Characterization of the core in games with restricted cooperation

Games with restricted cooperation describe situations in which the players are not completely free in forming coalitions. The restrictions in coalition formation can be attributed to economic, hierarchical, political or ethical reasons. In order to manage these situations, the model includes a collection of coalitions which determines the feasible agreements among the agents. The purpose of this paper is to extend the characterization of the core of a cooperative game, made by Peleg [International Journal of Game Theory 15 (1986) 187–200; Handbook of Game Theory with Economic Applications, vol. I. Elsevier Science Publishers B.V., pp. 397–412] to the context of games with restricted cooperation. In order to make the approach as general as possible, we will consider classes of games with restricted cooperation in which the collection of feasible coalitions has a determined structure, and we will impose conditions on that structure to generalize the Peleg’s axiomatization.     

A Neuro-Fuzzy Approach to Optimize Hierarchical Recurrent Fuzzy Systems

To simplify the definition of fuzzy systems or to reduce its complexity hierarchical structures can be used. Thus, more transparent rule bases that are also easier to maintain can be designed. Furthermore, it is sometimes necessary to use time delayed input or to reuse time delayed output from the fuzzy system itself to obtain a rule base that describes the analyzed problem appropriately. This leads to hierarchical recurrent architectures that have increased approximation capabilities since they are able to store information of the past. In this article we present a neuro-fuzzy model that can be used to optimize hierarchical recurrent fuzzy rule bases if training data is available. Furthermore, we present an approach to learn initial rule bases from data using rule templates.     

Existence and uniqueness of solutions for a hierarchical system of two age-structured populations

We propose a class of new hierarchical model for the evolution of two interacting age-structured populations, which is a system of integro-partial differential equations with global feedback boundary conditions and may describe the interactions such as competition, cooperation and predator-prey relation. Based upon a group of natural conditions, the existence and uniqueness of solutions on infinite time interval are proved by means of fixed point and extension principle, and the continuous dependence of the solution on the initial age distribution is established. These results lay a sound basis for the investigation of stability, controllability and variable optimal control problems.     

Inverse Stackelberg Public Goods Game with Multiple Hierarchies Under Global and Local Information Structures

This paper studies the inverse Stackelberg game with multiple hierarchies under global and local information structures, where the players have discrete strategy spaces. For the classic public goods game, we solve the pure-strategy inverse Stackelberg equilibria under three typical hierarchical structures. The results reveal some counterintuitive characteristics within the systems with hierarchies, such as that the cooperation does not increase with the return rate at the equilibria. Furthermore, by defining a local information structure, we give an estimate of the fewest hierarchies required for full cooperation, which can be a constant multiple of the logarithm or square root of the population size or of the population size itself, according to different information structures and return rates. This paper proposes a novel mechanism to play the game and promote cooperation. Both the formulation and analysis method are different from existing works, and the results can find their ample implications in practice, which might help decision making in hierarchical systems.     

On the synchronization of different chaotic oscillators

The synchronization of two different chaotic oscillators is studied, based on an open-loop control – the entrainment control. We consider two types of synchronization: complete synchronization and effectively complete synchronization. The sufficient conditions that two different systems can be synchronized by this method is discussed. Furthermore, a hierarchical idea to synchronize multiple chaotic subsystems is proposed.     

Interactive Visualization of Hierarchically Structured Data

We introduce methods for visualization of data structured along trees, especially hierarchically structured collections of time series. To this end, we identify questions that often emerge when working with hierarchical data and provide an R package to simplify their investigation. Our key contribution is the adaptation of the visualization principles of focus-plus-context and linking to the study of tree-structured data. Our motivating application is to the analysis of bacterial time series, where an evolutionary tree relating bacteria is available a priori. However, we have identified common problem types where, if a tree is not directly available, it can be constructed from data and then studied using our techniques. We perform detailed case studies to describe the alternative use cases, interpretations, and utility of the proposed visualization methods.     

考虑质量偏好的两阶段服务供应链质量控制策略

研究了一个集成商和一个提供商所组成的服务供应链的质量控制问题。考虑集成商的质量缺陷承诺和提供商的质量偏好,并将提供商的质量活动区分为质量改进和质量保持两个阶段,分别建立了服务供应链成员的效用函数,同时考虑服务供应链成员的竞争与合作,运用博弈理论,优化得到单阶段与两阶段时,集成商的最优服务价格和质量缺陷承诺,以及提供商的最优服务质量改进程度。最后,通过对比分析及数值仿真发现,考虑两阶段质量控制较单阶段情形,更有利于服务供应链较长期限内获得更多效用。其次,服务提供商质量偏好对服务供应链单阶段与两阶段下的最优效用和质量控制策略均产生一定影响。     

Nesterov’s smoothing technique and minimizing differences of convex functions for hierarchical clustering

A bilevel hierarchical clustering model is commonly used in designing optimal multicast networks. In this paper, we consider two different formulations of the bilevel hierarchical clustering problem, a discrete optimization problem which can be shown to be NP-hard. Our approach is to reformulate the problem as a continuous optimization problem by making some relaxations on the discreteness conditions. Then Nesterov’s smoothing technique and a numerical algorithm for minimizing differences of convex functions called the DCA are applied to cope with the nonsmoothness and nonconvexity of the problem. Numerical examples are provided to illustrate our method.     

Subgame Consistent Cooperative Solutions in Stochastic Differential Games

Subgame consistency is a fundamental element in the solution of cooperative stochastic differential games. In particular, it ensures that: (i) the extension of the solution policy to a later starting time and to any possible state brought about by the prior optimal behavior of the players would remain optimal; (ii) all players do not have incentive to deviate from the initial plan. In this paper, we develop a mechanism for the derivation of the payoff distribution procedures of subgame consistent solutions in stochastic differential games with transferable payoffs. The payoff distribution procedure of the subgame consistent solution can be identified analytically under different optimality principles. Demonstration of the use of the technique for specific optimality principles is shown with an explicitly solvable game. For the first time, analytically tractable solutions of cooperative stochastic differential games with subgame consistency are derived.     

随机市场中均值-方差模型最优投资策略的时间不相容性及其修正

由于方差算子在动态规划意义下不可分,导致随机市场中多期均值一方差模型的最优投资策略不满足时间相容性,即Bellman最优性原理．为此,首先提出了随机市场中比Bellman最优性原理更弱的时间相容性,并证明在投资区间的任意中间时刻,当投资者的财富不超过某一给定的财富阈值时,最优投资策略满足弱时间相容性;当投资者的财富超过该阈值时,最优投资策略将不再是弱时间相容的,且导致投资者变为非理性,即他会同时极小化终期财富的均值和方差．在这种情形下,通过放松自融资约束,对最优投资策略进行了修正,使得其满足：修正策略可使投资者回归理性;相对于终期财富,修正策略可以获得与最优投资策略相同的均值和方差．在策略修正过程中,投资者可以从市场中获得一个严格正的现金流．这些结果表明修正策略要优于原最优投资策略,拓展了现有关于确定市场下多期均值．方差模型的求解以及策略时间相容性的结论．     

政府购买公共服务下普惠性学前教育推进的多方演化博弈分析

作为我国政府惠及民生的政策追求和扩大我国学前教育规模并提升质量的重要举措,普惠性学前教育的推进与发展可以缓解我国当前“入园难、入园贵”问题,满足多层次多元化的学前教育需求。在分析了普惠性学前教育推进主体相互关系的基础上构建了“地方政府部门-普惠性学前教育供给机构-适龄幼儿家庭”三者之间的演化博弈模型,分析了三方策略选择与行为演化的影响因素,确立了各方行为趋于稳定状态的条件。研究表明,任一博弈主体行为的演化及其趋势均与另两个博弈主体的策略选择紧密相关;降低学前教育供给机构与政府的合作成本、增加其合作的超额收益,同时增大双方不合作的损失,并降低幼儿家庭及公众的参与成本,提高其参与收益,是推进普惠性学前教育发展的关键。     

带有限反馈下层的二层规划问题的部分合作模型

对下层最优反馈为离散有限多个的二层规划问题的部分合作模型进行探讨. 当下层的合作程度依赖于上层的决策变量时, 给出一个确定合作系数函数的一般方法, 进而得到一个新的部分合作模型. 在适当地假设下, 可保证所给的部分合作模型一定可以找到比悲观解要好的解, 并结合新的部分合作模型对原不适定问题进行分析, 得到了一些有益的结论. 最后以实际算例说明了所给部分合作模型的可行性.     

Power contexts and their concept lattices

We introduce a framework for the study of formal contexts and their lattices induced by the additional structure of self-relations on top of the traditional incidence relation. The induced contexts use subsets as objects and attributes, hence the name power context and power concept. Six types of new incidence relations are introduced by taking into account all possible combinations of universal and existential quantifiers as well as the order of the quantifications in constructing the lifted power contexts. The structure of the power concept lattice is investigated through projection mappings from the baseline objects and attributes to those of the power context, respectively. We introduce the notions of extensional consistency and intensional consistency, corresponding to the topological notions of continuity in the analogous setting when concepts are viewed as closed sets. We establish Galois connections for these notions of consistency. We further introduce the notion of faithfulness for the first type of lifted incidence relation based on the fact that it can be equivalently characterized by a concept-faithful morphism. We also present conditions under which the power concept lattice serves as a factor lattice of the base concept lattice.     

How Crucial is Cooperation in Mitigating World Climate? Analysis with World-MARKAL

In order to study the conditions for a World self-enforcing agreement on climate change, we model cooperative and non-cooperative World climate strategies with an integrated version of the 15-region techno-economic MARKAL model in which abatement costs and climate related damages are both included. We first explain why the use of a technology oriented model may add value to the analysis of global GHG strategies. Based on the empirical finding of linear cumulative climate damages, the computation of Nash equilibrium can be reduced to solving a series of 15 independent linear programs, one per region. Moreover, assuming interregional transfers to share the global surplus of cooperation, our work adopts the point of view of dynamic partial equilibrium computation coupled with cooperative game-theoretic principles. The results illustrate how the non-cooperative strategy is closer to the base case than to the cooperative strategy, and the amount of side-payments sufficient to guarantee the stability of the cooperative strategy are calculated with four different rules. The internal (in)stability of farsighted coalitions without transfers (non-cooperation) is also analyzed. The current project appears to be the first one of the sort using a large and detailed technology explicit model such as MARKAL.     

A structure preserving approach to the simulation of non-smooth dynamics

The investigated multibody dynamics involve perfectly elastic, partially elastic and perfectly plastic contacts and a structure preserving approach is used in forward dynamics and optimal control simulations. The applied mechanical integrator is based on a constrained version of the Lagrange-d’Alembert principle and it represents exactly the behaviour of the analytical solution concerning the consistency of momentum maps and symplecticity: it is called symplectic momentum scheme. To guarantee the geometric exactness during the establishing or releasing of contacts, the non-smooth problem is solved including the computation of the contact configuration, time and force, instead of relying on a smooth approximation of the contact problem via a penalty potential. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Existence of frequency modes coupling seismic waves and vibrating tall buildings

We prove in this paper an existence result for frequency modes coupling seismic waves and vibrating tall buildings. The derivation from physical principles of a set of equations modeling this phenomenon was done in previous studies. In this model all vibrations are assumed to be anti-plane and time harmonic so the two dimensional Helmholtz equation can be used. A coupling frequency mode is obtained once we can determine a wavenumber such that the solution of the corresponding Helmholtz equation in the lower half plane with relevant Neumann and Dirichlet conditions at the interface satisfies a specific integral equation at the base of an idealized tall building. Although numerical simulations suggest that such wavenumbers should exist, as far as we know, to date, there is no theoretical proof of their existence. This is what this present study offers to provide.     

双边市场异业合作网络平台的定价策略

本文以网络平台异业合作为背景,在Hotelling模型框架下,基于双边用户都是部分多归属的假定,结合平台采取异业合作可以提高用户固有收益这一前提,分析了产品和服务的差异化程度、拥挤效应及组间网络外部性强度对网络平台定价策略的影响。结果显示,双边用户的组间网络外部性强度不同时,随着拥挤效应的增强或产品和服务的差异化程度的提高,无论是在位平台还是采取异业合作的新进入平台,都会对一边用户提高,而对另一边用户降低收取的交易费;组间网络外部性强度相同时,平台对双边用户收取的交易费相同,且只与用户固有收益及交易量有关。研究表明,新进入市场的网络平台不应采取传统双边市场中常用的价格战策略来争夺市场份额,而应积极采取异业合作,通过提供优质优价的产品和服务来同在位平台竞争。     

Multiple objectives decomposition–coordination methods for hierarchical organizations

In this paper, the integration of goal programming models and hierarchical programming models is analyzed. The systems under study are assumed to consist of interconnected subsystems with multiple goals in each. Three possible cases regarding the number of decision makers will be considered: (1) one decision maker for the overall goals and one decision maker for each subsystem, (2) conflicting decision makers who are interested in their subsystems, and (3) just one decision maker for the overall system. Next, conditions are stated under which the problem of obtaining satisfying solutions for problems (1) and (3) can be reduced to the problem of obtaining satisfying solutions for the case (2). In order to determine such solutions, hierarchical techniques which exploit the structure of a decomposable system are analyzed. The empirical implementation of the two algorithms proposed shows their efficiency in terms of processing time.     

Varying routes to the top: identifying different strategies in the MBA marketplace

The market for MBA degrees is changing rapidly. As this market tends to maturity,an increase in the number of universities offering these degrees is evident, andalso in the different formats in which these degrees are offered. In thisincreasingly crowded marketplace, there exist two main sources of informationthat buyers (students as well as prospective employers of MBA students) can useto assess the products on offer—whether or not a Business school/MBAprogramme is accredited, and also the position of the school in availablerankings, a number of which are regularly published. Playing ‘the rankingsgame’ is one that occupies the time and effort of many MBA directorsglobally, as they all try to edge their way upwards in order to attract more andbetter students. The problem with an ordinal ranking, though, is that itsuggests too readily that it is based upon a unidimensional measure. We use thedata behind one of these rankings, that of the Financial Times top 100,full-time MBA programmes in 2008, in order to explore to what extent schools areusing different routes to try to improve their rankings. Using a variety ofmultivariate statistical tools, we base our analysis on the three underlyingfactors of alumni career progress, diversity, and idea generation. What emergesis a clearer picture of the extent to which programmes that are ranked veryclosely do, in fact, base their success on very different routes to the top.