一种基于主体可信度的联合辩论框架

辩论框架是计算机利用辩论机制来解决实际问题的基础,如商务谈判、法律纠纷和劳动争议等。传统的辩论框架对辩论机制和论证方法作了具体的形式化描述,但忽略了辩论主体及其对辩论结果影响的描述,而且在辩论过程中一个论点通常需要多个论据的联合论证。针对以上问题,在传统辩论框架的基础上,提出了一种基于主体可信度的联合辩论框架(STUAF)。首先引入了辩论主体的概念,并对观点和论据之间的联合论证进行形式化定义;其次给出了完整的框架结构和语义描述,证明了该辩论框架满足Dunk提出的标准辩论框架的基本定理;然后结合辩论树给出了语义计算的算法;最后给出一个具体的应用实例,实例分析表明S I'UAF及其语义算法是有效的。     

基于可信度的辩论模型及争议评价算法

辩论是智能主体间为了消除分歧的一种基于言语的交互行为.由于知识的局限性,争议以及争议内部的陈述通常存在不确定性,因此在对辩论进行建模时需要考虑不确定信息处理问题.提出一种基于可信度的辩论模型（CFA）,该模型将争议表示为由若干前提和一个结论组成的可废止规则,并用对话树描述辩论推演过程.为了表示不确定性推理,引入可信度模型,将争议前提的不确定性和争议之间的攻击强度统一用可信度因子表示.在此基础上,提出计算陈述可信度的争议评价算法,并通过设定可信度阈值确定陈述的可接受性,得出最终辩论结果.最后,用一个实例说明该方法的有效性.该模型可以有效处理不确定信息条件下辩论推理过程,其辩论算法建立在数值计算基础之上,所得出的可接受陈述集在给定可信度阈值条件下是唯一的,可以克服Dung 的抽象辩论框架中扩充语义的不足.     

Agent口碑辩论模型研究

基于辩论的Agent谈判能提高Agent在动态环境下的谈判效率,保证谈判效果。口碑则能强化辩论效果。为保证模型的整体性,将对Agent口碑辩论模型的阐述分为描述和评价两个部分;对口碑进行分类,结合形式化理论,提出Agent口碑辩论模型的描述部分;提出口碑辩论力度的概念,并对其进行量化,提出Agent口碑辩论模型的评价部分;最后通过算例对模型进行验证。     

基于辩论的多agent商务谈判产生机制研究*

针对辩论的产生是基于辩论的谈判中agent决策机制的核心问题,提出了一个基于冲突解决和辩论分类的辩论产生机制,该机制包括谈判agent的多目标优化模型、谈判过程控制的状态机协议以及基于冲突解决的辩论生成策略等。最后通过一对一商务谈判原型系统验证了所提模型、协议和策略的有效性。     

基于动态规划的优先语义扩充求解算法

抽象辩论框架中的优先语义是判断争议可接受程度的最重要语义。现有优先扩充求解方法多用标记映射求解,依赖于标记的定义、转换规则、相邻争议的标记。算法每次迭代会产生一个新的抽象辩论框架导致时间、空间复杂度较高。提出一种基于动态规划的优先扩充算法,在动态规划中加入争议可接受性判断,求出辩论框架中极大可容许集得到优先扩充。在基于随机抽象辩论框架与ICCMA提供的数据集进行实验,同Heureka、ArgSemSAT等算法进行对比。结果表明,求解相同数量的优先扩充,算法耗时较少,时间、空间复杂度有所降低。     

描述逻辑SHIOQ的时态扩展

分析描述逻辑时态扩展的优缺点,同时结合实际应用需求,将时间当作具体领域加入到描述逻辑中来处理,给出带时态扩展的描述逻辑SHIOQ（T）的形式化描述,并给出SHIOQ（T）中概念、关系和实例的描述形式以及它们的语义解释,从而方便地实现时态知识的表达和推理。     

辩论的理论模型及其算法研究

本文研究分布式人工智能背景下的辩论的理论模型及其算法,提出并建立了一个基于命题性知识的辩论的理论框架.在此框架下,我们给出了几个体现不同辩论策略的辩论算法,并对算法的正确性给出了理论证明.本文的研究可为分布式人工智能中多专家系统的辩论和意见综合提供参考,进一步的研究可望推进多专家联合系统的实用化进程.     

时态RDF扩展及其SPARQL查询语言

随着语义网的快速发展以及RDF框架（资源描述框架）的普遍应用,对含有时间信息的数据处理的需求越来越多,经典RDF模型由其本身结构特点缺乏表示和处理时间信息的能力,而且针对时态RDF的研究罕有得见。通过对经典RDF模型添加时间戳表示其时间维度,并对时态RDF图中的蕴含问题进行了讨论,根据SPARQL查询语言提出了完备的时态RDF查询语言Tsparql,并对提出的查询语言进行可行性以及性能进行了实验仿真。利用该时态RDF模型表示如股票、天气、新闻等具有时态特性的资源有优势,Tsparql对时态RDF进行查询具有良好的表达力和兼容性。     

基于区间代数的工作流模式的建模研究

在业务流程建模阶段,从时态角度采分析业务流程,有助于清楚地描述工作流.在对工作流模式以及其中包含的时态语义进行了深入研究之后,根据区间代数的语法,将工作流模式和区间代数结合起来,提出了一种新的用于工作流模式的时间约束建模方法.它不仅从时态角度扩展了工作流建模,明确描述了工作流模式中和时序有关的时态约束和依赖关系,并且能使工作流控制模式和形式化验证工具结合,从而有利于进一步从时态角度研究业务流程建模.     

A Reasoning Model Based on the Production of Acceptable Arguments

Argumentation is a reasoning model based on the construction of arguments and counter-arguments (or defeaters) followed by the selection of the most acceptable of them. In this paper, we refine the argumentation framework proposed by Dung by taking into account preference relations between arguments in order to integrate two complementary points of view on the concept of acceptability: acceptability based on the existence of direct counter-arguments and acceptability based on the existence of defenders. An argument is thus acceptable if it is preferred to its direct defeaters or if it is defended against its defeaters. This also refines previous works by Prakken and Sartor, by associating with each argument a notion of strength, while these authors embed preferences in the definition of the defeat relation. We propose a revised proof theory in terms of AND/OR trees, verifying if a given argument is acceptable, which better reflects the dialectical form of argumentation.     

分级论辩系统的逻辑研究

近年来,形式论证已逐渐成为人工智能领域的研究热点之一。自Dung于1995年提出抽象辩论框架起,学术界普遍认为论辩的核心任务是在各种基于外延的语义下对论点集进行评估,以确定其辩护状态。分级论辩系统(Graded Argumentation System,GAS)是对经典Dung型论辩系统(Dung-style Argumentation System,DAS)的推广,通过一般化DAS语义的两个核心性质,即无冲突性和可接受性,来提供更细化的论点状态概念。当前的论辩系统语义等效性研究主要集中在框架和论点层次上,可为其结构约简提供有力的保证。针对两个不同分级论辩系统中论点的语义等效问题,首先运用分级模态逻辑(Graded Modal Logic,GML)形式化分级论辩系统的片段,然后建立并证明了分级论辩系统基于外延的语义和GML公式之间的一一对应关系,最后定义分级互模拟关系并证明其蕴含分级论辩系统的4个重要的语义等价性。     

A logic of argumentation for specification and verification of abstract argumentation frameworks

In this paper, we propose a logic of argumentation for the specification and verification (LA4SV) of requirements on Dung??s abstract argumentation frameworks. We distinguish three kinds of decision problems for argumentation verification, called extension verification, framework verification, and specification verification respectively. For example, given a political requirement like ??if the argument to increase taxes is accepted, then the argument to increase services must be accepted too,?? we can either verify an extension of acceptable arguments, or all extensions of an argumentation framework, or all extensions of all argumentation frameworks satisfying a framework specification. We introduce the logic of argumentation verification to specify such requirements, and we represent the three verification problems of argumentation as model checking and theorem proving properties of the logic. Moreover, we recast the logic of argumentation verification in a modal framework, in order to express multiple extensions, and properties like transitivity and reflexivity of the attack relation. Finally, we introduce a logic of meta-argumentation where abstract argumentation is used to reason about abstract argumentation itself. We define the logic of meta-argumentation using the fibring methodology in such a way to represent attack relations not only among arguments but also among attacks. We show how to use this logic to verify the requirements of argumentation frameworks where higher-order attacks are allowed [A preliminary version of the logic of argumentation compliance was called the logic of abstract argumentation?(2005).]     

On Construction and Evaluation of Analogical Arguments for Persuasive Reasoning

ABSTRACT

Analogical reasoning is a complex process based on a comparison between two pairs of concepts or states of affairs (aka. the source and the target) for characterizing certain features from one to another. Arguments which employ this process to support their claims are called analogical arguments. Our goals are to study the structure and the computation for their defeasibility in light of the argumentation theory. Our proposed assumption-based argumentation with predicate similarity ABA^(p) framework can be seen as an extension of assumption-based argumentation framework (ABA), in which not only assumptions can be used but also similarity of predicates is used to support a claim. ABA ^(p) labels each argument tree with an analogical degree and different ways to aggregate numerical values are studied toward gullible/skeptical characteristics in agent reasoning. The acceptability of analogical arguments is evaluated w.r.t. the semantics of abstract argumentation. Finally, we demonstrate that ABA ^(p) captures the argumentation scheme for argument from analogy and provides an explanation when it is used for persuasion.     

LASAD: Flexible representations for computer-based collaborative argumentation

Teaching argumentation is challenging, and the factors of how to effectively support the acquisition of argumentation skills through technology are not fully explored yet. One of the key reasons for that is the lack of comparability between studies. In this article, we describe LASAD, a collaborative argumentation framework that can be flexibly parameterized. We illustrate the flexibility of the framework with respect to visualization, structural definitions and kind of cooperation. Using this framework, this paper presents an evaluation of the impact of using an argumentation system with different argument representations and with collaborative vs. individual use on the outcomes of scientific argumentation. We investigate which combinations of these factors produces the best results concerning argument production and learning outcomes. The results of this controlled lab study with 36 participants showed that the use of simple representational formats is superior compared to highly structured ones. Even though the latter encouraged the provision of additional non-given material, the former is less error-prone. A hypothesized structural guidance provided by more complex formats could not be confirmed. With respect to collaboration, the results highlight that arguing in groups lead to more cluttered argumentation maps, including a higher amount of duplicate elements. An expected peer-reviewing between group members did not occur. Yet, groups also tended to include more points-of-view in their arguments, leading to more elaborated argument maps.     

Reasoning about preferences in argumentation frameworks

The abstract nature of Dung's seminal theory of argumentation accounts for its widespread application as a general framework for various species of non-monotonic reasoning, and, more generally, reasoning in the presence of conflict. A Dung argumentation framework is instantiated by arguments and a binary conflict based attack relation, defined by some underlying logical theory. The justified arguments under different extensional semantics are then evaluated, and the claims of these arguments define the inferences of the underlying theory. To determine a unique set of justified arguments often requires a preference relation on arguments to determine the success of attacks between arguments. However, preference information is often itself defeasible, conflicting and so subject to argumentation. Hence, in this paper we extend Dung's theory to accommodate arguments that claim preferences between other arguments, thus incorporating meta-level argumentation based reasoning about preferences in the object level. We then define and study application of the full range of Dung's extensional semantics to the extended framework, and study special classes of the extended framework. The extended theory preserves the abstract nature of Dung's approach, thus aiming at a general framework for non-monotonic formalisms that accommodate defeasible reasoning about as well as with preference information. We illustrate by formalising argument based logic programming with defeasible priorities in the extended theory.     

Argumentation in the Semantic Web

In this article, we define ArgSciFF, a prototype operational argumentation framework to support dialogic argument exchange between Semantic Web services. ArgSciFF is based on the Sciff abductive-logic programming (ALP) framework. (Sciff is an abbreviation for "IFF with constraints for agent societies," referring to the "if and only if' proof procedure developed by Tze Ho Fung and Robert Kowal-ski.) In ArgSciFF, an intelligent agent can interact with a Web service and reason from the interaction result. The reasoning semantics is an argumentation semantics that views the interaction as a dialogue. The dialogue lets two parties exchange arguments and attack, challenge, and justify them on the basis of their knowledge. This format has the potential to overcome a well-known barrier to human users' adoption of IT solutions because it permits interaction that includes justified answers that can be reasoned about and rebutted.     

基于价值辩论框架的决策支持技术研究

在复杂、开放、不确定的环境中,决策者都面临着对行动方案进行论证与选择的难题.基于辩论的决策支持技术是近年来出现的不同于传统辅助决策理论的新方法,它使用论据辅助决策制定和解释决策的理由.首先总结分析了当前基于价值辩论框架的决策支持模型存在的不足与缺陷,提出了论据分类的思想,然后根据该思想设计了ArguDecision辩论...