Query processing of geometric objects with free form boundarie sin spatial databases

The increasing demand for the use of database systems as an integrating factor in CAD/CAM applications has necessitated the development of database systems with appropriate modelling and retrieval capabilities. One essential problem is the treatment of geometric data which has led to the development of spatial databases. Unfortunately, most proposals only deal with simple geometric objects like multidimensional points and rectangles. On the other hand, there has been a rapid development in the field of representing geometric objects with free form curves or surfaces, initiated by engineering applications such as mechanical engineering, aviation or astronautics. Therefore, we propose a concept for the realization of spatial retrieval operations on geometric objects with free form boundaries, such as B-spline or Bezier curves, which can easily be integrated in a database management system. The key concept is the encapsulation of geometric operations in a so-called query processor. First, this enables the definition of an interface allowing the integration into the data model and the definition of the query language of a database system for complex objects. Second, the approach allows the use of an arbitrary representation of the geometric objects. After a short description of the query processor, we propose some representations for free form objects determined by B-spline or Bezier curves. The goal of efficient query processing in a database environment is achieved using a combination of decomposition techniques and spatial access methods. Finally, we present some experimental results indicating that the performance of decomposition techniques is clearly superior to traditional query processing strategies for geometric objects with free form boundaries

A storage and access architecture for efficient query processing in spatial database systems

Due to the high complexity of objects and queries and also due to extremely large data volumes, geographic database systems impose stringent requirements on their storage and access architecture with respect to efficient query processing. Performance improving concepts such as spatial storage and access structures, approximations, object decompositions and multi-phase query processing have been suggested and analyzed as single building blocks. In this paper, we describe a storage and access architecture which is composed from the above building blocks in a modular fashion. Additionally, we incorporate into our architecture a new ingredient, the scene organization, for efficiently supporting set-oriented access of large-area region queries. An experimental performance comparison demonstrates that the concept of scene organization leads to considerable performance improvements for large-area region queries by a factor of up to 150

The Issues And Solutions Of Integrating DBMS To A Multi-DBMS

Many organizations invest heavily in heterogeneous databases according to organizational functions. These heterogeneous databases are stand-alone systems that do not interact with one another. The objective of this paper is to introduce a multi-database system (MDBMS) that interacts with other heterogeneous DBMS within the organization to integrate information processing. In this paper, we discuss the potential inconsistencies in integrating heterogeneous databases. We further extend to include issues in designing a MDBMS. With a MDBMS, data sharing across organization reduces overheads and costs, thus, provides a competitive advantage to the global firms

Sistema CADD para projeto de estruturas de concreto armado

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro TecnologicoO presente trabalho descreve um sistema CADD (Computer Aided Design An Drafting) para projeto de estruturas de concreto armado. A ênfase do trabalho está no estudo da arquitetura necessária à elaboração de um sistema capaz de progredir de acordo com os avanços tecnológicos e facilitar a integração com sistemas já existentes, com isto reduzindo custos de atualizações e adaptações necessárias a novos padrões. São discutidos os aspectos relacionados aos diferentes níveis de representação necessários a um sistema deste tipo, bem como as dificuldades existentes em relação à unificação de sistemas de características diversas de forma integrada. O objetivo do sistema é possibilitar aos engenheiros estruturais, através de uma interface gráfica, uma utilização rápida, eficiente e segura das ferramentas de projeto correntes, da mesma forma que adicionar novas alternativas, tais como otimização de componentes estruturais e representação funcional orientada a objetos

Data base projecting in the field of education computer software

U radu su definisane teorijske postavke povezivanja koncepata otvorenog i zatvorenog sveta u jedinstven sistem za rukovanje bazom podataka u režimu otvorenog, zatvorenog i otvorenog/zatvorenog sveta. Opisan je konkretan programski sistem BASELOG, koji je razvijen na datim teoretskim postavkama. Opisan je postupak projektovanja baza podataka u oblasti obrazovnog softvera, koji je zasnovan na BASELOG-sistemu.In this work theoretical bases of connecting concept open and closed world in one data base management system which works through open, closed and open/closed world are defined. BASELOG-program system is descripted and developed on given theoretical bases. There is also descripted process of data base projecting in the field of education software which is based on BASELOG-system

SLEMS : a knowledge based approach to soil loss estimation and modelling

ThesisThesis (M.Sc.E.), University of New Brunswick, 199

Heuristics and multi-dimensional physical database design

An expert system approach has recently been used in parameter selection for VSAM (Virtual Storage Access Method) file organisation [AL87a]. This system has been developed to aid in-house users to apply relevant facts and heuristics to optimise VSAM file design. Multi-dimensional physical database design is more sophisticated and complicated than VSAM file design. The expert system approach can be applied to select and tune physical database design for various applications. A great deal of work has been done in developing diverse algorithms or access methods to organise automated information on secondary storage devices [FA86b] [FR86] [FR88] [GU84] [HU88a] [KS88a] [KS86] [L087] [NI84] [OR88b] [OR86] [OT85] [R081], etc. However, little work has been done to enable designers to select an access method which matches a projected application profile (features and requirements) and perceived strengths and weaknesses of candidate algorithms. This thesis considers a number of grid based algorithms and makes expert assessments of each according to its strengths and weaknesses. It analyses features of various access methods and using expert knowledge matches features for a range of m-d (multi­ dimensional) algorithms with corresponding characteristics of an application. The knowledge-based system presented in this thesis can be applied either manually or computerised to give a systematic approach to m-d algorithm selection. A system is proposed to (1) heuristically select an initial algorithm; (2) describe how the selection process is evaluated against actual m-d algorithm performance and (3) show how the results of the evaluation can be used to refine expert knowledge embodied in the selection system. Heuristic assessments are given for several m-d access algorithms. Examples are presented to show how these heuristics are used to select a m-d access algorithm for a specific application. It is reasonable to suppose that the initial heuristic assessments are not entirely accurate. A tuning mechanism for the system heuristics is given in section 4.9. The system selection process is thereby, able to adjust to real world results. Finally, we present a simple example to illustrate how the proposed system works