scholarly journals Modelling Dynamics of a Log-Yard through Discrete-Event Mathematics

Forests ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 155 ◽  
Author(s):  
Kalvis Kons ◽  
Pedro La Hera ◽  
Dan Bergström
Keyword(s):  
Model Calibration ◽  
Discrete Event ◽  
Pulp Mill ◽  
Discrete Events ◽  
Process Data ◽  
Sequence Of Events ◽  
Machine Operators ◽  
Calibration Techniques ◽  
Machine Operator ◽  
Two Alternatives

This article deals with the topic of modelling the log-yard of one of our industry partners. To this end, our framework is based on discrete-events modelling (DEM), as consequence that many stages of the process run as a sequence of events. The sequence starts when trucks, trains or ships arrive loaded with logs to the log-yard. A machine unloads these logs and accumulates them in different storage areas. Consequently, a machine transports logs from these areas to the pulp mill, thus finishing the process. As using probability density functions is the core concept of DEM, the necessary process data to build these PDFs have been partly provided by the company. Other necessary data have been acquired through time studies, and by defining operational requirements. The company data tell when trucks, trains, or ships arrive to the log-yard, and the amount of volume they carry. The objective is to develop the necessary formulations, model calibration techniques, and software, such that computer simulations reproduce the quantities observed in these data. To this end, this work suggests two alternatives to analyse the data itself. These two alternatives lead to two different models: (1) The first being a hybrid model, in the sense that it involves the events in the process, and the logic decisions taken by machine operators for handling the incoming load, and (2) the second containing only the main mathematical essence of the process. After running 100 simulations, both mathematical models show that the simulated values for input and output, in terms of transport units and their volume, differ only by less than 3% compared to company data. The first model has also shown the ability to replicate the decision making that a machine operator undergoes for driving the logs to the storage areas, and from there to the mill. Therefore, the framework adopted provides the necessary mathematical tools and data analysis to model the log-yard and obtain highly reliable results via simulations.

Decision making at unsignalized inner city intersections using discrete events systems

2022 ◽  
Vol 0 (0) ◽  
Author(s):  
Hannes Weinreuter ◽  
Balázs Szigeti ◽  
Nadine-Rebecca Strelau ◽  
Barbara Deml ◽  
Michael Heizmann
Keyword(s):  
Inner City ◽  
Road Safety ◽  
Autonomous Vehicles ◽  
Discrete Event ◽  
Autonomous Driving ◽  
Simulation Environment ◽  
Discrete Events ◽  
Real World Data ◽  
Event System ◽  
Discrete Events Systems

Abstract Autonomous driving is a promising technology to, among many aspects, improve road safety. There are however several scenarios that are challenging for autonomous vehicles. One of these are unsignalized junctions. There exist scenarios in which there is no clear regulation as to is allowed to drive first. Instead, communication and cooperation are necessary to solve such scenarios. This is especially challenging when interacting with human drivers. In this work we focus on unsignalized T-intersections. For that scenario we propose a discrete event system (DES) that is able to solve the cooperation with human drivers at a T-intersection with limited visibility and no direct communication. The algorithm is validated in a simulation environment, and the parameters for the algorithm are based on an analysis of typical human behavior at intersections using real-world data.

Software for Queueing Analysis

2018 ◽  
pp. 255-291
Keyword(s):  
Queueing Networks ◽  
Discrete Event ◽  
Queueing Network ◽  
Queueing Analysis ◽  
Discrete Events ◽  
Technical Literature ◽  
Event Simulation ◽  
Statistical Program ◽  
Service Times ◽  
Waiting Lines

Chapter 8 gives a brief discussion of computer simulation for discrete events. The chapter lists software programs in the technical literature that outline programs for the simulation of discrete events, both of commercial origin and free programs. In addition to the lists submitted, the authors present specialized packages for analysis and simulation of waiting lines in the R language. Statistical considerations are presented, which must be taken into account when obtaining data from simulations in situations of waiting lines. Chapter 8 presents three packages of the statistical program R: the “queueing” analysis package provides versatile tools for analysis of birth- and death-based Markovian queueing models and single and multiclass product-form queueing networks; “simmer” package is a process-oriented and trajectory-based discrete-event simulation (DES) package for R; and, the purpose of the “queuecomputer” package is to calculate, deterministically, the outputs of a queueing network, given the arrival and service times of all the customers. It also uses simulation for the implementation of a method for the calculation of queues with arbitrary arrival and service times. For each theme, the authors show the use of the packages in R.

scholarly journals An Approach for Manufacturing Process Representation in Product Lifecycle Management

2013 ◽  
Vol 572 ◽  
pp. 239-244 ◽  
Author(s):  
Navid Shariatzadeh ◽  
Gunilla Sivard ◽  
Lars Lindberg
Keyword(s):  
Manufacturing Process ◽  
Discrete Event ◽  
Product Lifecycle Management ◽  
Process Data ◽  
Event Simulation ◽  
Process Representation ◽  
Efficient Management ◽  
Generic Data ◽  
Flow Information ◽  
Lifecycle Management

Current PLM systems have concentrated on product design, not on manufacturing engineering with its development of e.g. Material flows and layouts. This paper proposes an approach to describe how to represent the main required manufacturing process data using ontologies together with generic data standards. This approach makes it possible to develop translations between different software, and also providing users with the meaning of different concepts. It contributes to an efficient management of manufacturing information, with a focus on the material flow information as used in Discrete Event Simulation - DES.

Multi-Objective Engineering Design Via Computer Model Calibration

2020 ◽  
Vol 143 (5) ◽  
Author(s):  
Carl Ehrett ◽  
D. Andrew Brown ◽  
Evan Chodora ◽  
Christopher Kitchens ◽  
Sez Atamturktur
Keyword(s):  
Computer Model ◽  
Model Calibration ◽  
Material Design ◽  
Fine Tuning ◽  
Tuning Parameter ◽  
Design Problems ◽  
Multi Objective ◽  
Performance Targets ◽  
Calibration Techniques ◽  
Parameter Values

Abstract Computer model calibration typically operates by fine-tuning parameter values in a computer model so that the model output faithfully predicts reality. By using performance targets in place of observed data, we show that calibration techniques can be repurposed for solving multi-objective design problems. Our approach allows us to consider all relevant sources of uncertainty as an integral part of the design process. We demonstrate our proposed approach through both simulation and fine-tuning material design settings to meet performance targets for a wind turbine blade.

scholarly journals WORKING CONDITIONS FOR EMPLOYEES OF THE ENTERPRISE OF WOODWORKING INDUSTRY

2019 ◽  
Vol 96 (4) ◽  
pp. 344-346 ◽  
Author(s):  
N. N. Petrova ◽  
V. S. Panshina ◽  
A. P. Figurovsky ◽  
I. O. Topanov
Keyword(s):  
Working Conditions ◽  
The Body ◽  
Labor Process ◽  
Finish Line ◽  
The Third ◽  
Main Work ◽  
Number Of Factors ◽  
Machine Operators ◽  
Spray Booth ◽  
Machine Operator

The hygienic assessment of working conditions at the modern furniture company showed such conditions at main work places are referred to the third class of the first and second degrees of the hazard and danger. The most adverse working conditions (3 class, 2 degree) are typical for operators of woodworking machines, machine operator in a spray booth for the edges of the sorter-stacker at the discharge conveyor line trim boards and spray the frames, the sorter-stacker at the feed conveyor panels of finish line rollers. Man-made noise, low lightness of working places, and the hardness of the labor process are most harmful occupational factors. Implementation of paint operations on processing of furniture components is further accompanied by the air pollution of the working area by chemicals and exposure of the body of the worker to the heating microclimate of radiation-convection type. Most of workplaces are characterized by summing the classes of working conditions on a number of factors. It indicates to their complex impact on the body of the worker. The assessment of the risk of occupational hearing loss showed the most probability of its development in machine operators and packers.

scholarly journals Proposal for Medical Data Transmission in Healthcare Systems

2020 ◽  
Vol 4 (3) ◽  
pp. 580-580
Author(s):  
Reinaldo Padilha França
Keyword(s):  
Positive Impact ◽  
Signal Transmission ◽  
Discrete Event ◽  
Healthcare Systems ◽  
Background Information ◽  
Generation Process ◽  
Discrete Events ◽  
Computational Performance ◽  
System Memory ◽  
Waiting Periods

Background: Information systems used in hospitals are slow and consume a lot of system memory, facilitating crashes, impacting patients seeking consultation face long waiting periods by a medical specialist; Still considering that exchange patient data and medical consultations in system interconnected between hospitals, for scheduling of consultations may become even more latent.Methods: Aiming to solve such problems, the present study implements modeling with discrete-event technology applied to a healthcare system, modulating the signal transmitted with the DQPSK format, through the simulation environment, the Simulink of the MATLAB software, improving the transmission of data, through a pre-coding process of bits adopting discrete events in the signal before modulation.Results: This study aims to increase the information capacity for healthcare systems, bringing a new approach for signal transmission, undertaken in the discrete domain employing the discrete entities in the bit generation process, this use being the differential applied on the bit itself, in the physical layer, showing better computational performance regarding memory utilization related to compression of information, showing an improvement of 101.52%.Conclusion: The proposal developed has the properties of improving the capacity of hospital services and can increase the performance of the communication between all medical devices, this positive impact is the result that the data stream will consume fewer communication resources.

scholarly journals MODELING PREDICTIVE TRACKING CONTROL FOR MAX-PLUS LINEAR SYSTEMS IN MANUFACTURING

2020 ◽  
Vol 3 (2) ◽  
pp. 133-147
Author(s):  
Lathifatul Aulia ◽  
Widowati Widowati ◽  
R. Heru Tjahjana ◽  
Sutrisno Sutrisno
Keyword(s):  
Linear Systems ◽  
Production System ◽  
Tracking Control ◽  
Discrete Event Systems ◽  
Discrete Event ◽  
Process Flow ◽  
Sequence Of Events ◽  
Input And Output ◽  
Event System ◽  
Event Systems

Discrete event systems, also known as DES, are class of system that can be applied to systems having an event that occurred instantaneously and may change the state. It can also be said that a discrete event system occurs under certain conditions for a certain period because of the network that describes the process flow or sequence of events. Discrete event systems belong to class of nonlinear systems in classical algebra. Based on this situation, it is necessary to do some treatments, one of which is linearization process. In the other hand, a Max-Plus Linear system is known as a system that produces linear models. This system is a development of a discrete event system that contains synchronization when it is modeled in Max-Plus Algebra. This paper discusses the production system model in manufacturing industries where the model pays the attention into the process flow or sequence of events at each time step. In particular, Model Predictive Control (MPC) is a popular control design method used in many fields including manufacturing systems. MPC for Max-Plus-Linear Systems is used here as the approach that can be used to model the optimal input and output sequences of discrete event systems. The main advantage of MPC is its ability to provide certain constraints on the input and output control signals. While deciding the optimal control value, a cost criterion is minimized by determining the optimal time in the production system that modeled as a Max-Plus Linear (MPL) system. A numerical experiment is performed in the end of this paper for tracking control purposes of a production system. The results were good that is the controlled system showed a good performance.

Methodologies and Approaches in Discrete Event Simulation

2008 ◽  
pp. 1-35
Author(s):  
Evon M. O. Abu-Taieh ◽  
Asim Abdel Rahman El Sheikh
Keyword(s):  
Discrete Event ◽  
Activity Cycle ◽  
Scale Model ◽  
Discrete Events ◽  
Web Based ◽  
Event Simulation ◽  
Modeling Approaches ◽  
Continuous Models ◽  
Systems Simulation ◽  
Cycle Diagram

This chapter aims to give a comprehensive explanatory platform of simulation background. As this chapter comprises of four sections, it reviews simulation definitions, forms of models, the need for simulation, simulation approaches and modeling notations. Simulation definition is essential in order to set research boundaries. Moreover, the chapter discusses forms of models: scale model of the real system, or discrete and continuous models. Subsequently, the chapter states documentation of several reasons by different authors pertaining to the question of “why simulate?,” followed by a thorough discussion of modeling approaches in respect to general considerations. Simulation modeling approaches are discussed with special emphasis on the discrete events type only: process-interaction, event scheduling, and activity scanning, yet, a slight comparison is made between the different approaches. Furthermore, the chapter discusses modeling notations activity cycle diagram (ACD) with different versions of the ACD. Furthermore, the chapter discusses petri nets, which handle concurrent discrete events dynamic systems simulation. In addition, Monte Carlo simulation is discussed due to its important applications. Finally, the fourth section of this chapter reviews Web-based simulation, along with all three different types of object-oriented simulation and modeling.

Modern motor milestones

PEDIATRICS ◽  
1978 ◽  
Vol 62 (6) ◽  
pp. 1037-1038
Author(s):  
Lawrence R. Berger
Keyword(s):  
Child Development ◽  
Discrete Event ◽  
Discrete Events ◽  
Affluent Society ◽  
Motor Milestone

In child development circles, a motor milestone is a discrete event in a person's progressive mastery of control over the body's movements. To most parents, each milestone-sitting up without support, grasping a raisin between thumb and forefinger, holding a cup, taking the first step all by herself—is a joyous occasion in their child's life. Children of the seventies, however, exhibit a new set of motor milestones made possible by our affluent society. None of these is cause for celebration. The modern milestones are discrete events marking the child's progressive involvement with engine-driven vehicles. As early as 4 years of age, children may ride their first minibike.

Lower Memory Consumption for Data Transmission in Smart Cloud Environments With CBEDE Methodology

2020 ◽  
pp. 216-237
Author(s):  
Reinaldo Padilha França ◽  
Yuzo Iano ◽  
Ana Carolina Borges Monteiro ◽  
Rangel Arthur
Keyword(s):  
Data Transmission ◽  
Discrete Event ◽  
Discrete Events ◽  
Memory Consumption ◽  
Digital Platforms ◽  
Computational Performance ◽  
Consumer Benefits ◽  
Cloud Environments ◽  
Memory Utilization

Smart telecoms will deliver lasting improvements to business productivity and enduring consumer benefits that raise the quality of life by enabling telecommuting, telemedicine, entertainment, access to e-government, and a wealth of other online services. And we'll need next-generation digital platforms on which telecom providers can create and deliver all kinds of services. Therefore, this chapter develops a method of data transmission based on discrete event concepts. This methodology was named CBEDE. Using the MATLAB software, the memory consumption of the proposed methodology was evaluated, presenting the great potential to intermediate users and computer systems, ensuring speed, low memory consumption, and reliability. With the differential of this research, the use of discrete events applied in the physical layer of a transmission medium, the bit itself, being this to low-level of abstraction, the results show better computational performance related to memory utilization, showing an improvement of up to 79.89%.

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