Support for modeling relationships in object-oriented databases

Modeling real-world applications typically consists of two parts: the representations of entities of interest, and the representations of relationships among the entities. Object-oriented data models support the first task. This paper argues through examples that the second modeling task is not well supported in current object-oriented database systems. An extended object-oriented data model that facilitates both modeling tasks is developed. This extension provides support for both the representation of complex relationships among entities and their manipulations (queries, updates). A prototype implemented on the ONTOS database management system is briefly described.     

Maintenance of integrity during concurrent access in a building design database

This paper proposes an implementation structure and the corresponding relational model for a building design database. The structure strongly supports designer—database interaction by providing extremely versatile access mechanisms and an associated concurrrency control mechanism. It is demonstrated that the relational model provides a flexibility of access not readily available in other models. The implementation structure supports designer access to database entities by location, attribute value, and combinations of both. It also supports ad hoc groupings of data. At the same time it maintains the integrity of the database against violations caused by concurrent use. Existing concurrency control methods are explored and a new level of locking for concurrency control is proposed. The module is recommended as the optimal level to which a locking mechanism be applied.     

Development of an information model for composites design data

Material properties data, particularly those of advanced composite materials such as fiber-reinforced plastics, provides a very complex domain which is difficult to computerize. As a foundational activity supporting the development of material property databases, we have examined and modeled the data contained within this large, diverse, and intricate domain. Our primary objective was to gain a better understanding of the data involved in this system and their transformation and use. We examined the life cycle of a fiber-reinforced composite material, from a raw material to a manufactured product, focusing on the various applications which require and/or supply materials data and the types of materials data which must be included. A high-level information model was created to illustrate the overall picture of composite materials data which emerged from this analysis. This model provides a global view of the data encompassed in the domain of composite materials, and forms the basis of a formal conceptual model from which databases may be developed.     

Conceptual design of object-oriented database schemas using the binary-relationship model

We describe an algorithmic method for transforming a binary-relationship (BR) conceptual schema to an object-oriented (OO) database schema. The BR schema is a semantically rich diagram that represents the reality being modeled in terms of objects, relationships and constraints. It is easy to understand and serves as a communication tool between users and designers. Therefore it can be created in the early stages of system development, and later on be transformed into a specific OO database schema. The transformation method employs a multi-stage algorithm, which first identifies the essential objects in the BR schema, together with their relationships and constraints. These are then mapped to object classes, attributes, and constraints, maintaining the semantics and all types of constraints present in the conceptual schema.     

Computer aided design of database internal schema

A large number of complexly interrelated parameters are involved at the internal schema level design of database systems. Consequently, a single design model is seen to be infeasible. A package of three aids is proposed to assist a designer in step by step design of internal schema. The three aids pertain to splitting of a relation, merging of relations, and access strategy selection for a relation.     

The analysis of relationships in databases for rule derivation

Owing to the rapid growth in the sizes of databases, potentially useful information may be embeded in a large amount of data. Knowledge discovery is the search for semantic relationships which exist in large databases. One of the main problems for knowledge discovery is that the number of possible relationships can be very large, thus searching for interesting relationships and reducing the search complexity are important. The relationships can be represented as rules which can be used in efficient query processing. We present a technique to analyze relationships among attribute values and to derive compact rule set. We also propose a mechanism and some heuristics to reduce the search complexity for the rule derivation process. An evaluation model is presented to evaluate the quality of the derived rules. Moreover, in real world, databases may contain uncertain data. We also propose a technique to analyze the relationships among uncertain data and derive probabilistic rules.     

Supporting Semantic Diversity in the Relational Data Model: The Case of Multi-Face Attributes

In recent years various proposals have been offered for increasing the richness of the relational data model by addressing specific user requirements, particularly with regard to structural and behavioral expressiveness. Although there have been some criticisms of the semantic limitations of the model, few proposals have emerged to address them. In this paper we propose an extension of the model to address some of the semantic limitations around the use of multi-face attributes in everyday activity. We present a formal discussion of multi-face attributes and suggest how they can be accommodated in the relational model and relational database software systems. The resulting model offers a higher-level expressiveness and will provide the user with increased flexibility in the input, output and storage of data, and the specification of queries. Finally we outline some of the implications for database design methods that emerge for the extension.     

Design of engineering databases: A case for more varied semantic modelling concepts

Interest in database support for engineering applications is rapidly growing. In this paper we concentrate on conceptual database design and address the question of what a semantic model should look like, that meets the needs of engineering applications and is sufficiently formal to support validation, optimization, analysis, as well as transformation to an implementation schema. We present several case studies of engineering databases in order to determine major modelling requirements, and compare these to modelling concepts from the data base and knowledge representation fields. We demonstrate that the main issue is not adding further concepts, but to integrate the existing ones in a selective and precise fashion. We suggest to do so by tailoring the semantic model, starting from a set of base concepts and extending these. An initial model and an extensibility mechanism allowing an explicit and declarative definition of higher-order abstractions are presented. This is demonstrated by specifying some simple concepts such as generalization and a more complex time concept for image sequence evaluation.     

A conceptual model for the logical design of temporal databases

Although widely advocated as a tool for the conceptual modelling of data, the Entity-Relationship (E-R) model [4] and its extensions are generally lacking in constructs to model the dynamic nature of the real world, making them inadequate for designing temporal databases. This research first extends the E-R model to a Temporal Event-Entity-Relationship Model (TEERM), by introducing events as an additional construct. Second, a method is proposed for mapping this conceptual model into a temporal relational model for the logical design of temporal relational databases with a corresponding set of integrity constraints. The model is illustrated with an example and evaluated using a set of criteria proposed by ^{Batini et al. [2]}. The model appears to be expressive, simple and easy to use, and should, therefore, aid the temporal database design process significantly.     

Tool support for the design and management of context models

A central task in the development of context-aware applications is the modeling and management of complex context information. In this paper, we present the NexusEditor, which can ease this task by providing a graphical user interface to design schemas for spatial and technical context models, interactively create queries, send them to a server and visualize the results. One main contribution is to show how schema awareness can improve such a tool: The NexusEditor dynamically parses the underlying data model and provides additional syntactic checks, semantic checks, and short-cuts based on the schema information. Furthermore, the tool helps to design new schema definitions based on the existing ones, which is crucial for an iterative and user-centric development of context-aware applications. Finally, it provides interfaces to existing information spaces and visualization tools for spatial data like GoogleEarth.     

Data and knowledge modeling for design–process planning integration of sheet metal components

Realizing design–process planning integration is vital to the competitiveness of manufacturing organization and its ability to respond rapidly to market changes. Many attempts have been made in the past proposing the integration of the two activities based on product data models. However, both design and process planning activities are knowledge intensive. An effective integration is possible only if both data and knowledge models form a basis for integration. This paper presents key issues related to data and knowledge modeling for integration of design (CAD) and process planning (CAPP) activities for sheet metal components. Previous attempts to model data and knowledge have concentrated only on either design or process planning and not from an integration point of view. Moreover, in these attempts data and knowledge models have been proposed without attempting to relate the two. The same has been overcome in the present work. An integration framework based on data and knowledge is proposed at the end and discussed for domain of design–process planning integration of sheet metal components.     

基于Honeypot网络安全技术的数据捕获模块设计

在对传统的防火墙和入侵检测技术探讨的基础上,通过对入侵诱骗技术Honeypot系统的研究,设计了一个基于Honeypot技术的数据捕获模块.介绍了基于Linux系统的数据捕获实现方法,其中使用了三层数据捕获来监控攻击者的入侵行为,这样尽可能多地捕获并学习攻击者的相关信息,从而保护系统安全.     

Protection of intellectual property based on a skeleton model in product design collaboration

As markets are globalized and competition among companies increases, corporations strive to remain competitive by focusing their abilities on key parts of a new product, while outsourcing remaining parts to other companies. In these circumstances, relationships with business partners with regard to product design are not rigid and vertical, but rather, flexible and horizontal; thus, partners today can be competitors in the future. Therefore, the intellectual property of a participating company should be protected from other collaborating companies during the product design process. However, this safeguard should not be an obstacle to product design collaboration itself. As a solution to this problem, we propose a method to share a skeleton model among collaborating companies. By using this model, participating companies can share essential data required for the detail design of those components of a product for which they are responsible, while ensuring security of their intellectual property. The feasibility of the proposed method has been demonstrated through experiments in a development scenario involving a tub component of a washing machine.     

Development of an object-oriented blackboard model for stamping process planning in progressive die design

This paper reports preliminary work to investigate the suitability of using a blackboard framework as a problem-solving model for stamping process planning in progressive die design. The model is described at two levels: knowledge level and computational level. The knowledge level describes how the stamping process planning domain is represented in a blackboard architecture. The computational level describes how the blackboard architecture is modeled and implemented using object technology. A software prototype has been developed using CLIPS and C++ interfaced with Solid Edge CAD system. An example is presented to illustrate the feasibility and practicality of the proposed approach.     

数据仓库建模和设计的最新进展

从概念建模、逻辑建模、设计方法、互操作性和元数据4个方面综述了现阶段数据仓库的研究内容,分析了数据仓库的研究现状,指出了数据仓库新的应用前景和面临的挑战,以指导数据仓库的进一步研究。     

大宗油料供应数据仓库模型设计与实现

针对传统分散的油料供应管理系统中数据分析与决策支持能力的不足,提出了基于联机分析处理的大宗油料供应数据仓库模型设计方案,并用SQL语言阐述了模型的实现方法。     

工业自动化控制中数据查重系统的设计与实现

本文系统地讨论了烟草工业自动化系统中用户管理数据库系统内经常出现的数据重复问题，并建立了几种数据重复判断模型，最后评定了几种模型的优缺点。     

Minimal model generation for refined answering of generalized queries in disjunctive deductive databases

Generalized queries are defined as sets of clauses in implication form. They cover several tasks of practical importance for database maintenance such as answering positive queries, computing database completions and integrity constraints checking. We address the issue of answering generalized queries under the minimal model semantics for the class of disjunctive deductive databases (DDDBs). The advanced approach is based on having the query induce an order on the models returned by a sound and complete minimal model generating procedure. We consider answers that are true in all and those that are true in some minimal models of the theory. We address the issue of answering positive queries through the construction of the minimal model state of the DDDB, using a minimal model generating procedure. The refinements allowed by the procedure include isolating a minimal component of a disjunctive answer, the specification of possible updates to the theory to enable the derivability of certain queries and deciding the monotonicity properties of answers to different classes of queries.     

Data space mapping for efficient I/O in large multi-dimensional databases

In this paper, we propose data space mapping techniques for storage and retrieval in multi-dimensional databases on multi-disk architectures. We identify the important factors for an efficient multi-disk searching of multi-dimensional data and develop secondary storage organization and retrieval techniques that directly address these factors. We especially focus on high dimensional data, where none of the current approaches are effective. In contrast to the current declustering techniques, storage techniques in this paper consider both inter- and intra-disk organization of the data. The data space is first partitioned into buckets, then the buckets are declustered to multiple disks while they are clustered in each disk. The queries are executed through bucket identification techniques that locate the pages. One of the partitioning techniques we discuss is especially practical for high dimensional data, and our disk and page allocation techniques are optimal with respect to number of I/O accesses and seek times. We provide experimental results that support our claims on two real high dimensional datasets.