Reasoning situated in time I: basic concepts*

Abstract

The needs of a real-time reasoner situated in an environment may make it appropriate to view error-correction and non-monotonicity as much the same thing. This has led us to formulate situated (or step) logic, an approach to reasoning in which the formalism has a kind of real-time self-reference that affects the course of deduction itself. Here we seek to motivate this as a useful vehicle for exploring certain issues in commonsense reasoning. In particular, a chief drawback of more traditional logics is avoided: from a contradiction we do not have all wffs swamping the (growing) conclusion set. Rather, we seek potentially inconsistent, but nevertheless useful, logics where the real-time self-referential feature allows a direct contradiction to be spotted and corrective action taken, as part of the same system of reasoning. Some specific inference mechanisms for real-time default reasoning are suggested, notably a form of introspection relevant to default reasoning. Special treatment of ‘now’ and of contradictions are the main technical devices here. We illustrate this with a computer-implemented real time solution to R. Moore's Brother Problem.     

Sensory—motor coordination: The metaphor and beyond

Any agent in the real world has to be able to make distinctions between different types of objects, i.e. it must have the competence of categorization. In mobile agents, there is a large variation in proximal sensory stimulation originating from the same object. Therefore, categorization behavior is hard to achieve, and the successes in the past in solving this problem have been limited. In this paper it is proposed that the problem of categorization in the real world is significantly simplified if it is viewed as one of sensory—motor coordination, rather than one of information processing happening “on the input side”. A series of models are presented to illustrate the approach. It is concluded that we should consider replacing the metaphor of information processing for intelligent systems by the one of sensory-motor coordination. However, the principle of sensory-motor coordination is more than a metaphor. It offers concrete mechanisms for putting agents to work in the real world. These ideas are illustrated with a series of experiments.     

ANGLE: An autonomous, normative and guidable agent with changing knowledge

Some emerging computing systems (especially autonomic computing systems) raise several challenges to autonomous agents, including (1) how to reflect the dynamics of business requirements, (2) how to coordinate with external agents with sufficient level of security and predictability, and (3) how to perform reasoning with dynamic and incomplete knowledge, including both informational knowledge (observations) and motivational knowledge (for example, policy rules and contract rules). On the basis of defeasible logic and argumentation, this paper proposes an autonomous, normative and guidable agent model, called ANGLE, to cope with these challenges. This agent is established by combining beliefs-desires-intentions (BDI) architecture with policy-based method and the mechanism of contract-based coordination. Its architecture, knowledge representation, as well as reasoning and decision-making, are presented in this paper. ANGLE is characteristic of the following three aspects. First, both its motivational knowledge and informational knowledge are changeable, and allowed to be incomplete, inconsistent/conflicting. Second, its knowledge is represented in terms of extended defeasible logic with modal operators. Different from the existing defeasible theories, its theories (including belief theory, goal theory and intention theory) are dynamic (called dynamic theories), reflecting the variations of observations and external motivational knowledge. Third, its reasoning and decision-making are based on argumentation. Due to the dynamics of underlying theories, argument construction is not a monotonic process, which is different from the existing argumentation framework where arguments are constructed incrementally.     

《网络安全》教学中学生自主学习能力的培养

针对《网络安全》课程的特点,为了激发学生的学习兴趣和创新精神,根据教学实践经验提出了《网络安全》教学中培养学生自主学习能力的相关策略。实践证明,在教学过程中加强学生自主学习能力的培养能达到更好的教学效果。     

基于常识的亲属关系推理模型

常识知识的研究与发展得到了人工智能界的很大重视。文章建立了一个基于常识的人物亲属关系推理模型,研究了亲属关系常识以及人物信息的表示与存储。此外,对实际所要解决的问题进行了总结。     

浅谈利用语音室进行学生英语学习自我评价系统

学生的自我评价是形成性评价的主要组成部分。通过自我评价．可以培养学生的自主学习意识．发展学习策略．对于塑造学生的终身学习和创新能力都有着重要的意义。     

Responding efficiently to relevant stimuli using an emotion-based agent architecture

It is widely accepted that one important role of emotions consists in providing a mechanism for adequate and efficient response to relevant stimuli. In this paper we propose a methodology for implementing such a mechanism, based on a previously presented emotion-based agent model. This agent model is biologically inspired in the emotion mechanisms found in the brain, following recent neurophysiological research. This model is founded on two principles: (1) stimuli is represented internally by two representations with different degrees of complexity and accuracy, and (2) the matching of these representations is implemented by a distance function. The mechanism considered in this paper amounts to matching the current stimulus the agent is perceiving with its past experience. This paper addresses a twofold strategy for optimizing the efficiency and accuracy of this mechanism. The first one consists in adapting the distance function employed in one of the representations, while the second one has the goal of upgrading that representation with new relevant features. Techniques borrowed from nonmetric multidimensional scaling are used to approach these goals.     

How does a box work? A study in the qualitative dynamics of solid objects

This paper is an in-depth study of qualitative physical reasoning about one particular scenario: using a box to carry a collection of objects from one place to another. Specifically we consider the plan, plan1 “Load objects uCargo into box oBox one by one; carry oBox from location l1 to location l2”. We present qualitative constraints on the shape, starting position, and material properties of uCargo and oBox and on the characteristics of the motion that suffice to make it virtually certain that plan1 can be successfully executed. We develop a theory, consisting mostly of first-order statements together with two default rules, that supports an inference of the form “If conditions XYZ hold, and the agent attempts to carry out plan1 then presumably he will succeed”. Our theory is elaboration tolerant in the sense that carrying out the analogous inference for carrying objects in boxes with lids, in boxes with small holes, or on trays can reuse much of the same knowledge. The theory integrates reasoning about continuous time, Euclidean space, commonsense dynamics of solid objects, and semantics of partially specified plans.     

计算机语言类课程教学法研究与实践

C、C++和Java等宿主语言是计算机专业必修的课程。本文指出了语言课程的教与学中存在的问题,并结合软件开发方法对课程教学法作了积极地探索。采用启发式教学、探究式教学,激发学生的学习潜能,使之掌握编程思维和方法,对提高他们的自主学习能力、培养他们的创新精神有着积极的作用。     

基于行动导向的网络课程研究与建设

行动导向是目前职业教育先进的教学模式,很适合职业教育.网络课程是目前很多高校比较流行的教学科目,将二者结合用于计算机教学,可以很好地促进计算机教学,也可以使得学生能充分实现自主学习,从而达到职业教育的教学目的.     

面向常识的时间推理

常识和时间推理是人工智能研究的两个主要课题.Allen等人提出的时间推理缺少时间点、时区和时距的统一表示;过分考虑计算,缺少规则推理;求解算法难以应用于多Agent环境并且没有考虑常识不一致性.该文提出一种时间信息表示网络,分析了约束之间的推导规则,给出了常识时间问题的多Agent合作满足弱路径一致性的求解方法.该文的工作改进了Meiri,Wetprasit和Sattar等人的工作,为时间推理结合常识特性和适应多Agent合作环境提供了可行的方案.     

Event calculus and temporal action logics compared

We compare the event calculus and temporal action logics (TAL), two formalisms for reasoning about action and change. We prove that, if the formalisms are restricted to integer time, inertial fluents, and relational fluents, and if TAL action type specifications are restricted to definite reassignment of a single fluent, then the formalisms are not equivalent. We argue that equivalence cannot be restored by using more general TAL action type specifications. We prove however that, if the formalisms are further restricted to single-step actions, then they are logically equivalent.     

《ASP动态网页设计》课程教学方法改革与实践

针对《ASP动态网页设计》这门课程在教学过程当中存在学生学习兴趣低、难度大、效果差等突出问题,采用《多元化教学模式》,通过树立多元化的教学目标,设置多元化的教学内容、应用多元化的教学方法,实施多元化的成绩考核体系,全面提高学生学习兴趣、自主学习能力和综合应用能力。通过两届学生实践,基本解决上述问题,获得良好的教学效果。     

互动式分层教学在中职计算机课程中应用初探

中职学校的计算机基础课是计算机专业基础课。旨在培养学生的自主操作能力和计算机素养。在网络教学平台下的辅助下如何让基础薄弱、学习速度较慢的学生“吃得了”．又让基础好、学得快的学生“吃得好”,并充分挖掘每个学生自身的学习潜力．提高学生的自主学习能力。根据以往教学经验就中职计算机基础课程如何实施分层教学做一些探讨。     

基于Web的C语言程序设计自主学习系统的设计与实现

讨论利用PHP、MySQL技术开发基于Web的C语言测试系统的关键技术,给出基于Web的测试系统的设计模型。本系统为学习C语言的师生提供一个网络平台,并丰富了C语言的教学手段。     

Source seeking with non-holonomic unicycle without position measurement and with tuning of forward velocity

We consider the problem of seeking the source of a scalar signal using an autonomous vehicle modeled as the non-holonomic unicycle and equipped with a sensor of that scalar signal but not possessing the capability to sense either the position of the source nor its own position. We assume that the signal field is the strongest at the source and decays away from it. The functional form of the field is not available to our vehicle. We employ extremum seeking to estimate the gradient of the field in real time and steer the vehicle towards the point where the gradient is zero (the maximum of the field, i.e., the location of the source). We employ periodic forward–backward movement of the unicycle (implementable with mobile robots and some underwater vehicles but not with aircraft), where the forward velocity has a tunable bias term, which is appropriately combined with extremum seeking to produce a net effect of “drifting” towards the source. In addition to simulation results we present a local convergence proof via averaging, which exhibits a delicate periodic structure with two sinusoids of different frequencies—one related to the angular velocity of the unicycle and the other related to the probing frequency of extremum seeking.     

浅谈德国“自主学习”式职业教育

通过对德国的考察和分析,本文主要讨论了德国职业教育中"自主式学习"的教学环境、教学组织、课程考核。教师通过能力矩阵对学生进行分析,布置教学任务,进行引导与组织,提高学生学习兴趣,较好完成教学效果。