Martin Bicher

An agent-based epidemic model for dengue simulation in the Philippines

Dengue is a mosquito-borne disease and a severe health issue in tropical and subtropical countries. Based on a literature search and data gathering, an agent-based model for simulating dengue epidemics is developed. It models human and mosquito agents with detailed agents behavior, mosquito biting rules and transmissions. Featuring a modular approach, it provides flexibility and allows functionalities that are easy to manage and to communicate. The model is parameterized and calibrated to simulate the 2010 dengue epidemic in Cebu City, Philippines. This works fairly well and also provides insights into the spreading process of dengue. It reveals that the changing mosquito population during rainy season has a great impact on the epidemic. It suggests how further research on that matter using models and extended biological studies might lead to a better understanding of the dengue spreading process, and eventually to more effective disease control.

MMT—An e-learning system based on computer numeric system for teaching mathematics and modelling

Abstract This paper introduces a tool enabling e-learning of modelling and simulation in a user-friendly and unique way – the MMT system. MMT stands for Mathematics, Modelling and Tools. One of the things taught with the help of the MMT system is lectures of basic mathematics, where students can experiment with MMT examples concerning Analysis and Linear Algebra to strengthen their understanding of the current subject of the lecture. The most important use of the MMT server lies in the support of teaching modelling and simulation. By varying the input parameters of models on the MMT server students can find out in which way they affect the simulation. To enable profound understanding of the models, all source codes are offered to be downloaded from the MMT system. The paper starts with a simple example to become acquainted with the MMT environment and understand the interaction of the MMT example with the corresponding function. One of the latest achievements within the MMT system has been the successful inclusion of examples accessing several m-files and further even Simulink models. The communication between the MMT server and a Simulink model is realised in a m-file exchanging parameters and output among the model and the respective MMT example. The last part of the paper discusses the use of the MMT system in exams, which is realised by the e-learning platform TUWEL. Via this tool students are asked to find out specific data coordinates or input values for a given problem on the MMT server.

Agent-Based Simulation in Archaeology: A Characterization

Historical hypotheses are usually very vaguely worded concepts trying to satisfy mankind’s curiosity about its own planet’s past. Although time can never be turned back again in order to make them a proven fact, some of these hypotheses are scientifically rather doubted and some are not as they are confirmed by historical findings. If findings are missing, arguments for the scientific credibility of hypotheses are usually very sparse. One very modern way to at least have the possibility to falsify wrong theses is computer modelling and simulation. Due to exponentially increasing performance of computers, nowadays more and more complex models can be simulated in shorter time with less efforts. Thus so called agent-based models requiring lots of memory and fast computation, are getting more and more popular also among archaeologists. The following chapter explains the basics of agent-based modelling and gives examples showing their scientific value.

Agent-Based Derivation of the SIR-Differential Equations

Due to exponentially increasing computational resources, individual-based models are getting more and more popular among epidemiologists. Inspired by SIR (Susceptible-Infected-Recovered) epidemics very complex and flexible models for diseases and vaccine strategies can be created accepting the risk, that maybe unexplained and unpredictable chaotic group-behavior could distort the results. Preventive theoretical analysis of these microscopic models is still very difficult. Based on the idea of diffusion approximation a technique is presented, how the mean value of a simple predefined agent-based SIR model can be calculated to asymptotically satisfy the classic SIR differential equations by Kermack and McKendrick. This technique can be generalized to contribute to the analysis of agent-based models and can help developing hybrid models.

Calibration Strategies for Agent-based Simulation Models with Variability

During the development of an agent-based simulation model, the model often has to be calibrated, which means adjusting the parameters such that a reference system can be reproduced. A major problem in calibrating an agent-based simulation model is the variability of the results, due to random choices made by the agents. To reduce the variability, the numbers of agents has to be increased, which in return increases the computation time of the simulation. An attempted solution to this problem consists of increasing the numbers of agents gradually. This approach is tested with two different calibration algorithm: simulated annealing and evolutionary algorithm. Different updating schedules are applied on a test model and examined in terms of their running time and their performance. It is shown that a evolutionary algorithm with an increasing agent count manages to produce similar results as a standard calibration using only half the computation time. To conclude, the best performing calibration process is used to calibrate an existing agent-based model simulating a well known past influenza epidemic.

Comparison of a microscopic and a macroscopic age-dependent SIR model

ABSTRACT In this work, we compare two structurally different modelling approaches for the simulation of an age-dependent SIR (susceptible, infected, recovered)-type epidemic spread: a microscopic agent-based model and a macroscopic integro-partial differential equation model. Doing so, we put a newly derived mean-field theorem for mixed state-spaces (continuous and discrete) to the test, analytically proving the asymptotic equivalence of the results of both simulations on the aggregate level. Afterwards, both models are executed and compared for abstract scenarios to affirm the derived equivalence. As both models are hereby proven to deliver (asymptotically) the same results, they can be used to supplement each other in terms of structural knowledge of the model, identification and determination of parameters and their values, as well as finally verification and validation.

Agent-based Modelling and Simulation for Population Dynamics under Agricultural Constraints in Prehistoric Hallstatt: Hints for a Second Settlement

This contribution is an outcome of a project cooperation between the Museum of Natural History Vienna and the Vienna University of Technology. The museum investigates since many years the prehistoric salt mines in Hallstatt, Austria, by classical archaeological methods, by experimental archaeology, and by modelling and simulation, which partly ca be seen as virtual experimental archaeology. This contribution continues investigations on modelling agricultural constraints for population size in prehistoric Hallstatt, presented in a previous conference publication. As modelling and simulation approach agent-based simulation is used, as well for the mining process, and for the supply including food production, and for the environment. First, the supply for the mining process is studied. The main focus is on the food production and its time consumption which is needed to feed all people working and living in prehistoric Hallstatt. This time consumption consists at one hand of the actual time used for seeding, mowing and harvesting and on the other hand more importantly of the time used for traveling to the fields and harvesting the goods. To simulate the traveling time an A* algorithm is used, also for the traveling time needed for the miners to get to the mine. Also the supply process of felling and transporting trees to the mine as well as chipping the wood to produce wood chips for lighting purposes is part of the simulation. Experiments with the model try to localize suitable areas for the prehistoric Hallstatt village with interesting outcome: the simulation ‘suggests’ a subdivision of the population into a village near the mine and another village at the location of today’s Hallstatt. Introduction Hallstatt is famous for its prehistoric salt mine which is of great interest for archaeologists. The special interest comes along with very well conserved finds which results of the great conserving effect of salt and the collapse of the salt mine in the 13 century B.C. Some of these finds are very special tools and it is hard to understand in which way they were used. Not at last to get a better understanding of the way these tools were used a cooperation between the Museum of Natural History Vienna and the Vienna University of Technology was formed and this work is part of it. For instance a bronze pick which was investigated with the help of simulation in another project [1]. This work mainly focuses on the food production of the population of Hallstatt. It continues previous work on modelling agricultural constraints for population size in prehistoric Hallstatt, which studies how many people could have lived in Hallstatt if it is assumed that all food was produced locally [2]. The fields considered in this preliminary work are the same as used in this work. A result of this work is that 72 persons could have been fed of the food provided by these fields. This number of persons is used in the following as the population size. The population size is an essential parameter for this work because it directly influences the time needed to work on the fields. The model which is used for this investigation is an agent-based one [3] and is implemented in Anylogic [4]. Simulation Notes Europe SNE 26(1), 2016, 41 46 DOI: 10.11128/sne.26.tn.10327 Received: November 20, 2015; Revised: March 3, 2016; Accepted: March 10, 2016; Tanzler et al. Agent-based simulation about settlements in prehistoric Hallstatt 42 SNE 26(1) – 3/2016 TN

Mean-field based comparison of two age-dependent sir models

In this work we compare two structurally different modeling approaches for the simulation of an age-dependent SIR (susceptible, infected, recovered) type epidemic spread: a microscopic agent-based model and a macroscopic integro-partial differential equation model. Doing so we put a newly derived Mean-Field Theorem for mixed state-spaces (continuous and discrete) to the test. Afterwards both models are executed and compared for two abstract scenarios to confirm the derived asymptotic equivalence.

Different Methods analysing Convection-Diffusion

Many countries in this world have lack of drinking water. Austria has advantage of drinking water coming from the mountains. This article contains a study focusing on mathematical modelling using different methods for the analysis of groundwater pollution. The distribution of pollution follows the convection-diffusion equation. Therefore different methods ranging from analytical and numerical to alternative approaches dealing with random walk are compared. The analysis of the approaches is mostly done for one and two dimensional case. Introduction In order to analysis the po llution distribution in water of sim ilar circumstances the m athematical equation describing t his be haviour i s a c onvection-diffusion equation. This equation can not only be used to analysis the be haviour of pollution. Also in biology, chem istry and ot her fiel ds of study t his e quation i s im portant. Regarding biology the equation can be use d to predict the development of fur pattern for cats. In chemistry the mixture of different substances follows this equation. In the field of physical modelling and simulation this equation is often c alled heat equation bec ause it describe s the distribution of heat em anating from a source. De spite disci plines in nat ural sciences also the fi nance market uses this equation t o foresee the behaviour of buyers of st ocks. In general the convectiondiffusion equation looks as follows: (1) Equation (1) is a partial differential equation of second or der a nd c ontains tw o dif ferent variables which can be ti me-dependent, position-dependent or simply constant. In t he following we assume that all the variables are constant. The first term of this equation describes a re gular distribution in every di rection. It is similar to spreading of waves after throwi ng in a little stone into water. The variable in th e secon d term of (1) symbolises the velocity field of oriente d movement. Assuming for example a river with a ce rtain flux the n the distribution would be influence by the velocity of the flux. This information will be transformed into t he equation using the variable . To sum it up, t he convection-diffusion equation contains one part de scribing the chaotic movement in all dir ections and an orie nted distribution depending on the circumstances. In the following a fl ux only in xdirection is assumed. This pr oblem description wi ll be a nalysed usi ng three different a pproaches applied in one and two dimensions. 1 Analytical Solution In this case, due to the used initial and boundary conditions, an anal ytical solutio n can be given. The initial condition describes a pollutio n sources which releases all the pollution at ti me without inj ecting any further pollution. B oth so lutions, oneand twodimensional, are used to validate the different methods. One-dimensional. Using the regarded equation is given as follows

An E-Learning Course of Modelling for Control Design Purposes

Abstract In the paper the main features of MMT - system are presented, for which the experimenting environment was developed, which mimic the operation of real pilot plant, consisting of three coupled tanks. Exercises lead the student from very simple and easy to understand problem to more complicated multivariable process. For evaluation purposes also some measurement data ara available.