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Sample records for agent-based tumor model

  1. Simulation of avascular tumor growth by agent-based game model involving phenotype-phenotype interactions.

    Science.gov (United States)

    Chen, Yong; Wang, Hengtong; Zhang, Jiangang; Chen, Ke; Li, Yumin

    2015-01-01

    All tumors, both benign and metastatic, undergo an avascular growth stage with nutrients supplied by the surrounding tissue. This avascular growth process is much easier to carry out in more qualitative and quantitative experiments starting from tumor spheroids in vitro with reliable reproducibility. Essentially, this tumor progression would be described as a sequence of phenotypes. Using agent-based simulation in a two-dimensional spatial lattice, we constructed a composite growth model in which the phenotypic behavior of tumor cells depends on not only the local nutrient concentration and cell count but also the game among cells. Our simulation results demonstrated that in silico tumors are qualitatively similar to those observed in tumor spheroid experiments. We also found that the payoffs in the game between two living cell phenotypes can influence the growth velocity and surface roughness of tumors at the same time. Finally, this current model is flexible and can be easily extended to discuss other situations, such as environmental heterogeneity and mutation. PMID:26648395

  2. Developing a multiscale, multi-resolution agent-based brain tumor model by graphics processing units

    Directory of Open Access Journals (Sweden)

    Zhang Le

    2011-12-01

    Full Text Available Abstract Multiscale agent-based modeling (MABM has been widely used to simulate Glioblastoma Multiforme (GBM and its progression. At the intracellular level, the MABM approach employs a system of ordinary differential equations to describe quantitatively specific intracellular molecular pathways that determine phenotypic switches among cells (e.g. from migration to proliferation and vice versa. At the intercellular level, MABM describes cell-cell interactions by a discrete module. At the tissue level, partial differential equations are employed to model the diffusion of chemoattractants, which are the input factors of the intracellular molecular pathway. Moreover, multiscale analysis makes it possible to explore the molecules that play important roles in determining the cellular phenotypic switches that in turn drive the whole GBM expansion. However, owing to limited computational resources, MABM is currently a theoretical biological model that uses relatively coarse grids to simulate a few cancer cells in a small slice of brain cancer tissue. In order to improve this theoretical model to simulate and predict actual GBM cancer progression in real time, a graphics processing unit (GPU-based parallel computing algorithm was developed and combined with the multi-resolution design to speed up the MABM. The simulated results demonstrated that the GPU-based, multi-resolution and multiscale approach can accelerate the previous MABM around 30-fold with relatively fine grids in a large extracellular matrix. Therefore, the new model has great potential for simulating and predicting real-time GBM progression, if real experimental data are incorporated.

  3. An Agent Based Classification Model

    CERN Document Server

    Gu, Feng; Greensmith, Julie

    2009-01-01

    The major function of this model is to access the UCI Wisconsin Breast Can- cer data-set[1] and classify the data items into two categories, which are normal and anomalous. This kind of classifi cation can be referred as anomaly detection, which discriminates anomalous behaviour from normal behaviour in computer systems. One popular solution for anomaly detection is Artifi cial Immune Sys- tems (AIS). AIS are adaptive systems inspired by theoretical immunology and observed immune functions, principles and models which are applied to prob- lem solving. The Dendritic Cell Algorithm (DCA)[2] is an AIS algorithm that is developed specifi cally for anomaly detection. It has been successfully applied to intrusion detection in computer security. It is believed that agent-based mod- elling is an ideal approach for implementing AIS, as intelligent agents could be the perfect representations of immune entities in AIS. This model evaluates the feasibility of re-implementing the DCA in an agent-based simulation environ- ...

  4. Agent-based modeling and network dynamics

    CERN Document Server

    Namatame, Akira

    2016-01-01

    The book integrates agent-based modeling and network science. It is divided into three parts, namely, foundations, primary dynamics on and of social networks, and applications. The book begins with the network origin of agent-based models, known as cellular automata, and introduce a number of classic models, such as Schelling’s segregation model and Axelrod’s spatial game. The essence of the foundation part is the network-based agent-based models in which agents follow network-based decision rules. Under the influence of the substantial progress in network science in late 1990s, these models have been extended from using lattices into using small-world networks, scale-free networks, etc. The book also shows that the modern network science mainly driven by game-theorists and sociophysicists has inspired agent-based social scientists to develop alternative formation algorithms, known as agent-based social networks. The book reviews a number of pioneering and representative models in this family. Upon the gi...

  5. Agent Based Multiviews Requirements Model

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Based on the current researches of viewpoints oriented requirements engineering and intelligent agent, we present the concept of viewpoint agent and its abstract model based on a meta-language for multiviews requirements engineering. It provided a basis for consistency checking and integration of different viewpoint requirements, at the same time, these checking and integration works can automatically realized in virtue of intelligent agent's autonomy, proactiveness and social ability. Finally, we introduce the practical application of the model by the case study of data flow diagram.

  6. An Agent Based Classification Model

    OpenAIRE

    Gu, Feng; Aickelin, Uwe; Greensmith, Julie

    2009-01-01

    The major function of this model is to access the UCI Wisconsin Breast Can- cer data-set[1] and classify the data items into two categories, which are normal and anomalous. This kind of classifi cation can be referred as anomaly detection, which discriminates anomalous behaviour from normal behaviour in computer systems. One popular solution for anomaly detection is Artifi cial Immune Sys- tems (AIS). AIS are adaptive systems inspired by theoretical immunology and observed immune functions, p...

  7. Agent Based Modelling for Social Simulation

    NARCIS (Netherlands)

    Smit, S.K.; Ubink, E.M.; Vecht, B. van der; Langley, D.J.

    2013-01-01

    This document is the result of an exploratory project looking into the status of, and opportunities for Agent Based Modelling (ABM) at TNO. The project focussed on ABM applications containing social interactions and human factors, which we termed ABM for social simulation (ABM4SS). During the course

  8. Agent-Based Modeling in Systems Pharmacology.

    Science.gov (United States)

    Cosgrove, J; Butler, J; Alden, K; Read, M; Kumar, V; Cucurull-Sanchez, L; Timmis, J; Coles, M

    2015-11-01

    Modeling and simulation (M&S) techniques provide a platform for knowledge integration and hypothesis testing to gain insights into biological systems that would not be possible a priori. Agent-based modeling (ABM) is an M&S technique that focuses on describing individual components rather than homogenous populations. This tutorial introduces ABM to systems pharmacologists, using relevant case studies to highlight how ABM-specific strengths have yielded success in the area of preclinical mechanistic modeling. PMID:26783498

  9. Agent-based Models of Financial Markets

    OpenAIRE

    Samanidou, E.; E. Zschischang; Stauffer, D.; Lux, T.

    2007-01-01

    This review deals with several microscopic (``agent-based'') models of financial markets which have been studied by economists and physicists over the last decade: Kim-Markowitz, Levy-Levy-Solomon, Cont-Bouchaud, Solomon-Weisbuch, Lux-Marchesi, Donangelo-Sneppen and Solomon-Levy-Huang. After an overview of simulation approaches in financial economics, we first give a summary of the Donangelo-Sneppen model of monetary exchange and compare it with related models in economics literature. Our sel...

  10. Multiscale agent-based consumer market modeling.

    Energy Technology Data Exchange (ETDEWEB)

    North, M. J.; Macal, C. M.; St. Aubin, J.; Thimmapuram, P.; Bragen, M.; Hahn, J.; Karr, J.; Brigham, N.; Lacy, M. E.; Hampton, D.; Decision and Information Sciences; Procter & Gamble Co.

    2010-05-01

    Consumer markets have been studied in great depth, and many techniques have been used to represent them. These have included regression-based models, logit models, and theoretical market-level models, such as the NBD-Dirichlet approach. Although many important contributions and insights have resulted from studies that relied on these models, there is still a need for a model that could more holistically represent the interdependencies of the decisions made by consumers, retailers, and manufacturers. When the need is for a model that could be used repeatedly over time to support decisions in an industrial setting, it is particularly critical. Although some existing methods can, in principle, represent such complex interdependencies, their capabilities might be outstripped if they had to be used for industrial applications, because of the details this type of modeling requires. However, a complementary method - agent-based modeling - shows promise for addressing these issues. Agent-based models use business-driven rules for individuals (e.g., individual consumer rules for buying items, individual retailer rules for stocking items, or individual firm rules for advertizing items) to determine holistic, system-level outcomes (e.g., to determine if brand X's market share is increasing). We applied agent-based modeling to develop a multi-scale consumer market model. We then conducted calibration, verification, and validation tests of this model. The model was successfully applied by Procter & Gamble to several challenging business problems. In these situations, it directly influenced managerial decision making and produced substantial cost savings.

  11. Agent Based Modeling in Public Administration

    Directory of Open Access Journals (Sweden)

    Osman SEYHAN

    2013-06-01

    Full Text Available This study aims to explore the role of agent based modeling (ABM as a simulation method in analyzing and formulating the policy making processes and modern public management that is under the pressure of information age and socio-politic demands of open societies. ABM is a simulative research method to understand complex adaptive systems (cas from the perspective of its constituent entities. In this study, by employing agent based computing and Netlogo language, twocase studies about organizational design and organizational riskanalyses have been examined. Results revealed that ABM is anefficient platform determining the optimum results from various scenarios in order to understand structures and processes about policy making in both organizational design and risk management. In the future, more researches are needed about understanding role of ABM on understanding and making decision on future of cas especially in conjunction with developments in computer technologies.

  12. Agent-based modeling and simulation

    CERN Document Server

    Taylor, Simon

    2014-01-01

    Operational Research (OR) deals with the use of advanced analytical methods to support better decision-making. It is multidisciplinary with strong links to management science, decision science, computer science and many application areas such as engineering, manufacturing, commerce and healthcare. In the study of emergent behaviour in complex adaptive systems, Agent-based Modelling & Simulation (ABMS) is being used in many different domains such as healthcare, energy, evacuation, commerce, manufacturing and defense. This collection of articles presents a convenient introduction to ABMS with pa

  13. Econophysics of agent-based models

    CERN Document Server

    Aoyama, Hideaki; Chakrabarti, Bikas; Chakraborti, Anirban; Ghosh, Asim

    2014-01-01

    The primary goal of this book is to present the research findings and conclusions of physicists, economists, mathematicians and financial engineers working in the field of "Econophysics" who have undertaken agent-based modelling, comparison with empirical studies and related investigations. Most standard economic models assume the existence of the representative agent, who is “perfectly rational” and applies the utility maximization principle when taking action. One reason for this is the desire to keep models mathematically tractable: no tools are available to economists for solving non-linear models of heterogeneous adaptive agents without explicit optimization. In contrast, multi-agent models, which originated from statistical physics considerations, allow us to go beyond the prototype theories of traditional economics involving the representative agent. This book is based on the Econophys-Kolkata VII Workshop, at which many such modelling efforts were presented. In the book, leading researchers in the...

  14. Spatial interactions in agent-based modeling

    CERN Document Server

    Ausloos, Marcel; Merlone, Ugo

    2014-01-01

    Agent Based Modeling (ABM) has become a widespread approach to model complex interactions. In this chapter after briefly summarizing some features of ABM the different approaches in modeling spatial interactions are discussed. It is stressed that agents can interact either indirectly through a shared environment and/or directly with each other. In such an approach, higher-order variables such as commodity prices, population dynamics or even institutions, are not exogenously specified but instead are seen as the results of interactions. It is highlighted in the chapter that the understanding of patterns emerging from such spatial interaction between agents is a key problem as much as their description through analytical or simulation means. The chapter reviews different approaches for modeling agents' behavior, taking into account either explicit spatial (lattice based) structures or networks. Some emphasis is placed on recent ABM as applied to the description of the dynamics of the geographical distribution o...

  15. An Agent-Based Monetary Production Simulation Model

    DEFF Research Database (Denmark)

    Bruun, Charlotte

    2006-01-01

    An Agent-Based Simulation Model Programmed in Objective Borland Pascal. Program and source code is downloadable......An Agent-Based Simulation Model Programmed in Objective Borland Pascal. Program and source code is downloadable...

  16. Agent Based Modeling as an Educational Tool

    Science.gov (United States)

    Fuller, J. H.; Johnson, R.; Castillo, V.

    2012-12-01

    Motivation is a key element in high school education. One way to improve motivation and provide content, while helping address critical thinking and problem solving skills, is to have students build and study agent based models in the classroom. This activity visually connects concepts with their applied mathematical representation. "Engaging students in constructing models may provide a bridge between frequently disconnected conceptual and mathematical forms of knowledge." (Levy and Wilensky, 2011) We wanted to discover the feasibility of implementing a model based curriculum in the classroom given current and anticipated core and content standards.; Simulation using California GIS data ; Simulation of high school student lunch popularity using aerial photograph on top of terrain value map.

  17. Agent based modeling in tactical wargaming

    Science.gov (United States)

    James, Alex; Hanratty, Timothy P.; Tuttle, Daniel C.; Coles, John B.

    2016-05-01

    Army staffs at division, brigade, and battalion levels often plan for contingency operations. As such, analysts consider the impact and potential consequences of actions taken. The Army Military Decision-Making Process (MDMP) dictates identification and evaluation of possible enemy courses of action; however, non-state actors often do not exhibit the same level and consistency of planned actions that the MDMP was originally designed to anticipate. The fourth MDMP step is a particular challenge, wargaming courses of action within the context of complex social-cultural behaviors. Agent-based Modeling (ABM) and its resulting emergent behavior is a potential solution to model terrain in terms of the human domain and improve the results and rigor of the traditional wargaming process.

  18. Agent Based Model of Livestock Movements

    Science.gov (United States)

    Miron, D. J.; Emelyanova, I. V.; Donald, G. E.; Garner, G. M.

    The modelling of livestock movements within Australia is of national importance for the purposes of the management and control of exotic disease spread, infrastructure development and the economic forecasting of livestock markets. In this paper an agent based model for the forecasting of livestock movements is presented. This models livestock movements from farm to farm through a saleyard. The decision of farmers to sell or buy cattle is often complex and involves many factors such as climate forecast, commodity prices, the type of farm enterprise, the number of animals available and associated off-shore effects. In this model the farm agent's intelligence is implemented using a fuzzy decision tree that utilises two of these factors. These two factors are the livestock price fetched at the last sale and the number of stock on the farm. On each iteration of the model farms choose either to buy, sell or abstain from the market thus creating an artificial supply and demand. The buyers and sellers then congregate at the saleyard where livestock are auctioned using a second price sealed bid. The price time series output by the model exhibits properties similar to those found in real livestock markets.

  19. Validating agent based models through virtual worlds.

    Energy Technology Data Exchange (ETDEWEB)

    Lakkaraju, Kiran; Whetzel, Jonathan H.; Lee, Jina; Bier, Asmeret Brooke; Cardona-Rivera, Rogelio E.; Bernstein, Jeremy Ray Rhythm

    2014-01-01

    As the US continues its vigilance against distributed, embedded threats, understanding the political and social structure of these groups becomes paramount for predicting and dis- rupting their attacks. Agent-based models (ABMs) serve as a powerful tool to study these groups. While the popularity of social network tools (e.g., Facebook, Twitter) has provided extensive communication data, there is a lack of ne-grained behavioral data with which to inform and validate existing ABMs. Virtual worlds, in particular massively multiplayer online games (MMOG), where large numbers of people interact within a complex environ- ment for long periods of time provide an alternative source of data. These environments provide a rich social environment where players engage in a variety of activities observed between real-world groups: collaborating and/or competing with other groups, conducting battles for scarce resources, and trading in a market economy. Strategies employed by player groups surprisingly re ect those seen in present-day con icts, where players use diplomacy or espionage as their means for accomplishing their goals. In this project, we propose to address the need for ne-grained behavioral data by acquiring and analyzing game data a commercial MMOG, referred to within this report as Game X. The goals of this research were: (1) devising toolsets for analyzing virtual world data to better inform the rules that govern a social ABM and (2) exploring how virtual worlds could serve as a source of data to validate ABMs established for analogous real-world phenomena. During this research, we studied certain patterns of group behavior to compliment social modeling e orts where a signi cant lack of detailed examples of observed phenomena exists. This report outlines our work examining group behaviors that underly what we have termed the Expression-To-Action (E2A) problem: determining the changes in social contact that lead individuals/groups to engage in a particular behavior

  20. A generic testing framework for agent-based simulation models

    OpenAIRE

    Gürcan, Önder; Dikenelli, Oguz; Bernon, Carole

    2013-01-01

    International audience Agent-based modelling and simulation (ABMS) had an increasing attention during the last decade. However, the weak validation and verification of agent-based simulation models makes ABMS hard to trust. There is no comprehensive tool set for verification and validation of agent-based simulation models, which demonstrates that inaccuracies exist and/or reveals the existing errors in the model. Moreover, on the practical side, many ABMS frameworks are in use. In this sen...

  1. Agent Based Modelling and Simulation of Social Processes

    OpenAIRE

    Armano Srbljinovic; Ognjen Skunca

    2003-01-01

    The paper provides an introduction to agent-based modelling and simulation of social processes. Reader is introduced to the worldview underlying agent-based models, some basic terminology, basic properties of agent-based models, as well as to what one can and what cannot expect from such models, particularly when they are applied to social-scientific investigation. Special attention is given to the issues of validation. Classification-ACM-1998: J.4 [Computer Applications]; Social and behavior...

  2. Agent-based models of financial markets

    Science.gov (United States)

    Samanidou, E.; Zschischang, E.; Stauffer, D.; Lux, T.

    2007-03-01

    This review deals with several microscopic ('agent-based') models of financial markets which have been studied by economists and physicists over the last decade: Kim-Markowitz, Levy-Levy-Solomon, Cont-Bouchaud, Solomon-Weisbuch, Lux-Marchesi, Donangelo-Sneppen and Solomon-Levy-Huang. After an overview of simulation approaches in financial economics, we first give a summary of the Donangelo-Sneppen model of monetary exchange and compare it with related models in economics literature. Our selective review then outlines the main ingredients of some influential early models of multi-agent dynamics in financial markets (Kim-Markowitz, Levy-Levy-Solomon). As will be seen, these contributions draw their inspiration from the complex appearance of investors' interactions in real-life markets. Their main aim is to reproduce (and, thereby, provide possible explanations) for the spectacular bubbles and crashes seen in certain historical episodes, but they lack (like almost all the work before 1998 or so) a perspective in terms of the universal statistical features of financial time series. In fact, awareness of a set of such regularities (power-law tails of the distribution of returns, temporal scaling of volatility) only gradually appeared over the nineties. With the more precise description of the formerly relatively vague characteristics (e.g. moving from the notion of fat tails to the more concrete one of a power law with index around three), it became clear that financial market dynamics give rise to some kind of universal scaling law. Showing similarities with scaling laws for other systems with many interacting sub-units, an exploration of financial markets as multi-agent systems appeared to be a natural consequence. This topic has been pursued by quite a number of contributions appearing in both the physics and economics literature since the late nineties. From the wealth of different flavours of multi-agent models that have appeared up to now, we discuss the Cont

  3. Agent-based models of financial markets

    Energy Technology Data Exchange (ETDEWEB)

    Samanidou, E [Department of Economics, University of Kiel, Olshausenstrasse 40, D-24118 Kiel (Germany); Zschischang, E [HSH Nord Bank, Portfolio Mngmt. and Inv., Martensdamm 6, D-24103 Kiel (Germany); Stauffer, D [Institute for Theoretical Physics, Cologne University, D-50923 Koeln (Germany); Lux, T [Department of Economics, University of Kiel, Olshausenstrasse 40, D-24118 Kiel (Germany)

    2007-03-15

    This review deals with several microscopic ('agent-based') models of financial markets which have been studied by economists and physicists over the last decade: Kim-Markowitz, Levy-Levy-Solomon, Cont-Bouchaud, Solomon-Weisbuch, Lux-Marchesi, Donangelo-Sneppen and Solomon-Levy-Huang. After an overview of simulation approaches in financial economics, we first give a summary of the Donangelo-Sneppen model of monetary exchange and compare it with related models in economics literature. Our selective review then outlines the main ingredients of some influential early models of multi-agent dynamics in financial markets (Kim-Markowitz, Levy-Levy-Solomon). As will be seen, these contributions draw their inspiration from the complex appearance of investors' interactions in real-life markets. Their main aim is to reproduce (and, thereby, provide possible explanations) for the spectacular bubbles and crashes seen in certain historical episodes, but they lack (like almost all the work before 1998 or so) a perspective in terms of the universal statistical features of financial time series. In fact, awareness of a set of such regularities (power-law tails of the distribution of returns, temporal scaling of volatility) only gradually appeared over the nineties. With the more precise description of the formerly relatively vague characteristics (e.g. moving from the notion of fat tails to the more concrete one of a power law with index around three), it became clear that financial market dynamics give rise to some kind of universal scaling law. Showing similarities with scaling laws for other systems with many interacting sub-units, an exploration of financial markets as multi-agent systems appeared to be a natural consequence. This topic has been pursued by quite a number of contributions appearing in both the physics and economics literature since the late nineties. From the wealth of different flavours of multi-agent models that have appeared up to now, we

  4. The Gap of Current Agent Based Simulation Modeling Practices and Feasibility of a Generic Agent Based Simulation Model

    OpenAIRE

    Yim Ling Loo; Alicia Y.C. Tang; Azhana Ahmad

    2015-01-01

    Agent-based modeling had been revolving to be established approach in modeling simulation systems which are used to understand and predict certain real-life scenarios in specific domains. Past researches which are domain-specific caused repetitive building of new models from scratch and restrict replication and reuse because of limitation of models’ description. This paper presents a review of gaps between domain-specific agent-based simulation modeling and the recent practices of agent-based...

  5. An Active Learning Exercise for Introducing Agent-Based Modeling

    Science.gov (United States)

    Pinder, Jonathan P.

    2013-01-01

    Recent developments in agent-based modeling as a method of systems analysis and optimization indicate that students in business analytics need an introduction to the terminology, concepts, and framework of agent-based modeling. This article presents an active learning exercise for MBA students in business analytics that demonstrates agent-based…

  6. Agent-Based Modeling of Growth Processes

    Science.gov (United States)

    Abraham, Ralph

    2014-01-01

    Growth processes abound in nature, and are frequently the target of modeling exercises in the sciences. In this article we illustrate an agent-based approach to modeling, in the case of a single example from the social sciences: bullying.

  7. Agent-based Models for Economic Policy Design

    OpenAIRE

    Dawid, Herbert; Neugart, Michael

    2010-01-01

    Agent-based simulation models are used by an increasing number of scholars as a tool for providing evaluations of economic policy measures and policy recommendations in complex environments. On the basis of recent work in this area we discuss the advantages of agent-based modeling for economic policy design and identify further needs to be addressed for strengthening this methodological approach as a basis for sound policy advice.

  8. Social scientists, qualitative data, and agent-based modeling

    OpenAIRE

    Seidl, Roman

    2014-01-01

    Empirical data obtained with social science methods can be useful for informing agent-based models, for instance, to fix the profile of heterogeneous agents or to specify behavioral rules. For the latter in particular, qualitative methods that investigate the details of individual decision processes are an option. In this paper, I highlight the challenges for social scientists who investigate social/psychological phenomena but at the same time have to consider the properties of agent-based si...

  9. Agent Based Reasoning in Multilevel Flow Modeling

    DEFF Research Database (Denmark)

    Lind, Morten; Zhang, Xinxin

    2012-01-01

    Multilevel Flow Modeling (MFM) is a modeling method used for modeling complex industrial plant. Currently, MFM is supported with a standalone software tool called MFM Workbench, which is equipped with causal-relation analysis and other functionalities. The aim of this paper is to offer a new design...

  10. Agent-based modelling of socio-technical systems

    CERN Document Server

    van Dam, Koen H; Lukszo, Zofia

    2012-01-01

    Here is a practical introduction to agent-based modelling of socio-technical systems, based on methodology developed at TU Delft, which has been deployed in a number of case studies. Offers theory, methods and practical steps for creating real-world models.

  11. On infrastructure network design with agent-based modelling

    NARCIS (Netherlands)

    Chappin, E.J.L.; Heijnen, P.W.

    2014-01-01

    We have developed an agent-based model to optimize green-field network design in an industrial area. We aim to capture some of the deep uncertainties surrounding infrastructure design by modelling it developing specific ant colony optimizations. Hence, we propose a variety of extensions to our exist

  12. Structuring Qualitative Data for Agent-Based Modelling

    NARCIS (Netherlands)

    Ghorbani, Amineh; Dijkema, Gerard P.J.; Schrauwen, Noortje

    2015-01-01

    Using ethnography to build agent-based models may result in more empirically grounded simulations. Our study on innovation practice and culture in the Westland horticulture sector served to explore what information and data from ethnographic analysis could be used in models and how. MAIA, a framewor

  13. Cognitive Modeling for Agent-Based Simulation of Child Maltreatment

    Science.gov (United States)

    Hu, Xiaolin; Puddy, Richard

    This paper extends previous work to develop cognitive modeling for agent-based simulation of child maltreatment (CM). The developed model is inspired from parental efficacy, parenting stress, and the theory of planned behavior. It provides an explanatory, process-oriented model of CM and incorporates causality relationship and feedback loops from different factors in the social ecology in order for simulating the dynamics of CM. We describe the model and present simulation results to demonstrate the features of this model.

  14. Agent-Based Modeling: A Powerful Tool for Tourism Researchers

    NARCIS (Netherlands)

    Nicholls, Sarah; Amelung, B.; Student, Jillian

    2016-01-01

    Agent-based modeling (ABM) is a way of representing complex systems of autonomous agents or actors, and of simulating the multiple potential outcomes of these agents’ behaviors and interactions in the form of a range of alternatives or futures. Despite the complexity of the tourism system, and the p

  15. Tutorial on agent-based modeling and simulation.

    Energy Technology Data Exchange (ETDEWEB)

    Macal, C. M.; North, M. J.; Decision and Information Sciences

    2005-01-01

    Agent-based modeling and simulation (ABMS) is a new approach to modeling systems comprised of autonomous, interacting agents. ABMS promises to have far-reaching effects on the way that businesses use computers to support decision-making and researchers use electronic laboratories to support their research. Some have gone so far as to contend that ABMS is a third way of doing science besides deductive and inductive reasoning. Computational advances have made possible a growing number of agent-based applications in a variety of fields. Applications range from modeling agent behavior in the stock market and supply chains, to predicting the spread of epidemics and the threat of bio-warfare, from modeling consumer behavior to understanding the fall of ancient civilizations, to name a few. This tutorial describes the theoretical and practical foundations of ABMS, identifies toolkits and methods for developing ABMS models, and provides some thoughts on the relationship between ABMS and traditional modeling techniques.

  16. Agent-based Model Construction in Financial Economic System

    OpenAIRE

    Hokky Situngkir; Yohanes Surya

    2004-01-01

    The paper gives picture of enrichment to economic and financial system analysis using agent-based models as a form of advanced study for financial economic data post-statistical-data analysis and micro- simulation analysis. Theoretical exploration is carried out by using comparisons of some usual financial economy system models frequently and popularly used in econophysics and computational finance. Primitive model, which consists of agent microsimulation with fundamentalist strategy, chartis...

  17. An Agent-Based Dialogical Model with Fuzzy Attitudes

    OpenAIRE

    Piter Dykstra; Wander Jager; Corinna Elsenbroich; Rineke Verbrugge; Gerard Renardel de Lavalette

    2015-01-01

    This paper presents an extension to an agent-based model of opinion dynamics built on dialogical logic DIAL. The extended model tackles a pervasive problem in argumentation logics: the difference between linguistic and logical inconsistency. Using fuzzy logic, the linear ordering of opinions, used in DIAL, is replaced by a set of partial orderings leading to a new, nonstandard notion of consistency as convexity of sets of statements. DIAL allows the modelling of the interplay of social struct...

  18. Container Terminal Operations Modeling through Multi agent based Simulation

    OpenAIRE

    Ayub, Yasir; Faruki, Usman

    2009-01-01

    This thesis aims to propose a multi-agent based hierarchical model for the operations of container terminals. We have divided our model into four key agents that are involved in each sub processes. The proposed agent allocation policies are recommended for different situations that may occur at a container terminal. A software prototype is developed which implements the hierarchical model. This web based application is used in order to simulate the various processes involved in the following ...

  19. Agent-based Modeling with MATSim for Hazards Evacuation Planning

    Science.gov (United States)

    Jones, J. M.; Ng, P.; Henry, K.; Peters, J.; Wood, N. J.

    2015-12-01

    Hazard evacuation planning requires robust modeling tools and techniques, such as least cost distance or agent-based modeling, to gain an understanding of a community's potential to reach safety before event (e.g. tsunami) arrival. Least cost distance modeling provides a static view of the evacuation landscape with an estimate of travel times to safety from each location in the hazard space. With this information, practitioners can assess a community's overall ability for timely evacuation. More information may be needed if evacuee congestion creates bottlenecks in the flow patterns. Dynamic movement patterns are best explored with agent-based models that simulate movement of and interaction between individual agents as evacuees through the hazard space, reacting to potential congestion areas along the evacuation route. The multi-agent transport simulation model MATSim is an agent-based modeling framework that can be applied to hazard evacuation planning. Developed jointly by universities in Switzerland and Germany, MATSim is open-source software written in Java and freely available for modification or enhancement. We successfully used MATSim to illustrate tsunami evacuation challenges in two island communities in California, USA, that are impacted by limited escape routes. However, working with MATSim's data preparation, simulation, and visualization modules in an integrated development environment requires a significant investment of time to develop the software expertise to link the modules and run a simulation. To facilitate our evacuation research, we packaged the MATSim modules into a single application tailored to the needs of the hazards community. By exposing the modeling parameters of interest to researchers in an intuitive user interface and hiding the software complexities, we bring agent-based modeling closer to practitioners and provide access to the powerful visual and analytic information that this modeling can provide.

  20. From agent-based models to artificial economies

    OpenAIRE

    Teglio, Andrea

    2011-01-01

    The aim of this thesis is to propose and illustrate an alternative approach to economic modeling and policy design that is grounded in the innovative field of agent-based computational economics (ACE). The recent crisis pointed out the fundamental role played by macroeconomic policy design in order to preserve social welfare, and the consequent necessity of understanding the effects of coordinated policy measures on the economic system. Classic approaches to macroeconomic modeling, mainly rep...

  1. Online analysis and visualization of agent based models

    OpenAIRE

    Grignard, Arnaud; Drogoul, Alexis; Zucker, Jean-Daniel

    2013-01-01

    International audience Agent-based modeling is used to study many kind of complex systems in different fields such as biology, ecology, or sociology. Visualization of the execution of a such complex systems is crucial in the capacity to apprehend its dynamics. The ever increasing complexification of requirements asked by the modeller has highlighted the need for more powerful tools than the existing ones to represent, visualize and interact with a simulation and extract data online to disc...

  2. Agent-Based Modeling and Mapping of Manufacturing System

    Institute of Scientific and Technical Information of China (English)

    Z; Zhang

    2002-01-01

    Considering the agent-based modeling and mapping i n manufacturing system, some system models are described in this paper, which are included: Domain Based Hierarchical Structure (DBHS), Cascading Agent Structure (CAS), Proximity Relation Structure (PRS), and Bus-based Network Structure (BNS ). In DBHS, one sort of agents, called static agents, individually acts as Domai n Agents, Resources Agents, UserInterface Agents and Gateway Agents. And the oth ers, named mobile agents, are the brokers of task and ...

  3. Agent Based Model of Young Researchers in Higher Education Institutions

    OpenAIRE

    Josip Stepanic; Mirjana Pejic Bach; Josip Kasac

    2013-01-01

    Group of young researchers in higher education institutions in general perform demandable tasks with relatively high contribution to institutions’ and societies’ innovation production. In order to analyse in more details interaction among young researchers and diverse institutions in society, we aim toward developing the numerical simulation, agent-based model. This article presents foundations of the model, preliminary results of its simulation along with perspectives of its further deve...

  4. Agent-based modeling and simulation Part 3 : desktop ABMS.

    Energy Technology Data Exchange (ETDEWEB)

    Macal, C. M.; North, M. J.; Decision and Information Sciences

    2007-01-01

    Agent-based modeling and simulation (ABMS) is a new approach to modeling systems comprised of autonomous, interacting agents. ABMS promises to have far-reaching effects on the way that businesses use computers to support decision-making and researchers use electronic laboratories to support their research. Some have gone so far as to contend that ABMS 'is a third way of doing science,' in addition to traditional deductive and inductive reasoning (Axelrod 1997b). Computational advances have made possible a growing number of agent-based models across a variety of application domains. Applications range from modeling agent behavior in the stock market, supply chains, and consumer markets, to predicting the spread of epidemics, the threat of bio-warfare, and the factors responsible for the fall of ancient civilizations. This tutorial describes the theoretical and practical foundations of ABMS, identifies toolkits and methods for developing agent models, and illustrates the development of a simple agent-based model of shopper behavior using spreadsheets.

  5. Deep Learning in Agent-Based Models: A Prospectus

    OpenAIRE

    Hoog, Sander van der

    2016-01-01

    A very timely issue for economic agent-based models (ABMs) is their empirical estimation. This paper describes a line of research that could resolve the issue by using machine learning techniques, using multi-layer artificial neural networks (ANNs), or so called Deep Nets. The seminal contribution by Hinton et al. (2006) introduced a fast and efficient training algorithm called Deep Learning, and there have been major breakthroughs in machine learning ever since. Economics has not yet benefit...

  6. Modeling and simulation of complex systems a framework for efficient agent-based modeling and simulation

    CERN Document Server

    Siegfried, Robert

    2014-01-01

    Robert Siegfried presents a framework for efficient agent-based modeling and simulation of complex systems. He compares different approaches for describing structure and dynamics of agent-based models in detail. Based on this evaluation the author introduces the "General Reference Model for Agent-based Modeling and Simulation" (GRAMS). Furthermore he presents parallel and distributed simulation approaches for execution of agent-based models -from small scale to very large scale. The author shows how agent-based models may be executed by different simulation engines that utilize underlying hard

  7. Many-body methods in agent-based epidemic models

    CERN Document Server

    Nakamura, Gilberto M

    2016-01-01

    The susceptible-infected-susceptible (SIS) agent-based model is usually employed in the investigation of epidemics. The model describes a Markov process for a single communicable disease among susceptible (S) and infected (I) agents. However, the disease spreading forecasting is often restricted to numerical simulations, while analytic formulations lack both general results and perturbative approaches since they are subjected to asymmetric time generators. Here, we discuss perturbation theory, approximations and application of many-body techniques in epidemic models in the framework for squared norm of probability vector $|P(t)| ^2$, in which asymmetric time generators are replaced by their symmetric counterparts.

  8. Agent-Based Approaches for Behavioural Modelling in Military Simulations

    Directory of Open Access Journals (Sweden)

    Gaurav Chaudhary

    2015-12-01

    Full Text Available Behavioral modeling of combat entities in military simulations by creating synthetic agents in order to satisfy various battle scenarios is an important problem. The conventional modeling tools are not always sufficient to handle complex situations requiring adaptation. To deal with this Agent-Based Modeling (ABM is employed, as the agents exhibit autonomous behavior by adapting and varying their behavior during the course of the simulation whilst achieving the goals. Synthetic agents created by means of Computer Generated Force (CGF is a relatively recent approach to model behavior of combat entities for a more realistic training and effective military planning. CGFs, are also sometimes referred to as Semi- Automated Forces (SAF and enables to create high-fidelity simulations. Agents are used to control and augment the behavior of CGF entities, hence converting them into Intelligent CGF (ICGF. The intelligent agents can be modeled to exhibit cognitive abilities. For this review paper, extensive papers on stateof-the-art in agent-based modeling approaches and applications were surveyed. The paper assimilates issues involved in ABM with CGF as an important component of it. It reviews modeling aspects with respect to the interrelationship between ABM and CGF, which is required to carry out behavioral modeling. Important CGFs have been examined and a list with their significant features is given. Another issue that has been reviewed is that how the synthetic agents having different capabilities are implemented at different battle levels. Brief mention of state-of-the-art integrated cognitive architectures and a list of significant cognitive applications based on them with their features is given. At the same time, the maturity of ABM in agent-based applications has also been considered.

  9. Agent-Based Deterministic Modeling of the Bone Marrow Homeostasis.

    Science.gov (United States)

    Kurhekar, Manish; Deshpande, Umesh

    2016-01-01

    Modeling of stem cells not only describes but also predicts how a stem cell's environment can control its fate. The first stem cell populations discovered were hematopoietic stem cells (HSCs). In this paper, we present a deterministic model of bone marrow (that hosts HSCs) that is consistent with several of the qualitative biological observations. This model incorporates stem cell death (apoptosis) after a certain number of cell divisions and also demonstrates that a single HSC can potentially populate the entire bone marrow. It also demonstrates that there is a production of sufficient number of differentiated cells (RBCs, WBCs, etc.). We prove that our model of bone marrow is biologically consistent and it overcomes the biological feasibility limitations of previously reported models. The major contribution of our model is the flexibility it allows in choosing model parameters which permits several different simulations to be carried out in silico without affecting the homeostatic properties of the model. We have also performed agent-based simulation of the model of bone marrow system proposed in this paper. We have also included parameter details and the results obtained from the simulation. The program of the agent-based simulation of the proposed model is made available on a publicly accessible website. PMID:27340402

  10. On infrastructure network design with agent-based modelling

    OpenAIRE

    Chappin, E.J.L.; Heijnen, P.W.

    2014-01-01

    We have developed an agent-based model to optimize green-field network design in an industrial area. We aim to capture some of the deep uncertainties surrounding infrastructure design by modelling it developing specific ant colony optimizations. Hence, we propose a variety of extensions to our existing work, first ideas on how to realize them and three cases to explicate our ideas. One case is the design of a CO2 pipeline network in Rotterdam industrial area. First simulation results have sho...

  11. An Agent Based Model for Social Class Emergence

    Science.gov (United States)

    Yang, Xiaoxiang; Rodriguez Segura, Daniel; Lin, Fei; Mazilu, Irina

    We present an open system agent-based model to analyze the effects of education and the society-specific wealth transactions on the emergence of social classes. Building on previous studies, we use realistic functions to model how years of education affect the income level. Numerical simulations show that the fraction of an individual's total transactions that is invested rather than consumed can cause wealth gaps between different income brackets in the long run. In an attempt to incorporate the network effects, we also explore how the probability of interactions among agents depending on the spread of their income brackets affects wealth distribution.

  12. Empirical agent-based modelling challenges and solutions

    CERN Document Server

    Barreteau, Olivier

    2014-01-01

    This instructional book showcases techniques to parameterise human agents in empirical agent-based models (ABM). In doing so, it provides a timely overview of key ABM methodologies and the most innovative approaches through a variety of empirical applications.  It features cutting-edge research from leading academics and practitioners, and will provide a guide for characterising and parameterising human agents in empirical ABM.  In order to facilitate learning, this text shares the valuable experiences of other modellers in particular modelling situations. Very little has been published in the area of empirical ABM, and this contributed volume will appeal to graduate-level students and researchers studying simulation modeling in economics, sociology, ecology, and trans-disciplinary studies, such as topics related to sustainability. In a similar vein to the instruction found in a cookbook, this text provides the empirical modeller with a set of 'recipes'  ready to be implemented. Agent-based modeling (AB...

  13. Markov chain aggregation for agent-based models

    CERN Document Server

    Banisch, Sven

    2016-01-01

    This self-contained text develops a Markov chain approach that makes the rigorous analysis of a class of microscopic models that specify the dynamics of complex systems at the individual level possible. It presents a general framework of aggregation in agent-based and related computational models, one which makes use of lumpability and information theory in order to link the micro and macro levels of observation. The starting point is a microscopic Markov chain description of the dynamical process in complete correspondence with the dynamical behavior of the agent-based model (ABM), which is obtained by considering the set of all possible agent configurations as the state space of a huge Markov chain. An explicit formal representation of a resulting “micro-chain” including microscopic transition rates is derived for a class of models by using the random mapping representation of a Markov process. The type of probability distribution used to implement the stochastic part of the model, which defines the upd...

  14. An Agent-Based Modeling for Pandemic Influenza in Egypt

    CERN Document Server

    Khalil, Khaled M; Nazmy, Taymour T; Salem, Abdel-Badeeh M

    2010-01-01

    Pandemic influenza has great potential to cause large and rapid increases in deaths and serious illness. The objective of this paper is to develop an agent-based model to simulate the spread of pandemic influenza (novel H1N1) in Egypt. The proposed multi-agent model is based on the modeling of individuals' interactions in a space time context. The proposed model involves different types of parameters such as: social agent attributes, distribution of Egypt population, and patterns of agents' interactions. Analysis of modeling results leads to understanding the characteristics of the modeled pandemic, transmission patterns, and the conditions under which an outbreak might occur. In addition, the proposed model is used to measure the effectiveness of different control strategies to intervene the pandemic spread.

  15. Agent Based Modeling on Organizational Dynamics of Terrorist Network

    Directory of Open Access Journals (Sweden)

    Bo Li

    2015-01-01

    Full Text Available Modeling organizational dynamics of terrorist network is a critical issue in computational analysis of terrorism research. The first step for effective counterterrorism and strategic intervention is to investigate how the terrorists operate with the relational network and what affects the performance. In this paper, we investigate the organizational dynamics by employing a computational experimentation methodology. The hierarchical cellular network model and the organizational dynamics model are developed for modeling the hybrid relational structure and complex operational processes, respectively. To intuitively elucidate this method, the agent based modeling is used to simulate the terrorist network and test the performance in diverse scenarios. Based on the experimental results, we show how the changes of operational environments affect the development of terrorist organization in terms of its recovery and capacity to perform future tasks. The potential strategies are also discussed, which can be used to restrain the activities of terrorists.

  16. Modelling of robotic work cells using agent based-approach

    Science.gov (United States)

    Sękala, A.; Banaś, W.; Gwiazda, A.; Monica, Z.; Kost, G.; Hryniewicz, P.

    2016-08-01

    In the case of modern manufacturing systems the requirements, both according the scope and according characteristics of technical procedures are dynamically changing. This results in production system organization inability to keep up with changes in a market demand. Accordingly, there is a need for new design methods, characterized, on the one hand with a high efficiency and on the other with the adequate level of the generated organizational solutions. One of the tools that could be used for this purpose is the concept of agent systems. These systems are the tools of artificial intelligence. They allow assigning to agents the proper domains of procedures and knowledge so that they represent in a self-organizing system of an agent environment, components of a real system. The agent-based system for modelling robotic work cell should be designed taking into consideration many limitations considered with the characteristic of this production unit. It is possible to distinguish some grouped of structural components that constitute such a system. This confirms the structural complexity of a work cell as a specific production system. So it is necessary to develop agents depicting various aspects of the work cell structure. The main groups of agents that are used to model a robotic work cell should at least include next pattern representatives: machine tool agents, auxiliary equipment agents, robots agents, transport equipment agents, organizational agents as well as data and knowledge bases agents. In this way it is possible to create the holarchy of the agent-based system.

  17. Agent-based multi-optional model of innovations diffusion

    CERN Document Server

    Laciana, Carlos E

    2013-01-01

    We propose a formalism that allows the study of the process of diffusion of several products competing in a common market. It is based on the generalization of the statistics Ising model (Potts model). For the implementation, agent based modeling is used, applied to a problem of three options; to adopt a product A, a product B, or non-adoption. A launching strategy is analyzed for one of the two products, which delays its launching with the objective of competing with improvements. The proportion reached by one and another product is calculated at market saturation. The simulations are produced varying the social network topology, the uncertainty in the decision, and the population's homogeneity.

  18. Using Agent Based Modeling (ABM) to Develop Cultural Interaction Simulations

    Science.gov (United States)

    Drucker, Nick; Jones, Phillip N.

    2012-01-01

    Today, most cultural training is based on or built around "cultural engagements" or discrete interactions between the individual learner and one or more cultural "others". Often, success in the engagement is the end or the objective. In reality, these interactions usually involve secondary and tertiary effects with potentially wide ranging consequences. The concern is that learning culture within a strict engagement context might lead to "checklist" cultural thinking that will not empower learners to understand the full consequence of their actions. We propose the use of agent based modeling (ABM) to collect, store, and, simulating the effects of social networks, promulgate engagement effects over time, distance, and consequence. The ABM development allows for rapid modification to re-create any number of population types, extending the applicability of the model to any requirement for social modeling.

  19. Agent-based Modelling, a new kind of research

    DEFF Research Database (Denmark)

    Held, Fabian P.; Wilkinson, Ian F.; Marks, Robert E.;

    2014-01-01

    We discuss the use of Agent-based Modelling for the development and testing of theories about emergent social phenomena in marketing and the social sciences in general. We address both theoretical aspects about the types of phenomena that are suitably addressed with this approach and practical...... guidelines to help plan and structure the development of a theory about the causes of such a phenomenon in conjunction with a matching ABM. We argue that research about complex social phenomena is still largely fundamental research and therefore an iterative and cyclical development process of both theory...... and model is to be expected. To better anticipate and manage this process, we provide theoretical and practical guidelines. These may help to identify and structure the domain of candidate explanations for a social phenomenon, and furthermore assist the process of model implementation and subsequent...

  20. A Multi Agent Based Model for Airport Service Planning

    Directory of Open Access Journals (Sweden)

    W.H. Ip

    2010-09-01

    Full Text Available Aviation industry is highly dynamic and demanding in nature that time and safety are the two most important factors while one of the major sources of delay is aircraft on ground because of it complexity, a lot of machinery like vehicles are involved and lots of communication are involved. As one of the aircraft ground services providers in Hong Kong International Airport, China Aircraft Services Limited (CASL aims to increase competitiveness by better its service provided while minimizing cost is also needed. One of the ways is to optimize the number of maintenance vehicles allocated in order to minimize chance of delay and also operating costs. In the paper, an agent-based model is proposed for support decision making in vehicle allocation. The overview of the aircrafts ground services procedures is firstly mentioned with different optimization methods suggested by researchers. Then, the agent-based approach is introduced and in the latter part of report and a multi-agent system is built and proposed which is decision supportive for CASL in optimizing the maintenance vehicles' allocation. The application provides flexibility for inputting number of different kinds of vehicles, simulation duration and aircraft arrival rate in order to simulation different scenarios which occurs in HKIA.

  1. An Agent Based Modelling Approach for Multi-Stakeholder Analysis of City Logistics Solutions

    OpenAIRE

    Anand, N

    2015-01-01

    This thesis presents a comprehensive framework for multi-stakeholder analysis of city logistics solutions using agent based modeling. The framework describes different stages for the systematic development of an agent based model for the city logistics domain. The framework includes a multi-perspective city logistics ontology and its validation, the development of an agent base model using this ontology, and a validation approach for the agent based model using a participatory simulation game.

  2. Empirical agent-based land market: Integrating adaptive economic behavior in urban land-use models

    NARCIS (Netherlands)

    Filatova, Tatiana

    2015-01-01

    This paper introduces an economic agent-based model of an urban housing market. The RHEA (Risks and Hedonics in Empirical Agent-based land market) model captures natural hazard risks and environmental amenities through hedonic analysis, facilitating empirical agent-based land market modeling. RHEA i

  3. Complexity and agent-based modelling in urban research

    DEFF Research Database (Denmark)

    Fertner, Christian

    Urbanisation processes are results of a broad variety of actors or actor groups and their behaviour and decisions based on different experiences, knowledge, resources, values etc. The decisions done are often on a micro/individual level but resulting in macro/collective behaviour. In urban research...... influence on the bigger system. Traditional scientific methods or theories often tried to simplify, not accounting complex relations of actors and decision-making. The introduction of computers in simulation made new approaches in modelling, as for example agent-based modelling (ABM), possible, dealing...... of complexity for a majority of science, there exists a huge number of scientific articles, books, tutorials etc. to these topics which doesn’t make it easy for a novice in the field to find the right literature. The literature used gives an optimistic outlook for the future of this methodology, although ABM...

  4. Statistical Agent Based Modelization of the Phenomenon of Drug Abuse

    Science.gov (United States)

    di Clemente, Riccardo; Pietronero, Luciano

    2012-07-01

    We introduce a statistical agent based model to describe the phenomenon of drug abuse and its dynamical evolution at the individual and global level. The agents are heterogeneous with respect to their intrinsic inclination to drugs, to their budget attitude and social environment. The various levels of drug use were inspired by the professional description of the phenomenon and this permits a direct comparison with all available data. We show that certain elements have a great importance to start the use of drugs, for example the rare events in the personal experiences which permit to overcame the barrier of drug use occasionally. The analysis of how the system reacts to perturbations is very important to understand its key elements and it provides strategies for effective policy making. The present model represents the first step of a realistic description of this phenomenon and can be easily generalized in various directions.

  5. Statistical Agent Based Modelization of the Phenomenon of Drug Abuse

    CERN Document Server

    Di Clemente, Riccardo; 10.1038/srep00532

    2012-01-01

    We introduce a statistical agent based model to describe the phenomenon of drug abuse and its dynamical evolution at the individual and global level. The agents are heterogeneous with respect to their intrinsic inclination to drugs, to their budget attitude and social environment. The various levels of drug use were inspired by the professional description of the phenomenon and this permits a direct comparison with all available data. We show that certain elements have a great importance to start the use of drugs, for example the rare events in the personal experiences which permit to overcame the barrier of drug use occasionally. The analysis of how the system reacts to perturbations is very important to understand its key elements and it provides strategies for effective policy making. The present model represents the first step of a realistic description of this phenomenon and can be easily generalized in various directions.

  6. An agent-based model for energy service companies

    International Nuclear Information System (INIS)

    Highlights: • An agent-based model for household energy efficiency upgrades is considered. • Energy service companies provide an alternative to traditional utility providers. • Household self-financing is a limiting factor to widespread efficiency upgrading. • Longer term service contracts can lead to reduced household energy costs. • Future energy price increases enable service providers to retain their customer base. - Abstract: The residential housing sector is a major consumer of energy accounting for approximately one third of carbon emissions in the United Kingdom. Achieving a sustainable, low-carbon infrastructure necessitates a reduced and more efficient use of domestic energy supplies. Energy service companies offer an alternative to traditional providers, which supply a single utility product to satisfy the unconstrained demand of end users, and have been identified as a potentially important actor in sustainable future economies. An agent-based model is developed to examine the potential of energy service companies to contribute to the large scale upgrading of household energy efficiency, which would ultimately lead to a more sustainable and secure energy infrastructure. The migration of households towards energy service companies is described by an attractiveness array, through which potential customers can evaluate the future benefits, in terms of household energy costs, of changing provider. It is shown that self-financing is a limiting factor to the widespread upgrading of residential energy efficiency. Greater reductions in household energy costs could be achieved by committing to longer term contracts, allowing upgrade costs to be distributed over greater time intervals. A steadily increasing cost of future energy usage lends an element of stability to the market, with energy service companies displaying the ability to retain customers on contract expiration. The model highlights how a greater focus on the provision of energy services, as

  7. UML MODELING AND SYSTEM ARCHITECTURE FOR AGENT BASED INFORMATION RETRIEVAL

    Directory of Open Access Journals (Sweden)

    D. Muhammad Noorul Mubarak

    2015-12-01

    Full Text Available In this current technological era, there is an enormous increase in the information available on web and also in the online databases. This information abundance increases the complexity of finding relevant information. To solve such challenges, there is a need for improved and intelligent systems for efficient search and retrieval. Intelligent Agents can be used for better search and information retrieval in a document collection. The information required by a user is scattered in a large number of databases. In this paper, the object oriented modeling for agent based information retrieval system is presented. The paper also discusses the framework of agent architecture for obtaining the best combination terms that serve as an input query to the information retrieval system. The communication and cooperation among the agents are also explained. Each agent has a task to perform in information retrieval.

  8. Evaluating Water Demand Using Agent-Based Modeling

    Science.gov (United States)

    Lowry, T. S.

    2004-12-01

    The supply and demand of water resources are functions of complex, inter-related systems including hydrology, climate, demographics, economics, and policy. To assess the safety and sustainability of water resources, planners often rely on complex numerical models that relate some or all of these systems using mathematical abstractions. The accuracy of these models relies on how well the abstractions capture the true nature of the systems interactions. Typically, these abstractions are based on analyses of observations and/or experiments that account only for the statistical mean behavior of each system. This limits the approach in two important ways: 1) It cannot capture cross-system disruptive events, such as major drought, significant policy change, or terrorist attack, and 2) it cannot resolve sub-system level responses. To overcome these limitations, we are developing an agent-based water resources model that includes the systems of hydrology, climate, demographics, economics, and policy, to examine water demand during normal and extraordinary conditions. Agent-based modeling (ABM) develops functional relationships between systems by modeling the interaction between individuals (agents), who behave according to a probabilistic set of rules. ABM is a "bottom-up" modeling approach in that it defines macro-system behavior by modeling the micro-behavior of individual agents. While each agent's behavior is often simple and predictable, the aggregate behavior of all agents in each system can be complex, unpredictable, and different than behaviors observed in mean-behavior models. Furthermore, the ABM approach creates a virtual laboratory where the effects of policy changes and/or extraordinary events can be simulated. Our model, which is based on the demographics and hydrology of the Middle Rio Grande Basin in the state of New Mexico, includes agent groups of residential, agricultural, and industrial users. Each agent within each group determines its water usage

  9. Endogenizing geopolitical boundaries with agent-based modeling.

    Science.gov (United States)

    Cederman, Lars-Erik

    2002-05-14

    Agent-based modeling promises to overcome the reification of actors. Whereas this common, but limiting, assumption makes a lot of sense during periods characterized by stable actor boundaries, other historical junctures, such as the end of the Cold War, exhibit far-reaching and swift transformations of actors' spatial and organizational existence. Moreover, because actors cannot be assumed to remain constant in the long run, analysis of macrohistorical processes virtually always requires "sociational" endogenization. This paper presents a series of computational models, implemented with the software package REPAST, which trace complex macrohistorical transformations of actors be they hierarchically organized as relational networks or as collections of symbolic categories. With respect to the former, dynamic networks featuring emergent compound actors with agent compartments represented in a spatial grid capture organizational domination of the territorial state. In addition, models of "tagged" social processes allows the analyst to show how democratic states predicate their behavior on categorical traits. Finally, categorical schemata that select out politically relevant cultural traits in ethnic landscapes formalize a constructivist notion of national identity in conformance with the qualitative literature on nationalism. This "finite-agent method", representing both states and nations as higher-level structures superimposed on a lower-level grid of primitive agents or cultural traits, avoids reification of agency. Furthermore, it opens the door to explicit analysis of entity processes, such as the integration and disintegration of actors as well as boundary transformations. PMID:12011409

  10. Agent-based modeling to simulate the dengue spread

    Science.gov (United States)

    Deng, Chengbin; Tao, Haiyan; Ye, Zhiwei

    2008-10-01

    In this paper, we introduce a novel method ABM in simulating the unique process for the dengue spread. Dengue is an acute infectious disease with a long history of over 200 years. Unlike the diseases that can be transmitted directly from person to person, dengue spreads through a must vector of mosquitoes. There is still no any special effective medicine and vaccine for dengue up till now. The best way to prevent dengue spread is to take precautions beforehand. Thus, it is crucial to detect and study the dynamic process of dengue spread that closely relates to human-environment interactions where Agent-Based Modeling (ABM) effectively works. The model attempts to simulate the dengue spread in a more realistic way in the bottom-up way, and to overcome the limitation of ABM, namely overlooking the influence of geographic and environmental factors. Considering the influence of environment, Aedes aegypti ecology and other epidemiological characteristics of dengue spread, ABM can be regarded as a useful way to simulate the whole process so as to disclose the essence of the evolution of dengue spread.

  11. An Agent-Based Model of Institutional Life-Cycles

    Directory of Open Access Journals (Sweden)

    Manuel Wäckerle

    2014-08-01

    Full Text Available We use an agent-based model to investigate the interdependent dynamics between individual agency and emergent socioeconomic structure, leading to institutional change in a generic way. Our model simulates the emergence and exit of institutional units, understood as generic governed social structures. We show how endogenized trust and exogenously given leader authority influences institutional change, i.e., diversity in institutional life-cycles. It turns out that these governed institutions (destructure in cyclical patterns dependent on the overall evolution of trust in the artificial society, while at the same time, influencing this evolution by supporting social learning. Simulation results indicate three scenarios of institutional life-cycles. Institutions may, (1 build up very fast and freeze the artificial society in a stable but fearful pattern (ordered system; (2 exist only for a short time, leading to a very trusty society (highly fluctuating system; and (3 structure in cyclical patterns over time and support social learning due to cumulative causation of societal trust (complex system.

  12. Agent-based modelling of consumer energy choices

    Science.gov (United States)

    Rai, Varun; Henry, Adam Douglas

    2016-06-01

    Strategies to mitigate global climate change should be grounded in a rigorous understanding of energy systems, particularly the factors that drive energy demand. Agent-based modelling (ABM) is a powerful tool for representing the complexities of energy demand, such as social interactions and spatial constraints. Unlike other approaches for modelling energy demand, ABM is not limited to studying perfectly rational agents or to abstracting micro details into system-level equations. Instead, ABM provides the ability to represent behaviours of energy consumers -- such as individual households -- using a range of theories, and to examine how the interaction of heterogeneous agents at the micro-level produces macro outcomes of importance to the global climate, such as the adoption of low-carbon behaviours and technologies over space and time. We provide an overview of ABM work in the area of consumer energy choices, with a focus on identifying specific ways in which ABM can improve understanding of both fundamental scientific and applied aspects of the demand side of energy to aid the design of better policies and programmes. Future research needs for improving the practice of ABM to better understand energy demand are also discussed.

  13. Simulation of convoy of unmanned vehicles using agent based modeling

    Science.gov (United States)

    Sharma, Sharad; Singh, Harpreet; Gerhart, G. R.

    2007-10-01

    There has been an increasing interest of unmanned vehicles keeping the importance of defense and security. A few models for a convoy of unmanned vehicle exist in literature. The objective of this paper is to exploit agent based modeling technique for a convoy of unmanned vehicles where each vehicle is an agent. Using this approach, the convoy of vehicles reaches a specified goal from a starting point. Each agent is associated with number of sensors. The agents make intelligent decisions based on sensor inputs and at the same time maintaining their group capability and behavior. The simulation is done for a battlefield environment from a single starting point to a single goal. This approach can be extended for multiple starting points to reach multiple goals. The simulation gives the time taken by the convoy to reach a goal from its initial position. In the battlefield environment, commanders make various tactical decisions depending upon the location of an enemy outpost, minefields, number of soldiers in platoons, and barriers. The simulation can help the commander to make effective decisions depending on battlefield, convoy and obstacles to reach a particular goal. The paper describes the proposed approach and gives the simulation results. The paper also gives problems for future research in this area.

  14. E-laboratories : agent-based modeling of electricity markets.

    Energy Technology Data Exchange (ETDEWEB)

    North, M.; Conzelmann, G.; Koritarov, V.; Macal, C.; Thimmapuram, P.; Veselka, T.

    2002-05-03

    Electricity markets are complex adaptive systems that operate under a wide range of rules that span a variety of time scales. These rules are imposed both from above by society and below by physics. Many electricity markets are undergoing or are about to undergo a transition from centrally regulated systems to decentralized markets. Furthermore, several electricity markets have recently undergone this transition with extremely unsatisfactory results, most notably in California. These high stakes transitions require the introduction of largely untested regulatory structures. Suitable laboratories that can be used to test regulatory structures before they are applied to real systems are needed. Agent-based models can provide such electronic laboratories or ''e-laboratories.'' To better understand the requirements of an electricity market e-laboratory, a live electricity market simulation was created. This experience helped to shape the development of the Electricity Market Complex Adaptive Systems (EMCAS) model. To explore EMCAS' potential as an e-laboratory, several variations of the live simulation were created. These variations probed the possible effects of changing power plant outages and price setting rules on electricity market prices.

  15. Modeling of Agile Manufacturing Execution Systems with an Agent-based Approach

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Agile manufacturing execution systems (AMES) are used to help manufacturers optimize shop floor production in an agile way. And the modeling of AMES is the key issue of realizing AMES. This paper presents an agent-based approach to AMES modeling. Firstly, the characteristics of AMES and its requirements on modeling are discussed. Secondly, a comparative analysis of modeling methods is carried out, and AMES modeling using an agent-based approach is put forward. Agent-based modeling method not only inherit ...

  16. Validation techniques of agent based modelling for geospatial simulations

    Science.gov (United States)

    Darvishi, M.; Ahmadi, G.

    2014-10-01

    One of the most interesting aspects of modelling and simulation study is to describe the real world phenomena that have specific properties; especially those that are in large scales and have dynamic and complex behaviours. Studying these phenomena in the laboratory is costly and in most cases it is impossible. Therefore, Miniaturization of world phenomena in the framework of a model in order to simulate the real phenomena is a reasonable and scientific approach to understand the world. Agent-based modelling and simulation (ABMS) is a new modelling method comprising of multiple interacting agent. They have been used in the different areas; for instance, geographic information system (GIS), biology, economics, social science and computer science. The emergence of ABM toolkits in GIS software libraries (e.g. ESRI's ArcGIS, OpenMap, GeoTools, etc) for geospatial modelling is an indication of the growing interest of users to use of special capabilities of ABMS. Since ABMS is inherently similar to human cognition, therefore it could be built easily and applicable to wide range applications than a traditional simulation. But a key challenge about ABMS is difficulty in their validation and verification. Because of frequent emergence patterns, strong dynamics in the system and the complex nature of ABMS, it is hard to validate and verify ABMS by conventional validation methods. Therefore, attempt to find appropriate validation techniques for ABM seems to be necessary. In this paper, after reviewing on Principles and Concepts of ABM for and its applications, the validation techniques and challenges of ABM validation are discussed.

  17. Using the Agent-Based Modeling in Economic Field

    Directory of Open Access Journals (Sweden)

    Nora Mihail

    2006-12-01

    Full Text Available The last ten years of the XX century has been the witnesses of the apparition of a new scientific field, which is usually defined as the study of “Complex adaptive systems”. This field, generic named Complexity Sciences, shares its subject, the general proprieties of complex systems across traditional disciplinary boundaries, with cybernetics and general systems theory. But the development of Complexity Sciences approaches is determined by the extensive use of Agent-Based-Models (ABM as a research tool and an emphasis on systems, such as markets, populations or ecologies, which are less integrated or “organized” than the ones, such as companies and economies, intensively studied by the traditional disciplines. For ABM, a complex system is a system of individual agents who have the freedom to act in ways that are not always totally predictable, and whose actions are interconnected such that one agent’s actions changes the context (environment for other agents. These are many examples of such complex systems: the stock market, the human body immune system, a business organization, an institution, a work-team, a family etc.

  18. Using FLAME Toolkit for Agent-Based Simulation: Case Study Sugarscape Model

    OpenAIRE

    Kiran, Mariam

    2014-01-01

    Social scientists have used agent-based models to understand how individuals interact and behave in various political, ecological and economic scenarios. Agent-based models are ideal for understanding such models involving interacting individuals producing emergent phenomenon. Sugarscape is one of the most famous examples of a social agent-based model which has been used to show how societies grow in the real world. This paper builds on the Sugarscape model, using the Flexible Large scale Age...

  19. An Introduction to Agent Based Modelling and Simulation of Social Processes

    OpenAIRE

    Ognjen Skunca; Armano Srbljinovic

    2003-01-01

    The paper provides an introduction to agent-based modelling and simulation of social processes. Reader is introduced to the worldview underlying agent-based models, some basic terminology, basic properties of agent-based models, as well as to what one can and what cannot expect from such models, particularly when they are applied to social-scientific investigation. Special attention is given to the issues of validation.

  20. Agent-Based Modelling: Tools for Linking NetLogo and r

    OpenAIRE

    Jan C Thiele; Winfried Kurth; Volker Grimm

    2012-01-01

    A seamless integration of software platforms for implementing agent-based models and for analysing their output would facilitate comprehensive model analyses and thereby make agent-based modelling more useful. Here we report on recently developed tools for linking two widely used software platforms: NetLogo for implementing agent-based models, and R for the statistical analysis and design of experiments. Embedding R into NetLogo allows the use of advanced statistical analyses, specific statis...

  1. A Systematic Review of Agent-Based Modelling and Simulation Applications in the Higher Education Domain

    Science.gov (United States)

    Gu, X.; Blackmore, K. L.

    2015-01-01

    This paper presents the results of a systematic review of agent-based modelling and simulation (ABMS) applications in the higher education (HE) domain. Agent-based modelling is a "bottom-up" modelling paradigm in which system-level behaviour (macro) is modelled through the behaviour of individual local-level agent interactions (micro).…

  2. Opinion transmission in organizations: an agent-based modeling approach

    OpenAIRE

    Rouchier, Juliette; Tubaro, Paola; Emery, Cécile

    2014-01-01

    This paper builds a theoretical framework to detect the conditions under which social influence enables persistence of a shared opinion among members of an organization over time, despite membership turnover. It develops agent-based simulations of opinion evolution in an advice network, whereby opinion is defined in the broad sense of shared understandings on a matter that is relevant for an organization’s activities, and on which members have some degree of discretion. We combine a micro-lev...

  3. Multi-level agent-based modeling with the Influence Reaction principle

    OpenAIRE

    Morvan, Gildas; Jolly, Daniel

    2012-01-01

    This paper deals with the specification and the implementation of multi-level agent-based models, using a formal model, IRM4MLS (an Influence Reaction Model for Multi-Level Simulation), based on the Influence Reaction principle. Proposed examples illustrate forms of top-down control in (multi-level) multi-agent based-simulations.

  4. Macroeconomic Fluctuations and Propagation Mechanisms: An Agent-Based Simulation Model

    OpenAIRE

    Sella Lisa

    2009-01-01

    This paper proposes an agent-based simulation model exploring aggregate business fluctuations in an artificial market economy. It is inspired by the C++ agent-based simulation model in Howitt (2006), and proposes a modified NetLogo model, which provides new procedures and parameters aiming at analyzing the endogenous dynamics of market adjustment processes

  5. Agent-based modeling and systems dynamics model reproduction.

    Energy Technology Data Exchange (ETDEWEB)

    North, M. J.; Macal, C. M. (Decision and Information Sciences)

    2009-01-01

    Reproducibility is a pillar of the scientific endeavour. We view computer simulations as laboratories for electronic experimentation and therefore as tools for science. Recent studies have addressed model reproduction and found it to be surprisingly difficult to replicate published findings. There have been enough failed simulation replications to raise the question, 'can computer models be fully replicated?' This paper answers in the affirmative by reporting on a successful reproduction study using Mathematica, Repast and Swarm for the Beer Game supply chain model. The reproduction process was valuable because it demonstrated the original result's robustness across modelling methodologies and implementation environments.

  6. An Agent Based Modelling Approach for Multi-Stakeholder Analysis of City Logistics Solutions

    NARCIS (Netherlands)

    Anand, N.

    2015-01-01

    This thesis presents a comprehensive framework for multi-stakeholder analysis of city logistics solutions using agent based modeling. The framework describes different stages for the systematic development of an agent based model for the city logistics domain. The framework includes a multi-perspect

  7. A review of urban residential choice models using agent-based modeling

    NARCIS (Netherlands)

    Huang, Qingxu; Parker, Dawn C.; Filatova, Tatiana; Sun, Shipeng

    2014-01-01

    Urban land-use modeling methods have experienced substantial improvements in the last several decades. With the advancement of urban land-use change theories and modeling techniques, a considerable number of models have been developed. The relatively young approach, agent-based modeling, provides ur

  8. Brief introductory guide to agent-based modeling and an illustration from urban health research.

    Science.gov (United States)

    Auchincloss, Amy H; Garcia, Leandro Martin Totaro

    2015-11-01

    There is growing interest among urban health researchers in addressing complex problems using conceptual and computation models from the field of complex systems. Agent-based modeling (ABM) is one computational modeling tool that has received a lot of interest. However, many researchers remain unfamiliar with developing and carrying out an ABM, hindering the understanding and application of it. This paper first presents a brief introductory guide to carrying out a simple agent-based model. Then, the method is illustrated by discussing a previously developed agent-based model, which explored inequalities in diet in the context of urban residential segregation. PMID:26648364

  9. Brief introductory guide to agent-based modeling and an illustration from urban health research

    Directory of Open Access Journals (Sweden)

    Amy H. Auchincloss

    2015-11-01

    Full Text Available Abstract There is growing interest among urban health researchers in addressing complex problems using conceptual and computation models from the field of complex systems. Agent-based modeling (ABM is one computational modeling tool that has received a lot of interest. However, many researchers remain unfamiliar with developing and carrying out an ABM, hindering the understanding and application of it. This paper first presents a brief introductory guide to carrying out a simple agent-based model. Then, the method is illustrated by discussing a previously developed agent-based model, which explored inequalities in diet in the context of urban residential segregation.

  10. Practicality of Agent-Based Modeling of Civil Violence: an Assessment

    CERN Document Server

    Thron, Christopher

    2015-01-01

    Joshua Epstein (2002) proposed a simple agent-based model to describe the formation and evolution of spontaneous civil violence (such as riots or violent demonstrations). In this paper we study the practical applicability of Epstein's model.

  11. Agent-based land-use models: a review of applications

    OpenAIRE

    Matthews, RB; Gilbert, NG; Roach, A.; Polhill, JG; Gotts, NM

    2007-01-01

    Agent-based modelling is an approach that has been receiving attention by the land use modelling community in recent years, mainly because it offers a way of incorporating the influence of human decision-making on land use in a mechanistic, formal, and spatially explicit way, taking into account social interaction, adaptation, and decision-making at different levels. Specific advantages of agent-based models include their ability to model individual decision-making entities and their interact...

  12. Pattern-Oriented Modeling of Agent-Based Complex Systems: Lessons from Ecology

    OpenAIRE

    Grimm, Volker; Revilla, Eloy; Berger, Uta; Jeltsch, Florian; Mooij, Wolf M.; Railsback, Steven F.; Thulke, Hans-Hermann; Weiner, Jacob; Wiegand, Thorsten; Donald L DeAngelis

    2005-01-01

    Agent-based complex systems are dynamic networks of many interacting agents; examples include ecosystems, financial markets, and cities. The search for general principles underlying the internal organization of such systems often uses bottom-up simulation models such as cellular automata and agent-based models. No general framework for designing, testing, and analyzing bottom-up models has yet been established, but recent advances in ecological modeling have come together in a genera...

  13. Predictability of Shanghai Stock Market by Agent-based Mix-game Model

    CERN Document Server

    Gou, C

    2005-01-01

    This paper reports the effort of using agent-based mix-game model to predict financial time series. It introduces the prediction methodology by means of mix-game model and gives an example of its application to forecasting Shanghai Index. The results show that this prediction methodology is effective and agent-based mix-game model is a potential good model to predict time series of financial markets.

  14. Comparing Stochastic Differential Equations and Agent-Based Modelling and Simulation for Early-Stage Cancer

    OpenAIRE

    Figueredo, Grazziela P.; Peer-Olaf Siebers; Owen, Markus R.; Jenna Reps; Uwe Aickelin

    2014-01-01

    There is great potential to be explored regarding the use of agent-based modelling and simulation as an alternative paradigm to investigate early-stage cancer interactions with the immune system. It does not suffer from some limitations of ordinary differential equation models, such as the lack of stochasticity, representation of individual behaviours rather than aggregates and individual memory. In this paper we investigate the potential contribution of agent-based modelling and simulation w...

  15. Exploring the World of Agent-Based Simulations: Simple Models, Complex Analyses

    OpenAIRE

    Sanchez, Susan M.; Lucas, Thomas W.

    2002-01-01

    Proceedings of the 2002 Winter Simulation Conference E. Yücesan, C.-H. Chen, J. L. Snowdon, and J. M. Charnes, eds. Agent-based simulations are models where multiple entities sense and stochastically respond to conditions in their local environments, mimicking complex large-scale system behavior. We provide an overview of some important issues in the modeling and analysis of agent-based systems. Examples are drawn from a range of fields: biological modeling, sociologic...

  16. Simulating tissue mechanics with agent-based models: concepts, perspectives and some novel results

    Science.gov (United States)

    Van Liedekerke, P.; Palm, M. M.; Jagiella, N.; Drasdo, D.

    2015-12-01

    In this paper we present an overview of agent-based models that are used to simulate mechanical and physiological phenomena in cells and tissues, and we discuss underlying concepts, limitations, and future perspectives of these models. As the interest in cell and tissue mechanics increase, agent-based models are becoming more common the modeling community. We overview the physical aspects, complexity, shortcomings, and capabilities of the major agent-based model categories: lattice-based models (cellular automata, lattice gas cellular automata, cellular Potts models), off-lattice models (center-based models, deformable cell models, vertex models), and hybrid discrete-continuum models. In this way, we hope to assist future researchers in choosing a model for the phenomenon they want to model and understand. The article also contains some novel results.

  17. Getting away from numbers: Using qualitative observation for agent-based modeling

    OpenAIRE

    Yang, L; Gilbert, N.

    2008-01-01

    Although in many social sciences there is a radical division between studies based on quantitative (e.g. statistical) and qualitative (e.g. ethnographic) methodologies and their associated epistemological commitments, agent-based simulation fits into neither camp, and should be capable of modelling both quantitative and qualitative data. Nevertheless, most agent-based models (ABMs) are founded on quantitative data. This paper explores some of the methodological and practical problems involved...

  18. Agent-based modeling: Methods and techniques for simulating human systems

    OpenAIRE

    Bonabeau, Eric

    2002-01-01

    Agent-based modeling is a powerful simulation modeling technique that has seen a number of applications in the last few years, including applications to real-world business problems. After the basic principles of agent-based simulation are briefly introduced, its four areas of application are discussed by using real-world applications: flow simulation, organizational simulation, market simulation, and diffusion simulation. For each category, one or several business applications are described ...

  19. Using an agent-based model to simulate children’s active travel to school

    OpenAIRE

    Yang, Yong; Diez-Roux, Ana V.

    2013-01-01

    Background Despite the multiple advantages of active travel to school, only a small percentage of US children and adolescents walk or bicycle to school. Intervention studies are in a relatively early stage and evidence of their effectiveness over long periods is limited. The purpose of this study was to illustrate the utility of agent-based models in exploring how various policies may influence children’s active travel to school. Methods An agent-based model was developed to simulate children...

  20. Disaggregation and Refinement of System Dynamics Models via Agent-based Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Nutaro, James J [ORNL; Ozmen, Ozgur [ORNL; Schryver, Jack C [ORNL

    2014-01-01

    System dynamics models are usually used to investigate aggregate level behavior, but these models can be decomposed into agents that have more realistic individual behaviors. Here we develop a simple model of the STEM workforce to illuminate the impacts that arise from the disaggregation and refinement of system dynamics models via agent-based modeling. Particularly, alteration of Poisson assumptions, adding heterogeneity to decision-making processes of agents, and discrete-time formulation are investigated and their impacts are illustrated. The goal is to demonstrate both the promise and danger of agent-based modeling in the context of a relatively simple model and to delineate the importance of modeling decisions that are often overlooked.

  1. Comparing large-scale computational approaches to epidemic modeling: Agent-based versus structured metapopulation models

    Directory of Open Access Journals (Sweden)

    Merler Stefano

    2010-06-01

    Full Text Available Abstract Background In recent years large-scale computational models for the realistic simulation of epidemic outbreaks have been used with increased frequency. Methodologies adapt to the scale of interest and range from very detailed agent-based models to spatially-structured metapopulation models. One major issue thus concerns to what extent the geotemporal spreading pattern found by different modeling approaches may differ and depend on the different approximations and assumptions used. Methods We provide for the first time a side-by-side comparison of the results obtained with a stochastic agent-based model and a structured metapopulation stochastic model for the progression of a baseline pandemic event in Italy, a large and geographically heterogeneous European country. The agent-based model is based on the explicit representation of the Italian population through highly detailed data on the socio-demographic structure. The metapopulation simulations use the GLobal Epidemic and Mobility (GLEaM model, based on high-resolution census data worldwide, and integrating airline travel flow data with short-range human mobility patterns at the global scale. The model also considers age structure data for Italy. GLEaM and the agent-based models are synchronized in their initial conditions by using the same disease parameterization, and by defining the same importation of infected cases from international travels. Results The results obtained show that both models provide epidemic patterns that are in very good agreement at the granularity levels accessible by both approaches, with differences in peak timing on the order of a few days. The relative difference of the epidemic size depends on the basic reproductive ratio, R0, and on the fact that the metapopulation model consistently yields a larger incidence than the agent-based model, as expected due to the differences in the structure in the intra-population contact pattern of the approaches. The age

  2. Tutorial on agent-based modeling and simulation. Part 2 : how to model with agents.

    Energy Technology Data Exchange (ETDEWEB)

    Macal, C. M.; North, M. J.; Decision and Information Sciences

    2006-01-01

    Agent-based modeling and simulation (ABMS) is a new approach to modeling systems comprised of interacting autonomous agents. ABMS promises to have far-reaching effects on the way that businesses use computers to support decision-making and researchers use electronic laboratories to do research. Some have gone so far as to contend that ABMS is a new way of doing science. Computational advances make possible a growing number of agent-based applications across many fields. Applications range from modeling agent behavior in the stock market and supply chains, to predicting the spread of epidemics and the threat of bio-warfare, from modeling the growth and decline of ancient civilizations to modeling the complexities of the human immune system, and many more. This tutorial describes the foundations of ABMS, identifies ABMS toolkits and development methods illustrated through a supply chain example, and provides thoughts on the appropriate contexts for ABMS versus conventional modeling techniques.

  3. An Agent-Based Model of Behavior in “Beauty Contest” Games

    OpenAIRE

    Nichols, Mark W.; Michael J. Radzicki

    2007-01-01

    Recently, computer simulation, particularly agent-based modeling, has grown in popularity as a method to uncover macro patterns and developments that emerge from simple micro behavior. The present paper combines both techniques by using protocol analysis to uncover player strategies in an experiment and encoding those strategies in an agent-based computer simulation. In particular, Keynes’ (1936) beauty contest analogy is simulated in a number-guessing context. Several researchers have conduc...

  4. Model-Drive Architecture for Agent-Based Systems

    Science.gov (United States)

    Gradanin, Denis; Singh, H. Lally; Bohner, Shawn A.; Hinchey, Michael G.

    2004-01-01

    The Model Driven Architecture (MDA) approach uses a platform-independent model to define system functionality, or requirements, using some specification language. The requirements are then translated to a platform-specific model for implementation. An agent architecture based on the human cognitive model of planning, the Cognitive Agent Architecture (Cougaar) is selected for the implementation platform. The resulting Cougaar MDA prescribes certain kinds of models to be used, how those models may be prepared and the relationships of the different kinds of models. Using the existing Cougaar architecture, the level of application composition is elevated from individual components to domain level model specifications in order to generate software artifacts. The software artifacts generation is based on a metamodel. Each component maps to a UML structured component which is then converted into multiple artifacts: Cougaar/Java code, documentation, and test cases.

  5. Agent Based Modeling on Organizational Dynamics of Terrorist Network

    OpenAIRE

    Bo Li; Duoyong Sun; Renqi Zhu; Ze Li

    2015-01-01

    Modeling organizational dynamics of terrorist network is a critical issue in computational analysis of terrorism research. The first step for effective counterterrorism and strategic intervention is to investigate how the terrorists operate with the relational network and what affects the performance. In this paper, we investigate the organizational dynamics by employing a computational experimentation methodology. The hierarchical cellular network model and the organizational dynamics model ...

  6. Agent-based model of information spread in social networks

    CERN Document Server

    Lande, D V; Berezin, B O

    2016-01-01

    We propose evolution rules of the multiagent network and determine statistical patterns in life cycle of agents - information messages. The main discussed statistical pattern is connected with the number of likes and reposts for a message. This distribution corresponds to Weibull distribution according to modeling results. We examine proposed model using the data from Twitter, an online social networking service.

  7. An Agent-Based Approach to Modeling Online Social Influence

    NARCIS (Netherlands)

    Maanen, P.P. van; Vecht, B. van der

    2013-01-01

    The aim of this study is to better understand social influence in online social media. Therefore, we propose a method in which we implement, validate and improve an individual behavior model. The behavior model is based on three fundamental behavioral principles of social influence from the literatu

  8. Agent based models for wealth distribution with preference in interaction

    CERN Document Server

    Goswami, Sanchari

    2014-01-01

    We propose a set of conservative models in which agents exchange wealth with a preference in the choice of interacting agents in different ways. The common feature in all the models is that the temporary values of financial status of agents is a deciding factor for interaction. Other factors which may play important role are past interactions and wealth possessed by individuals. Wealth distribution, network properties and activity are the main quantities which have been studied. Evidence of phase transitions and other interesting features are presented. The results show that certain observations of real economic system can be reproduced by the models.

  9. Multi-agent Based Modeling of Manufacturing Network

    Institute of Scientific and Technical Information of China (English)

    GUO Yuming; SUN Yanming; ZHENG Shixiong

    2006-01-01

    An intelligent manufacturing system is modeled currently from the viewpoint of manufacturing applications, and the network platform's influence to manufacturing applications is not considered adequately. However any bottleneck in service oriented architecture (SOA) for the manufacturing network can affect the agility of the IT environment. In this paper, to achieve a trade-off between manufacturing resources and network resources, the manufacturing network is modeled with multi-agent, in which two kinds of basic elements, the manufacturing application unit and the network carrier of manufacturing information, are presented. And their main characters are described by colored petri net. The manufacturing application model drives the network platform that inversely provides this application model technology supports. The proposed multi-agent system is demonstrated through an example integration scenario involving production plan, resources management and execution subsystems. And the result suggests that analyzing and designing the system architecture of networked manufacturing should give due attention to the operation system as well as manufacturing applications.

  10. Agent based modeling of the coevolution of hostility and pacifism

    Science.gov (United States)

    Dalmagro, Fermin; Jimenez, Juan

    2015-01-01

    We propose a model based on a population of agents whose states represent either hostile or peaceful behavior. Randomly selected pairs of agents interact according to a variation of the Prisoners Dilemma game, and the probabilities that the agents behave aggressively or not are constantly updated by the model so that the agents that remain in the game are those with the highest fitness. We show that the population of agents oscillate between generalized conflict and global peace, without either reaching a stable state. We then use this model to explain some of the emergent behaviors in collective conflicts, by comparing the simulated results with empirical data obtained from social systems. In particular, using public data reports we show how the model precisely reproduces interesting quantitative characteristics of diverse types of armed conflicts, public protests, riots and strikes.

  11. Agent-Based Model for Pedestrians’ Evacuation after a Blast Integrated with a Human Behavior Model

    OpenAIRE

    PLUCHINO Salvatore; TRIBOLATO Chiara; CAVERZAN ALESSIO; MC QUILLAN Alexandro; Cimellaro, Gian Paolo; MAHIN Stephen A.

    2015-01-01

    Agent-based modeling (ABM) is a powerful tool for model complex and heterogeneous systems as pedestrian evacuation after extreme events. Several studies on Emergency Management exist in literature, but the majority of them do not consider how human behavior impacts the evacuation plan. Indeed, these can change drastically a critical scenario because are driven by emotions, knowledge and perception which are unpredictable. The aim of this study is to develop an ABM of an evacuation scenario du...

  12. Agent-based Modeling and Mapping of Manufacturing System

    Institute of Scientific and Technical Information of China (English)

    Z; Zhang

    2002-01-01

    Considering the gent-based modeling and mapping in m anufacturing system, in this paper, some system models are described, which are including: Domain Based Hierarchical Structure (DBHS), Cascading Agent Struc ture (CAS), Proximity Relation structure (PRS), and Bus-based network structure (BNS). In DBHS, one sort of agent individually delegates Domain Agents, Res ources Agents, UserInterface Agents and Gateway Agents and the other one is a br oker of tasks and process flow. Static agents representing...

  13. Capturing socio-technical systems with agent-based modelling

    NARCIS (Netherlands)

    Van Dam, K.H.

    2009-01-01

    What is a suitable modelling approach for socio-technical systems? The answer to this question is of great importance to decision makers in large scale interconnected network systems. The behaviour of these systems is determined by many actors, situated in a dynamic, multi-actor, multi-objective and

  14. Econophysics: Empirical facts and agent-based models

    OpenAIRE

    Anirban Chakraborti; Ioane Muni Toke; Marco Patriarca; Frederic Abergel

    2009-01-01

    This article aims at reviewing recent empirical and theoretical developments usually grouped under the term Econophysics. Since its name was coined in 1995 by merging the words Economics and Physics, this new interdisciplinary field has grown in various directions: theoretical macroeconomics (wealth distributions), microstructure of financial markets (order book modelling), econometrics of financial bubbles and crashes, etc. In the first part of the review, we discuss on the emergence of Econ...

  15. Agent-based and individual-based modeling a practical introduction

    CERN Document Server

    Railsback, Steven F

    2011-01-01

    Agent-based modeling is a new technique for understanding how the dynamics of biological, social, and other complex systems arise from the characteristics and behaviors of the agents making up these systems. This innovative textbook gives students and scientists the skills to design, implement, and analyze agent-based models. It starts with the fundamentals of modeling and provides an introduction to NetLogo, an easy-to-use, free, and powerful software platform. Nine chapters then each introduce an important modeling concept and show how to implement it using NetLogo. The book goes on to pres

  16. An Agent-Based Model for Studying Child Maltreatment and Child Maltreatment Prevention

    Science.gov (United States)

    Hu, Xiaolin; Puddy, Richard W.

    This paper presents an agent-based model that simulates the dynamics of child maltreatment and child maltreatment prevention. The developed model follows the principles of complex systems science and explicitly models a community and its families with multi-level factors and interconnections across the social ecology. This makes it possible to experiment how different factors and prevention strategies can affect the rate of child maltreatment. We present the background of this work and give an overview of the agent-based model and show some simulation results.

  17. Using Agent Base Models to Optimize Large Scale Network for Large System Inventories

    Science.gov (United States)

    Shameldin, Ramez Ahmed; Bowling, Shannon R.

    2010-01-01

    The aim of this paper is to use Agent Base Models (ABM) to optimize large scale network handling capabilities for large system inventories and to implement strategies for the purpose of reducing capital expenses. The models used in this paper either use computational algorithms or procedure implementations developed by Matlab to simulate agent based models in a principal programming language and mathematical theory using clusters, these clusters work as a high performance computational performance to run the program in parallel computational. In both cases, a model is defined as compilation of a set of structures and processes assumed to underlie the behavior of a network system.

  18. Model reduction for agent-based social simulation: Coarse-graining a civil violence model

    Science.gov (United States)

    Zou, Yu; Fonoberov, Vladimir A.; Fonoberova, Maria; Mezic, Igor; Kevrekidis, Ioannis G.

    2012-06-01

    Agent-based modeling (ABM) constitutes a powerful computational tool for the exploration of phenomena involving emergent dynamic behavior in the social sciences. This paper demonstrates a computer-assisted approach that bridges the significant gap between the single-agent microscopic level and the macroscopic (coarse-grained population) level, where fundamental questions must be rationally answered and policies guiding the emergent dynamics devised. Our approach will be illustrated through an agent-based model of civil violence. This spatiotemporally varying ABM incorporates interactions between a heterogeneous population of citizens [active (insurgent), inactive, or jailed] and a population of police officers. Detailed simulations exhibit an equilibrium punctuated by periods of social upheavals. We show how to effectively reduce the agent-based dynamics to a stochastic model with only two coarse-grained degrees of freedom: the number of jailed citizens and the number of active ones. The coarse-grained model captures the ABM dynamics while drastically reducing the computation time (by a factor of approximately 20).

  19. Model reduction for agent-based social simulation: coarse-graining a civil violence model.

    Science.gov (United States)

    Zou, Yu; Fonoberov, Vladimir A; Fonoberova, Maria; Mezic, Igor; Kevrekidis, Ioannis G

    2012-06-01

    Agent-based modeling (ABM) constitutes a powerful computational tool for the exploration of phenomena involving emergent dynamic behavior in the social sciences. This paper demonstrates a computer-assisted approach that bridges the significant gap between the single-agent microscopic level and the macroscopic (coarse-grained population) level, where fundamental questions must be rationally answered and policies guiding the emergent dynamics devised. Our approach will be illustrated through an agent-based model of civil violence. This spatiotemporally varying ABM incorporates interactions between a heterogeneous population of citizens [active (insurgent), inactive, or jailed] and a population of police officers. Detailed simulations exhibit an equilibrium punctuated by periods of social upheavals. We show how to effectively reduce the agent-based dynamics to a stochastic model with only two coarse-grained degrees of freedom: the number of jailed citizens and the number of active ones. The coarse-grained model captures the ABM dynamics while drastically reducing the computation time (by a factor of approximately 20).

  20. Agent-based modeling of lane discipline in heterogeneous traffic

    Science.gov (United States)

    Dailisan, Damian N.; Lim, May T.

    2016-09-01

    Designating lanes for different vehicle types is ideal road safety-wise. Practical considerations, however, require road sharing. Using a modified Nagel-Schreckenberg cellular automata model for two vehicle types (cars and motorcycles), we analyzed the interplay of lane discipline, lane changing, and vehicle density. In the absence of lane changing, the transition between free flow and congested states occurs at a higher vehicle (road occupation) density when the ratio of cars to motorcycles is increased. When lane changing is allowed, the smaller motorcycles tend to fill in unused spaces, until the point when the wider cars effectively block their way at high vehicle densities. When the condition of lane discipline is not imposed, i.e. staying wholly within lane boundaries is not required, further improvement in throughput becomes possible at the cost of required driver attentiveness.

  1. Signal amplification in an agent-based herding model

    CERN Document Server

    Carro, Adrián; Miguel, Maxi San

    2013-01-01

    A growing part of the behavioral finance literature has addressed some of the stylized facts of financial time series as macroscopic patterns emerging from herding interactions among groups of agents with heterogeneous trading strategies and a limited rationality. We extend a stochastic herding formalism introduced for the modeling of decision making among financial agents, in order to take also into account an external influence. In particular, we study the amplification of an external signal imposed upon the agents by a mechanism of resonance. This signal can be interpreted as an advertising or a public perception in favor or against one of the two possible trading behaviors, thus periodically breaking the symmetry of the system and acting as a continuously varying exogenous shock. The conditions for the ensemble of agents to more accurately follow the periodicity of the signal are studied, finding a maximum in the response of the system for a given range of values of both the noise and the frequency of the...

  2. Crisis response simulation combining discrete-event and agent-based modeling

    NARCIS (Netherlands)

    Gonzalez, R.A.

    2009-01-01

    This paper presents a crisis response simulation model architecture combining a discrete-event simulation (DES) environment for a crisis scenario with an agent-based model of the response organization. In multi-agent systems (MAS) as a computational organization, agents are modeled and implemented s

  3. Agent-based models for higher-order theory of mind

    NARCIS (Netherlands)

    de Weerd, Harmen; Verbrugge, Rineke; Verheij, Bart; Kamiński, Bogumił; Koloch, Grzegorz

    2014-01-01

    Agent-based models are a powerful tool for explaining the emergence of social phenomena in a society. In such models, individual agents typically have little cognitive ability. In this paper, we model agents with the cognitive ability to make use of theory of mind. People use this ability to reason

  4. Demeter, persephone, and the search for emergence in agent-based models.

    Energy Technology Data Exchange (ETDEWEB)

    North, M. J.; Howe, T. R.; Collier, N. T.; Vos, J. R.; Decision and Information Sciences; Univ. of Chicago; PantaRei Corp.; Univ. of Illinois

    2006-01-01

    In Greek mythology, the earth goddess Demeter was unable to find her daughter Persephone after Persephone was abducted by Hades, the god of the underworld. Demeter is said to have embarked on a long and frustrating, but ultimately successful, search to find her daughter. Unfortunately, long and frustrating searches are not confined to Greek mythology. In modern times, agent-based modelers often face similar troubles when searching for agents that are to be to be connected to one another and when seeking appropriate target agents while defining agent behaviors. The result is a 'search for emergence' in that many emergent or potentially emergent behaviors in agent-based models of complex adaptive systems either implicitly or explicitly require search functions. This paper considers a new nested querying approach to simplifying such agent-based modeling and multi-agent simulation search problems.

  5. Techniques, Advantages and Problems of Agent Based Modeling for Traffic Simulation

    Directory of Open Access Journals (Sweden)

    Ali Bazghandi

    2012-01-01

    Full Text Available Agent-based modeling (ABM is a powerful simulation modeling technique in the last few years. ABM, as an approach to simulating the behavior of a complex system in which agents interact with each other and with their environment using simple local rules, is gaining popularity and widespread use in many areas. Successes of this approach in predicting traffic flow in metropolitan areas, the spread of infectious diseases, and the behavior of economic systems have generated further interest in this powerful technology. In this paper we focus on agent-based approach to traffic simulation, and investigate its benefits, difficulties and (microscopic-macroscopic techniques.

  6. Consentaneous agent-based and stochastic model of the financial markets.

    Science.gov (United States)

    Gontis, Vygintas; Kononovicius, Aleksejus

    2014-01-01

    We are looking for the agent-based treatment of the financial markets considering necessity to build bridges between microscopic, agent based, and macroscopic, phenomenological modeling. The acknowledgment that agent-based modeling framework, which may provide qualitative and quantitative understanding of the financial markets, is very ambiguous emphasizes the exceptional value of well defined analytically tractable agent systems. Herding as one of the behavior peculiarities considered in the behavioral finance is the main property of the agent interactions we deal with in this contribution. Looking for the consentaneous agent-based and macroscopic approach we combine two origins of the noise: exogenous one, related to the information flow, and endogenous one, arising form the complex stochastic dynamics of agents. As a result we propose a three state agent-based herding model of the financial markets. From this agent-based model we derive a set of stochastic differential equations, which describes underlying macroscopic dynamics of agent population and log price in the financial markets. The obtained solution is then subjected to the exogenous noise, which shapes instantaneous return fluctuations. We test both Gaussian and q-Gaussian noise as a source of the short term fluctuations. The resulting model of the return in the financial markets with the same set of parameters reproduces empirical probability and spectral densities of absolute return observed in New York, Warsaw and NASDAQ OMX Vilnius Stock Exchanges. Our result confirms the prevalent idea in behavioral finance that herding interactions may be dominant over agent rationality and contribute towards bubble formation.

  7. Consentaneous agent-based and stochastic model of the financial markets.

    Directory of Open Access Journals (Sweden)

    Vygintas Gontis

    Full Text Available We are looking for the agent-based treatment of the financial markets considering necessity to build bridges between microscopic, agent based, and macroscopic, phenomenological modeling. The acknowledgment that agent-based modeling framework, which may provide qualitative and quantitative understanding of the financial markets, is very ambiguous emphasizes the exceptional value of well defined analytically tractable agent systems. Herding as one of the behavior peculiarities considered in the behavioral finance is the main property of the agent interactions we deal with in this contribution. Looking for the consentaneous agent-based and macroscopic approach we combine two origins of the noise: exogenous one, related to the information flow, and endogenous one, arising form the complex stochastic dynamics of agents. As a result we propose a three state agent-based herding model of the financial markets. From this agent-based model we derive a set of stochastic differential equations, which describes underlying macroscopic dynamics of agent population and log price in the financial markets. The obtained solution is then subjected to the exogenous noise, which shapes instantaneous return fluctuations. We test both Gaussian and q-Gaussian noise as a source of the short term fluctuations. The resulting model of the return in the financial markets with the same set of parameters reproduces empirical probability and spectral densities of absolute return observed in New York, Warsaw and NASDAQ OMX Vilnius Stock Exchanges. Our result confirms the prevalent idea in behavioral finance that herding interactions may be dominant over agent rationality and contribute towards bubble formation.

  8. Lapse of time effects on tax evasion in an agent-based econophysics model

    Science.gov (United States)

    Seibold, Götz; Pickhardt, Michael

    2013-05-01

    We investigate an inhomogeneous Ising model in the context of tax evasion dynamics where different types of agents are parameterized via local temperatures and magnetic fields. In particular, we analyze the impact of lapse of time effects (i.e. backauditing) and endogenously determined penalty rates on tax compliance. Both features contribute to a microfoundation of agent-based econophysics models of tax evasion.

  9. On the role of backauditing for tax evasion in an agent-based Econophysics model

    CERN Document Server

    Seibold, G

    2012-01-01

    We investigate an inhomogeneous Ising model in the context of tax evasion dynamics where different types of agents are parametrized via local temperatures and magnetic fields. In particular, we analyse the impact of backauditing and endogenously determined penalty rates on tax compliance. Both features contribute to a microfoundation of agent-based econophysics models of tax evasion.

  10. Evaluating Urban Parking Policies with Agent-Based Model of Driver Parking Behavior

    NARCIS (Netherlands)

    Martens, C.J.C.M.; Benenson, I.

    2008-01-01

    This paper presents an explicit agent-based model of parking search in a city. In the model, “drivers” drive toward their destination, search for parking, park, remain at the parking place, and leave. The city’s infrastructure is represented by a high-resolution geographic information system (GIS) o

  11. PARKAGENT: An agent-based model of parking in the city

    NARCIS (Netherlands)

    Benenson, I.; Martens, C.J.C.M.; Birfir, S.

    2008-01-01

    In this paper, we present PARKAGENT, an agent-based, spatially explicit model for parking in the city. Unlike traditional parking models, PARKAGENT simulates the behavior of each driver in a spatially explicit environment and is able to capture the complex self-organizing dynamics of a large collect

  12. Land-use change arising from rural land exchange : an agent-based simulation model

    NARCIS (Netherlands)

    Bakker, Martha M.; Alam, Shah Jamal; van Dijk, Jerry; Rounsevell, Mark D. A.

    2015-01-01

    Land exchange can be a major factor driving land-use change in regions with high pressure on land, but is generally not incorporated in land-use change models. Here we present an agent-based model to simulate land-use change arising from land exchange between multiple agent types representing farmer

  13. Decision-Making in Agent-Based Models of Migration: State of the Art and Challenges

    NARCIS (Netherlands)

    Klabunde, A.; Willekens, F.J.

    2016-01-01

    We review agent-based models (ABM) of human migration with respect to their decision-making rules. The most prominent behavioural theories used as decision rules are the random utility theory, as implemented in the discrete choice model, and the theory of planned behaviour. We identify the critical

  14. The Agent-based Model on Real-time Data Warehousing

    Institute of Scientific and Technical Information of China (English)

    YouzhiXu; JieShen

    2004-01-01

    The conventional data warehouse can only analyze historical data. This paper proposes a concept of agent-based real-time data warehouse in BI system, With this model we can improve the real-time performance of data warehouse. On the other hand, the BI system flexibility is enhanced in this model, which makes it much more efficient to manage the distributed environment.

  15. Understanding Group/Party Affiliation Using Social Networks and Agent-Based Modeling

    Science.gov (United States)

    Campbell, Kenyth

    2012-01-01

    The dynamics of group affiliation and group dispersion is a concept that is most often studied in order for political candidates to better understand the most efficient way to conduct their campaigns. While political campaigning in the United States is a very hot topic that most politicians analyze and study, the concept of group/party affiliation presents its own area of study that producers very interesting results. One tool for examining party affiliation on a large scale is agent-based modeling (ABM), a paradigm in the modeling and simulation (M&S) field perfectly suited for aggregating individual behaviors to observe large swaths of a population. For this study agent based modeling was used in order to look at a community of agents and determine what factors can affect the group/party affiliation patterns that are present. In the agent-based model that was used for this experiment many factors were present but two main factors were used to determine the results. The results of this study show that it is possible to use agent-based modeling to explore group/party affiliation and construct a model that can mimic real world events. More importantly, the model in the study allows for the results found in a smaller community to be translated into larger experiments to determine if the results will remain present on a much larger scale.

  16. Agent-Based Game Theory Modeling for Driverless Vehicles at Intersections

    OpenAIRE

    Rakha, Hesham A.; Zohdy, Ismail; Kamalanathsharma, Raj K.

    2013-01-01

    This report presents three research efforts that were published in various journals. The first research effort presents a reactive-driving agent based algorithm for modeling driver left turn gap acceptance behavior at signalized intersections. This model considers the interaction between driver characteristics and vehicle physical capabilities. The model explicitly captures the vehicle constraints on driving behavior using a vehicle dynamics model. In addition, the model uses the driver's inp...

  17. The knowledge management arena: agent-based modelling of the pig sector

    NARCIS (Netherlands)

    Osinga, S.A.

    2015-01-01

    Abstract belonging to PhD thesis:
    The knowledge management arena: agent-based modelling of the pig sector
    Sjoukje A. Osinga
    Wageningen University, Information technology group To be defended on 22nd of April, 2015
    Promotor: Em. Prof. ir AJM (Adrie) Beulens, I

  18. A study of the diffusion of alternative fuel vehicles : An agent-based modeling approach

    NARCIS (Netherlands)

    Zhang, Ting; Gensler, Sonja; Garcia, Rosanna

    2011-01-01

    This paper demonstrates the use of an agent-based model (ABM) to investigate factors that can speed the diffusion of eco-innovations, namely alternative fuel vehicles (AFVs). The ABM provides the opportunity to consider the interdependencies inherent between key participants in the automotive indust

  19. Numerical Problems and Agent-Based Models for a Mass Transfer Course

    Science.gov (United States)

    Murthi, Manohar; Shea, Lonnie D.; Snurr, Randall Q.

    2009-01-01

    Problems requiring numerical solutions of differential equations or the use of agent-based modeling are presented for use in a course on mass transfer. These problems were solved using the popular technical computing language MATLABTM. Students were introduced to MATLAB via a problem with an analytical solution. A more complex problem to which no…

  20. Pattern-oriented modeling of agent-based complex systems: lessons from ecology

    NARCIS (Netherlands)

    Grimm, V.; Revilla, E.; Berger, U.; Jeltsch, F.; Mooij, W.M.; Railsback, S.F.; Thulke, H-H.; Weiner, J.; Wiegand, T.; DeAngelis, D.L.

    2005-01-01

    Agent-based complex systems are dynamic networks of many interacting agents; examples include ecosystems, financial markets, and cities. The search for general principles underlying the internal organization of such systems often uses bottom-up simulation models such as cellular automata and agent-b

  1. Easing the adoption of agent-based modelling (ABM) in tourism research

    NARCIS (Netherlands)

    Johnson, Peter; Nicholls, Sarah; Student, Jillian; Amelung, Bas; Baggio, Rodolfo; Balbi, Stefano; Boavida-Portugal, Ines; Jong, de Eline; Hofstede, G.J.; Lamers, M.A.J.; Pons, Marc; Steiger, Robert

    2016-01-01

    Agent-based modelling (ABM) is an emerging approach in tourism research. Despite the natural fit between theories of tourism as a complex, interconnected system, and the generative approach supported in ABM, there has been only limited integration within mainstream tourism research. This research le

  2. Targeting and timing promotional activities : An agent-based model for the takeoff of new products

    NARCIS (Netherlands)

    Delre, S. A.; Jager, W.; Bijmolt, T. H. A.; Janssen, M. A.

    2007-01-01

    Many marketing efforts focus on promotional activities that support the launch of new products. Promotional strategies may play a crucial role in the early stages of the product life cycle, and determine to a large extent the diffusion of a new product. This paper proposes an agent-based model to si

  3. Agent-Based Modeling of Consumer Decision making Process Based on Power Distance and Personality

    NARCIS (Netherlands)

    Roozmand, O.; Ghasem-Aghaee, N.; Hofstede, G.J.; Nematbakhsh, M.A.; Baraani, A.; Verwaart, T.

    2011-01-01

    Simulating consumer decision making processes involves different disciplines such as: sociology, social psychology, marketing, and computer science. In this paper, we propose an agent-based conceptual and computational model of consumer decision-making based on culture, personality and human needs.

  4. Learning Natural Selection in 4th Grade with Multi-Agent-Based Computational Models

    Science.gov (United States)

    Dickes, Amanda Catherine; Sengupta, Pratim

    2013-01-01

    In this paper, we investigate how elementary school students develop multi-level explanations of population dynamics in a simple predator-prey ecosystem, through scaffolded interactions with a multi-agent-based computational model (MABM). The term "agent" in an MABM indicates individual computational objects or actors (e.g., cars), and these…

  5. Questioning the quantity equation using an agent-based computational model

    DEFF Research Database (Denmark)

    Bruun, Charlotte

    2000-01-01

    by Stutzel (1954), argues that the functional relationship may as well be negative. Even focusing the money needed to carry out transactions, there is no immediate answer to the question of the functional relationship between trade turnover and money demand. An agent-based computational model is used...

  6. Agent-Based Modeling and Simulation of Child Maltreatment and Child Maltreatment Prevention

    OpenAIRE

    Xiaolin Hu; Nicholas Keller

    2015-01-01

    This paper presents an agent-based model that simulates the dynamics of child maltreatment and child maltreatment prevention. The developed model follows the principles of complex systems science and explicitly models a community and its families with multi-level factors across the social ecology. Each agent includes behavioral/cognitive modeling to account for the behavioral/cognitive process of child maltreatment. Simulation of child maltreatment prevention is also supported to evaluate the...

  7. High performance computing for three-dimensional agent-based molecular models.

    Science.gov (United States)

    Pérez-Rodríguez, G; Pérez-Pérez, M; Fdez-Riverola, F; Lourenço, A

    2016-07-01

    Agent-based simulations are increasingly popular in exploring and understanding cellular systems, but the natural complexity of these systems and the desire to grasp different modelling levels demand cost-effective simulation strategies and tools. In this context, the present paper introduces novel sequential and distributed approaches for the three-dimensional agent-based simulation of individual molecules in cellular events. These approaches are able to describe the dimensions and position of the molecules with high accuracy and thus, study the critical effect of spatial distribution on cellular events. Moreover, two of the approaches allow multi-thread high performance simulations, distributing the three-dimensional model in a platform independent and computationally efficient way. Evaluation addressed the reproduction of molecular scenarios and different scalability aspects of agent creation and agent interaction. The three approaches simulate common biophysical and biochemical laws faithfully. The distributed approaches show improved performance when dealing with large agent populations while the sequential approach is better suited for small to medium size agent populations. Overall, the main new contribution of the approaches is the ability to simulate three-dimensional agent-based models at the molecular level with reduced implementation effort and moderate-level computational capacity. Since these approaches have a generic design, they have the major potential of being used in any event-driven agent-based tool.

  8. High performance computing for three-dimensional agent-based molecular models.

    Science.gov (United States)

    Pérez-Rodríguez, G; Pérez-Pérez, M; Fdez-Riverola, F; Lourenço, A

    2016-07-01

    Agent-based simulations are increasingly popular in exploring and understanding cellular systems, but the natural complexity of these systems and the desire to grasp different modelling levels demand cost-effective simulation strategies and tools. In this context, the present paper introduces novel sequential and distributed approaches for the three-dimensional agent-based simulation of individual molecules in cellular events. These approaches are able to describe the dimensions and position of the molecules with high accuracy and thus, study the critical effect of spatial distribution on cellular events. Moreover, two of the approaches allow multi-thread high performance simulations, distributing the three-dimensional model in a platform independent and computationally efficient way. Evaluation addressed the reproduction of molecular scenarios and different scalability aspects of agent creation and agent interaction. The three approaches simulate common biophysical and biochemical laws faithfully. The distributed approaches show improved performance when dealing with large agent populations while the sequential approach is better suited for small to medium size agent populations. Overall, the main new contribution of the approaches is the ability to simulate three-dimensional agent-based models at the molecular level with reduced implementation effort and moderate-level computational capacity. Since these approaches have a generic design, they have the major potential of being used in any event-driven agent-based tool. PMID:27372059

  9. Investigating Output Accuracy for a Discrete Event Simulation Model and an Agent Based Simulation Model

    CERN Document Server

    Majid, Mazlina Abdul; Siebers, Peer-Olaf

    2010-01-01

    In this paper, we investigate output accuracy for a Discrete Event Simulation (DES) model and Agent Based Simulation (ABS) model. The purpose of this investigation is to find out which of these simulation techniques is the best one for modelling human reactive behaviour in the retail sector. In order to study the output accuracy in both models, we have carried out a validation experiment in which we compared the results from our simulation models to the performance of a real system. Our experiment was carried out using a large UK department store as a case study. We had to determine an efficient implementation of management policy in the store's fitting room using DES and ABS. Overall, we have found that both simulation models were a good representation of the real system when modelling human reactive behaviour.

  10. Empirically Grounded Agent-Based Models of Innovation Diffusion: A Critical Review

    CERN Document Server

    Zhang, Haifeng

    2016-01-01

    Innovation diffusion has been studied extensively in a variety of disciplines, including sociology, economics, marketing, ecology, and computer science. Traditional literature on innovation diffusion has been dominated by models of aggregate behavior and trends. However, the agent-based modeling (ABM) paradigm is gaining popularity as it captures agent heterogeneity and enables fine-grained modeling of interactions mediated by social and geographic networks. While most ABM work on innovation diffusion is theoretical, empirically grounded models are increasingly important, particularly in guiding policy decisions. We present a critical review of empirically grounded agent-based models of innovation diffusion, developing a categorization of this research based on types of agent models as well as applications. By connecting the modeling methodologies in the fields of information and innovation diffusion, we suggest that the maximum likelihood estimation framework widely used in the former is a promising paradigm...

  11. Modeling the Information Age Combat Model: An Agent-Based Simulation of Network Centric Operations

    Science.gov (United States)

    Deller, Sean; Rabadi, Ghaith A.; Bell, Michael I.; Bowling, Shannon R.; Tolk, Andreas

    2010-01-01

    The Information Age Combat Model (IACM) was introduced by Cares in 2005 to contribute to the development of an understanding of the influence of connectivity on force effectiveness that can eventually lead to quantitative prediction and guidelines for design and employment. The structure of the IACM makes it clear that the Perron-Frobenius Eigenvalue is a quantifiable metric with which to measure the organization of a networked force. The results of recent experiments presented in Deller, et aI., (2009) indicate that the value of the Perron-Frobenius Eigenvalue is a significant measurement of the performance of an Information Age combat force. This was accomplished through the innovative use of an agent-based simulation to model the IACM and represents an initial contribution towards a new generation of combat models that are net-centric instead of using the current platform-centric approach. This paper describes the intent, challenges, design, and initial results of this agent-based simulation model.

  12. Agent-based modeling of malaria vectors: the importance of spatial simulation

    OpenAIRE

    Bomblies, Arne

    2014-01-01

    Background The modeling of malaria vector mosquito populations yields great insight into drivers of malaria transmission at the village scale. Simulation of individual mosquitoes as “agents” in a distributed, dynamic model domain may be greatly beneficial for simulation of spatial relationships of vectors and hosts. Methods In this study, an agent-based model is used to simulate the life cycle and movement of individual malaria vector mosquitoes in a Niger Sahel village, with individual simul...

  13. Agent-based model for rural-urban migration: A dynamic consideration

    Science.gov (United States)

    Cai, Ning; Ma, Hai-Ying; Khan, M. Junaid

    2015-10-01

    This paper develops a dynamic agent-based model for rural-urban migration, based on the previous relevant works. The model conforms to the typical dynamic linear multi-agent systems model concerned extensively in systems science, in which the communication network is formulated as a digraph. Simulations reveal that consensus of certain variable could be harmful to the overall stability and should be avoided.

  14. An Agent-Based Model of New Venture Creation: Conceptual Design for Simulating Entrepreneurship

    Science.gov (United States)

    Provance, Mike; Collins, Andrew; Carayannis, Elias

    2012-01-01

    There is a growing debate over the means by which regions can foster the growth of entrepreneurial activity in order to stimulate recovery and growth of their economies. On one side, agglomeration theory suggests the regions grow because of strong clusters that foster knowledge spillover locally; on the other side, the entrepreneurial action camp argues that innovative business models are generated by entrepreneurs with unique market perspectives who draw on knowledge from more distant domains. We will show you the design for a novel agent-based model of new venture creation that will demonstrate the relationship between agglomeration and action. The primary focus of this model is information exchange as the medium for these agent interactions. Our modeling and simulation study proposes to reveal interesting relationships in these perspectives, offer a foundation on which these disparate theories from economics and sociology can find common ground, and expand the use of agent-based modeling into entrepreneurship research.

  15. Architectural considerations for agent-based national scale policy models : LDRD final report.

    Energy Technology Data Exchange (ETDEWEB)

    Backus, George A.; Strip, David R.

    2007-09-01

    The need to anticipate the consequences of policy decisions becomes ever more important as the magnitude of the potential consequences grows. The multiplicity of connections between the components of society and the economy makes intuitive assessments extremely unreliable. Agent-based modeling has the potential to be a powerful tool in modeling policy impacts. The direct mapping between agents and elements of society and the economy simplify the mapping of real world functions into the world of computation assessment. Our modeling initiative is motivated by the desire to facilitate informed public debate on alternative policies for how we, as a nation, provide healthcare to our population. We explore the implications of this motivation on the design and implementation of a model. We discuss the choice of an agent-based modeling approach and contrast it to micro-simulation and systems dynamics approaches.

  16. Agent-Based Modeling of Harvest Decisions by Small Scale Forest Landowners in Maine, USA

    Directory of Open Access Journals (Sweden)

    Jessica E. Leahy

    2013-01-01

    Full Text Available Small-scale forests are an excellent example of coupled social-ecological systems, which involve human and biophysical subsystems with complex two-way feedback interactions. The multifaceted nature of landowner decisions drives a significant need to better understand decision-making processes, reactions to policy, and combined impacts on ecosystems in a comprehensive manner. Small-scale forests require an integrated approach to modeling the social and biophysical components comprehensively. Agent-based modeling involves modeling individualistic behavior and interpreting patterns that emerge. The interaction between agents and their environments makes this a valuable tool to assess repeated decisions of individual landowners responding to changing environmental conditions. Agent-based models can be used to determine potential ecological, economic, and social outcomes of landowner decisions and reactions to changing conditions. A forest landowner agent-based model experiment was developed to model timber harvesting in Maine, USA. We present baseline simulation results and compare the effect of a social change (an increased tax rate and a biophysical change (a pest outbreak resulting in increased tree mortality on the system. These three scenarios were analyzed using ANOVA and MANOVA tests on harvested hectares and landowner goal scores to assess landowner behavior and priorities by action. We conclude by reviewing implications for future modeling efforts.

  17. An Evolutionary Agent-based simulation model for the industry life cycle

    OpenAIRE

    Lehmann-Waffenschmidt, B. Cornelia

    2008-01-01

    In contrast to the usual approach taken in the literature, in which an Industry Life Cycle (ILC) is reproduced by aggregate functions, the model of this paper generates a self-organizing ILC. A general evolutionary agent-based simulation model is developed that can be adapted for specific branches of industry. The results enable conclusions to be drawn for competition policy with regard to the workability of competition in the various phases of the ILC.

  18. Asking the Oracle: Introducing Forecasting Principles into Agent-Based Modelling

    OpenAIRE

    Hassan, Samer; Arroyo, Javier; Galán Ordax, José Manuel; Antunes, Luis; Pavón Mestras, Juan

    2013-01-01

    This paper presents a set of guidelines, imported from the field of forecasting, that can help social simulation and, more specifically, agent-based modelling practitioners to improve the predictive performance and the robustness of their models. The presentation starts with a discussion on the current debate on prediction in social processes, followed by an overview of the recent experience and lessons learnt from the field of forecasting. This is the basis to define standard practices when ...

  19. Electricity Market Games: How Agent-Based Modeling Can Help under High Penetrations of Variable Generation

    Energy Technology Data Exchange (ETDEWEB)

    Gallo, Giulia

    2016-03-01

    Integrating increasingly high levels of variable generation in U.S. electricity markets requires addressing not only power system and grid modeling challenges but also an understanding of how market participants react and adapt to them. Key elements of current and future wholesale power markets can be modeled using an agent-based approach, which may prove to be a useful paradigm for researchers studying and planning for power systems of the future.

  20. Agent-based model with asymmetric trading and herding for complex financial systems

    OpenAIRE

    Jun-Jie Chen; Bo Zheng; Lei Tan

    2014-01-01

    BACKGROUND: For complex financial systems, the negative and positive return-volatility correlations, i.e., the so-called leverage and anti-leverage effects, are particularly important for the understanding of the price dynamics. However, the microscopic origination of the leverage and anti-leverage effects is still not understood, and how to produce these effects in agent-based modeling remains open. On the other hand, in constructing microscopic models, it is a promising conception to determ...

  1. Landscape Epidemiology Modeling Using an Agent-Based Model and a Geographic Information System

    Directory of Open Access Journals (Sweden)

    S. M. Niaz Arifin

    2015-05-01

    Full Text Available A landscape epidemiology modeling framework is presented which integrates the simulation outputs from an established spatial agent-based model (ABM of malaria with a geographic information system (GIS. For a study area in Kenya, five landscape scenarios are constructed with varying coverage levels of two mosquito-control interventions. For each scenario, maps are presented to show the average distributions of three output indices obtained from the results of 750 simulation runs. Hot spot analysis is performed to detect statistically significant hot spots and cold spots. Additional spatial analysis is conducted using ordinary kriging with circular semivariograms for all scenarios. The integration of epidemiological simulation-based results with spatial analyses techniques within a single modeling framework can be a valuable tool for conducting a variety of disease control activities such as exploring new biological insights, monitoring epidemiological landscape changes, and guiding resource allocation for further investigation.

  2. Agent-based simulation of building evacuation using a grid graph-based model

    Science.gov (United States)

    Tan, L.; Lin, H.; Hu, M.; Che, W.

    2014-02-01

    Shifting from macroscope models to microscope models, the agent-based approach has been widely used to model crowd evacuation as more attentions are paid on individualized behaviour. Since indoor evacuation behaviour is closely related to spatial features of the building, effective representation of indoor space is essential for the simulation of building evacuation. The traditional cell-based representation has limitations in reflecting spatial structure and is not suitable for topology analysis. Aiming at incorporating powerful topology analysis functions of GIS to facilitate agent-based simulation of building evacuation, we used a grid graph-based model in this study to represent the indoor space. Such model allows us to establish an evacuation network at a micro level. Potential escape routes from each node thus could be analysed through GIS functions of network analysis considering both the spatial structure and route capacity. This would better support agent-based modelling of evacuees' behaviour including route choice and local movements. As a case study, we conducted a simulation of emergency evacuation from the second floor of an official building using Agent Analyst as the simulation platform. The results demonstrate the feasibility of the proposed method, as well as the potential of GIS in visualizing and analysing simulation results.

  3. Agent-based simulation of building evacuation using a grid graph-based model

    International Nuclear Information System (INIS)

    Shifting from macroscope models to microscope models, the agent-based approach has been widely used to model crowd evacuation as more attentions are paid on individualized behaviour. Since indoor evacuation behaviour is closely related to spatial features of the building, effective representation of indoor space is essential for the simulation of building evacuation. The traditional cell-based representation has limitations in reflecting spatial structure and is not suitable for topology analysis. Aiming at incorporating powerful topology analysis functions of GIS to facilitate agent-based simulation of building evacuation, we used a grid graph-based model in this study to represent the indoor space. Such model allows us to establish an evacuation network at a micro level. Potential escape routes from each node thus could be analysed through GIS functions of network analysis considering both the spatial structure and route capacity. This would better support agent-based modelling of evacuees' behaviour including route choice and local movements. As a case study, we conducted a simulation of emergency evacuation from the second floor of an official building using Agent Analyst as the simulation platform. The results demonstrate the feasibility of the proposed method, as well as the potential of GIS in visualizing and analysing simulation results

  4. Graceful Failure and Societal Resilience Analysis Via Agent-Based Modeling and Simulation

    Science.gov (United States)

    Schopf, P. S.; Cioffi-Revilla, C.; Rogers, J. D.; Bassett, J.; Hailegiorgis, A. B.

    2014-12-01

    Agent-based social modeling is opening up new methodologies for the study of societal response to weather and climate hazards, and providing measures of resiliency that can be studied in many contexts, particularly in coupled human and natural-technological systems (CHANTS). Since CHANTS are complex adaptive systems, societal resiliency may or may not occur, depending on dynamics that lack closed form solutions. Agent-based modeling has been shown to provide a viable theoretical and methodological approach for analyzing and understanding disasters and societal resiliency in CHANTS. Our approach advances the science of societal resilience through computational modeling and simulation methods that complement earlier statistical and mathematical approaches. We present three case studies of social dynamics modeling that demonstrate the use of these agent based models. In Central Asia, we exmaine mutltiple ensemble simulations with varying climate statistics to see how droughts and zuds affect populations, transmission of wealth across generations, and the overall structure of the social system. In Eastern Africa, we explore how successive episodes of drought events affect the adaptive capacity of rural households. Human displacement, mainly, rural to urban migration, and livelihood transition particularly from pastoral to farming are observed as rural households interacting dynamically with the biophysical environment and continually adjust their behavior to accommodate changes in climate. In the far north case we demonstrate one of the first successful attempts to model the complete climate-permafrost-infrastructure-societal interaction network as a complex adaptive system/CHANTS implemented as a ``federated'' agent-based model using evolutionary computation. Analysis of population changes resulting from extreme weather across these and other cases provides evidence for the emergence of new steady states and shifting patterns of resilience.

  5. Quantitative agent based model of user behavior in an Internet discussion forum.

    Directory of Open Access Journals (Sweden)

    Pawel Sobkowicz

    Full Text Available The paper presents an agent based simulation of opinion evolution, based on a nonlinear emotion/information/opinion (E/I/O individual dynamics, to an actual Internet discussion forum. The goal is to reproduce the results of two-year long observations and analyses of the user communication behavior and of the expressed opinions and emotions, via simulations using an agent based model. The model allowed to derive various characteristics of the forum, including the distribution of user activity and popularity (outdegree and indegree, the distribution of length of dialogs between the participants, their political sympathies and the emotional content and purpose of the comments. The parameters used in the model have intuitive meanings, and can be translated into psychological observables.

  6. Quantitative agent based model of user behavior in an Internet discussion forum.

    Science.gov (United States)

    Sobkowicz, Pawel

    2013-01-01

    The paper presents an agent based simulation of opinion evolution, based on a nonlinear emotion/information/opinion (E/I/O) individual dynamics, to an actual Internet discussion forum. The goal is to reproduce the results of two-year long observations and analyses of the user communication behavior and of the expressed opinions and emotions, via simulations using an agent based model. The model allowed to derive various characteristics of the forum, including the distribution of user activity and popularity (outdegree and indegree), the distribution of length of dialogs between the participants, their political sympathies and the emotional content and purpose of the comments. The parameters used in the model have intuitive meanings, and can be translated into psychological observables.

  7. A critical survey of agent-based wholesale electricity market models

    Energy Technology Data Exchange (ETDEWEB)

    Weidlich, Anke; Veit, Daniel [University of Mannheim, Chair of Business Administration and Information Systems, Schloss, 68131 Mannheim (Germany)

    2008-07-15

    The complexity of electricity markets calls for rich and flexible modeling techniques that help to understand market dynamics and to derive advice for the design of appropriate regulatory frameworks. Agent-Based Computational Economics (ACE) is a fairly young research paradigm that offers methods for realistic electricity market modeling. A growing number of researchers have developed agent-based models for simulating electricity markets. The diversity of approaches makes it difficult to overview the field of ACE electricity research; this literature survey should guide the way through and describe the state-of-the-art of this research area. In a conclusive summary, shortcomings of existing approaches and open issues that should be addressed by ACE electricity researchers are critically discussed. (author)

  8. Pain expressiveness and altruistic behavior: an exploration using agent-based modeling.

    Science.gov (United States)

    de C Williams, Amanda C; Gallagher, Elizabeth; Fidalgo, Antonio R; Bentley, Peter J

    2016-03-01

    Predictions which invoke evolutionary mechanisms are hard to test. Agent-based modeling in artificial life offers a way to simulate behaviors and interactions in specific physical or social environments over many generations. The outcomes have implications for understanding adaptive value of behaviors in context. Pain-related behavior in animals is communicated to other animals that might protect or help, or might exploit or predate. An agent-based model simulated the effects of displaying or not displaying pain (expresser/nonexpresser strategies) when injured and of helping, ignoring, or exploiting another in pain (altruistic/nonaltruistic/selfish strategies). Agents modeled in MATLAB interacted at random while foraging (gaining energy); random injury interrupted foraging for a fixed time unless help from an altruistic agent, who paid an energy cost, speeded recovery. Environmental and social conditions also varied, and each model ran for 10,000 iterations. Findings were meaningful in that, in general, contingencies that evident from experimental work with a variety of mammals, over a few interactions, were replicated in the agent-based model after selection pressure over many generations. More energy-demanding expression of pain reduced its frequency in successive generations, and increasing injury frequency resulted in fewer expressers and altruists. Allowing exploitation of injured agents decreased expression of pain to near zero, but altruists remained. Decreasing costs or increasing benefits of helping hardly changed its frequency, whereas increasing interaction rate between injured agents and helpers diminished the benefits to both. Agent-based modeling allows simulation of complex behaviors and environmental pressures over evolutionary time. PMID:26655734

  9. Excellent approach to modeling urban expansion by fuzzy cellular automata: agent base model

    Science.gov (United States)

    Khajavigodellou, Yousef; Alesheikh, Ali A.; Mohammed, Abdulrazak A. S.; Chapi, Kamran

    2014-09-01

    Recently, the interaction between humans and their environment is the one of important challenges in the world. Landuse/ cover change (LUCC) is a complex process that includes actors and factors at different social and spatial levels. The complexity and dynamics of urban systems make the applicable practice of urban modeling very difficult. With the increased computational power and the greater availability of spatial data, micro-simulation such as the agent based and cellular automata simulation methods, has been developed by geographers, planners, and scholars, and it has shown great potential for representing and simulating the complexity of the dynamic processes involved in urban growth and land use change. This paper presents Fuzzy Cellular Automata in Geospatial Information System and remote Sensing to simulated and predicted urban expansion pattern. These FCA-based dynamic spatial urban models provide an improved ability to forecast and assess future urban growth and to create planning scenarios, allowing us to explore the potential impacts of simulations that correspond to urban planning and management policies. A fuzzy inference guided cellular automata approach. Semantic or linguistic knowledge on Land use change is expressed as fuzzy rules, based on which fuzzy inference is applied to determine the urban development potential for each pixel. The model integrates an ABM (agent-based model) and FCA (Fuzzy Cellular Automata) to investigate a complex decision-making process and future urban dynamic processes. Based on this model rapid development and green land protection under the influences of the behaviors and decision modes of regional authority agents, real estate developer agents, resident agents and non- resident agents and their interactions have been applied to predict the future development patterns of the Erbil metropolitan region.

  10. An Agent-Based Modeling Template for a Cohort of Veterans with Diabetic Retinopathy.

    Directory of Open Access Journals (Sweden)

    Theodore Eugene Day

    Full Text Available Agent-based models are valuable for examining systems where large numbers of discrete individuals interact with each other, or with some environment. Diabetic Veterans seeking eye care at a Veterans Administration hospital represent one such cohort.The objective of this study was to develop an agent-based template to be used as a model for a patient with diabetic retinopathy (DR. This template may be replicated arbitrarily many times in order to generate a large cohort which is representative of a real-world population, upon which in-silico experimentation may be conducted.Agent-based template development was performed in java-based computer simulation suite AnyLogic Professional 6.6. The model was informed by medical data abstracted from 535 patient records representing a retrospective cohort of current patients of the VA St. Louis Healthcare System Eye clinic. Logistic regression was performed to determine the predictors associated with advancing stages of DR. Predicted probabilities obtained from logistic regression were used to generate the stage of DR in the simulated cohort.The simulated cohort of DR patients exhibited no significant deviation from the test population of real-world patients in proportion of stage of DR, duration of diabetes mellitus (DM, or the other abstracted predictors. Simulated patients after 10 years were significantly more likely to exhibit proliferative DR (P<0.001.Agent-based modeling is an emerging platform, capable of simulating large cohorts of individuals based on manageable data abstraction efforts. The modeling method described may be useful in simulating many different conditions where course of disease is described in categorical stages.

  11. Simulating GenCo bidding strategies in electricity markets with an agent-based model

    International Nuclear Information System (INIS)

    In this paper we use an agent-based simulation model, EMCAS, to analyze market power in electricity markets. We focus on the effect of congestion management on the ability of generating companies (GenCos) to raise prices beyond competitive levels. An 11-node test power system is used to compare a market design based on locational marginal pricing with a market design that uses system marginal pricing and congestion management by counter trading. Bidding strategies based on both physical and economic withholding are compared to a base case with production cost bidding. The results show that unilateral market power is exercised under both pricing mechanisms. However, the largest changes in consumer costs and GenCo profits due to strategic bidding occur under the locational marginal pricing scheme. The analysis also illustrates that agent-based modeling can contribute important insights into the complex interactions between the participants in transmission-constrained electricity markets. (Author)

  12. Mobile Agent-Based Software Systems Modeling Approaches: A Comparative Study

    Directory of Open Access Journals (Sweden)

    Aissam Belghiat

    2016-06-01

    Full Text Available Mobile agent-based applications are special type of software systems which take the advantages of mobile agents in order to provide a new beneficial paradigm to solve multiple complex problems in several fields and areas such as network management, e-commerce, e-learning, etc. Likewise, we notice lack of real applications based on this paradigm and lack of serious evaluations of their modeling approaches. Hence, this paper provides a comparative study of modeling approaches of mobile agent-based software systems. The objective is to give the reader an overview and a thorough understanding of the work that has been done and where the gaps in the research are.

  13. Agent-based Models in Synthetic Biology: Tools for Simulation and Prospects

    Directory of Open Access Journals (Sweden)

    E.V.Krishnamurthy

    2012-03-01

    Full Text Available We describe a multiset of agents based modeling and simulation paradigm for synthetic biology. The multiset of agents –based programming paradigm, can be interpreted as the outcome arising out of deterministic, nondeterministic or stochastic interaction among elements in a multiset object space, that includes the environment. These interactions are like chemical reactions and the evolution of the multiset can emulate the system biological functions. Since the reaction rules are inherently parallel, any number of actions can be performed cooperatively or competitively among the subsets of elements, so that the elements evolve toward equilibrium or emergent state. Practical realization of this paradigm for system biological simulation is achieved through the concept of transactional style programming with agents, as well as soft computing (neural- network principles. Also we briefly describe currently available tools for agent-based-modeling, simulation and animation.

  14. Agent-based and macroscopic modeling of the complex socio-economic systems

    CERN Document Server

    Kononovicius, Aleksejus

    2013-01-01

    The current economic crisis has provoked an active response from the interdisciplinary scientific community. As a result many papers suggesting what can be improved in understanding of the complex socio-economics systems were published. Some of the most prominent papers on the topic include (Bouchaud, 2009; Farmer and Foley, 2009; Farmer et al, 2012; Helbing, 2010; Pietronero, 2008). These papers share the idea that agent-based modeling is essential for the better understanding of the complex socio-economic systems and consequently better policy making. Yet in order for an agent-based model to be useful it should also be analytically tractable, possess a macroscopic treatment (Cristelli et al, 2012). In this work we shed a new light on our research group's contributions towards understanding of the correspondence between the inter-individual interactions and collective behavior. We also provide some new insights into the implications of the global and local interactions, the leadership and the predator-prey i...

  15. An Agent Operationalization Approach for Context Specific Agent-Based Modeling

    OpenAIRE

    Christof Knoeri; Binder, Claudia R.; Hans-Joerg Althaus

    2011-01-01

    The potential of agent-based modeling (ABM) has been demonstrated in various research fields. However, three major concerns limit the full exploitation of ABM; (i) agents are too simple and behave unrealistically without any empirical basis, (ii) 'proof of concept' applications are too theoretical and (iii) too much value placed on operational validity instead of conceptual validity. This paper presents an operationalization approach to determine the key system agents, their interaction, deci...

  16. Encouraging Sustainable Transport Choices in American Households: Results from an Empirically Grounded Agent-Based Model

    OpenAIRE

    Davide Natalini; Giangiacomo Bravo

    2013-01-01

    The transport sector needs to go through an extended process of decarbonisation to counter the threat of climate change. Unfortunately, the International Energy Agency forecasts an enormous growth in the number of cars and greenhouse gas emissions by 2050. Two issues can thus be identified: (1) the need for a new methodology that could evaluate the policy performances ex-ante and (2) the need for more effective policies. To help address these issues, we developed an Agent-Based Model called ...

  17. Organizational ecology and population dynamics in politics : an agent-based model

    OpenAIRE

    Jung, Danielle Fitzpatrick

    2012-01-01

    Markets, networks and hierarchies are the three core forms of social organization. They recur at all levels of social interaction as solutions to problems of cooperation. Disparate actors---from states, to "dark'' actors like rebel groups, to voters---use these organizations to solve their cooperative problems. This dissertation uses a general agent-based model (ABM) to examine how organizations affect cooperation and welfare across several issues. Humans form organizations to enhance coopera...

  18. An Agent-Based Model of Centralized Institutions, Social Network Technology, and Revolution

    OpenAIRE

    Makowsky, Michael D.; Jared Rubin

    2011-01-01

    Recent uprisings in the Arab world consist of individuals revealing vastly different preferences than were expressed prior to the uprisings. This paper sheds light on the general mechanisms underlying large-scale social and institutional change. We employ an agent-based model to test the impact of authority centralization and social network technology on preference revelation and falsification, social protest, and institutional change. We find that the amount of social and institutional chang...

  19. An Agent-Based Model of Sustainable Corporate Social Responsibility Activities

    OpenAIRE

    Isamu Okada

    2011-01-01

    An agent-based model of firms and their stakeholders' economic actions was used to test the theoretical feasibility of sustainable corporate social responsibility activities. Corporate social responsibility has become important to many firms, but CSR activities tend to get less attention during busts than during boom times. The hypothesis tested is that the CSR activities of a firm are more economically rational if the economic actions of its stakeholders reflect the firm's level of CSR. Our ...

  20. Analyzing the Validity of Relationship Banking through Agent-based Modeling

    Science.gov (United States)

    Nishikido, Yukihito; Takahashi, Hiroshi

    This article analyzes the validity of relationship banking through agent-based modeling. In the analysis, we especially focus on the relationship between economic conditions and both lenders' and borrowers' behaviors. As a result of intensive experiments, we made the following interesting findings: (1) Relationship banking contributes to reducing bad loan; (2) relationship banking is more effective in enhancing the market growth compared to transaction banking, when borrowers' sales scale is large; (3) keener competition among lenders may bring inefficiency to the market.

  1. Evaluating agri-environmental schemes using a spatially explicit agent-based modelling approach

    OpenAIRE

    Schouten, M.A.H.; Polman, N.B.P.; Westerhof, E.J.G.M.; Opdam, P.F.M.

    2012-01-01

    Networks of nature reserves are being proposed as a solution when the degree of fragmentation is considered to endanger the long-term persistence of species diversity. Agri-environmental schemes are supposed to make a positive contribution to these networks. The spatially explicit agent-based model presented in this chapter combines spatial dynamics in land ownership, land use and the importance of agri-environmental schemes in conserving biodiversity by capturing the heterogeneity of individ...

  2. Firms, Innovation, Export and the Policy Regime: An Agent-based model of the Defence Industry

    OpenAIRE

    2011-01-01

    The defence industry has traditionally been a heavily regulated and protected market. A new EU Directive being implemented in Norway, January 2012, intends to reform the European defence market towards a higher degree of openness and liberalization. It is therefore vital for the Norwegian Government and national defence authorities to explore the impacts this new EU Directive will have in the near future. This thesis presents a computational agent-based model of the Norwegian defence industry...

  3. Agent Based Modeling of Land Use Change: The Case of Shade Coffee in Mexico.

    OpenAIRE

    Marcos-Martinez, Raymundo

    2013-01-01

    This research focuses on addressing methodological issues that impact the performance of spatially explicit discrete choice agent-based land use models that are estimated with remotely sensed data. The empirical setting considers land use transitions between agroforests, perennial crops, grass and corn, and fallow lands during the period 1984 - 2006 in a Mexican coffee growing region in which relatively high deforestation rates were observed. As a starting point, a Mixed Conditional - Multino...

  4. Agent-Based Modeling and Genetic Algorithm Simulation for the Climate Game Problem

    OpenAIRE

    Zheng Wang; Jingling Zhang

    2012-01-01

    The cooperative game of global temperature lacks automaticity and emotional jamming. To solve this issue, an agent-based modelling method is developed based on Milinski’s noncooperative game experiments. In addition, genetic algorithm is used to improve the investment strategy of each agent. Simulations are carried out by designing different coding schemes, mutation schemes, and fitness functions. It is demonstrated that the method can achieve maximum benefits under the premise of the agent n...

  5. Simulating Transport and Land Use Interdependencies for Strategic Urban Planning—An Agent Based Modelling Approach

    Directory of Open Access Journals (Sweden)

    Nam Huynh

    2015-10-01

    Full Text Available Agent based modelling has been widely accepted as a promising tool for urban planning purposes thanks to its capability to provide sophisticated insights into the social behaviours and the interdependencies that characterise urban systems. In this paper, we report on an agent based model, called TransMob, which explicitly simulates the mutual dynamics between demographic evolution, transport demands, housing needs and the eventual change in the average satisfaction of the residents of an urban area. The ability to reproduce such dynamics is a unique feature that has not been found in many of the like agent based models in the literature. TransMob, is constituted by six major modules: synthetic population, perceived liveability, travel diary assignment, traffic micro-simulator, residential location choice, and travel mode choice. TransMob is used to simulate the dynamics of a metropolitan area in South East of Sydney, Australia, in 2006 and 2011, with demographic evolution. The results are favourably compared against survey data for the area in 2011, therefore validating the capability of TransMob to reproduce the observed complexity of an urban area. We also report on the application of TransMob to simulate various hypothetical scenarios of urban planning policies. We conclude with discussions on current limitations of TransMob, which serve as suggestions for future developments.

  6. Biomimetic agent based modelling using male Frog calling behaviour as a case study

    DEFF Research Database (Denmark)

    Jørgensen, Søren V.; Demazeau, Yves; Christensen-Dalsgaard, Jakob;

    2014-01-01

    A new agent-based modelling tool has been developed to allow the modelling of populations of individuals whose interactions are characterised by tightly timed dynamics. The tool was developed to model male frog calling dynamics, to facilitate research into what local rules may be employed...... Frog, E. coqui, is implemented as a case study for the presentation and discussion of the tool, and results from this model are presented. RANA, in its present stage of development, is shown to be able to handle the problem of modelling calling frogs, and several fruitful extensions are proposed...

  7. A Novel Application of Agent-based Modeling: Projecting Water Access and Availability Using a Coupled Hydrologic Agent-based Model in the Nzoia Basin, Kenya

    Science.gov (United States)

    Le, A.; Pricope, N. G.

    2015-12-01

    Projections indicate that increasing population density, food production, and urbanization in conjunction with changing climate conditions will place stress on water resource availability. As a result, a holistic understanding of current and future water resource distribution is necessary for creating strategies to identify the most sustainable means of accessing this resource. Currently, most water resource management strategies rely on the application of global climate predictions to physically based hydrologic models to understand potential changes in water availability. However, the need to focus on understanding community-level social behaviors that determine individual water usage is becoming increasingly evident, as predictions derived only from hydrologic models cannot accurately represent the coevolution of basin hydrology and human water and land usage. Models that are better equipped to represent the complexity and heterogeneity of human systems and satellite-derived products in place of or in conjunction with historic data significantly improve preexisting hydrologic model accuracy and application outcomes. We used a novel agent-based sociotechnical model that combines the Soil and Water Assessment Tool (SWAT) and Agent Analyst and applied it in the Nzoia Basin, an area in western Kenya that is becoming rapidly urbanized and industrialized. Informed by a combination of satellite-derived products and over 150 household surveys, the combined sociotechnical model provided unique insight into how populations self-organize and make decisions based on water availability. In addition, the model depicted how population organization and current management alter water availability currently and in the future.

  8. Integrated Agent-Based and Production Cost Modeling Framework for Renewable Energy Studies

    Energy Technology Data Exchange (ETDEWEB)

    Gallo, Giulia

    2016-01-08

    The agent-based framework for renewable energy studies (ARES) is an integrated approach that adds an agent-based model of industry actors to PLEXOS and combines the strengths of the two to overcome their individual shortcomings. It can examine existing and novel wholesale electricity markets under high penetrations of renewables. ARES is demonstrated by studying how increasing levels of wind will impact the operations and the exercise of market power of generation companies that exploit an economic withholding strategy. The analysis is carried out on a test system that represents the Electric Reliability Council of Texas energy-only market in the year 2020. The results more realistically reproduce the operations of an energy market under different and increasing penetrations of wind, and ARES can be extended to address pressing issues in current and future wholesale electricity markets.

  9. Integrated Agent-Based and Production Cost Modeling Framework for Renewable Energy Studies: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Gallo, Giulia

    2015-10-07

    The agent-based framework for renewable energy studies (ARES) is an integrated approach that adds an agent-based model of industry actors to PLEXOS and combines the strengths of the two to overcome their individual shortcomings. It can examine existing and novel wholesale electricity markets under high penetrations of renewables. ARES is demonstrated by studying how increasing levels of wind will impact the operations and the exercise of market power of generation companies that exploit an economic withholding strategy. The analysis is carried out on a test system that represents the Electric Reliability Council of Texas energy-only market in the year 2020. The results more realistically reproduce the operations of an energy market under different and increasing penetrations of wind, and ARES can be extended to address pressing issues in current and future wholesale electricity markets.

  10. Artificial Immune Systems Metaphor for Agent Based Modeling of Crisis Response Operations

    CERN Document Server

    Khalil, Khaled M; Nazmy, Taymour T; Salem, Abdel-Badeeh M

    2010-01-01

    Crisis response requires information intensive efforts utilized for reducing uncertainty, calculating and comparing costs and benefits, and managing resources in a fashion beyond those regularly available to handle routine problems. This paper presents an Artificial Immune Systems (AIS) metaphor for agent based modeling of crisis response operations. The presented model proposes integration of hybrid set of aspects (multi-agent systems, built-in defensive model of AIS, situation management, and intensity-based learning) for crisis response operations. In addition, the proposed response model is applied on the spread of pandemic influenza in Egypt as a case study.

  11. A Harris-Todaro Agent-Based Model to Rural-Urban Migration

    CERN Document Server

    Espindola, A L; Silveira, J J; Espindola, Aquino L.; Silveira, Jaylson J.

    2005-01-01

    The Harris-Todaro model of the rural-urban migration process is revisited under an agent-based approach. The migration of the workers is interpreted as a process of social learning by imitation, formalized by a computational model. By simulating this model, we observe a transitional dynamics with continuous growth of the urban fraction of overall population toward an equilibrium. Such an equilibrium is characterized by stabilization of rural-urban expected wages differential (generalized Harris-Todaro equilibrium condition), urban concentration and urban unemployment. These classic results obtained originally by Harris and Todaro are emergent properties of our model.

  12. Fabrication and evaluation of tumor-targeted positive MRI contrast agent based on ultrasmall MnO nanoparticles.

    Science.gov (United States)

    Huang, Haitao; Yue, Tao; Xu, Ke; Golzarian, Jafar; Yu, Jiahui; Huang, Jin

    2015-07-01

    Gd(III) chelate is currently used as positive magnetic resonance imaging (MRI) contrast agent in clinical diagnosis, but generally induces the risk of nephrogenic systemic fibrosis (NSF) due to the dissociated Gd(3+) from Gd(III) chelates. To develop a novel positive MRI contrast agent with low toxicity and high sensitivity, ultrasmall MnO nanoparticles were PEGylated via catechol-Mn chelation and conjugated with cRGD as active targeting function to tumor. Particularly, the MnO nanoparticles with a size of ca. 5nm were modified by α,β-poly(aspartic acid)-based graft polymer containing PEG and DOPA moieties and, meanwhile, conjugated with cRGD to produce the contrast agent with a size of ca. 100nm and a longitudinal relaxivity (r1) of 10.2mM(-1)S(-1). Such nanoscaled contrast agent integrated passive- and active-targeting function to tumor, and its efficient accumulation behavior in tumor was verified by in vivo distribution study. At the same time, the PEG moiety played a role of hydrophilic coating to improve the biocompatibility and stability under storing and physiological conditions, and especially might guarantee enough circulation time in blood. Moreover, in vivo MRI revealed a good and long-term effect of enhancing MRI signal for as-fabricated contrast agent while cell viability assay proved its acceptable cytotoxicity for MRI application. On the whole, the as-fabricated PEGylated and cRGD-functionalized contrast agent based on ultrasmall MnO nanoparticles showed a great potential to the T1-weighted MRI diagnosis of tumor.

  13. Agent-based Ecological Model Calibration - on the Edge of a New Approach

    CERN Document Server

    Pereira, Antonio; Reis, Luis Paulo

    2008-01-01

    The purpose of this paper is to present a new approach to ecological model calibration -- an agent-based software. This agent works on three stages: 1- It builds a matrix that synthesizes the inter-variable relationships; 2- It analyses the steady-state sensitivity of different variables to different parameters; 3- It runs the model iteratively and measures model lack of fit, adequacy and reliability. Stage 3 continues until some convergence criteria are attained. At each iteration, the agent knows from stages 1 and 2, which parameters are most likely to produce the desired shift on predicted results.

  14. An agent-based computational model of the spread of tuberculosis

    International Nuclear Information System (INIS)

    In this work we propose an alternative model of the spread of tuberculosis (TB) and the emergence of drug resistance due to the treatment with antibiotics. We implement the simulations by an agent-based model computational approach where the spatial structure is taken into account. The spread of tuberculosis occurs according to probabilities defined by the interactions among individuals. The model was validated by reproducing results already known from the literature in which different treatment regimes yield the emergence of drug resistance. The different patterns of TB spread can be visualized at any time of the system evolution. The implementation details as well as some results of this alternative approach are discussed

  15. Combining Bayesian Networks and Agent Based Modeling to develop a decision-support model in Vietnam

    Science.gov (United States)

    Nong, Bao Anh; Ertsen, Maurits; Schoups, Gerrit

    2016-04-01

    Complexity and uncertainty in natural resources management have been focus themes in recent years. Within these debates, with the aim to define an approach feasible for water management practice, we are developing an integrated conceptual modeling framework for simulating decision-making processes of citizens, in our case in the Day river area, Vietnam. The model combines Bayesian Networks (BNs) and Agent-Based Modeling (ABM). BNs are able to combine both qualitative data from consultants / experts / stakeholders, and quantitative data from observations on different phenomena or outcomes from other models. Further strengths of BNs are that the relationship between variables in the system is presented in a graphical interface, and that components of uncertainty are explicitly related to their probabilistic dependencies. A disadvantage is that BNs cannot easily identify the feedback of agents in the system once changes appear. Hence, ABM was adopted to represent the reaction among stakeholders under changes. The modeling framework is developed as an attempt to gain better understanding about citizen's behavior and factors influencing their decisions in order to reduce uncertainty in the implementation of water management policy.

  16. Agent-based financial dynamics model from stochastic interacting epidemic system and complexity analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Yunfan, E-mail: yunfanlu@yeah.net; Wang, Jun; Niu, Hongli

    2015-06-12

    An agent-based financial stock price model is developed and investigated by a stochastic interacting epidemic system, which is one of the statistical physics systems and has been used to model the spread of an epidemic or a forest fire. Numerical and statistical analysis are performed on the simulated returns of the proposed financial model. Complexity properties of the financial time series are explored by calculating the correlation dimension and using the modified multiscale entropy method. In order to verify the rationality of the financial model, the real stock market indexes, Shanghai Composite Index and Shenzhen Component Index, are studied in comparison with the simulation data of the proposed model for the different infectiousness parameters. The empirical research reveals that this financial model can reproduce some important features of the real stock markets. - Highlights: • A new agent-based financial price model is developed by stochastic interacting epidemic system. • The structure of the proposed model allows to simulate the financial dynamics. • Correlation dimension and MMSE are applied to complexity analysis of financial time series. • Empirical results show the rationality of the proposed financial model.

  17. Walk This Way: Improving Pedestrian Agent-Based Models through Scene Activity Analysis

    Directory of Open Access Journals (Sweden)

    Andrew Crooks

    2015-09-01

    Full Text Available Pedestrian movement is woven into the fabric of urban regions. With more people living in cities than ever before, there is an increased need to understand and model how pedestrians utilize and move through space for a variety of applications, ranging from urban planning and architecture to security. Pedestrian modeling has been traditionally faced with the challenge of collecting data to calibrate and validate such models of pedestrian movement. With the increased availability of mobility datasets from video surveillance and enhanced geolocation capabilities in consumer mobile devices we are now presented with the opportunity to change the way we build pedestrian models. Within this paper we explore the potential that such information offers for the improvement of agent-based pedestrian models. We introduce a Scene- and Activity-Aware Agent-Based Model (SA2-ABM, a method for harvesting scene activity information in the form of spatiotemporal trajectories, and incorporate this information into our models. In order to assess and evaluate the improvement offered by such information, we carry out a range of experiments using real-world datasets. We demonstrate that the use of real scene information allows us to better inform our model and enhance its predictive capabilities.

  18. Genetic Algorithms for Agent-Based Infrastructure Interdependency Modeling and Analysis

    Energy Technology Data Exchange (ETDEWEB)

    May Permann

    2007-03-01

    Today’s society relies greatly upon an array of complex national and international infrastructure networks such as transportation, electric power, telecommunication, and financial networks. This paper describes initial research combining agent-based infrastructure modeling software and genetic algorithms (GAs) to help optimize infrastructure protection and restoration decisions. This research proposes to apply GAs to the problem of infrastructure modeling and analysis in order to determine the optimum assets to restore or protect from attack or other disaster. This research is just commencing and therefore the focus of this paper is the integration of a GA optimization method with a simulation through the simulation’s agents.

  19. Dosage and dose schedule screening of drug combinations in agent-based models reveals hidden synergies

    Directory of Open Access Journals (Sweden)

    Lisa Corina Barros de Andrade e Sousa1

    2016-01-01

    Full Text Available The fungus Candida albicans is the most common causative agent of human fungal infections and better drugs or drug combination strategies are urgently needed. Here, we present an agent-based model of the interplay of C. albicans with the host immune system and with the microflora of the host. We took into account the morphological change of C. albicans from the yeast to hyphae form and its dynamics during infection. The model allowed us to follow the dynamics of fungal growth and morphology, of the immune cells and of microflora in different perturbing situations. We specifically focused on the consequences of microflora reduction following antibiotic treatment. Using the agent-based model, different drug types have been tested for their effectiveness, namely drugs that inhibit cell division and drugs that constrain the yeast-to-hyphae transition. Applied individually, the division drug turned out to successfully decrease hyphae while the transition drug leads to a burst in hyphae after the end of the treatment. To evaluate the effect of different drug combinations, doses, and schedules, we introduced a measure for the return to a healthy state, the infection score. Using this measure, we found that the addition of a transition drug to a division drug treatment can improve the treatment reliability while minimizing treatment duration and drug dosage. In this work we present a theoretical study. Although our model has not been calibrated to quantitative experimental data, the technique of computationally identifying synergistic treatment combinations in an agent based model exemplifies the importance of computational techniques in translational research.

  20. Mapping Cyclists’ Experiences and Agent-Based Modelling of Their Wayfinding Behaviour

    DEFF Research Database (Denmark)

    Snizek, Bernhard

    This dissertation is about modelling cycling transport behaviour. It is partly about urban experiences seen by the cyclist and about modelling, more specifically the agent-based modelling of cyclists' wayfinding behaviour. The dissertation consists of three papers. The first deals with the develo......This dissertation is about modelling cycling transport behaviour. It is partly about urban experiences seen by the cyclist and about modelling, more specifically the agent-based modelling of cyclists' wayfinding behaviour. The dissertation consists of three papers. The first deals......-based model of cycling transport behaviour using geodata, data from the Danish travel survey as well as behavioural data extracted from trajectories recorded utilising GPS units. Mapping Bicyclists’ Experiences in Copenhagen This paper presents an approach to the collection, mapping and analysing of cyclists......’ experiences. By relating spatial experiences to urban indicators such as land-use, street characteristics, cycle infrastructure, centrality and other aspects of the urban environment, their influence on cyclists’ experiences were analysed. 398 cyclists responded and plotted their most recent cycle route...

  1. Agent-Based and Macroscopic Modeling of the Complex Socio-Economic Systems

    Directory of Open Access Journals (Sweden)

    Aleksejus Kononovičius

    2013-08-01

    Full Text Available Purpose – The focus of this contribution is the correspondence between collective behavior and inter-individual interactions in the complex socio-economic systems. Currently there is a wide selection of papers proposing various models for the both collective behavior and inter-individual interactions in the complex socio-economic systems. Yet the papers directly relating these two concepts are still quite rare. By studying this correspondence we discuss a cutting edge approach to the modeling of complex socio-economic systems. Design/methodology/approach – The collective behavior is often modeled using stochastic and ordinary calculus, while the inter-individual interactions are modeled using agent-based models. In order to obtain the ideal model, one should start from these frameworks and build a bridge to reach another. This is a formidable task, if we consider the top-down approach, namely starting from the collective behavior and moving towards inter-individual interactions. The bottom-up approach also fails, if complex inter-individual interaction models are considered, yet in this case we can start with simple models and increase the complexity as needed. Findings – The bottom-up approach, considering simple agent-based herding model as a model for the inter-individual interactions, allows us to derive certain macroscopic models of the complex socio-economic systems from the agent-based perspective. This provides interesting insights into the collective behavior patterns observed in the complex socio-economic systems. Research limitations/implications –The simplicity of the agent-based herding model might be considered to be somewhat limiting. Yet this simplicity implies that the model is highly universal. It reproduces universal features of social behavior and also can be further extended to fit different socio-economic scenarios. Practical implications – Insights provided in this contribution might be used to modify existing

  2. An Agent-Based Model of Farmer Decision Making in Jordan

    Science.gov (United States)

    Selby, Philip; Medellin-Azuara, Josue; Harou, Julien; Klassert, Christian; Yoon, Jim

    2016-04-01

    We describe an agent based hydro-economic model of groundwater irrigated agriculture in the Jordan Highlands. The model employs a Multi-Agent-Simulation (MAS) framework and is designed to evaluate direct and indirect outcomes of climate change scenarios and policy interventions on farmer decision making, including annual land use, groundwater use for irrigation, and water sales to a water tanker market. Land use and water use decisions are simulated for groups of farms grouped by location and their behavioural and economic similarities. Decreasing groundwater levels, and the associated increase in pumping costs, are important drivers for change within Jordan'S agricultural sector. We describe how this is considered by coupling of agricultural and groundwater models. The agricultural production model employs Positive Mathematical Programming (PMP), a method for calibrating agricultural production functions to observed planted areas. PMP has successfully been used with disaggregate models for policy analysis. We adapt the PMP approach to allow explicit evaluation of the impact of pumping costs, groundwater purchase fees and a water tanker market. The work demonstrates the applicability of agent-based agricultural decision making assessment in the Jordan Highlands and its integration with agricultural model calibration methods. The proposed approach is designed and implemented with software such that it could be used to evaluate a variety of physical and human influences on decision making in agricultural water management.

  3. Income Tax Evasion Dynamics: Evidence from an Agent-based Econophysics Model

    CERN Document Server

    Pickhardt, Michael

    2011-01-01

    We analyze income tax evasion dynamics in a standard model of statistical mechanics, the Ising model of ferromagnetism. However, in contrast to previous research, we use an inhomogeneous multi-dimensional Ising model where the local degrees of freedom (agents) are subject to a specific social temperature and coupled to external fields which govern their social behavior. This new modeling frame allows for analyzing large societies of four different and interacting agent types. As a second novelty, our model may reproduce results from agent-based models that incorporate standard Allingham and Sandmo tax evasion features as well as results from existing two-dimensional Ising based tax evasion models. We then use our model for analyzing income tax evasion dynamics under different enforcement scenarios and point to some policy implications.

  4. Agent-based model of angiogenesis simulates capillary sprout initiation in multicellular networks.

    Science.gov (United States)

    Walpole, J; Chappell, J C; Cluceru, J G; Mac Gabhann, F; Bautch, V L; Peirce, S M

    2015-09-01

    Many biological processes are controlled by both deterministic and stochastic influences. However, efforts to model these systems often rely on either purely stochastic or purely rule-based methods. To better understand the balance between stochasticity and determinism in biological processes a computational approach that incorporates both influences may afford additional insight into underlying biological mechanisms that give rise to emergent system properties. We apply a combined approach to the simulation and study of angiogenesis, the growth of new blood vessels from existing networks. This complex multicellular process begins with selection of an initiating endothelial cell, or tip cell, which sprouts from the parent vessels in response to stimulation by exogenous cues. We have constructed an agent-based model of sprouting angiogenesis to evaluate endothelial cell sprout initiation frequency and location, and we have experimentally validated it using high-resolution time-lapse confocal microscopy. ABM simulations were then compared to a Monte Carlo model, revealing that purely stochastic simulations could not generate sprout locations as accurately as the rule-informed agent-based model. These findings support the use of rule-based approaches for modeling the complex mechanisms underlying sprouting angiogenesis over purely stochastic methods. PMID:26158406

  5. Effect of individual protective behaviors on influenza transmission: an agent-based model.

    Science.gov (United States)

    Karimi, Elnaz; Schmitt, Ketra; Akgunduz, Ali

    2015-09-01

    It is well established in the epidemiological literature that individual behaviors have a significant effect on the spread of infectious diseases. Agent-based models are increasingly being recognized as the next generation of epidemiological models. In this research, we use the ability of agent-based models to incorporate behavior into simulations by examining the relative importance of vaccination and social distancing, two common measures for controlling the spread of infectious diseases, with respect to seasonal influenza. We modeled health behaviour using the result of a Health Belief Model study focused on influenza. We considered a control and a treatment group to explore the effect of education on people's health-related behaviors patterns. The control group reflects the behavioral patterns of students based on their general knowledge of influenza and its interventions while the treatment group illustrates the level of behavioral changes after individuals have been educated by a health care expert. The results of this study indicate that self-initiated behaviors are successful in controlling an outbreak in a high contact rate location such as a university. Self-initiated behaviors resulted in a population attack rate decrease of 17% and a 25% reduction in the peak number of cases. The simulation also provides significant evidence for the effect of an HBM theory-based educational program to increase the rate of applying the target interventions (vaccination by 22% percent and social distancing by 41%) and consequently to control the outbreak. PMID:25578039

  6. A Call to Arms: Standards for Agent-Based Modeling and Simulation

    OpenAIRE

    Andrew Collins; Mikel Petty; Daniele Vernon-Bido; Solomon Sherfey

    2015-01-01

    Standards are as old as civilization itself and they are vital to human development. Standards touch almost every part of our lives, from the water we drink to the language used to write this article. A sign of a good standard is one that we do not notice. Good standards exist and so do processes and organizations to create and maintain them. As agent-based modeling and simulation matures as a methodology, a discussion of standards applicable to it becomes increasingly important. Descriptive ...

  7. The "Wedding-Ring": An agent-based marriage model based on social interaction

    Directory of Open Access Journals (Sweden)

    Alexia Prskawetz

    2007-08-01

    Full Text Available In this paper we develop an agent-based marriage model based on social interaction. We build an population of interacting agents whose chances of marrying depend on the availability of partners, and whose willingness to marry depends on the share of relevant others in their social network who are already married. We then let the typical aggregate age pattern of marriage emerge from the bottom-up. The results of our simulation show that micro-level hypotheses founded on existing theory and evidence on social interaction can reproduce age-at-marriage patterns with both realistic shape and realistic micro-level dynamics.

  8. Using an Agent-Based Modeling Simulation and Game to Teach Socio-Scientific Topics

    Directory of Open Access Journals (Sweden)

    Lori L. Scarlatos

    2014-02-01

    Full Text Available In our modern world, where science, technology and society are tightly interwoven, it is essential that all students be able to evaluate scientific evidence and make informed decisions. Energy Choices, an agent-based simulation with a multiplayer game interface, was developed as a learning tool that models the interdependencies between the energy choices that are made, growth in local economies, and climate change on a global scale. This paper presents the results of pilot testing Energy Choices in two different settings, using two different modes of delivery.

  9. An Agent-Based Dynamic Model for Analysis of Distributed Space Exploration Architectures

    Science.gov (United States)

    Sindiy, Oleg V.; DeLaurentis, Daniel A.; Stein, William B.

    2009-07-01

    A range of complex challenges, but also potentially unique rewards, underlie the development of exploration architectures that use a distributed, dynamic network of resources across the solar system. From a methodological perspective, the prime challenge is to systematically model the evolution (and quantify comparative performance) of such architectures, under uncertainty, to effectively direct further study of specialized trajectories, spacecraft technologies, concept of operations, and resource allocation. A process model for System-of-Systems Engineering is used to define time-varying performance measures for comparative architecture analysis and identification of distinguishing patterns among interoperating systems. Agent-based modeling serves as the means to create a discrete-time simulation that generates dynamics for the study of architecture evolution. A Solar System Mobility Network proof-of-concept problem is introduced representing a set of longer-term, distributed exploration architectures. Options within this set revolve around deployment of human and robotic exploration and infrastructure assets, their organization, interoperability, and evolution, i.e., a system-of-systems. Agent-based simulations quantify relative payoffs for a fully distributed architecture (which can be significant over the long term), the latency period before they are manifest, and the up-front investment (which can be substantial compared to alternatives). Verification and sensitivity results provide further insight on development paths and indicate that the framework and simulation modeling approach may be useful in architectural design of other space exploration mass, energy, and information exchange settings.

  10. Introducing spatial information into predictive NF-kappaB modelling--an agent-based approach.

    Directory of Open Access Journals (Sweden)

    Mark Pogson

    Full Text Available Nature is governed by local interactions among lower-level sub-units, whether at the cell, organ, organism, or colony level. Adaptive system behaviour emerges via these interactions, which integrate the activity of the sub-units. To understand the system level it is necessary to understand the underlying local interactions. Successful models of local interactions at different levels of biological organisation, including epithelial tissue and ant colonies, have demonstrated the benefits of such 'agent-based' modelling. Here we present an agent-based approach to modelling a crucial biological system--the intracellular NF-kappaB signalling pathway. The pathway is vital to immune response regulation, and is fundamental to basic survival in a range of species. Alterations in pathway regulation underlie a variety of diseases, including atherosclerosis and arthritis. Our modelling of individual molecules, receptors and genes provides a more comprehensive outline of regulatory network mechanisms than previously possible with equation-based approaches. The method also permits consideration of structural parameters in pathway regulation; here we predict that inhibition of NF-kappaB is directly affected by actin filaments of the cytoskeleton sequestering excess inhibitors, therefore regulating steady-state and feedback behaviour.

  11. Agent-based modeling of the energy network for hybrid cars

    International Nuclear Information System (INIS)

    Highlights: • An approach to represent and calculate multicarrier energy networks has been developed. • It provides a modeling method based on agents, for multicarrier energy networks. • It allows the system representation on a single sheet. • Energy flows circulating in the system can be observed dynamically during simulation. • The method is technology independent. - Abstract: Studies in complex energy networks devoted to the modeling of electrical power grids, were extended in previous work, where a computational multi-layered ontology, implemented using agent-based methods, was adopted. This structure is compatible with recently introduced Multiplex Networks which using Multi-linear Algebra generalize some of classical results for single-layer networks, to multilayer networks in steady state. Static results do not assist overly in understanding dynamic networks in which the values of the variables in the nodes and edges can change suddenly, driven by events, and even where new nodes or edges may appear or disappear, also because of other events. To address this gap, a computational agent-based model is developed to extend the multi-layer and multiplex approaches. In order to demonstrate the benefits of a dynamical extension, a model of the energy network in a hybrid car is presented as a case study

  12. Turning green: Agent-based modeling of the adoption of dynamic electricity tariffs

    International Nuclear Information System (INIS)

    Using an agent-based modeling approach we study the temporal dynamics of consumer opinions regarding switching to dynamic electricity tariffs and the actual decisions to switch. We assume that the decision to switch is based on the unanimity of τ past opinions. The resulting model offers a hypothetical, yet plausible explanation of why there is such a big discrepancy between consumer opinions, as measured by market surveys, and the actual participation in pilot programs and the adoption of dynamic tariffs. We argue that due to the high indifference level in today's retail electricity markets, customer opinions are very unstable and change frequently. The conducted simulation study shows that reducing the indifference level can result in narrowing the intention–behavior gap. A similar effect can be achieved by decreasing the decision time that a consumer takes to make a decision. - Highlights: • We propose an agent-based model to study the adoption of dynamic electricity tariffs. • The decision to change the tariff is based on the unanimity of τ past opinions. • The model explains why the empirically observed intention–behavior gap exists. • The adoption of dynamic tariffs is impossible due to the high level of indifference in today's societies. • Reducing the indifference level or decreasing the decision time can result in narrowing the gap

  13. Agent Based Fuzzy T-S Multi-Model System and Its Applications

    Directory of Open Access Journals (Sweden)

    Xiaopeng Zhao

    2015-11-01

    Full Text Available Based on the basic concepts of agent and fuzzy T-S model, an agent based fuzzy T-S multi-model (ABFT-SMM system is proposed in this paper. Different from the traditional method, the parameters and the membership value of the agent can be adjusted along with the process. In this system, each agent can be described as a dynamic equation, which can be seen as the local part of the multi-model, and it can execute the task alone or collaborate with other agents to accomplish a fixed goal. It is proved in this paper that the agent based fuzzy T-S multi-model system can approximate any linear or nonlinear system at arbitrary accuracy. The applications to the benchmark problem of chaotic time series prediction, water heater system and waste heat utilizing process illustrate the viability and the efficiency of the mentioned approach. At the same time, the method can be easily used to a number of engineering fields, including identification, nonlinear control, fault diagnostics and performance analysis.

  14. Combining agent-based modeling and life cycle assessment for the evaluation of mobility policies.

    Science.gov (United States)

    Florent, Querini; Enrico, Benetto

    2015-02-01

    This article presents agent-based modeling (ABM) as a novel approach for consequential life cycle assessment (C-LCA) of large scale policies, more specifically mobility-related policies. The approach is validated at the Luxembourgish level (as a first case study). The agent-based model simulates the car market (sales, use, and dismantling) of the population of users in the period 2013-2020, following the implementation of different mobility policies and available electric vehicles. The resulting changes in the car fleet composition as well as the hourly uses of the vehicles are then used to derive consistent LCA results, representing the consequences of the policies. Policies will have significant environmental consequences: when using ReCiPe2008, we observe a decrease of global warming, fossil depletion, acidification, ozone depletion, and photochemical ozone formation and an increase of metal depletion, ionizing radiations, marine eutrophication, and particulate matter formation. The study clearly shows that the extrapolation of LCA results for the circulating fleet at national scale following the introduction of the policies from the LCAs of single vehicles by simple up-scaling (using hypothetical deployment scenarios) would be flawed. The inventory has to be directly conducted at full scale and to this aim, ABM is indeed a promising approach, as it allows identifying and quantifying emerging effects while modeling the Life Cycle Inventory of vehicles at microscale through the concept of agents. PMID:25587896

  15. An Agent Based Intrusion Detection Model for Mobile Ad Hoc Networks

    Directory of Open Access Journals (Sweden)

    B. M. Reshmi

    2006-01-01

    Full Text Available Intrusion detection has over the last few years, assumed paramount importance within the broad realm of network security, more so in case of wireless mobile ad hoc networks. The inherently vulnerable characteristics of wireless mobile ad hoc networks make them susceptible to attacks in-spite of some security measures, and it may be too late before any counter action can take effect. As such, there is a need to complement traditional security mechanisms with efficient intrusion detection and response systems. This paper proposes an agent-based model to address the aspect of intrusion detection in cluster based mobile wireless ad hoc network environment. The model comprises of a set of static and mobile agents, which are used to detect intrusions, respond to intrusions, and distribute selected and aggregated intrusion information to all other nodes in the network in an intelligent manner. The model is simulated to test its operation effectiveness by considering the performance parameters such as, detection rate, false positives, agent overheads, and intrusion information distribution time. Agent based approach facilitates flexible and adaptable security services. Also, it supports component based software engineering components such as maintainability, reachability, reusability, adaptability, flexibility, and customization.

  16. cystiSim - an agent-based model for Taenia solium transmission and control

    DEFF Research Database (Denmark)

    Braae, Uffe Christian; Devleesschauwer, Brecht; Gabriël, Sarah;

    Taenia solium taeniosis/cysticercosis was declared eradicable by the International Task Force for Disease Eradication in 1993, but remains a neglected zoonosis due to limited information about its transmission and validation of intervention tools. To address this gap, we developed cysti......Sim, an agent-based model for T. solium transmission and control. The model was developed in R and is publicly available as an R package (https://github.com/brechtdv/cystiSim/). The model description adheres to the Overview, Design concepts, and Details (ODD) protocol. The model consists of two entities: pigs...... in reduction of T. solium prevalence. Human MDA is the least effective intervention measure. In comparison with an existing mathematical model for T. solium transmission, cystiSim also includes parasite maturation, host immunity, and environmental contamination. Adding these key biological parameters...

  17. A Computational Agent-Based Modeling Approach for Competitive Wireless Service Market

    KAUST Repository

    Douglas, C C

    2011-04-01

    Using an agent-based modeling method, we study market dynamism with regard to wireless cellular services that are in competition for a greater market share and profit. In the proposed model, service providers and consumers are described as agents who interact with each other and actively participate in an economically well-defined marketplace. Parameters of the model are optimized using the Levenberg-Marquardt method. The quantitative prediction capabilities of the proposed model are examined through data reproducibility using past data from the U.S. and Korean wireless service markets. Finally, we investigate a disruptive market event, namely the introduction of the iPhone into the U.S. in 2007 and the resulting changes in the modeling parameters. We predict and analyze the impacts of the introduction of the iPhone into the Korean wireless service market assuming a release date of 2Q09 based on earlier data. © 2011 IEEE.

  18. Encouraging Sustainable Transport Choices in American Households: Results from an Empirically Grounded Agent-Based Model

    Directory of Open Access Journals (Sweden)

    Davide Natalini

    2013-12-01

    Full Text Available The transport sector needs to go through an extended process of decarbonisation to counter the threat of climate change. Unfortunately, the International Energy Agency forecasts an enormous growth in the number of cars and greenhouse gas emissions by 2050. Two issues can thus be identified: (1 the need for a new methodology that could evaluate the policy performances ex-ante and (2 the need for more effective policies. To help address these issues, we developed an Agent-Based Model called Mobility USA aimed at: (1 testing whether this could be an effective approach in analysing ex-ante policy implementation in the transport sector; and (2 evaluating the effects of alternative policy scenarios on commuting behaviours in the USA. Particularly, we tested the effects of two sets of policies, namely market-based and preference-change ones. The model results suggest that this type of agent-based approach will provide a useful tool for testing policy interventions and their effectiveness.

  19. Multiple Servers - Queue Model for Agent Based Technology in Cache Consistence Maintenance of Mobile Environment

    Directory of Open Access Journals (Sweden)

    G.Shanmugarathinam

    2013-01-01

    Full Text Available Caching is one of the important techniques in mobile computing. In caching, frequently accessed data is stored in mobile clients to avoid network traffic and improve the performance in mobile computing. In a mobile computing environment, the number of mobile users increases and requests the server for any updation, but most of the time the server is busy and the client has to wait for a long time. The cache consistency maintenance is difficult for both client and the server. This paper is proposes a technique using a queuing system consisting of one or more servers that provide services of some sort to arrive mobile hosts using agent based technology. This services mechanism of a queuing system is specified by the number of servers each server having its own queue, Agent based technology will maintain the cache consistency between the client and the server .This model saves wireless bandwidth, reduces network traffic and reduces the workload on the server. The simulation result was analyzed with previous technique and the proposed model shows significantly better performance than the earlier approach.

  20. A Transport Model of Mobile Agent Based on Secure Hybrid Encryption

    Institute of Scientific and Technical Information of China (English)

    SUNZhixin; CHENZhixian; WANGRuchuan

    2005-01-01

    The solution of security problems of mobile agents is a key issue, which will decide whether mobile agents can be widely used. The paper analyzes main security problems, which currently are confronted with mobile agent systems and existing protection solutions. And then the paper presents a Security Transport model of mobile agents based on a hybrid encryption algorithm (TMSHE).Meanwhile, it expatiates on implementation of the algorithm. The algorithm of TMSHE model mainly consists of two parts, i.e., employing a hybrid encryption algorithm to encrypt mobile agents and using Transport layer security (TLS) to encrypt communication channel. Mobile agents by hybrid encryption move through communication channels, which are encrypted by TLS. The simulation results indicate that the model can protect mobile agents' security effectively, and consequently the security and steadiness of the whole mobile agent system are also improved. The model has succeeded in getting application in a prototypesystem- Intrusion detection system based on mobile agents.

  1. Agent-based modeling: a new approach for theory building in social psychology.

    Science.gov (United States)

    Smith, Eliot R; Conrey, Frederica R

    2007-02-01

    Most social and psychological phenomena occur not as the result of isolated decisions by individuals but rather as the result of repeated interactions between multiple individuals over time. Yet the theory-building and modeling techniques most commonly used in social psychology are less than ideal for understanding such dynamic and interactive processes. This article describes an alternative approach to theory building, agent-based modeling (ABM), which involves simulation of large numbers of autonomous agents that interact with each other and with a simulated environment and the observation of emergent patterns from their interactions. The authors believe that the ABM approach is better able than prevailing approaches in the field, variable-based modeling (VBM) techniques such as causal modeling, to capture types of complex, dynamic, interactive processes so important in the social world. The article elaborates several important contrasts between ABM and VBM and offers specific recommendations for learning more and applying the ABM approach. PMID:18453457

  2. An agent-based simulation model to study accountable care organizations.

    Science.gov (United States)

    Liu, Pai; Wu, Shinyi

    2016-03-01

    Creating accountable care organizations (ACOs) has been widely discussed as a strategy to control rapidly rising healthcare costs and improve quality of care; however, building an effective ACO is a complex process involving multiple stakeholders (payers, providers, patients) with their own interests. Also, implementation of an ACO is costly in terms of time and money. Immature design could cause safety hazards. Therefore, there is a need for analytical model-based decision-support tools that can predict the outcomes of different strategies to facilitate ACO design and implementation. In this study, an agent-based simulation model was developed to study ACOs that considers payers, healthcare providers, and patients as agents under the shared saving payment model of care for congestive heart failure (CHF), one of the most expensive causes of sometimes preventable hospitalizations. The agent-based simulation model has identified the critical determinants for the payment model design that can motivate provider behavior changes to achieve maximum financial and quality outcomes of an ACO. The results show nonlinear provider behavior change patterns corresponding to changes in payment model designs. The outcomes vary by providers with different quality or financial priorities, and are most sensitive to the cost-effectiveness of CHF interventions that an ACO implements. This study demonstrates an increasingly important method to construct a healthcare system analytics model that can help inform health policy and healthcare management decisions. The study also points out that the likely success of an ACO is interdependent with payment model design, provider characteristics, and cost and effectiveness of healthcare interventions. PMID:24715674

  3. The Evolution of Cooperation in Managed Groundwater Systems: An Agent-Based Modelling Approach

    Science.gov (United States)

    Castilla Rho, J. C.; Mariethoz, G.; Rojas, R. F.; Andersen, M. S.; Kelly, B. F.; Holley, C.

    2014-12-01

    Human interactions with groundwater systems often exhibit complex features that hinder the sustainable management of the resource. This leads to costly and persistent conflicts over groundwater at the catchment scale. One possible way to address these conflicts is by gaining a better understanding of how social and groundwater dynamics coevolve using agent-based models (ABM). Such models allow exploring 'bottom-up' solutions (i.e., self-organised governance systems), where the behaviour of individual agents (e.g., farmers) results in the emergence of mutual cooperation among groundwater users. There is significant empirical evidence indicating that this kind of 'bottom-up' approach may lead to more enduring and sustainable outcomes, compared to conventional 'top-down' strategies such as centralized control and water right schemes (Ostrom 1990). New modelling tools are needed to study these concepts systematically and efficiently. Our model uses a conceptual framework to study cooperation and the emergence of social norms as initially proposed by Axelrod (1986), which we adapted to groundwater management. We developed an ABM that integrates social mechanisms and the physics of subsurface flow. The model explicitly represents feedback between groundwater conditions and social dynamics, capturing the spatial structure of these interactions and the potential effects on cooperation levels in an agricultural setting. Using this model, we investigate a series of mechanisms that may trigger norms supporting cooperative strategies, which can be sustained and become stable over time. For example, farmers in a self-monitoring community can be more efficient at achieving the objective of sustainable groundwater use than government-imposed regulation. Our coupled model thus offers a platform for testing new schemes promoting cooperation and improved resource use, which can be used as a basis for policy design. Importantly, we hope to raise awareness of agent-based modelling as

  4. Agent-based model with asymmetric trading and herding for complex financial systems.

    Directory of Open Access Journals (Sweden)

    Jun-Jie Chen

    Full Text Available BACKGROUND: For complex financial systems, the negative and positive return-volatility correlations, i.e., the so-called leverage and anti-leverage effects, are particularly important for the understanding of the price dynamics. However, the microscopic origination of the leverage and anti-leverage effects is still not understood, and how to produce these effects in agent-based modeling remains open. On the other hand, in constructing microscopic models, it is a promising conception to determine model parameters from empirical data rather than from statistical fitting of the results. METHODS: To study the microscopic origination of the return-volatility correlation in financial systems, we take into account the individual and collective behaviors of investors in real markets, and construct an agent-based model. The agents are linked with each other and trade in groups, and particularly, two novel microscopic mechanisms, i.e., investors' asymmetric trading and herding in bull and bear markets, are introduced. Further, we propose effective methods to determine the key parameters in our model from historical market data. RESULTS: With the model parameters determined for six representative stock-market indices in the world, respectively, we obtain the corresponding leverage or anti-leverage effect from the simulation, and the effect is in agreement with the empirical one on amplitude and duration. At the same time, our model produces other features of the real markets, such as the fat-tail distribution of returns and the long-term correlation of volatilities. CONCLUSIONS: We reveal that for the leverage and anti-leverage effects, both the investors' asymmetric trading and herding are essential generation mechanisms. Among the six markets, however, the investors' trading is approximately symmetric for the five markets which exhibit the leverage effect, thus contributing very little. These two microscopic mechanisms and the methods for the

  5. Evaluating network analysis and agent based modeling for investigating the stability of commercial air carrier schedules

    Science.gov (United States)

    Conway, Sheila Ruth

    For a number of years, the United States Federal Government has been formulating the Next Generation Air Transportation System plans for National Airspace System improvement. These improvements attempt to address air transportation holistically, but often address individual improvements in one arena such as ground or in-flight equipment. In fact, air transportation system designers have had only limited success using traditional Operations Research and parametric modeling approaches in their analyses of innovative operations. They need a systemic methodology for modeling of safety-critical infrastructure that is comprehensive, objective, and sufficiently concrete, yet simple enough to be deployed with reasonable investment. The methodology must also be amenable to quantitative analysis so issues of system safety and stability can be rigorously addressed. The literature suggests that both agent-based models and network analysis techniques may be useful for complex system development and analysis. The purpose of this research is to evaluate these two techniques as applied to analysis of commercial air carrier schedule (route) stability in daily operations, an important component of air transportation. Airline-like routing strategies are used to educe essential elements of applying the method. Two main models are developed, one investigating the network properties of the route structure, the other an Agent-based approach. The two methods are used to predict system properties at a macro-level. These findings are compared to observed route network performance measured by adherence to a schedule to provide validation of the results. Those interested in complex system modeling are provided some indication as to when either or both of the techniques would be applicable. For aviation policy makers, the results point to a toolset capable of providing insight into the system behavior during the formative phases of development and transformation with relatively low investment

  6. Agent based spin model for financial markets on regular lattices and complex networks

    Science.gov (United States)

    Kim, Hong-Joo; Yook, Soon-Hyung; Kim, Yup

    2008-03-01

    We study an agent based microscopic model for price formation in financial markets on various topologies motivated by the dynamics of agents. The model consists of interacting agents (spins) with localand global couplings. The local interaction denotes the tendency of agents to make the same decision with their interacting partners. On the other hand, the global coupling to the self-generating field represents the process which maximizes the profit of each agent. In order to incorporate more realistic situations, we also introduce an external field which changes in time. This time-varying external field represents any internal or external interference in the dynamics of the market. For the proper choice of model parameters, the competition between the interactions causes an intermittency dynamics and we find that the distribution of logarithmic return of price follows a power-law.

  7. An agent-based model to rural-urban migration analysis

    CERN Document Server

    Silveira, J J; Penna, T J P; Silveira, Jaylson J.; Espindola, Aquino L.

    2005-01-01

    In this paper we analyze the rural-urban migration phenomena as it is usually observed in economies which are in the early stages of industrialization. The analysis is conducted by means of a statistical mechanics approach which builds a computational agent-based model. Agents are placed on a lattice and the connections among them are described via an Ising like model. Simulations on this computational model show some emergent properties that are common in developing economies, such as a transitional dynamics characterized by continuous growth of urban population, followed by the equalization of expected wages between rural and urban sectors (Harris-Todaro equilibrium condition), urban concentration and increasing of per capita income.

  8. The role of taste affinity in agent-based models for social recommendation

    CERN Document Server

    Cimini, Giulio; Medo, Matus; Chen, Duanbing

    2013-01-01

    In the Internet era, online social media emerged as the main tool for sharing opinions and information among individuals. In this work we study an adaptive model of a social network where directed links connect users with similar tastes, and over which information propagates through social recommendation. Agent-based simulations of two different artificial settings for modeling user tastes are compared with patterns seen in real data, suggesting that users differing in their scope of interests is a more realistic assumption than users differing only in their particular interests. We further introduce an extensive set of similarity metrics based on users' past assessments, and evaluate their use in the given social recommendation model with both artificial simulations and real data. Superior recommendation performance is observed for similarity metrics that give preference to users with small scope---who thus act as selective filters in social recommendation.

  9. Agent-based model for the h-index - exact solution

    Science.gov (United States)

    Żogała-Siudem, Barbara; Siudem, Grzegorz; Cena, Anna; Gagolewski, Marek

    2016-01-01

    Hirsch's h-index is perhaps the most popular citation-based measure of scientific excellence. In 2013, Ionescu and Chopard proposed an agent-based model describing a process for generating publications and citations in an abstract scientific community [G. Ionescu, B. Chopard, Eur. Phys. J. B 86, 426 (2013)]. Within such a framework, one may simulate a scientist's activity, and - by extension - investigate the whole community of researchers. Even though the Ionescu and Chopard model predicts the h-index quite well, the authors provided a solution based solely on simulations. In this paper, we complete their results with exact, analytic formulas. What is more, by considering a simplified version of the Ionescu-Chopard model, we obtained a compact, easy to compute formula for the h-index. The derived approximate and exact solutions are investigated on a simulated and real-world data sets.

  10. An agent-based interaction model for Chinese personal income distribution

    Science.gov (United States)

    Zou, Yijiang; Deng, Weibing; Li, Wei; Cai, Xu

    2015-10-01

    The personal income distribution in China was studied by employing the data from China Household Income Projects (CHIP) between 1990 and 2002. It was observed that the low and middle income regions could be described by the log-normal law, while the large income region could be well fitted by the power law. To characterize these empirical findings, a stochastic interactive model with mean-field approach was discussed, and the analytic result shows that the wealth distribution is of the Pareto type. Then we explored the agent-based model on networks, in which the exchange of wealth among agents depends on their connectivity. Numerical results suggest that the wealth of agents would largely rely on their connectivity, and the Pareto index of the simulated wealth distributions is comparable to those of the empirical data. The Pareto behavior of the tails of the empirical wealth distributions is consistent with that of the 'mean-field' model, as well as numerical simulations.

  11. Agent-Based Model to Study and Quantify the Evolution Dynamics of Android Malware Infection

    Directory of Open Access Journals (Sweden)

    Juan Alegre-Sanahuja

    2014-01-01

    Full Text Available In the last years the number of malware Apps that the users download to their devices has risen. In this paper, we propose an agent-based model to quantify the Android malware infection evolution, modeling the behavior of the users and the different markets where the users may download Apps. The model predicts the number of infected smartphones depending on the type of malware. Additionally, we will estimate the cost that the users should afford when the malware is in their devices. We will be able to analyze which part is more critical: the users, giving indiscriminate permissions to the Apps or not protecting their devices with antivirus software, or the Android platform, due to the vulnerabilities of the Android devices that permit their rooted. We focus on the community of Valencia, Spain, although the obtained results can be extrapolated to other places where the number of Android smartphones remains fairly stable.

  12. Agent-Based Evacuation Model Incorporating Fire Scene and Building Geometry

    Institute of Scientific and Technical Information of China (English)

    TANG Fangqin; REN Aizhu

    2008-01-01

    A comprehensive description of the key factors affecting evacuations at fire scones is necessary for accurate simulations.An agent-based simulation model which incorporates the fire scene and the building geometry is developed using a fire dynamics simulator (FDS) based on the computational fluid dynamics and geographic information system (GIS) data to model the occupant response.The building entities are generated for FDS simulation while the spatial analysis on GIS data represents the occupant's knowledge of the building.The influence of the fire is based on a hazard assessment of the combustion products.The agent behavior and decisions are affected by environmental features and the fire field.A case study demonstrates that the evacuation model effectively simulates the coexistence and interactions of the major factors including occupants,building geometry,and fire disaster during the evacuation.The results can be used for the assessments of building designs regarding fire safety.

  13. Bounded Rational Managers Struggle with Talent Management - An Agent-based Modelling Approach

    DEFF Research Database (Denmark)

    Adamsen, Billy; Thomsen, Svend Erik

    and its denotative meaning floating, we propose that bounded rational managers base their decisions on a simple heuristic, i.e. selecting and cultivating individuals so that their capabilities resemble their own capabilities the most (Adamsen 2015). We model the consequences of this talent management...... of past success will provide failure rather than success in the future (Capelli.2008). Finally, we model the talent selection process either as a collective decision making process made by a group of managers or a decision process made by a single manager.It is argued that agent-based modeling is a useful....... The considered variables were: (a) decision makers’ attributes (capabilities and degree of bounded rationality), (b) characteristics of the sample where individuals are selected from (the level of capabilities and the dispersion thereof), (c) path-dependency of the organization’s success, and (d) the decision...

  14. An agent based multi-optional model for the diffusion of innovations

    Science.gov (United States)

    Laciana, Carlos E.; Oteiza-Aguirre, Nicolás

    2014-01-01

    We propose a model for the diffusion of several products competing in a common market based on the generalization of the Ising model of statistical mechanics (Potts model). Using an agent based implementation we analyze two problems: (i) a three options case, i.e. to adopt a product A, a product B, or non-adoption and (ii) a four option case, i.e. the adoption of product A, product B, both, or none. In the first case we analyze a launching strategy for one of the two products, which delays its launching with the objective of competing with improvements. Market shares reached by each product are then estimated at market saturation. Finally, simulations are carried out with varying degrees of social network topology, uncertainty, and population homogeneity.

  15. An Agent-Based Modeling Framework and Application for the Generic Nuclear Fuel Cycle

    Science.gov (United States)

    Gidden, Matthew J.

    Key components of a novel methodology and implementation of an agent-based, dynamic nuclear fuel cycle simulator, Cyclus , are presented. The nuclear fuel cycle is a complex, physics-dependent supply chain. To date, existing dynamic simulators have not treated constrained fuel supply, time-dependent, isotopic-quality based demand, or fuel fungibility particularly well. Utilizing an agent-based methodology that incorporates sophisticated graph theory and operations research techniques can overcome these deficiencies. This work describes a simulation kernel and agents that interact with it, highlighting the Dynamic Resource Exchange (DRE), the supply-demand framework at the heart of the kernel. The key agent-DRE interaction mechanisms are described, which enable complex entity interaction through the use of physics and socio-economic models. The translation of an exchange instance to a variant of the Multicommodity Transportation Problem, which can be solved feasibly or optimally, follows. An extensive investigation of solution performance and fidelity is then presented. Finally, recommendations for future users of Cyclus and the DRE are provided.

  16. Study of the attractor structure of an agent-based sociological model

    International Nuclear Information System (INIS)

    The Sznajd model is a sociophysics model that is based in the Potts model, and used for describing opinion propagation in a society. It employs an agent-based approach and interaction rules favouring pairs of agreeing agents. It has been successfully employed in modeling some properties and scale features of both proportional and majority elections (see for instance the works of A. T. Bernardes and R. N. Costa Filho), but its stationary states are always consensus states. In order to explain more complicated behaviours, we have modified the bounded confidence idea (introduced before in other opinion models, like the Deffuant model), with the introduction of prejudices and biases (we called this modification confidence rules), and have adapted it to the discrete Sznajd model. This generalized Sznajd model is able to reproduce almost all of the previous versions of the Sznajd model, by using appropriate choices of parameters. We solved the attractor structure of the resulting model in a mean-field approach and made Monte Carlo simulations in a Barabasi-Albert network. These simulations show great similarities with the mean-field, for the tested cases of 3 and 4 opinions. The dynamical systems approach that we devised allows for a deeper understanding of the potential of the Sznajd model as an opinion propagation model and can be easily extended to other models, like the voter model. Our modification of the bounded confidence rule can also be readily applied to other opinion propagation models.

  17. Developing an Agent-Based Model to Simulate Urban Land-Use Expansion (Case Study: Qazvin

    Directory of Open Access Journals (Sweden)

    F. Nourian

    2012-01-01

    Full Text Available Extended abstract1-IntroductionUrban land-use expansion is a challenging issue in developing countries. Increases in population as well as the immigration from the villages to the cities are the two major factors for that phenomenon. Those factors have reduced the influence of efforts that try to limit the cities’ boundaries. Thus, spatial planners always look for the models that simulate the expansion of urban land-uses and enable them to prevent unbalanced expansions of cities and guide the developments to the desired areas. Several models have been developed and evaluated for simulating urban land-use expansions. Despite the variety of the models, most of them have focused on simulating urban land-use expansions just around a city. Thus, the regional models that consider wider area are of primary importance.2- Theoretical basesIn this study a new agent-based model has been developed and implemented to simulate urban land-use expansion in Qazvin and Alborz regions of Qazvin state which have an area of 1620 square kilometers. In this model, land-use developers have been treated as agents that move in the landscape explicitly and assess the state of parcels for development. So, the environment of the model is raster. The agents are developed into five groups which have different aims. The agents may fall in competition to develop the same parcels. Moreover, due to the spatial essence of the problem, GIS were used to prepare the environment of agents’ movement and search and to aggregate and analyze the results.Two main steps can be recognized in this model: the Searching step and the Development step:Searching step: The agents are created and distributed in the districts. The selection of districts is probabilistic and is based on the primary probability of selection, assumed for districts. When agents go to the districts, at first they move randomly to the neighborhood of pre-developed areas. Wherever the agent starts its activities, it

  18. Agent-based modeling of endotoxin-induced acute inflammatory response in human blood leukocytes.

    Directory of Open Access Journals (Sweden)

    Xu Dong

    Full Text Available BACKGROUND: Inflammation is a highly complex biological response evoked by many stimuli. A persistent challenge in modeling this dynamic process has been the (nonlinear nature of the response that precludes the single-variable assumption. Systems-based approaches offer a promising possibility for understanding inflammation in its homeostatic context. In order to study the underlying complexity of the acute inflammatory response, an agent-based framework is developed that models the emerging host response as the outcome of orchestrated interactions associated with intricate signaling cascades and intercellular immune system interactions. METHODOLOGY/PRINCIPAL FINDINGS: An agent-based modeling (ABM framework is proposed to study the nonlinear dynamics of acute human inflammation. The model is implemented using NetLogo software. Interacting agents involve either inflammation-specific molecules or cells essential for the propagation of the inflammatory reaction across the system. Spatial orientation of molecule interactions involved in signaling cascades coupled with the cellular heterogeneity are further taken into account. The proposed in silico model is evaluated through its ability to successfully reproduce a self-limited inflammatory response as well as a series of scenarios indicative of the nonlinear dynamics of the response. Such scenarios involve either a persistent (noninfectious response or innate immune tolerance and potentiation effects followed by perturbations in intracellular signaling molecules and cascades. CONCLUSIONS/SIGNIFICANCE: The ABM framework developed in this study provides insight on the stochastic interactions of the mediators involved in the propagation of endotoxin signaling at the cellular response level. The simulation results are in accordance with our prior research effort associated with the development of deterministic human inflammation models that include transcriptional dynamics, signaling, and physiological

  19. Simulating the Reproductive Behavior of a Region’s Population with an Agent-Based Model

    Directory of Open Access Journals (Sweden)

    Valeriy Leonidovich Makarov

    2015-09-01

    Full Text Available The research analyses the impact of the inequality of demographic transition on socio-demographic characteristics of the regional population and on the dynamics of these characteristics. The study was conducted with the help of computer-based experiments (simulations, which was run on the original agent-based model. The model is an artificial society, and personal characteristics of its members are set so that they could represent age-demographic structure of a simulate region. The agents are divided into two subgroups, which differ in their reproductive strategy. The first group has traditional strategy with high birth rate. The second group has considerably lower birth rate, observed in the modern developed societies. The model uses stochastic approaches to imitate the principle processes of population growth: mortality and morbidity. Mortality is set according to age-sex specific mortality coefficients, which do not differ across the population as a whole. New agents (child births appear as a choice of agents – women of reproductive age, and the choice depends on the subgroup. The overall age and social structure of the region is aggregated across individual agents. A number of experiments has been carried out with the model utilization. This allowed forecasting the size and structure of the population of a given region. The results of the experiments have revealed that despite its simplicity, the developed agent-based model well predicts the initial conditions in the region (e.g. age-demographic and social structure. The model shows good fit in terms of estimating the dynamics of major characteristics of the population.

  20. Carbon emissions trading scheme exploration in China: A multi-agent-based model

    International Nuclear Information System (INIS)

    To develop a low-carbon economy, China launched seven pilot programs for carbon emissions trading (CET) in 2011 and plans to establish a nationwide CET mechanism in 2015. This paper formulated a multi-agent-based model to investigate the impacts of different CET designs in order to find the most appropriate one for China. The proposed bottom-up model includes all main economic agents in a general equilibrium framework. The simulation results indicate that (1) CET would effectively reduce carbon emissions, with a certain negative impact on the economy, (2) as for allowance allocation, the grandfathering rule is relatively moderate, while the benchmarking rule is more aggressive, (3) as for the carbon price, when the price level in the secondary CET market is regulated to be around RMB 40 per metric ton, a satisfactory emission mitigation effect can be obtained, (4) the penalty rate is suggested to be carefully designed to balance the economy development and mitigation effect, and (5) subsidy policy for energy technology improvement can effectively reduce carbon emissions without an additional negative impact on the economy. The results also indicate that the proposed novel model is a promising tool for CET policy making and analyses. -- Highlights: •A multi-agent-based model is proposed for carbon emissions trading (CET) in China. •Three agents are included: government, firms in different sectors and households. •The impacts of CET on the economy and environment in China are analyzed. •Different CET designs are simulated to find an appropriate policy for China. •Results confirm the effectiveness of the model and give helpful insights into CET design

  1. Evolving nutritional strategies in the presence of competition: a geometric agent-based model.

    Directory of Open Access Journals (Sweden)

    Alistair M Senior

    2015-03-01

    Full Text Available Access to nutrients is a key factor governing development, reproduction and ultimately fitness. Within social groups, contest-competition can fundamentally affect nutrient access, potentially leading to reproductive asymmetry among individuals. Previously, agent-based models have been combined with the Geometric Framework of nutrition to provide insight into how nutrition and social interactions affect one another. Here, we expand this modelling approach by incorporating evolutionary algorithms to explore how contest-competition over nutrient acquisition might affect the evolution of animal nutritional strategies. Specifically, we model tolerance of nutrient excesses and deficits when ingesting nutritionally imbalanced foods, which we term 'nutritional latitude'; a higher degree of nutritional latitude constitutes a higher tolerance of nutritional excess and deficit. Our results indicate that a transition between two alternative strategies occurs at moderate to high levels of competition. When competition is low, individuals display a low level of nutritional latitude and regularly switch foods in search of an optimum. When food is scarce and contest-competition is intense, high nutritional latitude appears optimal, and individuals continue to consume an imbalanced food for longer periods before attempting to switch to an alternative. However, the relative balance of nutrients within available foods also strongly influences at what levels of competition, if any, transitions between these two strategies occur. Our models imply that competition combined with reproductive skew in social groups can play a role in the evolution of diet breadth. We discuss how the integration of agent-based, nutritional and evolutionary modelling may be applied in future studies to further understand the evolution of nutritional strategies across social and ecological contexts.

  2. Building v/s Exploring Models: Comparing Learning of Evolutionary Processes through Agent-based Modeling

    Science.gov (United States)

    Wagh, Aditi

    Two strands of work motivate the three studies in this dissertation. Evolutionary change can be viewed as a computational complex system in which a small set of rules operating at the individual level result in different population level outcomes under different conditions. Extensive research has documented students' difficulties with learning about evolutionary change (Rosengren et al., 2012), particularly in terms of levels slippage (Wilensky & Resnick, 1999). Second, though building and using computational models is becoming increasingly common in K-12 science education, we know little about how these two modalities compare. This dissertation adopts agent-based modeling as a representational system to compare these modalities in the conceptual context of micro-evolutionary processes. Drawing on interviews, Study 1 examines middle-school students' productive ways of reasoning about micro-evolutionary processes to find that the specific framing of traits plays a key role in whether slippage explanations are cued. Study 2, which was conducted in 2 schools with about 150 students, forms the crux of the dissertation. It compares learning processes and outcomes when students build their own models or explore a pre-built model. Analysis of Camtasia videos of student pairs reveals that builders' and explorers' ways of accessing rules, and sense-making of observed trends are of a different character. Builders notice rules through available blocks-based primitives, often bypassing their enactment while explorers attend to rules primarily through the enactment. Moreover, builders' sense-making of observed trends is more rule-driven while explorers' is more enactment-driven. Pre and posttests reveal that builders manifest a greater facility with accessing rules, providing explanations manifesting targeted assembly. Explorers use rules to construct explanations manifesting non-targeted assembly. Interviews reveal varying degrees of shifts away from slippage in both

  3. Agent based model of effects of task allocation strategies in flat organizations

    Science.gov (United States)

    Sobkowicz, Pawel

    2016-09-01

    A common practice in many organizations is to pile the work on the best performers. It is easy to implement by the management and, despite the apparent injustice, appears to be working in many situations. In our work we present a simple agent based model, constructed to simulate this practice and to analyze conditions under which the overall efficiency of the organization (for example measured by the backlog of unresolved issues) breaks down, due to the cumulative effect of the individual overloads. The model confirms that the strategy mentioned above is, indeed, rational: it leads to better global results than an alternative one, using equal workload distribution among all workers. The presented analyses focus on the behavior of the organizations close to the limit of the maximum total throughput and provide results for the growth of the unprocessed backlog in several situations, as well as suggestions related to avoiding such buildup.

  4. Agent-based model for the h-index - Exact solution

    CERN Document Server

    Żogała-Siudem, Barbara; Cena, Anna; Gagolewski, Marek

    2015-01-01

    The Hirsch's $h$-index is perhaps the most popular citation-based measure of the scientific excellence. In 2013 G. Ionescu and B. Chopard proposed an agent-based model for this index to describe a publications and citations generation process in an abstract scientific community. With such an approach one can simulate a single scientist's activity, and by extension investigate the whole community of researchers. Even though this approach predicts quite well the $h$-index from bibliometric data, only a solution based on simulations was given. In this paper, we complete their results with exact, analytic formulas. What is more, due to our exact solution we are able to simplify the Ionescu-Chopard model which allows us to obtain a compact formula for $h$-index. Moreover, a simulation study designed to compare both, approximated and exact, solutions is included. The last part of this paper presents evaluation of the obtained results on a real-word data set.

  5. A Simple Agent Based Model for Detecting Abnormal Event Patterns in a Distributed Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Muktikanta Sa, Manas Ranjan Nayak & Amiya Kumar Rath

    2011-08-01

    Full Text Available Wireless Sensor networks (WSN is a promising technology for current as well asfuture. There is vast use of WSN in different fields like military surveillance andtarget tracking, traffic management, weather forecasting, habitat monitoring,designing smart home, structural and seismic monitoring, etc. For successapplication of ubiquitous WSN it is important to maintain the basic security, bothfrom external and internal attacks else entire network may collapse. Maintainingsecurity in WSN network is not a simple job just like securing wireless networksbecause sensor nodes are deployed in randomize manner. Hence majorchallenges in WSN are security. In this paper we have discussed differentattacks in WSN and how these attacks are efficiently detected by using our agentbased model. Our model identifies the abnormal event pattern sensor nodes in alargely deployed distributed sensor network under a common anomaly detectionframework which will be designed by agent based learning and distributed datamining technique.

  6. Holistic flood risk assessment using agent-based modelling: the case of Sint Maarten Island

    Science.gov (United States)

    Abayneh Abebe, Yared; Vojinovic, Zoran; Nikolic, Igor; Hammond, Michael; Sanchez, Arlex; Pelling, Mark

    2015-04-01

    Floods in coastal regions are regarded as one of the most dangerous and harmful disasters. Though commonly referred to as natural disasters, coastal floods are also attributable to various social, economic, historical and political issues. Rapid urbanisation in coastal areas combined with climate change and poor governance can lead to a significant increase in the risk of pluvial flooding coinciding with fluvial and coastal flooding posing a greater risk of devastation in coastal communities. Disasters that can be triggered by hydro-meteorological events are interconnected and interrelated with both human activities and natural processes. They, therefore, require holistic approaches to help understand their complexity in order to design and develop adaptive risk management approaches that minimise social and economic losses and environmental impacts, and increase resilience to such events. Being located in the North Atlantic Ocean, Sint Maarten is frequently subjected to hurricanes. In addition, the stormwater catchments and streams on Sint Maarten have several unique characteristics that contribute to the severity of flood-related impacts. Urban environments are usually situated in low-lying areas, with little consideration for stormwater drainage, and as such are subject to flash flooding. Hence, Sint Maarten authorities drafted policies to minimise the risk of flood-related disasters on the island. In this study, an agent-based model is designed and applied to understand the implications of introduced policies and regulations, and to understand how different actors' behaviours influence the formation, propagation and accumulation of flood risk. The agent-based model built for this study is based on the MAIA meta-model, which helps to decompose, structure and conceptualize socio-technical systems with an agent-oriented perspective, and is developed using the NetLogo simulation environment. The agents described in this model are households and businesses, and

  7. Investigating mathematical models of immuno-interactions with early-stage cancer under an agent-based modelling perspective

    OpenAIRE

    Figueredo, Grazziela P.; Siebers, Peer-Olaf; Aickelin, Uwe

    2013-01-01

    Many advances in research regarding immuno-interactions with cancer were developed with the help of ordinary differential equation (ODE) models. These models, however, are not effectively capable of representing problems involving individual localisation, memory and emerging properties, which are common characteristics of cells and molecules of the immune system. Agent-based modelling and simulation is an alternative paradigm to ODE models that overcomes these limitations. In this paper we in...

  8. Physics and financial economics (1776–2014): puzzles, Ising and agent-based models

    International Nuclear Information System (INIS)

    This short review presents a selected history of the mutual fertilization between physics and economics—from Isaac Newton and Adam Smith to the present. The fundamentally different perspectives embraced in theories developed in financial economics compared with physics are dissected with the examples of the volatility smile and of the excess volatility puzzle. The role of the Ising model of phase transitions to model social and financial systems is reviewed, with the concepts of random utilities and the logit model as the analog of the Boltzmann factor in statistical physics. Recent extensions in terms of quantum decision theory are also covered. A wealth of models are discussed briefly that build on the Ising model and generalize it to account for the many stylized facts of financial markets. A summary of the relevance of the Ising model and its extensions is provided to account for financial bubbles and crashes. The review would be incomplete if it did not cover the dynamical field of agent-based models (ABMs), also known as computational economic models, of which the Ising-type models are just special ABM implementations. We formulate the ‘Emerging Intelligence Market Hypothesis’ to reconcile the pervasive presence of ‘noise traders’ with the near efficiency of financial markets. Finally, we note that evolutionary biology, more than physics, is now playing a growing role to inspire models of financial markets. (key issues reviews)

  9. Physics and financial economics (1776-2014): puzzles, Ising and agent-based models.

    Science.gov (United States)

    Sornette, Didier

    2014-06-01

    This short review presents a selected history of the mutual fertilization between physics and economics--from Isaac Newton and Adam Smith to the present. The fundamentally different perspectives embraced in theories developed in financial economics compared with physics are dissected with the examples of the volatility smile and of the excess volatility puzzle. The role of the Ising model of phase transitions to model social and financial systems is reviewed, with the concepts of random utilities and the logit model as the analog of the Boltzmann factor in statistical physics. Recent extensions in terms of quantum decision theory are also covered. A wealth of models are discussed briefly that build on the Ising model and generalize it to account for the many stylized facts of financial markets. A summary of the relevance of the Ising model and its extensions is provided to account for financial bubbles and crashes. The review would be incomplete if it did not cover the dynamical field of agent-based models (ABMs), also known as computational economic models, of which the Ising-type models are just special ABM implementations. We formulate the 'Emerging Intelligence Market Hypothesis' to reconcile the pervasive presence of 'noise traders' with the near efficiency of financial markets. Finally, we note that evolutionary biology, more than physics, is now playing a growing role to inspire models of financial markets.

  10. Physics and financial economics (1776-2014): puzzles, Ising and agent-based models

    Science.gov (United States)

    Sornette, Didier

    2014-06-01

    This short review presents a selected history of the mutual fertilization between physics and economics—from Isaac Newton and Adam Smith to the present. The fundamentally different perspectives embraced in theories developed in financial economics compared with physics are dissected with the examples of the volatility smile and of the excess volatility puzzle. The role of the Ising model of phase transitions to model social and financial systems is reviewed, with the concepts of random utilities and the logit model as the analog of the Boltzmann factor in statistical physics. Recent extensions in terms of quantum decision theory are also covered. A wealth of models are discussed briefly that build on the Ising model and generalize it to account for the many stylized facts of financial markets. A summary of the relevance of the Ising model and its extensions is provided to account for financial bubbles and crashes. The review would be incomplete if it did not cover the dynamical field of agent-based models (ABMs), also known as computational economic models, of which the Ising-type models are just special ABM implementations. We formulate the ‘Emerging Intelligence Market Hypothesis’ to reconcile the pervasive presence of ‘noise traders’ with the near efficiency of financial markets. Finally, we note that evolutionary biology, more than physics, is now playing a growing role to inspire models of financial markets.

  11. Physics and financial economics (1776-2014): puzzles, Ising and agent-based models.

    Science.gov (United States)

    Sornette, Didier

    2014-06-01

    This short review presents a selected history of the mutual fertilization between physics and economics--from Isaac Newton and Adam Smith to the present. The fundamentally different perspectives embraced in theories developed in financial economics compared with physics are dissected with the examples of the volatility smile and of the excess volatility puzzle. The role of the Ising model of phase transitions to model social and financial systems is reviewed, with the concepts of random utilities and the logit model as the analog of the Boltzmann factor in statistical physics. Recent extensions in terms of quantum decision theory are also covered. A wealth of models are discussed briefly that build on the Ising model and generalize it to account for the many stylized facts of financial markets. A summary of the relevance of the Ising model and its extensions is provided to account for financial bubbles and crashes. The review would be incomplete if it did not cover the dynamical field of agent-based models (ABMs), also known as computational economic models, of which the Ising-type models are just special ABM implementations. We formulate the 'Emerging Intelligence Market Hypothesis' to reconcile the pervasive presence of 'noise traders' with the near efficiency of financial markets. Finally, we note that evolutionary biology, more than physics, is now playing a growing role to inspire models of financial markets. PMID:24875470

  12. Opening the black box—Development, testing and documentation of a mechanistically rich agent-based model

    DEFF Research Database (Denmark)

    Topping, Chris J.; Høye, Toke; Olesen, Carsten Riis

    2010-01-01

    Although increasingly widely used in biology, complex adaptive simulation models such as agent-based models have been criticised for being difficult to communicate and test. This study demonstrates the application of pattern-oriented model testing, and a novel documentation procedure to present...... a detailed agent-based model of the European brown hare, a species in widespread decline in Europe. The model was built based on available literature data, using multiple field data patterns from an island hare population study to guide model development. A general and widely applicable approach...... to the pattern-oriented protocol for testing and developing ecological models of this kind was defined together with the development of the ODdox documentation protocol, a combination of the current ODD protocol for describing agent-based models and source-code documentation. The result is a detailed and yet...

  13. Computational Research on Mobile Pastoralism Using Agent-Based Modeling and Satellite Imagery.

    Directory of Open Access Journals (Sweden)

    Takuto Sakamoto

    Full Text Available Dryland pastoralism has long attracted considerable attention from researchers in diverse fields. However, rigorous formal study is made difficult by the high level of mobility of pastoralists as well as by the sizable spatio-temporal variability of their environment. This article presents a new computational approach for studying mobile pastoralism that overcomes these issues. Combining multi-temporal satellite images and agent-based modeling allows a comprehensive examination of pastoral resource access over a realistic dryland landscape with unpredictable ecological dynamics. The article demonstrates the analytical potential of this approach through its application to mobile pastoralism in northeast Nigeria. Employing more than 100 satellite images of the area, extensive simulations are conducted under a wide array of circumstances, including different land-use constraints. The simulation results reveal complex dependencies of pastoral resource access on these circumstances along with persistent patterns of seasonal land use observed at the macro level.

  14. On religion and language evolutions seen through mathematical and agent based models

    CERN Document Server

    Ausloos, M

    2011-01-01

    (shortened version) Religions and languages are social variables, like age, sex, wealth or political opinions, to be studied like any other organizational parameter. In fact, religiosity is one of the most important sociological aspects of populations. Languages are also a characteristics of the human kind. New religions, new languages appear though others disappear. All religions and languages evolve when they adapt to the society developments. On the other hand, the number of adherents of a given religion, the number of persons speaking a language is not fixed. Several questions can be raised. E.g. from a macroscopic point of view : How many religions/languages exist at a given time? What is their distribution? What is their life time? How do they evolve?. From a microscopic view point: can one invent agent based models to describe macroscopic aspects? Does it exist simple evolution equations? It is intuitively accepted, but also found through from statistical analysis of the frequency distribution that an ...

  15. Computational Research on Mobile Pastoralism Using Agent-Based Modeling and Satellite Imagery.

    Science.gov (United States)

    Sakamoto, Takuto

    2016-01-01

    Dryland pastoralism has long attracted considerable attention from researchers in diverse fields. However, rigorous formal study is made difficult by the high level of mobility of pastoralists as well as by the sizable spatio-temporal variability of their environment. This article presents a new computational approach for studying mobile pastoralism that overcomes these issues. Combining multi-temporal satellite images and agent-based modeling allows a comprehensive examination of pastoral resource access over a realistic dryland landscape with unpredictable ecological dynamics. The article demonstrates the analytical potential of this approach through its application to mobile pastoralism in northeast Nigeria. Employing more than 100 satellite images of the area, extensive simulations are conducted under a wide array of circumstances, including different land-use constraints. The simulation results reveal complex dependencies of pastoral resource access on these circumstances along with persistent patterns of seasonal land use observed at the macro level. PMID:26963526

  16. Re-Examining of Moffitt's Theory of Delinquency through Agent Based Modeling.

    Directory of Open Access Journals (Sweden)

    Jia Ning Leaw

    Full Text Available Moffitt's theory of delinquency suggests that at-risk youths can be divided into two groups, the adolescence- limited group and the life-course-persistent group, predetermined at a young age, and social interactions between these two groups become important during the adolescent years. We built an agent-based model based on the microscopic interactions Moffitt described: (i a maturity gap that dictates (ii the cost and reward of antisocial behavior, and (iii agents imitating the antisocial behaviors of others more successful than themselves, to find indeed the two groups emerging in our simulations. Moreover, through an intervention simulation where we moved selected agents from one social network to another, we also found that the social network plays an important role in shaping the life course outcome.

  17. The Evolution of ICT Markets: An Agent-Based Model on Complex Networks

    Science.gov (United States)

    Zhao, Liangjie; Wu, Bangtao; Chen, Zhong; Li, Li

    Information and communication technology (ICT) products exhibit positive network effects.The dynamic process of ICT markets evolution has two intrinsic characteristics: (1) customers are influenced by each others’ purchasing decision; (2) customers are intelligent agents with bounded rationality.Guided by complex systems theory, we construct an agent-based model and simulate on complex networks to examine how the evolution can arise from the interaction of customers, which occur when they make expectations about the future installed base of a product by the fraction of neighbors who are using the same product in his personal network.We demonstrate that network effects play an important role in the evolution of markets share, which make even an inferior product can dominate the whole market.We also find that the intensity of customers’ communication can influence whether the best initial strategy for firms is to improve product quality or expand their installed base.

  18. Agent-based models for the emergence and evolution of grammar.

    Science.gov (United States)

    Steels, Luc

    2016-08-19

    Human languages are extraordinarily complex adaptive systems. They feature intricate hierarchical sound structures, are able to express elaborate meanings and use sophisticated syntactic and semantic structures to relate sound to meaning. What are the cognitive mechanisms that speakers and listeners need to create and sustain such a remarkable system? What is the collective evolutionary dynamics that allows a language to self-organize, become more complex and adapt to changing challenges in expressive power? This paper focuses on grammar. It presents a basic cycle observed in the historical language record, whereby meanings move from lexical to syntactic and then to a morphological mode of expression before returning to a lexical mode, and discusses how we can discover and validate mechanisms that can cause these shifts using agent-based models.This article is part of the themed issue 'The major synthetic evolutionary transitions'. PMID:27431525

  19. Information, Meaning and Eigenforms: In the Light of Sociology, Agent-Based Modeling and AI

    Directory of Open Access Journals (Sweden)

    Manfred Füllsack

    2012-08-01

    Full Text Available The paper considers the relation of Shannon-type information to those semantic and hermeneutic aspects of communication, which are often referred to as meaning. It builds on considerations of Talcott Parsons, Niklas Luhmann and Robert K. Logan and relates them to an agent-based model that reproduces key aspects of the Talking Head experiment by Luc Steels. The resulting insights seem to give reason to regard information and meaning not as qualitatively different entities, but as interrelated forms of order that emerge in the interaction of autonomous (self-referentially closed agents. Although on first sight, this way of putting information and meaning into a constructivist framework seems to open possibilities to conceive meaning in terms of Shannon-information, it also suggests a re-conceptualization of information in terms of what cybernetics calls Eigenform in order to do justice to its dynamic interrelation with meaning.

  20. Agent-based model of laser hair removal: A treatment optimization and patient education tool

    Directory of Open Access Journals (Sweden)

    Eapen Bell

    2009-01-01

    Full Text Available Background: Tracking of various parameters associated with laser hair removal is tedious and time consuming. The currently available mathematical models are not simple enough for physicians to be used as a treatment optimization and patient education tool. Aim: The aim of the study was to develop a mathematical model for laser hair removal using agent-based modeling and to make a user-friendly simulation environment. Methods: The model was created using NetLogo. The hairs were modeled as agents oscillating between anagen and telogen. The variables were assigned based on published data whenever possible and the various paths the agent could take were coded as conditional statements. The improvement was assessed using an arbitrary index which takes into account the mean diameter and pigmentation along with the number and length of hairs visible above the surface. Few of the commonly encountered scenarios were simulated using the model. Results: The model is made freely available online (http://www.gulfdoctor.net/model/lhr.htm. Limited number of simulations performed indicated that an eight-week gap between laser sessions may be more effective than a four-week gap. Conclusions: The simulation provides a reliable tool for treatment optimization and patient education as obtaining relevant clinical data is slow and labor-intensive. Its visual interface and online availability makes it useful for everyday use.

  1. Variance in system dynamics and agent based modelling using the SIR model of infectious diseases

    OpenAIRE

    Ahmed, Aslam; Greensmith, Julie; Aickelin, Uwe

    2012-01-01

    Classical deterministic simulations of epidemiological processes, such as those based on System Dynamics, produce a single result based on a fixed set of input parameters with no variance between simulations. Input parameters are subsequently modified on these simulations using Monte-Carlo methods, to understand how changes in the input parameters affect the spread of results for the simulation. Agent Based simulations are able to produce different output results on each run based on knowledg...

  2. An agent-based hydroeconomic model to evaluate water policies in Jordan

    Science.gov (United States)

    Yoon, J.; Gorelick, S.

    2014-12-01

    Modern water systems can be characterized by a complex network of institutional and private actors that represent competing sectors and interests. Identifying solutions to enhance water security in such systems calls for analysis that can adequately account for this level of complexity and interaction. Our work focuses on the development of a hierarchical, multi-agent, hydroeconomic model that attempts to realistically represent complex interactions between hydrologic and multi-faceted human systems. The model is applied to Jordan, one of the most water-poor countries in the world. In recent years, the water crisis in Jordan has escalated due to an ongoing drought and influx of refugees from regional conflicts. We adopt a modular approach in which biophysical modules simulate natural and engineering phenomena, and human modules represent behavior at multiple scales of decision making. The human modules employ agent-based modeling, in which agents act as autonomous decision makers at the transboundary, state, organizational, and user levels. A systematic nomenclature and conceptual framework is used to characterize model agents and modules. Concepts from the Unified Modeling Language (UML) are adopted to promote clear conceptualization of model classes and process sequencing, establishing a foundation for full deployment of the integrated model in a scalable object-oriented programming environment. Although the framework is applied to the Jordanian water context, it is generalizable to other regional human-natural freshwater supply systems.

  3. Comparing Simulation Output Accuracy of Discrete Event and Agent Based Models: A Quantitive Approach

    CERN Document Server

    Majid, Mazlina Abdul; Siebers, Peer-Olaf

    2010-01-01

    In our research we investigate the output accuracy of discrete event simulation models and agent based simulation models when studying human centric complex systems. In this paper we focus on human reactive behaviour as it is possible in both modelling approaches to implement human reactive behaviour in the model by using standard methods. As a case study we have chosen the retail sector, and here in particular the operations of the fitting room in the women wear department of a large UK department store. In our case study we looked at ways of determining the efficiency of implementing new management policies for the fitting room operation through modelling the reactive behaviour of staff and customers of the department. First, we have carried out a validation experiment in which we compared the results from our models to the performance of the real system. This experiment also allowed us to establish differences in output accuracy between the two modelling methids. In a second step a multi-scenario experimen...

  4. An agent-based model to study market penetration of plug-in hybrid electric vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Eppstein, Margaret J., E-mail: Maggie.Eppstein@uvm.edu [Department of Computer Science, University of Vermont, Burlington, VT 05405 (United States); Grover, David K.; Marshall, Jeffrey S.; Rizzo, Donna M. [School of Engineering, University of Vermont, Burlington, VT 05405 (United States)

    2011-06-15

    A spatially explicit agent-based vehicle consumer choice model is developed to explore sensitivities and nonlinear interactions between various potential influences on plug-in hybrid vehicle (PHEV) market penetration. The model accounts for spatial and social effects (including threshold effects, homophily, and conformity) and media influences. Preliminary simulations demonstrate how such a model could be used to identify nonlinear interactions among potential leverage points, inform policies affecting PHEV market penetration, and help identify future data collection necessary to more accurately model the system. We examine sensitivity of the model to gasoline prices, to accuracy in estimation of fuel costs, to agent willingness to adopt the PHEV technology, to PHEV purchase price and rebates, to PHEV battery range, and to heuristic values related to gasoline usage. Our simulations indicate that PHEV market penetration could be enhanced significantly by providing consumers with ready estimates of expected lifetime fuel costs associated with different vehicles (e.g., on vehicle stickers), and that increases in gasoline prices could nonlinearly magnify the impact on fleet efficiency. We also infer that a potential synergy from a gasoline tax with proceeds is used to fund research into longer-range lower-cost PHEV batteries. - Highlights: > We model consumer agents to study potential market penetration of PHEVs. > The model accounts for spatial, social, and media effects. > We identify interactions among potential leverage points that could inform policy. > Consumer access to expected lifetime fuel costs may enhance PHEV market penetration. > Increasing PHEV battery range has synergistic effects on fleet efficiency.

  5. Agent-based modeling of hyporheic dissolved organic carbon transport and transformation

    Science.gov (United States)

    Gabrielsen, P. J.; Wilson, J. L.; Pullin, M.

    2011-12-01

    Dissolved organic carbon (DOC) is a complex suite of organic compounds present in natural ecosystems, and is particularly studied in river and stream systems. The hyporheic zone (HZ), a region of surface water-shallow groundwater exchange, has been identified as a hotspot of DOC processing and is generally regarded as a net sink of organic matter. More recent studies into stream DOC have shifted to examining DOC quality rather than bulk quantity. DOC quality variability has been linked to hydrologic and climatic variability, both focuses of current climate change research. A new agent-based model in the NetLogo modeling environment couples hydrologic transport with chemical and biological transformation of DOC to simulate changing DOC quality in hyporheic flow. A pore-scale model implements a Lattice Boltzmann fluid dynamic model and surficial interactions to simulate sorption and microbial uptake. Upscaled to a stream meander scale, this model displays spatial variation and evolution of DOC quality. Model output metrics are correlated to field sample analytical results from a hyporheic meander of the East Fork Jemez River, Sandoval Co., NM.

  6. BSim: an agent-based tool for modeling bacterial populations in systems and synthetic biology.

    Science.gov (United States)

    Gorochowski, Thomas E; Matyjaszkiewicz, Antoni; Todd, Thomas; Oak, Neeraj; Kowalska, Kira; Reid, Stephen; Tsaneva-Atanasova, Krasimira T; Savery, Nigel J; Grierson, Claire S; di Bernardo, Mario

    2012-01-01

    Large-scale collective behaviors such as synchronization and coordination spontaneously arise in many bacterial populations. With systems biology attempting to understand these phenomena, and synthetic biology opening up the possibility of engineering them for our own benefit, there is growing interest in how bacterial populations are best modeled. Here we introduce BSim, a highly flexible agent-based computational tool for analyzing the relationships between single-cell dynamics and population level features. BSim includes reference implementations of many bacterial traits to enable the quick development of new models partially built from existing ones. Unlike existing modeling tools, BSim fully considers spatial aspects of a model allowing for the description of intricate micro-scale structures, enabling the modeling of bacterial behavior in more realistic three-dimensional, complex environments. The new opportunities that BSim opens are illustrated through several diverse examples covering: spatial multicellular computing, modeling complex environments, population dynamics of the lac operon, and the synchronization of genetic oscillators. BSim is open source software that is freely available from http://bsim-bccs.sf.net and distributed under the Open Source Initiative (OSI) recognized MIT license. Developer documentation and a wide range of example simulations are also available from the website. BSim requires Java version 1.6 or higher. PMID:22936991

  7. On Mechanism, Process and Polity: An Agent-Based Modeling and Simulation Approach

    Directory of Open Access Journals (Sweden)

    Camelia Florela Voinea

    2014-07-01

    Full Text Available The present approach provides a theoretical account of political culture-based modeling of political change phenomena. Our approach is an agent-based simulation model inspired by a social-psychological account of the relation between the individual agents (citizens and the polity. It includes political culture as a fundamental modeling dimension. On this background, we reconsider the operational definitions of agent, mechanism, process, and polity so as to specify the role they play in the modeling of political change phenomena. We evaluate our previous experimental simulation experience in corruption emergence and political attitude change. The paper approaches the artificial polity as a political culture-based model of a body politic. It involves political culture concepts to account for the complexity of domestic political phenomena, going from political attitude change at the individual level up to major political change at the societal level. Architecture, structure, unit of interaction, generative mechanisms and processes are described. Both conceptual and experimental issues are described so as to highlight the differences between the simulation models of society and polity.

  8. On Mechanism, Process and Polity: An Agent-Based Modeling and Simulation Approach

    Directory of Open Access Journals (Sweden)

    Voinea, Camelia Florela

    2014-07-01

    Full Text Available The present approach provides a theoretical account of political culture-based modeling of political change phenomena. Our approach is an agent-based simulation model inspired by a social-psychological account of the relation between the individual agents (citizens and the polity. It includes political culture as a fundamental modeling dimension. On this background, we reconsider the operational definitions of agent, mechanism, process, and polity so as to specify the role they play in the modeling of political change phenomena. We evaluate our previous experimental simulation experience in corruption emergence and political attitude change. The paper approaches the artificial polity as a political culture-based model of a body politic. It involves political culture concepts to account for the complexity of domestic political phenomena, going from political attitude change at the individual level up to major political change at the societal level. Architecture, structure, unit of interaction, generative mechanisms and processes are described. Both conceptual and experimental issues are described so as to highlight the differences between the simulation models of society and polity.  

  9. BSim: an agent-based tool for modeling bacterial populations in systems and synthetic biology.

    Directory of Open Access Journals (Sweden)

    Thomas E Gorochowski

    Full Text Available Large-scale collective behaviors such as synchronization and coordination spontaneously arise in many bacterial populations. With systems biology attempting to understand these phenomena, and synthetic biology opening up the possibility of engineering them for our own benefit, there is growing interest in how bacterial populations are best modeled. Here we introduce BSim, a highly flexible agent-based computational tool for analyzing the relationships between single-cell dynamics and population level features. BSim includes reference implementations of many bacterial traits to enable the quick development of new models partially built from existing ones. Unlike existing modeling tools, BSim fully considers spatial aspects of a model allowing for the description of intricate micro-scale structures, enabling the modeling of bacterial behavior in more realistic three-dimensional, complex environments. The new opportunities that BSim opens are illustrated through several diverse examples covering: spatial multicellular computing, modeling complex environments, population dynamics of the lac operon, and the synchronization of genetic oscillators. BSim is open source software that is freely available from http://bsim-bccs.sf.net and distributed under the Open Source Initiative (OSI recognized MIT license. Developer documentation and a wide range of example simulations are also available from the website. BSim requires Java version 1.6 or higher.

  10. Dynamics of bloggers’ communities: Bipartite networks from empirical data and agent-based modeling

    Science.gov (United States)

    Mitrović, Marija; Tadić, Bosiljka

    2012-11-01

    We present an analysis of the empirical data and the agent-based modeling of the emotional behavior of users on the Web portals where the user interaction is mediated by posted comments, like Blogs and Diggs. We consider the dataset of discussion-driven popular Diggs, in which all comments are screened by machine-learning emotion detection in the text, to determine positive and negative valence (attractiveness and aversiveness) of each comment. By mapping the data onto a suitable bipartite network, we perform an analysis of the network topology and the related time-series of the emotional comments. The agent-based model is then introduced to simulate the dynamics and to capture the emergence of the emotional behaviors and communities. The agents are linked to posts on a bipartite network, whose structure evolves through their actions on the posts. The emotional states (arousal and valence) of each agent fluctuate in time, subject to the current contents of the posts to which the agent is exposed. By an agent’s action on a post its current emotions are transferred to the post. The model rules and the key parameters are inferred from the considered empirical data to ensure their realistic values and mutual consistency. The model assumes that the emotional arousal over posts drives the agent’s action. The simulations are preformed for the case of constant flux of agents and the results are analyzed in full analogy with the empirical data. The main conclusions are that the emotion-driven dynamics leads to long-range temporal correlations and emergent networks with community structure, that are comparable with the ones in the empirical system of popular posts. In view of pure emotion-driven agents actions, this type of comparisons provide a quantitative measure for the role of emotions in the dynamics on real blogs. Furthermore, the model reveals the underlying mechanisms which relate the post popularity with the emotion dynamics and the prevalence of negative

  11. Quantitative Agent Based Model of Opinion Dynamics: Polish Elections of 2015.

    Science.gov (United States)

    Sobkowicz, Pawel

    2016-01-01

    We present results of an abstract, agent based model of opinion dynamics simulations based on the emotion/information/opinion (E/I/O) approach, applied to a strongly polarized society, corresponding to the Polish political scene between 2005 and 2015. Under certain conditions the model leads to metastable coexistence of two subcommunities of comparable size (supporting the corresponding opinions)-which corresponds to the bipartisan split found in Poland. Spurred by the recent breakdown of this political duopoly, which occurred in 2015, we present a model extension that describes both the long term coexistence of the two opposing opinions and a rapid, transitory change due to the appearance of a third party alternative. We provide quantitative comparison of the model with the results of polls and elections in Poland, testing the assumptions related to the modeled processes and the parameters used in the simulations. It is shown, that when the propaganda messages of the two incumbent parties differ in emotional tone, the political status quo may be unstable. The asymmetry of the emotions within the support bases of the two parties allows one of them to be 'invaded' by a newcomer third party very quickly, while the second remains immune to such invasion. PMID:27171226

  12. Quantitative Agent Based Model of Opinion Dynamics: Polish Elections of 2015.

    Directory of Open Access Journals (Sweden)

    Pawel Sobkowicz

    Full Text Available We present results of an abstract, agent based model of opinion dynamics simulations based on the emotion/information/opinion (E/I/O approach, applied to a strongly polarized society, corresponding to the Polish political scene between 2005 and 2015. Under certain conditions the model leads to metastable coexistence of two subcommunities of comparable size (supporting the corresponding opinions-which corresponds to the bipartisan split found in Poland. Spurred by the recent breakdown of this political duopoly, which occurred in 2015, we present a model extension that describes both the long term coexistence of the two opposing opinions and a rapid, transitory change due to the appearance of a third party alternative. We provide quantitative comparison of the model with the results of polls and elections in Poland, testing the assumptions related to the modeled processes and the parameters used in the simulations. It is shown, that when the propaganda messages of the two incumbent parties differ in emotional tone, the political status quo may be unstable. The asymmetry of the emotions within the support bases of the two parties allows one of them to be 'invaded' by a newcomer third party very quickly, while the second remains immune to such invasion.

  13. CACM: A New Coordination Model in Mobile Agent-Based Information Retrieval Applications

    Institute of Scientific and Technical Information of China (English)

    TANGXinhuai; ZHANGYaying; YAOYinxiong; YOUJinyuan

    2005-01-01

    In mobile agent systems, an application may be composed of several mobile agents that cooperatively perform a task. Multiple mobile agents need to communicate and interact with each other to accomplish their cooperative goal. Coordination model aims to provide solutions to interactions between concurrent activities, hiding the computing details and focusing on interaction between activities. A Context-aware coordination model (CACM), which combines mobility and coordination, is proposed for mobile agent applications, i.e. in mobile agent based information retrieval applications. The context-aware coordination model transfers interactions between agents from globally coupling interactions to locally uncoupling tuple space interactions. In addition, programmable tuple space is adopted to solve the problems of context-aware coordination introduced by mobility and data heterogeneity in mobile agent systems. Furthermore, environment specific and application specific coordination policy can be integrated into the programmable tuple space for customized requirements. Finally an application sample system-information retrieval in mobile agent applications is carried out to test the performance of the proposed model.

  14. Agent-based organizational modelling for analysis of safety culture at an air navigation service provider

    International Nuclear Information System (INIS)

    Assessment of safety culture is done predominantly by questionnaire-based studies, which tend to reveal attitudes on immaterial characteristics (values, beliefs, norms). There is a need for a better understanding of the implications of the material aspects of an organization (structures, processes, etc.) for safety culture and their interactions with the immaterial characteristics. This paper presents a new agent-based organizational modelling approach for integrated and systematic evaluation of material and immaterial characteristics of socio-technical organizations in safety culture analysis. It uniquely considers both the formal organization and the value- and belief-driven behaviour of individuals in the organization. Results are presented of a model for safety occurrence reporting at an air navigation service provider. Model predictions consistent with questionnaire-based results are achieved. A sensitivity analysis provides insight in organizational factors that strongly influence safety culture indicators. The modelling approach can be used in combination with attitude-focused safety culture research, towards an integrated evaluation of material and immaterial characteristics of socio-technical organizations. By using this approach an organization is able to gain a deeper understanding of causes of diverse problems and inefficiencies both in the formal organization and in the behaviour of organizational agents, and to systematically identify and evaluate improvement options.

  15. An agent-based model of dialect evolution in killer whales.

    Science.gov (United States)

    Filatova, Olga A; Miller, Patrick J O

    2015-05-21

    The killer whale is one of the few animal species with vocal dialects that arise from socially learned group-specific call repertoires. We describe a new agent-based model of killer whale populations and test a set of vocal-learning rules to assess which mechanisms may lead to the formation of dialect groupings observed in the wild. We tested a null model with genetic transmission and no learning, and ten models with learning rules that differ by template source (mother or matriline), variation type (random errors or innovations) and type of call change (no divergence from kin vs. divergence from kin). The null model without vocal learning did not produce the pattern of group-specific call repertoires we observe in nature. Learning from either mother alone or the entire matriline with calls changing by random errors produced a graded distribution of the call phenotype, without the discrete call types observed in nature. Introducing occasional innovation or random error proportional to matriline variance yielded more or less discrete and stable call types. A tendency to diverge from the calls of related matrilines provided fast divergence of loose call clusters. A pattern resembling the dialect diversity observed in the wild arose only when rules were applied in combinations and similar outputs could arise from different learning rules and their combinations. Our results emphasize the lack of information on quantitative features of wild killer whale dialects and reveal a set of testable questions that can draw insights into the cultural evolution of killer whale dialects.

  16. An agent-based model of cellular dynamics and circadian variability in human endotoxemia.

    Directory of Open Access Journals (Sweden)

    Tung T Nguyen

    Full Text Available As cellular variability and circadian rhythmicity play critical roles in immune and inflammatory responses, we present in this study an agent-based model of human endotoxemia to examine the interplay between circadian controls, cellular variability and stochastic dynamics of inflammatory cytokines. The model is qualitatively validated by its ability to reproduce circadian dynamics of inflammatory mediators and critical inflammatory responses after endotoxin administration in vivo. Novel computational concepts are proposed to characterize the cellular variability and synchronization of inflammatory cytokines in a population of heterogeneous leukocytes. Our results suggest that there is a decrease in cell-to-cell variability of inflammatory cytokines while their synchronization is increased after endotoxin challenge. Model parameters that are responsible for IκB production stimulated by NFκB activation and for the production of anti-inflammatory cytokines have large impacts on system behaviors. Additionally, examining time-dependent systemic responses revealed that the system is least vulnerable to endotoxin in the early morning and most vulnerable around midnight. Although much remains to be explored, proposed computational concepts and the model we have pioneered will provide important insights for future investigations and extensions, especially for single-cell studies to discover how cellular variability contributes to clinical implications.

  17. Comparing administered and market-based water allocation systems using an agent-based modeling approach

    Science.gov (United States)

    Zhao, J.; Cai, X.; Wang, Z.

    2009-12-01

    It also has been well recognized that market-based systems can have significant advantages over administered systems for water allocation. However there are not many successful water markets around the world yet and administered systems exist commonly in water allocation management practice. This paradox has been under discussion for decades and still calls for attention for both research and practice. This paper explores some insights for the paradox and tries to address why market systems have not been widely implemented for water allocation. Adopting the theory of agent-based system we develop a consistent analytical model to interpret both systems. First we derive some theorems based on the analytical model, with respect to the necessary conditions for economic efficiency of water allocation. Following that the agent-based model is used to illustrate the coherence and difference between administered and market-based systems. The two systems are compared from three aspects: 1) the driving forces acting on the system state, 2) system efficiency, and 3) equity. Regarding economic efficiency, penalty on the violation of water use permits (or rights) under an administered system can lead to system-wide economic efficiency, as well as being acceptable by some agents, which follows the theory of the so-call rational violation. Ideal equity will be realized if penalty equals incentive with an administered system and if transaction costs are zero with a market system. The performances of both agents and the over system are explained with an administered system and market system, respectively. The performances of agents are subject to different mechanisms of interactions between agents under the two systems. The system emergency (i.e., system benefit, equilibrium market price, etc), resulting from the performance at the agent level, reflects the different mechanism of the two systems, the “invisible hand” with the market system and administrative measures (penalty

  18. Patterns of Use of an Agent-Based Model and a System Dynamics Model: The Application of Patterns of Use and the Impacts on Learning Outcomes

    Science.gov (United States)

    Thompson, Kate; Reimann, Peter

    2010-01-01

    A classification system that was developed for the use of agent-based models was applied to strategies used by school-aged students to interrogate an agent-based model and a system dynamics model. These were compared, and relationships between learning outcomes and the strategies used were also analysed. It was found that the classification system…

  19. Simulation of Land-Use Development, Using a Risk-Regarding Agent-Based Model

    Directory of Open Access Journals (Sweden)

    F. Hosseinali

    2012-01-01

    Full Text Available The aim of this paper is to study the spatial consequences of applying different Attitude Utility Functions (AUFs, which reflect peoples’ simplified psychological frames, to investment plans in land-use decision making. For this purpose, we considered and implemented an agent-based model with new methods for searching landscapes, for selecting parcels to develop, and for allowing competitions among agents. Besides this, GIS (Geographic Information Systems as a versatile and powerful medium of analyzing and representing spatial data is used. Our model is implemented on an artificial landscape in which land is being developed by agents. The agents are assumed to be mobile developers that are equipped with several land-related objectives. In this paper, agents mimic various risk-bearing attitudes and sometimes compete for developing the same parcel. The results reveal that patterns of land-use development are different in the two cases of regarding and disregarding AUFs. Therefore, it is considered here that using the attitudes of people towards risk helps the model to better simulate the decision making of land-use developers. The different attitudes toward risk used in this study can be attributed to different categories of developers based on sets of characteristics such as income, age, or education.

  20. Coupling Agent-Based and Groundwater Modeling to Explore Demand Management Strategies for Shared Resources

    Science.gov (United States)

    Al-Amin, S.

    2015-12-01

    Municipal water demands in growing population centers in the arid southwest US are typically met through increased groundwater withdrawals. Hydro-climatic uncertainties attributed to climate change and land use conversions may also alter demands and impact the replenishment of groundwater supply. Groundwater aquifers are not necessarily confined within municipal and management boundaries, and multiple diverse agencies may manage a shared resource in a decentralized approach, based on individual concerns and resources. The interactions among water managers, consumers, and the environment influence the performance of local management strategies and regional groundwater resources. This research couples an agent-based modeling (ABM) framework and a groundwater model to analyze the effects of different management approaches on shared groundwater resources. The ABM captures the dynamic interactions between household-level consumers and policy makers to simulate water demands under climate change and population growth uncertainties. The groundwater model is used to analyze the relative effects of management approaches on reducing demands and replenishing groundwater resources. The framework is applied for municipalities located in the Verde River Basin, Arizona that withdraw groundwater from the Verde Formation-Basin Fill-Carbonate aquifer system. Insights gained through this simulation study can be used to guide groundwater policy-making under changing hydro-climatic scenarios for a long-term planning horizon.

  1. Agent-based model with multi-level herding for complex financial systems

    Science.gov (United States)

    Chen, Jun-Jie; Tan, Lei; Zheng, Bo

    2015-02-01

    In complex financial systems, the sector structure and volatility clustering are respectively important features of the spatial and temporal correlations. However, the microscopic generation mechanism of the sector structure is not yet understood. Especially, how to produce these two features in one model remains challenging. We introduce a novel interaction mechanism, i.e., the multi-level herding, in constructing an agent-based model to investigate the sector structure combined with volatility clustering. According to the previous market performance, agents trade in groups, and their herding behavior comprises the herding at stock, sector and market levels. Further, we propose methods to determine the key model parameters from historical market data, rather than from statistical fitting of the results. From the simulation, we obtain the sector structure and volatility clustering, as well as the eigenvalue distribution of the cross-correlation matrix, for the New York and Hong Kong stock exchanges. These properties are in agreement with the empirical ones. Our results quantitatively reveal that the multi-level herding is the microscopic generation mechanism of the sector structure, and provide new insight into the spatio-temporal interactions in financial systems at the microscopic level.

  2. Buying on margin, selling short in an agent-based market model

    Science.gov (United States)

    Zhang, Ting; Li, Honggang

    2013-09-01

    Credit trading, or leverage trading, which includes buying on margin and selling short, plays an important role in financial markets, where agents tend to increase their leverages for increased profits. This paper presents an agent-based asset market model to study the effect of the permissive leverage level on traders’ wealth and overall market indicators. In this model, heterogeneous agents can assume fundamental value-converging expectations or trend-persistence expectations, and their effective demands of assets depend both on demand willingness and wealth constraints, where leverage can relieve the wealth constraints to some extent. The asset market price is determined by a market maker, who watches the market excess demand, and is influenced by noise factors. By simulations, we examine market results for different leverage ratios. At the individual level, we focus on how the leverage ratio influences agents’ wealth accumulation. At the market level, we focus on how the leverage ratio influences changes in the asset price, volatility, and trading volume. Qualitatively, our model provides some meaningful results supported by empirical facts. More importantly, we find a continuous phase transition as we increase the leverage threshold, which may provide a further prospective of credit trading.

  3. Modelling and simulation of electrical energy systems through a complex systems approach using agent-based models

    Energy Technology Data Exchange (ETDEWEB)

    Kremers, Enrique

    2013-10-01

    Complexity science aims to better understand the processes of both natural and man-made systems which are composed of many interacting entities at different scales. A disaggregated approach is proposed for simulating electricity systems, by using agent-based models coupled to continuous ones. The approach can help in acquiring a better understanding of the operation of the system itself, e.g. on emergent phenomena or scale effects; as well as in the improvement and design of future smart grids.

  4. AJAN TABANLI MODELLEME VE HESAPLAMALI İKTİSAT - AGENT-BASED MODELLING AND COMPUTATIONAL ECONOMICS

    Directory of Open Access Journals (Sweden)

    Emrah KELEŞ

    2014-07-01

    Full Text Available ÖzetRasyonellik ve homojenlik varsayımları ile iktisadi ajanlar arasındaki etkileşimi göz ardı eden temsiliajan yaklaşımı, dinamik stokastik genel denge modellerine dayanan yerleşik iktisada duyulan güveninazalmasına yol açmıştır. 1990’ların sonlarından itibaren ajan tabanlı hesaplamalı yaklaşım finansal iktisat,endüstriyel organizasyon, makro iktisat, politik iktisat ve iktiadi ağ oluşumu başta olmak üzere sosyalbilimlerde yaygınlaşmaya başlamıştır. Son olarak 2008 küresel finansal kriz yerleşik, iktisadın dahayüksek sesle tartışılmasına ve ajan tabanlı yaklaşımın daha çok benimsenmesine neden olmuştur. Bu yeniyaklaşım araştırmacılara pasif haldeki fiziksel varlıklardan durumları, inanışları ve davranış kuralları olanaktif karar alıcılara kadar çeşitli ajanların bulunduğu yapay bir dünya kurmalarına imkân vermektedir.Bu yapay dünyalarda ajanların birbirleriyle ya da çevreleriyle etkileşimi onların adaptif (uyarlanabilirolmasına ve kompleks adaptif bir sistem meydana getirmelerine izin vermektedir. Bu çalışmada, ajantabanlı yaklaşımın temel unsurlarının incelenmesi ve DSGE modellerine göre üstünlüklerinin gösterilmesiamaçlanmıştır.AbstractAssumptions of rationality and homogeneity, and framework of representative agent that rule out interactionsbetween agents have led to a decline in confidence to mainstream economics based on dynamicstochastic equilibrium models. Starting from late 1990s, agent-based computational approach has becomeincreasingly popular in social sciences, especially in financial economics, industrial organization, macroeconomics,political economy, and economic network formation. Finally, 2008 global financial crisis hascaused mainstream to be argued loudly and agent-based approach to be adopted more. This new approachenables researchers to construct artificial worlds where various agents ranging from passive entities to active

  5. An agent-based model to study market penetration of plug-in hybrid electric vehicles

    International Nuclear Information System (INIS)

    A spatially explicit agent-based vehicle consumer choice model is developed to explore sensitivities and nonlinear interactions between various potential influences on plug-in hybrid vehicle (PHEV) market penetration. The model accounts for spatial and social effects (including threshold effects, homophily, and conformity) and media influences. Preliminary simulations demonstrate how such a model could be used to identify nonlinear interactions among potential leverage points, inform policies affecting PHEV market penetration, and help identify future data collection necessary to more accurately model the system. We examine sensitivity of the model to gasoline prices, to accuracy in estimation of fuel costs, to agent willingness to adopt the PHEV technology, to PHEV purchase price and rebates, to PHEV battery range, and to heuristic values related to gasoline usage. Our simulations indicate that PHEV market penetration could be enhanced significantly by providing consumers with ready estimates of expected lifetime fuel costs associated with different vehicles (e.g., on vehicle stickers), and that increases in gasoline prices could nonlinearly magnify the impact on fleet efficiency. We also infer that a potential synergy from a gasoline tax with proceeds is used to fund research into longer-range lower-cost PHEV batteries. - Highlights: → We model consumer agents to study potential market penetration of PHEVs. → The model accounts for spatial, social, and media effects. → We identify interactions among potential leverage points that could inform policy. → Consumer access to expected lifetime fuel costs may enhance PHEV market penetration. → Increasing PHEV battery range has synergistic effects on fleet efficiency.

  6. Provider dismissal policies and clustering of vaccine-hesitant families: an agent-based modeling approach.

    Science.gov (United States)

    Buttenheim, Alison M; Cherng, Sarah T; Asch, David A

    2013-08-01

    Many pediatric practices have adopted vaccine policies that require parents who refuse to vaccinate according to the ACIP schedule to find another health care provider. Such policies may inadvertently cluster unvaccinated patients into practices that tolerate non vaccination or alternative schedules, turning them into risky pockets of low herd immunity. The objective of this study was to assess the effect of provider zero-tolerance vaccination policies on the clustering of intentionally unvaccinated children. We developed an agent-based model of parental vaccine hesitancy, provider non-vaccination tolerance, and selection of patients into pediatric practices. We ran 84 experiments across a range of parental hesitancy and provider tolerance scenarios. When the model is initialized, all providers accommodate refusals and intentionally unvaccinated children are evenly distributed across providers. As provider tolerance decreases, hesitant children become more clustered in a smaller number of practices and eventually are not able to find a practice that will accept them. Each of these effects becomes more pronounced as the level of hesitancy in the population rises. Heterogeneity in practice tolerance to vaccine-hesitant parents has the unintended result of concentrating susceptible individuals within a small number of tolerant practices, while providing little if any compensatory protection to adherent individuals. These externalities suggest an agenda for stricter policy regulation of individual practice decisions.

  7. Conceptual Agent-Based Model for Optimal Power Utilization in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Olumide S. Adewale

    2016-06-01

    Full Text Available Wireless Sensor Networks (WSNs are densely and largely deployed in a variety of environments to sense real-world events. Many approaches have been proposed for collecting sensory data in any wireless sensor networks in a flexible, reliable, and efficient manner. In this study, we design an efficient mobile agent-based model for data gathering in wireless sensor networks to achieve energy and timely collection of sensory information in the target scene. The current focus in wireless sensor networks is placed on energy optimization during data gathering, processing and transmission. Mobile Agents (MAs as a piece of a program have attracted growing research interest that travels the network from node to node to compute the local data to get useful information globally. Mobile agent’s features such as autonomy, social ability, learning, and more significantly, mobility makes it a chosen technology for information processing in wireless sensor networks and other resource constrained computing environments. The nodes of the sensors are modelled and represented by the states of a Markov chain. The nodes are further grouped into clusters to save the energy of the nodes farther away from the base station.

  8. The Influence of Seasonal Forecast Accuracy on Farmer Behavior: An Agent-Based Modeling Approach

    Science.gov (United States)

    Jacobi, J. H.; Nay, J.; Gilligan, J. M.

    2013-12-01

    Seasonal climates dictate the livelihoods of farmers in developing countries. While farmers in developed countries often have seasonal forecasts on which to base their cropping decisions, developing world farmers usually make plans for the season without such information. Climate change increases the seasonal uncertainty, making things more difficult for farmers. Providing seasonal forecasts to these farmers is seen as a way to help buffer these typically marginal groups from the effects of climate change, though how to do so and the efficacy of such an effort is still uncertain. In Sri Lanka, an effort is underway to provide such forecasts to farmers. The accuracy of these forecasts is likely to have large impacts on how farmers accept and respond to the information they receive. We present an agent-based model to explore how the accuracy of seasonal rainfall forecasts affects the growing decisions and behavior of farmers in Sri Lanka. Using a decision function based on prospect theory, this model simulates farmers' behavior in the face of a wet, dry, or normal forecast. Farmers can either choose to grow paddy rice or plant a cash crop. Prospect theory is used to evaluate outcomes of the growing season; the farmer's memory of the level of success under a certain set of conditions affects next season's decision. Results from this study have implications for policy makers and seasonal forecasters.

  9. An Exploratory Study of the Butterfly Effect Using Agent-Based Modeling

    Science.gov (United States)

    Khasawneh, Mahmoud T.; Zhang, Jun; Shearer, Nevan E. N.; Rodriquez-Velasquez, Elkin; Bowling, Shannon R.

    2010-01-01

    This paper provides insights about the behavior of chaotic complex systems, and the sensitive dependence of the system on the initial starting conditions. How much does a small change in the initial conditions of a complex system affect it in the long term? Do complex systems exhibit what is called the "Butterfly Effect"? This paper uses an agent-based modeling approach to address these questions. An existing model from NetLogo library was extended in order to compare chaotic complex systems with near-identical initial conditions. Results show that small changes in initial starting conditions can have a huge impact on the behavior of chaotic complex systems. The term the "butterfly effect" is attributed to the work of Edward Lorenz [1]. It is used to describe the sensitive dependence of the behavior of chaotic complex systems on the initial conditions of these systems. The metaphor refers to the notion that a butterfly flapping its wings somewhere may cause extreme changes in the ecological system's behavior in the future, such as a hurricane.

  10. Retail Location Choice with Complementary Goods: An Agent-Based Model

    Science.gov (United States)

    Huang, Arthur; Levinson, David

    This paper models the emergence of retail clusters on a supply chain network comprised of suppliers, retailers, and consumers. Firstly, an agent-based model is proposed to investigate retail location distribution in a market of two complementary goods. The methodology controls for supplier locales and unit sales prices of retailers and suppliers, and a consumer’s willingness to patronize a retailer depends on the total travel distance of buying both goods. On a circle comprised of discrete locations, retailers play a non-cooperative game of location choice to maximize individual profits. Our findings suggest that the probability distribution of the number of clusters in equilibrium follows power law and that hierarchical distribution patterns are much more likely to occur than the spread-out ones. In addition, retailers of complementary goods tend to co-locate at supplier locales. Sensitivity tests on the number of retailers are also performed. Secondly, based on the County Business Patterns (CBP) data of Minneapolis-St. Paul from US Census 2000 database, we find that the number of clothing stores and the distribution of food stores at the zip code level follows power-law distribution.

  11. Temporal asymmetries in Interbank Market: an empirically grounded Agent-Based Model

    Science.gov (United States)

    Zlatic, Vinko; Popovic, Marko; Abraham, Hrvoje; Caldarelli, Guido; Iori, Giulia

    2014-03-01

    We analyse the changes in the topology of the structure of the E-mid interbank market in the period from September 1st 1999 to September 1st 2009. We uncover a type of temporal irreversibility in the growth of the largest component of the interbank trading network, which is not common to any of the usual network growth models. Such asymmetry, which is also detected on the growth of the clustering and reciprocity coefficient, reveals that the trading mechanism is driven by different dynamics at the beginning and at the end of the day. We are able to recover the complexity of the system by means of a simple Agent Based Model in which the probability of matching between counter parties depends on a time varying vertex fitness (or attractiveness) describing banks liquidity needs. We show that temporal irreversibility is associated with heterogeneity in the banking system and emerges when the distribution of liquidity shocks across banks is broad. We acknowledge support from FET project FOC-II.

  12. Emergent patterns of social organization in captive Cercocebus torquatus: Testing the GrooFiWorld agent-based model

    Indian Academy of Sciences (India)

    R Dolado; F S Beltran

    2012-09-01

    We empirically applied the GrooFiWorld agent-based model (Puga-González et al. 2009) in a group of captive red-capped mangabeys (Cercocebus torquatus). We analysed several measurements related to aggression and affiliative patterns. The group adopted a combination of despotic and egalitarian behaviours resulting from the behavioural flexibility observed in the Cercopithecinae subfamily. Our study also demonstrates that the GrooFiWorld agent-based model can be extended to other members of the Cercopithecinae subfamily generating parsimonious hypotheses related to the social organization.

  13. An artificial intelligence approach for modeling molecular self-assembly: agent-based simulations of rigid molecules.

    Science.gov (United States)

    Fortuna, Sara; Troisi, Alessandro

    2009-07-23

    Agent-based simulations are rule-based models traditionally used for the simulations of complex systems. In this paper, an algorithm based on the concept of agent-based simulations is developed to predict the lowest energy packing of a set of identical rigid molecules. The agents are identified with rigid portions of the system under investigation, and they evolve following a set of rules designed to drive the system toward the lowest energy minimum. The algorithm is compared with a conventional Metropolis Monte Carlo algorithm, and it is applied on a large set of representative models of molecules. For all the systems studied, the agent-based method consistently finds a significantly lower energy minima than the Monte Carlo algorithm because the system evolution includes elements of adaptation (new configurations induce new types of moves) and learning (past successful choices are repeated).

  14. An Agent-based Strategy for Deploying Analysis Models into Specification and Design for Distributed APS Systems

    CERN Document Server

    de Santa-Eulalia, Luis Antonio; Frayret, Jean-Marc

    2011-01-01

    Despite the extensive use of the agent technology in the Supply Chain Management field, its integration with Advanced Planning and Scheduling (APS) tools still represents a promising field with several open research questions. Specifically, the literature falls short in providing an integrated framework to analyze, specify, design and implement simulation experiments covering the whole simulation cycle. Thus, this paper proposes an agent-based strategy to convert the 'analysis' models into 'specification' and 'design' models combining two existing methodologies proposed in the literature. The first one is a recent and unique approach dedicated to the 'analysis' of agent-based APS systems. The second one is a well-established methodological framework to 'specify' and 'design' agent-based supply chain systems. The proposed conversion strategy is original and is the first one allowing simulation analysts to integrate the whole simulation development process in the domain of distributed APS.

  15. A Collective Case Study of Secondary Students' Model-Based Inquiry on Natural Selection through Programming in an Agent-Based Modeling Environment

    Science.gov (United States)

    Xiang, Lin

    2011-01-01

    This is a collective case study seeking to develop detailed descriptions of how programming an agent-based simulation influences a group of 8th grade students' model-based inquiry (MBI) by examining students' agent-based programmable modeling (ABPM) processes and the learning outcomes. The context of the present study was a biology unit on…

  16. Simulation of the Role of Government in Spatial Agent-Based Model

    Directory of Open Access Journals (Sweden)

    Viktor Ivanovich Suslov

    2016-09-01

    Full Text Available The paper describes the further development of an agent-based multiregional input-output model of the Russian economy. We consider the idea of incorporating the government into the model and analyze the results of experimental calculations for the conditional example of spatial economy. New agents are included into the model such as the federal and regional governments, pension fund and also the state enterprises producing public goods at the federal and regional levels. The government sets four types of taxes (personal and business income taxes, VAT and payroll taxes, ensures the provision of public goods and provides social, investment and interbudgetary transfers to households, firms and budgets. Social transfers consist of social assistance and unemployment benefits. The utility functions of households are expanded by the terms associated with national and regional public goods. The budget policy is designed in accordance with the maximization of isoelastic function of social welfare that formalizes the choice between the different concepts of social justice. The Gini index is used for the monitoring the inequality of income distribution. The results of experimental calculations present the convergence of the new version of the model to the state of quasi-equilibrium. The special attention is paid an optimal level of the taxation maximizing the social welfare function. Four variants of the optimal tax rates are defined: for three major taxes at a fixed proportion of rates and for each of the tax separately at zero rates of two other taxes. The further directions of modelling are identified, they allow to investigate the spatial development of the Russian economy taking into account the decision-making by private agents in responding to government policies.

  17. Agent Based Modeling of Air Carrier Behavior for Evaluation of Technology Equipage and Adoption

    Science.gov (United States)

    Horio, Brant M.; DeCicco, Anthony H.; Stouffer, Virginia L.; Hasan, Shahab; Rosenbaum, Rebecca L.; Smith, Jeremy C.

    2014-01-01

    As part of ongoing research, the National Aeronautics and Space Administration (NASA) and LMI developed a research framework to assist policymakers in identifying impacts on the U.S. air transportation system (ATS) of potential policies and technology related to the implementation of the Next Generation Air Transportation System (NextGen). This framework, called the Air Transportation System Evolutionary Simulation (ATS-EVOS), integrates multiple models into a single process flow to best simulate responses by U.S. commercial airlines and other ATS stakeholders to NextGen-related policies, and in turn, how those responses impact the ATS. Development of this framework required NASA and LMI to create an agent-based model of airline and passenger behavior. This Airline Evolutionary Simulation (AIRLINE-EVOS) models airline decisions about tactical airfare and schedule adjustments, and strategic decisions related to fleet assignments, market prices, and equipage. AIRLINE-EVOS models its own heterogeneous population of passenger agents that interact with airlines; this interaction allows the model to simulate the cycle of action-reaction as airlines compete with each other and engage passengers. We validated a baseline configuration of AIRLINE-EVOS against Airline Origin and Destination Survey (DB1B) data and subject matter expert opinion, and we verified the ATS-EVOS framework and agent behavior logic through scenario-based experiments. These experiments demonstrated AIRLINE-EVOS's capabilities in responding to an input price shock in fuel prices, and to equipage challenges in a series of analyses based on potential incentive policies for best equipped best served, optimal-wind routing, and traffic management initiative exemption concepts..

  18. An agent-based modeling approach for determining corn stover removal rate and transboundary effects.

    Science.gov (United States)

    Gan, Jianbang; Langeveld, J W A; Smith, C T

    2014-02-01

    Bioenergy production involves different agents with potentially different objectives, and an agent's decision often has transboundary impacts on other agents along the bioenergy value chain. Understanding and estimating the transboundary impacts is essential to portraying the interactions among the different agents and in the search for the optimal configuration of the bioenergy value chain. We develop an agent-based model to mimic the decision making by feedstock producers and feedstock-to-biofuel conversion plant operators and propose multipliers (i.e., ratios of economic values accruing to different segments and associated agents in the value chain) for assessing the transboundary impacts. Our approach is generic and thus applicable to a variety of bioenergy production systems at different sites and geographic scales. We apply it to the case of producing ethanol using corn stover in Iowa, USA. The results from the case study indicate that stover removal rate is site specific and varies considerably with soil type, as well as other factors, such as stover price and harvesting cost. In addition, ethanol production using corn stover in the study region would have strong positive ripple effects, with the values of multipliers varying with greenhouse gas price and national energy security premium. The relatively high multiplier values suggest that a large portion of the value associated with corn stover ethanol production would accrue to the downstream end of the value chain instead of stover producers.

  19. Evaluating Infection Prevention Strategies in Out-Patient Dialysis Units Using Agent-Based Modeling

    Science.gov (United States)

    Wares, Joanna R.; Lawson, Barry; Shemin, Douglas; D’Agata, Erika M. C.

    2016-01-01

    Patients receiving chronic hemodialysis (CHD) are among the most vulnerable to infections caused by multidrug-resistant organisms (MDRO), which are associated with high rates of morbidity and mortality. Current guidelines to reduce transmission of MDRO in the out-patient dialysis unit are targeted at patients considered to be high-risk for transmitting these organisms: those with infected skin wounds not contained by a dressing, or those with fecal incontinence or uncontrolled diarrhea. Here, we hypothesize that targeting patients receiving antimicrobial treatment would more effectively reduce transmission and acquisition of MDRO. We also hypothesize that environmental contamination plays a role in the dissemination of MDRO in the dialysis unit. To address our hypotheses, we built an agent-based model to simulate different treatment strategies in a dialysis unit. Our results suggest that reducing antimicrobial treatment, either by reducing the number of patients receiving treatment or by reducing the duration of the treatment, markedly reduces overall colonization rates and also the levels of environmental contamination in the dialysis unit. Our results also suggest that improving the environmental decontamination efficacy between patient dialysis treatments is an effective method for reducing colonization and contamination rates. These findings have important implications for the development and implementation of future infection prevention strategies. PMID:27195984

  20. A MARKET-ORIENTED AGENTS-BASED MODEL FOR INFORMATION RETRIEVAL

    Directory of Open Access Journals (Sweden)

    Djamel Eddine Menacer

    2014-03-01

    Full Text Available Information Retrieval in the World Wide Web (Web IR is essential for a number of activities and it is an active domain of research and devel-opment. The main challenges concern the rele-vance of the results provided to users' queries and the performance regarding respond-time. On the other hand, agent-based market systems prove to be efficient for implementing e-commerce or B2B applications on the internet, thanks to inherent properties such as prominency of interactions, scalability, flexibility, interoper-ability, etc. Although the use of agents in other application domains is not yet widespread, the integration of mobile agents into market mecha-nisms bring clear and efficient solutions to Qual-ity of Service issues encountered in most distrib-uted applications and notably in Web IR systems. Mobility allows defining the seller – buyer model of interaction, where agents act on behalf of final users or devices providing re-sources, while the generic Market Place archi-tecture provides an organizational setting for the matching of demands and offers. The paper shows how this framework applies to Web IR and provides experimental validation results from a Jade implementation.

  1. Spatiotemporal analysis of an agent-based model of a colony of keratinocytes: a first approach for the development of validation methods

    OpenAIRE

    Pichardo-Almarza, C.; Smallwood, R.; Billings, S. A.

    2007-01-01

    Agent-based models are widely used for the simulation of systems from several domains (biology, economics, meteorology, etc). In biology agent-based models are very useful for predicting the social behaviour of systems; in particular they seem well adapted to model the behaviour of a cell population. In this paper an agent-based model, developed to study normal human keratinocytes (tissue cells), will be investigated. This kind of model exhibits probabilistic behavi...

  2. Multi-Equilibria Regulation Agent-Based Model of Opinion Dynamics in Social Networks

    Directory of Open Access Journals (Sweden)

    Andreas Koulouris

    2013-01-01

    Full Text Available This article investigates the Multiple Equilibria Regulation (MER model, i.e., an agent-based simulation model, to represent opinion dynamics in social networks. It relies on a small set of micro-prerequisites (intra-individual balance and confidence bound, leading to emergence of (nonstationary macro-outcomes. These outcomes may refer to consensus, polarization or fragmentation of opinions about taxation (e.g., congestion pricing or other policy measures, according to the way communication is structured. In contrast with other models of opinion dynamics, it allows for the impact of both the regulation of intra-personal discrepancy and the interpersonal variability of opinions on social learning and network dynamics. Several simulation experiments are presented to demonstrate, through the MER model, the role of different network structures (complete, star, cellular automata, small-world and random graphs on opinion formation dynamics and the overall evolution of the system. The findings can help to identify specific topological characteristics, such as density, number of neighbourhoods and critical nodes-agents, that affect the stability and system dynamics. This knowledge can be used to better organize the information diffusion and learning in the community, enhance the predictability of outcomes and manage possible conflicts. It is shown that a small-world organization, which depicts more realistic aspects of real-life and virtual social systems, provides increased predictability and stability towards a less fragmented and more manageable grouping of opinions, compared to random networks. Such macro-level organizations may be enhanced with use of web-based technologies to increase the density of communication and public acceptability of policy measures.

  3. An agent-based model of dialect evolution in killer whales.

    Science.gov (United States)

    Filatova, Olga A; Miller, Patrick J O

    2015-05-21

    The killer whale is one of the few animal species with vocal dialects that arise from socially learned group-specific call repertoires. We describe a new agent-based model of killer whale populations and test a set of vocal-learning rules to assess which mechanisms may lead to the formation of dialect groupings observed in the wild. We tested a null model with genetic transmission and no learning, and ten models with learning rules that differ by template source (mother or matriline), variation type (random errors or innovations) and type of call change (no divergence from kin vs. divergence from kin). The null model without vocal learning did not produce the pattern of group-specific call repertoires we observe in nature. Learning from either mother alone or the entire matriline with calls changing by random errors produced a graded distribution of the call phenotype, without the discrete call types observed in nature. Introducing occasional innovation or random error proportional to matriline variance yielded more or less discrete and stable call types. A tendency to diverge from the calls of related matrilines provided fast divergence of loose call clusters. A pattern resembling the dialect diversity observed in the wild arose only when rules were applied in combinations and similar outputs could arise from different learning rules and their combinations. Our results emphasize the lack of information on quantitative features of wild killer whale dialects and reveal a set of testable questions that can draw insights into the cultural evolution of killer whale dialects. PMID:25817037

  4. A multiscale agent-based in silico model of liver fibrosis progression

    Directory of Open Access Journals (Sweden)

    Joyeeta eDutta-Moscato

    2014-05-01

    Full Text Available Chronic hepatic inflammation involves a complex interplay of inflammatory and mechanical influences, ultimately manifesting in a characteristic histopathology of liver fibrosis. We created an agent-based model (ABM of liver tissue in order to computationally examine the consequence of liver inflammation. Our Liver Fibrosis ABM (LFABM is comprised of literature-derived rules describing molecular and histopathologic aspects of inflammation and fibrosis in a section of chemically injured liver. Hepatocytes are modeled as agents within hexagonal lobules. Injury triggers an inflammatory reaction, which leads to activation of local Kupffer cells and recruitment of monocytes from circulation. Portal fibroblasts and hepatic stellate cells are activated locally by the products of inflammation. The various agents in the simulation are regulated by above-threshold concentrations of pro- and anti-inflammatory cytokines and damage-associated molecular pattern (DAMP molecules. The simulation progresses from chronic inflammation to collagen deposition, exhibiting periportal fibrosis followed by bridging fibrosis, and culminating in disruption of the regular lobular structure. The ABM exhibited key histopathologic features observed in liver sections from rats treated with carbon tetrachloride (CCl4. An in silico tension test for the hepatic lobules predicted an overall increase in tissue stiffness, in line with clinical elastography literature and published studies in CCl4-treated rats. Therapy simulations suggested differential anti-fibrotic effects of neutralizing TNF-a vs. enhancing M2 Kupffer cells. We conclude that a computational model of liver inflammation on a structural skeleton of physical forces can recapitulate key histopathologic and macroscopic properties of CCl4-injured liver. This multiscale approach linking molecular and chemomechanical stimuli enables a model that could be used to gain translationally relevant insights into live fibrosis.

  5. A risk assessment example for soil invertebrates using spatially explicit agent-based models.

    Science.gov (United States)

    Reed, Melissa; Alvarez, Tania; Chelinho, Sónia; Forbes, Valery; Johnston, Alice; Meli, Mattia; Voss, Frank; Pastorok, Rob

    2016-01-01

    Current risk assessment methods for measuring the toxicity of plant protection products (PPPs) on soil invertebrates use standardized laboratory conditions to determine acute effects on mortality and sublethal effects on reproduction. If an unacceptable risk is identified at the lower tier, population-level effects are assessed using semifield and field trials at a higher tier because modeling methods for extrapolating available lower-tier information to population effects have not yet been implemented. Field trials are expensive, time consuming, and cannot be applied to variable landscape scenarios. Mechanistic modeling of the toxicological effects of PPPs on individuals and their responses combined with simulation of population-level response shows great potential in fulfilling such a need, aiding ecologically informed extrapolation. Here, we introduce and demonstrate the potential of 2 population models for ubiquitous soil invertebrates (collembolans and earthworms) as refinement options in current risk assessment. Both are spatially explicit agent-based models (ABMs), incorporating individual and landscape variability. The models were used to provide refined risk assessments for different application scenarios of a hypothetical pesticide applied to potato crops (full-field spray onto the soil surface [termed "overall"], in-furrow, and soil-incorporated pesticide applications). In the refined risk assessment, the population models suggest that soil invertebrate populations would likely recover within 1 year after pesticide application, regardless of application method. The population modeling for both soil organisms also illustrated that a lower predicted average environmental concentration in soil (PECsoil) could potentially lead to greater effects at the population level, depending on the spatial heterogeneity of the pesticide and the behavior of the soil organisms. Population-level effects of spatial-temporal variations in exposure were elucidated in the

  6. An integrated framework of agent-based modelling and robust optimization for microgrid energy management

    International Nuclear Information System (INIS)

    Highlights: • Microgrid composed of a train station, wind power plant and district is investigated. • Each player is modeled as an individual agent aiming at a particular goal. • Prediction Intervals quantify the uncertain operational and environmental parameters. • Optimal goal-directed actions planning is achieved with robust optimization. • Optimization framework improves system reliability and decreases power imbalances. - Abstract: A microgrid energy management framework for the optimization of individual objectives of microgrid stakeholders is proposed. The framework is exemplified by way of a microgrid that is connected to an external grid via a transformer and includes the following players: a middle-size train station with integrated photovoltaic power production system, a small energy production plant composed of urban wind turbines, and a surrounding district including residences and small businesses. The system is described by Agent-Based Modelling (ABM), in which each player is modelled as an individual agent aiming at a particular goal, (i) decreasing its expenses for power purchase or (ii) increasing its revenues from power selling. The context in which the agents operate is uncertain due to the stochasticity of operational and environmental parameters, and the technical failures of the renewable power generators. The uncertain operational and environmental parameters of the microgrid are quantified in terms of Prediction Intervals (PIs) by a Non-dominated Sorting Genetic Algorithm (NSGA-II) – trained Neural Network (NN). Under these uncertainties, each agent is seeking for optimal goal-directed actions planning by Robust Optimization (RO). The developed framework is shown to lead to an increase in system performance, evaluated in terms of typical reliability (adequacy) indicators for energy systems, such as Loss of Load Expectation (LOLE) and Loss of Expected Energy (LOEE), in comparison with optimal planning based on expected values of

  7. Agent-based modeling of oxygen-responsive transcription factors in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Hao Bai

    2014-04-01

    Full Text Available In the presence of oxygen (O2 the model bacterium Escherichia coli is able to conserve energy by aerobic respiration. Two major terminal oxidases are involved in this process - Cyo has a relatively low affinity for O2 but is able to pump protons and hence is energetically efficient; Cyd has a high affinity for O2 but does not pump protons. When E. coli encounters environments with different O2 availabilities, the expression of the genes encoding the alternative terminal oxidases, the cydAB and cyoABCDE operons, are regulated by two O2-responsive transcription factors, ArcA (an indirect O2 sensor and FNR (a direct O2 sensor. It has been suggested that O2-consumption by the terminal oxidases located at the cytoplasmic membrane significantly affects the activities of ArcA and FNR in the bacterial nucleoid. In this study, an agent-based modeling approach has been taken to spatially simulate the uptake and consumption of O2 by E. coli and the consequent modulation of ArcA and FNR activities based on experimental data obtained from highly controlled chemostat cultures. The molecules of O2, transcription factors and terminal oxidases are treated as individual agents and their behaviors and interactions are imitated in a simulated 3-D E. coli cell. The model implies that there are two barriers that dampen the response of FNR to O2, i.e. consumption of O2 at the membrane by the terminal oxidases and reaction of O2 with cytoplasmic FNR. Analysis of FNR variants suggested that the monomer-dimer transition is the key step in FNR-mediated repression of gene expression.

  8. A hybrid agent-based model of the developing mammary terminal end bud.

    Science.gov (United States)

    Butner, Joseph D; Chuang, Yao-Li; Simbawa, Eman; Al-Fhaid, A S; Mahmoud, S R; Cristini, Vittorio; Wang, Zhihui

    2016-10-21

    Mammary gland ductal elongation is spearheaded by terminal end buds (TEBs), where populations of highly proliferative cells are maintained throughout post-pubertal organogenesis in virgin mice until the mammary fat pad is filled by a mature ductal tree. We have developed a hybrid multiscale agent-based model to study how cellular differentiation pathways, cellular proliferation capacity, and endocrine and paracrine signaling play a role during development of the mammary gland. A simplified cellular phenotypic hierarchy that includes stem, progenitor, and fully differentiated cells within the TEB was implemented. Model analysis finds that mammary gland development was highly sensitive to proliferation events within the TEB, with progenitors likely undergoing 2-3 proliferation cycles before transitioning to a non-proliferative phenotype, and this result is in agreement with our previous experimental work. Endocrine and paracrine signaling were found to provide reliable ductal elongation rate regulation, while variations in the probability a new daughter cell will be of a proliferative phenotype were seen to have minimal effects on ductal elongation rates. Moreover, the distribution of cellular phenotypes within the TEB was highly heterogeneous, demonstrating significant allowable plasticity in possible phenotypic distributions while maintaining biologically relevant growth behavior. Finally, simulation results indicate ductal elongation rates due to cellular proliferation within the TEB may have a greater sensitivity to upstream endocrine signaling than endothelial to stromal paracrine signaling within the TEB. This model provides a useful tool to gain quantitative insights into cellular population dynamics and the effects of endocrine and paracrine signaling within the pubertal terminal end bud. PMID:27475843

  9. An operational epidemiological model for calibrating agent-based simulations of pandemic influenza outbreaks.

    Science.gov (United States)

    Prieto, D; Das, T K

    2016-03-01

    Uncertainty of pandemic influenza viruses continue to cause major preparedness challenges for public health policymakers. Decisions to mitigate influenza outbreaks often involve tradeoff between the social costs of interventions (e.g., school closure) and the cost of uncontrolled spread of the virus. To achieve a balance, policymakers must assess the impact of mitigation strategies once an outbreak begins and the virus characteristics are known. Agent-based (AB) simulation is a useful tool for building highly granular disease spread models incorporating the epidemiological features of the virus as well as the demographic and social behavioral attributes of tens of millions of affected people. Such disease spread models provide excellent basis on which various mitigation strategies can be tested, before they are adopted and implemented by the policymakers. However, to serve as a testbed for the mitigation strategies, the AB simulation models must be operational. A critical requirement for operational AB models is that they are amenable for quick and simple calibration. The calibration process works as follows: the AB model accepts information available from the field and uses those to update its parameters such that some of its outputs in turn replicate the field data. In this paper, we present our epidemiological model based calibration methodology that has a low computational complexity and is easy to interpret. Our model accepts a field estimate of the basic reproduction number, and then uses it to update (calibrate) the infection probabilities in a way that its effect combined with the effects of the given virus epidemiology, demographics, and social behavior results in an infection pattern yielding a similar value of the basic reproduction number. We evaluate the accuracy of the calibration methodology by applying it for an AB simulation model mimicking a regional outbreak in the US. The calibrated model is shown to yield infection patterns closely replicating

  10. Integration of Life Cycle Assessment Into Agent-Based Modeling: Toward Informed Decisions on Evolving Infrastructure Systems

    NARCIS (Netherlands)

    Davis, C.B.; Nikolić, I.; Dijkema, G.P.J.

    2009-01-01

    A method is presented that allows for a life cycle assessment (LCA) to provide environmental information on an energy infrastructure system while it evolves. Energy conversion facilities are represented in an agent-based model (ABM) as distinct instances of technologies with owners capable of making

  11. Multi-agent Based Hierarchy Simulation Models of Carrier-based Aircraft Catapult Launch

    Institute of Scientific and Technical Information of China (English)

    Wang Weijun; Qu Xiangju; Guo Linliang

    2008-01-01

    With the aid of multi-agent based modeling approach to complex systems,the hierarchy simulation models of carrier-based aircraft catapult launch are developed.Ocean,carrier,aircraft,and atmosphere are treated as aggregation agents,the detailed components like catapult,landing gears,and disturbances are considered as meta-agents,which belong to their aggregation agent.Thus,the model with two layers is formed i.e.the aggregation agent layer and the meta-agent layer.The information communication among all agents is described.The meta-agents within one aggregation agent communicate with each other directly by information sharing,but the meta-agents,which belong to different aggregation agents exchange their information through the aggregation layer fast,and then perceive it from the sharing environment,that is the aggregation agent.Thus,not only the hierarchy model is built,but also the environment perceived by each agent is specified.Meanwhile,the problem of balancing the independency of agent and the resource consumption brought by real-time communication within multi-agent system (MAS) is resolved.Each agent involved in carrier-based aircraft catapult launch is depicted,with considering the interaction within disturbed atmospheric environment and multiple motion bodies including carrier,aircraft,and landing gears.The models of reactive agents among them are derived based on tensors,and the perceived messages and inner frameworks of each agent are characterized.Finally,some results of a simulation instance are given.The simulation and modeling of dynamic system based on multi-agent system is of benefit to express physical concepts and logical hierarchy clearly and precisely.The system model can easily draw in kinds of other agents to achieve a precise simulation of more complex system.This modeling technique makes the complex integral dynamic equations of multibodies decompose into parallel operations of single agent,and it is convenient to expand,maintain,and reuse

  12. Diffusion of a Sustainable Farming Technique in Sri Lanka: An Agent-Based Modeling Approach

    Science.gov (United States)

    Jacobi, J. H.; Gilligan, J. M.; Carrico, A. R.; Truelove, H. B.; Hornberger, G.

    2012-12-01

    We live in a changing world - anthropogenic climate change is disrupting historic climate patterns and social structures are shifting as large scale population growth and massive migrations place unprecedented strain on natural and social resources. Agriculture in many countries is affected by these changes in the social and natural environments. In Sri Lanka, rice farmers in the Mahaweli River watershed have seen increases in temperature and decreases in precipitation. In addition, a government led resettlement project has altered the demographics and social practices in villages throughout the watershed. These changes have the potential to impact rice yields in a country where self-sufficiency in rice production is a point of national pride. Studies of the climate can elucidate physical effects on rice production, while research on social behaviors can illuminate the influence of community dynamics on agricultural practices. Only an integrated approach, however, can capture the combined and interactive impacts of these global changes on Sri Lankan agricultural. As part of an interdisciplinary team, we present an agent-based modeling (ABM) approach to studying the effects of physical and social changes on farmers in Sri Lanka. In our research, the diffusion of a sustainable farming technique, the system of rice intensification (SRI), throughout a farming community is modeled to identify factors that either inhibit or promote the spread of a more sustainable approach to rice farming. Inputs into the ABM are both physical and social and include temperature, precipitation, the Palmer Drought Severity Index (PDSI), community trust, and social networks. Outputs from the ABM demonstrate the importance of meteorology and social structure on the diffusion of SRI throughout a farming community.

  13. The role of chromosome missegregation in cancer development: a theoretical approach using agent-based modelling.

    Directory of Open Access Journals (Sweden)

    Arturo Araujo

    Full Text Available Many cancers are aneuploid. However, the precise role that chromosomal instability plays in the development of cancer and in the response of tumours to treatment is still hotly debated. Here, to explore this question from a theoretical standpoint we have developed an agent-based model of tissue homeostasis in which to test the likely effects of whole chromosome mis-segregation during cancer development. In stochastic simulations, chromosome mis-segregation events at cell division lead to the generation of a diverse population of aneuploid clones that over time exhibit hyperplastic growth. Significantly, the course of cancer evolution depends on genetic linkage, as the structure of chromosomes lost or gained through mis-segregation events and the level of genetic instability function in tandem to determine the trajectory of cancer evolution. As a result, simulated cancers differ in their level of genetic stability and in their growth rates. We used this system to investigate the consequences of these differences in tumour heterogeneity for anti-cancer therapies based on surgery and anti-mitotic drugs that selectively target proliferating cells. As expected, simulated treatments induce a transient delay in tumour growth, and reveal a significant difference in the efficacy of different therapy regimes in treating genetically stable and unstable tumours. These data support clinical observations in which a poor prognosis is correlated with a high level of chromosome mis-segregation. However, stochastic simulations run in parallel also exhibit a wide range of behaviours, and the response of individual simulations (equivalent to single tumours to anti-cancer therapy prove extremely variable. The model therefore highlights the difficulties of predicting the outcome of a given anti-cancer treatment, even in cases in which it is possible to determine the genotype of the entire set of cells within the developing tumour.

  14. Bayesian networks and agent-based modeling approach for urban land-use and population density change: a BNAS model

    Science.gov (United States)

    Kocabas, Verda; Dragicevic, Suzana

    2013-10-01

    Land-use change models grounded in complexity theory such as agent-based models (ABMs) are increasingly being used to examine evolving urban systems. The objective of this study is to develop a spatial model that simulates land-use change under the influence of human land-use choice behavior. This is achieved by integrating the key physical and social drivers of land-use change using Bayesian networks (BNs) coupled with agent-based modeling. The BNAS model, integrated Bayesian network-based agent system, presented in this study uses geographic information systems, ABMs, BNs, and influence diagram principles to model population change on an irregular spatial structure. The model is parameterized with historical data and then used to simulate 20 years of future population and land-use change for the City of Surrey, British Columbia, Canada. The simulation results identify feasible new urban areas for development around the main transportation corridors. The obtained new development areas and the projected population trajectories with the“what-if” scenario capabilities can provide insights into urban planners for better and more informed land-use policy or decision-making processes.

  15. Application of statistical emulation to an agent-based model: assortative mating and the reversal of gender inequality in education in Belgium.

    OpenAIRE

    De Mulder, Wim; Grow, André; Molenberghs, Geert; Verbeke, Geert

    2015-01-01

    We describe the application of statistical emulation to the outcomes of an agent-based model. The agent-based model simulates the mechanisms that might have linked the reversal of gender inequality in higher education with observed changes in educational assortative mating in Belgium. Using the statistical emulator as a computationally fast approximation to the expensive agent-based model, it is feasible to use a genetic algorithm in nding the parameter values for which the correspondin...

  16. Optimizing the structure of the natural gas market using an agent-based modeling framework

    International Nuclear Information System (INIS)

    The overall research question guiding this study is as follows: what is the optimal structure of the natural gas market, considering both the degrees of affordability and supply security resulting from this structure? The sub-questions are: How can the concepts of supply security and affordability be usefully defined? (Chapter 2); What should a modeling framework for analyzing the natural gas market with regard to these concepts look like? (Chapters 3 and 4); What general conclusions can be drawn on the basis of this framework? (Chapter 5); What is the effect of liberalization on the Dutch natural gas market? (Chapter 6); What are the possible effects of current trends unfolding in the Dutch natural gas market? (Chapter 7). The framework constructed in this study implicitly contains the necessary elements for deriving a sustainability indicator too. However, to limit the scope of the study, sustainability will not be analyzed explicitly. Chapter 2 provides an introductory description of the natural gas market. Starting from a description of the natural gas value chain, the process of liberalization is described as a change in the organization of the value chain. In addition, the concepts of affordability and supply security are discussed and appropriate quantitative indicators for both objectives are identified. In Chapter 3, a survey of existing gas market models is performed. On the basis of this survey, a classification system for natural gas market models is developed. Furthermore, the characteristics of a modeling framework fit for the purpose of this study are derived. In Chapter 4, a general, quantitative framework for natural gas market modeling is developed on the basis of agent-based computational economics. The model's structure, its dynamics, output and data requirements are described. Furthermore, the properties of each agent are explored, and the possibilities for model verification and validation are outlined. Chapter 5 provides a number of

  17. Toward an Agent-Based Model of Socially Optimal Water Rights Markets

    Science.gov (United States)

    Ehlen, M. A.

    2004-12-01

    There has been considerable interest lately in using public markets for buying and selling the rights to local water usage. Such water rights markets, if designed correctly, should be socially optimal, that is, should sell rights at prices that reflect the true value of water in the region, taking into account that water rights buyers and sellers represent a disparate group of private industry, public authorities, and private users, each having different water needs and different priority to local government. Good market design, however, is hard. As was experienced in California short-run electric power markets, a market design that on paper looks reasonable but in practice is mal-constructed can have devastating effects: firms can learn to manipulate prices by `playing' both sides of the market, and sellers can under-provide so as to create exorbitant prices which buyers have no choice but to pay. Economic theory provides several frameworks for developing a good water rights market design; for example, the structure-conduct-performance paradigm (SCPP) suggests that, among other things, the number and types of buyers and sellers (structure), and transaction clearing rules and government policies (conduct) affect in very particular ways the prices and quantities (performance) in the market. In slow-moving or static markets, SCPP has been a useful predictor of market performance; in faster markets the market dynamics that endogenously develop over time are often too complex to predict with SCPP or other existing modeling techniques. New, more sophisticated combinations of modeling and simulation are needed. Toward developing a good (i.e., socially optimal) water rights market design that can take into account the dynamics inherent in the water sector, we are developing an agent-based model of water rights markets. The model serves two purposes: first, it provides an SCPP-based framework of water rights markets that takes into account the particular structure of

  18. Using an agent-based model to analyze the dynamic communication network of the immune response

    Directory of Open Access Journals (Sweden)

    Doolittle John

    2011-01-01

    loss outcomes. Conclusions An agent-based model capturing several key aspects of complex system dynamics was used to study the emergent properties of the immune response to viral infection. Specific patterns of interactions between leukocyte agents occurring early in the response significantly improved outcome. More interactions at later stages correlated with persistent inflammation and infection. These simulation experiments highlight the importance of commonly overlooked aspects of the immune response and provide insight into these processes at a resolution level exceeding the capabilities of current laboratory technologies.

  19. Preparation and imaging study of tumor-targeting MRI contrast agent based on Fe3O4 nanoparticles

    International Nuclear Information System (INIS)

    The detection and diagnosis of early hypoxic tumor is the key for successful cancer therapy, which remains a challenge for radiologists because contrast agents could hardly reach it. Herein, a tumor-targeting MRI contrast agent was prepared by conjugating the small-molecule inhibitor of carbonic anhydrase (CA IX) that is overexpressed in hypoxic tumor, mafenide, onto the surface of Fe3O4 magnetic nanoparticles (MNPs) to improve the sensitivity of MRI for early tumor diagnosis. The tumor-targeting MNP (Fe3O4-SO2NH2) showed enhanced MRI contrasting performance both in vitro and in vivo in comparison with the non-targeting control, which made it a promising contrast agent for the detection and diagnosis of early hypoxic tumor. (author)

  20. New methods for energy market modelling : Proceedings of the First European Workshop on Energy Market Modelling using Agent-Based Computational Economics

    OpenAIRE

    Möst, D.; Fichtner, W.; Ragwitz, M.; Veit, D. [Hrsg.

    2008-01-01

    A growing number of researchers have developed agent-based models to simulate the development of liberalized energy markets. As the field of energy market modelling with agent-based computational economics is very heterogeneous, the overview in this book might help interested researchers to get a sense for the different modelling approaches and to learn about the potential of this valuable modelling approach in different fields of the energy market.

  1. Designing across ages: Multi-agent-based models and learning electricity

    Science.gov (United States)

    Sengupta, Pratim

    Electricity is regarded as one of the most challenging topics for students at all levels -- middle school -- college (Cohen, Eylon, & Ganiel, 1983; Belcher & Olbert, 2003; Eylon & Ganiel, 1990; Steinberg et al., 1985). Several researchers have suggested that naive misconceptions about electricity stem from a deep incommensurability (Slotta & Chi, 2006; Chi, 2005) or incompatibility (Chi, Slotta & Leauw, 1994; Reiner, Slotta, Chi, & Resnick, 2000) between naive and expert knowledge structures. I first present an alternative theoretical framework that adopts an emergent levels-based perspective as proposed by Wilensky & Resnick (1999). From this perspective, macro-level phenomena such as electric current and resistance, as well as behavior of linear electric circuits, can be conceived of as emergent from simple, body-syntonic interactions between electrons and ions in a circuit. I argue that adopting such a perspective enables us to reconceive commonly noted misconceptions in electricity as behavioral evidences of "slippage between levels" -- i.e., these misconceptions appear when otherwise productive knowledge elements are sometimes inappropriately activated due to certain macro-level phenomenological cues only -- and, that the same knowledge elements when activated due to phenomenological cues at both micro- and macro-levels, can engender a deeper, expert-like understanding. I will then introduce NIELS (NetLogo Investigations In Electromagnetism, Sengupta & Wilensky, 2006, 2008, 2009), a low-threshold high-ceiling (LTHC) learning environment of multi-agent-based computational models that represent phenomena such as electric current and resistance, as well as the behavior of linear electric circuits, as emergent. I also present results from implementations of NIELS in 5th, 7th and 12th grade classrooms that show the following: (a) how leveraging certain "design elements" over others in NIELS models can create new phenomenological cues, which in turn can be

  2. Proceedings First Workshop on Applications of Membrane computing, Concurrency and Agent-based modelling in POPulation biology

    CERN Document Server

    Milazzo, Paolo; 10.4204/EPTCS.33

    2010-01-01

    This volume contains the papers presented at the first International Workshop on Applications of Membrane Computing, Concurrency and Agent-based Modelling in Population Biology (AMCA-POP 2010) held in Jena, Germany on August 25th, 2010 as a satellite event of the 11th Conference on Membrane Computing (CMC11). The aim of the workshop is to investigate whether formal modelling and analysis techniques could be applied with profit to systems of interest for population biology and ecology. The considered modelling notations include membrane systems, Petri nets, agent-based notations, process calculi, automata-based notations, rewriting systems and cellular automata. Such notations enable the application of analysis techniques such as simulation, model checking, abstract interpretation and type systems to study systems of interest in disciplines such as population biology, ecosystem science, epidemiology, genetics, sustainability science, evolution and other disciplines in which population dynamics and interactions...

  3. An agent-based model to investigate the roles of attractive and repellent pheromones in ant decision making during foraging

    OpenAIRE

    Robinson, Elva J. H.; Ratnieks, Francis L. W.; Holcombe, M.

    2008-01-01

    Pharaoh's ants organise their foraging system using three types of trail pheromone. All previous foraging models based on specific ant foraging systems have assumed that only a single attractive pheromone is used. Here we present an agent-based model based on trail choice at a trail bifurcation within the foraging trail network of a Pharaoh's ant colony which includes both attractive (positive) and repellent (negative) trail pheromones. Experiments have previously shown that Pharaoh's ants us...

  4. A market-oriented agent-based model for information retrieval

    OpenAIRE

    Menacer, Djamel Eddine; Sibertin-Blanc, Christophe; Drias, Habiba

    2013-01-01

    International audience Information Retrieval in the World Wide Web (Web IR) is essential for a number of activities and it is an active domain of research and development. The main challenges concern the relevance of the results provided to users' queries and the performance regarding respond-time. On the other hand, agent-based market systems prove to be efficient for implementing e-commerce or B2B applications on the internet, thanks to inherent properties such as prominency of interacti...

  5. Exploring the polycentric city with multi-worker households: an agent-based microeconomic model

    OpenAIRE

    LEMOY, Rémi; Raux, Charles; Jensen, Pablo

    2013-01-01

    We propose an agent-based dynamics which leads an urban system to the standard equilibrium of the Alonso, Muth, Mills (AMM) framework. Starting for instance from a random initialization, agents move and bid for land, performing a kind of local search and finally leading the system to equilibrium rent, density and land use. Agreement with continuous analytical results is only limited by the discreteness of simulations. We then study polycentrism in cities with this tool. Two job centers are in...

  6. Modeling and implementing an agent-based environmental health impact decision support system

    OpenAIRE

    Sokolova, Marina; Fernández Caballero, Antonio

    2009-01-01

    This paper presents an approach to the creation of an agent-based system for the assessment of environmental impact upon human health. As indicators of the environmental impact water pollution, indexes of traffic and industrial activity, wastes and solar radiation are assumed. And as human health indicator morbidity is taken. All the data comprise multiple heterogeneous data repositories. The system is logically and functionally divided into three layers, solving the tasks of information fusi...

  7. Simulating Land-Use Change using an Agent-Based Land Transaction Model

    Science.gov (United States)

    Bakker, M. M.; van Dijk, J.; Alam, S. J.

    2013-12-01

    In the densely populated cultural landscapes of Europe, the vast majority of all land is owned by private parties, be it farmers (the majority), nature organizations, property developers, or citizens. Therewith, the vast majority of all land-use change arises from land transactions between different owner types: successful farms expand at the expense of less successful farms, and meanwhile property developers, individual citizens, and nature organizations also actively purchase land. These land transactions are driven by specific properties of the land, by governmental policies, and by the (economic) motives of both buyers and sellers. Climate/global change can affect these drivers at various scales: at the local scale changes in hydrology can make certain land less or more desirable; at the global scale the agricultural markets will affect motives of farmers to buy or sell land; while at intermediate (e.g. provincial) scales property developers and nature conservationists may be encouraged or discouraged to purchase land. The cumulative result of all these transactions becomes manifest in changing land-use patterns, and consequent environmental responses. Within the project Climate Adaptation for Rural Areas an agent-based land-use model was developed that explores the future response of individual land users to climate change, within the context of wider global change (i.e. policy and market change). It simulates the exchange of land among farmers and between farmers and nature organizations and property developers, for a specific case study area in the east of the Netherlands. Results show that local impacts of climate change can result in a relative stagnation in the land market in waterlogged areas. Furthermore, the increase in dairying at the expense of arable cultivation - as has been observed in the area in the past - is slowing down as arable produce shows a favourable trend in the agricultural world market. Furthermore, budgets for nature managers are

  8. A Spatial-Dynamic Agent-based Model of Energy Crop Introduction in Jiangsu province, China

    Science.gov (United States)

    Shu, K.; Schneider, U. A.; Scheffran, J.

    2012-12-01

    Bioenergy, as one promising option to replace a fraction of conventional fossil fuels and lower net greenhouse gas emissions, has gained many countries', in particular developing ones' attention. Their focus is mainly on the design of efficient bioenergy utilization pathways which adapt to both local geographic features and economic conditions. The establishment of a biomass production sector would be the first and pivotal component in the whole industrial chain. Several existing studies have estimated the global biomass for energy potential but arrived at very different results. One reason for the large uncertainty of biomass potential may be ascribed to the diverse nature of biomass leading to different estimates in different circumstances. Therefore, specific research at the local level is essential. Following this thought, our research conducted in the Jiangsu province, a representative region in China, will explore the spatial distribution of biomass production. The employed methodology can also be applied to other locations both in China and similar developing countries if model parameters are adequately adjusted. In this study, we analyze the local situation in the Jiangsu province focusing on the selection of new energy crops, since the cultivation of dedicated crop for energy use is still in experimental phase. We also examine the land use conflict which is especially relevant to China with more than 1.3 billion people and a severe burden on food supply. We develop an agent-based model to find the optimal spatial distribution of biomass (SDA-SDB) in Jiangsu province. Compromising data accessibility and heterogeneity of environmental factors across the province, we resolve our model at county level and consider the aggregated farming community in one county as a single agent. The aim of SDA-SDB is to simulate farmers' decision process of allocating land to either food or energy crops facing limited resources and political targets for bioenergy development

  9. An Agent-based Strategy for Deploying Analysis Models into Specification and Design for Distributed APS Systems

    OpenAIRE

    Luis Antonio Santa-Eulalia; Sophie D'Amours; Jean-Marc Frayret

    2011-01-01

    Despite the extensive use of the agent technology in the Supply Chain Management field, its integration with Advanced Planning and Scheduling (APS) tools still represents a promising field with several open research questions. Specifically, the literature falls short in providing an integrated framework to analyze, specify, design and implement simulation experiments covering the whole simulation cycle. Thus, this paper proposes an agent-based strategy to convert the 'analysis' models into 's...

  10. Linking Bayesian and agent-based models to simulate complex social-ecological systems in semi-arid regions

    OpenAIRE

    Pope, Aloah J.; Gimblett, Randy

    2015-01-01

    Interdependencies of ecologic, hydrologic, and social systems challenge traditional approaches to natural resource management in semi-arid regions. As a complex social-ecological system, water demands in the Sonoran Desert from agricultural and urban users often conflicts with water needs for its ecologically-significant riparian corridors. To explore this system, we developed an agent-based model to simulate complex feedbacks between human decisions and environmental conditions in the Rio So...

  11. Linking Bayesian and agent-based models to simulate complex social-ecological systems in semi-arid regions

    OpenAIRE

    Pope, Aloah J.; Randy eGimblett

    2015-01-01

    Interdependencies of ecologic, hydrologic, and social systems challenge traditional approaches to natural resource management in semi-arid regions. As a complex social-ecological system, water demands in the Sonoran Desert from agricultural and urban users often conflicts with water needs for its ecologically-significant riparian corridors. To explore this system, we developed an agent-based model to simulate complex feedbacks between human decisions and environmental conditions in the Rio ...

  12. A Unified Multiscale Field/Network/Agent Based Modeling Framework for Human and Ecological Health Risk Analysis

    OpenAIRE

    Georgopoulos, Panos G.; Isukapalli, Sastry S.

    2009-01-01

    A conceptual framework is presented for multiscale field/network/agent-based modeling to support human and ecological health risk assessments. This framework is based on the representation of environmental dynamics in terms of interacting networks, agents that move across different networks, fields representing spatiotemporal distributions of physical properties, rules governing constraints and interactions, and actors that make decisions affecting the state of the system. Different determini...

  13. Deciphering chemokine properties by a hybrid agent-based model of Aspergillus fumigatus infection in human alveoli

    OpenAIRE

    Pollmächer, Johannes; Figge, Marc Thilo

    2015-01-01

    The ubiquitous airborne fungal pathogen Aspergillus fumigatus is inhaled by humans every day. In the lung, it is able to quickly adapt to the humid environment and, if not removed within a time frame of 4–8 h, the pathogen may cause damage by germination and invasive growth. Applying a to-scale agent-based model of human alveoli to simulate early A. fumigatus infection under physiological conditions, we recently demonstrated that alveolar macrophages require chemotactic cues to accomplish the...

  14. Identity in agent-based models : modeling dynamic multiscale social processes.

    Energy Technology Data Exchange (ETDEWEB)

    Ozik, J.; Sallach, D. L.; Macal, C. M.; Decision and Information Sciences; Univ. of Chicago

    2008-07-01

    Identity-related issues play central roles in many current events, including those involving factional politics, sectarianism, and tribal conflicts. Two popular models from the computational-social-science (CSS) literature - the Threat Anticipation Program and SharedID models - incorporate notions of identity (individual and collective) and processes of identity formation. A multiscale conceptual framework that extends some ideas presented in these models and draws other capabilities from the broader CSS literature is useful in modeling the formation of political identities. The dynamic, multiscale processes that constitute and transform social identities can be mapped to expressive structures of the framework

  15. Modeling interdependent socio-technical networks: The smart grid—an agent-based modeling approach

    NARCIS (Netherlands)

    Worm, D.; Langley, D.J.; Becker, J.

    2014-01-01

    The aim of this paper is to improve scientific modeling of interdependent socio-technical networks. In these networks the interplay between technical or infrastructural elements on the one hand and social and behavioral aspects on the other hand, plays an important role. Examples include electricity

  16. Agent-based Modeling Simulation Analysis on the Regulation of Institutional Investor's Encroachment Behavior in Stock Market

    Directory of Open Access Journals (Sweden)

    Yang Li

    2014-05-01

    Full Text Available Purpose: This study explores the effective regulation of institutional investor's encroachment behavior in stock market. Given the theoretical and practical importance, the present study examines the effect of the self-adaptive regulation strategy (adjusting the regulation factors such as punishment and the probability of investigating successfully in time for the sake of the small & medium-sized investor protection.Design/methodology/approach: This study was carried out through game theory and agent-based modeling simulation. Firstly, a dynamic game model was built to search the core factors of regulation and the equilibrium paths. Secondly, an agent-based modeling simulation model was built in Swarm to extend the game model. Finally, a simulation experiment (using virtual parameter values was performed to examine the effect of regulation strategy obtained form game model.Findings: The results of this study showed that the core factors of avoiding the institutional investor's encroachment behavior are the punishment and the probability of investigating successfully of the regulator. The core factors embody as the self-adaptability and the capability of regulator. If the regulator can adjust the regulation factors in time, the illegal behaviors will be avoided effectively.Research limitations/implications: The simulation experiment in this paper was performed with virtual parameter values. Although the results of experiment showed the effect of self-adaptive regulation, there are still some differences between simulation experiment and real market situation.Originality/value: The purpose of this study is to investigate an effective regulation strategy of institutional investor's encroachment behavior in stock market in order to maintain market order and protect the benefits of investors. Base on the game model and simulation model, a simulation experiment was preformed and the result showed that the self-adaptive regulation would be effective

  17. Collaborative Multi-Agent Based Simulations: Stakeholder-Focused Innovation in Water Resources Management and Decision-Support Modeling

    Science.gov (United States)

    Kock, B. E.

    2006-12-01

    The combined use of multi-agent based simulations and collaborative modeling approaches is emerging as a highly effective tool for representing complex coupled social-biophysical water resource systems. A collaboratively-designed, multi-agent based simulation can be used both as a decision-support tool and as a didactic method for improving stakeholder understanding and engagement with water resources policymaking and management. Major technical and non-technical obstacles remain to the efficient and effective development of multi-agent models of human society, to integrating these models with GIS and other numerical models, and to building a process for engaging stakeholders with model design, implementation and use. It is proposed here to tackle some of these obstacles through a collaborative multi-agent based simulation process framework, intended for practical use in resolving disputes and environmental challenges over sustainable irrigated agriculture in the Western United States. A practical implementation of this framework will be conducted in collaboration with a diverse stakeholder group representing farmers and local, state and federal water managers. Through the use of simulation gaming, interviewing and computer-based knowledge elicitation, a multi-agent model representing local and regional social dynamics will be developed to support the acceptable and sustainable implementation of management alternatives for reducing regional problems of salinization and high selenium concentrations in soils and irrigation water. The development of a socially and scientifically credible simulation platform in this setting can make a significant contribution to ensuring the non-adversarial use of high quality science, enhance the engagement of stakeholders with policymaking, and help meet the challenges of integrating dynamic models of human society with more traditional biophysical systems models.

  18. Linking Bayesian and agent-based models to simulate complex social-ecological systems in semi-arid regions

    Directory of Open Access Journals (Sweden)

    Aloah J Pope

    2015-08-01

    Full Text Available Interdependencies of ecologic, hydrologic, and social systems challenge traditional approaches to natural resource management in semi-arid regions. As a complex social-ecological system, water demands in the Sonoran Desert from agricultural and urban users often conflicts with water needs for its ecologically-significant riparian corridors. To explore this system, we developed an agent-based model to simulate complex feedbacks between human decisions and environmental conditions in the Rio Sonora Watershed. Cognitive mapping in conjunction with stakeholder participation produced a Bayesian model of conditional probabilities of local human decision-making processes resulting to changes in water demand. Probabilities created in the Bayesian model were incorporated into the agent-based model, so that each agent had a unique probability to make a positive decision based on its perceived environment at each point in time and space. By using a Bayesian approach, uncertainty in the human decision-making process could be incorporated. The spatially-explicit agent-based model simulated changes in depth-to-groundwater by well pumping based on an agent’s water demand. Changes in depth-to-groundwater feedback to influence agent behavior, as well as determine unique vegetation classes within the riparian corridor. Each vegetation class then provides varying stakeholder-defined quality values of ecosystem services. Using this modeling approach allowed us to examine effects on both the ecological and social system of semi-arid riparian corridors under various scenarios. The insight provided by the model contributes to understanding how specific interventions may alter the complex social-ecological system in the future.

  19. Understanding agent-based models of financial markets: A bottom-up approach based on order parameters and phase diagrams

    Science.gov (United States)

    Lye, Ribin; Tan, James Peng Lung; Cheong, Siew Ann

    2012-11-01

    We describe a bottom-up framework, based on the identification of appropriate order parameters and determination of phase diagrams, for understanding progressively refined agent-based models and simulations of financial markets. We illustrate this framework by starting with a deterministic toy model, whereby N independent traders buy and sell M stocks through an order book that acts as a clearing house. The price of a stock increases whenever it is bought and decreases whenever it is sold. Price changes are updated by the order book before the next transaction takes place. In this deterministic model, all traders based their buy decisions on a call utility function, and all their sell decisions on a put utility function. We then make the agent-based model more realistic, by either having a fraction fb of traders buy a random stock on offer, or a fraction fs of traders sell a random stock in their portfolio. Based on our simulations, we find that it is possible to identify useful order parameters from the steady-state price distributions of all three models. Using these order parameters as a guide, we find three phases: (i) the dead market; (ii) the boom market; and (iii) the jammed market in the phase diagram of the deterministic model. Comparing the phase diagrams of the stochastic models against that of the deterministic model, we realize that the primary effect of stochasticity is to eliminate the dead market phase.

  20. An empirically grounded agent based model for modeling directs, conflict detection and resolution operations in Air Traffic Management

    CERN Document Server

    Bongiorno, C; Mantegna, Rosario N

    2016-01-01

    We present an agent based model of the Air Traffic Management socio-technical complex system that aims at modeling the interactions between aircrafts and air traffic controllers at a tactical level. The core of the model is given by the conflict detection and resolution module and by the directs module. Directs are flight shortcuts that are given by air controllers to speed up the passage of an aircraft within a certain airspace and therefore to facilitate airline operations. Conflicts resolution between flight trajectories can arise during the en-route phase of each flight due to both not detailed flight trajectory planning or unforeseen events that perturb the planned flight plan. Our model performs a local conflict detection and resolution procedure. Once a flight trajectory has been made conflict-free, the model searches for possible improvements of the system efficiency by issuing directs. We give an example of model calibration based on real data. We then provide an illustration of the capability of our...

  1. Agent-based modeling as a research method for exploring joint decision making in organizations – a distributed cognition perspective

    DEFF Research Database (Denmark)

    Thomsen, Svend Erik

    2016-01-01

    This paper proposes an agent-based model to explore aspects of decision making in organizations from a distributed cognition perspective. Within distributed cognition research cognition is conceptualized as a process that takes place - not only within individuals’ minds but also between them...... decision making and distributed cognition......., as they interact with each other. This means that the interactions between individuals impact both the outcome of the decision process and the individuals’ cognition, which in turn will impact their subsequent decisions. The paper outlines how this dynamic and complex task can be modeled taking into account...

  2. Agent based models for testing city evacuation strategies under a flood event as strategy to reduce flood risk

    Science.gov (United States)

    Medina, Neiler; Sanchez, Arlex; Nokolic, Igor; Vojinovic, Zoran

    2016-04-01

    This research explores the uses of Agent Based Models (ABM) and its potential to test large scale evacuation strategies in coastal cities at risk from flood events due to extreme hydro-meteorological events with the final purpose of disaster risk reduction by decreasing human's exposure to the hazard. The first part of the paper corresponds to the theory used to build the models such as: Complex adaptive systems (CAS) and the principles and uses of ABM in this field. The first section outlines the pros and cons of using AMB to test city evacuation strategies at medium and large scale. The second part of the paper focuses on the central theory used to build the ABM, specifically the psychological and behavioral model as well as the framework used in this research, specifically the PECS reference model is cover in this section. The last part of this section covers the main attributes or characteristics of human beings used to described the agents. The third part of the paper shows the methodology used to build and implement the ABM model using Repast-Symphony as an open source agent-based modelling and simulation platform. The preliminary results for the first implementation in a region of the island of Sint-Maarten a Dutch Caribbean island are presented and discussed in the fourth section of paper. The results obtained so far, are promising for a further development of the model and its implementation and testing in a full scale city

  3. Agent-based modeling approach of immune defense against spores of opportunistic human pathogenic fungi

    Directory of Open Access Journals (Sweden)

    Christian eTokarski

    2012-04-01

    Full Text Available Opportunistic human pathogenic fungi like the ubiquitous fungus Aspergillus fumigatus are a majorthreat to immunocompromised patients. An impaired immune system renders the body vulnerable to inva-sive mycoses that often lead to the death of the patient. While the number of immunocompromised patientsis rising with medical progress, the process and dynamics of defence against invaded and ready to germinatefungal conidia are still insufficiently understood.Besides macrophages, neutrophil granulocytes form an important line of defence in that they clear conidia.Live imaging shows the interaction of those phagocytes and conidia as a dynamic process of touching, drag-ging and phagocytosis. To unravel strategies of phagocytes on the hunt for conidia an agent-based modelingapproach is used, implemented in NetLogo. Different modes of movement of phagocytes are tested regard-ing their clearing efficiency: random walk, short term persistence in their recent direction, chemotaxis ofchemokines excreted by conidia and communication between phagocytes.

  4. Service Oriented Architecture for Business Dynamics: An Agent Based Business Modeling Approach

    Directory of Open Access Journals (Sweden)

    O. P. Rishi

    2009-01-01

    Full Text Available In today's rapidly changing environment the industries areinterested in executing business functions that has scope inmultiple applications. Business dynamics and technologicalinnovations have felt organizations to comply with adisparate mix of operating systems, applications anddatabases. This makes it difficult, time-consuming and costlyfor IT departments to deliver new applications that integrateheterogeneous technologies. It demands high interoperabilityand more flexible and adaptive business processmanagement. The inclination is to have systems assembled,from a loosely coupled collection of Web services, which areuniversal and integrated. This technical area appears tohave scope where the Agent Technology can be exploitedwith significant advantages. With Service OrientedArchitecture a decomposable architecture, and associatedset of development and IT management disciplines,composed of loosely coupled services communicating viapre-established protocols, these services can be assembledad-hoc to form customized applications that address a widevariety of business requirements.In the present paper, we propose a conceptual frameworkfor agent-based Service Oriented Architecture (SOA. Inwhich we try to integrate Service Oriented Architecture withthe agent technology & other tactical technologies like webservices, business workflow services, Business meta-rules,search optimization of services and semantic Webtechnology for business service mappings.

  5. Analysis of Interactions of Key Stakeholders on B2C e-Markets - Agent Based Modelling and Simulation Approach

    Directory of Open Access Journals (Sweden)

    Marković Aleksandar

    2016-05-01

    Full Text Available Background/purpose: This paper discusses the application of ABMS - agent-based modelling and simulation in the analysis of customer behaviour on B2C e-commerce websites as well as in the analysis of various business decisions upon the effects of on-line sales. The continuous development and dynamics in the field of e-commerce requires application of advanced decision-making tools. These tools must be able to process, in a short time period, a large amount of data generated by the e-commerce systems and enable the use of acquired data for making quality business decisions.

  6. The role of research efficiency in the evolution of scientific productivity and impact: An agent-based model

    Science.gov (United States)

    You, Zhi-Qiang; Han, Xiao-Pu; Hadzibeganovic, Tarik

    2016-02-01

    We introduce an agent-based model to investigate the effects of production efficiency (PE) and hot field tracing capability (HFTC) on productivity and impact of scientists embedded in a competitive research environment. Agents compete to publish and become cited by occupying the nodes of a citation network calibrated by real-world citation datasets. Our Monte-Carlo simulations reveal that differences in individual performance are strongly related to PE, whereas HFTC alone cannot provide sustainable academic careers under intensely competitive conditions. Remarkably, the negative effect of high competition levels on productivity can be buffered by elevated research efficiency if simultaneously HFTC is sufficiently low.

  7. Improving energy efficiency and smart grid program analysis with agent-based end-use forecasting models

    International Nuclear Information System (INIS)

    Electric utilities and regulators face difficult challenges evaluating new energy efficiency and smart grid programs prompted, in large part, by recent state and federal mandates and financial incentives. It is increasingly difficult to separate electricity use impacts of individual utility programs from the impacts of increasingly stringent appliance and building efficiency standards, increasing electricity prices, appliance manufacturer efficiency improvements, energy program interactions and other factors. This study reviews traditional approaches used to evaluate electric utility energy efficiency and smart-grid programs and presents an agent-based end-use modeling approach that resolves many of the shortcomings of traditional approaches. Data for a representative sample of utility customers in a Midwestern US utility are used to evaluate energy efficiency and smart grid program targets over a fifteen-year horizon. Model analysis indicates that a combination of the two least stringent efficiency and smart grid program scenarios provides peak hour reductions one-third greater than the most stringent smart grid program suggesting that reductions in peak demand requirements are more feasible when both efficiency and smart grid programs are considered together. Suggestions on transitioning from traditional end-use models to agent-based end-use models are provided.

  8. Improving energy efficiency and smart grid program analysis with agent-based end-use forecasting models

    International Nuclear Information System (INIS)

    Electric utilities and regulators face difficult challenges evaluating new energy efficiency and smart grid programs prompted, in large part, by recent state and federal mandates and financial incentives. It is increasingly difficult to separate electricity use impacts of individual utility programs from the impacts of increasingly stringent appliance and building efficiency standards, increasing electricity prices, appliance manufacturer efficiency improvements, energy program interactions and other factors. This study reviews traditional approaches used to evaluate electric utility energy efficiency and smart-grid programs and presents an agent-based end-use modeling approach that resolves many of the shortcomings of traditional approaches. Data for a representative sample of utility customers in a Midwestern US utility are used to evaluate energy efficiency and smart grid program targets over a fifteen-year horizon. Model analysis indicates that a combination of the two least stringent efficiency and smart grid program scenarios provides peak hour reductions one-third greater than the most stringent smart grid program suggesting that reductions in peak demand requirements are more feasible when both efficiency and smart grid programs are considered together. Suggestions on transitioning from traditional end-use models to agent-based end-use models are provided. (author)

  9. Diffusion dynamics and concentration of toxic materials from quantum dots-based nanotechnologies: an agent-based modeling simulation framework

    Energy Technology Data Exchange (ETDEWEB)

    Agusdinata, Datu Buyung, E-mail: bagusdinata@niu.edu; Amouie, Mahbod [Northern Illinois University, Department of Industrial & Systems Engineering and Environment, Sustainability, & Energy Institute (United States); Xu, Tao [Northern Illinois University, Department of Chemistry and Biochemistry (United States)

    2015-01-15

    Due to their favorable electrical and optical properties, quantum dots (QDs) nanostructures have found numerous applications including nanomedicine and photovoltaic cells. However, increased future production, use, and disposal of engineered QD products also raise concerns about their potential environmental impacts. The objective of this work is to establish a modeling framework for predicting the diffusion dynamics and concentration of toxic materials released from Trioctylphosphine oxide-capped CdSe. To this end, an agent-based model simulation with reaction kinetics and Brownian motion dynamics was developed. Reaction kinetics is used to model the stability of surface capping agent particularly due to oxidation process. The diffusion of toxic Cd{sup 2+} ions in aquatic environment was simulated using an adapted Brownian motion algorithm. A calibrated parameter to reflect sensitivity to reaction rate is proposed. The model output demonstrates the stochastic spatial distribution of toxic Cd{sup 2+} ions under different values of proxy environmental factor parameters. With the only chemistry considered was oxidation, the simulation was able to replicate Cd{sup 2+} ion release from Thiol-capped QDs in aerated water. The agent-based method is the first to be developed in the QDs application domain. It adds both simplicity of the solubility and rate of release of Cd{sup 2+} ions and complexity of tracking of individual atoms of Cd at the same time.

  10. Agent-Based Optimization

    CERN Document Server

    Jędrzejowicz, Piotr; Kacprzyk, Janusz

    2013-01-01

    This volume presents a collection of original research works by leading specialists focusing on novel and promising approaches in which the multi-agent system paradigm is used to support, enhance or replace traditional approaches to solving difficult optimization problems. The editors have invited several well-known specialists to present their solutions, tools, and models falling under the common denominator of the agent-based optimization. The book consists of eight chapters covering examples of application of the multi-agent paradigm and respective customized tools to solve  difficult optimization problems arising in different areas such as machine learning, scheduling, transportation and, more generally, distributed and cooperative problem solving.

  11. Emergence of a Snake-Like Structure in Mobile Distributed Agents: An Exploratory Agent-Based Modeling Approach

    Directory of Open Access Journals (Sweden)

    Muaz A. Niazi

    2014-01-01

    Full Text Available The body structure of snakes is composed of numerous natural components thereby making it resilient, flexible, adaptive, and dynamic. In contrast, current computer animations as well as physical implementations of snake-like autonomous structures are typically designed to use either a single or a relatively smaller number of components. As a result, not only these artificial structures are constrained by the dimensions of the constituent components but often also require relatively more computationally intensive algorithms to model and animate. Still, these animations often lack life-like resilience and adaptation. This paper presents a solution to the problem of modeling snake-like structures by proposing an agent-based, self-organizing algorithm resulting in an emergent and surprisingly resilient dynamic structure involving a minimal of interagent communication. Extensive simulation experiments demonstrate the effectiveness as well as resilience of the proposed approach. The ideas originating from the proposed algorithm can not only be used for developing self-organizing animations but can also have practical applications such as in the form of complex, autonomous, evolvable robots with self-organizing, mobile components with minimal individual computational capabilities. The work also demonstrates the utility of exploratory agent-based modeling (EABM in the engineering of artificial life-like complex adaptive systems.

  12. An Agent-Based Computational Model for China’s Stock Market and Stock Index Futures Market

    Directory of Open Access Journals (Sweden)

    Hai-Chuan Xu

    2014-01-01

    Full Text Available This study presents an agent-based computational cross market model for Chinese equity market structure, which includes both stocks and CSI 300 index futures. In this model, we design several stocks and one index future to simulate this structure. This model allows heterogeneous investors to make investment decisions with restrictions including wealth, market trading mechanism, and risk management. Investors’ demands and order submissions are endogenously determined. Our model successfully reproduces several key features of the Chinese financial markets including spot-futures basis distribution, bid-ask spread distribution, volatility clustering, and long memory in absolute returns. Our model can be applied in cross market risk control, market mechanism design, and arbitrage strategies analysis.

  13. Representing the acquisition and use of energy by individuals in agent-based models of animal populations

    DEFF Research Database (Denmark)

    Sibly, RS; Grimm, Volker; Johnston, Alice S.A.;

    2013-01-01

    individual energy budgets is essential for realistic modelling of populations affected by food availability. Such ABMs are already being used to guide conservation planning of nature reserves and shell fisheries, to assess environmental impacts of building proposals including wind farms and highways......Agent-based models (ABMs) are widely used to predict how populations respond to changing environments. As the availability of food varies in space and time, individuals should have their own energy budgets, but there is no consensus as to how these should be modelled. Here, we use knowledge...... of physiological ecology to identify major issues confronting the modeller and to make recommendations about how energy budgets for use in ABMs should be constructed. Our proposal is that modelled animals forage as necessary to supply their energy needs for maintenance, growth and reproduction...

  14. MODELING OF INVESTMENT STRATEGIES IN STOCKS MARKETS: AN APPROACH FROM MULTI AGENT BASED SIMULATION AND FUZZY LOGIC

    Directory of Open Access Journals (Sweden)

    ALEJANDRO ESCOBAR

    2010-01-01

    Full Text Available This paper presents a simulation model of a complex system, in this case a financial market, using a MultiAgent Based Simulation approach. Such model takes into account microlevel aspects like the Continuous Double Auction mechanism, which is widely used within stock markets, as well as investor agents reasoning who participate looking for profits. To model such reasoning several variables were considered including general stocks information like profitability and volatility, but also some agent's aspects like their risk tendency. All these variables are incorporated throughout a fuzzy logic approach trying to represent in a faithful manner the kind of reasoning that nonexpert investors have, including a stochastic component in order to model human factors.

  15. Incorporating GIS data into an agent-based model to support planning policy making for the development of creative industries

    Science.gov (United States)

    Liu, Helin; Silva, Elisabete A.; Wang, Qian

    2016-07-01

    This paper presents an extension to the agent-based model "Creative Industries Development-Urban Spatial Structure Transformation" by incorporating GIS data. Three agent classes, creative firms, creative workers and urban government, are considered in the model, and the spatial environment represents a set of GIS data layers (i.e. road network, key housing areas, land use). With the goal to facilitate urban policy makers to draw up policies locally and optimise the land use assignment in order to support the development of creative industries, the improved model exhibited its capacity to assist the policy makers conducting experiments and simulating different policy scenarios to see the corresponding dynamics of the spatial distributions of creative firms and creative workers across time within a city/district. The spatiotemporal graphs and maps record the simulation results and can be used as a reference by the policy makers to adjust land use plans adaptively at different stages of the creative industries' development process.

  16. A georeferenced Agent-Based Model to analyze the climate change impacts on the Andorra winter tourism

    CERN Document Server

    Pons-Pons, M; Rosas-Casals, M; Sureda, B; Jover, E

    2011-01-01

    This study presents a georeferenced agent-based model to analyze the climate change impacts on the ski industry in Andorra and the effect of snowmaking as future adaptation strategy. The present study is the first attempt to analyze the ski industry in the Pyrenees region and will contribute to a better understanding of the vulnerability of Andorran ski resorts and the suitability of snowmaking as potential adaptation strategy to climate change. The resulting model can be used as a planning support tool to help local stakeholders understand the vulnerability and potential impacts of climate change. This model can be used in the decision-making process of designing and developing appropriate sustainable adaptation strategies to future climate variability.

  17. Environmental Sustainability and Effects on Urban Micro Region using Agent-Based Modeling of Urbanisation in Select Major Indian Cities

    Science.gov (United States)

    Aithal, B. H.

    2015-12-01

    Abstract: Urbanisation has gained momentum with globalization in India. Policy decisions to set up commercial, industrial hubs have fuelled large scale migration, added with population upsurge has contributed to the fast growing urban region that needs to be monitored in order to design sustainable urban cities. Unplanned urbanization have resulted in the growth of peri-urban region referred to as urban sprawl, are often devoid of basic amenities and infrastructure leading to large scale environmental problems that are evident. Remote sensing data acquired through space borne sensors at regular interval helps in understanding urban dynamics aided by Geoinformatics which has proved very effective in mapping and monitoring for sustainable urban planning. Cellular automata (CA) is a robust approach for the spatially explicit simulation of land-use land cover dynamics. CA uses rules, states, conditions that are vital factors in modelling urbanisation. This communication effectively introduces simulation assistances of CA with the agent based modelling supported by its fuzzy characteristics and weightages through analytical hierarchal process (AHP). This has been done considering perceived agents such as industries, natural resource etc. Respective agent's role in development of a particular regions into an urban area has been examined with weights and its influence of each of these agents based on its characteristics functions. Validation was performed obtaining a high kappa coefficient indicating the quality and the allocation performance of the model & validity of the model to predict future projections. The prediction using the proposed model was performed for 2030. Further environmental sustainability of each of these cities are explored such as water features, environment, greenhouse gas emissions, effects on human human health etc., Modeling suggests trend of various land use classes transformation with the spurt in urban expansions based on specific regions and

  18. Toward an agent-based patient-physician model for the adoption of continuous glucose monitoring technology.

    Science.gov (United States)

    Verella, J Tipan; Patek, Stephen D

    2009-03-01

    Health care is a major component of the U.S. economy, and tremendous research and development efforts are directed toward new technologies in this arena. Unfortunately few tools exist for predicting outcomes associated with new medical products, including whether new technologies will find widespread use within the target population. Questions of technology adoption are rife within the diabetes technology community, and we particularly consider the long-term prognosis for continuous glucose monitoring (CGM) technology. We present an approach to the design and analysis of an agent model that describes the process of CGM adoption among patients with type 1 diabetes mellitus (T1DM), their physicians, and related stakeholders. We particularly focus on patient-physician interactions, with patients discovering CGM technology through word-of-mouth communication and through advertising, applying pressure to their physicians in the context of CGM device adoption, and physicians, concerned about liability, looking to peers for a general level of acceptance of the technology before recommending CGM to their patients. Repeated simulation trials of the agent-based model show that the adoption process reflects the heterogeneity of the adopting community. We also find that the effect of the interaction between patients and physicians is agents. Each physician, say colored by the nature of the environment as defined by the model parameters. We find that, by being able to represent the diverse perspectives of different types of stakeholders, agent-based models can offer useful insights into the adoption process. Models of this sort may eventually prove to be useful in helping physicians, other health care providers, patient advocacy groups, third party payers, and device manufacturers understand the impact of their decisions about new technologies.

  19. Phenotypic transition maps of 3D breast acini obtained by imaging-guided agent-based modeling

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Jonathan; Enderling, Heiko; Becker-Weimann, Sabine; Pham, Christopher; Polyzos, Aris; Chen, Chen-Yi; Costes, Sylvain V

    2011-02-18

    We introduce an agent-based model of epithelial cell morphogenesis to explore the complex interplay between apoptosis, proliferation, and polarization. By varying the activity levels of these mechanisms we derived phenotypic transition maps of normal and aberrant morphogenesis. These maps identify homeostatic ranges and morphologic stability conditions. The agent-based model was parameterized and validated using novel high-content image analysis of mammary acini morphogenesis in vitro with focus on time-dependent cell densities, proliferation and death rates, as well as acini morphologies. Model simulations reveal apoptosis being necessary and sufficient for initiating lumen formation, but cell polarization being the pivotal mechanism for maintaining physiological epithelium morphology and acini sphericity. Furthermore, simulations highlight that acinus growth arrest in normal acini can be achieved by controlling the fraction of proliferating cells. Interestingly, our simulations reveal a synergism between polarization and apoptosis in enhancing growth arrest. After validating the model with experimental data from a normal human breast line (MCF10A), the system was challenged to predict the growth of MCF10A where AKT-1 was overexpressed, leading to reduced apoptosis. As previously reported, this led to non growth-arrested acini, with very large sizes and partially filled lumen. However, surprisingly, image analysis revealed a much lower nuclear density than observed for normal acini. The growth kinetics indicates that these acini grew faster than the cells comprising it. The in silico model could not replicate this behavior, contradicting the classic paradigm that ductal carcinoma in situ is only the result of high proliferation and low apoptosis. Our simulations suggest that overexpression of AKT-1 must also perturb cell-cell and cell-ECM communication, reminding us that extracellular context can dictate cellular behavior.

  20. Frequency analysis of tick quotes on the foreign exchange market and agent-based modeling: A spectral distance approach

    CERN Document Server

    Sato, A H

    2006-01-01

    The high frequency financial data of the foreign exchange market (EUR/CHF, EUR/GBP, EUR/JPY, EUR/NOK, EUR/SEK, EUR/USD, NZD/USD, USD/CAD, USD/CHF, USD/JPY, USD/NOK, and USD/SEK) are analyzed by utilizing the Kullback-Leibler divergence between two normalized spectrograms of the tick frequency. We detect and characterize temporal structure variations of the similarity between currency pairs. A simple agent-based model that N market participants exchange M currency pairs is proposed. The equation for the tick frequency is approximately derived in the theoretical manner. From the analysis of this model the spectral distance of the tick frequency is associated with the similarity of behavior (perception and decision) of the market participants to exchange these currency pairs.

  1. Entrainment and Control of Bacterial Populations: An in Silico Study over a Spatially Extended Agent Based Model.

    Science.gov (United States)

    Mina, Petros; Tsaneva-Atanasova, Krasimira; Bernardo, Mario di

    2016-07-15

    We extend a spatially explicit agent based model (ABM) developed previously to investigate entrainment and control of the emergent behavior of a population of synchronized oscillating cells in a microfluidic chamber. Unlike most of the work in models of control of cellular systems which focus on temporal changes, we model individual cells with spatial dependencies which may contribute to certain behavioral responses. We use the model to investigate the response of both open loop and closed loop strategies, such as proportional control (P-control), proportional-integral control (PI-control) and proportional-integral-derivative control (PID-control), to heterogeinities and growth in the cell population, variations of the control parameters and spatial effects such as diffusion in the spatially explicit setting of a microfluidic chamber setup. We show that, as expected from the theory of phase locking in dynamical systems, open loop control can only entrain the cell population in a subset of forcing periods, with a wide variety of dynamical behaviors obtained outside these regions of entrainment. Closed-loop control is shown instead to guarantee entrainment in a much wider region of control parameter space although presenting limitations when the population size increases over a certain threshold. In silico tracking experiments are also performed to validate the ability of classical control approaches to achieve other reference behaviors such as a desired constant output or a linearly varying one. All simulations are carried out in BSim, an advanced agent-based simulator of microbial population which is here extended ad hoc to include the effects of control strategies acting onto the population. PMID:27110835

  2. Towards a dynamic assessment of raw materials criticality: Linking agent-based demand — With material flow supply modelling approaches

    Energy Technology Data Exchange (ETDEWEB)

    Knoeri, Christof, E-mail: c.knoeri@leeds.ac.uk [Sustainability Research Institute, School of Earth and Environment, University of Leeds, LS5 9JT Leeds (United Kingdom); Wäger, Patrick A.; Stamp, Anna; Althaus, Hans-Joerg [Technology and Society Laboratory, Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Duebendorf (Switzerland); Weil, Marcel [Institute for Technology Assessment and Systems Analysis, Karlsruhe Institute of Technology (KIT), D-76021 Karlsruhe (Germany); Helmholtz-Institute Ulm for Electrochemical Energy Storage, Albert-Einstein-Allee 11, 89081 Ulm (Germany)

    2013-09-01

    Emerging technologies such as information and communication-, photovoltaic- or battery technologies are expected to increase significantly the demand for scarce metals in the near future. The recently developed methods to evaluate the criticality of mineral raw materials typically provide a ‘snapshot’ of the criticality of a certain material at one point in time by using static indicators both for supply risk and for the impacts of supply restrictions. While allowing for insights into the mechanisms behind the criticality of raw materials, these methods cannot account for dynamic changes in products and/or activities over time. In this paper we propose a conceptual framework intended to overcome these limitations by including the dynamic interactions between different possible demand and supply configurations. The framework integrates an agent-based behaviour model, where demand emerges from individual agent decisions and interaction, into a dynamic material flow model, representing the materials' stocks and flows. Within the framework, the environmental implications of substitution decisions are evaluated by applying life-cycle assessment methodology. The approach makes a first step towards a dynamic criticality assessment and will enhance the understanding of industrial substitution decisions and environmental implications related to critical metals. We discuss the potential and limitation of such an approach in contrast to state-of-the-art methods and how it might lead to criticality assessments tailored to the specific circumstances of single industrial sectors or individual companies. - Highlights: ► Current criticality assessment methods provide a ‘snapshot’ at one point in time. ► They do not account for dynamic interactions between demand and supply. ► We propose a conceptual framework to overcomes these limitations. ► The framework integrates an agent-based behaviour model with a dynamic material flow model. ► The approach proposed

  3. Towards a dynamic assessment of raw materials criticality: Linking agent-based demand — With material flow supply modelling approaches

    International Nuclear Information System (INIS)

    Emerging technologies such as information and communication-, photovoltaic- or battery technologies are expected to increase significantly the demand for scarce metals in the near future. The recently developed methods to evaluate the criticality of mineral raw materials typically provide a ‘snapshot’ of the criticality of a certain material at one point in time by using static indicators both for supply risk and for the impacts of supply restrictions. While allowing for insights into the mechanisms behind the criticality of raw materials, these methods cannot account for dynamic changes in products and/or activities over time. In this paper we propose a conceptual framework intended to overcome these limitations by including the dynamic interactions between different possible demand and supply configurations. The framework integrates an agent-based behaviour model, where demand emerges from individual agent decisions and interaction, into a dynamic material flow model, representing the materials' stocks and flows. Within the framework, the environmental implications of substitution decisions are evaluated by applying life-cycle assessment methodology. The approach makes a first step towards a dynamic criticality assessment and will enhance the understanding of industrial substitution decisions and environmental implications related to critical metals. We discuss the potential and limitation of such an approach in contrast to state-of-the-art methods and how it might lead to criticality assessments tailored to the specific circumstances of single industrial sectors or individual companies. - Highlights: ► Current criticality assessment methods provide a ‘snapshot’ at one point in time. ► They do not account for dynamic interactions between demand and supply. ► We propose a conceptual framework to overcomes these limitations. ► The framework integrates an agent-based behaviour model with a dynamic material flow model. ► The approach proposed makes

  4. Between Complexity and Parsimony: Can Agent-Based Modelling Resolve the Trade-off

    DEFF Research Database (Denmark)

    Nielsen, Helle Ørsted; Malawska, Anna Katarzyna

    2013-01-01

    While Herbert Simon espoused development of general models of behavior, he also strongly advo-cated that these models be based on realistic assumptions about humans and therefore reflect the complexity of human cognition and social systems (Simon 1997). Hence, the model of bounded rationality is ...

  5. Particle Swarm Social Adaptive Model for Multi-Agent Based Insurgency Warfare Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Xiaohui [ORNL; Potok, Thomas E [ORNL

    2009-12-01

    To better understand insurgent activities and asymmetric warfare, a social adaptive model for modeling multiple insurgent groups attacking multiple military and civilian targets is proposed and investigated. This report presents a pilot study using the particle swarm modeling, a widely used non-linear optimal tool to model the emergence of insurgency campaign. The objective of this research is to apply the particle swarm metaphor as a model of insurgent social adaptation for the dynamically changing environment and to provide insight and understanding of insurgency warfare. Our results show that unified leadership, strategic planning, and effective communication between insurgent groups are not the necessary requirements for insurgents to efficiently attain their objective.

  6. The EMO-Model: An Agent-Based Model of Primate Social Behavior Regulated by Two Emotional Dimensions, Anxiety-FEAR and Satisfaction-LIKE

    NARCIS (Netherlands)

    Evers, Ellen; de Vries, Han; Spruijt, Berry; Sterck, Elisabeth

    2014-01-01

    Agent-based models provide a promising tool to investigate the relationship between individuals’ behavior and emerging group-level patterns. An individual’s behavior may be regulated by its emotional state and its interaction history with specific individuals. Emotional bookkeeping is a candidate me

  7. Approach and development strategy for an agent-based model of economic confidence.

    Energy Technology Data Exchange (ETDEWEB)

    Sprigg, James A.; Pryor, Richard J.; Jorgensen, Craig Reed

    2004-08-01

    We are extending the existing features of Aspen, a powerful economic modeling tool, and introducing new features to simulate the role of confidence in economic activity. The new model is built from a collection of autonomous agents that represent households, firms, and other relevant entities like financial exchanges and governmental authorities. We simultaneously model several interrelated markets, including those for labor, products, stocks, and bonds. We also model economic tradeoffs, such as decisions of households and firms regarding spending, savings, and investment. In this paper, we review some of the basic principles and model components and describe our approach and development strategy for emulating consumer, investor, and business confidence. The model of confidence is explored within the context of economic disruptions, such as those resulting from disasters or terrorist events.

  8. Agent-based modeling of zapping behavior of viewers, television commercial allocation, and advertisement markets

    OpenAIRE

    Kyan, Hiroyuki; Inoue, Jun-ichi

    2013-01-01

    We propose a simple probabilistic model of zapping behavior of television viewers. Our model might be regarded as a `theoretical platform' to investigate the human collective behavior in the macroscopic scale through the zapping action of each viewer at the microscopic level. The stochastic process of audience measurements as macroscopic quantities such as television program rating point or the so-called gross rating point (GRP for short) are reconstructed using the microscopic modeling of ea...

  9. Investigating social conflicts linked to water resources trhough agent-based modelling

    OpenAIRE

    Saqalli, Mehdi; Thiriot, Samuel; Amblard, Frederic

    2010-01-01

    International audience Over the next decades, natural resources and water resources in particular are likely to be one of the major origins of social conflicts. To date however, no model enables the study of coupled dynamics of hydrology, water use and social conflicts. Building such a model requires identifying the key concepts, entities and processes that are present in much field cases and have to be included into the model. The research presented in this paper takes place in a more gen...

  10. Independence and interdependence in collective decision making: an agent-based model of nest-site choice by honeybee swarms.

    Science.gov (United States)

    List, Christian; Elsholtz, Christian; Seeley, Thomas D

    2009-03-27

    Condorcet's jury theorem shows that when the members of a group have noisy but independent information about what is best for the group as a whole, majority decisions tend to outperform dictatorial ones. When voting is supplemented by communication, however, the resulting interdependencies between decision makers can strengthen or undermine this effect: they can facilitate information pooling, but also amplify errors. We consider an intriguing non-human case of independent information pooling combined with communication: the case of nest-site choice by honeybee (Apis mellifera) swarms. It is empirically well documented that when there are different nest sites that vary in quality, the bees usually choose the best one. We develop a new agent-based model of the bees' decision process and show that its remarkable reliability stems from a particular interplay of independence and interdependence between the bees.

  11. Modeling urban expansion policy scenarios using an agent-based approach for Guangzhou Metropolitan Region of China

    Directory of Open Access Journals (Sweden)

    Guangjin Tian

    2014-09-01

    Full Text Available Policy makers and the human decision processes of urban planning have an impact on urban expansion. The behaviors and decision modes of regional authority, real estate developer, resident, and farmer agents and their interactions can be simulated by the analytical hierarchy process (AHP method. The driving factors are regressed with urban dynamics instead of static land-use types. Agents’ behaviors and decision modes have an impact on the urban dynamic pattern by adjusting parameter weights. We integrate an agent-based model (ABM with AHP to investigate a complex decision-making process and future urban dynamic processes. Three policy scenarios for baseline development, rapid development, and green land protection have been applied to predict the future development patterns of the Guangzhou metropolitan region. A future policy scenario analysis can help policy makers to understand the possible results. These individuals can adjust their policies and decisions according to their different objectives.

  12. Understanding the relationship between safety investment and safety performance of construction projects through agent-based modeling.

    Science.gov (United States)

    Lu, Miaojia; Cheung, Clara Man; Li, Heng; Hsu, Shu-Chien

    2016-09-01

    The construction industry in Hong Kong increased its safety investment by 300% in the past two decades; however, its accident rate has plateaued to around 50% for one decade. Against this backdrop, researchers have found inconclusive results on the causal relationship between safety investment and safety performance. Using agent-based modeling, this study takes an unconventional bottom-up approach to study safety performance on a construction site as an outcome of a complex system defined by interactions among a worksite, individual construction workers, and different safety investments. Instead of focusing on finding the absolute relationship between safety investment and safety performance, this study contributes to providing a practical framework to investigate how different safety investments interacting with different parameters such as human and environmental factors could affect safety performance. As a result, we could identify cost-effective safety investments under different construction scenarios for delivering optimal safety performance.

  13. Understanding the relationship between safety investment and safety performance of construction projects through agent-based modeling.

    Science.gov (United States)

    Lu, Miaojia; Cheung, Clara Man; Li, Heng; Hsu, Shu-Chien

    2016-09-01

    The construction industry in Hong Kong increased its safety investment by 300% in the past two decades; however, its accident rate has plateaued to around 50% for one decade. Against this backdrop, researchers have found inconclusive results on the causal relationship between safety investment and safety performance. Using agent-based modeling, this study takes an unconventional bottom-up approach to study safety performance on a construction site as an outcome of a complex system defined by interactions among a worksite, individual construction workers, and different safety investments. Instead of focusing on finding the absolute relationship between safety investment and safety performance, this study contributes to providing a practical framework to investigate how different safety investments interacting with different parameters such as human and environmental factors could affect safety performance. As a result, we could identify cost-effective safety investments under different construction scenarios for delivering optimal safety performance. PMID:27240124

  14. Multi-agent based modeling and execution framework for complex simulation, control and measuring tasks

    NARCIS (Netherlands)

    Papp, Z.; Hoeve, H.J.

    2000-01-01

    The paper presents a modeling concept and a supporting runtime environment, which enables running simulation, control and measuring (data processing) tasks on distributed implementation platforms. Its main features: (1) it is scaleable in various application domains; (2) it has a model based system

  15. Building agent-based simulations using structural and process mental models

    NARCIS (Netherlands)

    Stuit, Marco; Szirbik, Nick; Wortmann, Hans; Negru,; Jebelean, T; Petcu, D; Zaharie, D

    2007-01-01

    This paper provides a design rationale for a mechanism that enforces a correct mapping between a model of a nested agent organization and a model of a composite interaction-based business process. We use an example of a collaborative process to illustrate the features of this mechanism. The mapping

  16. Theory of agent-based market models with controlled levels of greed and anxiety

    International Nuclear Information System (INIS)

    We use generating functional analysis to study minority-game-type market models with generalized strategy valuation updates that control the psychology of agents' actions. The agents' choice between trend-following and contrarian trading, and their vigor in each, depends on the overall state of the market. Even in 'fake history' models, the theory now involves an effective overall bid process (coupled to the effective agent process) which can exhibit profound remanence effects and new phase transitions. For some models the bid process can be solved directly, others require Maxwell-construction-type approximations.

  17. Biomimetic agent based modelling using male Frog calling behaviour as a case study

    DEFF Research Database (Denmark)

    Jørgensen, Søren V.; Demazeau, Yves; Christensen-Dalsgaard, Jakob;

    2014-01-01

    by individuals to generate their observed population behaviour. A number of existing agent-modelling frameworks are considered, but none have the ability to handle large numbers of time-dependent event-generating agents; hence the construction of a new tool, RANA. The calling behaviour of the Puerto Rican Tree...... Frog, E. coqui, is implemented as a case study for the presentation and discussion of the tool, and results from this model are presented. RANA, in its present stage of development, is shown to be able to handle the problem of modelling calling frogs, and several fruitful extensions are proposed...

  18. Theory of agent-based market models with controlled levels of greed and anxiety

    Energy Technology Data Exchange (ETDEWEB)

    Papadopoulos, P; Coolen, A C C [Department of Mathematics, King' s College London, The Strand, London WC2R 2LS (United Kingdom)], E-mail: panagiotis.2.papadopoulos@kcl.ac.uk, E-mail: ton.coolen@kcl.ac.uk

    2010-01-15

    We use generating functional analysis to study minority-game-type market models with generalized strategy valuation updates that control the psychology of agents' actions. The agents' choice between trend-following and contrarian trading, and their vigor in each, depends on the overall state of the market. Even in 'fake history' models, the theory now involves an effective overall bid process (coupled to the effective agent process) which can exhibit profound remanence effects and new phase transitions. For some models the bid process can be solved directly, others require Maxwell-construction-type approximations.

  19. Agent-based modeling of zapping behavior of viewers, television commercial allocation, and advertisement markets

    CERN Document Server

    Kyan, Hiroyuki

    2013-01-01

    We propose a simple probabilistic model of zapping behavior of television viewers. Our model might be regarded as a `theoretical platform' to investigate the human collective behavior in the macroscopic scale through the zapping action of each viewer at the microscopic level. The stochastic process of audience measurements as macroscopic quantities such as television program rating point or the so-called gross rating point (GRP for short) are reconstructed using the microscopic modeling of each viewer's decision making. Assuming that each viewer decides the television station to watch by means of three factors, namely, physical constraints on television controllers, exogenous information such as advertisement of program by television station, and endogenous information given by `word-of-mouth communication' through the past market history, we shall construct an aggregation probability of Gibbs-Boltzmann-type with the energy function. We discuss the possibility for the ingredients of the model system to exhibi...

  20. Citizenship and Power in an Agent-based Model of Tax Compliance with Public Expenditure

    OpenAIRE

    Paolo Pellizzari; Dino Rizzi

    2012-01-01

    In this paper we present a model of tax compliance with heterogeneous agents who maximize their individual utility based on income and the conjectured level of per capita public expenditure. We formally include psychological drivers in this model. These drivers affect individual behavior, such as risk aversion, together with appreciation of public expenditure, expectations about peers� compliance and a natural inclination to comply, all of which we summarize in a quality termed �citizenship�....

  1. Role-Playing Games and Agent-Based Models in Lower Amudarya

    OpenAIRE

    Abrami, G.

    2009-01-01

    Cemagref is participating in Newater WP3 & WP2.5 by providing modelling support for the Uzbekistan test case. This work has been carried on in collaboration with the coordinator of Uzbekistan case study Maja Schlueter, from UFZ, and Neela Matin, from York University. The idea was to use a companion modelling approach both to gain understanding on Water User Associations (WUAs) ability to cope with water stress and to set up a collaborative working context in these WUAs in Khorezm (irrigation)...

  2. Modeling of agent-based complex network under cyber-violence

    Science.gov (United States)

    Huang, Chuanchao; Hu, Bin; Jiang, Guoyin; Yang, Ruixian

    2016-09-01

    Public opinion reversal arises frequently in modern society, due to the continual interactions between individuals and their surroundings. To explore the underlying mechanism of the interesting social phenomenon, we introduce here a new model which takes the relationship between the individual cognitive bias and their corresponding choice behavior into account. Experimental results show that the proposed model can provide an accurate description of the entire process of public opinion reversal under the internet environment and the distribution of cognitive bias plays the role of a measure for the reversal probability. In particular, the application to cyber violence, a typical example of public opinion reversal, suggests that public opinion is prone to be seriously affected by the spread of misleading and harmful information. Furthermore, our model is very robust and thus can be employed to other empirical studies that concern the sudden change of public and personal opinion on internet.

  3. An Agent-Based Model for Navigation Simulation in a Heterogeneous Environment

    Science.gov (United States)

    Shanklin, Teresa A.

    2012-01-01

    Complex navigation (e.g. indoor and outdoor environments) can be studied as a system-of-systems problem. The model is made up of disparate systems that can aid a user in navigating from one location to another, utilizing whatever sensor system or information is available. By using intelligent navigation sensors and techniques (e.g. RFID, Wifi,…

  4. Agent-Based Modeling in Supply Chain Management:A Genetic Algorithm and Fuzzy Logic Approach

    Directory of Open Access Journals (Sweden)

    Meriem DJENNAS

    2012-09-01

    Full Text Available In today’s global market, reaching a competitive advantage by integrating firms in a supply chain management strategy becomes a key success for any firm seeking to survive in a complex environment. However, as interactions among agents in the supply chain management (SCM remain unpredictable, simulation appears as a powerful tool aiming to predict market behavior and agents’ performance levels. This paper discusses the issues of supply chain management and the requirements for supply chain simulation modeling. It reviews the relationships amongArtificial Intelligence (AI and SCM and concludes that under some conditions, SCM models exhibit some inadequacies that may be enriched by the use of AI tools. This approach aims to test the supply chain activities of nine companies in the crude oil market. The objective is to tackle the issues under which agents can coexist in a competitive environment. Furthermore, we will specify the supply chain management trading interaction amongagents by using an optimization approach based on a Genetic Algorithm (AG, Clustering and Fuzzy Logic (FL.Results support the view that the structured model provides a good tool for modeling the supply chain activities using AI methodology.

  5. Agent-Based Modeling in Supply Chain Management:A Genetic Algorithm and Fuzzy Logic Approach

    Directory of Open Access Journals (Sweden)

    Meriem Djennas

    2012-10-01

    Full Text Available In today’s global market, reaching a competitive advantage by integrating firms in a supply chainmanagement strategy becomes a key success for any firm seeking to survive in a complex environment.However, as interactions among agents in the supply chain management (SCM remain unpredictable,simulation appears as a powerful tool aiming to predict market behavior and agents’ performance levels.This paper discusses the issues of supply chain management and the requirements for supply chainsimulation modeling. It reviews the relationships amongArtificial Intelligence (AI and SCM and concludesthat under some conditions, SCM models exhibit some inadequacies that may be enriched by the use of AItools. This approach aims to test the supply chain activities of nine companies in the crude oil market. Theobjective is to tackle the issues under which agents can coexist in a competitive environment. Furthermore,we will specify the supply chain management trading interaction amongagents by using an optimizationapproach based on a Genetic Algorithm (AG, Clustering and Fuzzy Logic (FL.Results support the viewthat the structured model provides a good tool for modeling the supply chain activities using AImethodology.

  6. Agent-based model of intermittent renewables: Simulating emerging changes in energy markets in transition

    NARCIS (Netherlands)

    Chappin, E.J.L.; Viebahn, P.; Richstein, J.C.; Lechtenböhmer, S.; Nebel, A.

    2012-01-01

    The energy transition is taking shape in the German and, to a lesser extent also its neighbouring electricity markets. We have proposed adaptations to an existing model to represent the increasing shares of intermittent renewables, that may alter the structure of the market and the viability of stra

  7. A secure model for mobile agent based on encrypted circuit construction

    Institute of Scientific and Technical Information of China (English)

    ZHENG Yan; WANG Ruchuan; MU Hong; WANG Haiyan

    2007-01-01

    As a new technology,mobile agent (MA) shows a wide application in the field of network technology.However,security has been one of the crucial problems in its application.A new protection model based on a trusted element is presented in this paper.The trusted element,which differs from the traditional trusted hardware such as a smart card or a co-processor,offers a third party service based on an encrypted circuit construction.The procedure of constructing an encrypted circuit is introduced and the method of using the trusted service to protect the MA is also described.An application example is given to show how to use the new model at the end of the paper.

  8. The critical properties of the agent-based model with environmental-economic interactions

    Science.gov (United States)

    Kuscsik, Z.; Horváth, D.

    2008-05-01

    The steady-state and nonequilibrium properties of the model of environmental-economic interactions are studied. The interacting heterogeneous agents are simulated on the platform of the emission dynamics of cellular automaton. The diffusive emissions are produced by the factory agents, and the local pollution is monitored by the randomly walking (mobile) sensors. When the threshold concentration is exceeded, a feedback signal is transmitted from the sensor to the nearest factory that affects its actual production rate. The model predicts the discontinuous phase transition between safe and catastrophic ecology. Right at the critical line, the broad-scale power-law distributions of emission rates have been identified. The power-law fluctuations are triggered by the screening effect of factories and by the time delay between the environment contamination and its detection. The system shows the typical signs of the self-organized critical systems, such as power-law distributions and scaling laws.

  9. The contagious nature of imprisonment: an agent-based model to explain racial disparities in incarceration rates.

    Science.gov (United States)

    Lum, Kristian; Swarup, Samarth; Eubank, Stephen; Hawdon, James

    2014-09-01

    We build an agent-based model of incarceration based on the susceptible-infected-suspectible (SIS) model of infectious disease propagation. Our central hypothesis is that the observed racial disparities in incarceration rates between Black and White Americans can be explained as the result of differential sentencing between the two demographic groups. We demonstrate that if incarceration can be spread through a social influence network, then even relatively small differences in sentencing can result in large disparities in incarceration rates. Controlling for effects of transmissibility, susceptibility and influence network structure, our model reproduces the observed large disparities in incarceration rates given the differences in sentence lengths for White and Black drug offenders in the USA without extensive parameter tuning. We further establish the suitability of the SIS model as applied to incarceration by demonstrating that the observed structural patterns of recidivism are an emergent property of the model. In fact, our model shows a remarkably close correspondence with California incarceration data. This work advances efforts to combine the theories and methods of epidemiology and criminology.

  10. A brucellosis disease control strategy for the Kakheti region of the country of Georgia: an agent-based model.

    Science.gov (United States)

    Havas, K A; Boone, R B; Hill, A E; Salman, M D

    2014-06-01

    Brucellosis has been reported in livestock and humans in the country of Georgia with Brucella melitensis as the most common species causing disease. Georgia lacked sufficient data to assess effectiveness of the various potential control measures utilizing a reliable population-based simulation model of animal-to-human transmission of this infection. Therefore, an agent-based model was built using data from previous studies to evaluate the effect of an animal-level infection control programme on human incidence and sheep flock and cattle herd prevalence of brucellosis in the Kakheti region of Georgia. This model simulated the patterns of interaction of human-animal workers, sheep flocks and cattle herds with various infection control measures and returned population-based data. The model simulates the use of control measures needed for herd and flock prevalence to fall below 2%. As per the model output, shepherds had the greatest disease reduction as a result of the infection control programme. Cattle had the greatest influence on the incidence of human disease. Control strategies should include all susceptible animal species, sheep and cattle, identify the species of brucellosis present in the cattle population and should be conducted at the municipality level. This approach can be considered as a model to other countries and regions when assessment of control strategies is needed but data are scattered.

  11. An agent-based model of innovation diffusion: network structure and coexistence under different information regimes

    OpenAIRE

    Pegoretti, Giovanni; Rentocchini,Francesco; Vittucci Marzetti, Giuseppe

    2012-01-01

    The paper analyzes how the structure of social networks affects innovation diffusion and competition under different information regimes. Diffusion is modeled as the result of idiosyncratic adoption thresholds, local network effects and information diffusion (broadcasting and demonstration effect from previous adopters). A high social cohesion decreases the probability of one innovation cornering the market. Nonetheless, with imperfect information, in small-world networks the higher speed of ...

  12. Developing an Agent-Based Model to Simulate Urban Land-Use Expansion (Case Study: Qazvin)

    OpenAIRE

    F. Nourian; A. A. Alesheikh; F. Hosseinali

    2012-01-01

    Extended abstract1-IntroductionUrban land-use expansion is a challenging issue in developing countries. Increases in population as well as the immigration from the villages to the cities are the two major factors for that phenomenon. Those factors have reduced the influence of efforts that try to limit the cities’ boundaries. Thus, spatial planners always look for the models that simulate the expansion of urban land-uses and enable them to prevent unbalanced expansions of cities and guide the...

  13. Agent Based Modelling for Water Resource Allocation in the Transboundary Nile River

    OpenAIRE

    Ning Ding; Rasool Erfani; Hamid Mokhtar; Tohid Erfani

    2016-01-01

    Water resource allocation is the process of assessing and determining a mechanism on how water should be distributed among different regions, sectors and users. Over the recent decades, the optimal solution for water resource allocation has been explored both in centralised and decentralised mechanisms. Conventional approaches are under central planner suggesting a solution which maximises total welfare to the users. Moving towards the decentralised modelling, the techniques consider individu...

  14. Effects of diversification among assets in an agent-based market model

    CERN Document Server

    Ghoulmié, F; Mellen, C P; Di Matteo, T

    2007-01-01

    We extend to the multi-asset case the framework of a discrete time model of a single asset financial market developed in Ghoulmie et al (2005). In particular, we focus on adaptive agents with threshold behavior allocating their resources among two assets. We explore numerically the effect of this diversification as an additional source of complexity in the financial market and we discuss its destabilizing role. We also point out the relevance of these studies for financial decision making.

  15. Modeling of the Cloud Interconnected Human Friendly Multi-Agent Based Sustainable Power Controller

    OpenAIRE

    Gricius, G.; Drungilas, D.; Guseinovaitė, J.; Grigaitis, K.; Bielskis, A. A.

    2013-01-01

    The paper presents model of the cloud interconnected multi-agent human friendly sustainable power controller (Controller). The Controller is based on the human ambient comfort affect reward index (ACAR index). The ACAR index depends on human physiological parameters: the temperature, the ECG- electrocardiogram and the EDA-electro-dermal activity. These physiological parameters are used for sustainable power control by multi-agent system developed as the cloud interconnected, instrumented, and...

  16. Tele-Immersive Interaction with Intelligent Virtual Agents Based on Real-Time 3D Modeling

    Directory of Open Access Journals (Sweden)

    Shujun Zhang

    2012-02-01

    Full Text Available To enable intelligent agents interacting smoothly with human users, researchers have been deploying novel interaction modalities (e.g. non-verbal cue, vision and touch in addition to agents’ conversational skills. Models of multi-modality interaction can enhance agents’ real-time perception, cognition and reaction towards the user. In this paper we report a novel tele-immersive interaction system developed using real-time 3D modelling techniques. In such system user’s full body is reconstructed using multi-view cameras and CUDA based visual hull reconstruction algorithm. User’s mesh model is then loaded into a virtual environment for interacting with an autonomous agent. Technical details and initial results of the system are illustrated in this paper. Following that a novel interaction scenario is proposed which links the virtual agent with a remote physical robot who takes the role of mediating interactions between two geographically separated users. Finally we discuss in depth the implications of such human-agent interaction and possible future improvements and directions.

  17. Simulating non-small cell lung cancer with a multiscale agent-based model

    Directory of Open Access Journals (Sweden)

    Deisboeck Thomas S

    2007-12-01

    Full Text Available Abstract Background The epidermal growth factor receptor (EGFR is frequently overexpressed in many cancers, including non-small cell lung cancer (NSCLC. In silico modeling is considered to be an increasingly promising tool to add useful insights into the dynamics of the EGFR signal transduction pathway. However, most of the previous modeling work focused on the molecular or the cellular level only, neglecting the crucial feedback between these scales as well as the interaction with the heterogeneous biochemical microenvironment. Results We developed a multiscale model for investigating expansion dynamics of NSCLC within a two-dimensional in silico microenvironment. At the molecular level, a specific EGFR-ERK intracellular signal transduction pathway was implemented. Dynamical alterations of these molecules were used to trigger phenotypic changes at the cellular level. Examining the relationship between extrinsic ligand concentrations, intrinsic molecular profiles and microscopic patterns, the results confirmed that increasing the amount of available growth factor leads to a spatially more aggressive cancer system. Moreover, for the cell closest to nutrient abundance, a phase-transition emerges where a minimal increase in extrinsic ligand abolishes the proliferative phenotype altogether. Conclusion Our in silico results indicate that in NSCLC, in the presence of a strong extrinsic chemotactic stimulus (and depending on the cell's location downstream EGFR-ERK signaling may be processed more efficiently, thereby yielding a migration-dominant cell phenotype and overall, an accelerated spatio-temporal expansion rate.

  18. Agent-based models for latent liquidity and concave price impact

    Science.gov (United States)

    Mastromatteo, Iacopo; Tóth, Bence; Bouchaud, Jean-Philippe

    2014-04-01

    We revisit the "ɛ-intelligence" model of Tóth et al. [Phys. Rev. X 1, 021006 (2011), 10.1103/PhysRevX.1.021006], which was proposed as a minimal framework to understand the square-root dependence of the impact of meta-orders on volume in financial markets. The basic idea is that most of the daily liquidity is "latent" and furthermore vanishes linearly around the current price, as a consequence of the diffusion of the price itself. However, the numerical implementation of Tóth et al. (2011) was criticized as being unrealistic, in particular because all the "intelligence" was conferred to market orders, while limit orders were passive and random. In this work, we study various alternative specifications of the model, for example, allowing limit orders to react to the order flow or changing the execution protocols. By and large, our study lends strong support to the idea that the square-root impact law is a very generic and robust property that requires very few ingredients to be valid. We also show that the transition from superdiffusion to subdiffusion reported in Tóth et al. (2011) is in fact a crossover but that the original model can be slightly altered in order to give rise to a genuine phase transition, which is of interest on its own. We finally propose a general theoretical framework to understand how a nonlinear impact may appear even in the limit where the bias in the order flow is vanishingly small.

  19. Integrating Unlocking of Organizational Paths into an Agent-Based Simulation Model

    OpenAIRE

    Obschonka, Felix

    2014-01-01

    Das Berliner Drei-Phasen-Modell pfadabhängiger Prozesse erklärt, wie die Handlungsfähigkeit von Organisationen aufgrund selbstverstärkender Effekte eingeschränkt werden kann. Das Phänomen Pfadbruch, bei welchem Organisationen etablierte Pfade verlassen, wird darin nur unzureichend beschrieben. Obwohl in der Managementliteratur verschiedene Möglichkeiten zum Aufbrechen von Pfadabhängigkeiten diskutiert werden, fehlt eine systematische Überprüfung, ob und wie organisationale Pfade geb...

  20. An Agent-based approach to modelling integrated product teams undertaking a design activity.

    OpenAIRE

    Sim, Yee Wai; Crowder, Richard; Robinson, Mark; Hughes, Helen

    2009-01-01

    The interactions between individual designers, within integrated product teams, and the nature of design tasks, all have a significant impact upon how well a design task can be performed, and hence the quality of the resultant product and the time in which it can be delivered. In this paper we describe an ongoing research project which aims to model integrated product teams through the use of multi-agent systems. We first describe the background and rationale for our work, and then present ou...

  1. Parochial Altruists or Ideologues? An Agent Based Model of Commitment to Self Sacrifice

    Directory of Open Access Journals (Sweden)

    Giti Zahedzadeh

    2015-09-01

    Full Text Available 'What motivates suicide attackers remains an open question. From an evolutionary perspective, commitment to suicide missions is puzzling since such behavior is fitness reducing. We model suicide terrorism by drawing on two fundamental human motivations: altruism and selfishness. Martyrdom can be viewed as altruistic- benefiting group members at a cost to oneself, as well as selfish- ideological belief in a profitable afterlife. Our simulations identify that some degree of both behaviors are essential in order to facilitate a commitment to sacrifice. Thus, manipulations of ideology and altruism can tip the threshold and set the agents on the path of martyrdom. '

  2. A Procedure for Building Product Models in Intelligent Agent-based OperationsManagement

    DEFF Research Database (Denmark)

    Hvam, Lars; Riis, Jesper; Malis, Martin;

    2003-01-01

    This article presents a procedure for building product models to support the specification processes dealing with sales, design of product variants and production preparation. The procedure includes, as the first phase, an analysis and redesign of the business processes that are to be supported...... for the business processes they support, and properly structured and documented in order to facilitate the maintenance and further development of the systems. The research has been carried out at the Centre for Industrialisation of Engineering, Department of Manufacturing Engineering, Technical University...

  3. Towards an Agent-based Model for Demand-Responsive Transport Serving Thin Flows

    OpenAIRE

    CICH, Glenn; Knapen, Luk; Galland, S.; Vuurstaek, Jan; Neven, An; BELLEMANS, Tom

    2016-01-01

    Low volume traveler flows cause problems for public transportation (PT) providers. The Smart-PT project aims to find out how such flows can be combined to increase the service provider viability. The capability to conceive multi-modal trips is fundamental in that context and is modeled by the Trip Sequence Composer (TSC) concept. A TSC is an essential component of the traveler’s brain, of the customer support operated by collective transport providers, of trip advisers in websites etc. We pre...

  4. Reduction of error influence in a crisis: Agent-based modeling

    Directory of Open Access Journals (Sweden)

    Danijela D. Protić

    2012-01-01

    Full Text Available Crises caused by human or system errors vary in intensity and duration, and may cause adverse changes in the functioning of an organization. The prevention as well as a good response to incidents and fast reaction to the crisis when it escalates are essential. Therefore, all decisions during the crisis must be precise and concise, and the reaction of the information and communication systems as well as that of personnel must be adequate. The agent technology described in this paper is used to model the education agent for establishing, maintaining and upgrading IT systems, as well as for the staff training. The education agent consists of an indicator of changes in the environment (status indication agent and a management system (management agent for the reaction to crises. Through an illustrative example of the VORG organization, the functions of these agents are described.

  5. Agent-based models of strategies for the emergence and evolution of grammatical agreement.

    Science.gov (United States)

    Beuls, Katrien; Steels, Luc

    2013-01-01

    Grammatical agreement means that features associated with one linguistic unit (for example number or gender) become associated with another unit and then possibly overtly expressed, typically with morphological markers. It is one of the key mechanisms used in many languages to show that certain linguistic units within an utterance grammatically depend on each other. Agreement systems are puzzling because they can be highly complex in terms of what features they use and how they are expressed. Moreover, agreement systems have undergone considerable change in the historical evolution of languages. This article presents language game models with populations of agents in order to find out for what reasons and by what cultural processes and cognitive strategies agreement systems arise. It demonstrates that agreement systems are motivated by the need to minimize combinatorial search and semantic ambiguity, and it shows, for the first time, that once a population of agents adopts a strategy to invent, acquire and coordinate meaningful markers through social learning, linguistic self-organization leads to the spontaneous emergence and cultural transmission of an agreement system. The article also demonstrates how attested grammaticalization phenomena, such as phonetic reduction and conventionalized use of agreement markers, happens as a side effect of additional economizing principles, in particular minimization of articulatory effort and reduction of the marker inventory. More generally, the article illustrates a novel approach for studying how key features of human languages might emerge.

  6. Agent-based models of strategies for the emergence and evolution of grammatical agreement.

    Directory of Open Access Journals (Sweden)

    Katrien Beuls

    Full Text Available Grammatical agreement means that features associated with one linguistic unit (for example number or gender become associated with another unit and then possibly overtly expressed, typically with morphological markers. It is one of the key mechanisms used in many languages to show that certain linguistic units within an utterance grammatically depend on each other. Agreement systems are puzzling because they can be highly complex in terms of what features they use and how they are expressed. Moreover, agreement systems have undergone considerable change in the historical evolution of languages. This article presents language game models with populations of agents in order to find out for what reasons and by what cultural processes and cognitive strategies agreement systems arise. It demonstrates that agreement systems are motivated by the need to minimize combinatorial search and semantic ambiguity, and it shows, for the first time, that once a population of agents adopts a strategy to invent, acquire and coordinate meaningful markers through social learning, linguistic self-organization leads to the spontaneous emergence and cultural transmission of an agreement system. The article also demonstrates how attested grammaticalization phenomena, such as phonetic reduction and conventionalized use of agreement markers, happens as a side effect of additional economizing principles, in particular minimization of articulatory effort and reduction of the marker inventory. More generally, the article illustrates a novel approach for studying how key features of human languages might emerge.

  7. A three-state kinetic agent-based model to analyze tax evasion dynamics

    Science.gov (United States)

    Crokidakis, Nuno

    2014-11-01

    In this work we study the problem of tax evasion on a fully-connected population. For this purpose, we consider that the agents may be in three different states, namely honest tax payers, tax evaders and undecided, that are individuals in an intermediate class among honests and evaders. Every individual can change his/her state following a kinetic exchange opinion dynamics, where the agents interact by pairs with competitive negative (with probability q) and positive (with probability 1-q) couplings, representing agreement/disagreement between pairs of agents. In addition, we consider the punishment rules of the Zaklan econophysics model, for which there is a probability pa of an audit each agent is subject to in every period and a length of time k detected tax evaders remain honest. Our results suggest that below the critical point qc=1/4 of the opinion dynamics the compliance is high, and the punishment rules have a small effect in the population. On the other hand, for q>qc the tax evasion can be considerably reduced by the enforcement mechanism. We also discuss the impact of the presence of the undecided agents in the evolution of the system.

  8. Modelling Inductive Charging of Battery Electric Vehicles using an Agent-Based Approach

    Directory of Open Access Journals (Sweden)

    Zain Ul Abedin

    2014-09-01

    Full Text Available The introduction of battery electric vehicles (BEVs could help to reduce dependence on fossil fuels and emissions from transportation and as such increase energy security and foster sustainable use of energy resources. However a major barrier to the introduction of BEVs is their limited battery capacity and long charging durations. To address these issues of BEVs several solutions are proposed such as battery swapping and fast charging stations. However apart from these stationary modes of charging, recently a new mode of charging has been introduced which is called inductive charging. This allows charging of BEVs as they drive along roads without the need of plugs, using induction. But it is unclear, if and how such technology could be utilized best. In order to investigate the possible impact of the introduction of such inductive charging infrastructure, its potential and its optimal placement, a framework for simulating BEVs using a multi-agent transport simulation was used. This framework was extended by an inductive charging module and initial test runs were performed. In this paper we present the simulation results of these preliminary tests together with analysis which suggests that battery sizes of BEVs could be reduced even if inductive charging technology is implemented only at a small number of high traffic volume links. The paper also demonstrates that our model can effectively support policy and decision making for deploying inductive charging infrastructure.

  9. Exploring the cooperative regimes in an agent-based model: indirect reciprocity vs. selfish incentives

    Science.gov (United States)

    Fort, H.

    2003-08-01

    The self-organization in cooperative regimes in a simple mean-field version of a model based on “selfish” agents which play the Prisoner's Dilemma (PD) game is studied. The agents have no memory and use strategies not based on direct reciprocity nor “tags”. Two variables are assigned to each agent k at time t, measuring its capital C( k; t) and its probability of cooperation p( k; t). At each time step t a pair of agents interact by playing the PD game. These two agents update their probability of cooperation p( k; t) as follows: they compare the profits they made in this interaction δC( k; t) with an estimator ε( k; t) and, if δC( k; t)⩾ ε( k; t), agent i increases its p( k; t) while if δC( k; t)punishment)-are analyzed. It turns out that for all these 24 possibilities, after a transient, the system self-organizes into a stationary state with average equilibrium probability of cooperation p¯∞= constant>0 . Depending on the payoff matrix, there are different equilibrium states characterized by their average probability of cooperation and average equilibrium per capita income ( p¯∞, δC¯∞) .

  10. Memory Transmission in Small Groups and Large Networks: An Agent-Based Model.

    Science.gov (United States)

    Luhmann, Christian C; Rajaram, Suparna

    2015-12-01

    The spread of social influence in large social networks has long been an interest of social scientists. In the domain of memory, collaborative memory experiments have illuminated cognitive mechanisms that allow information to be transmitted between interacting individuals, but these experiments have focused on small-scale social contexts. In the current study, we took a computational approach, circumventing the practical constraints of laboratory paradigms and providing novel results at scales unreachable by laboratory methodologies. Our model embodied theoretical knowledge derived from small-group experiments and replicated foundational results regarding collaborative inhibition and memory convergence in small groups. Ultimately, we investigated large-scale, realistic social networks and found that agents are influenced by the agents with which they interact, but we also found that agents are influenced by nonneighbors (i.e., the neighbors of their neighbors). The similarity between these results and the reports of behavioral transmission in large networks offers a major theoretical insight by linking behavioral transmission to the spread of information.

  11. A Q-learning agent-based model for the analysis of the power market dynamics

    International Nuclear Information System (INIS)

    The introduction of deregulation in the electricity sector resulted in a different way of thinking and acting on the part of producers. Power suppliers strive to maximize their profit and their utilization rate through a bidding process. According to the pricing system, the competition conditions, the demand side bidding, and the available information, they develop different bidding strategies in order to exploit every possible advantage. This paper presents the Q-Learning algorithm in order to model the bidding strategy of suppliers in electricity auctions. The study examined players' behaviour in the spot market and the change in their policy under different conditions of demand. The Q-learning algorithm considers a novel approach to the definition of states and actions. States are not defined exclusively, as states of the environment, but rather, are different for each agent and relative to the impact the environment has on the agent. Actions are not represented by the price the agent bids, but by the variation between the previous and the new bid price. Market structure was described in this paper and the supplier's bidding problem was formulated in terms of Q-learning. A description of the test system was presented and the parameter selection of the algorithm, as well as the presentation and the results of four case study simulations were discussed. The Q-learning algorithm in supplier bidding strategy showed very promising results. it was suggested that the research should be expanded to include more producers or tests of transmission systems. 9 refs., 2 tabs., 6 figs

  12. Policy Research Using Agent-Based Modeling to Assess Future Impacts of Urban Expansion into Farmlands and Forests

    Directory of Open Access Journals (Sweden)

    Stanley V. Gregory

    2008-06-01

    Full Text Available The expansion of urban land uses into farmlands and forests requires an assessment of future ecological impacts. Spatially explicit agent-based models can represent the changes in resilience and ecological services that result from different land-use policies. When modeling complex adaptive systems, both the methods used to interpret results and the standards of rigor used to judge adequacy are complicated and require additional research. Recent studies suggest that it would be appropriate to use these models as an extension of exploratory analysis. This type of analysis generates ensembles of alternate plausible representations of future system conditions. User expertise steers interactive, stepwise system exploration toward inductive reasoning about potential changes to the system. In this study, we develop understanding of the potential alternative futures for a social-ecological system by way of successive simulations that test variations in the types and numbers of policies. The model addresses the agricultural-urban interface and the preservation of ecosystem services. The landscape analyzed is at the junction of the McKenzie and Willamette Rivers adjacent to the cities of Eugene and Springfield in Lane County, Oregon. Our exploration of alternative future scenarios suggests that policies that constrain urban growth and create incentives for farming and forest enterprises to preserve and enhance habitat can protect ecosystem resilience and services.

  13. FishMORPH - An agent-based model to predict salmonid growth and distribution responses under natural and low flows.

    Science.gov (United States)

    Phang, S C; Stillman, R A; Cucherousset, J; Britton, J R; Roberts, D; Beaumont, W R C; Gozlan, R E

    2016-01-01

    Predicting fish responses to modified flow regimes is becoming central to fisheries management. In this study we present an agent-based model (ABM) to predict the growth and distribution of young-of-the-year (YOY) and one-year-old (1+) Atlantic salmon and brown trout in response to flow change during summer. A field study of a real population during both natural and low flow conditions provided the simulation environment and validation patterns. Virtual fish were realistic both in terms of bioenergetics and feeding. We tested alternative movement rules to replicate observed patterns of body mass, growth rates, stretch distribution and patch occupancy patterns. Notably, there was no calibration of the model. Virtual fish prioritising consumption rates before predator avoidance replicated observed growth and distribution patterns better than a purely maximising consumption rule. Stream conditions of low predation and harsh winters provide ecological justification for the selection of this behaviour during summer months. Overall, the model was able to predict distribution and growth patterns well across both natural and low flow regimes. The model can be used to support management of salmonids by predicting population responses to predicted flow impacts and associated habitat change. PMID:27431787

  14. Using uncertainty and sensitivity analyses in socioecological agent-based models to improve their analytical performance and policy relevance.

    Directory of Open Access Journals (Sweden)

    Arika Ligmann-Zielinska

    Full Text Available Agent-based models (ABMs have been widely used to study socioecological systems. They are useful for studying such systems because of their ability to incorporate micro-level behaviors among interacting agents, and to understand emergent phenomena due to these interactions. However, ABMs are inherently stochastic and require proper handling of uncertainty. We propose a simulation framework based on quantitative uncertainty and sensitivity analyses to build parsimonious ABMs that serve two purposes: exploration of the outcome space to simulate low-probability but high-consequence events that may have significant policy implications, and explanation of model behavior to describe the system with higher accuracy. The proposed framework is applied to the problem of modeling farmland conservation resulting in land use change. We employ output variance decomposition based on quasi-random sampling of the input space and perform three computational experiments. First, we perform uncertainty analysis to improve model legitimacy, where the distribution of results informs us about the expected value that can be validated against independent data, and provides information on the variance around this mean as well as the extreme results. In our last two computational experiments, we employ sensitivity analysis to produce two simpler versions of the ABM. First, input space is reduced only to inputs that produced the variance of the initial ABM, resulting in a model with output distribution similar to the initial model. Second, we refine the value of the most influential input, producing a model that maintains the mean of the output of initial ABM but with less spread. These simplifications can be used to 1 efficiently explore model outcomes, including outliers that may be important considerations in the design of robust policies, and 2 conduct explanatory analysis that exposes the smallest number of inputs influencing the steady state of the modeled system.

  15. Investigating Impacts of Alternative Crop Market Scenarios on Land Use Change with an Agent-Based Model

    Directory of Open Access Journals (Sweden)

    Deng Ding

    2015-11-01

    Full Text Available We developed an agent-based model (ABM to simulate farmers’ decisions on crop type and fertilizer application in response to commodity and biofuel crop prices. Farm profit maximization constrained by farmers’ profit expectations for land committed to biofuel crop production was used as the decision rule. Empirical parameters characterizing farmers’ profit expectations were derived from an agricultural landowners and operators survey and integrated in the ABM. The integration of crop production cost models and the survey information in the ABM is critical to producing simulations that can provide realistic insights into agricultural land use planning and policy making. Model simulations were run with historical market prices and alternative market scenarios for corn price, soybean to corn price ratio, switchgrass price, and switchgrass to corn stover ratio. The results of the comparison between simulated cropland percentage and crop rotations with satellite-based land cover data suggest that farmers may be underestimating the effects that continuous corn production has on yields. The simulation results for alternative market scenarios based on a survey of agricultural land owners and operators in the Clear Creek Watershed in eastern Iowa show that farmers see cellulosic biofuel feedstock production in the form of perennial grasses or corn stover as a more risky enterprise than their current crop production systems, likely because of market and production risks and lock in effects. As a result farmers do not follow a simple farm-profit maximization rule.

  16. Evaluating the Impacts of an Agricultural Water Market in the Guadalupe River Basin, Texas: An Agent-based Modeling Approach

    Science.gov (United States)

    Du, E.; Cai, X.; Minsker, B. S.

    2014-12-01

    Agriculture comprises about 80 percent of the total water consumption in the US. Under conditions of water shortage and fully committed water rights, market-based water allocations could be promising instruments for agricultural water redistribution from marginally profitable areas to more profitable ones. Previous studies on water market have mainly focused on theoretical or statistical analysis. However, how water users' heterogeneous physical attributes and decision rules about water use and water right trading will affect water market efficiency has been less addressed. In this study, we developed an agent-based model to evaluate the benefits of an agricultural water market in the Guadalupe River Basin during drought events. Agricultural agents with different attributes (i.e., soil type for crops, annual water diversion permit and precipitation) are defined to simulate the dynamic feedback between water availability, irrigation demand and water trading activity. Diversified crop irrigation rules and water bidding rules are tested in terms of crop yield, agricultural profit, and water-use efficiency. The model was coupled with a real-time hydrologic model and run under different water scarcity scenarios. Preliminary results indicate that an agricultural water market is capable of increasing crop yield, agricultural profit, and water-use efficiency. This capability is more significant under moderate drought scenarios than in mild and severe drought scenarios. The water market mechanism also increases agricultural resilience to climate uncertainty by reducing crop yield variance in drought events. The challenges of implementing an agricultural water market under climate uncertainty are also discussed.

  17. Real-Time Agent-Based Modeling Simulation with in-situ Visualization of Complex Biological Systems

    Science.gov (United States)

    Seekhao, Nuttiiya; Shung, Caroline; JaJa, Joseph; Mongeau, Luc; Li-Jessen, Nicole Y. K.

    2016-01-01

    We present an efficient and scalable scheme for implementing agent-based modeling (ABM) simulation with In Situ visualization of large complex systems on heterogeneous computing platforms. The scheme is designed to make optimal use of the resources available on a heterogeneous platform consisting of a multicore CPU and a GPU, resulting in minimal to no resource idle time. Furthermore, the scheme was implemented under a client-server paradigm that enables remote users to visualize and analyze simulation data as it is being generated at each time step of the model. Performance of a simulation case study of vocal fold inflammation and wound healing with 3.8 million agents shows 35× and 7× speedup in execution time over single-core and multi-core CPU respectively. Each iteration of the model took less than 200 ms to simulate, visualize and send the results to the client. This enables users to monitor the simulation in real-time and modify its course as needed. PMID:27547508

  18. Design and Analysis of Cost-Efficient Sensor Deployment for Tracking Small UAS with Agent-Based Modeling

    Directory of Open Access Journals (Sweden)

    Sangmi Shin

    2016-04-01

    Full Text Available Recently, commercial unmanned aerial systems (UAS have gained popularity. However, these UAS are potential threats to people in terms of safety in public places, such as public parks or stadiums. To reduce such threats, we consider a design, modeling, and evaluation of a cost-efficient sensor system that detects and tracks small UAS. In this research, we focus on discovering the best sensor deployments by simulating different types and numbers of sensors in a designated area, which provide reasonable detection rates at low costs. Also, the system should cover the crowded areas more thoroughly than vacant areas to reduce direct threats to people underneath. This research study utilized the Agent-Based Modeling (ABM technique to model a system consisting of independent and heterogeneous agents that interact with each other. Our previous work presented the ability to apply ABM to analyze the sensor configurations with two types of radars in terms of cost-efficiency. The results from the ABM simulation provide a list of candidate configurations and deployments that can be referred to for applications in the real world environment.

  19. Non-lethal control of the cariogenic potential of an agent-based model for dental plaque.

    Directory of Open Access Journals (Sweden)

    David A Head

    Full Text Available Dental caries or tooth decay is a prevalent global disease whose causative agent is the oral biofilm known as plaque. According to the ecological plaque hypothesis, this biofilm becomes pathogenic when external challenges drive it towards a state with a high proportion of acid-producing bacteria. Determining which factors control biofilm composition is therefore desirable when developing novel clinical treatments to combat caries, but is also challenging due to the system complexity and the existence of multiple bacterial species performing similar functions. Here we employ agent-based mathematical modelling to simulate a biofilm consisting of two competing, distinct types of bacterial populations, each parameterised by their nutrient uptake and aciduricity, periodically subjected to an acid challenge resulting from the metabolism of dietary carbohydrates. It was found that one population was progressively eliminated from the system to give either a benign or a pathogenic biofilm, with a tipping point between these two fates depending on a multiplicity of factors relating to microbial physiology and biofilm geometry. Parameter sensitivity was quantified by individually varying the model parameters against putative experimental measures, suggesting non-lethal interventions that can favourably modulate biofilm composition. We discuss how the same parameter sensitivity data can be used to guide the design of validation experiments, and argue for the benefits of in silico modelling in providing an additional predictive capability upstream from in vitro experiments.

  20. Using agent based modeling to assess the effect of increased Bus Rapid Transit system infrastructure on walking for transportation.

    Science.gov (United States)

    Lemoine, Pablo D; Cordovez, Juan Manuel; Zambrano, Juan Manuel; Sarmiento, Olga L; Meisel, Jose D; Valdivia, Juan Alejandro; Zarama, Roberto

    2016-07-01

    The effect of transport infrastructure on walking is of interest to researchers because it provides an opportunity, from the public policy point of view, to increase physical activity (PA). We use an agent based model (ABM) to examine the effect of transport infrastructure on walking. Particular relevance is given to assess the effect of the growth of the Bus Rapid Transit (BRT) system in Bogotá on walking. In the ABM agents are assigned a home, work location, and socioeconomic status (SES) based on which they are assigned income for transportation. Individuals must decide between the available modes of transport (i.e., car, taxi, bus, BRT, and walking) as the means of reaching their destination, based on resources and needed travel time. We calibrated the model based on Bogota's 2011 mobility survey. The ABM results are consistent with previous empirical findings, increasing BRT access does indeed increase the number of minutes that individuals walk for transportation, although this effect also depends on the availability of other transport modes. The model indicates a saturation process: as more BRT lanes are added, the increment in minutes walking becomes smaller, and eventually the walking time decreases. Our findings on the potential contribution of the expansion of the BRT system to walking for transportation suggest that ABMs may prove helpful in designing policies to continue promoting walking. PMID:27012602

  1. Dynamic impact of social stratification and social influence on smoking prevalence by gender: An agent-based model.

    Science.gov (United States)

    Chao, Dingding; Hashimoto, Hideki; Kondo, Naoki

    2015-12-01

    Smoking behavior is tightly related to socioeconomic status and gender, though the dynamic and non-linear association of smoking prevalence across socioeconomic status and gender groups has not been fully examined. With a special focus on gender-bound differences in the susceptibility to social influence of surrounding others' behaviors, we developed an agent-based model to explore how socioeconomic disparity between and within gender groups affects changes in smoking prevalence. Our developed base model reasonably reproduced the actual trend changes by gender groups over the past 5 years in Japan. Counterfactual experiments with the developed model revealed that closing within- and between-gender disparities in socioeconomic status had a limited impact on reducing smoking prevalence. To the contrary, greater socioeconomic disparity facilitated the reduction in prevalence among males, but it impeded that reduction in females. The counterfactual scenario with equalizing gender-bound susceptibility to social influence among women to men's level showed a dramatic reduction in female prevalence without changing the reduction in male prevalence. Simulation results may provide alternative explanation of the growing disparity in smoking prevalence despite improved welfare equality observed in many developed countries, and suggest that redistribution policies may have side effects of widening health gap. Instead, social policy to reduce social pressures to smoking and support interventions to enhance resilience to the pressure targeting the vulnerable population (in this study, women) would be a more effective strategy in combating the tobacco epidemic and closing the health gap.

  2. Dynamic impact of social stratification and social influence on smoking prevalence by gender: An agent-based model.

    Science.gov (United States)

    Chao, Dingding; Hashimoto, Hideki; Kondo, Naoki

    2015-12-01

    Smoking behavior is tightly related to socioeconomic status and gender, though the dynamic and non-linear association of smoking prevalence across socioeconomic status and gender groups has not been fully examined. With a special focus on gender-bound differences in the susceptibility to social influence of surrounding others' behaviors, we developed an agent-based model to explore how socioeconomic disparity between and within gender groups affects changes in smoking prevalence. Our developed base model reasonably reproduced the actual trend changes by gender groups over the past 5 years in Japan. Counterfactual experiments with the developed model revealed that closing within- and between-gender disparities in socioeconomic status had a limited impact on reducing smoking prevalence. To the contrary, greater socioeconomic disparity facilitated the reduction in prevalence among males, but it impeded that reduction in females. The counterfactual scenario with equalizing gender-bound susceptibility to social influence among women to men's level showed a dramatic reduction in female prevalence without changing the reduction in male prevalence. Simulation results may provide alternative explanation of the growing disparity in smoking prevalence despite improved welfare equality observed in many developed countries, and suggest that redistribution policies may have side effects of widening health gap. Instead, social policy to reduce social pressures to smoking and support interventions to enhance resilience to the pressure targeting the vulnerable population (in this study, women) would be a more effective strategy in combating the tobacco epidemic and closing the health gap. PMID:26610078

  3. Agent based modeling of the effects of potential treatments over the blood-brain barrier in multiple sclerosis.

    Science.gov (United States)

    Pennisi, Marzio; Russo, Giulia; Motta, Santo; Pappalardo, Francesco

    2015-12-01

    Multiple sclerosis is a disease of the central nervous system that involves the destruction of the insulating sheath of axons, causing severe disabilities. Since the etiology of the disease is not yet fully understood, the use of novel techniques that may help to understand the disease, to suggest potential therapies and to test the effects of candidate treatments is highly advisable. To this end we developed an agent based model that demonstrated its ability to reproduce the typical oscillatory behavior observed in the most common form of multiple sclerosis, relapsing-remitting multiple sclerosis. The model has then been used to test the potential beneficial effects of vitamin D over the disease. Many scientific studies underlined the importance of the blood-brain barrier and of the mechanisms that influence its permeability on the development of the disease. In the present paper we further extend our previously developed model with a mechanism that mimics the blood-brain barrier behavior. The goal of our work is to suggest the best strategies to follow for developing new potential treatments that intervene in the blood-brain barrier. Results suggest that the best treatments should potentially prevent the opening of the blood-brain barrier, as treatments that help in recovering the blood-brain barrier functionality could be less effective. PMID:26343337

  4. Design and Analysis of Cost-Efficient Sensor Deployment for Tracking Small UAS with Agent-Based Modeling.

    Science.gov (United States)

    Shin, Sangmi; Park, Seongha; Kim, Yongho; Matson, Eric T

    2016-01-01

    Recently, commercial unmanned aerial systems (UAS) have gained popularity. However, these UAS are potential threats to people in terms of safety in public places, such as public parks or stadiums. To reduce such threats, we consider a design, modeling, and evaluation of a cost-efficient sensor system that detects and tracks small UAS. In this research, we focus on discovering the best sensor deployments by simulating different types and numbers of sensors in a designated area, which provide reasonable detection rates at low costs. Also, the system should cover the crowded areas more thoroughly than vacant areas to reduce direct threats to people underneath. This research study utilized the Agent-Based Modeling (ABM) technique to model a system consisting of independent and heterogeneous agents that interact with each other. Our previous work presented the ability to apply ABM to analyze the sensor configurations with two types of radars in terms of cost-efficiency. The results from the ABM simulation provide a list of candidate configurations and deployments that can be referred to for applications in the real world environment. PMID:27110790

  5. Agent-based modeling for the landuse change of hunter-gather societies and the impacts on biodiversity in Guyana

    Science.gov (United States)

    Iwamura, T.; Fragoso, J.; Lambin, E.

    2012-12-01

    The interactions with animals are vital to the Amerindian, indigenous people, of Rupunini savannah-forest in Guyana. Their connections extend from basic energy and protein resource to spiritual bonding through "paring" to a certain animal in the forest. We collected extensive dataset of 23 indigenous communities for 3.5 years, consisting 9900 individuals from 1307 households, as well as animal observation data in 8 transects per communities (47,000 data entries). In this presentation, our research interest is to model the driver of land use change of the indigenous communities and its impacts on the ecosystem in the Rupunini area under global change. Overarching question we would like to answer with this program is to find how and why "tipping-point" from hunting gathering society to the agricultural society occurs in the future. Secondary question is what is the implication of the change to agricultural society in terms of biodiversity and carbon stock in the area, and eventually the well-being of Rupunini people. To answer the questions regarding the society shift in agriculture activities, we built as simulation with Agent-Based Modeling (Multi Agents Simulation). We developed this simulation by using Netlogo, the programming environment specialized for spatially explicit agent-based modeling (ABM). This simulation consists of four different process in the Rupunini landscape; forest succession, animal population growth, hunting of animals, and land clearing for agriculture. All of these processes are carried out by a set of computational unit, called "agents". In this program, there are four types of agents - patches, villages, households, and animals. Here, we describe the impacts of hunting on the biodiversity based on actual demographic data from one village named Crush Water. Animal population within the hunting territory of the village stabilized but Agouti/Paca dominates the landscape with little population of armadillos and peccaries. White-tailed deers

  6. Anthropogenic habitat disturbance and the dynamics of hantavirus using remote sensing, GIS, and a spatially explicit agent-based model

    Science.gov (United States)

    Cao, Lina

    Sin Nombre virus (SNV), a strain of hantavirus, causes hantavirus pulmonary syndrome (HPS) in humans, a deadly disease with high mortality rate (>50%). The primary virus host is deer mice, and greater deer mice abundance has been shown to increase the human risk of HPS. There is a great need in understanding the nature of the virus host, its temporal and spatial dynamics, and its relation to the human population with the purpose of predicting human risk of the disease. This research studies SNV dynamics in deer mice in the Great Basin Desert of central Utah, USA using multiyear field data and integrated geospatial approaches including remote sensing, Geographic Information System (GIS), and a spatially explicit agent-based model. The goal is to advance our understanding of the important ecological and demographic factors that affect the dynamics of deer mouse population and SNV prevalence. The primary research question is how climate, habitat disturbance, and deer mouse demographics affect deer mouse population density, its movement, and SNV prevalence in the sagebrush habitat. The results show that the normalized difference vegetation index (NDVI) and the enhanced vegetation index (EVI) can be good predictors of deer mouse density and the number of infected deer mice with a time lag of 1.0 to 1.3 years. This information can be very useful in predicting mouse abundance and SNV risk. The results also showed that climate, mouse density, sex, mass, and SNV infection had significant effects on deer mouse movement. The effect of habitat disturbance on mouse movement varies according to climate conditions with positive relationship in predrought condition and negative association in postdrought condition. The heavier infected deer mice moved the most. Season and disturbance alone had no significant effects. The spatial agent-based model (SABM) simulation results show that prevalence was negatively related to the disturbance levels and the sensitivity analysis showed that

  7. Comparing administered and market-based water allocation systems through a consistent agent-based modeling framework.

    Science.gov (United States)

    Zhao, Jianshi; Cai, Ximing; Wang, Zhongjing

    2013-07-15

    Water allocation can be undertaken through administered systems (AS), market-based systems (MS), or a combination of the two. The debate on the performance of the two systems has lasted for decades but still calls for attention in both research and practice. This paper compares water users' behavior under AS and MS through a consistent agent-based modeling framework for water allocation analysis that incorporates variables particular to both MS (e.g., water trade and trading prices) and AS (water use violations and penalties/subsidies). Analogous to the economic theory of water markets under MS, the theory of rational violation justifies the exchange of entitled water under AS through the use of cross-subsidies. Under water stress conditions, a unique water allocation equilibrium can be achieved by following a simple bargaining rule that does not depend upon initial market prices under MS, or initial economic incentives under AS. The modeling analysis shows that the behavior of water users (agents) depends on transaction, or administrative, costs, as well as their autonomy. Reducing transaction costs under MS or administrative costs under AS will mitigate the effect that equity constraints (originating with primary water allocation) have on the system's total net economic benefits. Moreover, hydrologic uncertainty is shown to increase market prices under MS and penalties/subsidies under AS and, in most cases, also increases transaction, or administrative, costs. PMID:23597927

  8. Examining Social Adaptations in a Volatile Landscape in Northern Mongolia via the Agent-Based Model Ger Grouper

    Directory of Open Access Journals (Sweden)

    Julia K. Clark

    2015-03-01

    Full Text Available The environment of the mountain-steppe-taiga of northern Mongolia is often characterized as marginal because of the high altitude, highly variable precipitation levels, low winter temperatures, and periodic droughts coupled with severe winter storms (known as dzuds. Despite these conditions, herders have inhabited this landscape for thousands of years, and hunter-gatherer-fishers before that. One way in which the risks associated with such a challenging and variable landscape are mitigated is through social networks and inter-family cooperation. We present an agent-based simulation, Ger Grouper, to examine how households have mitigated these risks through cooperation. The Ger Grouper simulation takes into account locational decisions of households, looks at fission/fusion dynamics of households and how those relate to environmental pressures, and assesses how degrees of relatedness can influence sharing of resources during harsh winters. This model, coupled with the traditional archaeological and ethnographic methods, helps shed light on the links between early Mongolian pastoralist adaptations and the environment. While preliminary results are promising, it is hoped that further development of this model will be able to characterize changing land-use patterns as social and political networks developed.

  9. An agent-based model driven by tropical rainfall to understand the spatio-temporal heterogeneity of a chikungunya outbreak.

    Science.gov (United States)

    Dommar, Carlos J; Lowe, Rachel; Robinson, Marguerite; Rodó, Xavier

    2014-01-01

    Vector-borne diseases, such as dengue, malaria and chikungunya, are increasing across their traditional ranges and continuing to infiltrate new, previously unaffected, regions. The spatio-temporal evolution of these diseases is determined by the interaction of the host and vector, which is strongly dependent on social structures and mobility patterns. We develop an agent-based model (ABM), in which each individual is explicitly represented and vector populations are linked to precipitation estimates in a tropical setting. The model is implemented on both scale-free and regular networks. The spatio-temporal transmission of chikungunya is analysed and the presence of asymptomatic silent spreaders within the population is investigated in the context of implementing travel restrictions during an outbreak. Preventing the movement of symptomatic individuals is found to be an insufficient mechanism to halt the spread of the disease, which can be readily carried to neighbouring nodes via sub-clinical individuals. Furthermore, the impact of topology structure vs. precipitation levels is assessed and precipitation is found to be the dominant factor driving spatio-temporal transmission. PMID:23958228

  10. Comparing administered and market-based water allocation systems through a consistent agent-based modeling framework.

    Science.gov (United States)

    Zhao, Jianshi; Cai, Ximing; Wang, Zhongjing

    2013-07-15

    Water allocation can be undertaken through administered systems (AS), market-based systems (MS), or a combination of the two. The debate on the performance of the two systems has lasted for decades but still calls for attention in both research and practice. This paper compares water users' behavior under AS and MS through a consistent agent-based modeling framework for water allocation analysis that incorporates variables particular to both MS (e.g., water trade and trading prices) and AS (water use violations and penalties/subsidies). Analogous to the economic theory of water markets under MS, the theory of rational violation justifies the exchange of entitled water under AS through the use of cross-subsidies. Under water stress conditions, a unique water allocation equilibrium can be achieved by following a simple bargaining rule that does not depend upon initial market prices under MS, or initial economic incentives under AS. The modeling analysis shows that the behavior of water users (agents) depends on transaction, or administrative, costs, as well as their autonomy. Reducing transaction costs under MS or administrative costs under AS will mitigate the effect that equity constraints (originating with primary water allocation) have on the system's total net economic benefits. Moreover, hydrologic uncertainty is shown to increase market prices under MS and penalties/subsidies under AS and, in most cases, also increases transaction, or administrative, costs.

  11. Adaptive management in crop pest control in the face of climate variability: an agent-based modeling approach

    Directory of Open Access Journals (Sweden)

    François Rebaudo

    2015-06-01

    Full Text Available Climate changes are occurring rapidly at both regional and global scales. Farmers are faced with the challenge of developing new agricultural practices to help them to cope with unpredictable changes in environmental, social, and economic conditions. Under these conditions, adaptive management requires a farmer to learn by monitoring provisional strategies and changing conditions, and then incrementally adjust management practices in light of new information. Exploring adaptive management will increase our understanding of the underlying processes that link farmer societies with their environment across space and time, while accounting for the impacts of an unpredictable climate. Here, we assessed the impacts of temperature and crop price, as surrogates for climate and economic changes, on farmers' adaptive management in crop pest control using an agent-based modeling approach. Our model simulated an artificial society of farmers that relied on field data obtained in the Ecuadorian Andes. Farmers were represented as heterogeneous autonomous agents who interact with and influence each other, and who are capable of adapting to changing environmental conditions. The results of our simulation suggest that variable temperatures led to less effective pest control strategies than those used under stable temperatures. Moreover, farmers used information gained through their own past experience or through interactions with other farmers to initiate an adaptive management approach. At a broader scale, this study generates more than an increased understanding of adaptive management; it highlights how people depend on one another to manage common problems.

  12. Modelling Temporal Schedule of Urban Trains Using Agent-Based Simulation and NSGA2-BASED Multiobjective Optimization Approaches

    Science.gov (United States)

    Sahelgozin, M.; Alimohammadi, A.

    2015-12-01

    Increasing distances between locations of residence and services leads to a large number of daily commutes in urban areas. Developing subway systems has been taken into consideration of transportation managers as a response to this huge amount of travel demands. In developments of subway infrastructures, representing a temporal schedule for trains is an important task; because an appropriately designed timetable decreases Total passenger travel times, Total Operation Costs and Energy Consumption of trains. Since these variables are not positively correlated, subway scheduling is considered as a multi-criteria optimization problem. Therefore, proposing a proper solution for subway scheduling has been always a controversial issue. On the other hand, research on a phenomenon requires a summarized representation of the real world that is known as Model. In this study, it is attempted to model temporal schedule of urban trains that can be applied in Multi-Criteria Subway Schedule Optimization (MCSSO) problems. At first, a conceptual framework is represented for MCSSO. Then, an agent-based simulation environment is implemented to perform Sensitivity Analysis (SA) that is used to extract the interrelations between the framework components. These interrelations is then taken into account in order to construct the proposed model. In order to evaluate performance of the model in MCSSO problems, Tehran subway line no. 1 is considered as the case study. Results of the study show that the model was able to generate an acceptable distribution of Pareto-optimal solutions which are applicable in the real situations while solving a MCSSO is the goal. Also, the accuracy of the model in representing the operation of subway systems was significant.

  13. MODELLING TEMPORAL SCHEDULE OF URBAN TRAINS USING AGENT-BASED SIMULATION AND NSGA2-BASED MULTIOBJECTIVE OPTIMIZATION APPROACHES

    Directory of Open Access Journals (Sweden)

    M. Sahelgozin

    2015-12-01

    Full Text Available Increasing distances between locations of residence and services leads to a large number of daily commutes in urban areas. Developing subway systems has been taken into consideration of transportation managers as a response to this huge amount of travel demands. In developments of subway infrastructures, representing a temporal schedule for trains is an important task; because an appropriately designed timetable decreases Total passenger travel times, Total Operation Costs and Energy Consumption of trains. Since these variables are not positively correlated, subway scheduling is considered as a multi-criteria optimization problem. Therefore, proposing a proper solution for subway scheduling has been always a controversial issue. On the other hand, research on a phenomenon requires a summarized representation of the real world that is known as Model. In this study, it is attempted to model temporal schedule of urban trains that can be applied in Multi-Criteria Subway Schedule Optimization (MCSSO problems. At first, a conceptual framework is represented for MCSSO. Then, an agent-based simulation environment is implemented to perform Sensitivity Analysis (SA that is used to extract the interrelations between the framework components. These interrelations is then taken into account in order to construct the proposed model. In order to evaluate performance of the model in MCSSO problems, Tehran subway line no. 1 is considered as the case study. Results of the study show that the model was able to generate an acceptable distribution of Pareto-optimal solutions which are applicable in the real situations while solving a MCSSO is the goal. Also, the accuracy of the model in representing the operation of subway systems was significant.

  14. Assortative mating and the reversal of gender inequality in education in europe: an agent-based model.

    Directory of Open Access Journals (Sweden)

    André Grow

    Full Text Available While men have always received more education than women in the past, this gender imbalance in education has turned around in large parts of the world. In many countries, women now excel men in terms of participation and success in higher education. This implies that, for the first time in history, there are more highly educated women than men reaching the reproductive ages and looking for a partner. We develop an agent-based computational model that explicates the mechanisms that may have linked the reversal of gender inequality in education with observed changes in educational assortative mating. Our model builds on the notion that individuals search for spouses in a marriage market and evaluate potential candidates based on preferences. Based on insights from earlier research, we assume that men and women prefer partners with similar educational attainment and high earnings prospects, that women tend to prefer men who are somewhat older than themselves, and that men prefer women who are in their mid-twenties. We also incorporate the insight that the educational system structures meeting opportunities on the marriage market. We assess the explanatory power of our model with systematic computational experiments, in which we simulate marriage market dynamics in 12 European countries among individuals born between 1921 and 2012. In these experiments, we make use of realistic agent populations in terms of educational attainment and earnings prospects and validate model outcomes with data from the European Social Survey. We demonstrate that the observed changes in educational assortative mating can be explained without any change in male or female preferences. We argue that our model provides a useful computational laboratory to explore and quantify the implications of scenarios for the future.

  15. Modeling the Internet of Things, Self-Organizing and Other Complex Adaptive Communication Networks: A Cognitive Agent-Based Computing Approach.

    Directory of Open Access Journals (Sweden)

    Samreen Laghari

    Full Text Available Computer Networks have a tendency to grow at an unprecedented scale. Modern networks involve not only computers but also a wide variety of other interconnected devices ranging from mobile phones to other household items fitted with sensors. This vision of the "Internet of Things" (IoT implies an inherent difficulty in modeling problems.It is practically impossible to implement and test all scenarios for large-scale and complex adaptive communication networks as part of Complex Adaptive Communication Networks and Environments (CACOONS. The goal of this study is to explore the use of Agent-based Modeling as part of the Cognitive Agent-based Computing (CABC framework to model a Complex communication network problem.We use Exploratory Agent-based Modeling (EABM, as part of the CABC framework, to develop an autonomous multi-agent architecture for managing carbon footprint in a corporate network. To evaluate the application of complexity in practical scenarios, we have also introduced a company-defined computer usage policy.The conducted experiments demonstrated two important results: Primarily CABC-based modeling approach such as using Agent-based Modeling can be an effective approach to modeling complex problems in the domain of IoT. Secondly, the specific problem of managing the Carbon footprint can be solved using a multiagent system approach.

  16. “Space, the Final Frontier”: How Good are Agent-Based Models at Simulating Individuals and Space in Cities?

    Directory of Open Access Journals (Sweden)

    Alison Heppenstall

    2016-01-01

    Full Text Available Cities are complex systems, comprising of many interacting parts. How we simulate and understand causality in urban systems is continually evolving. Over the last decade the agent-based modeling (ABM paradigm has provided a new lens for understanding the effects of interactions of individuals and how through such interactions macro structures emerge, both in the social and physical environment of cities. However, such a paradigm has been hindered due to computational power and a lack of large fine scale datasets. Within the last few years we have witnessed a massive increase in computational processing power and storage, combined with the onset of Big Data. Today geographers find themselves in a data rich era. We now have access to a variety of data sources (e.g., social media, mobile phone data, etc. that tells us how, and when, individuals are using urban spaces. These data raise several questions: can we effectively use them to understand and model cities as complex entities? How well have ABM approaches lent themselves to simulating the dynamics of urban processes? What has been, or will be, the influence of Big Data on increasing our ability to understand and simulate cities? What is the appropriate level of spatial analysis and time frame to model urban phenomena? Within this paper we discuss these questions using several examples of ABM applied to urban geography to begin a dialogue about the utility of ABM for urban modeling. The arguments that the paper raises are applicable across the wider research environment where researchers are considering using this approach.

  17. Leveraging social influence to address overweight and obesity using agent-based models: the role of adolescent social networks.

    Science.gov (United States)

    Zhang, J; Tong, L; Lamberson, P J; Durazo-Arvizu, R A; Luke, A; Shoham, D A

    2015-01-01

    The prevalence of adolescent overweight and obesity (hereafter, simply "overweight") in the US has increased over the past several decades. Individually-targeted prevention and treatment strategies targeting individuals have been disappointing, leading some to propose leveraging social networks to improve interventions. We hypothesized that social network dynamics (social marginalization; homophily on body mass index, BMI) and the strength of peer influence would increase or decrease the proportion of network member (agents) becoming overweight over a simulated year, and that peer influence would operate differently in social networks with greater overweight. We built an agent-based model (ABM) using results from R-SIENA. ABMs allow for the exploration of potential interventions using simulated agents. Initial model specifications were drawn from Wave 1 of the National Longitudinal Study of Adolescent Health (Add Health). We focused on a single saturation school with complete network and BMI data over two waves (n = 624). The model was validated against empirical observations at Wave 2. We focused on overall overweight prevalence after a simulated year. Five experiments were conducted: (1) changing attractiveness of high-BMI agents; (2) changing homophily on BMI; (3) changing the strength of peer influence; (4) shifting the overall BMI distribution; and (5) targeting dietary interventions to highly connected individuals. Increasing peer influence showed a dramatic decrease in the prevalence of overweight; making peer influence negative (i.e., doing the opposite of friends) increased overweight. However, the effect of peer influence varied based on the underlying distribution of BMI; when BMI was increased overall, stronger peer influence increased proportion of overweight. Other interventions, including targeted dieting, had little impact. Peer influence may be a viable target in overweight interventions, but the distribution of body size in the population needs to

  18. Biodiversity in rubber agroforests, carbon emissions, and rural livelihoods: An agent-based model of land-use dynamics in lowland Sumatra

    NARCIS (Netherlands)

    Villamor, G.B.; Le, Q.B.; Djanibekov, U.; Noordwijk, van M.; Vlek, P.L.G.

    2014-01-01

    Rubber agroforests in the mostly deforested lowlands of Sumatra, Indonesia are threatened by conversion into monoculture rubber or oil palm plantations. We applied an agent-based model to explore the potential effectiveness of a payment for ecosystem services (PES) design through a biodiversity rich

  19. Understanding the Mechanisms of Collective Decision Making in Ecological Restoration: An Agent-Based Model of Actors and Organizations

    Directory of Open Access Journals (Sweden)

    Cristy Watkins

    2013-06-01

    Full Text Available Ecological restoration, particularly in urban contexts, is a complex collective decision-making process that involves a diversity of stakeholders and experts, each with their own perceptions and preferences about what landscapes should and can look like, how to get them to the desired state, and on what timeline. We investigate how structural and behavioral factors may influence collective decision making in the context of ecological restoration, with the purpose of establishing general relationships between management styles (defined by structural and behavioral factors of the organization and decision outcomes. Informed by existing literature on collective decision making and by empirical data from the Chicago Wilderness region, we present a stylized agent-based model that maps out and simulates the processes by which individuals within restoration organizations communicate, discuss, and ultimately make a decision. Our study examines how structural and behavioral characteristics--including: (a the number of actors and groups involved in decision making, (b the frequency and type of interactions among actors, (c the initial setup of positions and respect, (d outside information, and (e entrenchment and cost of dissent--lead to or prohibit group convergence in terms of collective position, variation in position across actors, and final decision strategies. We found that formal meetings and group leaders are important facilitators of convergence, especially when multiple groups are present, new information is introduced in the process, and participants are polarized around an issue. Also, intergroup interactions are particularly important for overall convergence. Position entrenchment slows the convergence process and increases the need for decision strategies involving outside intervention. Cost of dissent can reinforce these effects. Our study formalizes collective decision-making processes within the context of ecological restoration

  20. Irrigated Agriculture in Morocco: An Agent-Based Model of Adaptation and Decision Making Amid Increasingly Frequent Drought Events

    Science.gov (United States)

    Norton, M.

    2015-12-01

    In the past 100 years, Morocco has undertaken a heavy investment in developing water infrastructure that has led to a dramatic expansion of irrigated agriculture. Irrigated agriculture is the primary user of water in many arid countries, often accounting for 80-90% of total water usage. Irrigation is adopted by farmers not only because it leads to increased production, but also because it improves resilience to an uncertain climate. However, the Mediterranean region as a whole has also seen an increase in the frequency and severity of drought events. These droughts have had a dramatic impact on farmer livelihoods and have led to a number of coping strategies, including the adoption or disadoption of irrigation. In this study, we use a record of the annual extent of irrigated agriculture in Morocco to model the effect of drought on the extent of irrigated agriculture. Using an agent-based socioeconomic model, we seek to answer the following questions: 1) Do farmers expand irrigated agriculture in response to droughts? 2) Do drought events entail the removal of perennial crops like orchards? 3) Can we detect the retreat of irrigated agriculture in the more fragile watersheds of Morocco? Understanding the determinants of irrigated crop expansion and contractions will help us understand how agro-ecological systems transition from 20th century paradigms of expansion of water supply to a 21st century paradigm of water use efficiency. The answers will become important as countries learn how to manage water in new climate regimes characterized by less reliable and available precipitation.

  1. Modelling and simulation of electrical energy systems through a complex systems approach using agent-based models. Case study: Under-frequency load shedding for refrigerators

    Energy Technology Data Exchange (ETDEWEB)

    Kremers, Enrique [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany). European Inst. for Energy Research (EIFER); Gonzalez de Durana, Jose Maria; Barambones, Oscar [Universidad del Pais Vasco, Vitoria (Spain). Escuela Universitaria de Ingenieria de Vitoria-Gasteiz

    2013-09-01

    One of the ways of studying complex systems is through modelling and simulation, which are used as tools to represent these systems in a virtual environment. Current advances in computing performance (which has been a major constraint in this field for some time) allow for the simulation these kinds of systems within reasonable time horizons. One of the tools for simulating complex systems is agent-based modelling. This individual-centric approach is based on autonomous entities that can interact with each other, thus modelling the system in a disaggregated way. Agent-based models can be coupled with other modelling methods, such as continuous models and discrete events, which can be embedded or run in parallel to the multi-agent system. When representing the electrical energy system in a systemic and multi-layered way, it is treated as a true socio-technical system, in which not only technical models are taken into account, but also socio-behavioural ones. In this work, a number of different models for the parts of an electrical system are presented, related to production, demand and storage. The models are intended to be as simple as possible in order to be simulated in an integrated framework representing the system as a whole. Furthermore, the models allow the inclusion of social behaviour and other, not purely engineering-related aspects of the system, which have to be considered from a complex point of view. (orig.)

  2. Applying an agent-based model of agricultural terraces coupled with a landscape evolution model to explore the impact of human decision-making on terraced terrain

    Science.gov (United States)

    Glaubius, Jennifer

    2016-04-01

    Agricultural terraces impact landscape evolution as a result of long-term human-landscape interactions, including decisions regarding terrace maintenance and abandonment. Modeling simulations are often employed to examine the sensitivity of landscapes to various factors, such as rainfall and land cover. Landscape evolution models, erosion models, and hydrological models have all previously been used to simulate the impact of agricultural terrace construction on terrain evolution, soil erosion, and hydrological connectivity. Human choices regarding individual terraces have not been included in these models to this point, despite recent recognition that maintenance and abandonment decisions alter transport and storage patterns of soil and water in terraced terrain. An agent-based model of human decisions related to agricultural terraces is implemented based on a conceptual model of agricultural terrace life cycle stages created from a literature review of terracing impacts. The agricultural terracing agent-based model is then coupled with a landscape evolution model to explore the role of human decisions in the evolution of terraced landscapes. To fully explore this type of co-evolved landscape, human decision-making and its feedbacks must be included in landscape evolution models. Project results may also have implications for management of terraced terrain based on how human choices in these environments affect soil loss and land degradation.

  3. Reducing Moose–Vehicle Collisions through Salt Pool Removal and Displacement: an Agent-Based Modeling Approach

    Directory of Open Access Journals (Sweden)

    Christian Dussault

    2009-12-01

    Full Text Available Between 1990 and 2002, more than 200 moose–vehicle collisions occurred each year in Quebec, including about 50/yr in the Laurentides Wildlife Reserve. One cause is the presence of roadside salt pools that attract moose near roads in the spring and summer. Using the computer simulation technique of agent-based modeling, this study investigated whether salt pool removal and displacement, i.e., a compensatory salt pool set up 100 to 1500 m away from the road shoulder, would reduce the number of moose–vehicle collisions. Moose road crossings were used as a proxy measure. A GPS telemetry data set consisting of approximately 200,000 locations of 47 moose over 2 yr in the Laurentides Wildlife Reserve was used as an empirical basis for the model. Twelve moose were selected from this data set and programmed in the model to forage and travel in the study area. Five parameters with an additional application of stochasticity were used to determine moose movement between forest polygons. These included food quality; cover quality, i.e., protection from predators and thermal stress; proximity to salt pools; proximity to water; and slope. There was a significant reduction in road crossings when either all or two thirds of the roadside salt pools were removed, with and/or without salt pool displacement. With 100% salt pool removal, the reduction was greater (49% without compensatory salt pools than with them (18%. When two thirds of the salt pools were removed, the reduction was the same with and without compensatory salt pools (16%. Although moose–vehicle collisions are not a significant mortality factor for the moose population in the Laurentides Wildlife Reserve, in areas with higher road densities, hunting pressure, and/or predator densities it could mean the difference between a stable and a declining population, and salt pool removal could be part of a good mitigation plan to halt population declines. This model can be used, with improvements such

  4. Modelling skylarks (Alauda arvensis) to predict impacts of changes in land management and policy: development and testing of an agent-based model

    DEFF Research Database (Denmark)

    Topping, Christopher John; Odderskær, Peter; Kahlert, Johnny Abildgaard

    2013-01-01

    formal description inter-linked to the program code). Detailed and stringent tests for model performance were carried out, and standardised model description and open access to the source code were provided to open development of the skylark model to others. Over and above documenting the utility......Agent-based simulation models provide a viable approach for developing applied models of species and systems for predictive management. However, there has been some reluctance to use these models for policy applications due to complexity and the need for improved testing and communication...... of the models. We present the development and testing of a comprehensive model for Skylark (Alauda arvensis) in Danish agricultural landscapes. The model is part of the ALMaSS system, which considers not only individual skylarks, but also the detailed dynamic environment from which they obtain the information...

  5. An Agent-Based Model of a Hepatic Inflammatory Response to Salmonella: A Computational Study under a Large Set of Experimental Data.

    Science.gov (United States)

    Shi, Zhenzhen; Chapes, Stephen K; Ben-Arieh, David; Wu, Chih-Hang

    2016-01-01

    We present an agent-based model (ABM) to simulate a hepatic inflammatory response (HIR) in a mouse infected by Salmonella that sometimes progressed to problematic proportions, known as "sepsis". Based on over 200 published studies, this ABM describes interactions among 21 cells or cytokines and incorporates 226 experimental data sets and/or data estimates from those reports to simulate a mouse HIR in silico. Our simulated results reproduced dynamic patterns of HIR reported in the literature. As shown in vivo, our model also demonstrated that sepsis was highly related to the initial Salmonella dose and the presence of components of the adaptive immune system. We determined that high mobility group box-1, C-reactive protein, and the interleukin-10: tumor necrosis factor-α ratio, and CD4+ T cell: CD8+ T cell ratio, all recognized as biomarkers during HIR, significantly correlated with outcomes of HIR. During therapy-directed silico simulations, our results demonstrated that anti-agent intervention impacted the survival rates of septic individuals in a time-dependent manner. By specifying the infected species, source of infection, and site of infection, this ABM enabled us to reproduce the kinetics of several essential indicators during a HIR, observe distinct dynamic patterns that are manifested during HIR, and allowed us to test proposed therapy-directed treatments. Although limitation still exists, this ABM is a step forward because it links underlying biological processes to computational simulation and was validated through a series of comparisons between the simulated results and experimental studies. PMID:27556404

  6. An Agent-Based Model of a Hepatic Inflammatory Response to Salmonella: A Computational Study under a Large Set of Experimental Data

    Science.gov (United States)

    Chapes, Stephen K.; Ben-Arieh, David; Wu, Chih-Hang

    2016-01-01

    We present an agent-based model (ABM) to simulate a hepatic inflammatory response (HIR) in a mouse infected by Salmonella that sometimes progressed to problematic proportions, known as “sepsis”. Based on over 200 published studies, this ABM describes interactions among 21 cells or cytokines and incorporates 226 experimental data sets and/or data estimates from those reports to simulate a mouse HIR in silico. Our simulated results reproduced dynamic patterns of HIR reported in the literature. As shown in vivo, our model also demonstrated that sepsis was highly related to the initial Salmonella dose and the presence of components of the adaptive immune system. We determined that high mobility group box-1, C-reactive protein, and the interleukin-10: tumor necrosis factor-α ratio, and CD4+ T cell: CD8+ T cell ratio, all recognized as biomarkers during HIR, significantly correlated with outcomes of HIR. During therapy-directed silico simulations, our results demonstrated that anti-agent intervention impacted the survival rates of septic individuals in a time-dependent manner. By specifying the infected species, source of infection, and site of infection, this ABM enabled us to reproduce the kinetics of several essential indicators during a HIR, observe distinct dynamic patterns that are manifested during HIR, and allowed us to test proposed therapy-directed treatments. Although limitation still exists, this ABM is a step forward because it links underlying biological processes to computational simulation and was validated through a series of comparisons between the simulated results and experimental studies. PMID:27556404

  7. A methodology for eliciting, representing, and analysing stakeholder knowledge for decision making on complex socio-ecological systems: from cognitive maps to agent-based models.

    Science.gov (United States)

    Elsawah, Sondoss; Guillaume, Joseph H A; Filatova, Tatiana; Rook, Josefine; Jakeman, Anthony J

    2015-03-15

    This paper aims to contribute to developing better ways for incorporating essential human elements in decision making processes for modelling of complex socio-ecological systems. It presents a step-wise methodology for integrating perceptions of stakeholders (qualitative) into formal simulation models (quantitative) with the ultimate goal of improving understanding and communication about decision making in complex socio-ecological systems. The methodology integrates cognitive mapping and agent based modelling. It cascades through a sequence of qualitative/soft and numerical methods comprising: (1) Interviews to elicit mental models; (2) Cognitive maps to represent and analyse individual and group mental models; (3) Time-sequence diagrams to chronologically structure the decision making process; (4) All-encompassing conceptual model of decision making, and (5) computational (in this case agent-based) Model. We apply the proposed methodology (labelled ICTAM) in a case study of viticulture irrigation in South Australia. Finally, we use strengths-weakness-opportunities-threats (SWOT) analysis to reflect on the methodology. Results show that the methodology leverages the use of cognitive mapping to capture the richness of decision making and mental models, and provides a combination of divergent and convergent analysis methods leading to the construction of an Agent Based Model.

  8. A methodology for eliciting, representing, and analysing stakeholder knowledge for decision making on complex socio-ecological systems: from cognitive maps to agent-based models.

    Science.gov (United States)

    Elsawah, Sondoss; Guillaume, Joseph H A; Filatova, Tatiana; Rook, Josefine; Jakeman, Anthony J

    2015-03-15

    This paper aims to contribute to developing better ways for incorporating essential human elements in decision making processes for modelling of complex socio-ecological systems. It presents a step-wise methodology for integrating perceptions of stakeholders (qualitative) into formal simulation models (quantitative) with the ultimate goal of improving understanding and communication about decision making in complex socio-ecological systems. The methodology integrates cognitive mapping and agent based modelling. It cascades through a sequence of qualitative/soft and numerical methods comprising: (1) Interviews to elicit mental models; (2) Cognitive maps to represent and analyse individual and group mental models; (3) Time-sequence diagrams to chronologically structure the decision making process; (4) All-encompassing conceptual model of decision making, and (5) computational (in this case agent-based) Model. We apply the proposed methodology (labelled ICTAM) in a case study of viticulture irrigation in South Australia. Finally, we use strengths-weakness-opportunities-threats (SWOT) analysis to reflect on the methodology. Results show that the methodology leverages the use of cognitive mapping to capture the richness of decision making and mental models, and provides a combination of divergent and convergent analysis methods leading to the construction of an Agent Based Model. PMID:25622296

  9. The Tragedy of the Park: an Agent-based Model of Endogenous and Exogenous Institutions for Forest Management

    Directory of Open Access Journals (Sweden)

    Elena Vallino

    2014-03-01

    Full Text Available Many scholars of common-pool resources have found that institutions might solve the tragedy of the commons. I address a particular situation of natural resource management: that of a protected area. In this situation, interests differ. Local rural inhabitants care about the quality of their environment but also need to exploit the resources for livelihood reasons. An external entity such as the State, a donor, an NGO, or some combination thereof decides that there is a need for nature conservation in that area. Because of some evidence of failure for a strictly top-down conservationist approach, the external entity decides to apply the concept of participatory conservation: the local inhabitants become stakeholders in the management of the area and become collectively responsible for conservation, with rights to exploit the resources up to some degree. I argue that project designers try to find a solution to nature conservation through the creation of a situation of a commons: creating a community that has rights and duties toward a particular natural area that is endowed with some resources. Many scholars rely mostly on institutions that are endogenously created within the users' community to avoid the tragedy of the commons. However, what happens if institutions are imposed? In participatory conservation initiatives, the community has collective rights over the resources, and in this sense, the issue of endogenous rules for the commons management is relevant. However, the level to which the community should exploit the resource is usually imposed by the external project designers. Using agent-based simulations, I develop a theoretical model to look at the consequences of an imposed institution on the state of a forest and on the users' profit, taking into account the possibilities of violating the imposed rules and facing enforcement. I compare the consequences of this imposed institution with those deriving from an endogenously created

  10. Evaluating the effect of human activity patterns on air pollution exposure using an integrated field-based and agent-based modelling framework

    Science.gov (United States)

    Schmitz, Oliver; Beelen, Rob M. J.; de Bakker, Merijn P.; Karssenberg, Derek

    2015-04-01

    Constructing spatio-temporal numerical models to support risk assessment, such as assessing the exposure of humans to air pollution, often requires the integration of field-based and agent-based modelling approaches. Continuous environmental variables such as air pollution are best represented using the field-based approach which considers phenomena as continuous fields having attribute values at all locations. When calculating human exposure to such pollutants it is, however, preferable to consider the population as a set of individuals each with a particular activity pattern. This would allow to account for the spatio-temporal variation in a pollutant along the space-time paths travelled by individuals, determined, for example, by home and work locations, road network, and travel times. Modelling this activity pattern requires an agent-based or individual based modelling approach. In general, field- and agent-based models are constructed with the help of separate software tools, while both approaches should play together in an interacting way and preferably should be combined into one modelling framework, which would allow for efficient and effective implementation of models by domain specialists. To overcome this lack in integrated modelling frameworks, we aim at the development of concepts and software for an integrated field-based and agent-based modelling framework. Concepts merging field- and agent-based modelling were implemented by extending PCRaster (http://www.pcraster.eu), a field-based modelling library implemented in C++, with components for 1) representation of discrete, mobile, agents, 2) spatial networks and algorithms by integrating the NetworkX library (http://networkx.github.io), allowing therefore to calculate e.g. shortest routes or total transport costs between locations, and 3) functions for field-network interactions, allowing to assign field-based attribute values to networks (i.e. as edge weights), such as aggregated or averaged

  11. An integrated modeling framework of socio-economic, biophysical, and hydrological processes in Midwest landscapes: Remote sensing data, agro-hydrological model, and agent-based model

    Science.gov (United States)

    Ding, Deng

    Intensive human-environment interactions are taking place in Midwestern agricultural systems. An integrated modeling framework is suitable for predicting dynamics of key variables of the socio-economic, biophysical, hydrological processes as well as exploring the potential transitions of system states in response to changes of the driving factors. The purpose of this dissertation is to address issues concerning the interacting processes and consequent changes in land use, water balance, and water quality using an integrated modeling framework. This dissertation is composed of three studies in the same agricultural watershed, the Clear Creek watershed in East-Central Iowa. In the first study, a parsimonious hydrologic model, the Threshold-Exceedance-Lagrangian Model (TELM), is further developed into RS-TELM (Remote Sensing TELM) to integrate remote sensing vegetation data for estimating evapotranspiration. The goodness of fit of RS-TELM is comparable to a well-calibrated SWAT (Soil and Water Assessment Tool) and even slightly superior in capturing intra-seasonal variability of stream flow. The integration of RS LAI (Leaf Area Index) data improves the model's performance especially over the agriculture dominated landscapes. The input of rainfall datasets with spatially explicit information plays a critical role in increasing the model's goodness of fit. In the second study, an agent-based model is developed to simulate farmers' decisions on crop type and fertilizer application in response to commodity and biofuel crop prices. The comparison between simulated crop land percentage and crop rotations with satellite-based land cover data suggest that farmers may be underestimating the effects that continuous corn production has on yields (yield drag). The simulation results given alternative market scenarios based on a survey of agricultural land owners and operators in the Clear Creek Watershed show that, farmers see cellulosic biofuel feedstock production in the form

  12. Modeling tumor evolutionary dynamics

    Directory of Open Access Journals (Sweden)

    Beatriz eStransky

    2013-02-01

    Full Text Available Tumorigenesis can be seen as an evolutionary process, in which the transformation of a normal cell into a tumor cell involves a number of limiting genetic and epigenetic events, occurring in a series of discrete stages. However, not all mutations in a cell are directly involved in cancer development and it is likely that most of them (passenger mutations do not contribute in any way to tumorigenesis. Moreover, the process of tumor evolution is punctuated by selection of advantageous (driver mutations and clonal expansions. Regarding these driver mutations, it is uncertain how many limiting events are required and / or sufficient to promote a tumorigenic process or what are the values associated with the adaptive advantage of different driver mutations. In spite of the availability of high-quality cancer data, several assumptions about the mechanistic process of cancer initiation and development remain largely untested, both mathematically and statistically. Here we review the development of mathematical/computational models where some assumptions were tested and discuss the impact of these models to the field of tumor biology.

  13. 基于agent-based model的住房市场演化问题研究%Research on the housing market evolution based on agent-based model

    Institute of Scientific and Technical Information of China (English)

    邓琳; 闫妍; 朱晓武; 李晓腾

    2015-01-01

    在房地产市场中,多个具有一定量财富的个体依据其不同需求产生具有差异性的住房选择行为,在宏观上会呈现某些特定的规律.本文从这一角度出发,运用agent-based model,在居民家庭财富增长和房屋价格双重因素的考虑下,依据房地产市场中个体的实际行为规律,设定出相应的运行规则,对房地产市场中个体迁移图景进行了计算机模拟.以基尼系数作为衡量经济不平等程度的标准,空间差异指数作为经济分割的度量指标,改变模型初始条件和各参数取值,从多角度分析,最终得出,在现有住房规律之下,随着居民家庭财富的不断增长,会导致城市居民出现居住空间上的隔离并进一步拉大贫富差距,形成空间经济分割的现象.

  14. Results and Lessons Learned from a Coupled Social and Physical Hydrology Model: Testing Alternative Water Management Policies and Institutional Structures Using Agent-Based Modeling and Regional Hydrology

    Science.gov (United States)

    Murphy, J.; Lammers, R. B.; Prousevitch, A.; Ozik, J.; Altaweel, M.; Collier, N. T.; Kliskey, A. D.; Alessa, L.

    2015-12-01

    Water Management in the U.S. Southwest is under increasing scrutiny as many areas endure persistent drought. The impact of these prolonged dry conditions is a product of regional climate and hydrological conditions, but also of a highly engineered water management infrastructure and a complex web of social arrangements whereby water is allocated, shared, exchanged, used, re-used, and finally consumed. We coupled an agent-based model with a regional hydrological model to understand the dynamics in one richly studied and highly populous area: southern Arizona, U.S.A., including metropolitan Phoenix and Tucson. There, multiple management entities representing an array of municipalities and other water providers and customers, including private companies and Native American tribes are enmeshed in a complex legal and economic context in which water is bought, leased, banked, and exchanged in a variety of ways and on multiple temporal and physical scales. A recurrent question in the literature of adaptive management is the impact of management structure on overall system performance. To explore this, we constructed an agent-based model to capture this social complexity, and coupled this with a physical hydrological model that we used to drive the system under a variety of water stress scenarios and to assess the regional impact of the social system's performance. We report the outcomes of ensembles of runs in which varieties of alternative policy constraints and management strategies are considered. We hope to contribute to policy discussions in this area and connected and legislatively similar areas (such as California) as current conditions change and existing legal and policy structures are revised. Additionally, we comment on the challenges of integrating models that ostensibly are in different domains (physical and social) but that independently represent a system in which physical processes and human actions are closely intertwined and difficult to disentangle.

  15. An Agent-Based Model of Endogenous Technological Change -- An Extension to the Grubler-Gritsevskyi Model

    OpenAIRE

    T. Ma

    2006-01-01

    Based on earlier, pioneering work done at IIASA, this paper presents a model of endogenous technological change under the three potential most important "stylized facts": increasing returns to adoption, uncertainty, and heterogeneous agents following diverse technology development and adoption strategies. As an intermediary step towards the final, long-term research objective of developing a multi-agent model, this paper deals with two heterogeneous agents, a risk-taking one and a risk-aversi...

  16. Integrating the simulation of domestic water demand behaviour to an urban water model using agent based modelling

    Science.gov (United States)

    Koutiva, Ifigeneia; Makropoulos, Christos

    2015-04-01

    The urban water system's sustainable evolution requires tools that can analyse and simulate the complete cycle including both physical and cultural environments. One of the main challenges, in this regard, is the design and development of tools that are able to simulate the society's water demand behaviour and the way policy measures affect it. The effects of these policy measures are a function of personal opinions that subsequently lead to the formation of people's attitudes. These attitudes will eventually form behaviours. This work presents the design of an ABM tool for addressing the social dimension of the urban water system. The created tool, called Urban Water Agents' Behaviour (UWAB) model, was implemented, using the NetLogo agent programming language. The main aim of the UWAB model is to capture the effects of policies and environmental pressures to water conservation behaviour of urban households. The model consists of agents representing urban households that are linked to each other creating a social network that influences the water conservation behaviour of its members. Household agents are influenced as well by policies and environmental pressures, such as drought. The UWAB model simulates behaviour resulting in the evolution of water conservation within an urban population. The final outcome of the model is the evolution of the distribution of different conservation levels (no, low, high) to the selected urban population. In addition, UWAB is implemented in combination with an existing urban water management simulation tool, the Urban Water Optioneering Tool (UWOT) in order to create a modelling platform aiming to facilitate an adaptive approach of water resources management. For the purposes of this proposed modelling platform, UWOT is used in a twofold manner: (1) to simulate domestic water demand evolution and (2) to simulate the response of the water system to the domestic water demand evolution. The main advantage of the UWAB - UWOT model

  17. Modelling Skylarks (Alauda arvensis to predict impacts of changes in land management and policy: development and testing of an agent-based model.

    Directory of Open Access Journals (Sweden)

    Christopher J Topping

    Full Text Available Agent-based simulation models provide a viable approach for developing applied models of species and systems for predictive management. However, there has been some reluctance to use these models for policy applications due to complexity and the need for improved testing and communication of the models. We present the development and testing of a comprehensive model for Skylark (Alauda arvensis in Danish agricultural landscapes. The model is part of the ALMaSS system, which considers not only individual skylarks, but also the detailed dynamic environment from which they obtain the information necessary to simulate their behaviour. Population responses emerge from individuals interacting with each other and the environment. Model development and testing was carried out using pattern-oriented modelling. The testing procedure was based on the model's ability to represent detailed real world patterns of distribution and density, reproductive performance and seasonal changes in territory numbers. Data to support this was collected over a 13-year period and comprised detailed field observations of breeding birds and intensive surveys. The model was able to recreate the real world data patterns accurately; it was also able to simultaneously fit a number of other secondary system properties which were not formally a part of the testing procedure. The correspondence of model output to real world data and sensitivity analysis are presented and discussed, and the model's description is provided in ODdox format (a formal description inter-linked to the program code. Detailed and stringent tests for model performance were carried out, and standardised model description and open access to the source code were provided to open development of the skylark model to others. Over and above documenting the utility of the model, this open process is essential to engender the user trust and ensure continued development of these comprehensive systems for applied

  18. Levels of Organisation in agent-based modelling for renewable resources management. Agricultural water management collective rules enforcement in the French Drome River Valley Case Study

    International Nuclear Information System (INIS)

    Levels of Organisation in agent-based modelling for renewable resources management. Agricultural water management collective rules enforcement in the French Dr me River Valley Case Study. In the context of Agent-Based Modelling for participative renewable resources management, this thesis is concerned with representing multiple tangled levels of organisation of a system. The Agent-Group-Role (AGR) formalism is borrowed from computer science research. It has been conceptually specified to handle levels of organisation, and behaviours within levels of organisation. A design methodology dedicated to AGR modelling has been developed, together with an implementation of the formalism over a multi-agent platform. AGR models of agricultural water management in the French Dr me River Valley have been built and tested. This experiment demonstrates the AGR formalism ability to (1) clarify usually implicit hypothesis on action modes, scales or viewpoints (2) facilitate the definition of scenarios with various collective rules, and various rules in enforcement behaviours (3) generate bricks for generic irrigated catchment models. (author)

  19. Job placement agencies in an agent-based model of the local labor market with the long-term unemployed and on-the-job flows

    OpenAIRE

    Wozniak, Marcin

    2016-01-01

    In this paper, an agent-based search model of the labor market with heterogeneous agents and an on-the-job search is developed, i.e. the long-term unemployed and other job seekers compete for vacancies which differ in skills demands and in the sector of the economy. Job placement agencies help both types of unemployed persons find the proper vacant job by improving their search effectiveness and by sharing leveraged job advertisements. The agents' interactions take place in an artificial worl...

  20. Will domestic consumers take up the renewable heat incentive? An analysis of the barriers to heat pump adoption using agent-based modelling

    International Nuclear Information System (INIS)

    The UK Government introduced the tariff-based domestic Renewable Heat Incentive (RHI) in April 2014 to encourage installation of renewable heat technologies as a key component of its carbon reduction policy. Of these, heat pumps are considered to be the most promising for widespread adoption and as such are the subject of this paper. Pilot studies prior to introduction of the policy identified non-financial barriers to uptake, such as the “hassle factor” involved, and initial figures indeed indicate that uptake is lower than expected. We analyse these non-financial barriers using an agent-based model and conclude that there is a tipping point beyond which adoption is likely to fall very sharply. We suggest that the RHI’s complex and stringent compliance requirements for home inspections and heat emitter performance may well have driven adoption past this point and that further intervention may be required if the key aims of the RHI are to be achieved. -- Highlights: •We examine the uptake of the UK Renewable Heat Incentive (RHI). •We use Agent-based modelling to simulate uptake in a heterogeneous population. •Simulation modelling suggests that uptake is sensitive to non-financial barriers. •Non-financial barriers were introduced after RHI policy impact assessment. •New barriers combined with sensitivity could explain observed lower than expected uptake

  1. How much do incentives affect car purchase? Agent-based microsimulation of consumer choice of new cars. Part 1. Model structure, simulation of bounded rationality, and model validation

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Michel G.; Haan, Peter de [ETH Zurich, Institute for Environmental Decisions, Natural and Social Science Interface, Universitaetstr. 22, CHN J 73.2, 8092 Zurich (Switzerland)

    2009-03-15

    This article presents an agent-based microsimulation capable of forecasting the effects of policy levers that influence individual choices of new passenger cars. The fundamental decision-making units are households distinguished by sociodemographic characteristics and car ownership. A two-stage model of individual decision processes is employed. In the first stage, individual choice sets are constructed using simple, non-compensatory rules that are based on previously owned cars. Second, decision makers evaluate alternatives in their individual choice set using a multi-attributive weighting rule. The attribute weights are based on a multinomial logit model for cross-country policy analysis in European countries. Additionally, prospect theory and the notion of mental accounting are used to model the perception of monetary values. The microsimulation forecasts actual market observations with high accuracy, both on the level of aggregate market characteristics as well as on a highly resolved level of distributions of market shares. The presented approach is useful for the assessment of policies that influence individual purchase decisions of new passenger cars; it allows accounting for a highly resolved car fleet and differentiated consumer segments. As a result, the complexity of incentive schemes can be represented and detailed structural changes can be investigated. (author)

  2. How much do incentives affect car purchase? Agent-based microsimulation of consumer choice of new cars. Part 1. Model structure, simulation of bounded rationality, and model validation

    International Nuclear Information System (INIS)

    This article presents an agent-based microsimulation capable of forecasting the effects of policy levers that influence individual choices of new passenger cars. The fundamental decision-making units are households distinguished by sociodemographic characteristics and car ownership. A two-stage model of individual decision processes is employed. In the first stage, individual choice sets are constructed using simple, non-compensatory rules that are based on previously owned cars. Second, decision makers evaluate alternatives in their individual choice set using a multi-attributive weighting rule. The attribute weights are based on a multinomial logit model for cross-country policy analysis in European countries. Additionally, prospect theory and the notion of mental accounting are used to model the perception of monetary values. The microsimulation forecasts actual market observations with high accuracy, both on the level of aggregate market characteristics as well as on a highly resolved level of distributions of market shares. The presented approach is useful for the assessment of policies that influence individual purchase decisions of new passenger cars; it allows accounting for a highly resolved car fleet and differentiated consumer segments. As a result, the complexity of incentive schemes can be represented and detailed structural changes can be investigated. (author)

  3. Modeling Tumor Microenvironments In Vitro

    OpenAIRE

    Wu, Mingming; Melody A Swartz

    2014-01-01

    Tumor progression depends critically upon the interactions between the tumor cells and their microenvironment. The tumor microenvironment is heterogeneous and dynamic; it consists of extracellular matrix, stromal cells, immune cells, progenitor cells, and blood and lymphatic vessels. The emerging fields of tissue engineering and microtechnologies have opened up new possibilities for engineering physiologically relevant and spatially well-defined microenvironments. These in vitro models allow ...

  4. A Watershed-Scale Agent-Based Model Incorporating Agent Learning and Interaction of Farmers' Decisions Subject to Carbon and Miscanthus Prices

    Science.gov (United States)

    Ng, T.; Eheart, J.; Cai, X.; Braden, J. B.

    2010-12-01

    Agricultural watersheds are coupled human-natural systems where the land use decisions of human agents (farmers) affect surface water quality, and in turn, are affected by the weather and yields. The reliable modeling of such systems requires an approach that considers both the human and natural aspects. Agent-based modeling (ABM), representing the human aspect, coupled with hydrologic modeling, representing the natural aspect, is one such approach. ABM is a relatively new modeling paradigm that formulates the system from the perspectives of the individual agents, i.e., each agent is modeled as a discrete autonomous entity with distinct goals and actions. The primary objective of this study is to demonstrate the applicability of this approach to agricultural watershed management. This is done using a semi-hypothetical case study of farmers in the Salt Creek watershed in East-Central Illinois under the influence markets for carbon and second-generation bioenergy crop (specifically, miscanthus). An agent-based model of the system is developed and linked to a hydrologic model of the watershed. The former is based on fundamental economic and mathematical programming principles, while the latter is based on the Soil and Water Assessment Tool (SWAT). Carbon and second-generation bioenergy crop markets are of interest here due to climate change and energy independence concerns. The agent-based model is applied to fifty hypothetical heterogeneous farmers. The farmers' decisions depend on their perceptions of future conditions. Those perceptions are updated, according to a pre-defined algorithm, as the farmers make new observations of prices, costs, yields and the weather with time. The perceptions are also updated as the farmers interact with each other as they share new information on initially unfamiliar activities (e.g., carbon trading, miscanthus cultivation). The updating algorithm is set differently for different farmers such that each is unique in his processing of

  5. A Collective Case Study of Secondary Students' Model-Based Inquiry on Natural Selection through Programming in an Agent-Based Modeling Environment

    Science.gov (United States)

    Xiang, Lin

    This is a collective case study seeking to develop detailed descriptions of how programming an agent-based simulation influences a group of 8 th grade students' model-based inquiry (MBI) by examining students' agent-based programmable modeling (ABPM) processes and the learning outcomes. The context of the present study was a biology unit on natural selection implemented in a charter school of a major California city during spring semester of 2009. Eight 8th grade students, two boys and six girls, participated in this study. All of them were low socioeconomic status (SES). English was a second language for all of them, but they had been identified as fluent English speakers at least a year before the study. None of them had learned either natural selection or programming before the study. The study spanned over 7 weeks and was comprised of two study phases. In phase one the subject students learned natural selection in science classroom and how to do programming in NetLogo, an ABPM tool, in a computer lab; in phase two, the subject students were asked to program a simulation of adaptation based on the natural selection model in NetLogo. Both qualitative and quantitative data were collected in this study. The data resources included (1) pre and post test questionnaire, (2) student in-class worksheet, (3) programming planning sheet, (4) code-conception matching sheet, (5) student NetLogo projects, (6) videotaped programming processes, (7) final interview, and (8) investigator's field notes. Both qualitative and quantitative approaches were applied to analyze the gathered data. The findings suggested that students made progress on understanding adaptation phenomena and natural selection at the end of ABPM-supported MBI learning but the progress was limited. These students still held some misconceptions in their conceptual models, such as the idea that animals need to "learn" to adapt into the environment. Besides, their models of natural selection appeared to be

  6. Agent Based Individual Traffic Guidance

    DEFF Research Database (Denmark)

    Wanscher, Jørgen

    This thesis investigates the possibilities in applying Operations Research (OR) to autonomous vehicular traffic. The explicit difference to most other research today is that we presume that an agent is present in every vehicle - hence Agent Based Individual Traffic guidance (ABIT). The next...... evolutionary step for the in-vehicle route planners is the introduction of two-way communication. We presume that the agent is capable of exactly this. Based on this presumption we discuss the possibilities and define a taxonomy and use this to discuss the ABIT system. Based on a set of scenarios we conclude...... that the system can be divided into two separate constituents. The immediate dispersion, which is used for small areas and quick response, and the individual alleviation, which considers the longer distance decision support. Both of these require intrinsicate models and cost functions which at the beginning...

  7. 基于Agent的复杂系统建模与仿真研究%Research on Agent-based modeling and simulation of complex system

    Institute of Scientific and Technical Information of China (English)

    王亚康; 郭晶; 江汀; 柴新代

    2011-01-01

    Agent-based modeling and simulation provides new ways to research Complex System, inaugurate a new realm of Complex System modeling and simulation compared to traditional modeling methods. The process of complex system modeling is analyzed firsfiy based on agent in the paper, the authors take the aerial defense combat command system of warship fleet for example, then design the model structure of simulation agent entities, and HLA/RTI could be used as the support environment of multi-agent based simulation environment. Based on the work done, the logic architecture and simulation flow are presented for system simulation based on agent. The study of this thesis provides reference for complex system modehng and simulation based on agent in the future.%基于Agent建模与仿真克服了传统的建模技术存在的不足,为复杂系统研究提供了新的思路.在基于Agent的复杂系统建模方法分析的基础上,结合信息对抗环境下护航舰艇编队防空作战系统实例,设计了各个仿真Agent实体的模型结构,采用HLA/RTI作为多Agent仿真环境的支撑环境,在此基础上给出了系统仿真的逻辑结构和仿真流程.该研究为基于Agent建模与仿真的复杂系统研究提供了参考.

  8. Construct validity of agent-based simulation of normative behaviour

    OpenAIRE

    Xenitidou, M; Elsenbroich, C

    2011-01-01

    In this paper we assess the construct validity and theoretical emdeddedness of agent-based models of normative behaviour drawing on experimental social psychology. We contend that social psychology and agent-based modelling share the focus of ‘observing’ the processes and outcomes of the interaction of individual agents. The paper focuses on two from a taxonomy of agent-based models of normative behaviour. This enables the identification of the assumptions the models are built on and in turn,...

  9. Systems of Interaction between the First Sedentary Villages in the Near East Exposed Using Agent-Based Modelling of Obsidian Exchange

    Directory of Open Access Journals (Sweden)

    David Ortega

    2016-03-01

    Full Text Available In the Near East, nomadic hunter-gatherer societies became sedentary farmers for the first time during the transition into the Neolithic. Sedentary life presented a risk of isolation for Neolithic groups. As fluid intergroup interactions are crucial for the sharing of information, resources and genes, Neolithic villages developed a network of contacts. In this paper we study obsidian exchange between Neolithic villages in order to characterize this network of interaction. Using agent-based modelling and elements taken from complex network theory, we model obsidian exchange and compare results with archaeological data. We demonstrate that complex networks of interaction were established at the outset of the Neolithic and hypothesize that the existence of these complex networks was a necessary condition for the success and spread of a new way of living.

  10. Thread Group Multithreading: Accelerating the Computation of an Agent-Based Power System Modeling and Simulation Tool -- C GridLAB-D

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Shuangshuang; Chassin, David P.

    2014-01-06

    GridLAB-DTM is an open source next generation agent-based smart-grid simulator that provides unprecedented capability to model the performance of smart grid technologies. Over the past few years, GridLAB-D has been used to conduct important analyses of smart grid concepts, but it is still quite limited by its computational performance. In order to break through the performance bottleneck to meet the need for large scale power grid simulations, we develop a thread group mechanism to implement highly granular multithreaded computation in GridLAB-D. We achieve close to linear speedups on multithreading version compared against the single-thread version of the same code running on general purpose multi-core commodity for a benchmark simple house model. The performance of the multithreading code shows favorable scalability properties and resource utilization, and much shorter execution time for large-scale power grid simulations.

  11. Learning to Measure Biodiversity: Two Agent-Based Models that Simulate Sampling Methods & Provide Data for Calculating Diversity Indices

    Science.gov (United States)

    Jones, Thomas; Laughlin, Thomas

    2009-01-01

    Nothing could be more effective than a wilderness experience to demonstrate the importance of conserving biodiversity. When that is not possible, though, there are computer models with several features that are helpful in understanding how biodiversity is measured. These models are easily used when natural resources, transportation, and time…

  12. Why Don’t More Farmers Go Organic? Using A Stakeholder-Informed Exploratory Agent-Based Model to Represent the Dynamics of Farming Practices in the Philippines

    Directory of Open Access Journals (Sweden)

    Laura Schmitt Olabisi

    2015-10-01

    Full Text Available In spite of a growing interest in organic agriculture; there has been relatively little research on why farmers might choose to adopt organic methods, particularly in the developing world. To address this shortcoming, we developed an exploratory agent-based model depicting Philippine smallholder farmer decisions to implement organic techniques in rice paddy systems. Our modeling exercise was novel in its combination of three characteristics: first, agent rules were based on focus group data collected in the system of study. Second, a social network structure was built into the model. Third, we utilized variance-based sensitivity analysis to quantify model outcome variability, identify influential drivers, and suggest ways in which further modeling efforts could be focused and simplified. The model results indicated an upper limit on the number of farmers adopting organic methods. The speed of information spread through the social network; crop yields; and the size of a farmer’s plot were highly influential in determining agents’ adoption rates. The results of this stylized model indicate that rates of organic farming adoption are highly sensitive to the yield drop after switchover to organic techniques, and to the speed of information spread through existing social networks. Further research and model development should focus on these system characteristics.

  13. Hybrid equation/agent-based model of ischemia-induced hyperemia and pressure ulcer formation predicts greater propensity to ulcerate in subjects with spinal cord injury.

    Directory of Open Access Journals (Sweden)

    Alexey Solovyev

    Full Text Available Pressure ulcers are costly and life-threatening complications for people with spinal cord injury (SCI. People with SCI also exhibit differential blood flow properties in non-ulcerated skin. We hypothesized that a computer simulation of the pressure ulcer formation process, informed by data regarding skin blood flow and reactive hyperemia in response to pressure, could provide insights into the pathogenesis and effective treatment of post-SCI pressure ulcers. Agent-Based Models (ABM are useful in settings such as pressure ulcers, in which spatial realism is important. Ordinary Differential Equation-based (ODE models are useful when modeling physiological phenomena such as reactive hyperemia. Accordingly, we constructed a hybrid model that combines ODEs related to blood flow along with an ABM of skin injury, inflammation, and ulcer formation. The relationship between pressure and the course of ulcer formation, as well as several other important characteristic patterns of pressure ulcer formation, was demonstrated in this model. The ODE portion of this model was calibrated to data related to blood flow following experimental pressure responses in non-injured human subjects or to data from people with SCI. This model predicted a higher propensity to form ulcers in response to pressure in people with SCI vs. non-injured control subjects, and thus may serve as novel diagnostic platform for post-SCI ulcer formation.

  14. Competitive allocation of resources on a network: an agent-based model of air companies competing for the best routes

    CERN Document Server

    Gurtner, Gérald; Lillo, Fabrizio

    2014-01-01

    We present a stylized model of the allocation of resources on a network. By considering as a concrete example the network of sectors of the airspace, where each node is a sector characterized by a maximal number of simultaneously present aircraft, we consider the problem of air companies competing for the allocation of the airspace. Each company is characterized by a cost function, weighting differently punctuality and length of the flight. We consider the model in the presence of pure and mixed populations of types of airline companies and we study how the equilibria depends on the characteristics of the network.

  15. Characteristic time scales of tick quotes on foreign currency markets: empirical study and agent-based model

    CERN Document Server

    Sato, A H

    2006-01-01

    Power spectrum densities for the number of tick quotes per minute (market activity) on three currency markets (USD/JPY, EUR/USD, and JPY/EUR) for periods from January 1999 to December 2000 are analyzed. We find some peaks on the power spectrum densities at a few minutes. We develop the double-threshold agent model and confirm that stochastic resonance occurs for the market activity of this model. We propose a hypothesis that the periodicities found on the power spectrum densities can be observed due to stochastic resonance.

  16. Analysis of Tsunami Evacuation Issues Using Agent Based Modeling. A Case Study of the 2011 Tohoku Tsunami in Yuriage, Natori.

    Science.gov (United States)

    Mas, E.; Takagi, H.; Adriano, B.; Hayashi, S.; Koshimura, S.

    2014-12-01

    The 2011 Great East Japan earthquake and tsunami reminded that nature can exceed structural countermeasures like seawalls, breakwaters or tsunami gates. In such situations it is a challenging task for people to find nearby haven. This event, as many others before, confirmed the importance of early evacuation, tsunami awareness and the need for developing much more resilient communities with effective evacuation plans. To support reconstruction activities and efforts on developing resilient communities in areas at risk, tsunami evacuation simulation can be applied to tsunami mitigation and evacuation planning. In this study, using the compiled information related to the evacuation behavior at Yuriage in Natori during the 2011 tsunami, we simulated the evacuation process and explored the reasons for the large number of fatalities in the area. It was found that residents did evacuate to nearby shelter areas, however after the tsunami warning was increased some evacuees decided to conduct a second step evacuation to a far inland shelter. Simulation results show the consequences of such decision and the outcomes when a second evacuation would not have been performed. The actual reported number of fatalities in the event and the results from simulation are compared to verify the model. The case study shows the contribution of tsunami evacuation models as tools to be applied for the analysis of evacuees' decisions and the related outcomes. In addition, future evacuation plans and activities for reconstruction process and urban planning can be supported by the results provided from this kind of tsunami evacuation models.

  17. Agent-based simulation of animal behaviour

    NARCIS (Netherlands)

    Jonker, C.M.; Treur, J.

    1998-01-01

    In this paper it is shown how animal behaviour can be simulated in an agent-based manner. Different models are shown for different types of behaviour, varying from purely reactive behaviour to pro-active, social and adaptive behaviour. The compositional development method for multi-agent systems DES

  18. Synthetic benchmark model for parallel agent-based simulation%面向并行Agent仿真的合成基准测试模型

    Institute of Scientific and Technical Information of China (English)

    余文广; 王维平; 侯洪涛; 李群

    2012-01-01

    In order to evaluate the performance of parallel simulation algorithms, there is a need for a benchmark model. To solve the problem that there is currently lack of such a common benchmark model that is independent of applications in the parallel agent-based simulation (PABS) research community, based on the design principles of parallel HOLD which is a classic synthetic benchmark model for parallel discrete event simulations (PDES) , a common benchmark model for PABS is proposed according to the characteristics of agent-based simulations (ABS). This model can easily synthesize various required workloads based on application characteristics and exclude the impact of elements related to specific applications on the performance analysis so as to provide a common benchmark for different PABS researchers. Finally, with this model, the impact of the computation granularity of agents and the number of processors on the speedup is analyzed experimentally.%为了评估并行仿真算法的性能,需要建立一个基准测试模型.针对并行Agent仿真研究领域中缺乏一种与应用无关的基准测试模型这一问题,在借鉴并行离散事件仿真中经典的合成测试模型PHOLD设计思想的基础上,根据基于Agent仿真的特点,提出面向并行Agent仿真的合成基准测试模型,利用该模型可以方便地合成符合不同应用特点的计算负载,去除与应用相关的因素对性能分析的影响,能够为不同的并行Agent仿真研究者提供一个公共的测试基准.最后,采用该模型从实验层次上分析了Agent计算粒度、所采用的处理器数目等因素对并行Agent仿真加速比的影响.

  19. An Agent-Based Model of Private Woodland Owner Management Behavior Using Social Interactions, Information Flow, and Peer-To-Peer Networks.

    Directory of Open Access Journals (Sweden)

    Emily Silver Huff

    Full Text Available Privately owned woodlands are an important source of timber and ecosystem services in North America and worldwide. Impacts of management on these ecosystems and timber supply from these woodlands are difficult to estimate because complex behavioral theory informs the owner's management decisions. The decision-making environment consists of exogenous market factors, internal cognitive processes, and social interactions with fellow landowners, foresters, and other rural community members. This study seeks to understand how social interactions, information flow, and peer-to-peer networks influence timber harvesting behavior using an agent-based model. This theoretical model includes forested polygons in various states of 'harvest readiness' and three types of agents: forest landowners, foresters, and peer leaders (individuals trained in conservation who use peer-to-peer networking. Agent rules, interactions, and characteristics were parameterized with values from existing literature and an empirical survey of forest landowner attitudes, intentions, and demographics. The model demonstrates that as trust in foresters and peer leaders increases, the percentage of the forest that is harvested sustainably increases. Furthermore, peer leaders can serve to increase landowner trust in foresters. Model output and equations will inform forest policy and extension/outreach efforts. The model also serves as an important testing ground for new theories of landowner decision making and behavior.

  20. An Agent-Based Model of Private Woodland Owner Management Behavior Using Social Interactions, Information Flow, and Peer-To-Peer Networks.

    Science.gov (United States)

    Huff, Emily Silver; Leahy, Jessica E; Hiebeler, David; Weiskittel, Aaron R; Noblet, Caroline L

    2015-01-01

    Privately owned woodlands are an important source of timber and ecosystem services in North America and worldwide. Impacts of management on these ecosystems and timber supply from these woodlands are difficult to estimate because complex behavioral theory informs the owner's management decisions. The decision-making environment consists of exogenous market factors, internal cognitive processes, and social interactions with fellow landowners, foresters, and other rural community members. This study seeks to understand how social interactions, information flow, and peer-to-peer networks influence timber harvesting behavior using an agent-based model. This theoretical model includes forested polygons in various states of 'harvest readiness' and three types of agents: forest landowners, foresters, and peer leaders (individuals trained in conservation who use peer-to-peer networking). Agent rules, interactions, and characteristics were parameterized with values from existing literature and an empirical survey of forest landowner attitudes, intentions, and demographics. The model demonstrates that as trust in foresters and peer leaders increases, the percentage of the forest that is harvested sustainably increases. Furthermore, peer leaders can serve to increase landowner trust in foresters. Model output and equations will inform forest policy and extension/outreach efforts. The model also serves as an important testing ground for new theories of landowner decision making and behavior.

  1. A Modeling Method of Agent Based on Milk-run in Automobile Parts%基于Agent的汽车零部件循环取货模型

    Institute of Scientific and Technical Information of China (English)

    屈新怀; 盛敏; 丁必荣

    2013-01-01

    Milk-Run,as a new method in supply system management in automobile pasts inbound logistic,can be considered as a kind of complex adaptive system.It is composed of suppliers,3PL,and automobile firm.According to its conceptual model,the agent-based model method has been used.After define the research purpose,the abstract lever of these agents focus on the corporate sector in the milk-run system,such as the product Agent,purchase Agent,schedule Agent etc.First to analysis the internal model of all agents,then to adopt the formalization description method to describe the agent behaviors.At last interactive processing between these agents are been explained in Agent UML.Apparently,the agent-based modeling method has a strong performer on the principle of milk-run system.It will be easy to achieve the simulation about the milk-run based on the agent model.%汽车零部件的循环取货模式作为一种新型物料供应体系,是由供应商、3PL、主机厂多个主体组成,属于复杂适应性系统.根据循环取货的概念模型,采用多Agent建模理论对循环取货进行建模.将目标系统的Agent粒度抽象为企业级以下的职能部门,设计生产Agent、采购Agent、调度Agent等几类主体.分析Agent内部模型,并采用形式化方法对主体行为进行描述,应用Agent UML分析主体之间的动态交互行为.基于Agent的建模描述了循环取货的运行机制,从而为后续的计算机仿真实现提供基础.

  2. Two Strategies Of Agent-Based Modelling Application For Management Of Lakeland Landscapes At A Regional Scale

    Directory of Open Access Journals (Sweden)

    Giełda-Pinas Katarzyna

    2015-09-01

    Full Text Available This work presents two different strategies of ABM for management of selected lakeland landscapes and their impact on sustainable development. Two different lakeland research areas as well as two different sets of agents and their decision rules were compared. In Strategy 1 decisions made by farmers and their influence on the land use/cover pattern as well as the indirect consequence of phosphorus and nitrogen delivery to the water bodies were investigated. In this strategy, a group of farmer agents is encouraged to participate in an agri-environmental program. The Strategy 2 combines the decisions of farmers, foresters and local authorities. The agents in the model share a common goal to produce a spatial plan. The land use/cover patterns arising from different attitudes and decision rules of the involved actors were investigated. As the basic spatial unit, the first strategy employed a landscape unit, i.e. lake catchment whereas the second strategy used an administrative unit, i.e. commune. Both strategies resulted in different land use/cover patterns and changes, which were evaluated in terms of sustainability policy. The main conclusion for Strategy 1 is that during 5 years of farmer’s participation in the agri-environmental program, there was significant decrease of nutrient leaching to the lake. The main conclusion for Strategy 2 should be stated that cooperating of the agents is better for the natural environment than the competitions between them. In both strategies, agents’ decisions influence the environment but different spatial units of analysis express this environment.

  3. Developing an Agent-based Model for the Depot-based Water Allocation System in the Bakken Field in Western North Dakota

    Science.gov (United States)

    Lin, T.; Lin, Z.; Lim, S.; Borders, M.

    2015-12-01

    The oil production at the Bakken Shale increased more than ten times from 2008 to 2013 due to technological advancement in hydraulic fracturing and North Dakota has become the second largest oil producing state in the U.S. behind only Texas since 2012. On average it requires about 2-4 million gallons of freshwater to complete one oil well in the Bakken field and the number of oil well completions (i.e., hydraulic fracturing) in the Bakken field increased from 500 in 2008 to 2085 in 2013. A large quantity of freshwater used for hydraulic fracturing renders a significant impact on water resource management in the semi-arid region. A novel water allocation system - water depots - was spontaneously created to distribute surface and ground water for industrial uses. A GIS-based multi-agent model is developed to simulate the emergent patterns and dynamics of the water depot-based water allocation system and to explore its economic and environmental consequences. Four different types of water depot are defined as agents and water price, climate condition, water source, geology, and other physical and economic constraints are considered in the model. Decentralized optimization algorithm will be used to determine the agents' behaviors. The agent-based model for water depots will be coupled with hydrological models to improve the region's water resources management.

  4. Cross-site comparison of land-use decision-making and its consequences across land systems with a generalized agent-based model.

    Directory of Open Access Journals (Sweden)

    Nicholas R Magliocca

    Full Text Available Local changes in land use result from the decisions and actions of land-users within land systems, which are structured by local and global environmental, economic, political, and cultural contexts. Such cross-scale causation presents a major challenge for developing a general understanding of how local decision-making shapes land-use changes at the global scale. This paper implements a generalized agent-based model (ABM as a virtual laboratory to explore how global and local processes influence the land-use and livelihood decisions of local land-users, operationalized as settlement-level agents, across the landscapes of six real-world test sites. Test sites were chosen in USA, Laos, and China to capture globally-significant variation in population density, market influence, and environmental conditions, with land systems ranging from swidden to commercial agriculture. Publicly available global data were integrated into the ABM to model cross-scale effects of economic globalization on local land-use decisions. A suite of statistics was developed to assess the accuracy of model-predicted land-use outcomes relative to observed and random (i.e. null model landscapes. At four of six sites, where environmental and demographic forces were important constraints on land-use choices, modeled land-use outcomes were more similar to those observed across sites than the null model. At the two sites in which market forces significantly influenced land-use and livelihood decisions, the model was a poorer predictor of land-use outcomes than the null model. Model successes and failures in simulating real-world land-use patterns enabled the testing of hypotheses on land-use decision-making and yielded insights on the importance of missing mechanisms. The virtual laboratory approach provides a practical framework for systematic improvement of both theory and predictive skill in land change science based on a continual process of experimentation and model

  5. Lipid Raft Size and Lipid Mobility in Non-raft Domains Increase during Aging and Are Exacerbated in APP/PS1 Mice Model of Alzheimer's Disease. Predictions from an Agent-Based Mathematical Model.

    Science.gov (United States)

    Santos, Guido; Díaz, Mario; Torres, Néstor V

    2016-01-01

    A connection between lipid rafts and Alzheimer's disease has been studied during the last decades. Mathematical modeling approaches have recently been used to correlate the effects of lipid composition changes in the physicochemical properties of raft-like membranes. Here we propose an agent based model to assess the effect of lipid changes in lipid rafts on the evolution and progression of Alzheimer's disease using lipid profile data obtained in an established model of familial Alzheimer's disease. We have observed that lipid raft size and lipid mobility in non-raft domains are two main factors that increase during age and are accelerated in the transgenic Alzheimer's disease mouse model. The consequences of these changes are discussed in the context of neurotoxic amyloid β production. Our agent based model predicts that increasing sterols (mainly cholesterol) and long-chain polyunsaturated fatty acids (LCPUFA) (mainly DHA, docosahexaenoic acid) proportions in the membrane composition might delay the onset and progression of the disease.

  6. 基于Agent的居民就医选择建模与仿真%Agent-based Modeling and Simulation Research into Residents Healthcare Choice

    Institute of Scientific and Technical Information of China (English)

    程贲; 李兴兵; 鲁延京; 谭跃进

    2009-01-01

    基于Agent建模仿真是医疗服务领域中问题研究和政策分析的一种新方法.在分析目前医疗领域中居民就医选择现状的基础上,基于Agent的建模方法,对医疗系统中的主要对象--医院、社区医疗服务机构、居民的行为进行了建模,开发了基于Anylogic的居民就医选择的仿真原型,研究了居民的就医选择问题,分析扩大不同医疗机构的费用差距及增加区域内社区医疗服务机构数量两项政策对居民就医选择的影响.实验结果说明通过调节医院与社区诊所的医疗服务的价格比,能够影响居民就医选择,但增加医院的医疗服务的价格会造成部分低收入居民无法就医;区域内社区诊所与医院的比例在2~4倍时,对降低居民无法就医的比例是有效的.%Agent-based modeling and simulation is a new methodology in the field of healthcare service research and relevant policy analysis. Applying agent-based modeling and simulation methodology, we research the problem of residents' healthcare selection and construct health service models for hospitals, residents and communities. Applying the simulation tool -AnyLogic, we analyze the effects of two policies on residents' health care choice, which involve enlarging the price gap of different healthcare institutions and increasing the number of healthcare service agencies in communities within a region. The experiment result illustrates that changing the cost ratio of hospital and community service has a significant impact on residents' selection decision, while the rising of the price of healthcare service makes residents with low income unable to afford the expense of healthcare service, and that the proper ratio of the number of community health service agencies to that of hospitals within a certain region is 2 to 4.

  7. Agent-based model for electricity consumption and storage to evaluate economic viability of tariff arbitrage for residential sector demand response

    International Nuclear Information System (INIS)

    Highlights: • Storage-based demand response (loadshifting) is underutilized in residential sector. • Economics (arbitrage savings versus equipment cost) are not well understood. • Stochastic demand models and real-life tariffs can illuminate economic viability. • A range of available storage options provide economically viable DR. • Daily/seasonal stochastic demand variations crucial to understanding optimum capacity. - Abstract: Demand response (DR) is one of many approaches to address temporal mismatches in demand and supply of grid electricity. More common in the commercial sector, DR usually refers to reducing consumption at certain hours or seasons, thus reducing peak demand from the grid. In the residential sector, where sophisticated appliance-level controls such as automatic dimming of lights or on-demand lowering of air conditioning are less common, building-based electricity storage to shift grid consumption from peak to off-peak times could provide DR without requiring consumers to operate their appliances on shifted or reduced schedules: Storage would be dispatched to appliances as needed while still shaving peaks on the grid. Technologically, storage and two-way-inverters are readily available to enable such residential DR. Economically, however, the situation is less clear. Specifically, are time-varying electricity tariffs available such that electricity cost reduction via arbitrage could offset manufacturing, financing, and installation costs of the required storage? To address this question we (i) devise an agent-based appliance-level stochastic model to simulate the electricity demand of an average U.S. household; (ii) loadshift the demand via simple dispatch strategies; and (iii) determine potential profits to the building owner, i.e. reduced electricity cost of the modified demand with realistic tariffs (Con Edison, NY) minus storage cost. We determine the economic viability for a range of traditional and advanced storage technologies

  8. Modeling the emergence of multi-protein dynamic structures by principles of self-organization through the use of 3DSpi, a multi-agent-based software

    Directory of Open Access Journals (Sweden)

    Beslon Guillaume

    2005-09-01

    Full Text Available Abstract Background There is an increasing need for computer-generated models that can be used for explaining the emergence and predicting the behavior of multi-protein dynamic structures in cells. Multi-agent systems (MAS have been proposed as good candidates to achieve this goal. Results We have created 3DSpi, a multi-agent based software that we used to explore the generation of multi-protein dynamic structures. Being based on a very restricted set of parameters, it is perfectly suited for exploring the minimal set of rules needed to generate large multi-protein structures. It can therefore be used to test the hypothesis that such structures are formed and maintained by principles of self-organization. We observed that multi-protein structures emerge and that the system behavior is very robust, in terms of the number and size of the structures generated. Furthermore, the generated structures very closely mimic spatial organization of real life multi-protein structures. Conclusion The behavior of 3DSpi confirms the considerable potential of MAS for modeling subcellular structures. It demonstrates that robust multi-protein structures can emerge using a restricted set of parameters and allows the exploration of the dynamics of such structures. A number of easy-to-implement modifications should make 3DSpi the virtual simulator of choice for scientists wishing to explore how topology interacts with time, to regulate the function of interacting proteins in living cells.

  9. Exploring Tradeoffs in Demand-side and Supply-side Management of Urban Water Resources using Agent-based Modeling and Evolutionary Computation

    Science.gov (United States)

    Kanta, L.; Berglund, E. Z.

    2015-12-01

    Urban water supply systems may be managed through supply-side and demand-side strategies, which focus on water source expansion and demand reductions, respectively. Supply-side strategies bear infrastructure and energy costs, while demand-side strategies bear costs of implementation and inconvenience to consumers. To evaluate the performance of demand-side strategies, the participation and water use adaptations of consumers should be simulated. In this study, a Complex Adaptive Systems (CAS) framework is developed to simulate consumer agents that change their consumption to affect the withdrawal from the water supply system, which, in turn influences operational policies and long-term resource planning. Agent-based models are encoded to represent consumers and a policy maker agent and are coupled with water resources system simulation models. The CAS framework is coupled with an evolutionary computation-based multi-objective methodology to explore tradeoffs in cost, inconvenience to consumers, and environmental impacts for both supply-side and demand-side strategies. Decisions are identified to specify storage levels in a reservoir that trigger (1) increases in the volume of water pumped through inter-basin transfers from an external reservoir and (2) drought stages, which restrict the volume of water that is allowed for residential outdoor uses. The proposed methodology is demonstrated for Arlington, Texas, water supply system to identify non-dominated strategies for an historic drought decade. Results demonstrate that pumping costs associated with maximizing environmental reliability exceed pumping costs associated with minimizing restrictions on consumer water use.

  10. Use of an agent-based simulation model to evaluate a mobile-based system for supporting emergency evacuation decision making.

    Science.gov (United States)

    Tian, Yu; Zhou, Tian-Shu; Yao, Qin; Zhang, Mao; Li, Jing-Song

    2014-12-01

    Recently, mass casualty incidents (MCIs) have been occurring frequently and have gained international attention. There is an urgent need for scientifically proven and effective emergency responses to MCIs, particularly as the severity of incidents is continuously increasing. The emergency response to MCIs is a multi-dimensional and multi-participant dynamic process that changes in real-time. The evacuation decisions that assign casualties to different hospitals in a region are very important and impact both the results of emergency treatment and the efficiency of medical resource utilization. Previously, decisions related to casualty evacuation were made by an incident commander with emergency experience and in accordance with macro emergency guidelines. There are few decision-supporting tools available to reduce the difficulty and psychological pressure associated with the evacuation decisions an incident commander must make. In this study, we have designed a mobile-based system to collect medical and temporal data produced during an emergency response to an MCI. Using this information, our system's decision-making model can provide personal evacuation suggestions that improve the overall outcome of an emergency response. The effectiveness of our system in reducing overall mortality has been validated by an agent-based simulation model established to simulate an emergency response to an MCI. PMID:25354665

  11. Using Agent-Based Modelling to Predict the Role of Wild Refugia in the Evolution of Resistance of Sea Lice to Chemotherapeutants.

    Science.gov (United States)

    McEwan, Gregor F; Groner, Maya L; Fast, Mark D; Gettinby, George; Revie, Crawford W

    2015-01-01

    A major challenge for Atlantic salmon farming in the northern hemisphere is infestation by the sea louse parasite Lepeophtheirus salmonis. The most frequent method of controlling these sea louse infestations is through the use of chemical treatments. However, most major salmon farming areas have observed resistance to common chemotherapeutants. In terrestrial environments, many strategies employed to manage the evolution of resistance involve the use of refugia, where a portion of the population is left untreated to maintain susceptibility. While refugia have not been deliberately used in Atlantic salmon farming, wild salmon populations that migrate close to salmon farms may act as natural refugia. In this paper we describe an agent-based model that explores the influence of different sizes of wild salmon populations on resistance evolution in sea lice on a salmon farm. Using the model, we demonstrate that wild salmon populations can act as refugia that limit the evolution of resistance in the sea louse populations. Additionally, we demonstrate that an increase in the size of the population of wild salmon results in an increased effect in slowing the evolution of resistance. We explore the effect of a population fitness cost associated with resistance, finding that in some cases it substantially reduces the speed of evolution to chemical treatments. PMID:26485023

  12. Using Agent-Based Modelling to Predict the Role of Wild Refugia in the Evolution of Resistance of Sea Lice to Chemotherapeutants.

    Directory of Open Access Journals (Sweden)

    Gregor F McEwan

    Full Text Available A major challenge for Atlantic salmon farming in the northern hemisphere is infestation by the sea louse parasite Lepeophtheirus salmonis. The most frequent method of controlling these sea louse infestations is through the use of chemical treatments. However, most major salmon farming areas have observed resistance to common chemotherapeutants. In terrestrial environments, many strategies employed to manage the evolution of resistance involve the use of refugia, where a portion of the population is left untreated to maintain susceptibility. While refugia have not been deliberately used in Atlantic salmon farming, wild salmon populations that migrate close to salmon farms may act as natural refugia. In this paper we describe an agent-based model that explores the influence of different sizes of wild salmon populations on resistance evolution in sea lice on a salmon farm. Using the model, we demonstrate that wild salmon populations can act as refugia that limit the evolution of resistance in the sea louse populations. Additionally, we demonstrate that an increase in the size of the population of wild salmon results in an increased effect in slowing the evolution of resistance. We explore the effect of a population fitness cost associated with resistance, finding that in some cases it substantially reduces the speed of evolution to chemical treatments.

  13. Agent-based simulation of animal behaviour

    OpenAIRE

    Jonker, C.M.; Treur, J.

    1998-01-01

    In this paper it is shown how animal behaviour can be simulated in an agent-based manner. Different models are shown for different types of behaviour, varying from purely reactive behaviour to pro-active, social and adaptive behaviour. The compositional development method for multi-agent systems DESIRE and its software environment supports the conceptual and detailed design, and execution of these models. Experiments reported in the literature on animal behaviour have been simulated for a num...

  14. Exploring Tradeoffs in Demand-Side and Supply-Side Management of Urban Water Resources Using Agent-Based Modeling and Evolutionary Computation

    Directory of Open Access Journals (Sweden)

    Lufthansa Kanta

    2015-11-01

    Full Text Available Urban water supply systems may be managed through supply-side and demand-side strategies, which focus on water source expansion and demand reductions, respectively. Supply-side strategies bear infrastructure and energy costs, while demand-side strategies bear costs of implementation and inconvenience to consumers. To evaluate the performance of demand-side strategies, the participation and water use adaptations of consumers should be simulated. In this study, a Complex Adaptive Systems (CAS framework is developed to simulate consumer agents that change their consumption to affect the withdrawal from the water supply system, which, in turn influences operational policies and long-term resource planning. Agent-based models are encoded to represent consumers and a policy maker agent and are coupled with water resources system simulation models. The CAS framework is coupled with an evolutionary computation-based multi-objective methodology to explore tradeoffs in cost, inconvenience to consumers, and environmental impacts for both supply-side and demand-side strategies. Decisions are identified to specify storage levels in a reservoir that trigger: (1 increases in the volume of water pumped through inter-basin transfers from an external reservoir; and (2 drought stages, which restrict the volume of water that is allowed for residential outdoor uses. The proposed methodology is demonstrated for Arlington, Texas, water supply system to identify non-dominated strategies for an historic drought decade. Results demonstrate that pumping costs associated with maximizing environmental reliability exceed pumping costs associated with minimizing restrictions on consumer water use.

  15. Agent based automated trust negotiation model%一种基于代理的自动信任协商模型

    Institute of Scientific and Technical Information of China (English)

    李开; 卢正鼎; 李瑞轩; 唐卓

    2007-01-01

    To enhance the practicability of the trust negotiation system,an agent based automated trust negotiation model (ABAM) is proposed.The ABAM introduces an agent to keep the negotiation process with no human intervention.Meanwhile,the ABAM specifies the format of a meta access control policy,and adopts credentials with flexible format to meet the requirements of access control policies instead of disclosing the whole contents of a certificate.Furthermore,the ABAM uses asymmetric functions with a high security intensity to encrypt the transmitting message,which can prevent information from being attacked.Finally,the ABAM presents a new negotiation protocol to guide the negotiation process.A use case is studied to illuminate that the ABAM is sound and reasonable.Compared with the existing work,the intelligence,privacy and negotiation efficiency are improved in the ABAM.%为增强信任协商系统的实用性,提出一种基于代理的自动信任协商模型(ABAM).ABAM引进代理使协商过程免于人工干涉.同时,ABAM指定了元策略格式,使用这种格式灵活的信任凭证来满足访问控制策略要求,而不需披露数字证书的全部内容.此外,ABAM使用高强度的非对称函数加密传输消息,能防止消息遭受攻击.最后,模型中提出一种新的协商协议来指导协商进行.事例分析表明,ABAM是健全和合理的.与现有工作相比,ABAM在智能性、保密性和协商效率方面得到了改进.

  16. Tipping Points towards Regional Forest or Urban Transition in Stressed Rural Areas: An Agent-based Modelling Application of Socio-Economic Shifts in Rural Vermont US

    Science.gov (United States)

    Tsai, Y.; Turnbull, S.; Zia, A.

    2015-12-01

    In rural areas where farming competes with urban development and environmental amenities, urban and forest transitions occur simultaneously at different locales with different rates due to the underlying socio-economic shifts. Here we develop an interactive land use transition agent-based model (ILUTABM) in which farmers' land use decisions are made contingent on expansion and location choices of urban businesses and urban residences, as well as farmers' perceived ecosystem services produced by their land holdings. The ILUTABM simulates heterogeneity in land use decisions at parcel levels by differentiating decision making processes for agricultural and urban landowners. Landowners are simulated to make land-use transition decisions as bounded rational agents that maximize their partial expected utility functions under different underlying socio-economic conditions given the category of a landowner and the spatial characteristics of the landowner's landholdings. The ILUTABM is parameterized by spatial data sets such as National Land Cover Database (NLCD), zoning, parcels, property prices, US census, farmers surveys, building/facility characteristics, soil, slope and elevation. We then apply the ILUTABM to the rural Vermont landscape, located in the Northeast Arm District of Lake Champlain and the downstream sub-watersheds of Missisquoi River, to generate phase transitions of rural land towards urban land near peri-urban areas and towards forest land near financially stressed farmlands during 2001-2051. Possible tipping point trajectories of rural land towards regional forest or urban transition are simulated under three socio-economic scenarios: business as usual (ILUTABM calibrated to 2011 NLCD), increased incentives for conservation easements, and increased incentives for attracting urban residences and businesses.

  17. Agent Based Patient Scheduling Using Heuristic Algorithm

    Directory of Open Access Journals (Sweden)

    Juliet A Murali

    2010-01-01

    Full Text Available This paper describes about an agent based approach to patient scheduling using experience based learning. A heuristic algorithm is also used in the proposed framework. The evaluation on different learning techniques shows that the experience based learning (EBL gives better solution. The processing time decreases as the experience increases. The heuristic algorithm make use of EBL in calculating the processing time. The main objective of this patient scheduling system is to reduce the waiting time of patient in hospitals and to complete their treatment in minimum required time. The framework is implemented in JADE. In this approach the patients and resources are represented as patient agents (PA and resource agents (RA respectively. Even though mathematical model give optimal solution, the computational complexity increases for large size problems. Heuristic solution gives better solution for large size problems. The comparisons of the proposed framework with other scheduling rules shows that an agent based approach to patient scheduling using EBL is better.

  18. Agent农业土地变化模型研究进展%Progress of agent-based agricultural land change modeling: a review

    Institute of Scientific and Technical Information of China (English)

    余强毅; 吴文斌; 杨鹏; 唐华俊; 周清波; 陈仲新

    2013-01-01

    农业土地变化是全球变化与可持续研究的热点,当前研究虽取得了长足进展,但仍存在诸多不足,集中表现在对农业土地系统复杂性与动态性的认识不够.近年来,基于Agent的农业土地变化研究(农业ABM/LUCC,Agent-based agricultural land change modeling)逐渐兴起,极大的丰富了传统研究的理论与方法,具体表现在:(1)农业ABM/LUCC将微观层面的人类个体行为整合进土地变化研究框架,有助于更加清楚的认识农业土地系统的“人类-自然”综合复杂性问题.(2)农业ABM/LUCC能够动态表达土地系统变化的内生反馈机制,有助于弥补传统的静态土地变化驱动机制分析的不足.(3)基于ABM/LUCC的农业土地利用格局动态研究是整合“人类-自然”综合研究的关键桥梁,农业ABM/LUCC能够与其他生物地球物理模型或经济模型动态嵌套,使多尺度、多维度综合模型研究成为可能.然而,农业ABM/LUCC研究也存在诸多挑战,如理论研究滞后于应用研究,大尺度应用难以开展,以及农户行为的模拟结果很难得到校验等.%Agricultural land use and land cover change ( Agri-LUCC) is one of the key issues among global change and sustainability studies.Year-on-year progress makes "agricultural land change" to be an emerging interdisciplinary science.As an effective tool for understanding the driver, process and consequence of Agri-LUCC, spatially-explicit land change models have successfully applied in representing agricultural landscapes and its possible developments across scales.Although several breakthroughs have been achieved by traditional land change modeling, there are still many crucial issues remain unsolved, especially the insufficient cognition on the complexity and dynamics of agricultural land systems.Recently, some researchers begin to combine agent-based models (ABM, one of the key tools for complex system studies) with land change models, bringing a new emergence of

  19. Jogo da Minoria: um modelo baseado em agentes aplicado ao mercado financeiro Minority Game: an agent-based model applied to financial market

    Directory of Open Access Journals (Sweden)

    Antonio Fernando Crepaldi

    2012-12-01

    Full Text Available Nos últimos anos houve uma contribuição significativa dos físicos para a construção de um tipo de modelo baseado em agentes que busca reproduzir, em simulação computacional, o comportamento do mercado financeiro. Esse modelo, chamado Jogo da Minoria consiste de um grupo de agentes que vão ao mercado comprar ou vender ativos. Eles tomam decisões com base em estratégias e, por meio delas, os agentes estabelecem um intrincado jogo de competição e coordenação pela distribuição da riqueza. O modelo tem demonstrado resultados bastante ricos e surpreendentes, tanto na dinâmica do sistema como na capacidade de reproduzir características estatísticas e comportamentais do mercado financeiro. Neste artigo, são apresentadas a estrutura e a dinâmica do Jogo da Minoria, bem como as contribuições recentes relacionadas ao Jogo da Minoria denominado de Grande Canônico, que é um modelo mais bem ajustado às características do mercado financeiro e reproduz as regularidades estatísticas do preço dos ativos chamadas fatos estilizados.Over the past ten years physicists have made a significant contribution to the building of an agent-based model to reproduce the behavior of financial markets using computer simulation. This model, called the Minority Game, consists of a group of agents that buy or sell assets. They make decisions based on strategies, and through them the agents establish an intricate game of competition and coordination resulting in the distribution of wealth. The model has shown outstanding surprising results concerning both the dynamics of the system and the ability to reproduce statistical and behavior characteristics of the financial market. In this study, the structure and dynamics of the Minority Game and the recent contributions related to the Grand Canonical Minority game, a model which is better adapted to the characteristics of the financial market and reproduce the statistical regularities of asset prices (called

  20. Genetically engineered mouse models of pituitary tumors

    OpenAIRE

    DavidACano; AlfonsoSoto-Moreno

    2014-01-01

    Animal models constitute valuable tools for investigating the pathogenesis of cancer as well as for preclinical testing of novel therapeutics approaches. However, the pathogenic mechanisms of pituitary tumor formation remain poorly understood, particularly in sporadic adenomas, thus making it a challenge to model pituitary tumors in mice. Nevertheless, genetically engineered mouse models (GEMMs) of pituitary tumors have provided important insight into pituitary tumor biology. In this paper, w...