Design Of Simulation Model Research Articles

A simulation model for continuous autofocus design

The design of continuous autofocus algorithms often involves repetitive, time-consuming field tests on real scenes. This paper presents a simulation method to expedite the design by replacing laborious field tests with simulation tests. The modeling of scene dynamics is achieved by decomposing a dynamic scene into a sequence of static scenes and representing the sharpness responses of the video camera to each static scene by a reciprocal focus profile. Three different scenes and the associated dynamic models are incorporated into the simulation framework to obtain effective clues for the refinement of continuous autofocus algorithms. Experimental results are provided to show the effectiveness of this design-by-simulation method.

Applied Simulation Model for Design of Improving Medical Record Area in Out-patient Department (OPD) of a Governmental Hospital

This article presents a method for design of improving medical record area in OPD of a governmental hospital case study, Mahasarakham Hospital, Thailand. By using a simulation model which is Petri Nets model for simulating and analysis of coming patients and their relatives in the hospital case study during 6:30-16:00 of the working days. Results found the application was applicable. Recommendations in the design of improving the waiting area case study were discussed and presented in this research.

A Modeling Method for HVDC Control on RTDS Simulation

Converter control model plays an essential function for HVDC system dynamic simulation in real time simulator (RTDS). RTDS can provide approach for detailed studies of options and predictions of the system performance. This paper first presents the basic principle of the power control, firing control and transformer tap control. Then the paper presents our modeling effort for these control models. The configuration of control models includes major sections of practical controls. The paper also makes final verification test of these sections with a typical power system model. The validity of proposal methods and designed simulation model is verified by tests and computed results. The built HVDC control model is competent for the RTDS simulation.

The Simulation Research of Self-Excited Startup for Wind Generator Based on RTDS

Concerned that wind generators start up and establish the stable terminal voltage of the stator which is connected to the grid, this paper presents that wind generator can be operated as the independent generator at a certain voltage and frequency by means of capacitive excitation. The paper also deduces the calculation method for the proper capacitance value of self-exciting startup of wind generator. The paper builds a simulation model based on real time digital simulator (RTDS) and takes a case for simulating self-excited startup of wind generator. Simulation results demonstrate that the wind generator with self-excitation can successfully start up and be connected to the grid, it make a good agreement of actual situation. Furthermore, the results of RTDS simulation show that only proper capacitors value from optimized calculation can lead to a normal terminal voltage characteristic. The validity of proposal methods and designed simulation model is verified by experimental and computed results.

High Efficiency Cu(In,Ga)Se2 Flexible Solar Cells Fabricated by Roll-to-Roll Metallic Precursor Co-sputtering Method

We report on a Cu(In,Ga)Se2 (CIGS) solar cell fabricated on flexible stainless steel substrate by a low cost mass production roll-to-roll process. Fabricated device has a high energy conversion efficiency of 14%, with short circuit current density (Jsc) of 36.6 mA cm-2 and open circuit voltage (Voc) of 0.55 V. A two-dimensional (2D) simulation model for CIGS solar cell design and optimization was proposed. Opto-electrical properties showed that both experimental and simulated results are consistent with each other. The photons absorber in CIGS solar cells was prepared by co-sputtering metallic precursors of In and CuGa followed by thermal annealing in Se vapor. The device chemical properties were analyzed by secondary ion mass spectrometry (SIMS) and transmission/scan electron microscopy (TEM/SEM). Indium and gallium interdiffusions were observed during the growth of film, forming a band grading in CIGS layer. Accumulation of In at the top CIGS surface, resulting in a low bandgap, was responsible for the limited output open circuit voltage. Nano-scale voids were observed in the grown CIGS layer. A model based on Kirkendal effect and interdiffusion of atoms during selenization is developed to explain the formation mechanism of these voids. Na and K incorporation as well as metallic impurities diffusion are also discussed.

유한요소 해석기법을 이용한 탄소복합소재 인공발의 설계

The dynamic compliance characteristics of a prosthetic foot midgait are very important for natural performance in an amputee’s gait and should be in a range that provides natural, stable walking. In this study, finite element analysis (FEA) and classical laminate theory were used to examine the mechanical characteristics of a carbon-epoxy composite laminate prosthetic foot as a function of variation in the lamination composition. From this analysis, an FEM model of a prosthetic keel, made from the composite material, was developed. The lamination composition of the keel was designed for improved stiffness. The prototype product was fabricated using an autoclave. Vertical loading response tests were performed to verify the simulation model. The results of the experiments were similar to those from simulations below the loading level of the gait, suggesting use of the proposed simulation model for prosthetic keel design.

A New Simulation Model for Design of Distillation Column in a Bio-ethanol/Water System: Effect of Reflux Ratio

Fuel ethanol research development deals with process design integration for improving production of ethanol. This paper investigates the effect of variable reflux ratio on the design of distillation column using developed JAVA based simulation software. This was done by varying reflux ratio as an input parameter and observed the effect it has on the number of trays that produced the column height. Varying reflux ratio arbitrarily from 3.094 to 9.301 produced column height ranging between 5.897 and 6.232 respectively. With the feed composition of ethanol -water mixture set at 45 percent, and the minimum reflux ratio of 3.4. The results showed that th e number of trays decreases with increase in reflux ratio

レーシングカート操縦シミュレーション·モデルとドライビング·エージェントの構成

レーシングカート操縦シミュレーション·モデルとドライビング·エージェントの構成

A Simulation Model Design Method for Cloud-Based Simulation Environment

Simulation technologies provide necessary validation tools for the conceptual design of complex products involving multiple disciplines. A variety of simulation models are developed in specific organizations or enterprises to verify the design plan, while they are hard to be shared and to be reused. Based on the analysis of several typical solutions to share and reuse different kinds of resources, a simulation model design method is proposed to provide a simple implementation of simulation model reuse for cloud-based simulation environment. This paper firstly creates the simulation models' metamodel and ontology for their universal description. Secondly, four rules are proposed to design/reprogram a simulation model into service-oriented form for its interoperability, and the ontology of service-oriented simulation model is established. Thirdly, the way to call one simulation model and the way to compose several simulation models into a simulation process are elaborated. Finally, a simple case of using this method to design an aircraft dynamic model is elaborated, and a prototype simulation system is constructed, and then a simple simulation process is composed to verify the practicability of the method. The result shows that the new design/reprogram method has big advantages on the compatibility, expansibility, and reusability despite the decreasing efficiency.

A Fuzzy Logic Based on Theoptimal Energy Conservation with Human Satisfaction of the Inverter Air Conditioning System for Tropical Area

This research is study of the air conditioning by used fuzzy logic control to analysis. It will take into account the energy savings and the room temperature remained in range of comfort zone for the resident's satisfaction. To control % AC compressor and fan speed. The system was simulated and designed simulation model of fuzzy logic controlled on Matlab program to monitor energy consumption and temperature of the room. The results indicate that thermal comfort of the room together with energy saving can be obtained through fuzzy logic controlled .At a temperature setting of 25 °C and defined heat load in the room, the energy saving for the system is calculated to 30.77 % for fuzzy controllers when compared with on-off condition.

Evacuation Simulation Model for Large Hotel Based on GIS

To meet the requirements of emergency evacuation in a large hotel, this paper introduces design and implementation of emergency evacuation simulation model for a large hotel based on GIS in detail. Firstly, the design of the simulation model is introduced in the paper. Four-tier framework of the model is composed of user layer, application layer, underlying support layer and data layer. Secondly, the key technologies of the model are emphasized. The spatial analysis and attribute data analysis of GIS are used to determine evacuation zone of emergencies and disasters in a large hotel and achieve the optimal emergency evacuation plan for crowd. Finally, test results showed the model improves the simulation precision and can provide effective service for emergency evacuation in a large hotel.

The effects of indoor environmental exposures on pediatric asthma: a discrete event simulation model.

BackgroundIn the United States, asthma is the most common chronic disease of childhood across all socioeconomic classes and is the most frequent cause of hospitalization among children. Asthma exacerbations have been associated with exposure to residential indoor environmental stressors such as allergens and air pollutants as well as numerous additional factors. Simulation modeling is a valuable tool that can be used to evaluate interventions for complex multifactorial diseases such as asthma but in spite of its flexibility and applicability, modeling applications in either environmental exposures or asthma have been limited to date.MethodsWe designed a discrete event simulation model to study the effect of environmental factors on asthma exacerbations in school-age children living in low-income multi-family housing. Model outcomes include asthma symptoms, medication use, hospitalizations, and emergency room visits. Environmental factors were linked to percent predicted forced expiratory volume in 1 second (FEV1%), which in turn was linked to risk equations for each outcome. Exposures affecting FEV1% included indoor and outdoor sources of NO2 and PM2.5, cockroach allergen, and dampness as a proxy for mold.ResultsModel design parameters and equations are described in detail. We evaluated the model by simulating 50,000 children over 10 years and showed that pollutant concentrations and health outcome rates are comparable to values reported in the literature. In an application example, we simulated what would happen if the kitchen and bathroom exhaust fans were improved for the entire cohort, and showed reductions in pollutant concentrations and healthcare utilization rates.ConclusionsWe describe the design and evaluation of a discrete event simulation model of pediatric asthma for children living in low-income multi-family housing. Our model simulates the effect of environmental factors (combustion pollutants and allergens), medication compliance, seasonality, and medical history on asthma outcomes (symptom-days, medication use, hospitalizations, and emergency room visits). The model can be used to evaluate building interventions and green building construction practices on pollutant concentrations, energy savings, and asthma healthcare utilization costs, and demonstrates the value of a simulation approach for studying complex diseases such as asthma.

Simulation Model for Design of a New Power Supply

The simulation model for a new power supply of the injection bump system magnets [1]-[4] of the 3-GeV RCS (Rapid Cycling Synchrotron) in J-PARC (Japan Proton Accelerator Complex) [5], [6] has been constructed. The new power supply requires the reduction of the ripple noise current which will resonate with load and excites a forced beam oscillation at 96 kHz in the injection stage. In order to incorporate the load impedance in the simulation model, the impedances of a feeder line and the bump magnet with a ceramic vacuum chamber [7] inside were measured. The RF shield is formed on the ceramic surface along the beam direction. The results were successfully analysed using the OPERA-3D [8] and the circuit simulation code, Micro-Cap [9], and showed a good agreement. It was found the RF shield of a ceramic chamber has a resonant structure corresponding to 96 kHz.

FUZZY LOGIC BASED UNCERTAINTY REPRESENTATION AND SIMULATION IN A FLEXIBLE ASSEMBLY SYSTEM

This paper provides intelligent simulation approach using manufacturing uncertainty in the form of simulation intelligence to improve the performances of manufacturing production system. It shows how simulation can be used to evaluate alternative designs in an uncertain manufacturing environment. Fuzzy rule-based manufacturing uncertainties are addressed in this study. A combination of product mix and production volume is analyzed using intelligent simulation model for an optimal production design. The intelligent simulation approach would improve the modeling accuracy in terms of more realistic presentation of uncertain activities. The proposed intelligent simulation modeling shows significant improvement and validated with real life application.

Linking Six Sigma to simulation: a new roadmap to improve the quality of patient care

Improving the quality of patient care is a challenge that calls for a multidisciplinary approach, embedding a broad spectrum of knowledge and involving healthcare professionals from diverse backgrounds. The purpose of this paper is to present an innovative approach that implements discrete-event simulation (DES) as a decision-supporting tool in the management of Six Sigma quality improvement projects. A roadmap is designed to assist quality practitioners and health care professionals in the design and successful implementation of simulation models within the define-measure-analyse-design-verify (DMADV) or define-measure-analyse-improve-control (DMAIC) Six Sigma procedures. A case regarding the reorganisation of the flow of emergency patients affected by vertigo symptoms was developed in a large town hospital as a preliminary test of the roadmap. The positive feedback from professionals carrying out the project looks promising and encourages further roadmap testing in other clinical settings. The roadmap is a structured procedure that people involved in quality improvement can implement to manage projects based on the analysis and comparison of alternative scenarios. The role of Six Sigma philosophy in improvement of the quality of healthcare services is recognised both by researchers and by quality practitioners; discrete-event simulation models are commonly used to improve the key performance measures of patient care delivery. The two approaches are seldom referenced and implemented together; however, they could be successfully integrated to carry out quality improvement programs. This paper proposes an innovative approach to bridge the gap and enrich the Six Sigma toolbox of quality improvement procedures with DES.

Sensorimotor integration during stance: Processing time of active or passive addition or withdrawal of visual or haptic information

Vision (V) and touch (T) help stabilize our standing body, but little is known on the time-interval necessary for the brain to process the sensory inflow (or its removal) and exploit the new information (or counteract its removal). We have estimated the latency of onset and the time-course of the changes in postural control mode following addition or withdrawal of sensory information and the effect of anticipation thereof.Ten subjects stood in tandem position. They wore LCD goggles that allowed or removed vision, or lightly touched (eyes-closed) with the index finger (haptic stimulation) a pad that could be suddenly lowered (passive task). In different sessions, sensory shifts were deliberately produced by opening (or closing) the eyes or touching the pad (or lifting the finger) (active task). We recorded eyelid movement and finger force (<1N), sway of center of foot pressure (CoP), electromyogram (EMG) of soleus, tibialis and peroneus muscle, bilaterally, and of extensor indicis. The latency of the CoP and EMG changes following the shifts were statistically estimated on the averaged traces of 50 repetitions per condition.Muscle activity and sway adaptively decreased in amplitude on adding stabilizing visual or haptic information. The time-interval from the sensory shift to decrease in EMG and sway was ∼0.5–2s under both conditions. It was shorter for tibialis than peroneus or soleus and shorter for visual than haptic shift. CoP followed the tibialis by ∼0.2s. Slightly shorter intervals were observed following active sensory shifts. Latencies of EMG and postural changes were the shortest on removal of both haptic and visual information. Subsequently, the time taken to reach the steady-state was ∼1–3s under both active and passive tasks. A startle response at ∼100ms could precede EMG changes. Reaction-time contractions in response to sensory shifts appeared at ∼200ms, earlier than the adaptive changes.Changes in postural behavior require a finite amount of time from visual or haptic shift, much longer than reflexes or rapid voluntary responses, suggesting a time-consuming central integration process. This process is longer on addition than removal of haptic information, indicating a heavier computational load. These findings should be taken into account when considering problems of sensorimotor integration in elderly subjects or patients and when designing simulation models of human balance.

Experimental Evaluation and Simulation of Al/Si Diffusion in Hot Dipped Fe-Si Steels

Hot dipping is a coating technique used in industry for galvanizing machine elements and steel profiles for construction or automotive applications. However, an alternative use of this process might be to improve specific properties. For instance, in order to improve the magnetic properties of electrical steels, it may be desirable to increase the Si and/or Al content. A possible and alternative route to realize this is by the application of an Al-Si-rich coating on the steel substrate using a hot dipping process, followed by a diffusion annealing treatment in order to distribute the Al/Si more evenly in the steel. The obtained distribution depends on the annealing parameters and can be both beneficial and detrimental for the magnetic properties. In the present work, Fe-Si substrates were hot dipped in different Al-Si baths. Subsequently, the samples were annealed at 1100°C during 20 minutes and concentration profiles were measured with scanning electron microscope energy dispersive spectroscopy line scans. The experimental results were analyzed using a specifically designed simulation model in order to determine the Al and Si diffusion coefficients. This model uses an inverse algorithm to determine interdiffusion coefficients that arise in a macro ternary diffusion system.

Integration of JIT flexible manufacturing, assembly and disassembly using a simulation approach

PurposeIn the real world many companies combine the operations of manufacturing, assembly and disassembly. Thus, the integration of just‐in‐time FMS, FAS, and flexible disassembly system (DAS) models poses an interesting problem. The purpose of this paper is to provide major emphasis on a new simulation model for design and performance evaluation of a flexible assembly and disassembly system with dual Kanban under a stochastic system. This paper also primarily investigates the effect of varying the number of kanban cards, mean inter‐arrival time of demand and locations of the bottlenecks on the performance integration of JIT flexible manufacturing, assembly and disassembly systems.Design/methodology/approachSimulation is carried out in ARENA and data is analyzed using multivariate analysis of variance (MANOVA). This paper investigates the effect of varying number of kanban cards, mean inter‐arrival time of demand, and locations of the bottlenecks on the performance integration of JIT flexible manufacturing, assembly and disassembly systems. The performance measures that are simultaneously considered are the fill rate, work in process, and mean cycle time. This paper emphasizes that understanding the interactions between the variables and their effects on system performance is of utmost importance for managers in improving performance processes.FindingsIn manufacturing practice, there are many industrial units that represent the mixture of the referred three models. This paper presents a new simulation model for design and performance evaluation of a flexible assembly and disassembly system with dual kanban. The simulation results are statistically compared with MANOVA. MANOVA is used to perform the test with multiple objective functions, e.g. with the average production cycle time, percentage average fill rate, and work‐in‐process. The conclusion to be drawn is that minimized WIP can be obtained by higher percentage average fill rate, lower WIP, small average part cycles times, and increasing in kanban cards while simultaneously retaining full customer satisfaction.Originality/valueThe researcher presents the newly developed kanban system into the production system of JIT flexible manufacturing, assembly and disassembly system with simulation technique. Furthermore, by assigning time factors to the models, several performance measures can be easily computed. Then, the researcher tests the effect of the number of kanban card on integration of JIT flexible manufacturing, assembly and disassembly systems using a simulation approach, the simulation model is developed using the ARENA simulation package. The results are applied to a small case study. For a single product under the integration of JIT flexible manufacturing, assembly and disassembly systems, as the number of kanban cards increase, the fill rate along with work in process and the mean cycle time increases as well.

A simulation modelling approach to forecast establishment and spread of Bactrocera fruit flies

This paper reports on the design, construction and testing of a novel simulation model for the establishment and spread of fruit fly. The model permits the investigation of spatio-temporal development of a fruit fly outbreak under variable environmental conditions and taking account of the location, availability and suitability of preferred food, and of the existence of obstacles to spread. Implementation of the simulator is designed to make it suitable for use at various levels of outbreak management and biosecurity. Initial efforts at validating the predictions against actual historical outbreak data indicate that the simulator could be an useful tool to support decision making.

A Whole Body Postural Loading Simulation and Assessment Model for Workplace Analysis and Design

This study reports on the development and validation of a new computer model for simulating human postures at work, and assessing the reaction forces and bending moments in 43 human articulation joints. The proposed model estimates the intradiscal pressure in the vertebral column in response to external loading forces encountered during human interactions with work objects or processes. The model was implemented in a self-contained interactive software package. The simulation results compare favorably with the reported experimental data, and provide reasonable confidence in the quality of the model. Its characteristics and its applications in evaluating physical task performance are also discussed