CONTENTS &
ABSTRACTS
In English. Summaries in Estonian
Proceedings of the
Estonian Academy of Sciences.
Engineering
Volume 8 No. 1
March 2002
Techniques
of combination of metamodel extensions; 3–17
Alar Raabe
Abstract. Extensions to the generic analysis and design metamodels (for example, UML meta-models) are needed to support an effective analysis and design process. Extended analysis meta-models that embody domain knowledge, and extended design metamodels which embody architecture-specific knowledge, can be used in software engineering as a guiding framework. Therefore it is necessary to combine several metamodel extensions. In the article solutions for combining several metamodel extensions and for the interoperability of metamodel extensions are presented. We also discuss how model transformations can use metamodel extensions.
Key words: metamodelling, metamodels, metamodel extensions, UML.
On
technical management of large power transmission networks; 18–37
Taivo Kangilaski
Abstract. This article considers problems which arise by technical management of large transmission networks and describes a technical software-related management system “Event Navigator”, developed at Eesti Energia AS.
Key words: transmission network, technical management, software.
Formation
of microstructure of spray-fused powder coatings; 38–51
Priit Kulu, Toomas Pihl, Kristi Tammjärv, and Petri Vuoristo
Abstract. The
paper describes a NiCrSiB self-fluxing alloys based system, containing
particles of tungsten carbide or those of WC-Co hardmetal from the used
hardmetal as hard phase, deposited by the spray and fusion processes. Flame and
laser spray fusions were used as coating technologies. The study focuses on
powder composition, hard phase grain size, processes of deposition, the effect
of the composition and process on the formation of the coating structure, and
on the evaluation of wear resistance of coatings. We discuss the dependence of
the wear resistance of spray-fused coatings on their structure and propose
structure criteria for coating selection. The “double cemented” matrix
structure of self-fluxing NiCrSiB based coatings, which contain WC-Co
particles, was found optimal in impact erosion wear conditions. The paper also
discusses the cost-effectiveness of coatings in application areas that are
sensitive to the cost and which prefer composite coatings based on low cost
recycled materials.
Key words: thermal spray, flame spray and fusion, laser spray and fusion,
composite coatings, impact erosion, wear.
Identification
of the wheelbase of road vehicles from wheel speed signals;
52–57
Péter Frank and Ansgar Fries
Abstract. Electronically
controlled brake systems are nowadays widely used in road vehicles. The control
systems consist of sensors, actuators, and of the electronic control unit. To
reduce the number of system components is a permanent market need. Therefore
the intelligence of the control software should be improved. One direction of
improvement is the implementation of adaptive algorithms. The latter allow to
renounce some pre-programmed parameters. The paper presents a simple method for
the identification of the wheelbase of road vehicles by evaluating the wheel
speed signals only. The method uses the correlation between noisy speed signals
of wheels running on the same road track one after another over a bump.
Measurements carried out on heavy trucks show the practical value of the
method.
Key words: electronically controlled brake system, road excitation, parameter
identification, correlation.
IN MEMORIAM
Boris Tamm; 58–59
Instructions to authors; 60–62
Copyright Transfer Agreement; 63