scholarly journals Simulation Models for Offshore Port Service Concepts

2019 ◽  
Vol 9 (3) ◽  
pp. 584 ◽  
Author(s):  
Woo-sung Kim ◽  
Jonghoe Kim
Keyword(s):  
Simulation Model ◽  
Capacity Planning ◽  
Simulation Models ◽  
Search Space ◽  
Service Level ◽  
Operating Characteristics ◽  
Performance Metric ◽  
Mobile Harbor ◽  
Port System ◽  
Large Container

Offshore port service concepts were developed to flexibly respond to the emergence of large container ships and the increase in port trade volume. As one such offshore service concept, a mobile harbor system has recently been proposed. Although it is possible to effectively increase the capacity of existing ports through these mobile harbor systems, the methodology for evaluating the performance of a traditional port is limited when applied to evaluating the performance of the mobile harbor system. In this study, we develop a simulation model to analyze the mobile harbor system. The simulation model reflects the operating characteristics of the mobile harbor, and the performance metric of the system can be derived from the model. The results can be applied to capacity planning of a port system with a method that reduces search space. We applied our method to the Surabaya port in Indonesia to derive the optimal mobile harbor design that satisfies the required service level.

Simulation Models in Forest Management and Harvesting

1968 ◽  
Vol 44 (1) ◽  
pp. 7-13 ◽  
Author(s):  
R. M. Newnham
Keyword(s):  
Forest Management ◽  
Simulation Model ◽  
Stand Structure ◽  
Simulation Models ◽  
Stand Development ◽  
Operating Characteristics ◽  
Individual Tree ◽  
Harvesting Time ◽  
Advantages And Disadvantages

The advantages and disadvantages of simulation models are described and examples are given of their use in forestry. Stand models and a simulation model for pulpwood harvesting machines are described in some detail. Stand models simulate the growth of a stand on an individual tree basis and can be used for testing the effect of different silvicultural operations on subsequent stand development. The harvesting simulation models imitate the passage of a harvesting machine through a stand of pulpwood. They can be used to test the effect on harvesting time of using machines of different sizes and operating characteristics. The effect of stand structure on harvesting time can also be tested.

scholarly journals Guidelines to Calibrate a Multi-Residential Building Simulation Model Addressing Overheating Evaluation and Residents’ Influence

Buildings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 242
Author(s):  
Christoph Schünemann ◽  
David Schiela ◽  
Regine Ortlepp
Keyword(s):  
Simulation Model ◽  
Time Window ◽  
Residential Building ◽  
Simulation Models ◽  
Building Simulation ◽  
Night Time ◽  
Building Performance Simulation ◽  
Starting Point ◽  
3D Simulation Model ◽  
Building Physics

Can building performance simulation reproduce measured summertime indoor conditions of a multi-residential building in good conformity? This question is answered by calibrating simulated to monitored room temperatures of several rooms of a multi-residential building for an entire summer in two process steps. First, we did a calibration for several days without the residents being present to validate the building physics of the 3D simulation model. Second, the simulations were calibrated for the entire summer period, including the residents’ impact on evolving room temperature and overheating. As a result, a high degree of conformity between simulation and measurement could be achieved for all monitored rooms. The credibility of our results was secured by a detailed sensitivity analysis under varying meteorological conditions, shading situations, and window ventilation or room use in the simulation model. For top floor dwellings, a high overheating intensity was evoked by a combination of insufficient use of night-time window ventilation and non-heat-adapted residential behavior in combination with high solar gains and low heat storage capacities. Finally, the overall findings were merged into a process guideline to describe how a step-by-step calibration of residential building simulation models can be done. This guideline is intended to be a starting point for future discussions about the validity of the simplified boundary conditions which are often used in present-day standard overheating assessment.

Settings, Experimentation and Evaluation of the Simulation Models

2013 ◽  
Vol 309 ◽  
pp. 366-371 ◽  
Author(s):  
František Manlig ◽  
Radek Havlik ◽  
Alena Gottwaldova
Keyword(s):  
Simulation Model ◽  
New Technology ◽  
Simulation Models ◽  
Manufacturing Processes ◽  
Customer Requirements ◽  
Evaluation Functions ◽  
Operational Management ◽  
Minimum Number ◽  
User Friendly ◽  
Setting Parameters

This paper deals with research in computer simulation of manufacturing processes. The paper summarizes the procedures associated with developing the model, experimenting with and evaluating the model results. The key area is of experimentation with the simulation model and evaluation using indicators or multi-criteria functions. With regards to the experiment the crucial variables are the simulation model. The key ideas are to set the number of variables, depending on what a given simulation will be. For example, when introducing new technology into production, modify the type of warehouse, saving workers, thus economizing. The simulation models for the operational management uses simplified models, if possible, a minimum number of variables to obtain the result in shortest possible time. These models are more user friendly and the course will be conducted mostly in the background. An example of a criteria function is the number of parts produced or production time. Multi-criteria function has given us the opportunity to make better quality decisions. It is based on the composition of several parameters, including their weight to one end point. The type of evaluation functions, whether it is an indicator or criteria function is selected and based on customer requirements. In most cases it is recommended to use the multi-dimensional function. It gives us a more comprehensive view of the results from the model and facilitates decision-making. The result of this paper is a display of setting parameters for the experimentation on a sample model. Furthermore, the comparisons of results with a multi-criteria objective function and one-criterion indicator.

A Method to Define the Best Weld Sequence Using a Limited Number of Welding Simulation Analysis

2015 ◽  
Author(s):  
Mahyar Asadi ◽  
Ghazi Alsoruji
Keyword(s):  
Simulation Model ◽  
Surrogate Model ◽  
Simulation Analysis ◽  
Combinatorial Problem ◽  
Fem Analysis ◽  
Simulation Models ◽  
Computational Time ◽  
Optimal Sequence ◽  
Welded Structure ◽  
Welding Sequence

Weld sequence optimization, which is determining the best (and worst) welding sequence for welding work pieces, is a very common problem in welding design. The solution for such a combinatorial problem is limited by available resources. Although there are fast simulation models that support sequencing design, still it takes long because of many possible combinations, e.g. millions in a welded structure involving 10 passes. It is not feasible to choose the optimal sequence by evaluating all possible combinations, therefore this paper employs surrogate modeling that partially explores the design space and constructs an approximation model from some combinations of solutions of the expensive simulation model to mimic the behavior of the simulation model as closely as possible but at a much lower computational time and cost. This surrogate model, then, could be used to approximate the behavior of the other combinations and to find the best (and worst) sequence in terms of distortion. The technique is developed and tested on a simple panel structure with 4 weld passes, but essentially can be generalized to many weld passes. A comparison between the results of the surrogate model and the full transient FEM analysis all possible combinations shows the accuracy of the algorithm/model.

Rotorcraft Lateral-Directional Oscillations: The Anatomy of a Nuisance Mode

2021 ◽  
Author(s):  
Dheeraj Agarwal ◽  
Linghai Lu ◽  
Gareth D. Padfield ◽  
Mark D. White ◽  
Neil Cameron
Keyword(s):  
Simulation Model ◽  
Simulation Models ◽  
Flight Test ◽  
Flight Simulation ◽  
Stability And Control ◽  
Systems Research ◽  
Control Derivatives ◽  
Research Aircraft ◽  
Level Of Understanding ◽  
And Control

High-fidelity rotorcraft flight simulation relies on the availability of a quality flight model that further demands a good level of understanding of the complexities arising from aerodynamic couplings and interference effects. One such example is the difficulty in the prediction of the characteristics of the rotorcraft lateral-directional oscillation (LDO) mode in simulation. Achieving an acceptable level of the damping of this mode is a design challenge requiring simulation models with sufficient fidelity that reveal sources of destabilizing effects. This paper is focused on using System Identification to highlight such fidelity issues using Liverpool's FLIGHTLAB Bell 412 simulation model and in-flight LDO measurements from the bare airframe National Research Council's (Canada) Advanced Systems Research Aircraft. The simulation model was renovated to improve the fidelity of the model. The results show a close match between the identified models and flight test for the LDO mode frequency and damping. Comparison of identified stability and control derivatives with those predicted by the simulation model highlight areas of good and poor fidelity.

Research on Matching Characteristics of Ship-Engine-Propeller of COGAG

2021 ◽  
Author(s):  
Zhitao Wang ◽  
Jiayi Ma ◽  
Haichao Yu ◽  
Tielei Li
Keyword(s):  
Steady State ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Research Work ◽  
Simulation Models ◽  
Operating Characteristics ◽  
Modular Modeling ◽  
Steady State Operation ◽  
Pitch Ratio ◽  
Main Engine

Abstract The combined gas turbine and gas turbine power propulsion device (COGAG power propulsion device) is an advanced combined power system, which uses multiple gas turbines as the main engine to drive propellers to propel the ship. COGAG power propulsion device has high power density, excellent stability and maneuverability, it receives more and more attention in the field of ship power at home and abroad. This article takes the COGAG power propulsion device as the research object, uses simulation methods to study its steady-state operating characteristics, and conducts a ship-engine-propeller optimization matching analysis based on economy and maneuverability. The research work carried out in this article is as follows. Firstly, according to the structural relationship between the various components and the system thermal cycle mode of the COGAG power propulsion device, establish the controller, main engine, gear box, clutch, shafting, propeller, ship and other components and simulation models of the system with the modular modeling idea. Secondly, divide the gears according to ship speed. For the four working modes of single-gas turbine with load, dual-gas turbine with load, three-gas turbine with load, and four-gas turbine with load, analysis the ship-engine-propeller optimization matching of the COGAG power propulsion device based on economy and maneuverability, and calculate the best shaft speed and propeller pitch ratio in each gear, so as to obtain the steady-state operation characteristics of the COGAG power propulsion device based on the ship-engine-propeller matching, which provides a basis for determining the target parameters of the dynamic process.

scholarly journals AVAILABILITY ASSESSMENT SIMULATIONS FOR ALLOCATING HUMAN RESOURCES IN AIRSPACE CONTROL CENTERS

2013 ◽  
Vol 4 (1) ◽  
pp. 61-76
Author(s):  
Walter Nogueira Pizzo
Keyword(s):  
Human Resources ◽  
Simulation Model ◽  
Control Systems ◽  
Computer Systems ◽  
Service Level ◽  
Point Of View ◽  
Operations And Maintenance ◽  
Human Operators ◽  
Availability Assessment

Airspace control systems introduced automation into functions previously performed by human operators. This situation increased the dependence on the availability of computer systems, in which degraded operation events can reduce the service level at any controlled airspace. This paper presents a relationship between availability and allocation of human resources in these centers, where maintenance and operations personnel are occasionally asked to repair losses caused by automated functions. A simulation model for the Arena tool is presented, to access availability, and then the operational point of view is explored, focusing on the required availability scenarios. The results presented herein can help determine the size of operations and maintenance teams, considering the reliability and maintainability parameters of airspace control systems.

scholarly journals Modeling and analysis of the characteristics of SiC MOSFET

2021 ◽  
Vol 2125 (1) ◽  
pp. 012051
Author(s):  
Guoqing Qiu ◽  
Kedi Jiang ◽  
Shengyou Xu ◽  
Xin Yang ◽  
Wei Wang
Keyword(s):  
Simulation Model ◽  
Circuit Simulation ◽  
Power Conversion ◽  
Simulation Models ◽  
Data Sheet ◽  
Superior Performance ◽  
Power Devices ◽  
Matlab Simulink ◽  
Modeling And Analysis ◽  
Mathematical Processing

Abstract Although the superior performance of SiC MOSFET devices has beenvalidated by many studies, it is necessary to overcome many technical bottlenecks to make SiC MOSFET gradually replace Si-based power devices into the mainstream. In view of the current situation where the performance of SiC MOSFETs in power conversion devices cannot be evaluated well at this stage, it is necessary to carry out fine modeling of SiC MOSFETs and establish accurate simulation models. In this paper, the powerful mathematical processing capability and rich modules of Matlab/Simulink are used to build a SiC MOSFET model, and then the product data sheet is compared with the fitted data. The results show that the switching simulation waveforms are in general agreement with the data sheet waveforms, and the error is less than 7%. Verifing the accuracy of the model and reducing the difficulty of modeling, it provides a new idea for establishing the circuit simulation model of SiC MOSFET in Matlab/Simulink.

scholarly journals Model Driven Combat Effectiveness Simulation Systems Engineering

2020 ◽  
Vol 70 (1) ◽  
pp. 54-59
Author(s):  
Zhi Zhu ◽  
Yonglin Lei ◽  
Yifan Zhu
Keyword(s):  
Decision Making ◽  
Simulation Model ◽  
Conceptual Model ◽  
Systems Engineering ◽  
Simulation Models ◽  
Proof Of Concept ◽  
Model Driven Engineering ◽  
Model Driven ◽  
Combat Effectiveness ◽  
Simulation Systems

Model-driven engineering has become popular in the combat effectiveness simulation systems engineering during these last years. It allows to systematically develop a simulation model in a composable way. However, implementing a conceptual model is really a complex and costly job if this is not guided under a well-established framework. Hence this study attempts to explore methodologies for engineering the development of simulation models. For this purpose, we define an ontological metamodelling framework. This framework starts with ontology-aware system conceptual descriptions, and then refines and transforms them toward system models until they reach final executable implementations. As a proof of concept, we identify a set of ontology-aware modelling frameworks in combat systems specification, then an underwater targets search scenario is presented as a motivating example for running simulations and results can be used as a reference for decision-making behaviors.

Exploring incomplete information in maintenance materials inventory optimization

2014 ◽  
Vol 114 (1) ◽  
pp. 144-158 ◽  
Author(s):  
Antti Puurunen ◽  
Jukka Majava ◽  
Pekka Kess
Keyword(s):  
Sensitivity Analysis ◽  
Simulation Model ◽  
Input Data ◽  
Real Life ◽  
Significant Risk ◽  
Service Level ◽  
Content Type ◽  
Imperfect Data ◽  
Inventory Optimization ◽  
Critical Materials

Purpose – Ensuring the sufficient service level is essential for critical materials in industrial maintenance. This study aims to evaluate the use of statistically imperfect data in a stochastic simulation-based inventory optimization where items' failure characteristics are derived from historical consumption data, which represents a real-life situation in the implementation of such an optimization model. Design/methodology/approach – The risks of undesired shortages were evaluated through a service-level sensitivity analysis. The service levels were simulated within the error of margin of the key input variables by using StockOptim optimization software and real data from a Finnish steel mill. A random sample of 100 inventory items was selected. Findings – Service-level sensitivity is item specific, but, for many items, statistical imprecision in the input data causes significant uncertainty in the service level. On the other hand, some items seem to be more resistant to variations in the input data than others. Research limitations/implications – The case approach, with one simulation model, limits the generalization of the results. The possibility that the simulation model is not totally realistic exists, due to the model's normality assumptions. Practical implications – Margin of error in input data estimation causes a significant risk of not achieving the required service level. It is proposed that managers work to improve the preciseness of the data, while the sensitivity analysis against statistical uncertainty, and a correction mechanism if necessary, should be integrated into optimization models. Originality/value – The output limitations in the optimization, i.e. service level, are typically stated precisely, but the capabilities of the input data have not been addressed adequately. This study provides valuable insights into ensuring the availability of critical materials.

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