This paper reports the results of a workshop held at ECOOP’99. The workshop was set up to find answers to questions fundamental to the definition of a semantics for the Unified Modelling Language. Questions examined the meaning of the term semantics in the context of UML; approaches to defining the semantics, including the feasibility of the meta-modelling approach; whether a single semantics i...

Designing and applying a domain specific modelling language appears to be quite simple: invent appropriate modelling elements and connectors, define their semantics in a legend and use them. The talk will show, that there are more aspects to consider and more steps to perform, and that it is necessary to deeply immerse into the domain in question. But the result is worth the effort. The work su...

This paper describes a number of key modeling issues for the development of tools for solving nonlinear discrete/continuous problems where logic/disjunctive constraints are included in the formulation. A generalized hybrid representation of these problems is presented. A comparison between Constraint logic programming (CLP) and generalized disjunctive programming (GDP) is established together w...

Bayesian analysis provides a convenient setting for the estimation of complex generalized additive regression models (GAMs). Since computational power has tremendously increased in the past decade it is now possible to tackle complicated inferential problems, e.g., with Markov chain Monte Carlo simulation, on virtually any modern computer. This is one of the reasons why Bayesian methods have be...

Formal modelling languages are powerful tools to systematically represent and analyze the properties of systems. A myriad of new modelling languages, as well as extensions of existing ones, are proposed every year. We may consider that a modelling language is useful if it allows to represent the critical aspects of systems in an expressive way. In particular, we require that the modelling langu...

The conventional wisdom expressed at several recent joint conferences and workshops on algebraic geometry and geometric modeling – Algebraic Geometry and Geometric Modeling 2002, Vilnius, Lithuania, The MSRI Workshop on Real Algebraic Geometry in Applications, Berkeley, 2004, and Algebraic Geometry and Geometric Modeling 2004, Nice, France – is that algebraic geometry has much to offer geometri...

Dissipative Hamiltonian (DH) systems are an important concept in energy based modeling of dynamical systems. One of the major advantages of the DH formulation is that system properties are encoded in an algebraic way. For instance, the algebraic structure of DH systems guarantees that the system is automatically stable. In this paper the question is discussed when a linear constant coefficient ...

In this work, we perform an extensive theoretical and experimental analysis of the characteristics five most prominent algebraic modelling languages (AMPL, AIMMS, GAMS, JuMP, Pyomo) systems supporting them. our comparison, evaluate how reviewed modern match current requirements. analysis, use a purpose-built test model library to benchmarks. We provide insights on which performed best features ...

Differential-algebraic equations (DAEs) present today the state-of-the-art in dynamical systems arising from automated modularized modeling in almost all areas of science and engineering. While the modeling becomes more and more convenient, the resulting models are typically not easy to treat with current numerical simulation, control and optimization methods. In many cases a reformulation of t...

This paper studies algebraic and geometric properties of curve–curve, curve– surface, and surface–surface bisectors. The computation is in general difficult since the bisector is determined by solving a system of nonlinear equations. Geometric considerations will help us to determine several distinguished curve and surface pairs which possess elementary computable bisectors. Emphasis is on lowd...