Exact scaling functions for one-dimensional stationary KPZ growth

We determine the stationary two-point correlation function of the one-dimensional KPZ equation through the scaling limit of a solvable microscopic model, the polynuclear growth model. The equivalence to a directed polymer problem with specific boundary conditions allows one to express the corresponding scaling function in terms of the solution to a Riemann-Hilbert problem related to the Painleve II equation. We solve these equations numerically with very high precision and compare our, up to numerical rounding exact, result with the prediction of Colaiori and Moore [1] obtained from the mode coupling approximation.Comment: 24 pages, 6 figures, replaced with revised versio

An Environment for DEVS-Based Multi-Formalism Modeling and Simulation in C++

This paper gives an introduction to a multiformalism modeling methodology which is based on the DEVS-formalism. Several extensions to DEVS like DEVS with conditional events, combined discrete continuous models, and variable structure coupled models are discussed. Model development is supported by a methodology which employs message sequence charts and hierarchical state transition diagrams. The C++- implementation of the modeling formalisms is presented. 1 Introduction and Motivation This tutorial is intended to give an introduction and overview into the C++-implemented object oriented modeling simulation environment currently being developed at our institute. The environment is based on the DEVS formalism and several extensions of it. Besides modular hierarchical DEVS modeling, also multi-formalism combined discrete/continuous (DEV&DESS) modeling and simulation is supported. Additionally, an extension of the DEVS formalisms for activity scanning is provided to ease discrete event si..

Object Oriented Modeling and Configuration of Simulation Programs

This paper deals with the question of reusability in simulation modeling of large scale systems. It discusses different approaches known from software engineering, in particular object oriented techniques and domain modeling, to enhance software reusability. Based on these ideas and on systems theory based simulation modeling, an environment is presented which supports modeling of application domains, interactive configuration of simulation models and automatic simulation program generation. 1 Introduction and Motivation Modeling and computer simulation of large scale systems, like transportation systems, traffic systems manufacturing systems, large scale networks and others, usually requires taking into account a huge number of different alternatives and parameters in system realization. However, often the variations in design of one system to another are relatively small. But the models and knowledge acquired in one simulation project are only used in the next project to a minor ext..

Domain wall fluctuations of the six-vertex model at the ice point

We report on Monte-Carlo simulations of the six-vertex model with domain wall boundary conditions. In thermal equilibrium such boundary conditions force a fluctuating line separating the disordered region from the perfectly ordered ones. Specifically we study the ice point at which all vertex weights are equal. With high precision the one-point fluctuations of the line are confirmed to be of order $N^{1/3}$ and governed by the Tracy-Widom distribution. Furthermore, the non-universal scaling coefficients are computed for a wide range of interaction strengths. A draft of this paper was completed in January 2019. We improved the presentation and updated references.Comment: 18 pages, 11 figure

On the Expressibility of Discrete Event Specified Systems

In this paper we address the question of the expressibility of discrete event specified systems (DEVS), i.e., we characterize the subclass of dynamical systems which can be homomorphically represented by DEVS models. We show that causal dynamical systems with piecewise constant input and output segment spaces are DEVSrepresentable. Moreover, DEVS-representable dynamical systems are closed under coupling, i.e., that a valid coupling of DEVS-representable dynamical systems is a DEVS-representable dynamical system. This justifies hierachical, modular construction of both DEVS models and real-world (continuous or discrete) counterpart systems. Furthermore, we investigate a subclass of dynamical systems in detail, viz., discretely interacting continuous systems with internal dynamics specified by differential equations. This class is important in the fast developing field of hybrid autonomous systems control and is amenable to high performance parallel/distributed discrete event simulation...

Concepts and Architecture of a Simulation Framework Based on the JavaBean Component Model

We report on a combination of system theoretic simulation modeling methodology with the JavaBeans component model as a basis for a component-based simulation framework. While system theory formalisms can serve as formal, mathematical foundations for modular, hierarchical modeling and simulation, the JavaBeans component model provides the appropriate implementation base. The result of the synergism is a powerful component-based simulation framework. In this paper we present the basic concepts and overall architecture of our JavaBeans modeling and simulation framework. We review the underlying system modeling formalisms for simulation modeling, sketch the layered architecture of the framework, and show elementary simulation programming and interface-based, hierarchical coupling of simulation components in more detail. Finally, we show the current state of implementation and demonstrate how simulation model can be developed using standard bean builder tools