Extending the ODMG object model with triggers

We extend the standard for object-oriented databases, ODMG, with reactive features, by proposing a language for specifying triggers and defining its semantics. This extension has several implications, thus we make three different specific contributions. First, the definition of a declarative data manipulation language for ODMG, which is missing in the current version of the standard; such a definition requires revisiting data manipulation in ODMG and also addressing issues related to set-oriented versus instance-oriented computation. Then, the definition of a trigger language for ODMG, unifying also the SQL:1999 proposal and providing support for trigger inheritance and overriding. Finally, the development of a formal semantics for the proposed data manipulation and trigger languages.     

Extending standard evolutionary programming with self-adaptive stable distributions

Applications in evolutionary programming have suggested the use of further stable probability distributions, such as Cauchy and Lévy, in the random process associated with the mutations, as an alternative to the traditional, also stable, normal distribution. This work goes further along the encouraging results of the latter, by extending them in a self-adaptive way, with algorithms that are in tune with the standard lineage of evolutionary programming. Evaluations that rely upon standard analytical benchmarking functions and comparative performance tests between them were carried out in respect to the baseline defined by the standard evolutionary programming algorithm that relies on normal distribution. Additional comparative studies were made in respect to various self-adaptive approaches, also proposed herein, and a method drawn from the literature. The results lead to numerical and statistical superiority of the more general stable distribution based approach, when compared with the baseline, and is unclear in regard to the method drawn from the literature, possibly due to distinct implementation details.     

ODMG对象操纵语言的改进和实现

讨论了TR－OODB客户端对象操纵语言的设计和实现，基于面向对象数据库标准ODMG3．0，给出了一种利用操作系统高级特性，最大限度地提高持久对象引用效率，并保持与现有ODMG标准兼容的OML实现方案，文中最后介绍了实现的若干关键技术。     

基于ODMG Java绑定的面向对象数据库 存储管理①

针对面向对象数据库(OODB)的存储管理进行研究,依照ODMG3.0标准,并以Java绑定方式提供实现方案。通过对典型对象存储结构的研究,给出一种兼顾各种类型数据特点的分层对象存储结构。结合这里使用的体系结构,给出一种基于分槽页结构的改进文件存储结构,将存储单位由页面替换成数据库文件。分析OODB中引入的索引,给出一种基于B+-Tree,结合继承层次和聚集层次的综合索引策略。     

基于ODMG Java绑定的面向对象数据库 存储管理①

针对面向对象数据库（OODB）的存储管理进行研究,依照ODMG3．0标准,并以Java绑定方式提供实现方案。通过对典型对象存储结构的研究,给出一种兼顾各种类型数据特点的分层对象存储结构。结合这里使用的体系结构,给出一种基于分槽页结构的改进文件存储结构,将存储单位由页面替换成数据库文件。分析OODB中引入的索引,给出一种基于B＋－Tree,结合继承层次和聚集层次的综合索引策略。     

用继承扩展XML-RL

XML正在成为Internet上数据描述和交换的标准，用一些重要的面向对象的特征扩展基于高级数据模型上的以规则为基础的XML查询语言XML-RL．首先用元素层次，多重继承和多态扩展了XML-RL数据模型．然后扩展XML-RL以支持多态元素，多态引用，独占元素和独占引用．     

用Java扩展XSLT

XSLT提供了一种将XML文档转换为HTML的强有力的工具.然而,当这种转换需要涉及更多逻辑的时候,就会显现出它的不足之处.文中讲述了如何使用Java扩展XSLT,从而更好地发挥两种语言的特色.最后给出一实例来具体展示如何将XML节点传送到Java类并返回到样式表以进一步处理.     

用Java扩展XSLT

XSLT提供了一种将XML文档转换为HTML的强有力的工具。然而,当这种转换需要涉及更多逻辑的时候,就会显现出它的不足之处。文中讲述了如何使用Java扩展XSLT,从而更好地发挥两种语言的特色。最后给出一实例来具体展示如何将XML节点传送到Java类并返回到样式表以进一步处理。     

Measuring and modelling the performance of a parallel ODMG compliant object database server

Object database management systems (ODBMSs) are now established as the database management technology of choice for a range of challenging data intensive applications. Furthermore, the applications associated with object databases typically have stringent performance requirements, and some are associated with very large data sets. An important feature for the performance of object databases is the speed at which relationships can be explored. In queries, this depends on the effectiveness of different join algorithms into which queries that follow relationships can be compiled. This paper presents a performance evaluation of the Polar parallel object database system, focusing in particular on the performance of parallel join algorithms. Polar is a parallel, shared‐nothing implementation of the Object Database Management Group (ODMG) standard for object databases. The paper presents an empirical evaluation of queries expressed in the ODMG Query Language (OQL), as well as a cost model for the parallel algebra that is used to evaluate OQL queries. The cost model is validated against the empirical results for a collection of queries using four different join algorithms, one that is value based and three that are pointer based. Copyright © 2005 John Wiley & Sons, Ltd.     

Extending the fuzzy database with fuzzy numbers

The fuzzy relational database model originated by the authors permits fuzzy domain values from a discrete, finite universe. The model is extended here by demonstrating that fuzzy numbers may be employed as domain values without loss of consistency with respect to representation or the relational algebra. Where equivalence is required in an ordinary relational database, similarity is employed in a fuzzy relational database. For discrete, finite universes, similarity between atomic elements is described via a fuzzy similarity relation with max-min transitivity. Two or more fuzzy numbers are defined to be α-similar if their union forms a continuous α-level set over the real line. This convention effects the partitioning of fuzzy number domains that is necessary to assure the well-definedness of the fuzzy relational algebra.     

Extending Sledgehammer with SMT Solvers

Sledgehammer is a component of Isabelle/HOL that employs resolution-based first-order automatic theorem provers (ATPs) to discharge goals arising in interactive proofs. It heuristically selects relevant facts and, if an ATP is successful, produces a snippet that replays the proof in Isabelle. We extended Sledgehammer to invoke satisfiability modulo theories (SMT) solvers as well, exploiting its relevance filter and parallel architecture. The ATPs and SMT solvers nicely complement each other, and Isabelle users are now pleasantly surprised by SMT proofs for problems beyond the ATPs’ reach.     

Extending statecharts with temporal logic

The task of designing large real-time reactive systems, which interact continuously with their environment and exhibit concurrency properties, is a challenging one. The authors explore the utility of a combination of behavior and function specification languages in specifying such systems and verifying their properties. An existing specification language, statecharts, is used to specify the behavior of real-time reactive systems, while a new logic-based language called FNLOG (based on first-order predicate calculus and temporal logic) is designed to express the system functions over real time. Two types of system properties, intrinsic and structural, are proposed. It is shown that both types of system properties are expressible in FNLOG and may be verified by logical deduction, and also hold for the corresponding behavior specification     

Extending UML with coordination contracts

Coordination contracts are a software analysis and design construct which enable separation between the stable components of a system and the rules which define the interactions of these components. This separation supports rapid evolution of rules without requiring modification to components. In this paper we show that contracts can be defined in UML, and we define an MDA-based development process which makes use of contracts.Communicated by Jos Warmer     

Extending Datalog with Declarative Updates

The semantics of static deductive databases is well understood based on the work in logic programming. In the past decade, various methods to incorporate update constructs into logic programming and deductive databases have been proposed. However, there is still no consensus about the appropriate treatment of dynamic behavior in deductive databases. In this paper, we propose a language called DatalogU, which is a minimal but powerful extension of Datalog with updates to base relations. DatalogU allows the user to program set-oriented complex database transactions with concurrent, disjunctive and sequential update operations in a simple and direct way. It has a simple and intuitive declarative semantics that naturally accounts for set-oriented updates in deductive databases.     

Extending DBMSs with satellite databases

In this paper, we propose an extensible architecture for database engines where satellite databases are used to scale out and implement additional functionality for a centralized database engine. The architecture uses a middleware layer that offers consistent views and a single system image over a cluster of machines with database engines. One of these engines acts as a master copy while the others are read-only snapshots which we call satellites. The satellites are lightweight DBMSs used for scalability and to provide functionality difficult or expensive to implement in the main engine. Our approach also supports the dynamic creation of satellites to be able to autonomously adapt to varying loads. The paper presents the architecture, discusses the research problems it raises, and validates its feasibility with extensive experimental results.     

Extending FABRIK with model constraints

Forward and Backward Reaching Inverse Kinematics (FABRIK) is a recent iterative inverse kinematics solver that became very popular because of its simplicity, convergence speed and control performance, especially in models with multiple end effectors. In this paper, we extend and/or adjust FABRIK to be used in problems with leaf joints and closed‐loop chains and to control a fixed inter‐joint distance in a kinetic chain with unsteady data. In addition, we provide optimisation solutions when the target is unreachable and a proof of convergence when a solution is available. We also present various techniques for constraining anthropometric and robotic joint models using FABRIK and provide clarifications and solutions to many questions raised since the first publication of FABRIK. Finally, a human‐like model that has been structured hierarchically and sequentially using FABRIK is presented, utilising most of the suggested joint models; it can efficiently trace targets in real time, without oscillations or discontinuities, verifying the effectiveness of FABRIK. Copyright © 2015 John Wiley & Sons, Ltd.     

用继承扩展XML Schema

XML正成为Internet上数据描述和交换的主要标准,因此对面向对象XML存储研究变的很重要。扩展后的XMLSchema支持面向对象XML,通过对XMLSchema文档的解析得到面向对象XML文档中元素之间的关系,这些关系不仅支持新的数据模型,而且支持新的查询方式。在扩展XMLSchema的语法后,介绍扩展后XMLSchema中继承信息查找的算法设计。     

Extending the data parallel paradigm with data-dependent operators

This paper presents a new scheme for software support of image analysis. It extends the data parallel programming model with the notion of a special data-dependent operand. Thanks to its ability of storing the location of pixel aggregates (connected components), manipulations on multiple image areas can be expressed in terms of whole image transformations. This general model, called the associative net extension, gives programmers flexible ways of handling regions and contours, as shown by a set of examples and it has been implemented on single processor machines to verify its performance and to test its effectiveness in real cases. Implementations on special purpose hardware or multi-processor machines are being tested and look promising, too.