modeling method. 展开更多
关键词 ship maneuvering response models mathematical modeling group model system identification neural networks
在线阅读 下载PDF
Mechanism of local scour around submarine pipelines based on numerical simulation of turbulence model 被引量:5
2
作者 LUE Lin LI Yucheng CHEN Bing 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2006年第2期142-152,共11页
The mechanism of local scour around submarine pipelines is studied numerically based on a renormalized group (RNG) turbulence model. To validate the numerical model, the equilibrium profiles of local scour for two c... The mechanism of local scour around submarine pipelines is studied numerically based on a renormalized group (RNG) turbulence model. To validate the numerical model, the equilibrium profiles of local scour for two cases are simulated and compared with the experimental data. It shows that the RNG turbulence model can give an appropriate prediction for the configuration of equilibrium scour hole, and it is applicable to this situation. The local scour mechanism around submarine pipelines including the flow structure, shear stress distribution and pressure field is then analyzed and compared with experiments. For further comparison and validation, especially for the flow structure, a numerical calculation employing the large eddy simulation (LES) is also conducted. The numerical results of RNG demonstrate that the critical factor governing the equilibrium profile is the seabed shear stress distribution in the case of bed load sediment transport, and the two-equation RNG turbulence model coupled with the law of wall is capable of giving a satisfying estimation for the bed shear stress. Moreover, the piping phenomena due to the great difference of pressure between the upstream and downstream parts of pipelines and the vortex structure around submarine pipelines are also simulated successfully, which are believed to be the important factor that lead to the onset of local scour. 展开更多
关键词 submarine pipeline mechanism of local scour renormalized group turbulence model large eddy simulation PIPING
在线阅读 下载PDF
A P2P Reference Model 被引量:1
3
作者 YANG Dengqi CHEN Xingshu WANG Jian 《China Communications》 SCIE CSCD 2010年第4期96-102,共7页
P2P is a complex system.Many researches on P2P architecture have been done.These researches have provided valuable references for the standardization of P2P technology.However,the standardization can not be achieved b... P2P is a complex system.Many researches on P2P architecture have been done.These researches have provided valuable references for the standardization of P2P technology.However,the standardization can not be achieved because there are still some problems in existing studies.This paper proposes a 5-layer reference model which clearly defines the functionalities of each layer,and distinctly describes the interface and the relationship between layers.This model is able to clearly show the internal structure of P2P system and the working process of data flow in P2P system.Validation shows that this model is general and rational. 展开更多
关键词 Peer to Peer Reference model Shared Group Dynamic modeling Uniform Scheduling STANDARDIZATION
在线阅读 下载PDF
Group Decision-Making Model of Renal Cancer Surgery Options Using Entropy Fuzzy Element Aczel-Alsina Weighted Aggregation Operators under the Environment of Fuzzy Multi-Sets 被引量:1
4
作者 Jing Fu Jun Ye Liping Xie 《Computer Modeling in Engineering & Sciences》 SCIE EI 2022年第3期1751-1769,共19页
Since existing selection methods of surgical treatment schemes of renal cancer patients mainly depend on physicians’clinical experience and judgments,the surgical treatment options of renal cancer patients lack their... Since existing selection methods of surgical treatment schemes of renal cancer patients mainly depend on physicians’clinical experience and judgments,the surgical treatment options of renal cancer patients lack their scientifical and reasonable information expression and group decision-making model for renal cancer patients.Fuzzy multi-sets(FMSs)have a number of properties,which make them suitable for expressing the uncertain information of medical diagnoses and treatments in group decision-making(GDM)problems.To choose the most appropriate surgical treatment scheme for a patient with localized renal cell carcinoma(RCC)(T1 stage kidney tumor),this article needs to develop an effective GDM model based on the fuzzy multivalued evaluation information of the renal cancer patients.First,we propose a conversionmethod of transforming FMSs into entropy fuzzy sets(EFSs)based on the mean and Shannon entropy of a fuzzy sequence in FMS to reasonably simplify the information expression and operations of FMSs and define the score function of an entropy fuzzy element(EFE)for ranking EFEs.Second,we present the Aczel-Alsina t-norm and t-conorm operations of EFEs and the EFE Aczel-Alsina weighted arithmetic averaging(EFEAAWAA)and EFE Aczel-Alsina weighted geometric averaging(EFEAAWGA)operators.Third,we develop a multicriteria GDM model of renal cancer surgery options in the setting of FMSs.Finally,the proposed GDM model is applied to two clinical cases of renal cancer patients to choose the best surgical treatment scheme for a renal cancer patient in the setting of FMSs.The selected results of two clinical cases verify the efficiency and rationality of the proposed GDM model in the setting of FMSs. 展开更多
关键词 Fuzzy multi-set entropy fuzzy element entropy fuzzy element Aczel-Alsina weighted arithmetic averaging operator entropy fuzzy element Aczel-Alsina weighted geometric averaging operator renal cancer surgical treatment option group decision-making model
在线阅读 下载PDF
SU(3) Simple Group Model and New Z' Properties in Future Linear Colliders
5
作者 LIU Yao-Bei WANG Shuai-Wei ZHANG Wen-Qing 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第2期299-304,共6页
In the SU(3) simple group model, the new neutral gauge boson Z' couples to pairs of SM fermions with couplings fixed in terms of the SM gauge couplings and depending only on the choice of the fermion embedding. In ... In the SU(3) simple group model, the new neutral gauge boson Z' couples to pairs of SM fermions with couplings fixed in terms of the SM gauge couplings and depending only on the choice of the fermion embedding. In this paper, we calculate the contributions of this new particle to the processes e^+e^-→l^+l^-, bb^-, and cc^- and study the possibility of detecting this new particle via these processes in the future high-energy linear e^+e^- collider(LC) experiments with √s= 500 GeV and £int= 340 fb^-1. We find that the new gauge boson Z' is most sensitive to the process e^+e^-→b^+b^-. As long as Mz,≤2 TeV , the absolute values of the relative correction parameter are larger than 5%. We calculate the forward-backward asymmetries and left-right asymmetries for the process e^+e^-→c^+c^-, with both the universal and anomaly-free fermion embeddings. Bounds on Z' masses are also estimated within 95% confidence level. 展开更多
关键词 SU(3) simple group model relative corrections forward-backward asymmetry left-right asymme-try new gauge boson
在线阅读 下载PDF
The Game Model Analysis between the Individual and the Group
6
作者 Dehai Liu Dagang Wang Shulin Liu 《Chinese Business Review》 2004年第2期29-32,共4页
This paper analyses the game model between the individual and the group that has the characteristics of Stackelberg model in traditional game theory and replicator dynamic model in evolutionary game theory. In the fir... This paper analyses the game model between the individual and the group that has the characteristics of Stackelberg model in traditional game theory and replicator dynamic model in evolutionary game theory. In the first phase of game, the bounded rationality group players adopt the replicator dynamic behavior. Secondly, the full rationality individual player decides the own response function by the strategies distribution of group players. The shortsighted individual player will take the risk-dominant strategy. This model has some unique characteristics. 展开更多
关键词 the individual and the group Stackelberg model replicator dynamic group decision-making
在线阅读 下载PDF
Study on Agency Models within Internal Capital Market of Enterprise Group
7
作者 Xudong Lin Li Li Qin You 《Chinese Business Review》 2003年第5期62-69,共8页
In order to overcome the shortcomings brought up by the single-layer agency relation analyses of agency problems within enterprise group, two-tiered agency models in the internal capital market are set up, and how ren... In order to overcome the shortcomings brought up by the single-layer agency relation analyses of agency problems within enterprise group, two-tiered agency models in the internal capital market are set up, and how rent-seeking behaviors of member firms' managers affect investment allocation decision made by headquarters manager is demonstrated. From equilibrium solutions of the model, it's inferred that the larger the divergence of member firm's productivity is, the higher probability of investment allocation distortion is. 展开更多
关键词 enterprise group internal capital market two-tiered agency models
在线阅读 下载PDF
Public-Key Function-Private Inner-Product Predicate Encryption from Pairings
8
作者 WAN Ming WANG Geng GU Da-Wu 《密码学报(中英文)》 北大核心 2025年第1期227-246,共20页
This study constructs a function-private inner-product predicate encryption(FP-IPPE)and achieves standard enhanced function privacy.The enhanced function privacy guarantees that a predicate secret key skf reveals noth... This study constructs a function-private inner-product predicate encryption(FP-IPPE)and achieves standard enhanced function privacy.The enhanced function privacy guarantees that a predicate secret key skf reveals nothing about the predicate f,as long as f is drawn from an evasive distribution with sufficient entropy.The proposed scheme extends the group-based public-key function-private predicate encryption(FP-PE)for“small superset predicates”proposed by Bartusek et al.(Asiacrypt 19),to the setting of inner-product predicates.This is the first construction of public-key FP-PE with enhanced function privacy security beyond the equality predicates,which is previously proposed by Boneh et al.(CRYPTO 13).The proposed construction relies on bilinear groups,and the security is proved in the generic bilinear group model. 展开更多
关键词 predicate encryption function privacy inner product generic group model
在线阅读 下载PDF
C系列螺旋桨图谱在舰船运动仿真中的应用
9
作者 王在高 徐东星 《集美大学学报(自然科学版)》 CAS 2020年第6期437-440,共4页
为探索C系列螺旋桨图谱在舰船运动仿真中的应用,提升变螺距螺旋桨舰船运动仿真效果,采用傅里叶级数拟合螺旋桨图谱,改进推力和扭矩系数的螺旋桨推力模型,建立变螺距螺旋桨船舶三自由度运动数学模型。对一艘变螺距船舶进行运动仿真。仿... 为探索C系列螺旋桨图谱在舰船运动仿真中的应用,提升变螺距螺旋桨舰船运动仿真效果,采用傅里叶级数拟合螺旋桨图谱,改进推力和扭矩系数的螺旋桨推力模型,建立变螺距螺旋桨船舶三自由度运动数学模型。对一艘变螺距船舶进行运动仿真。仿真结果表明,C系列螺旋桨拟合图谱与原图谱吻合度良好。仿真结果与实船试验数据进行比对,误差较小。 展开更多
关键词 C系列螺旋桨图谱 舰船运动仿真 傅里叶级数拟合 MMG(mathematical model group)模型
在线阅读 下载PDF
Numerical Simulation and Experimental Study of the Effects of Disposal Space on the Flow Field Around the Combined Three-Tube Reefs 被引量:6
10
作者 郑延璇 梁振林 +5 位作者 关长涛 宋协法 李娇 崔勇 李强 周游 《China Ocean Engineering》 SCIE EI CSCD 2015年第3期445-458,共14页
The artificial reefs placed on the seabed with different layouts and disposal spaces will produce variational flow field. The intensity and scale of the combined three-tube artificial reefs with different layouts at f... The artificial reefs placed on the seabed with different layouts and disposal spaces will produce variational flow field. The intensity and scale of the combined three-tube artificial reefs with different layouts at five Reynolds numbers(Re) are numerically investigated by use of the RNG k-ε turbulent model and SIMPLEC algorithm. A stationary no-slip boundary condition is used on the models and the bottoms, and the free surface is treated as a "moving wall" with zero shear force and the same velocity with inflow. In order to validate the simulation results, a particle image velocimetry(PIV) experiment is carried out to analyze the flow field. The numerical simulation results are consistent with the data obtained from experiment. The corresponding errors are all below 20%. Based on the validation, the effects of disposal space on flow field are simulated and analyzed. According to the simulation, in a parallel combination, a better artificial reef effect is obtained when the disposal space between two parallel reefs is 1.0L(L is the length of the combined three-tube reef model). In a vertical combination, when the disposal space between two vertical reefs is 1.0L to 2.0L, the artificial reef effect is better. 展开更多
关键词 artificial reef model hydrodynamic forces flow field renormalization group k–ε turbulent model
在线阅读 下载PDF
Investigation on Maneuverability of a Twin-Screw Ship Driven by One Screw 被引量:1
11
作者 刘小健 范佘明 《Journal of Shanghai Jiaotong university(Science)》 EI 2017年第4期434-439,共6页
It is possible for a twin-screw ship that one screw failure occurs during navigation, and the maneuverability in this case should be noticed by ship designers and operators. It is of great significance to evaluate the... It is possible for a twin-screw ship that one screw failure occurs during navigation, and the maneuverability in this case should be noticed by ship designers and operators. It is of great significance to evaluate the related risk. Firstly, a mathematical model for the twin-screw ship maneuvering motion with one failed screw is developed based on the maneuvering model group (MMG) equations, and verified by the model test results. Secondly, the maneuvering motions of a twin-screw liquefied natural gas (LNG) ship with one free rotating failure screw or with one locked failure screw are simulated and compared by using the mathematical model. It is shown that the numerical modeling results are in agreement with the model test results. Compared with those of normal navigation, the port turning ability of the ship with one failed port screw is better, but the starboard turning ability and yaw checking ability become worse. The maneuverability of the ship with locked failure screw is better than that with free failure screw, although the ship speed drops obviously. © 2017, Shanghai Jiaotong University and Springer-Verlag GmbH Germany. 展开更多
关键词 twin-screw ship screw failure MANEUVERABILITY maneuvering model group(MMG) equation
原文传递
Dynamic Analysis for the Global Performance of An SPM-Feeder-Cage System Under Waves and Currents 被引量:2
12
作者 Cristian CIFUENTES M.H.KIM 《China Ocean Engineering》 SCIE EI CSCD 2015年第3期415-430,共16页
In the present study, the dynamic response of a coupled SPM-feeder-cage system under irregular waves and shear currents is analyzed. A numerical model is developed by using the commercial software Orca Flex. Hydrodyna... In the present study, the dynamic response of a coupled SPM-feeder-cage system under irregular waves and shear currents is analyzed. A numerical model is developed by using the commercial software Orca Flex. Hydrodynamics coefficients of the vessel are calculated by using a 3D diffraction/radiation panel program. First- and second-order wave forces are included in the calculations. Morison equation is used to compute the drag force on line elements representing the net. Drag coefficients are determined at every time step in the simulation considering the relative normal velocity between the structural elements and the fluid flow. The dynamic response of the coupled system is analyzed for various environments and net materials. The results of the study show the effects of solidity ratio of the net and vertical positions of the cage on the overall dynamic response of the system, confirming the viability of this type of configuration for future development of offshore aquaculture in deep waters. 展开更多
关键词 offshore aquaculture SPM(single point mooring) feeder vessel connecting lines operational/survival environment drag force equivalent net cage grouping net modeling line tensions solidity ratio
在线阅读 下载PDF
INFLUENCES OF CASTING SPEED AND SEN DEPTH ON FLUID FLOW IN THE FUNNEL TYPE MOLD OF A THIN SLAB CASTER 被引量:1
13
作者 B.W. Li X.Y. Tian E.G. Wang J.C. He 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2007年第1期15-26,共12页
In recent years, thin slab continuous casting technology has been widely used to improve the quality of the product and to reduce the cost. One of the challenges faced by this technology is to design reasonable flow p... In recent years, thin slab continuous casting technology has been widely used to improve the quality of the product and to reduce the cost. One of the challenges faced by this technology is to design reasonable flow patterns, which strongly affect the surface and inner properties of the final slab in the mold. With the fixed scales and complex geometrical structures of nozzle and funnel type mold, a series of numerical simulations are made to analyze the flow patterns in melt steel using finite volume method based on structured body fitted coordinate grids. The CFD (computational fluid dynamics) package is validated first using one typical case described in previously published studies, and then it is developed to study the effect of operational parameters on fluid flow in thin slab caster. Two operational parameters, casting speed and SEN (submerged entry nozzle) depth, are mainly considered for numerical analysis. On the basis of present simulations, the reasonable SEN submergence depths corresponding to different casting speeds are suggested according to fluid flow characteristics like, flow jet impingement on the narrow side of the mold, flow speed of the melt steel beneath the meniscus and the recirculation region. This is the first stage of study on the numerical analysis of the whole thin slab casting process with electromagnetic brake. 展开更多
关键词 continuous casting thin slab submerged entry nozzle (SEN) numerical analysis funnel type mold standard k-ε model RNG (renormalization group) k-ε model
在线阅读 下载PDF
Chiral Symmetry Breaking for Fermions Charged under Large Lie Groups
14
作者 Felipe J.Llanes-Estrada Alexandre Salas-Bernardez 《Communications in Theoretical Physics》 SCIE CAS CSCD 2019年第4期410-416,共7页
We reexamine the dynamical generation of mass for fermions charged under various Lie groups with equal charge and mass at a high Grand Uni?cation scale, extending the Renormalization Group Equations in the perturbativ... We reexamine the dynamical generation of mass for fermions charged under various Lie groups with equal charge and mass at a high Grand Uni?cation scale, extending the Renormalization Group Equations in the perturbative regime to two loops and matching to the Dyson-Schwinger Equations in the strong coupling regime. 展开更多
关键词 standard model group running fermion mass grand unification scale
原文传递
Stability and stabilization of discrete T-S fuzzy time-delay system based on maximal overlapped-rules group 被引量:2
15
作者 Songtao Zhang Xiaowei Zhao Jiantong Zhang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2016年第1期201-210,共10页
The problems of stability and stabilization for the discrete Takagi-Sugeno(T-S) fuzzy time-delay system are investigated.By constructing a discrete piecewise Lyapunov-Krasovskii function(PLKF) in each maximal over... The problems of stability and stabilization for the discrete Takagi-Sugeno(T-S) fuzzy time-delay system are investigated.By constructing a discrete piecewise Lyapunov-Krasovskii function(PLKF) in each maximal overlapped-rules group(MORG),a new sufficient stability condition for the open-loop discrete T-S fuzzy time-delay system is proposed and proved.Then the systematic design of the fuzzy controller is investigated via the parallel distributed compensation control scheme,and a new stabilization condition for the closed-loop discrete T-S fuzzy time-delay system is proposed.The above two sufficient conditions only require finding common matrices in each MORG.Compared with the common Lyapunov-Krasovskii function(CLKF) approach and the fuzzy Lyapunov-Krasovskii function(FLKF) approach,these proposed sufficient conditions can not only overcome the defect of finding common matrices in the whole feasible region but also largely reduce the number of linear matrix inequalities to be solved.Finally,simulation examples show that the proposed PLKF approach is effective. 展开更多
关键词 stability analysis maximal overlapped-rules group(MORG) Takagi-Sugeno(T-S)fuzzy model discrete time-delay system piecewise Lyapunov-Krasovskii function(PLKF).
在线阅读 下载PDF
Nymphaeaceae Salisb. and Trapaceae Dumort. Families in the Collection of O.V. Fomina Botanical Garden
16
作者 Tatyana Mazur Nikolai Didukh Anna Didukh 《Journal of Life Sciences》 2012年第1期114-118,共5页
On basis of aquatic and riverside-aquatic plants collection of O.V. fomina botanical garden is conducted research of ontogenesis, ecology, phenology, carpogenesis, biomorphology, life forms, adaptatations, of this gr... On basis of aquatic and riverside-aquatic plants collection of O.V. fomina botanical garden is conducted research of ontogenesis, ecology, phenology, carpogenesis, biomorphology, life forms, adaptatations, of this group's plants, peculiarities of their cultivation and application in conditions of temperate zone of Ukraine. Special values in research have ancient genera and species, which include representatives ofNymphaeaceae salisb, and trapaceae Dumort. families, 22 species, 6 varieties, 1 hybrid, 30 cultivars of which are presented in collection of garden in open and covered soil. For the first time in covered soil of two conservatories ecological modeling was conducted. Placement of plants is done in form of 5 models of artificial ecotopes, in 155 abatises. Four ecobiomorphological groups based on rhizome system were determined for Nymphaeaceae, among which conditionally-rhizome and conditionally-stolone are provided for the first time. 展开更多
关键词 Aquatic and riverside-aquatic plants ancient genera NYMPHAEACEAE trapaceae models of artificial ecotopes ecobiomorphological groups ontogenesis.
在线阅读 下载PDF
Analysis of influencing factors and establishing predictive model of mucosal healing under endoscopy in Crohn's disease
17
作者 LI Tiange 《China Medical Abstracts(Internal Medicine)》 2025年第3期172-173,共2页
Objective To investigate the influencing factors of mucosal healing under endoscopy in patients with Crohn's disease (CD) and to establish a predictive model.Methods From January 1,2023 to August 31,2024,124 patie... Objective To investigate the influencing factors of mucosal healing under endoscopy in patients with Crohn's disease (CD) and to establish a predictive model.Methods From January 1,2023 to August 31,2024,124 patients with CD were hospitalized at the Department of Gastroenterology,Renmin Hospital of Wuhan University were retrospectively enrolled as the modeling group. 展开更多
关键词 influencing factors modeling group mucosal healing crohns disease mucosal healing endoscopy investigate influencing factors establish predictive modelmethods ENDOSCOPY
原文传递
SU(3) simple group model and single top production at the e^-γ colliders
18
作者 刘要北 王学雷 +1 位作者 任晓燕 曹永华 《Chinese Physics C》 SCIE CAS CSCD 北大核心 2008年第2期88-91,共4页
In the framework of the SU(3) simple group model, we consider the single top quark production process e^-γ →vebt^-. We find that the correction effects on the process mainly come from the terms of the tree-level ... In the framework of the SU(3) simple group model, we consider the single top quark production process e^-γ →vebt^-. We find that the correction effects on the process mainly come from the terms of the tree-level Wqq' couplings. In the reasonable parameter space of the SU(3) simple group model, the deviation of the total production cross section σ^tot from its SM value is larger than 5%, which might be detected in the future high energy linear e^+e^- collider (LC) experiments. 展开更多
关键词 SU(3) simple group model free parameter cross section
原文传递
Prediction of Liquid-Liquid Equilibrium Using the Group Solubility Parameter Model
19
作者 赵沫 陈福明 《Tsinghua Science and Technology》 SCIE EI CAS 2005年第5期561-566,共6页
The group solubility parameter (GSP) model was used to analyze the liquid-liquid equilibrium (LLE) of ternary and quaternary systems. The GSP parameters are divided into four dimensions representing the four major... The group solubility parameter (GSP) model was used to analyze the liquid-liquid equilibrium (LLE) of ternary and quaternary systems. The GSP parameters are divided into four dimensions representing the four major intermolecular forces. The values of the parameters were determined by regression using the nonlinear SIMPLEX optimization method to fit the LLE data of 548 ternary and 26 quaternary systems selected from the literature. LLE predictions of 8 ternary systems were then made using the fit parameters. Comparison of the results with predictions using the modified UNIFAC model shows that the GSP model has less adjustable parameters to achieve a similar accuracy and that the parameter values are easily acquired by analysis of available data. 展开更多
关键词 group solubility parameter group contribution model liquid-liquid equilibrium activity coefficient
原文传递
上一页 1 2 下一页 到第
使用帮助 返回顶部