Creation Of Simulation Models Research Articles

4-D Modeling of a Sustainable Economy: Integrating Economic, Environmental, Population, and Monetary Models

Leontief’s Input-Output Analysis equation has long been used around the world and especially in China to calculate production and consumption balances. This research shows how to connect environmental and financial balances to production balances in an economic region by generalizing the Leontief’s equations from vector form to tensor form. This is important for creating economic and environmental policies aimed at sustainable economies. It provides a general modeling approach which can quantitatively connect economic processes with biological and physical processes of the environment. If economic processes cannot be measured as to their real physical/biological impacts, one does not know whether or not such economic processes are sustainable in nature. The tensor generalization also enables the depiction of both economic processes as production and finance. The use of tensor mathematics for input-output models of both economy and its environment provides a data architecture to create simulation models of the environmental impact of an economy.

Simulation Assisted Nanoscale Imaging of Single Live Cells with Scanning Electrochemical Microscopy

AbstractNanoelectrodes have become an area of significant interest in recent years, which provide a number of advantages for imaging with scanning electrochemical microscopy (SECM). Since the resolution of SECM imaging is directly dependent on the size of the electrode probe, the reduced surface area of nanoelectrodes allows for the imaging of smaller sample features, or more localized electrochemical reactivity. Nanoelectrodes with a radius of 130 nm are employed to image the surface of single live cells. The use of nanoscale imaging, however, introduces additional complexity into the simulation modeling of the cell surface geometry and electrochemical reactivity. The creation of tailored simulation models accounting for these specific physical conditions is utilized to overcome the additional challenges to the characterization of the electrochemical system. Methodologies for the experimental mapping and creation of 3D simulation models of single live cells have been well developed, which are presented herein. These developments include characterization of cell surface topography, tip‐to‐cell distance, as well as cell membrane permeability quantification. The advanced quantification of the complex nanoscale imaging of single live cells assisted by theoretical simulations provides increased versatility to SECM as an already powerful bioanalytical tool.

Simulation of Downlink of 10G-PON FTTH in the city of Košice

AbstractOptical fiber has the great advantages of capacity and reliability. That is why network providers started to deploy FTTx (Fiber-To-The-x) optical access using various PON (Passive Optical Network) architectures. The leading technology right now is Gigabit PON (GPON). However, with increasing amount of multimedia we need to further develop existing technologies to go on with these high demands. Fiber-To-The-Home (FTTH) using 10G-PON technology for broadband access application is effective solution for high speed networks with high capacity. In this paper, we look at the passive optical network in the city of Košice and based on the real network we created simulation model of downlink of 10G-PON based FTTH with triple-play service.

Calculation and Simulation Model of a System RopeCon

Transport of material plays a very important role in the mining. The main task of the material transport is conveying raw materials into the storage bin. There are applied in the area of bulk solid transportation not only the traditional kinds of transport. The unconventional transport systems are usually developed from the “classic” systems. One of the new transport methods is application of the system RopeCon, which represents a combination of the rope transport and belt transport. This paper deals with the creation of geometry and simulation model of the RopeCon conveyor.

Assessment of prehospital hemorrhage and airway care using a simulation model.

The quality of prehospital care impacts patient outcomes. Military efforts have focused on training revision and the creation of high-fidelity simulation models to address potentially survivable injuries. We sought to investigate the applicability of models emphasizing hemorrhage control and airway management to a civilian population. Prehospital health care providers (PHPs) undergoing their annual training were enrolled. A trauma scenario was simulated with two modules: hemorrhage control and airway management. Experienced raters used a validated tool to assess performance. Pearson correlation, logistic regression, and χ tests were used for analysis. Ninety-five PHPs participated with a mean experience of 15.9 ± 8.3 years, and 7.4% reported past military training. The PHPs' overall execution rate of the six hemorrhage control measures varied from 38.9% to 88.4%. The median blood loss was 1,700 mL (interquartile range, 1,043-2,000), and the mean global rater score was 25.0 ± 7.4 (scale, 5-40). There was a significant relationship between PHP profession and past military experience to their consideration of blood transfusion and tranexamic acid. An inverse relationship between blood loss and global rater score was found (r = -0.59, n = 88, p = 1.93 × 10). After simulated direct laryngoscope failure in the airway module, 58% of PHPs selected video laryngoscopy over placement of a supraglottic airway. Eighty-six percent of participants achieved bilateral chest rise in the manikin regardless of management method. Participants reported improved comfort with skills after simulation. Our data reveal marginal performance in hemorrhage control regardless of the PHP's prior experience. The majority of PHPs were able to secure an advanced airway if direct laryngoscope was unavailable with a predisposition for video laryngoscopy over supraglottic airway. Our findings support the need for continued training for PHPs highlighting hemorrhage control maneuvers and increased familiarity with airway management options. Improved participant confidence posttraining gives credence to simulation training. Prognostic/epidemiological study, level III.

SISTEM DINAMIS PENILAIAN KINERJA PRODUKSI TEH KEBUN BANTARAN PT PERKEBUNAN NUSANTARA XII

In the last ten years, the performance of Indonesia’s tea agroindustry has been decreased. It is shown by the decreasing of tea estate area as much as 2.18 percent per year, tea production decreased as much as 0.8 percent, and export volume decreased as much as 1,07 percent per year. This study were aimed to identify performance measurement results of tea production at Bantaran plantation area PT Perkebunan Nusantara XII based on the achievement of RKAP and evaluated the performance achieved through the production of tea agroindustry by dynamic system method. This method allowed to conduct comprehensive studies to study the behavior and improved system performance. This study was started from the observation, interviews, and document collection, which then was made causal loop diagram to the simulation model creation and validation of the model made. From the simulation, it came with conclusion, if there was no policy change, then Bantaran plantation area had a decreased performance status.
 Keywords: tea production, dynamic system, performance measurement

Performance analysis in emergency departments: a data-driven approach

PurposeThis paper aims to investigate the process performances in Emergency Departments (EDs) with a novel data-driven approach, permitting to discover the entire patient-flow, deploy the performances in term of time and resources on the activities and flows and identify process deviations and critical bottlenecks. Moreover, the use of this methodology in real time might dynamically provide a picture of the current situation inside the ED in term of waiting times, crowding, resources, etc., supporting the management of patient demand and resources in real time.Design/methodology/approachThe proposed methodology exploits the process-mining techniques. Starting from the event data inside the hospital information systems, it permits automatically to extract the patient-flows, to evaluate the process performances, to detect process exceptions and to identify the deviations between the expected and the actual results.FindingsThe application of the proposed method to a real ED revealed being valuable to discover the actual patient-flow, measure the performances of each activity with respect to the predefined targets and compare different operating situations.Practical implicationsStarting from the results provided by this system, hospital managers may explore the root causes of deviations, identify areas for improvements and hypothesize improvement actions. Finally, process-mining outputs may provide useful information for creating simulation models to test and compare alternative ED operational scenarios.Originality/valueThis study responds to the need of novel approaches for monitoring and evaluating processes performances in the EDs. The novelty of this data-driven approach is the opportunity to timely connect performances, patient-flows and activities.

USE OF SIMULATION MODELS FOR OPTIMIZATION OF THE CONTACT APPARATUS WORK IN THE SULFURIC ACID PRODUCTION

In the modern world, in connection with the rapid development of computer technology and software widely used A far of processes in chemical industry is continuous and a production lasts twenty-four-hour. The stop of such processes results in considerable economic losses. Realization of active experiment on a production is complicated (through the necessity of stop of productive process and risk of damage of industrial equipment a researcher). Realization of passive experiment often does not give to the researcher of sufficient information about the looked after object (through the very small rejections of entrance signals of object and impossibility of influence a researcher on every entrance signal separately). An attractive alternative in this case is creation of simulation model.The aim of the article is a publication of results of the use of simulation models for optimization of work of pin vehicle in the production of sulphuric acid.Creation of simulation model settles many problems. There is possibility to set any values of entrance signals independent of each other. There is possibility to design emergency situations. In the modern world, transients in chemical industry last during many hours. By means of computer simulation models information about a transient it is possible to get almost instantly (depending on the amount of calculations and power of the computing engineering).Of long duration continuous process the process of pin oxidization can exemplify in the production of sulphuric acid. Oxidization of sulphureous anhydride SO2 in sulfuric SO3 takes place in pin vehicles at the presence of vanadium catalyst. Into a vehicle there are four layers of pin mass. Pin mass is placed on grates. One of basic indexes of quality of work of pin vehicles there is a degree of contact xp, which is calculated on a formula.As evidently from the results of design, the identical values of middle temperatures (levels) are situated along direct. This surface can be used for development of the system of automatic control. Will set the problem to support such temperature condition at which a middle temperature would be in the second area (green area). Thus a management would be near to optimal and there would not be a risk of stop of reaction in case of sudden hit in the area of stop of reaction (white area).On the real object the system of automatic control supports the stationary temperatures of gas on an entrance to every layer of pin mass (catalyst). As a rule gas temperatures on entrances to every layer lie within the limits of 420-450 °C. A maximal temperature on an exit from the layer of catalyst folds close 600 °C. Decline of gas temperature to 400 °C and below given to the stop of reaction (and it is impermissible in a continuous production). Transients in a pin vehicle last a few hours. The new start of process stipulates the considerable losses of time (id est is a loss). Increase of temperature to 650 °C and higher results in the overheat of catalyst to his spoilage. In this case it is necessary to stop a process and replace a catalyst (and these are very considerable material charges). Realization of active experiment is simply impermissible clearly, that. A simulation model enables how pleasingly to influence on a temperature condition into a pin vehicle. There is possibility to investigate temperature conditions near to the emergency (at a temperature on an entrance to one of layers of catalyst close or to the temperature on an exit from one of layers of catalyst close 650 °C).For creation of simulation model it is necessary foremost to formalize an object. For the mathematical design of behavior of object (dynamics and statics) it comfortably to use the system of differential equalizations. Differential equalizations can be got analytically from material balances. It is also possible to get differential equalizations after treatment of results of passive or active experiment. On results the conducted imitation design it is possible to do next conclusions:1. An object is almost not sensible to short-term indignations. Id est there is not a necessity to design the system of automatic control with a high fast-acting. Recommended to steel of time for control system by a concentration and gas temperature approximately equal to 10 minutes.2. Most dangerous for the process of pin oxidization is an increase of concentration of SO2. A nominal concentration is 7,4 %. At the increase of concentration gas must be diluted by air (for normalization of concentration). At development of the system of automatic control it follows to take into account next limitations: maximal static rejection of concentration ± 0,1 %; maximal dynamic (short-term) rejection of concentration ± 1 %.3. Desirable (near to optimal) are tasks of temperature and concentrations within the limits of the second area. Dependence between an optimal temperature and concentration entrance.

An approach to business process simulation using mined probabilistic models

There are many approaches on how to analyse business processes, but the simulation is still not widely employed due to high costs associated with simulation model creation. In this paper, an approach on how to automatically generate dynamic business process simulation model is presented. The approach discovers belief network of the process from an event log and uses it to generate a simulation model automatically. Such model then can be further customised to facilitate analysis. For evaluation of the approach, conformance of the simulation results with the source event logs was calculated. The simulation results were event logs that were generated during the simulation of the discovered models. The evaluation showed that the approach could be used for initial simulation model generation.

Simulation and forecasting of digital pricing models for an e-procurement platform using an agent-based simulation model

Online businesses can be represented as a complex interaction of interconnected online users responding to the value proposition of an online company. We propose a Dynamic Agent-Based Modeling framework (DYNAMOD) that aims to explain these complex dynamics. This framework aids in the creation of simulation models that mimic the actual market behavior and perform business forecasting and decision support functions. Through a case study of the largest e-procurement provider in Portugal – Vortal.biz, we simulate their pricing model and analyze revenue impact by optimizing pricing using genetic algorithms. The objective of this research is to propose agent-based model as an effective method to forecast the impact of pricing decisions.

ANALYSIS OF EXISTING METHODS AND MODELS WHEN RATIONALE OF ORGANIZATIONAL-TECHNOLOGICAL SOLUTIONS OF CONSTRUCTION OBJECTS

Purpose. A purpose to analyses methods and models, which ground the organization and technology decisions of building of objects, in particular, bridges and transporting tunnels, is put in the article. Methodology. A normative document which is used presently has whole row failings, conditioned by imperfection of information, arbitrariness of form of presentation of information, besides practically does not take into account the requirements of automation. In modern conditions of construction on the optimality of organizational and technological solutions to a variety of factors, some of which are the causes of risk, and the second arises as measures to reduce the impact of the risk. These circumstances require the development of an effective system that minimizes their impact on the selection of optimal organizational and technological solutions. To minimize the time and cost of construction for a given quality of construction works based on the selected methods of organization and technology of production of construction works. Findings. The creation of modern simulation models based on engineering principles that will allow to create optimal conditions to address the complex issues of the reliability of organizational and technological solutions in the construction of objects, in particular, bridges and transporting tunnels. Originality. Has been proved in the conditions of market relations the optimality of organizational and technological solutions can only be achieved at the account of risks arising from changes in the organizational and technological environment of project and construction organizations and other participants of investment and construction activities. Practical value. A simulation technique, which creates additional possibility at estimation of risk due to that does possible appearance of casual scenarios, has developed.

Gekoppelte CFD-DEM-Simulation des Trennprozesses in Mähdrescherreinigungsanlagen

Der vorliegende Artikel befasst sich mit der Anwendung der gekoppelten CFD-DEM-Methode (CFD – Computational Fluid Dynamics; DEM – Discrete Element Method) zur Simulation des Trennprozesses von Korn und NKB (Nichtkornbestandteile) in der Reinigungsanlage des Mahdreschers. Die Vielzahl der Einflussfaktoren, deren Wechselwirkungen, die breite Streuung von Eigenschaften, welche fur biogene Partikel typisch sind, und die daraus resultierende Komplexitat des Trennprozesses erfordern einen strategischen Ansatz zur Erstellung eines validen Simulationsmodells. Die in diesem Artikel vorgestellte Studie untersucht den Trennprozess daher auf zwei Ebenen, welche sich durch den Grad der Prozessabstraktion unterscheiden. Durch den Vergleich der numerischen Ergebnisse mit entsprechenden experimentell gewonnenen Ergebnissen wird die Anwendbarkeit des numerischen Verfahrens bestatigt. Es konnen jedoch auch Abweichungen identifiziert werden, die die Notwendigkeit weiterer Forschung zur Verbesserung der Parametrierung und Modellierung unterstreichen.

Carrier Rotation Strategies for Equal Power Distributions in Cascaded H-Bridge Multilevel Inverters

AbstractMulticarrier pulse width modulation (MC-PWM) techniques such as Level-shifted PWM (LS-PWM) and Phase-shifted PWM (PS-PWM) are the popular methods to control the output voltage of Multilevel Inverters (MLIs). The advantage of LS-PWM techniques over PS-PWMs is that they produce better harmonic profile, but the un-equal power distribution problem of LS-PWMs imposes limitation to their usage in high power and medium voltage applications. For achieving the equal conduction periods and to evenly distribute the power among different cells, carrier rotation should be employed in LS-PWM. This paper proposes two rotation schemes introduced to LS-PWM for producing the collective benefit of equal power distribution from PS-PWM and better harmonic profile from LS-PWM. MATALB/Simulink has been used to create simulation models and the experimental validations are performed by a hardware setup using dSPACE-DS1104 R&D Controller board. Furthermore, experimental results of device conduction periods, conduction losses of individual cells, total harmonic distortions (THDs) and fundamental output voltages have been measured. The effectiveness of proposed methods are verified by comparing the obtained results with traditional MC-PWM techniques.

Secondary use of electronic health record data for clinical workflow analysis.

Outpatient clinics lack guidance for tackling modern efficiency and productivity demands. Workflow studies require large amounts of timing data that are prohibitively expensive to collect through observation or tracking devices. Electronic health records (EHRs) contain a vast amount of timing data - timestamps collected during regular use - that can be mapped to workflow steps. This study validates using EHR timestamp data to predict outpatient ophthalmology clinic workflow timings at Oregon Health and Science University and demonstrates their usefulness in 3 different studies. Four outpatient ophthalmology clinics were observed to determine their workflows and to time each workflow step. EHR timestamps were mapped to the workflow steps and validated against the observed timings. The EHR timestamp analysis produced times that were within 3 min of the observed times for >80% of the appointments. EHR use patterns affected the accuracy of using EHR timestamps to predict workflow times. EHR timestamps provided a reasonable approximation of workflow and can be used for workflow studies. They can be used to create simulation models, analyze EHR use, and quantify the impact of trainees on workflow. The secondary use of EHR timestamp data is a valuable resource for clinical workflow studies. Sample timestamp data files and algorithms for processing them are provided and can be used as a template for more studies in other clinical specialties and settings.

Evaluation of Three-Dimensional Printed Materials for Simulation by Computed Tomography and Ultrasound Imaging.

The use of three-dimensional (3D) printing allows for creation of custom models for clinical care, education, and simulation. Medical imaging, given the significant role it plays in both clinical diagnostics and procedures, remains an important area for such education and simulation. Unfortunately, the materials appropriate for use in simulation involving radiographic or ultrasound imaging remains poorly understood. Therefore, our study was intended to explore the characteristics of readily available 3D printing materials when visualized by computed tomography (CT) and ultrasound. Seven 3D printing materials were examined in standard shapes (cube, cylinder, triangular prism) with a selection of printing methods ("open," "whole," and "solid" forms). For CT imaging, these objects were suspended in a gelatin matrix molded to match a standard human CT phantom. For ultrasound imaging, the objects were placed in acrylic forms filled with a gelatin matrix. All images were examined using OsiriX software. Computed tomography imaging revealed marked variation in materials' Hounsfield units as well as patterning and artifact. The Hounsfield unit variations revealed a number of materials suitable for simulation various human tissues. Ultrasound imaging showed echogenicity in all materials, with some variability in shadowing and posterior wall visualization. We were able to demonstrate the potential utility for 3D printing in the creation of CT and ultrasound simulation models. The similar appearance of materials via ultrasound supports their broad utility for select tissue types, whereas the more variable appearance via CT suggests greater potential for simulating differing tissues but requiring multiple printer technologies to do so.

Comparison of SRF/PI- and STRF/PR-based power controllers for grid-tied distributed generation systems

Grid-tied distributed generation (DG) system-based renewable energy sources such as wind, sun and hydrogen have recently gained a large attention due mainly to environmental issues. In this study, to provide energy for various loads, it is connected to the common direct current bus system after DG system-based fuel cell and solar cell are modeled and simulated. In order to synchronize DG system sources to utility grid, park transformation-based three-phase phase-locked loop technique is used, which is one of the most common methods in the literature. Power control method-based synchronous reference frame with proportional integral controller or stationary reference frame with proportional resonant current controller is used in the DG systems. The performances of two controllers are discussed in this study. Simulation results are obtained for various scenarios at the designed and created simulation model of DG + Grid + Load system. The system is modeled and simulated by using PSCAD/EMTDC software package.

Emulation of control strategies through machine learning in manufacturing simulations

Discrete-event simulation is a well-accepted method for planning, evaluating, and monitoring processes in production and logistics. To reduce time and effort spent on creating simulation models, automatic simulation model generation is an important area in modeling methodology research. When automatically generating a simulation model from existing data sources, the correct reproduction of dynamic behavior of the modeled system is a common challenge. One example is the representation of dispatching and scheduling strategies of production jobs. When generating a model automatically, the underlying rules for these strategies are typically unknown but yet have to be adequately emulated. In this paper, we summarize our work investigating the suitability of various data mining and supervised machine learning methods for emulating job scheduling decisions based on data obtained from production data acquisition. We report on the performance of the algorithms and give recommendations for their application, including suggestions for their integration in simulation systems.

Experimental determination of soil electrical parameters for the creation of a computer model of a grounding system for lightning protection

The paper presents multifactor experimental studies for determining the apparent soil resistivity and the dielectric permittivity depending on the frequency of the electromagnetic field, the multilayered structure, moisture content and density of the soil. The gravimetric method for considering the soil moisture during the experimental researches was chosen. The received experimental results were statistically processed and a mathematical modelling of the controlled parameters was performed considering the specifics of the examined soil. These analytically obtained results of the dependences would contribute to more precise sizing of the grounding systems and could be used for creation of accurate simulation models for the study of wave processes in them.

Fading Channels Parametric Data Simulation Supported by Real Data from Outdoor Experiments

Optimizing the estimates of received power signals is important as it can improve the process of transferring an active call from one base station in a cellular network to another base station without any interruptions to the call. The lack of effective techniques for estimation of shadow power in fading mobile wireless communication channels motivated the use of Kalman Filtering (KF) as an effective alternative. In our research, linear second-order state space Kalman Filtering was further investigated and tested for applicability. We first created simulation models for two KF-based estimators designed to estimate local mean (shadow) power in mobile communications corrupted by multipath noise. Simulations were used extensively in the initial stage of this research to validate the proposed method. The next challenge was to determine if the models would work with real data. Therefore, in [1] we presented a new technique to experimentally characterize the wireless small-scale fading channel taking into consideration real environmental conditions. The two-dimensional measurement technique enabled us to perform indoor experiments and collect real data. Measurements from these experiments were then used to validate simulation models for both estimators. Based on the indoor experiments, we presented new results in [2], where we concluded that the second-order KF-based estimator is more accurate in predicting local shadow power profiles than the first-order KF-based estimator, even in channels with imposed non-Gaussian measurement noise. In the present paper, we extend experiments to the outdoor environment to include higher speeds, larger distances, and distant large objects, such as tall buildings. Comparison was performed to see if the system is able to operate without a failure under a variety of conditions, which demonstrates model robustness and further investigates the effectiveness of this method in optimization of the received signals. Outdoor experimental results are provided. Findings demonstrate that the second-order Kalman filter outperforms the first-order Kalman filter.

Fire Spread Models and Tunnel Traffic & Operation Simulator

The computer simulation of fire spread based on modelling of complex processes related to fire by Computer Fluid Dynamics CFD theory should be a significant contribution to increase of safety of road tunnels. This paper is about instant project aimed at creating simulation models of formation and spread of fires in the road tunnel. The simulations will be compared with real in-situ measurements of fire scenarios suggested by customer organization in two road tunnels. Within the project, Tunnel Traffic and Operation Simulator, as unique facility at University of Žilina will be extended by visualizations of smoke stratification in the virtual tunnel tube.