一种基于矩阵的MBR方向关系模型

在空间主方向关系推理的研究中,方向关系模型是其中一项至关重要的课题。介绍了区间代数模型、矩形代数模型和极小边界盒模型,提出了区间代数的矩阵表示方法,并给出了以矩阵表示的区间代数和方向关系矩阵之间的转换方法。     

基于语义关系约束和词语关系信息的句向量研究

针对现有的句向量学习方法不能很好的学习关系知识信息、表示复杂的语义关系,提出了基于PV-DM模型和关系信息模型的关系信息句向量模型（RISV）,该模型是将PV-DM模型作为句向量训练基本模型,然后为其添加关系信息知识约束条件,使改进后模型能够学习到文本中词语之间的关系,并将关系约束模型（RCM）模型作为预训练模型,使其进一步整合语义关系约束信息,最后在文档分类和短文本语义相似度两个任务中验证了RISV模型的有效性。实验结果表明,采用RISV模型学习的句向量能够更好地表示文本。     

区间约束及其代数查询语言

提出了区间约束和基于区间约束的代数查询语言。区间约束与密序约束相经,增加了简单的加减运算,具有更强的描述能力,同时区间约束元组有简洁,唯一的规范区间表示,文中给出了计算区间约束的规范区间表示的算法,针对区间约束关系,定义了基本代数操作的语法及语义,研究了代数查询语言,并证明代数约束查询语言满足封闭性,最后讨论了区间约束的实现与应用。     

访问控制框架中的策略加权

本文针对访问控制框架中的策略给出加权因子以体现其在策略框架中的重要性及对访问决定的影响程度。在模糊逻辑中加权模型真值计算思想上,提出访问控制框架加权策略下访问请求判定模型。该模型结合计算机逻辑中表示析取和合取的不同操作符,给出加权策略下访问判定的计算公式,访问判定值再与系统访问判定门陷值进行比较,以决定该访问请求是否授权。模型通过计算访问请求的授权许可值而给出判定,这比传统的访问请求授权方法更细粒度、易于理解,更能满足实际系统的需要,并增强系统的安全性。     

数据管理的演进（四）

统一表示的关系模型 实体和关系在关系模型中是统一表示的。关系模型对数据定义、数据浏览和数据操作有统一的语言,而不是针对不同的任务有不同的语言。更重要的是,关系代数将记录集合(关系)视为一个组,运算子对整个记录集合操作,其结果也为记录集合。关系数据模型和运算子允许更短和更简单的程序。例如,如图所示,我们的航线数据库可表示为五个表。关系系统不是隐含地存储航班和旅程的关系,而是显示地存储每个航班-旅程对,并视之为一个记录(见图中的“Segment”表)。     

支持虚拟企业的过程建模和工作流管理系统

针对虚拟企业提出了一种基于产品开发制造全过程分解和活动描述的形式化过程建模方法,在组成过程的任务中存在许多约束关系,如使能约束和促进约束,每个任务可以分解成许多活动,可以用企业本体论来表示这些活动、任务、状态和约束等,企业本体论是以情景演算来表示语义的,同时,建立了与过程模型相分离的组织模型活动、任务、状态和约束等,企业本体论是以情景演算来表示语义的。同时,建立了与过程模型相分离的组织模型;在此基础上,建立了一个工作流管理系统来支持虚拟的运行。文中提出一种由活动模型、意向模型、技能模型和伙伴模型等构成的Agent模型,来实现工作流管理,并通过构建可嵌套的Agent联帮增强系统的柔性。     

基于嵌套语义的约束代数

1 引言约束数据库近期被Kanellakis等提出作为处理空间数据的一般性框架。约束数据库用约束来建模和检索数据。在数据层,约束能用有限的形式来表示可能是无限的关系元组集。例如,约束x~2 y~2≤9表示中心在点(0,0)处,半径为3的圆。在查询语言层,约束通过允许数学计算而增强了简单关系语言的表达能力,同时约束查询语言保留了关系查询语言的所有特征,如封闭性和自底向上求值。关系代数能被扩充来处理约束关系,这个新的代数叫做约束代数CALG。     

基于对象的分布式实时系统调度模型研究

为了解决分布式实时系统有关分配和调度等问题，给出并用形式化方法描述了一种基于对象分布式实时系统调度的通用模型。该模型包括表示时限的绝对时间约束，表示周期属性的周期约束，表示各种前趋关系和同步要求的相对时间约束以及保证资源使用一致性的一致性约束，此外该模型克服了以往模型不能在应用系统的逻辑和功能部件上描述系统实时的约束的不足，允许从方法和活动上描述所需的约束，降低了单一约束描述的繁杂程度，为了能够使用现有调度算法进行任务调度，讨论了约束转换的问题，给出了高层约束到底层约束的转换规则和相应的转换算法。     

基于改进鱼群算法的几何约束求解

几何约束求解是CAD建模中的关键技术。针对求解质量不高和求解速度慢的问题,进行了研究。提出了一种鱼群算法和混沌算法相结合的几何约束求解方法。首先,将CAD模型中的几何约束关系表示为一组代数方程组;然后,利用代数方程组来构造目标函数。将几何约束求解问题转换为目标函数的优化问题。最后,使用混沌算法来改进鱼群算法以寻找目标函数的最优解。实验结果表明：该方法可以有效地解决几何约束问题。     

基于语义对象网络模型的产品知识表达方法

为表达产品知识及其语义内涵和约束关系,提出采用语义对象网络模型（Semantic Object Semantic Networks,SOSNs）表达产品知识。SOSNs是基于图并结合面向对象方法表达的知识模型,其中节点表示产品语义对象,有向边显性定义语义对象之间的语义关系,这种基于图的语义模型能够清晰的表示产品功能、行为、原理、结构、配置管理、约束等知识及其语义关系,将与产品开发相关的知识集成为一个逻辑整体,形成分层的结构化语义对象网络结构,便于组织和管理产品知识,易于实现知识的共享和重用。     

类汉语组合查询驱动工具的设计与实现

本文讨论面向多媒体数据对象的、可按照类汉语方式进行条件组合的多功能查询模式驱动工具的ＦＩＭＳＦＩＮＤ的用户操作界面的综合设置、主要设计目标、查询模式驱动的基本思想、系统总体的逻辑结构、自学习式查询的优化技术以及编程实现技术等方面的相关问题,ＦＩＭＳＦＩＮＤ已分别由Ｔｕｒｂｏｃ Ｃ和ＶＣ＋＋编程实现,并被成功地应用于数十余个中文信息系统的研制开发之中。     

A graphical database interface

A graphical database interface suitable for casual, naive users is described. It provides the user with a logical model of the database; this model typically being an abstraction of the actual database structure, and with an easy means of specifying a query through the use of a pointing device. The interface is a front-end processor and is logically separate from the database management system, it is thus possible to use it with any system.     

数据库汉语查询句中查询目标信息的研究

在自然语言处理的研究中，最有希望的应用领域之一是自然语言接口。计算机对自然语言中的查询语言理解的正确程度是自然语言接口质量好坏的关键。通过对汉语查询句——即用于数据库自然语言查询的祈使句和特指问句、是非问句、正反问句、选择问句等共五类句型的研究，建立并研究了复合概念、逻辑概念与标准概念的内在联系，将查询目标概念分解为直接查询目标、逻辑推理目标和比较判断目标三个阶段，研究了这三个阶段的关系。     

数据修复与一致性查询处理研究

在数据库以及集成系统中通常存在违背数据约束的不一致查询问题。修复是解决该问题的主要手段之一,但目前还缺乏基于修复、约束与查询的统一模型研究。提出了基于删除元组修复、满足多种类型约束的一致性查询算法;阐明了具有简洁特性的约束定义与查询语句结构;构建了新的查询与修复系统模型,将关系实例集、非空的约束集、查询定义、修复方法等统一到模型中,以产生满足一致性约束要求的查询结果。所研究的方法、语言以及模型通用性强、适用面广,不局限于特定质量问题的修复与查询。     

Foundations for object-oriented query processing

A minimal framework for an object-oriented query language standard should (1) include a formal definition of a high-level data model and the syntax and semantics of associated query languages, (2) provide the functionality of relational query languages, and (3) support proofs of correctness of transformations for logical query optimization. In this paper, a high-level conceptual model for object-oriented query processing is discussed; the model includes widely-used structural abstractions such as the isa relationship, associations (properties) between complex objects and complex objects/values, and inheritance of properties. A formal, algebraic query language for the model, inspired by relational algebra, is presented. Operators of the algebra allow queries based on values, queries that manipulate entire objects, and queries that construct new objects from existing objects/values. All queries retain connections to existing database objects, providing logical access paths to data. Each query result is a class, so the algebra has the closure property. The intensional and extensional results of query operators are summarized. Two forms of logical query optimization supported by the query algebra are outlined: algebraic transformations and classifier-based optimizations (optimizations which employ inclusion and exclusion dependencies between classes).     

Web信息的结构化及其查询视图研究

Web并不是传统的关系数据库。在WWW浏览器上进行信息搜索时,常常难于快速有效地得到查询结果。就Web站点信息库的数据模型化、关系代数演算及关系视图的建立加以探讨,基于这一模式结构的Web站点信息查询便易于表达和实现。     

An object-oriented query evaluation scheme for logical databases inmassively parallel environment

Taking advantage of the structure of logical representations, we report an algorithm that evaluates conjunctive queries in a massively parallel environment under an object-based representation for deductive databases. By distributing objects in a database, we show that parallel evaluation of a query can be achieved in a cooperative way so that the conventional tuple-by-tuple, operation-by-operation evaluation strategy can be replaced by a global, parallel matching approach. With the proposed scheme, all conjuncts of a given query can be examined at the same time, which enables us to eliminate the need of any temporary relation. On the other hand, compared with the interpretive method, we show that any data dependency imposed by shared variables is no longer a major problem in achieving AND-parallelism by the proposed scheme     

Adding inclusion dependencies to an object-oriented data model with uniqueness constraints

We study an object-oriented data model that allows to express both uniqueness constraints and inclusion dependencies as semantic constraints. The data model is based on a subset of F-logic. Uniqueness constraints comprise path functional dependencies which generalise functional dependencies and reflect the navigational power of object-oriented query languages. As inclusion dependencies, we consider explicit class inclusion constraints, besides inclusions required by class hierarchies, and onto constraints that enforce reachability of objects. For these classes of semantic constraints we present an axiomatisation and prove its inference rules to be correct and complete with respect to general logical implication, leaving the decision problem open. The completeness proof combines the known construction for path functional dependencies alone with a possibly infinite model generation process to enforce onto constraints. The results prepare the grounds for normal forms in object-oriented data models and subsequently for computer aided object-oriented database design, following the decomposition approach for the relational data model. Beyond the application for schema design, the achievements could also be exploited for related tasks like semantic query optimisation and mediated data integration within a variety of graph based data models. Received: 11 October 2000 / 27 January 2003     

约束规划方法在原油混输调度中的应用

应用约束规划方法建立炼厂原油混输模型,并通过搜索求解获得可操作的调度方案。约束规划允许以逻辑约束表达混输过程中的操作规则,使模型简洁直观,而对整型变量及非线性约束不敏感,则降低了模型的求解难度。选取了一个时间跨度为300小时实际调度问题作为案例,模型中包含约8000个变量和14000条约束,在普通PC机上计算求解,能够在30秒内获得调度方案,方案具有可操作性且优于人工方案,表明以约束规划方法解决原油混输调度问题是可行的。     

Multimodal Data Modeling Technology and Its App-19lication for Cloud-edge-device Collaboration

In the cloud-edge-device collaboration architecture, data types are diverse, and there are differences in storage resources and computing resources at all levels, which brings new challenges to data management. The existing data models or simple superposition of data models are difficult to meet the requirements of multimodal data management and collaborative management in the cloud-edge-device. Therefore, research on multimodal data modeling technology for cloud-edge-device collaboration has become an important issue. The core is how to efficiently obtain the query results that meet the needs of the application from the cloud-edge-device architecture. Starting from the data types of the three-layer data of cloud-edge-device, in this paper we propose a multimodal data modeling technology for cloud-edge-device collaboration, give the definition of multimodal data model based on tuples, and design six base classes to achieve a unified representation of multimodal data. The basic data operation architecture of cloud-edge-device collaborative query is also proposed to meet the query requirements of cloud-edge-device business scenarios. The integrity constraints of the multimodal data model are given, which lays a theoretical foundation for query optimization. Finally, a demonstration application of the multimodal data model for cloud-edge-device collaboration is given, and the proposed data model storage method is verified from the three aspects of data storage time, storage space, and query time. The experimental results show that the proposed scheme can effectively represent the multimodal data in the cloud-edge-device collaboration architecture.