基于Nearest-Biclusters协作过滤技术的效用图结构学习算法

在多议题协商研究中,议题之间的依赖关系增加了协商Agent效用函数的复杂性,从而使得多议题协商变得更加困难.基于效用图的多议题依赖协商模型是体现议题间依赖关系的多议题协商模型.在该协商模型中,协商双方仅需要较少的协商步数就能够找到满足Pareto效率的协商结局.如何有效地学习买方Agent的效用图结构是该协商模型的关键.文中基于Nearest-Biclusters协作过滤技术的思想提出了一种新的效用图结构学习算法(NBCFL算法).该算法首先利用Nearest-Biclusters协作过滤技术发现买方偏好的局部匹配特性,提取与当前买方Agent类型相同的买方Agent所产生的协商历史记录,然后通过计算各议题间的依赖度学习买方Agent的效用图结构.实验表明在参与协商的买方Agent类型不同的条件下,NBCFL算法比IBCFL算法能更好地学习买方Agent的效用图结构.     

基于双边多议题的Pareto最优协商研究

研究完全信息情况下的双边多议题协商问题,提出一种双方反提议决策模型,在每一轮反提议生成过程中,提议方在满足自身效用在该轮的保留效用水平下,最大化对方的效用,从而使协商结果达到Pareto最优,同时对双方在不同让步策略下的协商结果进行算例分析,为基于双方合作的完全信息协商提供理论参考。     

基于Agent的双边多议题协商算法

双边多议题协商是一个复杂的动态交互过程。解决Agent在对环境和对方信息不全知的情况下通过协商达成一致并最大化自身效用是非常重要的。为了寻求Pareto效率解,提出了一种在无中介参与的情况下双方通过多轮相互探测求解的方法。实验分析了偏好对协商过程的影响并说明了该算法是一种在较低计算代价下求得Pareto效率解的有效双边多议题协商算法。     

多Agent多阶段一对多协商模型

为解决多Agent一对多、多议题协商问题,提出了具有议题属性协商阶段的多阶段协商模型,设计了一种根据Agent让步幅度变化所形成的曲线来判定Agent类型和使用何种协商方法的协商策略.详细地分析了多Agent、多阶段一对多协商的协商过程.将三角模糊数多属性决策方法引入到多Agent协商过程中降低了决策者评估对方所提出方案的难度,能更自然地对不同方案的优劣进行排序.模拟算例表明,该模型有效且可行,为多Agent协商提供可参考的模型和求解算法.     

基于GAI多属性依赖的协商模型

多属性之间的依赖关系增加协商Agent效用函数的复杂性,从而也增加多属性协商问题的复杂度.本文提出一种基于GAI多属性依赖的协商模型.该模型使用GAI分解将协商Agent的非线性效用函数表示为依赖属性子集的子效用之和.在协商过程中,协商双方采用不同的让步策略和提议策略来改变提议的内容.卖方Agent利用本文提出的GAI网合并算法将协商双方的GAI网合并,并利用生成的GAI树产生使社会福利评估值最大的提议.实验表明当买方Agent采用局部让步策略且卖方Agent采用全局让步策略时,协商双方能够在有限的协商步内达到接近Pareto最优的协商结局.     

基于整合效用的多议题协商优化

在限时条件下的Agent之间的多议题协商中,最差的结果是没有达成协定.由于某一个议题没有达到平衡点而使得整个协商失败是影响协商效用的一个重要因素.给出了一个多议题整合效用评估机制,利用多议题整合效用中各议题因子之间的相关性进行保留值向量的等效置换,优化协商效用评估,在保证协商参与者整体协商效用的前提下动态放宽某个议题的保留值,促使协商双方避免协商僵局,快速达成一致的协定.实验数据表明,该机制有效地解决了协商僵局问题,提高了协商的成功率.     

一种劝说式多Agent多议题协商方法

多Agent系统中的协商问题往往由许多议题组成,导致问题空间十分庞大．传统的协商方法通过对问题空间进行穷尽搜索来找到最优解,并不适合多议题协商．而且,传统的方法不考虑协商偏好变化的情况,使得Agent在不完全及不正确环境下找到的最优解并不合理．提出一种劝说式多Agent多议题协商方法．借助信念修正这一有效的推理工具,协商Agent能够在协商过程中接受协商对手的劝说,考虑对手对协商议题的偏好,并根据一种基于辩论的信念修正方法调整自身的偏好．这样就能够使协商Agent对变化的协商环境具备适应性,从而提高协商的效率及正确率,快速准确地达成协议．     

一种多Agent多议题的协商模型

协商是多Agent系统实现协作、协调和冲突消解的关键技术。本文分析了协商问题的实质和协商过程,提出了一种支持多轮协商的多Agent多议题协商模型。模型中引入了Agent类型的概念,在信息不完全的条件下,协商Agent通过推测协商对手的类型来指导自身的提议策略和协商战术,使提议更具针对性,避免了盲目性,从而节约了协商时间,提高了协
商质量。     

基于对手案例学习的多议题协商决策模型

为了解决多Agent系统(MAS)协商双方在信息对称情况下的自动协商问题,提出了一种用基于支持向量机算法的间接学习对手协商态度的协商方法,提出了不完全信息条件下基于案例和对策论的Agent多议题Pareto最优协商模型,通过支持向量机的方法来学习协商轨迹,得到协商对手在每个协商项的态度,然后利用学习得到的对手协商态度,构造了一个协商的决策模型,此模型能同时基于对手的态度和自身的偏好来做出协商决策。最后通过实验验证了该方法的先进性。     

基于效用图的依赖关系与协商策略研究

依赖关系一直是多议题协商的重点和难点.在基于依赖关系的多议题协商背景下,对依赖关系和依赖度进行了严格的定义和度量.在协商过程中,协商Agent强化了自身的协商策略,并使用多目标遗传协商算法对协商进行优化.实验结果表明,在该协商背景下依赖关系的定义以及依赖强度的度量是合理的,卖方Agent使用多目标遗传协商算法和各种协商策略是可行的,并取得了较好的协商效果,且使协商结果迭到了pareto最优.     

Compromising Adjustment Strategy Based on TKI Conflict Mode for Multi‐Times Bilateral Closed Negotiations

Bilateral multi‐issue closed negotiation is an important class for real‐life negotiations. Usually, negotiation problems have constraints such as a complex and unknown opponent's utility in real time, or time discounting. In the class of negotiation with some constraints, the effective automated negotiation agents can adjust their behavior depending on the characteristics of their opponents and negotiation scenarios. Recently, the attention of this study has focused on the interleaving learning with negotiation strategies from the past negotiation sessions. By analyzing the past negotiation sessions, agents can estimate the opponent's utility function based on exchanging bids. In this article, we propose a negotiation strategy that estimates the opponent's strategies based on the past negotiation sessions. Our agent tries to compromise to the estimated maximum utility of the opponent by the end of the negotiation. In addition, our agent can adjust the speed of compromise by judging the opponent's Thomas–Kilmann conflict mode and search for the Pareto frontier using past negotiation sessions. In the experiments, we demonstrate that the proposed agent has better outcomes and greater search technique for the Pareto frontier than existing agents in the linear and nonlinear utility functions.     

A TWO‐STAGE WIN–WIN MULTIATTRIBUTE NEGOTIATION MODEL: OPTIMIZATION AND THEN CONCESSION

Many automated negotiation models have been developed to solve the conflict in many distributed computational systems. However, the problem of finding win–win outcome in multiattribute negotiation has not been tackled well. To address this issue, based on an evolutionary method of multiobjective optimization, this paper presents a negotiation model that can find win–win solutions of multiple attributes, but needs not to reveal negotiating agents’ private utility functions to their opponents or a third‐party mediator. Moreover, we also equip our agents with a general type of utility functions of interdependent multiattributes, which captures human intuitions well. In addition, we also develop a novel time‐dependent concession strategy model, which can help both sides find a final agreement among a set of win–win ones. Finally, lots of experiments confirm that our negotiation model outperforms the existing models developed recently. And the experiments also show our model is stable and efficient in finding fair win–win outcomes, which is seldom solved in the existing models.     

A REGION‐BASED MULTI‐ISSUE NEGOTIATION PROTOCOL FOR NONMONOTONIC UTILITY SPACES

Nonmonotonic utility spaces are found in multi‐issue negotiations where the preferences on the issues yield multiple local optima. These negotiations are specially challenging because of the inherent complexity of the search space and the difficulty of learning the opponent’s preferences. Most current solutions successfully address moderately complex preference scenarios, while solutions intended to operate in highly complex spaces are constrained by very specific preference structures. To overcome these problems, we propose the Region‐Based Multi‐issue Negotiation Protocol (RBNP) for bilateral automated negotiation. RBNP is built upon a nonmediated recursive bargaining mechanism which efficiently modulates a region‐based joint exploration of the solution space. We empirically show that RBNP produces outcomes close to the Pareto frontier in reasonable negotiation times, and show that it provides a significantly better performance when compared to a generic Similarity‐Based Multi‐issue Negotiation Protocol (SBNP), which has been successfully used in many negotiation models. We have paid attention to the strategic issues, proposing and evaluating several concession mechanisms, and analyzing the equilibrium conditions. Results suggest that RBNP may be used as a basis to develop negotiation mechanisms in nonmonotonic utility spaces.     

Agent-based joint model of residential location choice and real estate price for land use and transport model

Residential location choice (RLC) and real estate price (REP) models are traditional and key components of land use and transport model. In this study, an agent-based joint model of RLC and REP (RLC–REP model) was proposed for SelfSim, an agent-based dynamic evolution of land use and transport model. The RLC–REP model is capable of simulating the negotiation between the active household agents (buyers) and owner agents (sellers) using agent-based modeling. In particular, both utility maximization theory and prospect theory were used to develop a utility function to simulate the location choice behavior of active household agents. The utility function incorporates only two variables: house price and accessibility. The latter variable is calculated using MATSim, an activity-based model. The asking price behavior of owner agents is based on three specific rules. The residential location choices of household agents and house prices can be obtained by negotiation. Finally, genetic algorithm was used to estimate the parameters of the RLC–REP model. The calibrated model was tested in Baoding, a medium-sized city in China, and historical validation was performed to assess its performance. The results suggest that the forecasting ability of the RLC–REP model in terms of real estate price is satisfactory.     

多机服务器任务调度的经济学方法

本文针对多机服务器提出了一种任务调度的经济学方法 :以一般均衡理论为基础 ,依靠价格机制实现资源的优化分配 ;讨论了多机服务器的系统模型、任务的聚类和效用函数、经济学模型及均衡状态的最优性 ;最后通过模拟实验验证了经济学方法的有效性     

超立方体多处理机系统中基于扩展最优通路矩阵的容错路由

该文在高峰等文章的基础上，提出了针对超立方体结构多处理机系统的扩展最优通路矩阵（Extended Optimal Path Matrices,EOPMs）的概念，并给出了一个建立EIPMs的算法和基于EOPMs的容错路由算法，证明了基于EOPMs的容错路由算法是基于扩展安全向量（ESVs）^[13]和基于最优通路矩阵（OPMs)^[14]容错路由算法的扩展，与原文相比，该算法的存储开销与OPMs,相同，但记录的最优通路的信息，包含了原文所记录的最优通路的信息，使搜索最优通路的能力比它们有进一步的提高。     

具有多优先级多服务网络的激励价格控制

运用Stackelberg对策中的激励原理,研究具有多优先级的多服务网络系统的价控问题。提出了具有管理者的用户两优先级的激励模型,给出了确定激励参数的方法。将此方法扩展到多优先级的情形,推导出互联激励参数矩阵。通过数值例子说明了激励价格策略的有效性。     

Addressing stability issues in mediated complex contract negotiations for constraint-based, non-monotonic utility spaces

Negotiating contracts with multiple interdependent issues may yield non- monotonic, highly uncorrelated preference spaces for the participating agents. These scenarios are specially challenging because the complexity of the agents’ utility functions makes traditional negotiation mechanisms not applicable. There is a number of recent research lines addressing complex negotiations in uncorrelated utility spaces. However, most of them focus on overcoming the problems imposed by the complexity of the scenario, without analyzing the potential consequences of the strategic behavior of the negotiating agents in the models they propose. Analyzing the dynamics of the negotiation process when agents with different strategies interact is necessary to apply these models to real, competitive environments. Specially problematic are high price of anarchy situations, which imply that individual rationality drives the agents towards strategies which yield low individual and social welfares. In scenarios involving highly uncorrelated utility spaces, “low social welfare” usually means that the negotiations fail, and therefore high price of anarchy situations should be avoided in the negotiation mechanisms. In our previous work, we proposed an auction-based negotiation model designed for negotiations about complex contracts when highly uncorrelated, constraint-based utility spaces are involved. This paper performs a strategy analysis of this model, revealing that the approach raises stability concerns, leading to situations with a high (or even infinite) price of anarchy. In addition, a set of techniques to solve this problem are proposed, and an experimental evaluation is performed to validate the adequacy of the proposed approaches to improve the strategic stability of the negotiation process. Finally, incentive-compatibility of the model is studied.