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 UNIFIED TREATMENT OF LOCAL THEORY OF NFDES WITH INFINITE DELAY

1991 ◽  
Vol 22 (1) ◽  
pp. 51-72
Author(s):  
JIANHONG WU
Keyword(s):  
Phase Space ◽  
Infinite Delay ◽  
Sufficient Conditions ◽  
Local Theory ◽  
Fading Memory ◽  
Uniqueness Of Solutions ◽  
Condi Tions ◽  
Special Cases ◽  
Memory Characteristic ◽  
Well Posed

The present paper gives a unified treatment of the local theory of NFDEs with infinite delay on a class of comparatively comprehensive phase spaces which contain admissible phase spaces and BC space as special cases. Condi- tions and assumptions are imposed on two functionals defining the equation, and therefore independent of the structure and properties of phase spaces. This al- lows us to determine phase spaces and sufficient conditions guaranteeing existence and uniqueness of solutions according to the property of the equation at hand as opposed to preassign a phase space to dictate the conditions. An example will be given to show how to choose the phase space according to the fading memory characteristic of Volterra integrodifferential equations so that the Cauchy initial value problem is well posed.

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 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.

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.

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 Communication Analysis of Network-Centric Warfare via Transformation of System of Systems Model into Integrated System Model Using Neural Network

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Bong Gu Kang ◽  
Kyung-Min Seo ◽  
Tag Gon Kim
Keyword(s):  
Execution Time ◽  
Discrete Event ◽  
System Of Systems ◽  
Integrated System ◽  
Network System ◽  
System Specification ◽  
Discrete Events ◽  
Communication Analysis ◽  
Systems Model ◽  
Devs Formalism

Communication system in the network-centric warfare (NCW) has been analyzed from the perspective of the system of systems (SoS), which consists of a combat system and a network system so that the two reflect each other’s effects. However, this paradoxically causes a prolonged execution time. To solve this problem, this paper proposes an advanced integrated modeling method for the communication analysis in the NCW via the transformation of the SoS, which reduces the simulation execution time while ensuring the accuracy of the communication effects. The proposed models mainly cover interentity traffic and intraentity mobility developed in the form of feed-forward neural networks to guarantee two-way interactions between the combat system and the network system. Because they are characterized as discrete events, the proposed models are designed with the discrete-event system specification (DEVS) formalism. The experimental results show that the proposed transformation reduced an error by 6.40% compared to the existing method and reduced the execution time 3.78-fold compared to the SoS-based NCW simulation.

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.

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