An observer-canonical state-representation for a system of linear variable difference equations

This short paper presents a technique to convert a well-formed system of linear variable difference equations to a corresponding system of state equations. The technique applies to both causal and noncausal systems. The resulting state-representation is in the observer version of the Luenberger canonical form.     

Concurrency and recovery for index trees

Although many suggestions have been made for concurrency in B-trees, few of these have considered recovery as well. We describe an approach which provides high concurrency while preserving well-formed trees across system crashes. Our approach works for a class of index trees that is a generalization of the B-tree. This class includes some multi-attribute indexes and temporal indexes. Structural changes in an index tree are decomposed into a sequence of atomic actions, each one leaving the tree well-formed and each working on a separate level of the tree. All atomic actions on levels of the tree above the leaf level are independent of database transactions, and so are of short duration. Incomplete structural changes are detected in normal operations and trigger completion. Edited by A. Reuter. Received August 1995 / accepted July 1996     

A comparison between Hankel norms and induced system norms

A general definition is formulated for the Hankel norms as the induced norms of a strictly proper stable linear time-invariant (LTI) system mapping vector-valued L^p-past inputs to vector-valued L^q-future outputs. Some Hankel norms are derived by the maximum principle and duality. A property termed the system integral invariance is introduced by the derivation of those Hankel norms. Furthermore, the norm-induced initial conditions and the comparison between the Hankel norms and the induced system norms are also presented     

形式背景下的学习路径与技能评估

在认知学习过程中,学习者可能学习并掌握某些技能,但知识状态却无法发生改变.在此情形下,根据学习者知识状态的改变不足以对其技能进行准确评估,因此,文中基于技能函数,运用形式概念分析的方法寻找学习路径并进行技能评估.首先,介绍后继状态、有效技能和良好技能函数的概念.然后,基于形式背景,在两种情形下讨论技能函数满足良好性的条件,得到满足良好性条件下可进行逐步有效学习和有效评估的结果,并设计获取良好技能背景、良好技能函数及寻找学习路径的算法.最后,在两个数据集上进行实验分析,验证文中算法的有效性,并且得出如下结论:基于良好技能函数得到的学习路径图,不仅可有效指导学习者进行学习,还可根据学习者知识状态的变化评估其是否掌握相应的有效技能.     

A simulation of a solar energy system for heating water

This paper presents a simulation model for evaluating the economic viability of a solar system for heating water in an apartment building. The system consists of solar collectors and a back-up oil burner. The model determines the optimal number of collectors needed and the optimal method for connecting the collectors—in series or in parallel.

The simulation results show that the solar system for heating water is more economical as the life span of the system increases, as the prices of oil increase, and as the demand for hot water increases. Furthermore, connecting the collectors in series is more economical than connecting them in parallel.     

基于UML的软件体系结构的定量评估

软件体系结构是软件开发过程的关键制品,应该尽早地分析和评估其质量.目前研究的软件体系结构评估主要集中在基于场景的评估方法,其特点是定性的、主观的、无需专用的体系结构描述语言.本文提出以统一建模语言UML作为软件体系结构描述语言以及度量的软件体系结构的定量评估.针对UML的可视化、多视图、半形式化以及一致地应用在整个软件开发活动的特性,提出一组UML度量,从UML图所表达的信息含量、可视化影响以及图形建模元素之间的关联性这三个方面度量软件体系结构.分析并讨论这组UML度量在评估软件体系结构的规模、复杂性和结构性等质量属性方面的应用.     

Simplified proof of the blocking theorem for free-choice Petri nets

Every cluster in a bounded and live free-choice system has a unique blocking marking. It can be reached by firing an occurrence sequence, which avoids any transition of the cluster. This theorem is due to Gaujal, Haar and Mairesse. We will give a short proof using standard results on CP-subnets of well-formed free-choice nets.     

Feedback Control Logic for Backward Conflict Free Choice Nets

This paper discusses the forbidden state problem, as specified by generalized mutual exclusion constraints, in the context of supervisory control of discrete event systems modelled by Petri nets. The case of backward-conflict-free and free-choice uncontrollable subnets is considered and it is shown how to transform such subnets in well-formed free-choice nets. Then, the well-formed free-choice nets are decomposed in marked graph components by recurring to minimal T-invariants. The forbidden state problem is so reformulated for the obtained marked graph components into an equivalent one which is shown to be a linear programming problem. Thus, improving existing results in literature, a polynomial complexity solution, suitable for on-line control, is achieved. Free-choice relationship and cycle modelling, that frequently occur in real-life situations, are so allowed in the uncontrollable subnet     

From the specification to the implementation of norms: an automatic approach to generate rules from norms to govern the behavior of agents

Open multi-agent systems composed of heterogeneous, autonomous and independently designed agents are usually governed by a set of norms. The established norms regulate the behavior of the agents by pointing out their permissions, prohibitions and obligations. This paper presents a normative language to specify norms and proposes the implementation of such norms by using a rule-based system. The implementation is achieved by automatically transforming the specification of each norm of the system into a set of rules used to govern the behavior of the agents according to the norm. The governance system is able to activate and deactivate norms, to point out the norms violations and fulfillments and to inform about punishments and rewards.     

一种多Agent系统的社会规范

指出有关Agent社会规范研究中存在的问题,通过借鉴Coleman的社会学理论,提出一种基于权 利分配的Agent社会规范的概念.通过放宽平均权利分配的假设,给出了多Agent系统中社会规 范的形式定义,将规范的设计归结为约束满足问题.讨论了社会规范的合理性,并给出规范建 立和废除的条件.最后,针对对称利益局势讨论了社会规范的合理性,并给出了一个价值均衡 算法以改进规范的合理性,从而有助于推进基于市场的多Agent系统的研究.     

Diagnosis systems in medicine with reusable knowledge components

Constructing knowledge systems is viewed as a modeling activity for developing structured knowledge and reasoning models. To ensure well-formed models, the use of some knowledge engineering methodology is crucial. Additionally, reusing models can significantly reduce the time and costs of building a new application. Reusing knowledge components across different applications and domains can help acquire expert knowledge and accurately describe the reasoning process. In fact, current knowledge engineering research has taken major initiatives in the development of knowledge systems by reusing generic components, such as ontologies or problem-solving methods. The article shows how we developed a diagnosis-aid system by reusing and adapting genetic knowledge components for diagnosing eye emergencies.     

MRPPS—An interactive refutation proof procedure system for question-answering

In this paper a system termed the Maryland refutation proof procedure system (MRPPS) is described. MRPPS is an interactive system which gives the user the ability to create and maintain a core-bound data base and to input queries either as well-formed formulas in the first-order predicate calculus or as clauses. MRPPS consists of three basic components: (1) a set of inference rules for making logical deductions, many of which are based on the resolution principle; (2) a search strategy for heuristically determining the sequence in which to select base clauses and to perform deductions on clauses already generated; and (3) a base clause selection strategy that uses heuristic and semantic information for determining which data axioms and general axioms are to be brought to bear on the problem. These three components are described and MRPPS is compared to related work.     

物联网中企业信息交互中间件技术相关问题探讨

该文依据物联网规范,从企业应用需求的角度入手,分别介绍了物联网中的EPCIS服务,ONS服务以及它们对于安全性的要求和解决方案。通过对规范的深入理解和对企业间物联网系统信息交互的需求分析,给出了最终中间件的实现方案,并且给出一个参考实现。     

分布式数据开采研究

本文首先简单介绍了分布式数据开采的主要研究内容,然后介绍了分布式 数据开采研究的现状及一些实验系统。随后分析了分布式数据开采系统的体系结构应该具有的特点。最后,提出了分布式数据开采中一些重点研究问题。     

基于ADO动态属性的多表联结的数据更新

在满足范式设计要求的数据库表格中,多表联结查询是一个较常见的问题。本文讨论了ADO动态属性的含义、功能及其在Delphi编程环境中的调用方法,并结合相关的ADO动态属性深入剖析了多表联结查询的数据更新机制。     

良构子串表在自然语言处理中的程序化应用以花园幽径句为例

自然语言处理是计算语言学研究的方向之一,通常借助计算机技术进行自然语言的分析和解读。NS 流程图具有选择算法剖析的结构性特点。良构子串表具有保存剖析过程多种结构的特性。花园幽径句是句法加工过程中能产生行进式错位且对前期模式破旧立新的特殊句式。基于NS 流程图算法的良构子串表可用于对自然语言中的特殊现象(如花园幽径句)进行程序剖析,最终使这种程序分析法在语言学中得到应用成为可能。     

Norm selections in solutions to the minimal design problem

The recent algorithm of the author for solving the minimal design problem permits great flexibility in selection of norms as criteria of closeness for vector functions. Here it is shown that certain of these norms correspond to physically meaningful criteria of closeness based on system time responses, and are appropriate for use with the fast algorithm of Kung and Kailath as well.     

Iterative design of robust controllers under unknown bounded perturbation norms

A suboptimal robust controller for a multidimensional linear stationary nominal system with output- and control-operator perturbations and a bounded external perturbation is designed. Perturbation norms (weights) are assumed to be unknown and estimated from measurement data. The quality index of the closed-loop control system is taken to be the worst -norm for the output of the system in the class of admissible perturbations. The quality index for systems in the class of linear stationary stabilizing controllers is a fractional linear function of induced norms of transfer matrices of the closed-loop system and perturbation norms. The classical design of suboptimal robust controllers under known perturbation norms is reduced to a standard ₁-optimization problem, and optimal estimation of unknown perturbation norms is reduced to a linear programming problem. Therefore, the iterative sequential method of controller design and perturbation norm estimation is used as a heuristic method for designing suboptimal robust controllers under unknown perturbation norms. Modeling results corroborate the effectiveness of this method.Translated from Avtomatika i Telemekhanika, No. 4, 2005, pp. 110–126.Original Russian Text Copyright © 2005 by Sokolov.This work was supported by the Russian Foundation for Basic Research, project no. 02-01-00474.This paper was recommended for publication by A.P. Kurdyukov, a member of the Editorial Board     

Agent communication and artificial institutions

In this paper we propose an application-independent model for the definition of artificial institutions that can be used to define open multi-agent systems. Such a model of institutional reality makes us able also to define an objective and external semantics of a commitment-based Agent Communication Language (ACL). In particular we propose to regard an ACL as a set of conventions to act on a fragment of institutional reality, defined in the context of an artificial institution. Another contribution of the work presented in this paper is an operational definition of norms, a crucial component of artificial institutions. In fact in open systems interacting agents might not conform to the specifications. We regard norms as event-driven rules that when are fired by events happening in the system create or cancel a set of commitments. An interesting aspect of our proposal is that both the definition of the ACL and the definition of norms are based on the same notion of commitment. Therefore an agent capable of reasoning on commitments can reason on the semantics of communicative acts and on the system of norms.