基于Agent的分布式系统信任模型仿真

针对当前信任模型仿真缺乏理论支撑,仿真过程描述及建模步骤不规范的问题,将多Agent建模仿真方法应用于信任模型的仿真,建立信任模型Agent仿真过程框架.由信任模型微观机制入手,对个体Agent进行设计,建立Agent实体模型;针对信任模型中Agent之间的交互问题设计基于推荐网的Agent协作算法;在充分考虑系统宏观约束的情况下,建立微观Agent到宏观系统之间的联系.通过实例验证了该方法的有效性.     

一种校园虚拟实验网格资源成本策略研究

在网格计算环境下,许多任务的执行经常需要同时协同分配多个agent以满足性能需求.文中提出了一种新的基于理性multi-agent编组机制的agent协同工作方法.然后,设计了校园虚拟实验网格调度系统及理性Agent编组机制用于有效的资源协同分配.     

人工股票市场建模中基于机制的Agent模型研究

在基于Agent人工股票市场建模中,如何使Agent能够具有自适应性的学习与进化性,已经成为人工股票市场建模中的一个很重要的研究内容.本文在研究传统Agent结构的基础上,试图从一个从全新的角度看待Agent的的适应与进化属性,并将Agent的概念进一步引申和扩展,引入了机制的概念,将Agent看作是由其内部的基本机制相互作用而动态构建的机制,并详细阐述了基于机制的Agent建模框架及其具体的实现.     

Agent的意图模型

意图是Agent的一个不可缺少的意识属性,在决定理性Agent的行为时起着重要的作用.已经有了若干种基于正规模态逻辑的意图模型,但它们存在着严重的“逻辑全知”问题.该文阐明意图不是正规模态算子,并提出了另一种意图模型,它不存在“逻辑全知”问题和其他相关问题(例如,副作用问题等).这种意图模型与Konolige和Pollack的意图模型相比,比较简单、自然,且满足K公理和联合一致性原理,实际上,为非正规模态算子基于正规可能世界的语义表示提供了一种新的方法.     

一种带概率与效用算子的Agent形式化模型

形式化方法描述Agent时需要考虑信念的不确定性与决策的效用性要素.在经典Agent的BDI形式化模型基础上,定义了Agent形式化语言,引入概率算子与效用算子,提出了Agent形式化模型,在此模型中利用概率算子与效用算子对Agent的信念、愿望、意图与规划等意识属性进行了定义.该模型能满足Agent对逻辑理性、信念的不确定性与决策理性的要求.     

Agent的组织承诺和小组承诺

基于Agent组织的多Agent问题求解对降低求解难度和求解复杂性有重要意义.对Agent组织的研究主要集中在组织模型、组织规则、组织结构以及组织的形成和演化等方面,需要从组织中Agent的各种思维属性及其相互关系加以扩展.分析和定义了Agent组织中Agent的内部承诺和社会承诺、小组承诺和组织承诺,研究了基于承诺的Agent组织的形成机制以及Agent组织中承诺的性质,从而推广了关于Agent组织的研究.     

一种新的属性约简算法

属性约简是粗糙集理论中的一个核心问题,为了有效获取属性最小相对约简,提出了一种新的基于相对差异比较表的属性约简算法.该算法给出了一种将信息表转化为相对差异比较表的方法,且该方法对于不相容决策表也是可行的,进而就将求解最小属性约简问题转化为求解一个0-1整数规划问题,并分别采用一般求解规划问题的方法和遗传算法两种方法来求解这个0-1整数规划问题.实验结果证明该算法结合遗传算法能够更加快速有效地进行属性约简.     

移动Agent在0-1型整数规划问题中的应用研究

本文介绍了移动Agent的定义及其应用。然后,分析了传统的0-1型整数规划算法,在此基础上,提出了基于移动Agent的0-1型整数规划算法。这主要是利用移动Agent的并行计算的特点。利用Grasshop-per平台实现了该算法,与传统的算法相比,减少了计算时间。     

基于规范的Agent混合结构模型研究

随着管理问题复杂性不断提高,计算实验方法应运而生。Agent作为计算实验方法中的主体,其模型构建的合理与否直接影响到仿真系统的实现与运行。通过研究Agent概念、特点以及已有Agent模型,结合管理科学、规范和计算实验相关理论,提出一种基于规范的Agent混合结构模型,并给出Agent的基类设计。最后,运用Swarm平台对一个实际案例进行仿真。仿真结果证明,该Agent模型具有可行性,适合于管理科学领域计算实验方法中的多Agent建模。     

考虑学习效应的单人作业车间调度算法

单人负责多台机器的单一工序作业车间场景中,工人由于重复操作机器而产生学习效应.针对考虑依赖工件位置学习效应的单人单工序作业车间最小化最大完工时间的调度问题,建立一种混合整数规划模型.为解决该问题,设计一个考虑学习效应的贪婪算子,利用该算子构造两种贪婪算法,并提出一种基于贪婪的模拟退火算法.为衡量混合整数规划模型、贪婪算法和基于贪婪的模拟退火算法的性能,设计两种规模问题的数据实验.通过实验得出:现代混合整数规划模型求解器可以解决机器数量和工件总数量乘积小于75的小规模问题;基于贪婪的模拟退火算法求解此问题具有有效性,适用于各种规模的问题;间隔插入贪婪算法解决此问题速度较快,效果良好,可以应用于需要快速求解的场景.     

On Social Constraints for Rational Agents

We define and study social constraints for rational agents. Our work is complementary to work on mechanism design in economics and Distributed Artificial Intelligence, as well as to work on artificial social systems. In our setting agents are rational but obey social laws that are imposed by the system's designer. Agents can be obliged to obey some social constraints, but not any constraint can serve as part of the social law. The main theme of our work is the study of settings where there are restrictions on the constraints that can serve as social laws. In such settings the designer should find social laws that can be imposed on the agents, and that will lead rational agents to satisfactory behavior. Our study is carried out in the context of zero‐sum and general‐sum games (with complete and with incomplete information) in extensive form.     

Multiagent task allocation in social networks

This paper proposes a new variant of the task allocation problem, where the agents are connected in a social network and tasks arrive at the agents distributed over the network. We show that the complexity of this problem remains NP-complete. Moreover, it is not approximable within some factor. In contrast to this, we develop an efficient greedy algorithm for this problem. Our algorithm is completely distributed, and it assumes that agents have only local knowledge about tasks and resources. We conduct a broad set of experiments to evaluate the performance and scalability of the proposed algorithm in terms of solution quality and computation time. Three different types of networks, namely small-world, random and scale-free networks, are used to represent various social relationships among agents in realistic applications. The results demonstrate that our algorithm works well and also that it scales well to large-scale applications. In addition we consider the same problem in a setting where the agents holding the resources are self-interested. For this, we show how the optimal algorithm can be used to incentivize these agents to be truthful. However, the efficient greedy algorithm cannot be used in a truthful mechanism, therefore an alternative, cluster-based algorithm is proposed and evaluated.     

社会网络下分配众包任务的真实机制

众包平台上出现了越来越多的宏任务,而这些宏任务需要工人的专业技能和团队的集体贡献。社会网络为社会工作者之间的合作提供了一个可用的平台。事实上,很少有研究关注众包工人之间的社会网络。在社会网络下的众包任务分配问题是NP难问题,并且社会网络中会存在参与者为了提高自己的效用而谎报要价的情况,因此提出一种社会网络下分配众包任务的真实机制（TMC-SN）。在社会网络下的众包任务分配问题被模拟成一个拍卖,其中任务请求者是买家,工人是卖家,众包平台充当拍卖者。为了找出最合适的团队,TMC-SN从边际贡献和团队凝聚力两个方面来衡量工人对团队的适应性。理论分析证明,TMC-SN具有真实性、个体理性、预算平衡等经济属性。实验结果表明,TMC-SN在社会福利方面具有一定的优势,并且能够提升工人的效用。     

A Pricing Mechanism for Resource Management in Grid Computing

We consider the problem of efficient resource allocation in a grid computing environment. Grid computing is an emerging paradigm that allows the sharing of a large number of a heterogeneous set of resources. We propose an auction mechanism for decentralized resource allocation. The problem is modeled as a multistage stochastic programming problem. Convergence of the auction allocations to the social optimum is established. Numerical experiments illustrate the efficacy of the method.     

Signalling and obfuscation for congestion control

We aim to reduce the social cost of congestion in many smart city applications. In our model of congestion, agents interact over limited resources after receiving signals from a central agent that observes the state of congestion in real time. Under natural models of agent populations, we develop new signalling schemes and show that by introducing a non-trivial amount of uncertainty in the signals, we reduce the social cost of congestion, i.e., improve social welfare. The signalling schemes are efficient in terms of both communication and computation, and are consistent with past observations of the congestion. Moreover, the resulting population dynamics converge under reasonable assumptions.     

社会网络下分配众包任务的真实机制

众包平台上出现了越来越多的宏任务，而这些宏任务需要工人的专业技能和团队的集体贡献。社会网络为社会工作者之间的合作提供了一个可用的平台。事实上，很少有研究关注众包工人之间的社会网络。在社会网络下的众包任务分配问题是NP难问题，并且社会网络中会存在参与者为了提高自己的效用而谎报要价的情况，因此提出一种社会网络下分配众包任务的真实机制（TMC-SN）。在社会网络下的众包任务分配问题被模拟成一个拍卖，其中任务请求者是买家，工人是卖家，众包平台充当拍卖者。为了找出最合适的团队，TMC-SN从边际贡献和团队凝聚力两个方面来衡量工人对团队的适应性。理论分析证明，TMC-SN具有真实性、个体理性、预算平衡等经济属性。实验结果表明，TMC-SN在社会福利方面具有一定的优势，并且能够提升工人的效用。     

DAS模式下基于密文分组索引的完整性验证

目前关于DAS模式下的全概率完整性验证方法主要是建立在明文数据上,并没有建立在密文数据上的完整性验证方法。提出一种建立在密文数据上的适用于动态数据库的完整性验证方法。分组索引是在DAS模式下的一种高效的密文索引,在密文数据分组索引的基础上,提出利用无碰撞增量式哈希生成完整性验证信息的方法。这是一种验证速度快(可并行计算)、维护代价小(对于增删改操作可增量式维护)的全概率验证方法,适用于动态数据库中完整性的验证。     

Properness defects of projection and minimal discriminant variety

The problem of describing the solutions of a polynomial system appears in many different fields such as robotic, control theory, etc. When the system depends on parameters, its minimal discriminant variety is the set of parameter values around which the roots of the system cannot be expressed as a continuous function of the parameters.In particular, an important component of the minimal discriminant variety is the set of properness defects. This article presents a method efficient in practice and in theory to compute the non-properness set of a projection mapping, by reducing the problem to a problem of variable elimination. We also present a reduction of the computation of the minimal discriminant variety to the computation of the non-properness set of a projection mapping. This result allows us to deduce a bound on the degree and the time computation of the minimal discriminant variety of a parametric system under some assumptions.     

Optimal sensor activation for diagnosing discrete event systems

The problem of dynamic sensor activation for event diagnosis in partially observed discrete event systems is considered. Diagnostic agents are able to activate sensors dynamically during the evolution of the system. Sensor activation policies for diagnostic agents are functions that determine which sensors are to be activated after the occurrence of a trace of events. The sensor activation policy must satisfy the property of diagnosability of centralized systems or codiagnosability of decentralized systems. A policy is said to be minimal if there is no other policy, with strictly less sensor activation, that achieves diagnosability or codiagnosability. To compute minimal policies, we propose language partition methods that lead to efficient computational algorithms. Specifically, we define “window-based” language partitions for scalable algorithms to compute minimal policies. By refining partitions, one is able to refine the solution space over which minimal solutions are computed at the expense of more computation. Thus a compromise can be achieved between fineness of solution and complexity of computation.     

Social welfare maximization in participatory smartphone sensing

Participatory smartphone sensing has lately become more and more popular as a new paradigm for performing large-scale sensing, in which each smartphone contributes its sensed data for a collaborative sensing application. Most existing studies consider that smartphone users are strictly strategic and completely rational, which try to maximize their own payoffs. A number of incentive mechanisms are designed to encourage smartphone users to participate, which can achieve only suboptimal system performance. However, few existing studies can maximize a system-wide objective which takes both the platform and smartphone users into account. This paper focuses on the crucial problem of maximizing the system-wide performance or social welfare for a participatory smartphone sensing system. There are two great challenges. First, the social welfare maximization cannot be realized on the platform side because the cost of each user is private and unknown to the platform in reality. Second, the participatory sensing system is a large-scale real-time system due to the huge number of smartphone users who are geo-distributed in the whole world. A price-based decomposition framework is proposed in our previous work (Liu and Zhu, 2013), in which the platform provides a unit price for the sensing time spent by each user and the users return the sensing time via maximizing the monetary reward. This pricing framework is an effective incentive mechanism as users are motivated to participate for monetary rewards from the platform. In this paper, we propose two distributed solutions, which protect users’ privacy and achieve optimal social welfare. The first solution is designed based on the Lagrangian dual decomposition. A poplar iterative gradient algorithm is used to converge to the optimal value. Moreover, this distributed method is interpreted by our pricing framework. In the second solution, we first equivalently convert the original problem to an optimal pricing problem. Then, a distributed solution under the pricing framework via an efficient price-updating algorithm is proposed. Experimental results show that both two distributed solutions can achieve the maximum social welfare of a participatory smartphone system.