Agent Based Simulation

We define an individual-based probabilistic model of a sole (Solea solea) behaviour. The individual model is given in terms of an Extended Probabilistic Discrete Timed Automaton (EPDTA), a new formalism that is introduced in the paper and that is shown to be interpretable as a Markov decision process. A given EPDTA model can be probabilistically model-checked by giving a suitable transla-tion into syntax accepted by existing model-checkers. In order to simulate the dynamics of a given population of soles in different environmental scenarios, an agent-based simulation environment is defined in which each agent implements the behaviour of the given EPDTA model. By varying the probabilities and the characteristic functions embedded in the EPDTA model it is possible to repre-sent different scenarios and to tune the model itself by comparing the results of the simulations with real data about the sole stock in the North Adriatic sea, available from the recent project SoleMon. The simulat...

C'est avec tr ès grand plaisir que je souhaite remercier tous ceux qui m'ont aid é ou soutenu durant les dix derni ères ann ées de ma carri ère, que r ésume ce m émoire. Je remercie REN É MANDIAU de m'avoir fait l'honneur de pr ésider mon jury ; ainsi que MARIE-PIERRE GLEIZES, CYRILLE BERTELLE et OLIVIER BOISSIER d'avoir accept é la lourde t âche de rapporteur ; et FRANC ¸OIS CHARPILLET d'avoir participer à mon jury et évaluer mon travail. Nos échanges ont confirm é ou ouvert des perspectives passionnantes. ABDERRAFIAA KOUKAM m'a recrut é dans son équipe. Je le remercie pour la libert é d'action et la confiance qu'il m'a accord ées. Je fais partie des nombreux chercheurs qui lui doivent leur carri ère et qui partagent des valeurs qu'il aura transmises par ses conseils et son exemple. Je lui suis profond ément reconnaissant pour tout ce qu'il a fait et continue à faire pour moi. VINCENT HILAIRE a ét é le premier à avoir propos é une approche organisationnelle dans notre laboratoire. Ses qualit és scientifiques et humaines ont ét é autant d'inspirations pour g érer mes activit és de recherche. C'est avec un grand plaisir que je le remercie d'avoir accept é de participer à mon jury. NICOLAS GAUD a ét é mon premier doctorant. Je garderai un souvenir imp érissable de notre exp érience, étalonnant mes exigences pour le « malheur » de ses successeurs. Je tiens également à le remercier profond ément pour son amiti é, son soutien et sa pr ésence durant ces ann ées de labeur. Il est un pilier de notre équipe de recherche, initiateur et architecte de nombreuses id ées qui ont contribu é aux travaux de recherche pr ésent és dans ce m émoire. SEBASTIAN RODRIGUEZ est une inspiration pour ses qualit és scientifiques et humaines. Architecte des premiers mod èles holoniques dans notre laboratoire, sans lui, les travaux pr ésent és dans ce m émoire n'auraient pas vu le jour. Je le remercie pour m'avoir permis de d écouvrir sa culture et son pays : l'Argentine. Mon amiti é lui est acquise, ainsi qu' à sa famille. DAVID, DAVY, JOLECYN, MICHA ËL, OLIVIER, PHILIPPE et RENAN sans qui la vie au laboratoire et à l'ext érieur n'aurait pas eu ce « je ne sais quoi » éminemment agr éable et divertissant. N'est-ce pas PHILIPPE ! Merci à ARIANE, CINDY, FABRICE, FRANCK, FR ÉD ÉRICK, GILLIAN, JALIL, PABLO et YASSINE ; nos petites causeries au coin caf é et ailleurs resteront des instants privil égi és. Merci à ANSAR, CHRISTOPHE, LUK, MASSIMO et THOMAS pour nos collaborations et échanges scientifiques vivifiants. Une pens ée pour mon fils ARTHUR, sans qui rien n'aurait ét é possible, pour Ève, source de maintes émotions, ainsi que pour AURORE, CHRISTELLE, DELPHINE, JEAN-CLAUDE, JEAN-FRANC ¸OIS, J ÉR ÔME, JOSETTE, MARIE-CLAUDE et tous mes autres proches, pour leur patience, leur amour et leurs encouragements durant cette derni ère d écennie. Merci infiniment. vii SOMMAIRE xi 6.2 Mod élisation et évaluation d'un r éseau de bus .

Federated simulations address the need for interoperability, as well as the improvement of reuse and composability of existing simulation models. The focal goal in a federated simulation is to facilitate composable simulations by standardizing interfaces to enable at least the technical interoperability among disparate simulations. Yet, existing federated simulation infrastructures neither facilitate sound reasoning about substantive interoperability nor are dynamically extensible. Emergent web services technologies hold out the potential to significantly improve the development of interoperable, extensible, and dynamically composable federations. As such, the recent XMSF initiative urges the use of a set of Web-based technologies that can be applied within an extensible framework for next generation of modeling and simulation applications to interoperate. We discuss how the realization of multimodel and multisimulation formalisms in terms of semantic web and agent technologies may ...

Agent-based simulations and human-subject experiments explore the emergence of respect for property in a specialization and exchange economy with costless theft. Software agents, driven by reciprocity and hill-climbing heuristics and parameterized to replicate humans when property is exogenously protected, are employed to predict human behavior when property can be freely appropriated. Agents do not predict human behavior in a new set of experiments because subjects innovate, constructing a property convention of "mutual taking" in 5 out of the 6 experimental sessions that allows exchange to crowd out theft. When the same convention is made available to agents, they adopt it and again replicate human behavior. Property emerges as a social convention that exploits the capacity for reciprocity to sustain trade.

Traditional (i.e. analytical) modelling practices in the social sciences rely on a very well established, although implicit, methodological protocol, both with respect to the way models are presented and to the kinds of analysis that are performed. Unfortunately, computersimulated models often lack such a reference to an accepted methodological standard. This is one of the main reasons for the scepticism among mainstream social scientists that results in low acceptance of papers with agent-based methodology in the top journals. We identify some methodological pitfalls that, according to us, are common in papers employing agent-based simulations, and propose appropriate solutions. We discuss each issue with reference to a general characterization of dynamic micro models, which encompasses both analytical and simulation models. In the way, we also clarify some confusing terminology. We then propose a three-stage process that could lead to the establishment of methodological standards in social and economic simulations.

We simulate the swarming behavior of three synthetic animal species that differ only by the degree of perception they have on their fellow animals. The species are called mosquitoes, birds and fish. The swarms that comprise many individuals of each species in turn move randomly in a rugged potential landscape. The mosquitoes pay no heed to one another. The birds follow a bunch of their nearest neighbours in front, based on strictly limited visibility. The fish, in turn, sense also far-away neighbors through their lateral line, as modeled by an exponentially decaying perception function. The simulations show that such local differences in perception by swarming individuals have global macroscopic consequences to the geometry of the corresponding swarms. These consequences are of persistent nature across many simulations with each species.

In this comment we discuss the problem of reconciling the linear efficiency of price returns with the long-memory of supply and demand. We present new evidence that shows that efficiency is maintained by a liquidity imbalance that co-moves with the imbalance of buyer vs. seller initiated transactions. For example, during a period where there is an excess of buyer initiated transactions, there is also more liquidity for buy orders than sell orders, so that buy orders generate smaller and less frequent price responses than sell orders. At the moment a buy order is placed the transaction sign imbalance tends to dominate, generating a price impact. However, the liquidity imbalance rapidly increases with time, so that after a small number of time steps it cancels all the inefficiency caused by the transaction sign imbalance, bounding the price impact. While the view presented by Bouchaud et al. of a fixed and temporary bare price impact is self-consistent and formally correct, we argue that viewing this in terms of a variable but permanent price impact provides a simpler and more natural view. This is in the spirit of the original conjecture of Lillo and Farmer, but generalized to allow for finite time lags in the build up of the liquidity imbalance after a transaction. We discuss the possible strategic motivations that give rise to the liquidity imbalance and offer an alternative hypothesis. We also present some results that call into question the statistical significance of large swings in expected price impact at long times.

With support from DMSO, MIT Lincoln Laboratory is developing tools and techniques for measuring and characterizing the performance of HLA federations operating with various RTIs. These tools and techniques are intended for use by federation developers to study, understand, and enhance the performance of their federations. They are intended for application across many types of federations, from time-managed, analysis- oriented federations interested in maximizing the number of executions possible within a fixed time interval to hardware-in-the-loop federations interested in minimizing end-to-end latency. An essential initial step in this effort is the development of instrumentation to capture interactions between the federates and the RTI, as well as data flows among the federates. This paper will describe a generic RTI "wrapper" that can capture call patterns (federate-to-RTI and RTI-to-federate) to generate statistical descriptions of service invocations, including histog...

The purpose of this research is to develop a Class Library in the domain of Scrolling Shooter games. The built of this Class Library will be used to develop Scrolling Shooter games as the result of this research. In software engineering, there is a reuse concept that is used to reuse functional systems. One application of this concept is the class library. With the class library, programmers can directly call the functions they need without building them from scratch. This study also used the class library concept for the domain of the shooter scrolling game case. The development of a Class Library is done through seven phases, Domain Analysis, Frozenspot Analysis, Hotspot Analysis, Modelling Class Library, Implementation Class Library, Unit Testing, and Integration Testing, and those will be the main discussion of this research. Furthermore, this research's conclusion is expected to help game programmers develop Scrolling Shooter games without making the whole system functional...

This article is concerned with a relatively straightforward research question: how do attitudes toward the formerly Thomson Reuter's Impact Factor (IF) affect the reliability of the review process? Consistent with the literature (e.g., Moed & Van Leeuwen 1996;, the angle with which we tackle the issue is the assumption that IF has no relation with the quality of either a journal nor the articles published in it. Given this assumption, we study cognitive and psychological biases (e.g., Gigerenzer & Selten 2001; Kahneman 2003) related to the perception that quality is represented by IF, held by some reviewers. In addition to that we also attempt to understand the influence that reviewers receive from professional academic communities with stronger or weaker conviction on IF as a quality measure. Consistently with a recent article on the perception of scientific value and IF (Secchi & Cowley 2018), we develop an agent-based simulation model to reason on some of the critical aspects of peer review. In the following pages, we introduce a theoretical framework that is rooted in cognitive biases and offer a distributed cognition perspective. We then introduce our simulation model and analyse a selection of results before offering some concluding remarks.

Fire safety in high-rise residential buildings is a complex issue, especially when it comes to electrical shaft fires. These enclosed vertical shafts help the rapid spread of smoke, toxic gases and heat across different floors and pose a high risk to the occupants and affect the evacuation process. However, the actual life fire outbreaks show that the existing measures are still wanting as far as evacuation safety is concerned. These issues are addressed in this research through the use of performance-based fire design (PBFD) to assess fire behaviour and evacuation patterns in high-rise buildings. The study then simulates using PyroSim and Pathfinder simulation software, the visibility of smoke, reduction of visibility, CO and CO2 levels, temperature changes, and congestion of the evacuation corridors. Unlike other studies, this paper combines both fire development and occupants’ response to give a holistic approach to the issue of evacuation challenges. One of the findings of this research is the analysis of the ASET and RSET whereby it was found that the current provisions in fire safety do not ensure a safe exit. It was established that RSET is much higher than ASET, which points to a severe lack in current fire safety solutions. Simulations incorporating NBC-2016 (National Building Code-2016) provisions—such as fire-rated doors, sprinklers, and mechanical ventilation—demonstrate improved outcomes, reducing RSET from 1,272 seconds to 746 seconds. However, persistent challenges such as congestion, bottlenecks, and hazardous gas levels highlight the need for enhanced fire safety strategies. This research offers practical recommendations to improve evacuation effectiveness through better ventilation, compartmentalization, and advanced suppression systems. The findings contribute to risk mitigation strategies, expand the knowledge base for fire safety, and provide a foundation for improving fire safety regulations in high-rise buildings.

The presents a comprehensive legal analysis of child custody determinations in Tanzania, drawing on statutory frameworks, judicial precedents, and procedural considerations. Anchored by the High Court’s reasoning in Karayemaha J and supported by recent case law, the study interrogates how Tanzanian courts balance legal mandates with the evolving principle of the child’s best interests.
It explores the procedural pathways through which custody is contested and resolved, the weight given to the child’s expressed wishes, and the interpretive latitude exercised by judges.

The inclusion of a High Court case study provides a grounded perspective on how abstract legal principles are operationalized in practice. Ultimately, the paper calls for a harmonized custody framework that aligns domestic legal standards with international child rights obligations, ensuring that custody decisions are both legally sound and child-centered.

We present applications of a cellular automaton approach to pedestrian dynamics introduced in [1, 2]. It is shown that the model is able to reproduce collective effects and self-organization phenomena encountered in pedestrian traffic, e.g. lane formation in counterflow through a large corridor and oscillations at doors. Furthermore we present simple examples where the model is applied to the simulation of evacuation processes.

The level of investment in AVs technology has been increasing over the years as both researchers and developers are cooperating with the objective of developing AVs and understanding their behaviors and implications. Despite the enthusiastic speculation about AVs, little is known about the implications of AVs on our lives and the intertwined relationships between the implications. Thus, the main objective of this paper is to reveal the benefits and risks of AVs and sketch out the main trends in this area in order to provide some directions and recommendations for the future. This study focuses on analyzing the impact of AVs on the required fleet size, vehicle utilization, cost of mobility, public transit service, public behavior, transportation network, land use, economy, environment, society, and public health. Furthermore, the paper analyzes the intertwined relationship between the implications of AVs. Additionally, the paper sheds light on the potential benefits and challenges of the deployment of AVs in developing countries. The analysis shows that while AVs offer multiple benefits, they also pose new risks. The degree to which AVs can affect our plant mainly depends on regulatory actions, as the broader implications of AVs are mainly dependent on how the technology will be adopted, which can be controlled by regulatory actions.

Much of the debate about model-based explanations in economics revolves around How-Possibly Explanations (HPEs). HPEs propose a potential way in which something could occur. I argue that these debates often occur without adequately considering the various ways in which economic models can provide How-Actually Explanations (HAEs). HAEs concentrate on what actually happens, providing explanations based on real-world events. I suggest that adopting a pluralistic and pragmatic approach is among the most effective methods for exploring the potential of HAEs in economics. To support my argument, I will use two case studies from microeconomics and macroeconomics. I contend that these case studies provide grounds to believe that a pluralist and pragmatist perspective could clarify how models in economics might offer HAEs.

In the past decades, models such as cellular automata and agentbased systems, as a discretisation of morphogenetic models coming from the fields of biology and chemistry, have been applied to the study of urban form, in order to describe, especially a posteriori, the stochastic geometry underlying cities in different steps of their development. These techniques are at the basis of more recent studies, also involving artificial intelligence in the process. This turns out to have, at least to some extent, a predictive nature: we cannot foretell the exact shape of a city in the future, but we can observe how the variation of some parameters might affect its development, giving rise to a range of different scenarios.

In most cities, taxis play an important role in providing point-to-point transportation service. If the taxi service is reliable, responsive, and cost-effective, past studies show that taxi-like services can be a viable choice in replacing a significant amount of private cars. However, making taxi services efficient is extremely challenging, mainly due to the fact that taxi drivers are self-interested and they operate with only local information. Although past research has demonstrated how recommendation systems could potentially help taxi drivers in improving their performance, most of these efforts are not feasible in practice. This is mostly due to the lack of both the comprehensive data coverage and an efficient recommendation engine that can scale to tens of thousands of drivers. In this paper, we propose a comprehensive working platform called the Driver Guidance System (DGS). With real-time citywide taxi data provided by our collaborator in Singapore, we demonstrate how we ca...

Agent-Based Modelling is gaining wider acceptance as a paradigm for social research. However, it still present limitations in the management of the process to generate the simulations from the initial conceptual models. Thus, it is difficult to reuse the knowledge from available models and adapt it to different hypotheses. This paper proposes the use of metamodels in order to define explicitly the core concepts of a problem and to differentiate the aspects involved in the process. A case study for continuous double auctions shows how to define the related metamodel and use it to address alternative situations in these auctions. The case study drives the discussion on the advantages and limitations that metamodelling can bring to social simulation.

Agent-based simulation is being recognized as a useful tool for the study of social systems. It is based on the idea that agents can be used as a good abstraction of members of a society, and by simulating their interactions, observe the emergent behavior. Usually, agent-based models for social simulation are rather simple, but there are more and more works that try to apply this technique for rather complex systems, both in the typology of the agents and their relationships, and in scalability. For this reason, software engineering techniques are required that would facilitate the development of agent-based simulation systems. In this sense, it can be useful to consider agentoriented methodologies, as they cope with these requirements. This work explores the application of a model-driven methodology for the development of Multi-Agent Systems, INGENIAS. There are several advantages of this approach. One is the possibility to define specific modeling languages that are conceptually close to the domain-expert, in this case for simulation of social systems. This will facilitate the communication of multidisciplinary teams and, by generating code from models, the social scientist is alleviated from the concerns of programming for a simulation platform. This is illustrated with a case study of urban dynamics.

Abstract. Although there are many methodologies for the development of multi-agent systems, these are scarcely applied for agent-based simulation. The different activities for the creation of an agent based model and its simulation for the study of a social system, which include abstraction, design, approximation and coding, are usually performed in a monolithic way. Besides, when several roles take part in this process, communication problems may arise between people with different backgrounds and perspectives. This ...

This paper makes use of spatial agent-based simulation techniques inspired by theoretical condensed matter physics. These techniques form part of 'sociophysics' an approach that has emerged slowly, but with increasing speed, over the last thirty years. This paper reports on two studies by the authors relating to the adoption of new technologies by a stylized virtual community comprising thousands of agents. The first case emphasizes the physics aspects of sociophysics in seeking to assess how a social system responds when confronted with potentially fashionable new technologies. In that example one of two new technologies is visible to neighboring residential agents and complex phenomena are seen to emerge depending upon the initial parameterization of the society. These phenomena are reminiscent of phase transition physics. The second set of examples, while modeled entirely separately, has a similar starting point, but seeks to give its agents a more realistic decision rule. Building upon ideas from marketing and the social sciences the agents in this latter work form their decisions according to Icek Ajzen's 1991 Theory of Planned Behavior. Both sets of simulations reveal lessons of possible benefit to policy-makers concerned with technology adoption. The work reported here uses exemplary scenarios relating to one such area of technology policy -the need for new electricity end-use technologies, which favor significant reductions in greenhouse gas emissions.

OntoUML is a modeling language based on an underlying foundational ontology (UFO). Over the years, it has gained increasing attention in the area of ontology-driven conceptual modeling, becoming one of the most used languages in that field. In this paper, we report on a preliminary prototype that kickstarts the creation of pre-conceptual models in OntoUML from instance-level examples in PURO, a graphical modeling language originally developed for analogously kickstarting OWL ontology skeletons.

Dieses Buch stellt die Weber-De Broglie-Bohm-Theorie (WDBT) vor – eine konsequente Weiterentwicklung etablierter Ansätze, die die Weber-Elektrodynamik (WED) mit der De-Broglie-Bohm-Theorie (DBT) verbindet. Der Kern der WDBT ist radikal einfach: Elektromagnetische Effekte werden nicht durch Felder, sondern durch direkte, geschwindigkeits- und beschleunigungsabhängige Kräfte zwischen Ladungen vermittelt. Kombiniert mit dem nicht-lokalen Quantenpotential der DBT entsteht so ein kohärenter theoretischer Rahmen, der Plasmen, Quantenphänomene und astrophysikalische Prozesse einheitlich erklärt, ohne auf die Ad-hoc-Annahmen klassischer Feldtheorien zurückgreifen zu müssen.

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Organisations in Multi-Agent Systems (MAS) have proven to be successful in regulating agent societies. Nevertheless, changes in agents' behaviour or in the dynamics of the environment may lead to a poor fullment of the system's purposes, and so the entire organisation needs to be adapted. In this paper we focus on endowing the organisation with adaptation capabilities, instead of expecting agents to be capable of adapting the organisation by themselves. We regard this organisational adaptation as an assisting service provided by what we call the Assistance Layer. Our generic Two Level Assisted MAS Architecture (2-LAMA) incorporates such a layer. We empirically evaluate this approach by means of an agent-based simulator we have developed for

Multiple, highly autonomous, satellite systems are envisioned in the near future because they are capable of higher performance, lower cost, better fault tolerance, reconfigurability and upgradability. This paper presents an architecture and multi-agent design and simulation environment that will enable agent-based multi-satellite systems to fulfill their complex mission objectives, termed ObjectAgent TM . Its application is shown for a distributed aperture radar mission, although its applicability spans many types of missions. Required spacecraft functions, software agents, and multi-agent organisations are described for the radar mission, as well as their implementation. Agent-based simulations of mission case studies show the autonomous operation of the multiagent architecture, which can then be used to build, evaluate and compare autonomous software architectures for multiple satellite systems.

Indiscriminate disposal of beverage cans as waste poses a great threat to the environment, causing flooding, landfill, and blockage of drainages, leading to land pollution and sometimes accident. Hence, there is a need to design a system capable of converting these wastes into usable products. In this study, a simulation-based analytical design for aluminum recycling processing plant was carried out to ascertain the efficiency and reliability of the design before fabrication using finite element analysis (FEA) approach. The simulation results revealed a lesser maximum stress of 6.323 MPa for the furnace outer casing under the action of load with a displacement of 0.0795 mm. The stress of the machine components is less than the yield strength of the selected materials, making the machine fit and workable. The analytical results agree with the numerical analysis; hence the conceptual design is fit for fabrication based on the design analysis and evaluation. After the design analysis a...

Japanese government issued the hazardmaps of Tsunami by Great Nankai Trough Earthquake in August of 2012. There are many swimming beaches in Tsunami attacking area.Evacuation plan should be made for beach users because many strangers are there. In this paper, evacuation simulations have been conducted by a multi-agent model to investigate factors for safe evacuation.Walking velocity of users in the sea, on the beach and on the road was used in the simulations. The velocity was figured by using video data of evacuation drill.From the results, it is found that the appropriate setting of guide panels is an important factor for achievement of safe evacuation.

In mobile adhoc networks, mobile node and its movement patterns has significant impact on network protocols & its performance. Therefore, it is required to analyze and understand node mobility specific to scenario such as disaster management, village area network, etc. and or in general. Mobility models are based on setting out different parameters related to node movements. These parameters are the starting location of mobile nodes, their movement direction, velocity range, speed changes over time. Various matrices can be evaluated to the mobility models. This synthetic data can be given as input to suitable network routing protocols for performance analysis. In this paper authors has evaluated performances matrices of various mobility models using MobiSim simulator. Further, levy walk mobility model's metrics are compared with random families, group & geographic models and social model. Our observation results indicate that the levy walk features are important in characterizing the performance of mobile ad hoc network.

Hospitals and clinics are increasingly interested in building partnerships with community-based organizations to address the social determinants of health. Choosing among community-based health programs can be complex given that programs may have different effectiveness levels and implementation costs. This study develops a decision-making model that can be used to evaluate multiple key factors that would be relevant in resource allocation decisions related to a set of community-based health programs. The decision-making model compares community-based health programs by considering funding limitations, program duration, and participant retention until program completion. Specifically, the model allows decision makers to select the optimal mix of community-based health programs based on the profiles of the population given the above constraints. The model can be used to improve resource allocation in communities, ultimately contributing to the long-term goal of strengthening cross-sector partnerships and the integration of services to improve health outcomes.

Supply chain management is a stratagem, which produces the product with right quality, appropriate quantity, in right time and it deliver the exact order quantity to the right person. However, the uncertainty in the real time manufacturing system is unavoidable. Handling of the post disruption and selecting the suitable rescheduling strategies to overcome the disruption are challengeable task. The current paper deals the framework development to manage disruption from the various entities in the house hold goods manufacturing system. Machine breaks down, supply delay, entry of returned goods, rush orders, supply failure, order postponement, order preponement, order cancellation and the entry of the rework are considered as disruption. The objective of the frame work is to meet the delivery schedule under disruption. Key performance indicator for each disruption and monitoring them from each entities are discussed. This systematic frame work escorts to conduct case study by incorporating popular rescheduling strategies.

Cardiovascular disease (CVD) is contributing significantly to rising death rates in the U.S. Furthermore, areas susceptible to natural disasters face more challenges. When a disaster strikes, a part of the population seeks refuge in shelters where access to essential treatments is limited. The limitation of treatments results in a higher mortality rate among individuals with CVD. In response, this research presents an agent-based model to explore the repercussions of CVD patients lacking access to essential treatment. The model is built to represent the potential impact on health outcomes of individuals with CVD conditions that might be relocated to shelters during a hurricane event. The simulation results show an average 14% rise in CVD mortality after hurricane occurrences which approximately represent the rates observed from hurricane events in Texas. The model is an instrument to forecast long-term health outcomes and to plan for public health interventions associated with disaster relief.

Este ensayo propone entender al ecosistema como un fenómeno emergente que surge de la realización de sus posibilidades inherentes a través de la interrelación dinámica entre sus componentes bióticos y abióticos. Se argumenta que el ecosistema no es una suma estática de partes, sino un sistema complejo cuya inteligencia interrelacional emerge de procesos autoorganizados y coemergentes. La noción de posibilidad realizada y emergencia recíproca se discute en el marco de la teoría de sistemas complejos, ecología evolutiva y filosofía de la naturaleza.

In a simulation project, a good conceptual model representation is critical for communicating conceptual models between stakeholders. A conceptual model describes the problem domain and model specifications. The description of the problem domain includes the objectives, inputs, outputs, content, assumptions and simplifications made in the model. The model specifications are used to specify the model's behavior. This article focuses on the representation of the model content (structure, boundary and level of detail) component of an agent-based simulation (ABS) model. For this, we propose the use of Business Process Model and Notation (BPMN) from the Object Management Group. A Web-based visual modeling tool has been developed using JavaScript to demonstrate how BPMN can be used to represent an ABS conceptual model and how the tool translates the conceptual model into code ready for execution using Repast HPC. Conceptual modeling is the process of abstracting a model from a real or proposed system into a conceptual model (Robinson 2010). There is a point in a simulation project where the conceptual modeling process occurs inside an individual modeler's mind. This 'thinking' process includes reflection on how to structure the problem and how the simulation model should be designed to help decision-makers solve the problem to hand, subject to certain constraints. At some point in the simulation project, the conceptual model needs to be communicated to other stakeholders (such as clients, simulation modelers and domain experts). Nance (1994) refers to explicit representation of the conceptual model as the communicative model. The importance of the quality of communication between stakeholders to make a simulation project (Robinson and Pidd 1998) successful makes the role of (explicit) conceptual model representation important. Onggo ( ) classifies methods for conceptual model representation into three categories: textual, pictorial and multi-faceted. It is clear that the definition of a conceptual model must affect its representation. Unfortunately, there is no single accepted definition of what a conceptual model is. Robinson (2010) discusses various conceptual model definitions and concludes that complete consensus is difficult to achieve. This is due partly to the wide range of applications of computer simulation; each application domain may have different characteristics (such as project scale and team size) and requirements (such as the criticality of model reusability). This article uses the conceptual model definition proposed in Robinson (2010), i.e., a "conceptual model is a non-software specific description of the computer simulation model (that will be, is or has been developed), describing the objectives, inputs, outputs, content, assumptions and simplifications of the model." Based on the separation between domain-oriented components and design-oriented components in a conceptual model, as proposed in , we extend Robinson's definition to include design-oriented components. These provide a representation of the problem domain which is consistent with

A hard problem facing interdisciplinary scientific collaboration is communicating across disciplines. We examine this challenge using the case of a project building models by merging social science and complexity science expertise. We discuss how divergent epistemic practices between demography and complexity science affect this collaboration. We focus on significant conceptual barriers to combining demographic methods with complexity science simulation techniques. Even though both disciplines claim expertise in ‘modelling’ social systems, there is a significant divergence between considering models as a means of theory-formation and models as a means of prediction. This creates a communication gap between demographic and complexity-science portions of the project, overcoming which demands re-interpreting and re-positioning one’s practice on subjects even as simple as what a ‘model’ is (or what it is for). This seems to us an instance of a deep and important philosophical problem. I...

This paper presents an agent-based model of fixed-term academic employment in a competitive research funding environment based on UK academia. The goal of the model is to investigate the effects of job insecurity on research productivity. Agents may be either established academics who may apply for grants, or postdoctoral researchers who are unable to apply for grants and experience hardship when reaching the end of their fixed-term contracts. Model results show that in general adding fixed-term postdocs to the system produces less total research output than adding half as many permanent academics. An in-depth sensitivity analysis is performed across postdoc scenarios, and indicates that promoting more postdocs into permanent positions produces significant increases in research output.

Novelty detection allows robots to recognise unexpected data in their sensory field and can thus be utilised in applications such as reconnaissance, surveillance, self-monitoring, etc. We assess the suitability of Grow When Required Neural Networks (GWRNNs) for detecting novel features in a robot's visual input in the

The paper investigates the role of progressive income taxation in the frame of the basic multiplier-accelerator model in continuous time. It is shown that, while the proportional taxation is, as common wisdom believes, always stabilizing, in the case of non-linear progressive ...

L. Fanti Department of Economics, University of Pisa, Via Cosimo Ridolfi, 10, I-56124 Pisa (PI), Italy e-mail: lfanti@ec.unipi.it; tel.: +39 050 22 16 369; fax: +39 050 22 16 384 L. Gori (Corresponding author) Department of Economics, University of Pisa, Via Cosimo Ridolfi, 10, I-56124 Pisa ...

Socio-Ecological Systems (SESs) are the systems in which our everyday lives are embedded, so understanding them is important. The complex properties of such systems make modelling an indispensable tool for their description and analysis. Human actors play a pivotal role in SESs, but their interactions with each other and their environment are often underrepresented in SES modelling. We argue that more attention should be given to social aspects in models of SESs, but this entails additional kinds of complexity. Modelling choices need to be as transparent as possible, and to be based on analysis of the purposes and limitations of modelling. We recommend thinking in terms of modelling projects rather than single models. Such a project may involve multiple models adopting different modelling methods. We argue that agent-based models (ABMs) are an essential tool in an SES modelling project, but their expressivity, which is their major advantage, also produces problems with model transparency and validation. We propose the use of formal ontologies to make the structure and meaning of models as explicit as possible, facilitating model design, implementation, assessment, comparison and extension.

Agent-based models (ABMs) have become a valuable tool in social epistemology for addressing a fundamental question: How should scientists communicate? Yet, ABMs often yield conflicting results-some suggest that high levels of communication decrease group accuracy, while others find it beneficial. Why do models differ so dramatically? We argue that these discrepancies arise from a simple fact: different models use different conceptions of "communication," and model qualitatively different phenomena. To demonstrate the effects of such differences, we integrate three paradigmatic conceptions of communication from the literature-direct evidence sharing, belief averaging, and testimony exchange-into a unifying simulation. This allows us to test them under identical conditions. Our findings suggest that communication is generally beneficial. However, the effects of communication vary significantly by which conception one adopts, even under identical conditions. This lack of robustness highlights a critical issue: outcomes depend heavily on how communication is modeled.

What is the rational response to a scientific disagreement? Many epistemologists argue that disagreement with an epistemic peer should generally lead to conciliation by lowering confidence in the disputed belief or even suspending judgment altogether. Although this conciliatory approach is widely regarded as a norm of individual rationality, its value in the context of collective scientific inquiry is less clear. Some have even raised concerns that conciliating in scientific disagreements may slow progress or reduce the efficiency of inquiry. In this article, we introduce a novel agent-based model that captures key aspects of scientific disagreement by incorporating both epistemic norms, which govern belief revision, and zetetic norms, which guide how scientists pursue inquiry. Our results indicate that the effects of conciliating in the face of disagreement-whether detrimental or beneficial-depend on the zetetic norms that scientists follow. When scientists focus on exploiting the hypothesis that they believe is most likely to succeed, remaining steadfast is more effective. However, with exploratory scientists, conciliation does not negatively affect group performance. These findings highlight the critical role of zetetic norms in determining the rational response to disagreement in scientific practice.

A methodology is presented for real-time control of unmanned aerial vehicles (UAV) in the absence of apriori knowledge of location of sites in an inhospitable flight territory. Our proposed hostile control methodology generates a sequence of waypoints to be pursued on the way to the target. Waypoints are continually computed with new information about the nature of changing threat. The