In 1994, Alur and Dill introduced timed automata as a simple mathematical model for modelling the behaviour of real-time systems. In this thesis, we extend timed automata with weights. More detailed, we equip both the states and transitions of a timed automaton with weights taken from an appropriate mathematical structure. The weight of a transition determines the weight for taking this transition, and the weight of a state determines the weight for letting time elapse in this state. Since the weight for staying in a state depends on time, this model, called weighted timed automata, has many interesting applications, for instance, in operations research and scheduling. We give characterizations for the behaviours of weighted timed automata in terms of rational expressions and logical formulas. These formalisms are useful for the specification of real-time systems with continuous resource consumption. We further investigate the relation between the behaviours of weighted timed automata and timed automata. Finally, we present important decidability results for weighted timed automata.

In 1994, Alur and Dill introduced timed automata as a simple mathematical model for modelling the behaviour of real-time systems. In this thesis, we extend timed automata with weights. More detailed, we equip both the states and transitions of a timed automaton with weights taken from an appropriate mathematical structure. The weight of a transition determines the weight for taking this transition, and the weight of a state determines the weight for letting time elapse in this state. Since the weight for staying in a state depends on time, this model, called weighted timed automata, has many interesting applications, for instance, in operations research and scheduling. We give characterizations for the behaviours of weighted timed automata in terms of rational expressions and logical formulas. These formalisms are useful for the specification of real-time systems with continuous resource consumption. We further investigate the relation between the behaviours of weighted timed automata and timed automata. Finally, we present important decidability results for weighted timed automata.

Quantitative aspects of systems, like the maximal consumption of resources, can be modeled by weighted automata. The usual approach is to weight transitions with elements of a semiring and to define the behavior of the weighted automaton by mul- tiplying the transition weights along a run. In this thesis, we define and investigate a new class of weighted automata over unranked trees which are defined over valuation monoids. By turning to valuation monoids we use a more general cost model: the weight of a run is now determined by a global valuation function. Besides the binary cost functions implementable via semirings, valuation functions enable us to cope with average and discounting. We first investigate the supports of weighted unranked tree automata over valuation monoids, i.e., the languages of all words which are evalu- ated to a non-zero value. We will furthermore consider the support of several other weighted automata models over different structures, like words and ranked trees. Next we prove a Nivat-like theorem for the new weighted unranked tree automata. More- over, we give a logical characterization for them. We show that weighted unranked tree automata are expressively equivalent to a weighted MSO logic for unranked trees. This solves an open problem posed by Droste and Vogler. Finally, we present a Kleene- type result for weighted ranked tree automata over valuation monoids.

Quantitative aspects of systems, like the maximal consumption of resources, can be modeled by weighted automata. The usual approach is to weight transitions with elements of a semiring and to define the behavior of the weighted automaton by mul- tiplying the transition weights along a run. In this thesis, we define and investigate a new class of weighted automata over unranked trees which are defined over valuation monoids. By turning to valuation monoids we use a more general cost model: the weight of a run is now determined by a global valuation function. Besides the binary cost functions implementable via semirings, valuation functions enable us to cope with average and discounting. We first investigate the supports of weighted unranked tree automata over valuation monoids, i.e., the languages of all words which are evalu- ated to a non-zero value. We will furthermore consider the support of several other weighted automata models over different structures, like words and ranked trees. Next we prove a Nivat-like theorem for the new weighted unranked tree automata. More- over, we give a logical characterization for them. We show that weighted unranked tree automata are expressively equivalent to a weighted MSO logic for unranked trees. This solves an open problem posed by Droste and Vogler. Finally, we present a Kleene- type result for weighted ranked tree automata over valuation monoids.

In this thesis, we investigate weighted tree automata with storage theoretically. This model generalises finite state automata in three dimensions: (i) from words to trees, (ii) by using an arbitrary storage type in addition to a finite-state control, and (iii) by considering languages in a quantitative setting using a weight structure.

- Rückblick Simulation-News in Creo 1.0 & Creo 2.0 - Ausblick Simulation-News in Creo 3.0 - Gewichtete Verbindungen: „Tips & Tricks“ mit konkreten Beispielen: o Lagersteifigkeiten (z.B. Wälzlager) o Mechanismus Verbindungen (Dreh-, Schub-, Zylinder, .... Gelenke) o Vorgespannte Schrauben (mit Schalen-/Balken-Elementen) o Aufbringung einer momentfreien Zwangsverschiebung o „Gesamtlast auf Punkt“: Messen der Punktverschiebung o Verbinden von Massen-Elementen o Verhindern von Singularitäten - Live-Präsentation in Creo 2.0 o Lagersteifigkeiten (z.B. Wälzlager) o Mechanismus Verbindungen (Dreh-, Schub-, Zylinder, .... Gelenke)

Zugl.: Stuttgart, Univ., Diss., 2008. / Druckausg. beim Shaker Verl., Aachen erschienen.

In this thesis, three methods are investigated to express context-free tree languages by regular tree grammars. The first method is a characterization. We show restrictions to context-free tree grammars such that, for each restricted context-free tree grammar, a regular tree grammar can be constructed that induces the same tree language. The other two methods are approximations. An arbitrary context-free tree language can be approximated by a regular tree grammar with a restricted pushdown storage. Furthermore, we approximate weighted context-free tree languages, induced by weighted linear nondeleting context-free tree grammars, by showing how to approximate optimal weights for weighted regular tree grammars.

In this thesis, three methods are investigated to express context-free tree languages by regular tree grammars. The first method is a characterization. We show restrictions to context-free tree grammars such that, for each restricted context-free tree grammar, a regular tree grammar can be constructed that induces the same tree language. The other two methods are approximations. An arbitrary context-free tree language can be approximated by a regular tree grammar with a restricted pushdown storage. Furthermore, we approximate weighted context-free tree languages, induced by weighted linear nondeleting context-free tree grammars, by showing how to approximate optimal weights for weighted regular tree grammars.

- Rückblick Simulation-News in Creo 1.0 & Creo 2.0 - Ausblick Simulation-News in Creo 3.0 - Gewichtete Verbindungen: „Tips & Tricks“ mit konkreten Beispielen: o Lagersteifigkeiten (z.B. Wälzlager) o Mechanismus Verbindungen (Dreh-, Schub-, Zylinder, .... Gelenke) o Vorgespannte Schrauben (mit Schalen-/Balken-Elementen) o Aufbringung einer momentfreien Zwangsverschiebung o „Gesamtlast auf Punkt“: Messen der Punktverschiebung o Verbinden von Massen-Elementen o Verhindern von Singularitäten - Live-Präsentation in Creo 2.0 o Lagersteifigkeiten (z.B. Wälzlager) o Mechanismus Verbindungen (Dreh-, Schub-, Zylinder, .... Gelenke)