scholarly journals Simulating hidden dynamics : Introducing Agent-Based Models as a tool for linkage analysis

2020 ◽  
Vol 2 (1) ◽  
pp. 1-33
Author(s):  
Martin Wettstein
Keyword(s):  
Linkage Analysis ◽  
Media Effects ◽  
Measurement Errors ◽  
Explanatory Power ◽  
Opinion Dynamics ◽  
Field Conditions ◽  
Panel Surveys ◽  
Agent Based ◽  
Linkage Analyses ◽  
Promising Tool

Abstract Linkage analyses use data from panel surveys and content analyses to assess media effects under field conditions and are able to close the gap between experimental and survey-based media effects research. Results from current studies and simulations indicate, however, that these studies systematically under-estimate real media effects as they aggregate measurement errors and reduce the complexity of media content. In response to these issues, we propose a new method for linkage analysis which applies agent-based simulations to directly assess short-term media effects using empirical data as guideposts. Results from an example study modeling opinion dynamics in the run-up of a Swiss referendum show that this method outperforms traditional regression-based linkage analyses in detail and explanatory power. In spite of the time-consuming modeling and computation process, this approach is a promising tool to study individual media effects under field conditions.

scholarly journals Simulating Hidden Dynamics. Introducing Agent-Based Models as a tool for linkage analysis

2019 ◽  
Author(s):  
Martin Wettstein
Keyword(s):  
Linkage Analysis ◽  
Media Effects ◽  
Measurement Errors ◽  
Explanatory Power ◽  
Opinion Dynamics ◽  
Field Conditions ◽  
Panel Surveys ◽  
Agent Based ◽  
Linkage Analyses ◽  
Promising Tool

Linkage analyses use data from panel surveys and content analyses to assess media effects under field conditions and are able to close the gap between experimental and survey-based media effects research. Results from current studies and simulations indicate, however, that these studies systematically under-estimate real media effects as they aggregate measurement errors and reduce the complexity of media content. In response to these issues, we propose a new method for linkage analysis which applies agent-based simulations to directly assess short-term media effects using empirical data as guideposts.Results from an example study modeling opinion dynamics in the run-up of a Swiss referendum show that this method outperforms traditional regression-based linkage analyses in detail and explanatory power. In spite of the time-consuming modeling and computation process, this approach is a promising tool to study individual media effects under field conditions.

scholarly journals Equity Effects of Congestion Charges: An Exploratory Analysis with MATSim

2017 ◽  
Vol 2670 (1) ◽  
pp. 75-82 ◽  
Author(s):  
Lucas Meyer de Freitas ◽  
Oliver Schuemperlin ◽  
Milos Balac ◽  
Francesco Ciari
Keyword(s):  
Travel Time ◽  
Large Scale ◽  
Agent Based ◽  
Promising Tool ◽  
Travel Time Savings ◽  
Time Savings ◽  
Time Changes ◽  
High Level ◽  
Congestion Charging ◽  
Equity Effects

This paper shows an application of the multiagent, activity-based transport simulation MATSim to evaluate equity effects of a congestion charging scheme. A cordon pricing scheme was set up for a scenario of the city of Zurich, Switzerland, to conduct such an analysis. Equity is one of the most important barriers toward the implementation of a congestion charging system. After the challenges posed by equity evaluations are examined, it is shown that agent-based simulations with heterogeneous values of time allow for an increased level of detail in such evaluations. Such detail is achieved through a high level of disaggregation and with a 24-h simulation period. An important difference from traditional large-scale models is the low degree of correlation between travel time savings and welfare change. While traditional equity analysis is based on travel time savings, MATSim shows that choice dimensions not included in traditional models, such as departure time changes, can also play an important role in equity effects. The analysis of the results in light of evidence from the literature shows that agent-based models are a promising tool to conduct more complete equity evaluations not only of congestion charges but also of transport policies in general.

scholarly journals Modeling Confirmation Bias and Peer Pressure in Opinion Dynamics

2021 ◽  
Vol 9 ◽  
Author(s):  
Longzhao Liu ◽  
Xin Wang ◽  
Xuyang Chen ◽  
Shaoting Tang ◽  
Zhiming Zheng
Keyword(s):  
Public Opinion ◽  
Large Scale ◽  
Confirmation Bias ◽  
Opinion Dynamics ◽  
Peer Pressure ◽  
Homogeneous Population ◽  
Agent Based ◽  
Collective Decisions ◽  
Personal Opinion ◽  
The Impact

Confirmation bias and peer pressure are regarded as the main psychology origins of personal opinion adjustment. Each show substantial impacts on the formation of collective decisions. Nevertheless, few attempts have been made to study how the interplay between these two mechanisms affects public opinion evolution on large-scale social networks. In this paper, we propose an agent-based model of opinion dynamics which incorporates the conjugate effect of confirmation bias (characterized by the population identity scope and initiative adaptation speed) and peer pressure (described by a susceptibility threshold and passive adaptation speed). First, a counterintuitive non-monotonous phenomenon arises in the homogeneous population: the number of opinion clusters first increases and then decreases to one as the population identity scope becomes larger. We then consider heterogeneous populations where “impressionable” individuals with large susceptibility to peer pressure and “confident” individuals with small susceptibility coexist. We find that even a small fraction of impressionable individuals could help eliminate public polarization when population identity scope is relatively large. In particular, the impact of impressionable agents would be greater if these agents are hubs. More intriguingly, while impressionable individuals have randomly distributed initial opinions, most of them would finally evolve to moderates. We highlight the emergence of these “impressionable moderates” who are easily influenced, yet are important in public opinion competition, which may inspire efficient strategies in winning competitive campaigns.

scholarly journals Paths to Polarization: How Extreme Views, Miscommunication, and Random Chance Drive Opinion Dynamics

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
Matthew A. Turner ◽  
Paul E. Smaldino
Keyword(s):  
Opinion Dynamics ◽  
Initial Distribution ◽  
Polarization Measurement ◽  
Cultural Complexity ◽  
Stochastic Variation ◽  
Social Phenomena ◽  
Agent Based ◽  
The Social ◽  
Apparent Reduction ◽  
Path Dependent

Understanding the social conditions that tend to increase or decrease polarization is important for many reasons. We study a network-structured agent-based model of opinion dynamics, extending a model previously introduced by Flache and Macy (2011), who found that polarization appeared to increase with the introduction of long-range ties but decrease with the number of salient opinions, which they called the population’s “cultural complexity.” We find the following. First, polarization is strongly path dependent and sensitive to stochastic variation. Second, polarization depends strongly on the initial distribution of opinions in the population. In the absence of extremists, polarization may be mitigated. Third, noisy communication can drive a population toward more extreme opinions and even cause acute polarization. Finally, the apparent reduction in polarization under increased “cultural complexity” arises via a particular property of the polarization measurement, under which a population containing a wider diversity of extreme views is deemed less polarized. This work has implications for understanding the population dynamics of beliefs, opinions, and polarization as well as broader implications for the analysis of agent-based models of social phenomena.

scholarly journals Encoding Theory of Mind in Character Design for Pedagogical Interactive Narrative

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Mei Si ◽  
Stacy C. Marsella
Keyword(s):  
Theory Of Mind ◽  
User Interaction ◽  
Interactive Narrative ◽  
Agent Based ◽  
Promising Tool ◽  
Interactive Narratives ◽  
Computer Aided ◽  
Character Design

Computer aided interactive narrative allows people to participate actively in a dynamically unfolding story, by playing a character or by exerting directorial control. Because of its potential for providing interesting stories as well as allowing user interaction, interactive narrative has been recognized as a promising tool for providing both education and entertainment. This paper discusses the challenges in creating interactive narratives for pedagogical applications and how the challenges can be addressed by using agent-based technologies. We argue that a rich model of characters and in particular a Theory of Mind capacity are needed. The character architect in the Thespian framework for interactive narrative is presented as an example of how decision-theoretic agents can be used for encoding Theory of Mind and for creating pedagogical interactive narratives.

A spatially explicit agent-based model of central place foraging theory and its explanatory power for hunter-gatherers settlement patterns formation processes

2020 ◽  
Vol 28 (5) ◽  
pp. 377-397 ◽  
Author(s):  
Kaarel Sikk ◽  
Geoffrey Caruso
Keyword(s):  
Settlement Patterns ◽  
Spatial Configuration ◽  
Explanatory Power ◽  
Central Place ◽  
Spatially Explicit ◽  
Formation Processes ◽  
Central Place Foraging ◽  
Hunter Gatherers ◽  
Agent Based ◽  
Settlement Location

The behavioural ecological approach to anthropology states that the density and distribution of resources determines optimal patterns of resource use and also sets its constraints to grouping, mobility and settlement choice. Central place foraging (CPF) models have been used for analyzing foraging behaviours of hunter-gatherers and drawing a causal link from the volume of available resources in the environment to the mobility decisions of hunter-gatherers. In this study, we propose a spatially explicit agent-based CPF model. We explore its potential for explaining the formation of settlement patterns and test its robustness to the configuration of space. Building on a model assuming homogeneous energy distributions, we had to add several new parameters and an adaptation mechanism for foragers to predict the length of their stay, together with a heterogeneous environment configuration. The validation of the model shows that the spatially explicit CPF is generally robust to spatial configuration of energy resources. The total volume of energy has a significant effect on constraining sedentism as predicted by aspatial model and thus can be used on different environmental conditions. Still the spatial autocorrelation of resource distribution has a linear effect on optimal mobility decisions and needs to be considered in predictive models. The effect on settlement location choice is not substantial and is more determined by other characteristics of settlement location. This limits the CPF models in analyzing settlement pattern formation processes.

INFLUENCE OF COLLABORATIVE BEHAVIOR ON CLAIM NEGOTIATION

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Rita Awwad ◽  
Stephanie Atallah ◽  
Carol Menassa
Keyword(s):  
Dispute Resolution ◽  
Construction Projects ◽  
Opinion Dynamics ◽  
Negotiation Process ◽  
Project Delivery ◽  
Integrated Project Delivery ◽  
Agent Based ◽  
Construction Disputes ◽  
Collaborative Behavior ◽  
Integrated Project

The high cost incurred by the resolution of conflicts is largely affected by the existing adversarial nature of the construction industry along with the use of non-efficient dispute resolution methods in construction projects. This paper studies opinion dynamics in the negotiation of construction disputes while trying to understand the behavior and extremism of each contractual party. The developed model uses an agent-based approach to show how each agent’s attitude can influence the negotiation process when solving a dispute. It can also be used to highlight the importance of alternative dispute resolution (ADR) methods and the use of a mediator in helping parties initiate negotiation and decrease the number of negotiation cycles needed to converge. The results showed that negotiation is not only affected by the attitude and character of the agents involved but it is also influenced by the delivery method of the project and the level of intensity of each agent. It was found that when the project is delivered through an Integrated Project Delivery (IPD) method, parties are more flexible and cooperative and will reach agreement within few negotiation cycles.

scholarly journals Shadowing and shielding: Effective heuristics for continuous influence maximisation in the voting dynamics

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0252515
Author(s):  
Guillermo Romero Moreno ◽  
Sukankana Chakraborty ◽  
Markus Brede
Keyword(s):  
Political Competition ◽  
Explanatory Power ◽  
Opinion Dynamics ◽  
Fixed Number ◽  
Pure Nash Equilibrium ◽  
Information Campaigns ◽  
Continuous Regime ◽  
Optimal Allocations ◽  
Game Theoretic ◽  
Continuous Strategies

Influence maximisation, or how to affect the intrinsic opinion dynamics of a social group, is relevant for many applications, such as information campaigns, political competition, or marketing. Previous literature on influence maximisation has mostly explored discrete allocations of influence, i.e. optimally choosing a finite fixed number of nodes to target. Here, we study the generalised problem of continuous influence maximisation where nodes can be targeted with flexible intensity. We focus on optimal influence allocations against a passive opponent and compare the structure of the solutions in the continuous and discrete regimes. We find that, whereas hub allocations play a central role in explaining optimal allocations in the discrete regime, their explanatory power is strongly reduced in the continuous regime. Instead, we find that optimal continuous strategies are very well described by two other patterns: (i) targeting the same nodes as the opponent (shadowing) and (ii) targeting direct neighbours of the opponent (shielding). Finally, we investigate the game-theoretic scenario of two active opponents and show that the unique pure Nash equilibrium is to target all nodes equally. These results expose fundamental differences in the solutions to discrete and continuous regimes and provide novel effective heuristics for continuous influence maximisation.

scholarly journals Graphene Oxide-Gold Nanorods Nanocomposite-Porphyrin Conjugate as Promising Tool for Cancer Phototherapy Performance

2021 ◽  
Vol 14 (12) ◽  
pp. 1295
Author(s):  
Thabang Calvin Lebepe ◽  
Sundararajan Parani ◽  
Vuyelwa Ncapayi ◽  
Rodney Maluleke ◽  
Grace It Mwad Mbaz ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Gold Nanorods ◽  
Therapeutic Agent ◽  
High Heat ◽  
Therapeutic Agents ◽  
Water Soluble ◽  
Structural And Optical Properties ◽  
Cancer Treatments ◽  
Agent Based ◽  
Promising Tool

The cancer mortality rate has increased, and conventional cancer treatments are known for having many side effects. Therefore, it is imperative to find a new therapeutic agent or modify the existing therapeutic agents for better performance and efficiency. Herein, a synergetic phototherapeutic agent based on a combination of photothermal and photodynamic therapy is proposed. The phototherapeutic agent consists of water-soluble cationic porphyrin (5,10,15,20-tetrakis(N-methylpyridinium-3-yl)porphyrin, TMePyP), and gold nanorods (AuNRs) anchored on graphene-oxide (GO) sheet. The TMePyP was initially synthesized by Adler method, followed by methylation, while GO and AuNRs were synthesized using Hummer’s and seed-mediated methods, respectively. The structural and optical properties of TMePyP were confirmed using UV-Vis, zeta analyzer, PL, FTIR and NMR. The formation of both GO and AuNRs was confirmed by UV-Vis-NIR, FTIR, TEM and zeta analyzer. TMePyP and AuNRs were anchored on GO to form GO@AuNRs-TMePyP nanocomposite. The as-synthesized nanocomposite was stable in RPMI and PBS medium, and, on irradiation, produced high heat than the bare AuNRs, with high photothermal efficiency. In addition, the nanocomposite produced higher singlet oxygen than TMePyP with high biocompatibility in the absence of light. These results indicated that the as-synthesized nanocomposite is a promising dual photodynamic and photothermal agent for cancer therapy.

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