scholarly journals Simulation-based what-if analysis for controlling the spread of Covid-19 in universities

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0246323
Author(s):  
Navid Ghaffarzadegan
Keyword(s):  
Unintended Consequences ◽  
Proof Of Concept ◽  
Implementation Challenges ◽  
Long Run ◽  
Simulation Based ◽  
Rapid Tests ◽  
Simulation Results ◽  
Marginal Effectiveness ◽  
Remote Operations ◽  
Silver Bullet

A simulation model is developed to analyze the spread of covid-19 in universities. The model can be used to conduct a what-if analysis and estimate infection cases under different policies. For proof-of-concept, the model is simulated for a hypothetical university of 25,000 students and 3,000 faculty/staff in a U.S. college town. Simulation results show that early outbreaks are very likely, and there is no silver bullet to avoid them. Instead, a combination of policies should be carefully implemented. The results suggest (almost) full remote university operations from the beginning of the semester. In a less-preferred alternative, if universities decide to have students attend in person, they should encourage remote operations for high-risk individuals, conduct frequent rapid tests, enforce mask use, communicate with students and employees about the risks, and promote social distancing. Universities should be willing to move to remote operations if cases rise. Under this scenario, and considering implementation challenges, many universities are still likely to experience an early outbreak, and the likelihood of having a case of death is worrisome. In the long run, students and faculty react to the risks, and even if universities decide to continue operations, classes are likely to have very low in-person attendance. Overall, our analysis depicts several sources of system complexities, negative unintended consequences of relying on a single policy, non-linear incremental effects, and positive synergies of implementing multiple policies. A simulation platform for a what-if analysis is offered so marginal effectiveness of different policies and different decision-making thresholds for closure can be tested for universities of varying populations.

Study on Engine Kinematics and Dynamics Simulation Based on COSMOSMotion

2012 ◽  
Vol 503-504 ◽  
pp. 731-734
Author(s):  
Xiao Xu Liu ◽  
Min Chen ◽  
Ai Hua Tang
Keyword(s):  
Virtual Prototype ◽  
Dynamics Simulation ◽  
Kinematics And Dynamics ◽  
Engine Model ◽  
Kinematics Simulation ◽  
Simulation Based ◽  
Calculation Results ◽  
Simulation Results ◽  
Dynamics Simulations

The engine model with 4 cylinders is built by SolidWorks, the kinematics and dynamics simulations of the engine virtual prototype are done by COSMOSMotion, the results of kinematics simulation are checked, there are very small errors between the simulation results and the calculation results according to formulas. The mainly results of dynamics simulation are given. The simulation result consists with the parameters of the engine.

Numerical Simulation on Thixo-Forging of Magnesium Matrix Composite

2011 ◽  
Vol 189-193 ◽  
pp. 2535-2538 ◽  
Author(s):  
Hong Yan ◽  
Wen Xian Huang
Keyword(s):  
Numerical Simulation ◽  
Matrix Composite ◽  
Metal Flow ◽  
Magnesium Matrix Composite ◽  
Magnesium Matrix ◽  
Simulation Based ◽  
Prior Literature ◽  
Simulation Results ◽  
Computer Numerical Simulation ◽  
Good Agreement

The thixo-forging of magnesium matrix composite was analyzed with computer numerical simulation based on rigid viscoplastic finite element method. The constitutive model of SiCp/AZ61 composite was established in our prior literature. Behavior of metal flow and temperature field were obtained. The differences between traditional forging and thixo-forging processes were analyzed. Results indicated that thixo-forging was better in filling cavity than forging. Simulation results were good agreement with experimental ones.

MERGE OF THE TECHNİCAL ANALYSİS TYPES GİVES THE BEST RESULTS İN CRYPTOCURRENCY MARKET

2021 ◽  
Vol 6 (14) ◽  
pp. 89-97
Author(s):  
MUSTAFA ÖZYEŞİL ◽  
MOHAMMAD AL-TARIFI
Keyword(s):  
Supply And Demand ◽  
Investment Strategy ◽  
Proof Of Concept ◽  
Market Capitalization ◽  
Long Run ◽  
Peer Network ◽  
Tangible Asset ◽  
The Relationship ◽  
Peer To Peer Network

Cryptocurrencies are a modern kind of financial instrument (Hudson & Urquhart, 2019), the first cryptocurrency is Bitcoin , proposed by who called Satoushi Nakamato (2008), as The open source was created on the proof-of-concept principle that transactions can be securely treated on a decentralized peer to peer network without the need for a central clearinghouse, which appeared 2009 ( Heid, 2013). The success of the bitcoin blazes a trail to what called ‘Altcoin” this expression means all the cryptocurrencies that set in motion after the victory of the bitcoin, these coins sell themselves as the best alternatives for the bitcoin (FRANKENFIELD, 2020) . There are many types for the altcoin. The third type of the cryptocurrency is called Tokens Unlike Bitcoin and Altcoins, tokens are not able to activate independently and are dependent on the grid of another cryptocurrency. That means they do not have their own core DLT or blockchain, but instead, are built on top of an existing cryptocurrency’s blockchain (Types of cryptocurrencies: explaining the major types of cryptos, 2019). The worth of bitcoin doesn’t depend on any tangible asset or economies of the countries while it is based upon the security of an algorithm which traces all transactions (Hudson & Urquhart, 2019). The studies determine the number of the bitcoin price development in the long -run (Ciaian, Rajcaniova, & Kancs, 2018): • Market forces of the Bitcoin supply and demand • The bitcoin’s attractiveness for the investors • The influence of global macro-financial developments If you're forming an investment strategy designed to help you trail long-term financial intentions, understanding the relationship between company size, return potential, and risk is vital. (Market cap—or market capitalization—refers to the total value of all a company's shares of stock, 2017) .Hence , Manifested importance a cryptocurrency’s market capitalization as the total values of all coins currently in circulation. the cryptocurrency’s market cap contains what’s called Bitcoin Dominance that is the ratio between the market cap of bitcoin to other coins of the cryptocurrency markets (jacobcanfield, 2019) . Cryptocurrency trade is attractive type of investment. this market treated the same of the foreign exchange and stock market ( Radityo, Munajat, & Budi, 2017). The investors using the same basic in investment (buy low, sell high) but they need to calculating the risks

Reliability-Based Analysis and Optimization of the Gravity Balancing Performance of Spring-Articulated Serial Robots with Uncertainties

2021 ◽  
pp. 1-32
Author(s):  
Vu Linh Nguyen ◽  
Chin-Hsing Kuo ◽  
Po Ting Lin
Keyword(s):  
Pso Algorithm ◽  
Reliability Based Design Optimization ◽  
Swarm Optimization ◽  
Reliability Based Design ◽  
Serial Robots ◽  
Simulation Based ◽  
Serial Robot ◽  
Simulation Results ◽  
Uncertainty Level

Abstract This article proposes a method for analyzing the gravity balancing reliability of spring-articulated serial robots with uncertainties. Gravity balancing reliability is defined as the probability that the torque reduction ratio (the ratio of the balanced torque to the unbalanced torque) is less than a specified threshold. The reliability analysis is performed by exploiting a Monte Carlo simulation (MCS) with consideration of the uncertainties in the link dimensions, masses, and compliance parameters. The gravity balancing begins with a simulation-based analysis of the gravitational torques of a typical serial robot. Based on the simulation results, a gravity balancing design for the robot using mechanical springs is realized. A reliability-based design optimization (RBDO) method is also developed to seek a reliable and robust design for maximized balancing performance under a prescribed uncertainty level. The RBDO is formulated with consideration of a probabilistic reliability constraint and solved by using a particle swarm optimization (PSO) algorithm. A numerical example is provided to illustrate the gravity balancing performance and reliability of a robot with uncertainties. A sensitivity analysis of the balancing design is also performed. Lastly, the effectiveness of the RBDO method is demonstrated through a case study in which the balancing performance and reliability of a robot with uncertainties are improved with the proposed method.

scholarly journals Multi-Perspective Modeling of Healthcare Systems

2017 ◽  
Vol 5 (2) ◽  
pp. 1-20 ◽  
Author(s):  
Ignace Djitog ◽  
Hamzat Olanrewaju Aliyu ◽  
Mamadou Kaba Traoré
Keyword(s):  
Specific Problem ◽  
Discrete Event ◽  
Healthcare Systems ◽  
Proof Of Concept ◽  
System Specification ◽  
Disease Propagation ◽  
Dynamic Update ◽  
Event System ◽  
Simulation Based

This paper presents a multi-perspective approach to Modeling and Simulation (M&S) of Healthcare Systems (HS) such that different perspectives are defined and integrated together. The interactions between the isolated perspectives are done through dynamic update of models output-to-parameter integration during concurrent simulations. Most often, simulation-based studies of HS in the literature focus on specific problem like allocation of resources, disease propagation, and population dynamics that are studied with constant parameters from their respective experimental frames throughout the simulation. The proposed idea provides a closer representation of the real situation and helps to capture the interactions between seemingly independent concerns - and the effects of such interactions - in simulation results. The article provides a DEVS (Discrete Event System Specification)-based formalization of the loose integration of the different perspectives, an Object-Oriented framework for its realization and a case study as illustration and proof of concept.

scholarly journals DETECTION OF FUNCTIONAL FORM MISSPECIFICATION IN COINTEGRATING RELATIONS

2008 ◽  
Vol 24 (5) ◽  
pp. 1373-1403 ◽  
Author(s):  
Ioannis Kasparis
Keyword(s):  
Functional Form ◽  
Simulation Experiment ◽  
Cusum Test ◽  
Specification Test ◽  
Cumulative Sum ◽  
Finite Samples ◽  
Long Run ◽  
Simulation Results

A simple specification test based on fully modified residuals and the cumulative sum (CUSUM) test for cointegration of Xiao and Phillips (2002, Journal of Econometrics, 108, 43–61) are considered as means of testing for functional form in long-run cointegrating relations. It is shown that both tests are consistent under functional form misspecification and lack of cointegration. A simulation experiment is carried out to assess the properties of the tests in finite samples. The Dickey–Fuller test is also considered. The simulation results reveal that the first two tests perform reasonably well. However, the Dickey–Fuller test performs poorly under functional form misspecification.

scholarly journals Hybrid LWFA–PWFA staging as a beam energy and brightness transformer: conceptual design and simulations

2019 ◽  
Vol 377 (2151) ◽  
pp. 20180175 ◽  
Author(s):  
A. Martinez de la Ossa ◽  
R. W. Assmann ◽  
M. Bussmann ◽  
S. Corde ◽  
J. P. Couperus Cabadağ ◽  
...  
Keyword(s):  
Conceptual Design ◽  
Particle Beam ◽  
Proof Of Concept ◽  
Particle In Cell ◽  
Wakefield Acceleration ◽  
Plasma Wakefield Accelerator ◽  
Simulation Results ◽  
Set Up ◽  
Plasma Wakefield ◽  
Wakefield Accelerator

We present a conceptual design for a hybrid laser-driven plasma wakefield accelerator (LWFA) to beam-driven plasma wakefield accelerator (PWFA). In this set-up, the output beams from an LWFA stage are used as input beams of a new PWFA stage. In the PWFA stage, a new witness beam of largely increased quality can be produced and accelerated to higher energies. The feasibility and the potential of this concept is shown through exemplary particle-in-cell simulations. In addition, preliminary simulation results for a proof-of-concept experiment in Helmholtz-Zentrum Dresden-Rossendorf (Germany) are shown. This article is part of the Theo Murphy meeting issue ‘Directions in particle beam-driven plasma wakefield acceleration’.

Study on flow field of gas–solid two-phase pulsed jet

2019 ◽  
Vol 33 (24) ◽  
pp. 1950279
Author(s):  
Xinhua Song ◽  
Xiaojie Li ◽  
Yang Wang ◽  
Honghao Yan
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Particle Distribution ◽  
Starch Granule ◽  
Injection Pressure ◽  
Two Phase ◽  
Particle Injection ◽  
Pulsed Jet ◽  
Simulation Based ◽  
Simulation Results

In this paper, a computational fluid dynamics–discrete element method (CFD–DEM) coupling method is established to simulate the starch granule injection by coupling CFD and DEM. Then a gas–solid two-phase pulsed jet system is designed to capture the flow field trajectory of particle injection (colored starch with a mean diameter of 10.67 [Formula: see text]m), and the image is processed by color moment and histogram. Finally, the simulation results are compared with the experimental results, and the following conclusions are drawn. The numerical simulation results show that with the increase of injection pressure, the injection height increases gradually. When the injection pressure reaches above 0.4 MPa, the increase of injection height decreases. The experimental images show that the larger the pressure (i.e., the greater the initial velocity), the faster the velocity of particle distribution in the space, and the injection heights with the injection pressures of 0.4 MPa and 0.5 MPa are close, which is consistent with the result from the FLUENT numerical simulation based on CFD–DEM.

A Novel 3-DOF Parallel Robot and its Kinematic Analysis

2014 ◽  
Vol 607 ◽  
pp. 759-763
Author(s):  
Xiao Bo Liu ◽  
Xiao Dong Yuan ◽  
Xiao Feng Wei ◽  
Wei Ni
Keyword(s):  
Motion Control ◽  
Kinematic Analysis ◽  
Degrees Of Freedom ◽  
Parallel Robot ◽  
Degree Of Freedom ◽  
The Novel ◽  
Forward Displacement ◽  
Simulation Based ◽  
Simulation Results

This paper deals with the design and analysis of a novel and simple two-translation and one-rotation (3 degrees of freedom, 3-dof) mechanism for alignment. Firstly, degree of freedom of the parallel robot is solved based on the theory of screw. Secondly considering the demand of motion control, we have conducted the analysis on the 3-dof parallel robot, which includes inverse displacement, forward displacement, and simulation based on SolidWorks Motion. The simulation results indicate that the novel 3-dof robot is suitable for performing the required operations.

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