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通过假设被接种者具有部分免疫,建立了一类具有潜伏期和接种的SEIR传染病模型,借助再生矩阵得到了确定此接种模型动力学行为的基本再生数.当基本再生数小于1时,模型只有无病平衡点;当基本再生数大于1时,除无病平衡点外,模型还有唯一的地方病平衡点.借助Liapunov函数,证明了无病平衡点和地方病平衡点的全局稳定性. 相似文献
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Advertising in a Differential Oligopoly Game 总被引:2,自引:0,他引:2
We illustrate a differential oligopoly game where firms compete à la Cournot in homogeneous goods in the market phase and invest in advertising activities aimed at increasing the consumers reservation price. Such investments produce external effects, characterizing the advertising activity as a public good. We derive the open-loop and closed-loop Nash equilibria, and show that the properties of the equilibria depend on the curvature of the market demand function. The comparative assessment of these equilibria shows that the firms advertising efforts are larger in the open-loop equilibrium than in the closed-loop equilibrium. We also show that a cartel involving all the firms, setting both output levels and advertising efforts, may produce a steady state where the social welfare level is higher than the social welfare levels associated with both open-loop and closed-loop noncooperative settings. 相似文献
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能源是经济可持续发展的重要的物质基础.在能源开发时间路径上,不可再生资源面临资源储量的约束,可再生资源面临技术水平的约束.R&D投资可以促进技术进步.但是不论是可耗竭资源的储量还是技术进步水平都具有很大的不确定性.就此情形构建了基于两类能源的生产者利润最大化为目标的随机动态微分博弈,研究不确定性对能源市场均衡的影响. 相似文献
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研究开采成本等重要因素对不可再生资源开采的影响.假定有N个厂商对不可再生资源进行开采,其面临的市场需求价格弹性为常数,开采成本是开采量的线性函数.利用微分对策理论,分析该寡头市场中各个厂商的均衡开采策略.研究表明,开采成本对是否开采、开采速度、结束时点等有重要影响.同时,本文还与某些经典论文进行了简要比较. 相似文献
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The solutions of the partial realization problem have to satisfy a finite number of interpolation conditions at . The minimal degree of an interpolating deterministic system is called the algebraic degree or McMillan degree of the partial covariance sequence and is easy to compute. The solutions of the partial stochastic realization problem have to satisfy the same interpolation conditions and have to fulfill a positive realness constraint. The minimal degree of a stochastic realization is called the positive degree. In the literature, solutions of the partial realization problem are parameterized by the Kimura–Georgiou parameterization. Solutions of the partial stochastic realization problem are then obtained by checking the positive realness constraint for the interpolating solutions of the corresponding partial realization problem. In this paper, an alternative parameterization is developed for the solutions of the partial realization problems. Both the solutions of the partial and partial stochastic realization problem are analyzed in this parameterization, while the main concerns are the minimality and the uniqueness of the solutions. Based on the structure of the parameterization, a lower bound for the positive degree is derived. 相似文献
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针对不确定环境下的合作博弈问题,引入置信与丘奎特积分,给出了其均衡定义及求解方法。将上述方法应用到公司治理结构中,对经理人与股东在不确定性环境下的合作博弈进行求解,通过比较其均衡与非合作博弈均衡结果,说明该方法能够给双方带来更多的收益,从而实现帕累托改进。 相似文献
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Optimal Ordering Policy for Deteriorating Items with Partial Backlogging under Permissible Delay in Payments 总被引:1,自引:0,他引:1
In 1985, Goyal developed an Economic order quantity (EOQ) model under conditions of permissible delay in payments. Jamal et
al. then generalized Goyal’s model for deteriorating items with completely backlogging. However, they only ran several simulations
to indicate that the total relevant cost may be convex. Recently, Teng amended Goyal’s model by considering the difference
between unit price and unit cost, and provided an alternative conclusion that it makes economic sense for some retailers to
order less quantity and take the benefits of the permissible delay more frequently. However, he did not consider deteriorating
items and partial backlogging. In this paper, we establish a general EOQ model for deteriorating items when the supplier offers
a permissible delay in payments. For generality, our model allows not only the partial backlogging rate to be related to the
waiting time but also the unit selling price to be larger than the unit purchase cost. Consequently, the proposed model includes
numerous previous models as special cases. In addition, we mathematically prove that the total relevant cost is strictly pseudo-convex
so that the optimal solution exists and is unique. Finally, our computational results reveal six managerial phenomena. 相似文献
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保持一个等价关系的部分变换半群 总被引:4,自引:0,他引:4
设X是一个集合,|X|≥3. Px为集合X上所有部分变换构成的半群.设E是集合X的一个等价关系.定义 PE(X)={f∈Px:(A)x,y∈domf,(x,y)∈E(→)f(x),f(y)∈E} 则PE(X)作成PX的一个子半群.本文讨论半群PE(X)的格林关系和正则性,并研究当等价关系E满足什么条件时,半群PE(X)是富足半群. 相似文献
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Consider the partly linear model Y = xβ + g(t) + e where the explanatory x is erroneously measured,and both t and the response Y are measured exactly,the random error e is a martingale difference sequence.Let x be a surrogate variable observed instead of the true x in the primary survey data.Assume that in addition to the primary data set containing N observations of {(Y_j,x_j,t_j)_(j=n+1)~(n+N),the independent validation data containing n observations of {(x_j,x_j,t_j)_(j=1)~n} is available.In this paper,a semiparametric method with the primary data is employed to obtain the estimator of β and g(·) based on the least squares criterion with the help of validation data.The proposed estimators are proved to be strongly consistent.Finite sample behavior of the estimators is investigated via simulations too. 相似文献
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Andreas Klein 《Designs, Codes and Cryptography》2004,31(3):221-226
Ovoids in finite polar spaces are related to many other objects in finite geometries. In this article, we prove some new upper bounds for the size of partial ovoids in Q
–(2n+1,q) and W(2n+ 1,q). Further, we give a combinatorial proof for the non-existence of ovoids of H(2n +1,q
2) for n>q
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产学研合作是科技与经济结合的有效形式,协同创新理论对产学研合作提出了更高的要求。从协同创新视角出发,利用基于有限理性的演化博弈理论构建了企业与学研机构间的协同合作决策博弈模型,并对策略选择进行稳定性分析。理论研究和数值仿真结果表明:当企业和学研机构在协同合作中获得的经济收益净值大于其选择中途放弃获得的经济收益时,双方才会全部选择协同合作策略;产学研协同合作总收益、收益分配系数、赔偿系数和协同合作成本对企业和学研机构的决策结果有显著的影响,但作用机制有所不同;政府对产学研协同合作的资助和惩罚机制对企业和学研机构选择协同合作策略有促进的作用,但应将资助和惩罚力度控制在一定范围内发挥其最大激励效用。 相似文献
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The paper presents a stochastic differential game model of a common-property commercial fishery and determines a feedback Nash equilibrium of the game. Closed-form expressions for the value functions, the equilibrium harvesting strategies, and stationary distributions of the fish stock are derived. Sensitivity analyses with respect tot he model parameters are carried out. The paper also considers equilibrium outcomes under joint maximization and surplus maximization. In the latter case, an optimal market size (i.e., number of firms) is identified.The research of the first author was supported in part by Grant 5.20.31.02 from the Danish Research Council for the Social Sciences. The research of the second author was supported in part by the CRGC Fund of the University of Hong Kong. The authors would like to thank the editor for constructive comments. 相似文献
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In this paper we develop a heuristic algorithm, based on Scatter Search, for project scheduling problems under partially renewable
resources. This new type of resource can be viewed as a generalization of renewable and non-renewable resources, and is very
helpful in modelling conditions that do no fit into classical models, but which appear in real timetabling and labor scheduling
problems. The Scatter Search algorithm is tested on existing test instances and obtains the best results known so far. 相似文献
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A Markov model with a coordination parameter isdeveloped to depict coordination and cooperation decisionprocesses in 2 × 2 game relationships. The parameters ofthe model can be used to define and measure various forms ofinfluence. The model is applied to data collected using aprisoner's dilemma payoff structure to represent thesuperior-subordinate relationship. The results demonstrate theusefulness of the model and the measures of influence. Superiorsand subordinates are more likely to coordinate following mutualcooperation, achieving matching behaviors more frequently thanan independent-decisions model would predict. Subordinates showslightly more influence over leaders' behaviors than vice versa. 相似文献