Predicting construction productivity using situation-based simulation models

2006 ◽  
Vol 33 (12) ◽  
pp. 1585-1600 ◽  
Author(s):  
Eldon Choy ◽  
Janaka Y Ruwanpura
Keyword(s):  
Simulation Modeling ◽  
Simulation Models ◽  
Construction Site ◽  
Construction Operations ◽  
Construction Productivity ◽  
Modeling Simulation ◽  
Data Source ◽  
Simulation Results ◽  
Problematic Situations ◽  
The Impact

Construction site operations are very complex, and they involve complicated relationships among numerous tasks, factors, obstacles, risks, and uncertainties, or triggering situations that affect productivity. To improve the performance of construction operations, one needs to understand the impact these triggering situations have on productivity. The paper discusses a recently developed technique, called situation-based simulation modeling, that is used to model the triggering situations in construction to predict productivity. This tool can model the cause-and-effect relationships among various triggering situations, which previous construction models have ignored. Construction operations that were directly observed and recorded for more than 3500 person-hours served as the data source for the development of the model. The simulation results are not only able to accurately predict productivity relative to the actual productivity observed at the site, but also provide the basis for recommendations to mitigate problematic situations to improve productivity.Key words: construction, productivity, modeling, simulation, situation-modeling.

Influence of Oriented Perforation Design on Refracture Reorientation: Simulation and Experiment

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Minhui Qi ◽  
Mingzhong Li ◽  
Tiankui Guo ◽  
Chunting Liu ◽  
Song Gao ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Large Scale ◽  
Simulation Models ◽  
Fracture Initiation ◽  
Simulation Method ◽  
Induced Stress ◽  
Study Results ◽  
Simulation Results ◽  
Fracturing Experiments ◽  
The Impact

The oriented perforating is the essential technique to guide the refracture reorientation, but the influence of the oriented perforation design on the refracture steering radius is still unclear. In this paper, the factors influencing the refracture reorientation were studied by simulation models and experiments. The effects of initial fracture, well production, and perforations on the refracture initiation and propagation were analyzed. Three-dimensional finite element models were conducted to quantify the impact of perforation depth, density, and azimuth on the refracture. The large-scale three-axis hydraulic fracturing experiments guided by oriented perforations were also carried out to verify the fracture initiation position and propagation pattern of the simulation results. The research results showed that perforations change the near-wellbore induced stress distribution, thus changing the steering radius of the refracture. According to the simulation results, the oriented perforation design has a significant influence on the perforation guidance effect and refracture characteristics. Five hydraulic fracturing experiments proved the influence of perforating parameters on fracture initiation and morphology, which have a right consistency between the simulation results. This paper presents a numerical simulation method for evaluating the influence of the refracture reorientation characteristics under the consideration of multiple prerefracturing induced-stress and put forward the oriented perforation field design suggestions according to the study results.

scholarly journals Data-Driven Simulation for Evaluating the Impact of Lower Arrival Aircraft Separation on Available Airspace and Runway Capacity at Tokyo International Airport

Aerospace ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 165
Author(s):  
Katsuhiro Sekine ◽  
Furuto Kato ◽  
Kota Kageyama ◽  
Eri Itoh
Keyword(s):  
Simulation Models ◽  
Weather Conditions ◽  
Air Traffic ◽  
Data Driven ◽  
Wake Turbulence ◽  
Automation Systems ◽  
Delay Times ◽  
Simulation Results ◽  
The Impact ◽  
Terminal Area

Although the application of new wake turbulence categories, the so-called “RECAT (wake turbulence category re-categorization)”, will realize lower aircraft separation minima and directly increase runway throughput, the impacts of increasing arrival traffic on the surrounding airspace and arrival traffic flow as a whole have not yet been discussed. This paper proposes a data-driven simulation approach and evaluates the effectiveness of the lower aircraft separation in the arrival traffic at the target airport. The maximum runway capacity was clarified using statistics on aircraft types, stochastic distributions of inter-aircraft time and runway occupancy time, and the levels of the automation systems that supported air traffic controllers’ separation work. Based on the estimated available runway capacity, simulation models were proposed by analyzing actual radar track and flight plan data during the 6 months between September 2019 and February 2020, under actual operational constraints and weather conditions. The simulation results showed that the application of RECAT would reduce vectoring time in the terminal area by 7% to 10% under the current airspace and runway capacity when following a first-come first-served arrival sequence. In addition, increasing airspace capacity by 10% in the terminal area could dramatically reduce en-route and takeoff delay times while keeping vectoring time the same as under the current operation in the terminal area. These findings clarified that applying RECAT would contribute to mitigating air traffic congestion close to the airport, and to reducing delay times in arrival traffic as a whole while increasing runway throughput. The simulation results demonstrated the relevance of the theoretical results given by queue-based approaches in the authors’ past studies.

Studying the Impact of Return Current Path on the EM Simulation of High-speed Package Designs

2011 ◽  
Vol 2011 (1) ◽  
pp. 000061-000068
Author(s):  
Darryl Kostka ◽  
Antonio Ciccomancini Scogna
Keyword(s):  
High Speed ◽  
Ground Plane ◽  
Three Dimensional ◽  
Simulation Models ◽  
Current Path ◽  
Cavity Resonances ◽  
Simulation Results ◽  
The Impact ◽  
Simulation Time

Three-dimensional electromagnetic simulation models are often simplified in order to reduce the simulation time and memory requirements without sacrificing the accuracy of the results. A commonly adopted methodology in the simulation of electronic package designs is to truncate the size of the package model leaving only a few important features surrounding the nets of interest. In this paper we demonstrate that this simplification can have a significant impact of the simulation results if it is not performed carefully and it can introduce spurious/non physical resonances. The interaction between cavities and signals is first studied using a simple coupled differential via test structure. It is demonstrated that the return currents generated by these vias excite cavity resonances in power-ground plane pairs causing them to behave as parallel-plate waveguides. The role of interplane shorting vias in suppressing cavity resonances is then investigated and the impact of boundary conditions on the simulation results of package models is also shown and discussed. Finally, a realistic complex multilayer package model is analyzed and it is demonstrate that through proper truncation of the geometry, accurate results can be obtained.

Optimization Design and Simulation Research of Hydraulic Test Bench

2013 ◽  
Vol 744 ◽  
pp. 23-26
Author(s):  
Fan He Meng ◽  
Jun Hua Zhang
Keyword(s):  
Experimental Data ◽  
Simulation Modeling ◽  
Optimization Design ◽  
Test Bench ◽  
Simulation Models ◽  
Hydraulic Test ◽  
Simulation Research ◽  
Simulation Results ◽  
Amesim Simulation ◽  
Hydraulic Circuits

For the limitations of the existing hydraulic test bench for experimenting with multi-species of hydraulic components, the additional cartridge valve circuit and multi-way directional valve circuit were designed. The AMESim simulation models of the hydraulic test benchs basic hydraulic circuits were established and simulated. Then the simulation results were compared with the experimental data to get some principles of simulation modeling and optimize the models. These principles were used to simulate the additional hydraulic circuits. Through analysis of the simulation results, theory supports were provided to the optimal design of hydraulic test bench. In this way, the existing hydraulic test bench can be fully used and the suitable components were selected, reducing the waste of resources. Besides, the simulation models can be used as part of the virtual hydraulic teaching.

Mechanism Study on the Impact of Low Pressure Accumulator with Mechanical Mechanics to Hydraulic Impactor

2014 ◽  
Vol 908 ◽  
pp. 296-300
Author(s):  
Zhong Yi Cao ◽  
Xiang Yang Huang ◽  
Wan Rong Wu
Keyword(s):  
Model Calculation ◽  
Impact Energy ◽  
Simulation Models ◽  
Mathematic Model ◽  
Low Pressure ◽  
Small Degree ◽  
Simulation System ◽  
Mechanism Study ◽  
Simulation Results ◽  
The Impact

To investigate the impact of low pressure accumulator to the performance of hydraulic impactor, mathematic model of hydraulic impactor was established. By application of AMESim, The simulation models of hydraulic impactor with low pressure accumulator and hydraulic impactor without low pressure accumulator were obtained. After model calculation, the displacement, velocity of the piston and the return pressure were shown in figures. Rationality of the simulation system was verified by the compare between simulation results and experimental results. The simulation results show that low pressure accumulator can increase the impact energy and frequency of hydraulic impactor in a small degree and reduce the impact of return pressure significantly. Article provides theory basis for the designation of hydraulic impactor.

Computational Modeling of Extreme Heat Flux Microcooler for GaN-Based HEMT

2015 ◽  
Author(s):  
Hyoungsoon Lee ◽  
Yoonjin Won ◽  
Farzad Houshmand ◽  
Catherine Gorle ◽  
Mehdi Asheghi ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Single Phase ◽  
Simulation Models ◽  
Transfer Coefficients ◽  
Two Phase ◽  
Ansys Fluent ◽  
Heat Transfer Coefficients ◽  
Gan Hemt ◽  
Simulation Results ◽  
The Impact

This study explores an extreme heat flux limit of microcooler for GaN-based HEMTs (high electron mobile transistors) which have local power densities exceeding 30 kW/cm2 using both solid conduction simulation and single-phase/two-phase conjugate simulations. Solid conduction simulation models are developed for full geometry of the microcooler to account for the overall thermal resistances from GaN HEMT to working fluid. This allows investigating the temperature distribution of the suggested microcooler. Parametric studies are also performed to investigate the impact of geometries and heat transfer coefficients on the junction temperature. The solid conduction simulation results using COMSOL Multiphysics agree well with single-cell ANSYS Fluent simulation results. Separately, fluid-solid conjugate CFD (Computational Fluid Dynamics) simulation models provide the detailed flow information in the microchannel using a single-channel geometry with symmetry boundary conditions. Single-phase CFD simulations obtain the lower bound of total pressure drop and heat transfer coefficient at the microchannel walls for a mass velocity range of G = 6000–24000 kg/m2-s. The local temperatures and velocity distributions are reported that can help with identifying the locations of the maximum velocity and recirculation regions that are susceptible to dryouts. Two additional alternative tapered inlet designs are proposed to alleviate the significant pressure loss at the entrance of the SiC channel. The impact of the tapered inlet designs on pressure drops and heat transfer coefficients is also investigated. Two-phase simulations in microchannel are conducted using Volume-of-Fluid (VOF) method embedded in ANSYS Fluent to investigate two-phase flow patterns, flow boiling, and temperature distributions within the GaN HEMT device and SiC etched mircochannels. A user-defined function (UDF) accounts for the phase change process due to boiling at the microchannel walls. The results show that the time relaxation factor, ri has a strongly influence on both numerical convergence and flow solutions.

Studying the Impact of Return Current Path on the EM Simulation of High-Speed Package and Board Designs

2012 ◽  
Vol 9 (2) ◽  
pp. 52-64
Author(s):  
Darryl Kostka ◽  
Antonio Ciccomancini Scogna
Keyword(s):  
High Speed ◽  
Ground Plane ◽  
Three Dimensional ◽  
Simulation Models ◽  
Combined Model ◽  
Current Path ◽  
Cavity Resonances ◽  
Simulation Results ◽  
The Impact

Three-dimensional electromagnetic simulation models are often simplified in order to reduce simulation time and memory requirements without sacrificing the accuracy of the results. A commonly adopted methodology in the simulation of complex electronic package and board designs is to truncate the size of the model, leaving only a few important features surrounding the nets of interest. In this paper we demonstrate that this simplification can have a significant impact on the simulation results if it is not performed carefully, and it can introduce spurious nonphysical resonances. The interaction between cavities and signals is first studied using a simple coupled differential via test structure. It is demonstrated that the return currents generated by these vias excite cavity resonances in power-ground plane pairs causing them to behave as parallel-plate waveguides. The role of interplane shorting vias in suppressing cavity resonances is then investigated and the impact of boundary conditions on the simulation results of package models is also shown and discussed. The focus is then shifted to PCB/package cosimulation and the impact of different truncation schemes is discussed through the simulation of test structures of varying complexity. A simulation methodology is then proposed and is verified for a combined model of a realistic complex multilayer package and board and it is demonstrated that accurate results can be obtained through proper truncation of the geometry.

Process simulation modeling of phytophagans' influence on the yield of seed fruit crops

2019 ◽  
pp. 138-143
Author(s):  
V. A. Shishkin ◽  
E. P. Rybalkin ◽  
E. B. Balykina
Keyword(s):  
Process Simulation ◽  
Simulation Modeling ◽  
Software Package ◽  
Development Process ◽  
Simulation Models ◽  
Vegetation Period ◽  
Fruit Crops ◽  
Generational Change ◽  
Apple Trees ◽  
Nonlinear Characteristics

Simulation modeling of phytophagans’ influence on the yield of seed fruit crops, in particular apple trees, was carried out. By means of simulation models the importance of phytophagans’ influence at different stages of the vegetation period and the period of fruit ripening was revealed. The software package Matlab was used to build simulation models. As a result, simulation models with nonlinear characteristics were obtained, which maximally reflected the studied processes. The developed models imitate the process of phytophagans’ development. Generation change of pests and all stages of their development are simulated. Their respective numbers are recorded at each stage for all generations. The development process at each stage is modeled by separate subsystems of the simulation model. To simulate the development of one generation of pests, these subsystems are connected by external links. In addition, part of the relationships provides a simulation of generational change. There are a number of input parameters that allow to configure the simulation of the process of changing generations, taking into account the peculiarities of the development of various phytophagans.

Infoveillance based on Social Sensors to Analyze the impact of Covid19 in South American Population (Preprint)

2020 ◽  
Author(s):  
Josimar E. Chire Saire
Keyword(s):  
Text Mining ◽  
Electronic Communication ◽  
Spanish Speakers ◽  
South American ◽  
South American Population ◽  
The People ◽  
Data Source ◽  
The Impact ◽  
General Concern ◽  
Social Sensors

BACKGROUND Infoveillance is an application from Infodemiology field with the aim to monitor public health and create public policies. Social sensor is the people providing thought, ideas through electronic communication channels(i.e. Internet). The actual scenario is related to tackle the covid19 impact over the world, many countries have the infrastructure, scientists to help the growth and countries took actions to decrease the impact. South American countries have a different context about Economy, Health and Research, so Infoveillance can be a useful tool to monitor and improve the decisions and be more strategical. The motivation of this work is analyze the capital of Spanish Speakers Countries in South America using a Text Mining Approach with Twitter as data source. The preliminary results helps to understand what happens two weeks ago and opens the analysis from different perspectives i.e. Economics, Social. OBJECTIVE Analyze the behaviour of South American Capitals in front of covid19 pandemics and show the helpfulness of Text Mining Approach for Infoveillance tasks. METHODS Text Mining process RESULTS - Argentina and Venezuela capitals are the biggest number of post during this period, opposite with Bolivia, Ecuador and Uruguay. - Most relevant users are related to mass media like radio, television or newspapers. - There is a general concern about covid19 but every country talks about different areas: Economics, Health, Environmental Impact. CONCLUSIONS Infoveillance based on Social Sensors with data coming from Twitter can help to understand the trends on the population of the capitals. Besides, it is necessary to filter the posts for processing the text and get insights about frequency, top users, most important terms. This data is useful to analyse the population from different approaches. INTERNATIONAL REGISTERED REPORT RR2-https://doi.org/10.1101/2020.04.06.20055749

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