一个改进的理性Agent-BDI模型

利用一种新的可能世界语义,在Ｒａｏ和Ｇｅｏｒｇｅｆｆ的基于分支时间可能世界模型的ＢＤＩ形式化的基础上,得到一个改进的ＢＩＤ模型。与Ｒａｏ和Ｇｅｏｒｇｅｆｆ的ＢＤＩ模型以及大多数基于可能世界的形式化相比,不存在逻辑全知问题和除等价情况外的副作用问题。     

Design and implementation of a multiagent stock trading system

Stock trading is one of the key items in an economy and estimating its behavior and taking the best decision in it are among the most challenging issues. Solutions based on intelligent agent systems are proposed to cope with those challenges. Agents in a multiagent system (MAS) can share a common goal or they can pursue their own interests. That nature of MASs exactly fits the requirements of a free market economy. Although existing studies include noteworthy proposals on agent‐based market simulation and researchers discuss theoretical design issues of agent‐based stock exchange systems, unfortunately only a very few of the studies consider exact development and implementation of multiagent stock trading systems within the software engineering perspective and guides to the software engineers for constructing such software systems starting from scratch. To fill this gap, in this paper, we discuss the development of a multiagent‐based stock trading system by taking into consideration software design according to a well‐defined agent oriented software engineering methodology and implementation with a widely‐used MAS software development framework. Each participant in the system is first designed as belief–desire–intention agents with their facts, goals, and plans, and then belief–desire–intention reasoning and behavioral structure of the designed agents are implemented. Lessons learned during design and development within the software engineering perspective and evaluation of the implemented multiagent stock exchange system are also reported. Copyright © 2011 John Wiley & Sons, Ltd.     

基于非单调逻辑的自适应BDI模型

由于Agent直接与现实世界发生交互作用，设计者难以事先预料所有可能出现的环境状况并一一规定恰当的处理方法，Agent往往不能产生恰当的行为，从而可能导致问题求解失败。本文结合BDI模型和非单调逻辑的优点，引入了可能信念概念和信念维护算子，表达了Agent和动态环境之阃的互动关系;引入Agent价值概念和行为规划算子，表达了期 期望和意图之间的动态约束关系，很好地解决了Agent在非预期环境中的适应性问题。     

一种理性Agent的BDI模型

该文通过引入假设信念,解释愿望和意图在Agent思维状态的认知方面的含义,进而定义愿望和意图,并引入规划,建立理性Agent的动态BDI模型.与Cohen和Levesque,Rao和Georgeff,Konolige和Pollack等人的工作相比,克服了对信念、愿望和意图的反直观解释问题,解决了关于愿望和意图的无为而治和副作用问题,强调了愿望的激发与维护作用,表达了信念、愿望和意图三者间的动态约束与激发关系.     

A high-level architecture for believable social agents

The creation of virtual humans capable of behaving and interacting realistically with each other requires the development of autonomous believable social agents. Standard goal-oriented approaches are not well suited to it because they don't take into account important characteristics identified by the social sciences. This paper tackles the issue of a general social reasoning mechanism, discussing its basic functional requirements using a sociological perspective, and proposing a high-level architecture based on Roles, Norms, Values and Types.     

一种基于信念-期望-意图和效用的社会承诺机制

在多智能体系统中,为完成问题求解智能体之间需建立起社会承诺.文章将信念-期望-意图和效用理论结合起来,提出了一种社会承诺机制,保证了智能体行为的逻辑理性和决策理性.该文的工作将Rao&Georgeff的信念-期望-意图理论和S.Kraus的激励承包思想有机地结合起来,改进了Haddadi的社会承诺机制,为Castelfranchi的社会承诺提供了实现支持.     

BDI模型信念特性研究

计算的典型模型是BDI(belief, desire, intention),信念是Agent计算的重要属性.把信念拓展为知识性信念和可实现信念. Agent的知识性信念是指Agent当前具有或掌握的知识,具有知识的进化和继承特性. Agent的可实现信念是指当前不成立而在将来会成立的事情,是Agent被意识到的个性倾向和目标.用非标准世界的模态逻辑为形式化工具描述两种信念,将可能世界的可达关系作为认识的不同阶段和达到可实现信念的不同阶段,避免了“逻辑全知问题”和逻辑蕴涵的副作用问题.可实现信念满足KD公理,知识性信念满足KDT4公理.两种信念适合描述Agent的意识状态和意识模型.     

社会Agent的BDO模型

目前MAS中思维状态的研究趋势是在个体模型中加入社会思维属性,研究社会承诺、依赖、联合意图的推理关系。在BDI模型中,以意图为中心的观点不描述社会Agent。该文分析了以竭力为中心的Agent思维状态研究存在的问题,提出MAS的分层模型,并提出以信念、愿望和义务作为基本思维属性（简称BDO）来描述Agent的思维状态和社会属性,给出了BDO逻辑和语义模型,考虑了奖励、惩罚、承诺和承诺解除问题,并对队、组织、组织意图等现象给出了描述。该文力图更自然地描述社会性Agent的思维状态和群体概念,是对Rao和Georgeff提出的BDI模型的改进。最后通过一个例子说明了BDO的表达能力。进一步的工作包括建立更为完善的语义模型、结合各个思维属性的动态修正语义给出BDO Agent的动态模型以及给出基于BDO逻辑框架的Agent／MAS实现结构。     

Agent-BDI逻辑

阐述了Agent的形式化描述应该采用含有正规和非正规模态算子的混合模态逻辑为逻辑工具 的观点.建立了Agent-BDI逻辑的代表系统A-BI,讨论了它的语法和语义.特别是给出了非正 规模态算子基于Kripke标准可能世界的新的语义解释,证明了A-BI逻辑系统不但是可靠的, 而且是完备的.A-BI逻辑系统恰当地刻画了信念与意图的本质与内在联系,可作为Agent形式 化研究的逻辑工具.     

个性化的广告服务模型

与传统的广播电视、报纸等媒体相似，在因特网上，广告也扮演着重要的角色，成为网上主要的收入来源。Web广告与传统广告的重要区别在于Web广告更具个性化、针对性．我们可以应用智能体来进行个性化的广告决策。目前，已有一些基于知识的技术可用于智能体的建模和构建，但这种技术不能处理模糊的语言概念(如“年纪轻”)。因此，该文将另辟蹊径，采用模糊逻辑技术进行建模，进而实现个性化的广告服务．     

A preference processing model for cooperative agents

When multiple valid solutions are available to a problem, preferences can be used to indicate a choice. In a distributed system, such a preference-based solution can be produced autonomous agents cooperating together, but the attempt will lead to contention if the same resource is given preference by several user-agents. To resolve such contentions, this paper proposes a market-based payment scheme for selling and buying preferences by the contenders, in which the best solution is defined as the one where as many preferences as theoretically possible are globally met. After exploring the nature of preference, the paper develops a preference processing model based on the market based scheme, and presents a theoretical performance model to verify the correctness of the processing model. This verification is provided by a simulation study of the processing model. For the simulation study, a manufacturing environment is conjectured, where a set of tasks are resolved into subtasks by coordinator agents, and then these subtasks are allocated to assembler agents through cooperation and negotiation, in which preferred resources are exchanged against payments. The study shows that our agent based strategy not only produces convergence on the total preference value for the whole system, but also reaches that final value irrespective of the initial orderof subtask allocation to the assemblers.     

A legal analysis of human and electronic agents

Currently, electronic agents are being designed and implemented that, unprecedentedly, will be capable of performing legally binding actions. These advances necessitate a thorough treatment of their legal consequences. In our paper, we first demonstrate that electronic agents behave structurally similar to human agents. Then we study how declarations of intention stated by an electronic agent are related to ordinary declarations of intention given by natural persons or legal entities, and also how the actions of electronic agents in this respect have to be classified under German law. We discuss four different approaches of classifying agent declarations. As one of these, we propose the concept of an electronic person (i.e., agents with limited liability), enrolment of agents into an agent register, and agent liability funds as means to serve the needs of all contracting parties.     

Exploring Trading Strategies and Their Effects in the Foreign Exchange Market

One of the most critical issues that developers face in developing automatic systems for electronic markets is that of endowing the agents with appropriate trading strategies. In this article, we examine the problem in the foreign exchange (FX) market, and we use an agent‐based market simulation to examine which trading strategies lead to market states in which the stylized facts (statistical properties) of the simulation match those of the FX market transactions data. Our goal is to explore the emergence of the stylized facts, when the simulated market is populated with agents using different strategies: a variation of the zero intelligence with a constraint strategy, the zero‐intelligence directional‐change event strategy, and a genetic programming‐based strategy. A series of experiments were conducted, and the results were compared with those of a high‐frequency FX transaction data set. Our results show that the zero‐intelligence directional‐change event agents best reproduce and explain the properties observed in the FX market transactions data. Our study suggests that the observed stylized facts could be the result of introducing a threshold that triggers the agents to respond to periodic patterns in the price time series. The results can be used to develop decision support systems for the FX market.     

Modeling the High‐Frequency FX Market: An Agent‐Based Approach

The development of computational intelligence‐based strategies for electronic markets has been the focus of intense research. To be able to design efficient and effective automated trading strategies, one first needs to understand the workings of the market, the strategies that traders use, and their interactions as well as the patterns emerging as a result of these interactions. In this article, we develop an agent‐based model of the foreign exchange (FX) market, which is the market for the buying and selling of currencies. Our agent‐based model of the FX market comprises heterogeneous trading agents that employ a strategy that identifies and responds to periodic patterns in the price time series. We use the agent‐based model of the FX market to undertake a systematic exploration of its constituent elements and their impact on the stylized facts (statistical patterns) of transactions data. This enables us to identify a set of sufficient conditions that result in the emergence of the stylized facts similarly to the real market data, and formulate a model that closely approximates the stylized facts. We use a unique high‐frequency data set of historical transactions data that enables us to run multiple simulation runs and validate our approach and draw comparisons and conclusions for each market setting.     

基于社会网络的信任模型研究

研究了社会网络的原理以及现有信任模型的研究现状,并在此基础上结合网络交易和社会网络的特点,考虑了时间带来的信任衰减、交易风险等级、关系紧密程度等因素,建立了基于社会网络的互联网信任模型,通过计算结点间的信任值来衡量信任程度,仿真实验表明该模型能有效地识别出自夸点,能够防止通过小额交易积累信任值,之后进行大额交易欺骗的行为。仿真结果表明,该模型具有可行性。     

具有可信度的主体信念

本文提出了一种基于可信度逻辑的主体信念程度描述方法，这种方法通过定义信念的可信度描述主体信念的不确定性，允许相互矛盾的主体信念同时存在，并给出了可信度的计算方法与推理规则。信念修正和更新时，根据主体不同的性格采取不同的选择倾向，本文提出的“必要时修正”方法具有很高的效率和实用性。本文选择基于区间的时间逻逻辑描述主体信念中的时间概念，为涉及到大量时间段行为与操作的应用提供了一个新的信念逻辑描述方法。     

A logic-based environment for reactive agents in intelligent CAD systems

This paper is an evolution of a previous article by the authors[1] (Bento, J. P., Feijó, B., Lloyd-Smith, D., Computers and Structures, 1977, 63(5), 1015–1032) motivated by the need to provide computational support to an agent-based implementation of design processes. It presents a new programming environment to support the development of CAD systems based on a hybrid agent architecture in which the symbolic reasoning is carried out by first-order logic. The reactive behaviour of the agents can be achieved through a number of characteristics proposed for the object-oriented environment. This environment is also a general proposal for representing engineering design knowledge in which logic is integrated into an object-oriented paradigm. © 1998 Published by Elsevier Science Limited. All rights reserved.     

A New Criterion for Comparing Fuzzy Logics for Uncertain Reasoning

A new criterion is introduced for judging the suitability of various fuzzy logics for practical uncertain reasoning in a probabilistic world and the relationship of this criterion to several established criteria, and its consequences for truth functional belief, are investigated.