scholarly journals SUBSTANTIATION OF THE TECHNOLOGY OF WOOD HARVESTING WITH THE HELP OF IMI-TATION MODELING ON PETRI NET

2018 ◽  
Vol 8 (1) ◽  
pp. 115-123
Author(s):  
Антон Соколов ◽  
Anton Sokolov ◽  
Евгений Осипов ◽  
Evgeniy Osipov

The article is devoted to the description of the solution of the problem of substantiating the technology of wood harvesting, using simulation modeling of production processes on Petri nets. The possibility of using specially developed simulation models for the operation of forestry machine complexes consisting of a harvester and forwarder is con-sidered, not only for making decisions on the choice of machines for the formation of complexes, but also for justifying technological solutions. The solution of the problem is described in the example of a plot of irregular shape with a long trail of considerable length. The basis of the used approach is the use of the method of discrete-event simulation on Petri nets. The results of field research, modeling and improvement of the technological process are given. The results of the simulation has showed that the forwarder is loaded unevenly under the conditions of the considered cutting area . The simple of this machine was 24.5 hours or 7% of the time. A down-time of harvester was 9 hours or 3%. As a result of analyzing the simulation of the machine downtime distribution over time, it was found that this was due to the constantly decreasing forwarder performance, due to the increasing distance of skidding. As a result of the carried out research, it has been recommended to make a change in the technology for the development of the cutting area, consisting in the fact that the harvester does not start with the apiaries which are close to the loading platform, but from distant ones at the end of the main line. Modeling performed after the introduction of changes into the model has showed that in case of a shift to the proposed technology for cutting logging, productivity of harvester + forwarder machine complex can be increased by 2.3% by reducing the total downtime of the machines. It is possible to recommend the use of such technology in case of logging sites with a long haul of considerable length. Thus, when solving the real production problem, the effectiveness of the proposed approach to the evaluation of options for technological solutions for logging

Author(s):  
Jeffrey W. Hermann ◽  
Edward Lin ◽  
Guruprasad Pundoor

Simulation is a very useful tool for predicting supply chain performance. Because there are no standard simulation elements that represent accurately the activities in a supply chain, there exist a variety of approaches for developing supply chain simulation models. To improve this situation, this paper describes a novel supply chain simulation framework that follows the Supply Chain Operations Reference (SCOR) model. This framework has been used for building powerful simulation models that integrate discrete event simulation and spreadsheets. The simulation models are hierarchical and use submodels that capture activities specific to supply chains. The SCOR framework provides a basis for defining the level of detail in a way as to include as many features as possible, while not making them industry specific. This approach enables the reuse of submodels, which reduces development time. The paper describes the implementation of the simulation models and how the submodels interact during execution.


SIMULATION ◽  
2021 ◽  
pp. 003754972110309
Author(s):  
Mohd Shoaib ◽  
Varun Ramamohan

We present discrete-event simulation models of the operations of primary health centers (PHCs) in the Indian context. Our PHC simulation models incorporate four types of patients seeking medical care: outpatients, inpatients, childbirth cases, and patients seeking antenatal care. A generic modeling approach was adopted to develop simulation models of PHC operations. This involved developing an archetype PHC simulation, which was then adapted to represent two other PHC configurations, differing in numbers of resources and types of services provided, encountered during PHC visits. A model representing a benchmark configuration conforming to government-mandated operational guidelines, with demand estimated from disease burden data and service times closer to international estimates (higher than observed), was also developed. Simulation outcomes for the three observed configurations indicate negligible patient waiting times and low resource utilization values at observed patient demand estimates. However, simulation outcomes for the benchmark configuration indicated significantly higher resource utilization. Simulation experiments to evaluate the effect of potential changes in operational patterns on reducing the utilization of stressed resources for the benchmark case were performed. Our analysis also motivated the development of simple analytical approximations of the average utilization of a server in a queueing system with characteristics similar to the PHC doctor/patient system. Our study represents the first step in an ongoing effort to establish the computational infrastructure required to analyze public health operations in India and can provide researchers in other settings with hierarchical health systems, a template for the development of simulation models of their primary healthcare facilities.


2015 ◽  
Vol 26 (5) ◽  
pp. 632-659 ◽  
Author(s):  
Abdullah A Alabdulkarim ◽  
Peter Ball ◽  
Ashutosh Tiwari

Purpose – Asset management has recently gained significance due to emerging business models such as Product Service Systems where the sale of asset use, rather than the sale of the asset itself, is applied. This leaves the responsibility of the maintenance tasks to fall on the shoulders of the manufacturer/supplier to provide high asset availability. The use of asset monitoring assists in providing high availability but the level of monitoring and maintenance needs to be assessed for cost effectiveness. There is a lack of available tools and understanding of their value in assessing monitoring levels. The paper aims to discuss these issues. Design/methodology/approach – This research aims to develop a dynamic modelling approach using Discrete Event Simulation (DES) to assess such maintenance systems in order to provide a better understanding of the behaviour of complex maintenance operations. Interviews were conducted and literature was analysed to gather modelling requirements. Generic models were created, followed by simulation models, to examine how maintenance operation systems behave regarding different levels of asset monitoring. Findings – This research indicates that DES discerns varying levels of complexity of maintenance operations but that more sophisticated asset monitoring levels will not necessarily result in a higher asset performance. The paper shows that it is possible to assess the impact of monitoring levels as well as make other changes to system operation that may be more or less effective. Practical implications – The proposed tool supports the maintenance operations decision makers to select the appropriate asset monitoring level that suits their operational needs. Originality/value – A novel DES approach was developed to assess asset monitoring levels for maintenance operations. In applying this quantitative approach, it was demonstrated that higher asset monitoring levels do not necessarily result in higher asset availability. The work provides a means of evaluating the constraints in the system that an asset is part of rather than focusing on the asset in isolation.


2012 ◽  
Vol 32 (3) ◽  
pp. 543-560 ◽  
Author(s):  
Alexandre Ferreira de Pinho ◽  
José Arnaldo Barra Montevechi ◽  
Fernando Augusto Silva Marins ◽  
Rafael Florêncio da Silva Costa ◽  
Rafael de Carvalho Miranda ◽  
...  

2020 ◽  
Vol 170 ◽  
pp. 03001 ◽  
Author(s):  
A. Hamroun ◽  
K. Labadi ◽  
M. Lazri

Car sharing systems emerged as a new answer to mobility challenges in smart and sustainable cities. Despite their apparent success, design and exploitation of such systems raise crucial strategic and operational challenges. To help planners and decision makers, simulation, analysis and optimization models are unavoidable. Based on the formal modelling and analysis power of stochastic Petri nets, this paper proposes a discrete event simulation model for electric car sharing systems for performance and analysis purposes, taking into account their complex dynamic behaviour, organization and parameters including capacities of the stations, battery and energy availability, locations of charging stations and also their car maintenance activities, not negligible compared to the case of bike-sharing systems.


Author(s):  
Ming Dong ◽  
Jianzhong Cha ◽  
Mingcheng E

Abstract In this paper, we realize knowledge-based discrete event simulation model’s representation, reasoning and implementation by means of object-oriented(OO) frame language. Firstly, a classes library of simulation models is built by using the OO frame language. And then, behaviours of simulation models can be generated by inference engines reasoning about knowledge base. Lastly, activity cycle diagrams can be used to construct simulation network logic models by connecting the components classes of simulation models. This kind of knowledge-based simulation models can effectively solve the modeling problems of complex and ill-structure systems.


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