Metamodel-based formalization of DEVS atomic models

SIMULATION ◽  
2021 ◽  
pp. 003754972110456
Author(s):  
María Julia Blas ◽  
Silvio Gonnet
Keyword(s):  
Programming Languages ◽  
Formal Specification ◽  
Formal Model ◽  
Discrete Event ◽  
Theory And Practice ◽  
System Specification ◽  
Simulation Tools ◽  
Atomic Models ◽  
Devs Formalism ◽  
Definition Of

The Discrete-Event System Specification (DEVS) formalism is a modeling formalism based on systems theory that provides a general methodology for hierarchical construction of reusable models in a modular way. When concrete DEVS models are developed using programming languages, it is difficult to ensure they conform to their formal model. Hence, building an implementation of formal models in a way that ensures DEVS formalism correctness is not easy. In this paper, we improve the interplay of abstraction (i.e., formal specification) and concreteness (i.e., programming code implementation) in advancing the theory and practice of DEVS using a specific-designed metamodel. The main contribution is a novel conceptualization of classic DEVS with ports founded on existing approaches but that also includes new improved elements related to the definition of atomic models. That is, our metamodel includes all the concepts and relationships needed to define the formal specification of DEVS atomic models. This allows us to define instances of our conceptualization that comply with the DEVS formal specification. To instantiate our metamodel, we propose a computer-aided environment that has been developed using the Eclipse Modeling Project. As an example, we show how our metamodel can be used to define the classic “switch” model. As a conclusion, we discuss how the final metamodel can be used to support interoperability with DEVS simulation tools.

scholarly journals Towards an automatic model transformation mechanism from UML state machines to DEVS models

2015 ◽  
Author(s):  
Ariel González ◽  
Carlos Luna ◽  
Roque Cuello ◽  
Marcela Pérez ◽  
Marcela Daniele
Keyword(s):  
Modeling And Simulation ◽  
Model Transformation ◽  
Discrete Event ◽  
State Machines ◽  
System Specification ◽  
Transformation Mechanism ◽  
Simulation Tools ◽  
Model Driven ◽  
Uml State Machines ◽  
Devs Formalism

The development of complex event-driven systems requires studies and analysis prior to deployment with the goal of detecting unwanted behavior. UML is a language widely used by the software engineering community for modeling these systems through state machines, among other mechanisms. Currently, these models do not have appropriate execution and simulation tools to analyze the real behavior of systems. Existing tools do not provide appropriate libraries (sampling from a probability distribution, plotting, etc.) both to build and to analyze models. Modeling and simulation for design and prototyping of systems are widely used techniques to predict, investigate and compare the performance of systems. In particular, the Discrete Event System Specification (DEVS) formalism separates the modeling and simulation; there are several tools available on the market that run and collect information from DEVS models. This paper proposes a model transformation mechanism from UML state machines to DEVS models in the Model-Driven Development (MDD) context, through the declarative QVT Relations language, in order to perform simulations using tools, such as PowerDEVS. A mechanism to validate the transformation is proposed. Moreover, examples of application to analyze the behavior of an automatic banking machine and a control system of an elevator are presented.

Practical aspects of the DesignDEVS simulation environment

SIMULATION ◽  
2017 ◽  
Vol 94 (4) ◽  
pp. 301-326 ◽  
Author(s):  
Rhys Goldstein ◽  
Simon Breslav ◽  
Azam Khan
Keyword(s):  
Systems Engineering ◽  
Best Practice ◽  
Discrete Event ◽  
State Transitions ◽  
System Specification ◽  
Development Environment ◽  
Simulation Tools ◽  
Model Code ◽  
Strict Enforcement ◽  
Devs Formalism

DesignDEVS is a simulation development environment based on the Discrete Event System Specification (DEVS) formalism. This paper provides an in-depth overview of the software while focusing on the practical considerations influencing its design. Practitioners who stand to benefit from systems engineering will approach formalism-based simulation tools with little knowledge of the underlying theory. It is therefore important that theoretical principles, such as the separation of model and simulator, be emphasized by the user interface. Other practical aspects of DesignDEVS include the simplicity of atomic model code, a focus on coupling for collaboration purposes, the enforcement of essential modeling constraints, and a reliance on best practices in cases where strict enforcement might inconvenience users. In DesignDEVS, an issue we refer to as the Insidious Pointer Problem is aggressively tackled through run-time error handling. By contrast, the separation of output values from state transitions is left as a best practice for the sake of user convenience. The design decisions explained in this paper are relevant to developers of other formalism-based tools seeking widespread adoption of scalable modeling and simulation practices.

scholarly journals Emergence at the Fundamental Systems Level: Existence Conditions for Iterative Specifications

2016 ◽  
Author(s):  
Bernard Zeigler ◽  
Alexandre Muzy
Keyword(s):  
Discrete Event ◽  
Sufficient Conditions ◽  
System Specification ◽  
Global State ◽  
Uniqueness Of Solutions ◽  
Fundamental Level ◽  
Mathematical System ◽  
Special Cases ◽  
Fundamental Systems ◽  
Devs Formalism

Conditions under which compositions of component systems form a well-defined system-of-systems here are formulated at a fundamental level. Statement of what defines a well-defined composition and sufficient conditions guaranteeing such a result offers insight into exemplars that can be found in special cases such as differential equation and discrete event systems. For any given global state of a composition, two requirements can be stated informally as: 1) the system can leave this state, i.e., there is at least one trajectory defined that starts from the state, and 2) the trajectory evolves over time without getting stuck at a point in time. Considered for every global state, these conditions determine whether the resultant is a well-defined system and if so, whether it is non-deterministic or deterministic. We formulate these questions within the framework of iterative specifications for mathematical system models that are shown to be behaviorally equivalent to the Discrete Event System Specification (DEVS) formalism. This formalization supports definitions and proofs of the afore-mentioned conditions. Implications are drawn at the fundamental level of existence where the emergence of a system from an assemblage of components can be characterized. We focus on systems with feedback coupling where existence and uniqueness of solutions is problematic.

scholarly journals Special Issue on the Theory and Practice of Differential Privacy

2017 ◽  
Vol 7 (2) ◽  
Author(s):  
Marco Gaboardi ◽  
Chris J. Skinner
Keyword(s):  
Data Analysis ◽  
Programming Languages ◽  
Differential Privacy ◽  
International Workshop ◽  
Theory And Practice ◽  
Release Mechanism ◽  
Special Issue ◽  
Research Areas ◽  
Recent Developments ◽  
Definition Of

This special issue presents papers based on contributions to the first international workshop on the “Theory and Practice of Differential Privacy” (TPDP) held in London, UK, 18 April 2015, as part of the European joint conference on Theory And Practice of Software (ETAPS). Differential privacy is a mathematically rigorous definition of the privacy protection provided by a data release mechanism: it offers a strong guaranteed bound on what can be learned about a user as a result of participating in a differentially private data analysis. Researchers in differential privacy come from several areas of computer science, including algorithms, programming languages, security, databases and machine learning, as well as from several areas of statistics and data analysis. The workshop was intended to be an occasion for researchers from these different research areas to discuss the recent developments in the theory and practice of differential privacy. The program of the workshop included 10 contributed talks, 1 invited speaker and 1 joint invited speaker with the workshop “Hot Issues in Security Principles and Trust” (HotSpot 2016). Participants at the workshop were invited to submit papers to this special issue. Six papers were accepted, most of which directly reflect talks presented at the workshop

scholarly journals A DEVS-based engine for building digital quadruplets

SIMULATION ◽  
2021 ◽  
pp. 003754972110031
Author(s):  
Daniella Niyonkuru ◽  
Gabriel Wainer
Keyword(s):  
Real Time ◽  
Formal Model ◽  
Formal Analysis ◽  
Discrete Event ◽  
Physical World ◽  
Common Mechanism ◽  
The Real ◽  
Event Modeling ◽  
Definition Of ◽  
Time Systems

Development of Embedded Real-Time Systems is prone to error, and developing bug-free applications is expensive and no guarantees can be provided. We introduce the concept of Digital Quadruplet which includes: a 3D virtual representation of the physical world (a Digital Twin), a Discrete-Event formal model of the system of interest (called the “Digital Triplet”), which can be used for formal analysis as well as simulation studies, and a physical model of the real system under study for experimentation (called the “Digital Quadruplet”). We focus on the definition of the idea of a Digital Quadruplet and how to make these four apparati consistent and reusable. To do so, we use the Discrete-Event formal model as a center for both simulation and execution of the real-time embedded components with timing constraints, as well as a common mechanism for interfacing with the digital counterparts, providing model continuity throughout the process. Here we focus on a principal part of the Digital Quadruplet idea: the provision of an environment to allow models to be used for simulation (in virtual time), visualization, or execution in real-time. A Discrete-EVent Systems specifications (DEVS) kernel runs on bare-metal hardware platforms, avoiding the use of an Operating RTOS in the platform, and the combination with discrete-event modeling engineering.

The DEVS Formalism

2013 ◽  
pp. 62-102
Author(s):  
Rhys Goldstein ◽  
Gabriel A. Wainer ◽  
Azam Khan
Keyword(s):  
Formal Specification ◽  
Discrete Event ◽  
Simulation Models ◽  
Object Oriented Programming ◽  
Event Simulation ◽  
The Core ◽  
Modular Model ◽  
Core Concepts ◽  
Devs Formalism ◽  
The Relationship

The DEVS formalism is a set of conventions introduced in 1976 for the specification of discrete event simulation models. This chapter explains the core concepts of DEVS by applying the formalism to a single ongoing example. First, the example is introduced as a set of informal requirements from which a formal specification is to be developed. Readers are then presented with alternative sets of modeling conventions which, lacking the DEVS formalism’s approach to representing state, prove inadequate for the example. The chapter exploits the DEVS formalism’s support for modular model design, as the system in the example is specified first in parts and later as a combination of those parts. The concept of legitimacy is demonstrated on various model specifications, and the relationship between DEVS and both object-oriented programming and parallel computing is discussed.

scholarly journals Discrete event simulation of Maglev transport considering traffic waves

2014 ◽  
Vol 1 (4) ◽  
pp. 233-242 ◽  
Author(s):  
Moo Hyun Cha ◽  
Duhwan Mun
Keyword(s):  
A Priori ◽  
Discrete Event ◽  
System Specification ◽  
Simulation Technology ◽  
Event Simulation ◽  
Train Operation ◽  
Railway Passenger ◽  
Devs Formalism ◽  
Traffic Wave ◽  
Demand Changes

Abstract A magnetically levitated vehicle (Maglev) system is under commercialization as a new transportation system in Korea. The Maglev is operated by an unmanned automatic control system. Therefore, the plan of train operation should be carefully established and validated in advance. In general, when making a train operation plan, statistically predicted traffic data is used. However, a traffic wave often occurs in real train service, and demand-driven simulation technology is required to review a train operation plan and service quality considering traffic waves. We propose a method and model to simulate Maglev operation considering continuous demand changes. For this purpose, we employed a discrete event model that is suitable for modeling the behavior of railway passenger transportation. We modeled the system hierarchically using discrete event system specification (DEVS) formalism. In addition, through implementation and an experiment using the DEVSim++ simulation environment, we tested the feasibility of the proposed model. Our experimental results also verified that our demand-driven simulation technology can be used for a priori review of train operation plans and strategies.

scholarly journals A conceptual framework for the modelling and simulation of social systems

DYNA ◽  
2020 ◽  
Vol 87 (212) ◽  
pp. 189-198
Author(s):  
Gabriel Awad ◽  
Hernán Darío ÁLVAREZ ZAPATA
Keyword(s):  
Conceptual Framework ◽  
Social Systems ◽  
Discrete Event ◽  
Modelling And Simulation ◽  
System Specification ◽  
Modelling Language ◽  
Event System ◽  
Systems Modelling ◽  
Devs Formalism ◽  
Critical Literature

This paper presents a conceptual framework for the modelling and simulation of properties, interactions and processes of social systems based on computational templates using discrete event system specification (DEVS) formalism and OMG Systems Modelling Language (SysML) diagrams. No antecedents of this combination were found in the literature, and so this is one of the contributions of this paper. Additionally, this article explains how the principles and rules of SysML can be applied to the analysis of social systems. An example of the proposed framework based on a basic Agent_Zero model is shown. The conceptual framework was built based on a critical literature review, and included new additional elements to create a complete but simple conceptual framework. The codes for the simulations were written in Python 3.

scholarly journals Discrete Event Simulation-Based Reliability Evaluation of a Traffic Signal Controller

2018 ◽  
Vol 2018 ◽  
pp. 1-5
Author(s):  
Joong Soon Jang ◽  
Sang C. Park
Keyword(s):  
Discrete Event ◽  
Reliability Evaluation ◽  
Vital Role ◽  
Traffic Signal ◽  
Evaluation Methodology ◽  
System Specification ◽  
Event Simulation ◽  
Simulation Based ◽  
Maintenance Policies ◽  
Devs Formalism

A mission reliability evaluation methodology for a signal traffic controller is presented in this paper. To develop the new evaluation methodology, this paper combines the Discrete Event System Specification (DEVS) formalism which has been popular in manufacturing area for three reasons: (1) its features compatible with the object-oriented modeling; (2) its rigorous formal definition; and (3) its support for the specifications of discrete event models in a hierarchical and modular manner. By using the DEVS formalism, we construct a simulation model which takes into account not only the characteristics of a traffic signal controller but also the operating environment. Once a model is constructed, it is possible to perform simulation experiments. The proposed methodology computes the mission reliability of a traffic signal controller by using a simulation record, and this information plays a vital role in preparing optimized maintenance policies that maximize availability or minimize life cycle costs.

The high level language for system specification: A model-driven approach to systems engineering

2016 ◽  
Vol 07 (01) ◽  
pp. 1641003 ◽  
Author(s):  
Hamzat Olanrewaju Aliyu ◽  
Oumar Maïga ◽  
Mamadou Kaba Traoré
Keyword(s):  
Systems Engineering ◽  
Discrete Event ◽  
Discrete Event System ◽  
High Level Language ◽  
System Specification ◽  
Model Driven ◽  
Event System ◽  
Visual Formalisms ◽  
Devs Formalism ◽  
High Level

We present HiLLS (High Level Language for System Specification), a graphical formalism that allows to specify Discrete Event System (DES) models for analysis using methodologies like simulation, formal methods and enactment. HiLLS’ syntax is built from the integration of concepts from System Theory and Software Engineering aided by simple concrete notations to describe the structural and behavioral aspects of DESs. This paper provides the syntax of HiLLS and its simulation semantics which is based on the Discrete Event System Specification (DEVS) formalism. From DEVS-based Modeling and Simulation (M&S) perspective, HiLLS is a platform-independent visual language with generic expressions that can serve as a front-end for most existing DEVS-based simulation environments with the aid of Model-Driven Engineering (MDE) techniques. It also suggests ways to fill some gaps in existing DEVS-based visual formalisms that inhibit complete specification of the behavior of complex DESs. We provide a case study to illustrate the core features of the language.

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