TY  - CHAP
A1  - Biltchouk, Irina
A1  - Pahl, Peter Jan
T1  - Interaction of Data Bases and Graphical Interfaces in Civil Engineering
N2  - Applications for civil engineering tasks usually contain graphical user interfaces for the engineering processes. Persistent objects of the applications are stored to data bases. The influence of the interaction between a graphical user interface and a data base for the development of an civil engineering application is investigated in this paper. A graphic application for the linear elastic analysis of plane frames, which was previously developed with standard tools of the Java platform, is compared to a redesigned implementation using a generalized data base for persistent objects. The investigation leads to the following results : - A strict distinction between persistent and transient objects influences the class structure of an application, in particular the class structure of a graphical user interface. - The structure of an application depends on the logic for updating of references to persistent and transient graphical objects after an application is read from a file. - The complexity of the reference management can usually be handled better by just in time referencing associated with String - identifiers rather than by automated referencing associated with Name - identifiers.
KW  - Baubetrieb
KW  - Computerunterstütztes Verfahren
KW  - Graphische Benutzeroberfläche
KW  - Datenbank
Y1  - 2004
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20111215-1636
ER  - 
TY  - CHAP
A1  - Perevalova, Julia
A1  - Pahl, Peter Jan
T1  - Structural and Functional Dependence of Objects in Data Bases
N2  - Let the information of a civil engineering application be decomposed into objects of a given set of classes. Then the set of objects forms the data base of the application. The objects contain attributes and methods. Properties of the objects are stored in the attributes. Algorithms which the objects perform are implemented in the methods of the objects. If objects are modified by a user, the consistency of data in the base is destroyed. The data base must be modified in an update to restore its consistency. The sequence of the update operations is not arbitrary, but is governed by dependence between the objects. The situation can be described mathematically with graph theory. The available algorithms for the determination of the update sequence are not suitable when the data base is large. A new update algorithm for large data bases has been developed and is presented in this paper.
KW  - Baubetrieb
KW  - Computerunterstütztes Verfahren
KW  - Objektorientierung
KW  - Datenbank
Y1  - 2004
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20111215-1683
ER  - 
TY  - JOUR
A1  - Mironov, Vadim
A1  - Pahl, Peter Jan
T1  - A Prismatic Finite Element for Accurate Arch Dam Analysis
N2  - The displacements and stresses in arch dams and their abutments are frequently determined with 20-node brick elements. The elements are distorted near the contact plane between the wall and the abutment. A cantilever beam testbed has been developed to investigate the consequences of this distortion. It is shown that the deterioration of the accuracy in the computed stresses is significant. A compatible 18-node wedge element with linear stress variation is developed as an alternative to the brick element. The shape of this element type is readily adapted to the shape of the contact plane. It is shown that the accuracy of the computed stresses in the vicinity of the contact plane is improved significantly by the use of wedge elements.
KW  - Finite-Elemente-Methode
KW  - Physikalisches Verfahren
KW  - Dammbau
Y1  - 2004
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:gbv:wim2-20111215-2467
ER  -