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Classification of plant functional types based on the nutrition traits: a case study on alpine meadow community in the Zoigê Plateau 被引量:6
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作者 SHEN Song-tao ZHANG Shu-jie +1 位作者 FAN Min WANG Qing 《Journal of Mountain Science》 SCIE CSCD 2017年第10期2003-2012,共10页
The ecological concept of Plant Functional Types(PFTs), which refers to the assemblage of plants with certain functional traits, has been introduced for the study of plant responses to the environment change and hum... The ecological concept of Plant Functional Types(PFTs), which refers to the assemblage of plants with certain functional traits, has been introduced for the study of plant responses to the environment change and human disturbance. Taking the alpine meadow community in the Zoigê Plateau as a study case, this paper classified PFTs in terms of plant nutrition traits. The sequential results are as follows.(1) The main herbages in the Zoigê Plateau included 16 species in 5 families. Among the five families, Cyperaceae vegetation accounted for 81.37%of herbage area in total, while the remaining 4families occupied less than 20%. As for the species,Kobresia setchwanensis Hand.-Maizz. was dominant,accounting for 48.74% of the total area; while the remaining 51.26% was comprised of Polygonum viviparum L., Anaphalis fiavescens Hand.-Mazz.,Stipa aliena Keng and other species.(2) By using the Principal Component Analysis(PCA), the assessment of herbages nutrition was carried out based on the comprehensive multi-index evaluation model.Polygonum viviparum L. had the highest nutritional value score(1.43), and Stipa aliena Keng had the lowest(-1.40). Nutritional value of herbage species had a significantly positive correlation with altitude(P&lt;0.01) in the Zoigê Plateau.(3) Based on the nutritional values, herbages in the Zoigê Plateau could be grouped into 3 nutrition PFTs(high, medium and low) by using the Natural Breaks(Jenks) method. 展开更多
关键词 Plant functional types Nutritional value Forage resource management the Zoigê Plateau
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ON MULTIPLE WIENER INTEGRAL EXPANSIONS FOR D'-VALUED NONLINEAR RANDOM FUNCTIONALS
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作者 吴奖伦 《Acta Mathematica Scientia》 SCIE CSCD 1993年第2期220-228,共9页
In this paper, the multiple stochastic integral with respect to a Wiener D'-process is defined. And also it is shown that for a D'-valued nonlinear random functional there exists a sequence of multiple integra... In this paper, the multiple stochastic integral with respect to a Wiener D'-process is defined. And also it is shown that for a D'-valued nonlinear random functional there exists a sequence of multiple integral kernels such that the nonlinear functional can be expanded by series of multiple Wiener integrals of the integral kernels with respect to the Wiener D'-process. 展开更多
关键词 VALUED NONLINEAR RANDOM functionalS ON MULTIPLE WIENER INTEGRAL EXPANSIONS FOR D ONB
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Dynamical distribution of continuous service time model involving non-Maxwellian collision kernel and value functions
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作者 Minfang Zhao Lingting Kong +1 位作者 Miao Liu Shaoyong Lai 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第9期340-348,共9页
The distribution of continuous service time in call centers is investigated.A non-Maxwellian collision kernel combining two different value functions in the interaction rule are used to describe the evolution of conti... The distribution of continuous service time in call centers is investigated.A non-Maxwellian collision kernel combining two different value functions in the interaction rule are used to describe the evolution of continuous service time,respectively.Using the statistical mechanical and asymptotic limit methods,Fokker–Planck equations are derived from the corresponding Boltzmann-type equations with non-Maxwellian collision kernels.The steady-state solutions of the Fokker–Planck equation are obtained in exact form.Numerical experiments are provided to support our results under different parameters. 展开更多
关键词 kinetic theory service time Fokker-Planck equation value function
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Deep reinforcement learning using least-squares truncated temporal-difference
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作者 Junkai Ren Yixing Lan +3 位作者 Xin Xu Yichuan Zhang Qiang Fang Yujun Zeng 《CAAI Transactions on Intelligence Technology》 SCIE EI 2024年第2期425-439,共15页
Policy evaluation(PE)is a critical sub-problem in reinforcement learning,which estimates the value function for a given policy and can be used for policy improvement.However,there still exist some limitations in curre... Policy evaluation(PE)is a critical sub-problem in reinforcement learning,which estimates the value function for a given policy and can be used for policy improvement.However,there still exist some limitations in current PE methods,such as low sample efficiency and local convergence,especially on complex tasks.In this study,a novel PE algorithm called Least-Squares Truncated Temporal-Difference learning(LST2D)is proposed.In LST2D,an adaptive truncation mechanism is designed,which effectively takes advantage of the fast convergence property of Least-Squares Temporal Difference learning and the asymptotic convergence property of Temporal Difference learning(TD).Then,two feature pre-training methods are utilised to improve the approximation ability of LST2D.Furthermore,an Actor-Critic algorithm based on LST2D and pre-trained feature representations(ACLPF)is proposed,where LST2D is integrated into the critic network to improve learning-prediction efficiency.Comprehensive simulation studies were conducted on four robotic tasks,and the corresponding results illustrate the effectiveness of LST2D.The proposed ACLPF algorithm outperformed DQN,ACER and PPO in terms of sample efficiency and stability,which demonstrated that LST2D can be applied to online learning control problems by incorporating it into the actor-critic architecture. 展开更多
关键词 Deep reinforcement learning policy evaluation temporal difference value function approximation
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Research on the Coupled and Coordinated Development of Tourism and Transport in Chongqing Municipality
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作者 Mengmeng Shu 《Proceedings of Business and Economic Studies》 2024年第3期92-101,共10页
By examining the current status of tourism and transport research both domestically and internationally,and analyzing the development trends of Chongqing’s tourism and transport industry,this study evaluates the weig... By examining the current status of tourism and transport research both domestically and internationally,and analyzing the development trends of Chongqing’s tourism and transport industry,this study evaluates the weight indices and performs a coupling and coordination analysis of various indicators of Chongqing’s tourism and transport industry from 2011 to 2019.The following conclusions are drawn:(1)The value of the comprehensive evaluation function for tourism is higher than that of the transport industry,indicating that Chongqing’s tourism industry is in a period of vigorous development;(2)The degree of coupling coordination development between Chongqing’s tourism and transportation industries from 2011 to 2019 is rising.As the coupling coordination stage continues to improve,the level of coupling coordination also improves,with the overall trend showing a progression from mild dysfunction to primary coordination.Based on these conclusions,corresponding countermeasures are proposed to promote the coupling coordination between tourism and transport in Chongqing,and suggestions are made for the overall improvement of the transport industry and the sustainable development of the tourism industry. 展开更多
关键词 Chongqing Municipality TOURISM Transport industry Comprehensive evaluation function value Coupling coordination
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Concepts of keystone species and species importance in ecology
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作者 陆兆华 马玲 国庆喜 《Journal of Forestry Research》 SCIE CAS CSCD 2001年第4期250-252,277,共4页
This paper discussed the keystone species concept and introduced the typical characteristics of keystone species and their identification in communities or ecosystems. Based on the research of the keystone species, th... This paper discussed the keystone species concept and introduced the typical characteristics of keystone species and their identification in communities or ecosystems. Based on the research of the keystone species, the concept of species importance (SI) was first advanced in this paper. The species importance can be simply understood as the important value of species in the ecosystem, which consists of three indexes: species structural important value (SIV), functional important value (FIV) and dynamical important value (DIV). With the indexes, the evaluation was also made on species importance of arbor trees in the Three-Hardwood forests (Fraxinus mandshurica, Juglans mandshurica, and Phellodendron amurense) ecosystem. 展开更多
关键词 Species importance Keystone species Structural important value functional important value Dynamical important value
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Dual Quaternions and Dual Quaternion Vectors 被引量:4
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作者 Liqun Qi Chen Ling Hong Yan 《Communications on Applied Mathematics and Computation》 2022年第4期1494-1508,共15页
We introduce a total order and an absolute value function for dual numbers.The absolute value function of dual numbers takes dual number values,and has properties similar to those of the absolute value function of rea... We introduce a total order and an absolute value function for dual numbers.The absolute value function of dual numbers takes dual number values,and has properties similar to those of the absolute value function of real numbers.We define the magnitude of a dual quaternion,as a dual number.Based upon these,we extend 1-norm,co-norm,and 2-norm to dual quaternion vectors. 展开更多
关键词 Dual number Absolute value function Dual quaternion MAGNITUDE NORM
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Screening and evaluation of reliable traits of upland cotton(Gossypium hirsutum L.)genotypes for salt tolerance at the seedling growth stage 被引量:7
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作者 SIKDER Ripon Kumar WANG Xiangru +6 位作者 JIN Dingsha ZHANG Hengheng GUI Huiping DONG Qiang PANG Nianchang ZHANG Xiling SONG Meizhen 《Journal of Cotton Research》 2020年第2期90-102,共13页
Background:Salt stress significantly inhibits the growth,development,and productivity of cotton because of osmotic,ionic,and oxidative stresses.Therefore,the screening and development of salt tolerant cotton cultivars... Background:Salt stress significantly inhibits the growth,development,and productivity of cotton because of osmotic,ionic,and oxidative stresses.Therefore,the screening and development of salt tolerant cotton cultivars is a key issue towards sustainable agriculture.This study subjected 11 upland cotton genotypes at the seedling growth stage to five different salt concentrations and evaluated their salt tolerance and reliable traits.Results:Several morpho-physiological traits were measured after 10 days of salinity treatment and the salt tolerance performance varied significantly among the tested cotton genotypes.The optimal Na Cl concentration for the evaluation of salt tolerance was 200 mmol·L-1.Membership function value and salt tolerance index were used to identify the most consistent salt tolerance traits.Leaf relative water content and photosynthesis were identified as reliable indicators for salt tolerance at the seedling stage.All considered traits related to salt tolerance indices were significantly and positively correlated with each other except for malondialdehyde.Cluster heat map analysis based on the morpho-physiological salt tolerance-indices clearly discriminated the 11 cotton genotypes into three different salt tolerance clusters.Cluster I represented the salt-tolerant genotypes(Z9807,Z0228,and Z7526)whereas clusters II(Z0710,Z7514,Z1910,and Z7516)and III(Z0102,Z7780,Z9648,and Z9612)represented moderately salttolerant and salt-sensitive genotypes,respectively.Conclusions:A hydroponic screening system was established.Leaf relative water content and photosynthesis were identified as two reliable traits that adequately represented the salt tolerance of cotton genotypes at the seedling growth stage.Furthermore,three salt-tolerant genotypes were identified,which might be used as genetic resources for the salt-tolerance breeding of cotton. 展开更多
关键词 Cotton genotypes Salt stress Screening Membership function value Cluster analysis
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AN INEQUALITY ON THE ZEROS AND POLES OF VECTOR VALUED MEROMORPHIC FUNCTIONS 被引量:1
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作者 吴昭君 《Acta Mathematica Scientia》 SCIE CSCD 2014年第2期380-386,共7页
The author proves that if f : C → C^n is a transcendental vector valued mero-morphic function of finite order and assume, This result extends the related results for meromorphic function by Singh and Kulkarni.
关键词 Characteristic function vector valued meromorphic function ZERO POLE
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Resolution of Grandi’s Paradox as Extended to Complex Valued Functions 被引量:2
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作者 Serdar Beji 《Advances in Pure Mathematics》 2020年第8期447-463,共17页
Grandi’s paradox, which was posed for a real function of the form <span style="white-space:nowrap;">1/(1+ <em>x</em>)</span>, has been resolved and extended to complex valued functio... Grandi’s paradox, which was posed for a real function of the form <span style="white-space:nowrap;">1/(1+ <em>x</em>)</span>, has been resolved and extended to complex valued functions. Resolution of this approximately three-hundred-year-old paradox is accomplished by the use of a consistent truncation approach that can be applied to all the series expansions of Grandi-type functions. Furthermore, a new technique for improving the convergence characteristics of power series with alternating signs is introduced. The technique works by successively averaging a series at different orders of truncation. A sound theoretical justification of the successive averaging method is demonstrated by two different series expansions of the function <span style="white-space:nowrap;">1/(1+ e<sup><em>x</em> </sup>)</span> . Grandi-type complex valued functions such as <span style="white-space:nowrap;">1/(<em>i</em> + <em>x</em>)</span> are expressed as consistently-truncated and convergence-improved forms and Fagnano’s formula is established from the series expansions of these functions. A Grandi-type general complex valued function <img src="Edit_f4efd7cd-6853-4ca4-b4dc-00f0b798c277.png" width="80" height="24" alt="" /> is introduced and expanded to a consistently truncated and successively averaged series. Finally, an unorthodox application of the successive averaging method to polynomials is presented. 展开更多
关键词 Grandi’s Paradox Real and Complex Valued Functions Series Expansions
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Value Evaluation of Water Ecosystem Services——A Case Study of Changshu City 被引量:1
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作者 GAN Yue-yun JIN Hui +1 位作者 CHEN Xing ZHANG Qi-cheng 《Meteorological and Environmental Research》 2012年第10期40-42,共3页
[ Objective] The study aimed to quantitatively assess the values of water ecosystem services. [ Method] Combining the market value, travel cost and restoration cost method, the ecological services and their economic v... [ Objective] The study aimed to quantitatively assess the values of water ecosystem services. [ Method] Combining the market value, travel cost and restoration cost method, the ecological services and their economic values of the lake Taodangmian were assessed from aspects of water supply, recreation and tourism, water purification and biodiversity maintenance. [ Resultl For the lake Taodangmian, its freshwater supply and tourism played more positive roles in the society than the others, while the functions of water purification and biodiversity maintenance brought negative effects, which shows that the ecological environment of Taodangmian has become increasingly worse and needs to be controlled and and protected further. [ Conclusion] The research could provide scientific references for the reasonable exploitation and utilization of water resources. 展开更多
关键词 Water ecosystem Service function values Assessment methods Taodangmian China
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Another Approach to Multiobjective Programming Problems with V-invex Functions 被引量:1
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作者 LIUSan-ming FENGEn-min LIXiao-shen 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2005年第1期101-110,共10页
In this paper, optimality conditions for multiobjective programming problems having V-invex objective and constraint functions are considered. An equivalent multiobjective programming problem is constructed by a modif... In this paper, optimality conditions for multiobjective programming problems having V-invex objective and constraint functions are considered. An equivalent multiobjective programming problem is constructed by a modification of the objective function.Furthermore, a (α, η)-Lagrange function is introduced for a constructed multiobjective programming problem, and a new type of saddle point is introduced. Some results for the new type of saddle point are given. 展开更多
关键词 efficient solution V-invex function vector valued saddle point multiobjective programming vector valued η)-Lagrange function
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A kinetic description of the impact of agent competence and psychological factors on investment decision-making
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作者 胡春华 陈弘婧 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第8期520-530,共11页
The kinetic theory is employed to analyze influence of agent competence and psychological factors on investment decision-making.We assume that the wealth held by agents in the financial market is non-negative,and agen... The kinetic theory is employed to analyze influence of agent competence and psychological factors on investment decision-making.We assume that the wealth held by agents in the financial market is non-negative,and agents set their own investment strategies.The herding behavior is considered when analyzing the impact of an agent's psychological factors on investment decision-making.A nonlinear Boltzmann model containing herding behavior,agent competence and irrational behavior is employed to investigate investment decision-making.To characterize the agent's irrational behavior,we utilize a value function which includes current and ideal-investment decisions to describe the agent's irrational behavior.Employing the asymptotic procedure,we obtain the Fokker-Planck equation from the Boltzmann equation.Numerical results and the stationary solution of the obtained Fokker-Planck equation illustrate how herding behavior,agent competence,psychological factors,and irrational behavior affect investment decision-making,i.e.,herding behavior has both advantages and disadvantages for investment decision-making,and the agent's competence to invest helps the agent to increase income and to reduce loss. 展开更多
关键词 kinetic theory investment decisions Fokker-Planck equation value function
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Lipschitz continuity of the optimal value function and KKT solution set in indefinite quadratic programs
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作者 HAN You-pan CHEN Zhi-ping ZHANG Feng 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2015年第1期102-110,共9页
When all the involved data in indefinite quadratic programs change simultaneously, we show the locally Lipschtiz continuity of the KKT set of the quadratic programming problem firstly, then we establish the locally Li... When all the involved data in indefinite quadratic programs change simultaneously, we show the locally Lipschtiz continuity of the KKT set of the quadratic programming problem firstly, then we establish the locally Lipschtiz continuity of the KKT solution set. Finally, the similar conclusion for the corresponding optimal value function is obtained. 展开更多
关键词 quadratic program Lipschitz continuity value function feasible solution KKT solution set.
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Continuity of the optimal value function and optimal solutions of parametric mixed-integer quadratic programs
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作者 CHEN Zhi-ping HAN You-pan Department of Scientific Computing and Applied Software, Faculty of Science, Xi’an Jiaotong University, Xi’an 710049, China 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2010年第4期391-399,共9页
To properly describe and solve complex decision problems, research on theoretical properties and solution of mixed-integer quadratic programs is becoming very important. We establish in this paper different Lipschitz-... To properly describe and solve complex decision problems, research on theoretical properties and solution of mixed-integer quadratic programs is becoming very important. We establish in this paper different Lipschitz-type continuity results about the optimal value function and optimal solutions of mixed-integer parametric quadratic programs with parameters in the linear part of the objective function and in the right-hand sides of the linear constraints. The obtained results extend some existing results for continuous quadratic programs, and, more importantly, lay the foundation for further theoretical study and corresponding algorithm analysis on mixed-integer quadratic programs. 展开更多
关键词 MIXED-INTEGER quadratic program optimal value function optimal solution.
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HAUSDORFF DIMENSION OF GENERALIZED STATISTICALLY SELF-AFFINE FRACTALS
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作者 余旌胡 丁立新 《Acta Mathematica Scientia》 SCIE CSCD 2004年第3期421-433,共13页
The authors consider generalized statistically self-affine recursive fractals K with random numbers of subsets on each level. They obtain the Hausdorff dimensions of K without considering whether the subsets on each l... The authors consider generalized statistically self-affine recursive fractals K with random numbers of subsets on each level. They obtain the Hausdorff dimensions of K without considering whether the subsets on each level are non-overlapping or not. They also give some examples to show that many important sets are the special cases of their models. 展开更多
关键词 Self-affine contraction map statistically recursive set statistically self-affine set Hausdorff measure Hausdorff dimension singular value function
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Optimal Switching Control for Nonlinear Systems in A Finite Duration
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作者 MU Xiao-wu LIU Hai-jun 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2006年第2期185-195,共11页
This paper proposes a optimal control problem for a general nonlinear systems with finitely many admissible control settings and with costs assigned to switching of controls. With dynamic programming and viscosity sol... This paper proposes a optimal control problem for a general nonlinear systems with finitely many admissible control settings and with costs assigned to switching of controls. With dynamic programming and viscosity solution theory we show that the switching lower-value function is a viscosity solution of the appropriate systems of quasi-variational inequalities(the appropriate generalization of the Hamilton-Jacobi equation in this context) and that the minimal such switching-storage function is equal to the continuous switching lower-value for the game. With the lower value function a optimal switching control is designed for minimizing the cost of running the systems. 展开更多
关键词 switching systems optimal control viscosity solution value function cost function
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COMPLEX INTERPOLATION OF L_(p)(C,H)SPACES WITH RESPECT TO CULLEN-REGULAR
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作者 Kaili HE Jianxun HE Zhenzhen LOU 《Acta Mathematica Scientia》 SCIE CSCD 2022年第2期774-788,共15页
The aim of this paper is to prove a new version of the Riesz-Thorin interpolation theorem on L^(P)(C,H).In the sense of Cullen-regular,we show Hadamard’s three-lines theorem by means of the Maximum modulus principle ... The aim of this paper is to prove a new version of the Riesz-Thorin interpolation theorem on L^(P)(C,H).In the sense of Cullen-regular,we show Hadamard’s three-lines theorem by means of the Maximum modulus principle on a symmetric slice domain.In addition,two applications of the Riesz-Thorin theorem are presented.Finally,we investigate two kinds of Calderón’s complex interpolation methods in LP(C,H). 展开更多
关键词 Hadamard’s three-lines theorem complex interpolation quaternion valued function space Cullen-regular
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Multiagent reinforcement learning through merging individually learned value functions
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作者 张化祥 黄上腾 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2005年第3期346-350,共5页
In cooperative multiagent systems, to learn the optimal policies of multiagents is very difficult. As the numbers of states and actions increase exponentially with the number of agents, their action policies become mo... In cooperative multiagent systems, to learn the optimal policies of multiagents is very difficult. As the numbers of states and actions increase exponentially with the number of agents, their action policies become more intractable. By learning these value functions, an agent can learn its optimal action policies for a task. If a task can be decomposed into several subtasks and the agents have learned the optimal value functions for each subtask, this knowledge can be helpful for the agents in learning the optimal action policies for the whole task when they are acting simultaneously. When merging the agents’ independently learned optimal value functions, a novel multiagent online reinforcement learning algorithm LU-Q is proposed. By applying a transformation to the individually learned value functions, the constraints on the optimal value functions of each subtask are loosened. In each learning iteration process in algorithm LU-Q, the agents’ joint action set in a state is processed. Some actions of that state are pruned from the available action set according to the defined multiagent value function in LU-Q. As the items of the available action set of each state are reduced gradually in the iteration process of LU-Q, the convergence of the value functions is accelerated. LU-Q’s effectiveness, soundness and convergence are analyzed, and the experimental results show that the learning performance of LU-Q is better than the performance of standard Q learning. 展开更多
关键词 reinforcement learning MULTIAGENT value function
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BSDES IN GAMES,COUPLED WITH THE VALUE FUNCTIONS.ASSOCIATED NONLOCAL BELLMAN-ISAACS EQUATIONS
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作者 郝涛 李娟 《Acta Mathematica Scientia》 SCIE CSCD 2017年第5期1497-1518,共22页
We establish a new type of backward stochastic differential equations(BSDEs)connected with stochastic differential games(SDGs), namely, BSDEs strongly coupled with the lower and the upper value functions of SDGs, wher... We establish a new type of backward stochastic differential equations(BSDEs)connected with stochastic differential games(SDGs), namely, BSDEs strongly coupled with the lower and the upper value functions of SDGs, where the lower and the upper value functions are defined through this BSDE. The existence and the uniqueness theorem and comparison theorem are proved for such equations with the help of an iteration method. We also show that the lower and the upper value functions satisfy the dynamic programming principle. Moreover, we study the associated Hamilton-Jacobi-Bellman-Isaacs(HJB-Isaacs)equations, which are nonlocal, and strongly coupled with the lower and the upper value functions. Using a new method, we characterize the pair(W, U) consisting of the lower and the upper value functions as the unique viscosity solution of our nonlocal HJB-Isaacs equation. Furthermore, the game has a value under the Isaacs’ condition. 展开更多
关键词 Mc Kean-Vlasov SDE BSDE coupled with the lower and the upper value functions dynamic programming principle mean-field BSDE viscosity solution coupled nonlocal HJB-Isaacs equation Isaacs' condition
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