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 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.

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.

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 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 Multiscale representation of simulated time

SIMULATION ◽  
2017 ◽  
Vol 94 (6) ◽  
pp. 519-558 ◽  
Author(s):  
Rhys Goldstein ◽  
Azam Khan ◽  
Olivier Dalle ◽  
Gabriel Wainer
Keyword(s):  
Multiscale Modeling ◽  
Discrete Event ◽  
Limited Range ◽  
System Specification ◽  
Data Types ◽  
Rounding Errors ◽  
Time Representation ◽  
Event Simulation ◽  
Precision Level ◽  
Event Times

To better support multiscale modeling and simulation, we present a multiscale time representation consisting of data types, data structures, and algorithms that collectively support the recording of past events and scheduling of future events in a discrete event simulation. Our approach addresses the drawbacks of conventional time representations: limited range in the case of 32- or 64-bit fixed-point time values; problematic rounding errors in the case of floating-point numbers; and the lack of a universally acceptable precision level in the case of brute force approaches. The proposed representation provides both extensive range and fine resolution in the timing of events, yet it stores and manipulates the majority of event times as standard 64-bit numbers. When adopted for simulation purposes, the representation allows a domain expert to choose a precision level for his/her model. This time precision is honored by the simulator even when the model is integrated with other models of vastly different time scales. Making use of C++11 programming language features and the Discrete Event System Specification formalism, we implemented a simulator to test the time representation and inform a discussion on its implications for collaborative multiscale modeling efforts.

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.

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 MIX DEL PRODUCTO ÓPTIMO USANDO ALGORITMOS GENÉTICOS

2019 ◽  
pp. 67-69
Keyword(s):  
Genetic Algorithm ◽  
Genetic Algorithms ◽  
Discrete Event Simulation ◽  
A Priori ◽  
Discrete Event ◽  
Activity Based Costing ◽  
Product Mix ◽  
System Activity ◽  
Event Simulation ◽  
Model Combining

MIX DEL PRODUCTO ÓPTIMO USANDO ALGORITMOS GENÉTICOS MIX OF THE OPTIMUM PRODUCT USING GENETIC ALGORITHM Job Daniel Gamarra Moreno, Abraham Esteban Gamarra Moreno, Juan Gamarra Moreno Facultad de Ingeniería de Sistemas, Universidad Nacional del Centro del Perú - Huancayo DOI: https://doi.org/10.33017/RevECIPeru2004.0019/ RESUMEN Mix de producto óptimo significa determinar la cantidad de productos a producir para maximizar la ganancia. Para determinar el mix de producto óptimo de la Cooperativa Industrial Manufacturas del Centro de la ciudad de Huancayo, la empresa textil más importante de la región Andrés A. Cáceres, se ha construido el modelo híbrido que combina la simulación de eventos discretos y con los algoritmos genéticos. La simulación de eventos discretos se utiliza para inferir el costo unitario indirecto de cada producto debido al empleo de un sistema de costos basado en actividades. Para aplicar un sistema de costos basado en actividades se requiere información a posteriori, pero se puede conocerlo (aproximarlo) a priori aplicando la simulación de eventos discretos. Los algoritmos genéticos determinan el mix del producto óptimo que maximiza la utilidad. Estos algoritmos genéticos utilizan la codificación de valor para los cromosomas e incluyen técnicas para la solución de problemas con restricciones lineales. El mix de producto óptimo obtenido con el modelo disminuye las pérdidas con respecto al mix utilizado en el primer semestre, de aquellos productos cuyo costo unitario es superior a su precio, en un 43% e incrementan la utilidad en 123%. Palabras claves: Algoritmos genéticos, mix del producto, simulación de eventos discretos, costo basado en actividades. ABSTRACT Optimal product-mix means to determine the quantity of products to produce to maximize the gain. To determine the optimal product-mix of the Cooperativa Industrial Manufacturas del Centro from Huancayo city, the most important textile company in the region Andrés A. Cáceres, it has been built a hybrid model combining the discrete-event simulation and the genetic algorithms. The discrete-event simulation is used to infer the indirect unitary cost of each product due to the use of a system activity-based costing. To apply a system activity-based costing the posteriori information is required to, but one can know it (to approach it) a priori applying the discrete-event simulation. The genetic algorithms determine the optimal product-mix that maximizes the utility. These genetic algorithms use the code of value for the chromosomes and they include techniques for the solution of problems with lineal restrictions. The optimal product-mix obtained with the model decrease the losses of the product-mix used in the first semester, of those products whose unitary cost is greater than its price in 43% and they increase the utility in 123%. Keywords: Genetic algorithm, product-mix, discrete-event simulation, activity-based costing.

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