Jordi Sabater-Mir

• PhD
• Spanish National Research Council

When people need help with day-to-day tasks they turn to family, friends or neighbours to help them out. Finding someone to help out can be a stressful waste of time. Despite an increasingly networked world, technology falls short in combating such daily irritations. uHelp provides a platform for building a community of helpful people and supports...

Humans possess innate collaborative capacities. However, effective teamwork often remains challenging. This study delves into the feasibility of collaboration within teams of rational, self-interested agents who engage in teamwork without the obligation to contribute. Drawing from psychological and game theoretical frameworks, we formalise teamwork...

We formalise human teamwork in tasks involving judgment as a public goods game. Our focus is on tasks where members’ contributions are combined through weighted averaging, such as brain-storming. Using a multiagent system, we examine the alignment between learned agent strategies and Nash Equilibria. Overall, our results demonstrate that our multia...

We present a novel model for studying group performance in collaborative multiagent teams. The model incorporates task interdependence and evaluation types as key factors influencing group dynamics. We propose a simulation game called CollabQuest, which will serve as a platform to explore the effects of these factors on collective performance withi...

When people need help with their day-to-day activities, they turn to family, friends or neighbours. But despite an increasingly networked world, technology falls short in finding suitable volunteers. In this paper, we propose uHelp, a platform for building a community of helpful people and supporting community members find the appropriate help with...

Probabilistic models of competence assessment join the benefits of automation with human judgment. We start this paper by replicating two preexisting probabilistic models of peer assessment (PG1-bias and PAAS). Despite the use that both make of probability theory, the approach of these models is radically different. While PG1-bias is purely Bayesia...

principles that should govern autonomous AI systems. It essentially states that a system's goals and behaviour should be aligned with human values. But how to ensure value alignment? In this paper we first provide a formal model to represent values through preferences and ways to compute value aggregations; i.e. preferences with respect to a group...

We present an agent-based model of paper publication and consumption that allows to study the effect of two different evaluation mechanisms, peer review and reputation, on the quality of the manuscripts accessed by a scientific community. The model was empirically calibrated on two data sets, mono- and multi-disciplinary. Our results point out that...

We explore a means to understand second order emergent social phenomena (EP2), that is, phenomena that involve groups of agents who reason and decide, specifically, about actions – theirs or others’ – that may affect the social environment where they interact with other agents. We propose to model such phenomena as socio-cognitive technical systems...

We study how communication affects cooperation in an experimental public goods environment with punishment and counter-punishment opportunities. Participants interacted over 30 rounds in fixed groups with fixed identifiers that allowed them to trace other group members' behavior over time. The two dimensions of communication we study are asking for...

In the seminal work 'An Evolutionary Approach to Norms', Axelrod identified internalization as one of the key mechanisms that supports the spreading and stabilization of norms. But how does this process work? This paper advocates a rich cognitive model of different types, degrees and factors of norm internalization. Rather than a none-or-all phenom...

Punishment plays a crucial role in favoring and maintaining social order. Recent studies emphasize the effect of the norm-signaling function of punishment. However, very little attention has been paid so far to the potential of group punishment. We claim that when inflicted by an entire group, the recipient of punishment views it as expressing norm...

Agreement Technologies are needed for autonomous agents to come to mutually acceptable agreements, typically on behalf of humans. These tec hnologies include trust computing, negotiation, argumentation and semantic alignment. In this paper, we identify a number of open questions regarding the integration of computational models and tools for trust...

In open multiagent systems, agents depend on reputation and trust mechanisms to evaluate the behavior of potential partners. Often these evaluations are associated with a measure of reliability that the source agent computes. However, due to the subjectivity of reputation-related information, this can lead to serious problems when considering commu...

Material punishment has been suggested to play a key role in sustaining human cooperation. Experimental findings, however, show that inflicting mere material costs does not always increase cooperation and may even have detrimental effects. Indeed, ethnographic evidence suggests that the most typical punishing strategies in human ecologies (e.g., go...

Punishment intensity in the Experiments with Human Subjects depending on punished subject’s contribution minus that of punisher. (TIF)

Average required contribution in tokens over rounds 11–20 in the Experiments with Human Subjects. (TIF)

Percentages of the three verbal messages sent in the message and sanction treatment over rounds 11–20 in the Experiments with Human Subjects. (TIF)

Amount of punishments, sanctions and messages sent in the Agent Based simulation. (TIF)

Determinants of punishment levels in the punishment and sanction treatments in the Experiments with Human Subjects: random-effects tobit regressions. (TIFF)

Determinants of suggested contributions in the message and sanction treatments in the Experiments with Human Subjects: random-effects tobit regressions. (TIFF)

Percentage of individuals that sent a message over rounds 11–20 in the Experiments with Human Subjects. (TIF)

Dynamics of the Individual and Normative Drives in the Agent Based Model. (TIF)

Mean Cooperation along the simulation experiment contrasted with the value of the Forgetting Probability. (TIF)

Determinants of punishment levels in the sanction treatment in the Experiments with Human Subjects: random-effects tobit regressions. (TIFF)

Average Payoffs along the Agent Based simulation. (TIF)

Mean Cooperation along the simulation experiment contrasted with the value of the Initial Punishment Probability. (TIF)

Mean Cooperation along the simulation experiment contrasted with the value of the Individual Weight. (TIF)

Supporting Information Document. (DOC)

Norm Salience Mechanism in the Agent Based Model: Cues and Weights. (TIFF)

When people need help with day-to-day tasks they turn to family, friends or neighbours to help them out. Despite an increasingly networked world, technology falls short in supporting such daily tasks. u-Help provides a platform for building a community of helpful people and supports them in finding volunteers for day-to-day tasks. It relies on thre...

Convention emergence solves the problem of choosing, in a decentralized way and among all equally beneficial conventions, the same convention for the entire population in the system for their own benefit. Our previous work has shown that reaching 100% agreement is not as straighforward as assumed by previous researchers, that, in order to sa...

Trust models as thus far described in the literature can be seen as a monolithic structure: a trust model is provided with a variety of inputs and the model performs calculations, resulting in a trust evaluation as output. The agent has no direct method of adapting its trust model to its needs in a given context. In this article, we propose a first...

The notion of Multi-Agent System environment is currently considered as a mediating entity, functioning as enabler but possibly also as a manager and constrainer of agent actions, perceptions, and interactions. In this paper, we analyze how the environment could be a first class abstraction to support the building, the development and the managemen...

In this chapter we discuss the ways in which trust can be combined with argumentation. This is a new field of research that is showing promising approaches to a number of problems in both argumentation and trust. We discuss three ways in which trust and argumentation are combined. The first is to use the trustworthiness of an agent as a level of co...

In this paper we propose the use of a cognitive architecture as a mechanism to improve the level of personalization in a recommen- dation process. The main idea is to use the cognitive architecture as an advisor that lies between the user and a set of specialized recommenders. The cognitive architecture should know about the strengths and weak- nes...

We describe the problems and issues that have emerged during the development of an application using multiagent systems to test a hypothesis about the development and impact of social norms that affect the reproduction of small scale hunter-gatherer societies.

El uso de simulación de agentes dirigida en arqueología tiene, relativamente, una larga tradición. Sin embargo, estas simulaciones han estado orientadas, principalmente, a estudiar los procesos espaciales y la gestión de los recursos y sistemáticamente han hecho caso omiso de un aspecto esencial de toda sociedad: el uso de las normas sociales e ins...

http://ceur-ws.org/Vol-918/111110260.pdf

“Social norms” is a term widely used in different areas of research like sociology, philosophy or multiagent systems. However, there is still not a clear definition of what social norms are and the types of problems they solve. This work presents a general classification and distinction of norms from a game theoretical perspective. The types of nor...

Recent studies show that punishment plays a crucial role in favoring and maintaining social order. However, very little attention has been paid so far to the potential of distributed punishment. In this work we put forward the hypothesis that distributed punishment is more effective than individual punishment, because is more persuasive in conveyin...

Agents in open multi-agent systems must deal with the difficult problem of selecting interaction partners in the face of uncertainty about their behaviour. This is especially problematic if they have to interact with an agent they have not interacted with before. In this case they can turn to their peers for information about this potential partner...

In open multi-agent systems trust models are an important tool for agents to achieve effective interactions. However, in these kinds of open systems, the agents do not necessarily use the same, or even similar, trust models, leading to semantic differences between trust evaluations in the different agents. Hence, to successfully use communicated tr...

The execution of process models is usually presented through a graphical user interface, especially when users' input is required. Existing mechanisms, such as Electronic Institutions (EIs), provide means to easily specify and automatically execute process models. However, every time the specification is modified, the graphical user interface (GUI)...

Computational trust and reputation models have been recognized as one of the key technologies required to design and implement agent systems. These models manage and aggregate the information needed by agents to efficiently perform partner selection in uncertain situations. For simple applications, a game theoretical approach similar to that used...

In open environments, agents depend on reputation and trust mechanisms to evaluate the behavior of potential partners. The scientific research in this field has considerably increased, and in fact, reputation and trust mechanisms have been already considered a key elements in the design of multi-agent systems. In this paper we provide a survey that...

This book constitutes the refereed proceedings of the 12th International Workshop on Multi-Agent-Based Simulation, MABS 2011, held in Taipei, Taiwan, in May 2011. The 10 revised selected and extended papers presented were carefully reviewed and selected from 21 submissions. The topics covered are MABS in scientometrics; MABS in politics, transit an...

Social conventions are useful self-sustaining protocols for groups to coordinate behavior without a centralized entity enforcing coordination. The emergence of such conventions in different multi agent network topologies has been investigated by several researchers, although exploring only specific cases of the convention emergence process. In this...

In open multi-agent systems trust is necessary to improve cooperation by enabling agents to choose good partners. Most trust models work by taking, in addition to direct experiences, other agents' communicated evaluations into account. However, in an open multi-agent system other agents may use different trust models and as such the evaluations the...

This paper presents a simulation of research behaviour, focusing on the process of writing papers, submitting them to journals and conferences, reviewing them, and accepting/rejecting them. The simulation is currently used to evaluate the OpinioNet reputation model, which calculates the reputation of researchers and research work based on the propa...

In this paper we have compared two independent models implemented to analyze the eects of social information transmission. The rst of them, Repage, is centered on an articulated theory of social evaluations. The second system, that has been developed in NetLogo, follows the same specications of the Repage model but with several simplications. We im...

As explained by Axelrod in his seminal work An Evolutionary Approach to Norms, punishment is a key mechanism to achieve the necessary social control and to impose social norms in a self-regulated society. In this paper, we distinguish between two enforcing mechanisms. i.e. punishment and sanction, focusing on the specific ways in which they favor t...

In heterogeneous multi-agent systems trust is necessary to improve interactions by enabling agents to choose good partners. Most trust models work by taking, in addition to direct experiences, other agents' communicated evaluations into account. However, in an open MAS other agents may use different trust models and the evaluations they communicate...

In this paper we present the notion of Social Instruments as a set of mechanisms that facilitate the emergence of norms from repeated interactions between members of a society. Specifically, we focus on two social instruments: rewiring and observation. Our main goal is to provide agents with tools that allow them to leverage their social network of...

In open multiagent systems, agents depend on reputation and trust mechanisms to evaluate the behavior of potential partners. Often these evaluations (social evaluate) are associated with a measure of reliability that the source agent computes. When considering communicated social evaluations, this may lead to serious problems due to the subjectivit...

Trust and reputation measures are crucial in distributed open systems where agents need to decide whom or what to choose. Existing work has overlooked the impact of an entity's position in its structural graph and its effect on the propagation of trust in such graphs. This paper presents an algorithm for the propagation of rep- utation in structura...

Open multiagent systems are systems populated with autonomous agents whose intentions are unknown. Due to this uncertainty, reputation mechanisms arise as a key technology when designing such systems. These mechanisms endow agents with the capability to reason about the behaviour of their potential partners regarding certain criteria, for instance,...

In open multi-agent systems trust models are an important tool for agents to achieve effective interactions. However, the agents do not necessarily use similar trust models, leading to semantic differences between trust evaluations in the different agents. We show how to form a trust alignment by considering the interactions agents share. We descri...

RESUMEN el uso de simulación de agentes dirigida en arqueología tiene, relativamente, una larga tra-dición. sin embargo, estas simulaciones han estado orientadas, principalmente, a estudiar los procesos espaciales y la gestión de los recursos y sistemáticamente han hecho caso omiso de un aspecto esencial de toda sociedad: el uso de las normas socia...

This paper proposes a new paradigm for dealing with scientific knowl-edge in general, and publications in particular. The paradigm aims at changing the way in which knowledge is produced, disseminated, evaluated, and consumed. A formal model is proposed and the issues of credit attribution, copyrights and licensing, which are crucial for the succes...

The Internet-of-Services describes a general paradigm of distributed computing with transparent service selection in a shared infrastructure. One particular question to be solved is how to match service supply and demand dynamically, while information is asymmetrically distributed between buyers and sellers (represented by agents). As buyers can no...

Reputation mechanisms have been recognized one of the key technologies when designing multi-agent systems. They are specially relevant in complex open environments, becoming a non-centralized mechanism to control interactions among agents. Cognitive agents tackling such complex societies must use reputation information not only for selecting partne...

This paper examines the decentralized recognition of groups within a multiagent normative society in dynamic environments. In our case, a social group is defined based on the set of social norms used by its members. These social norms regulate interactions under certain situations, and situations are determined by the environmental conditions. Envi...

Social conventions are useful self-sustaining protocols for groups to coordinate behavior without a centralized entity enforcing coordination. The emergence of such conventions in different multi agent network topologies has been investigated by several researchers. In the literature we can observe two different approaches taken by agents to reach...

We present a mathematical framework for communicating about trust in terms of interactions. We argue that sharing an ontology about trust is not enough and that interactions are the building blocks that all trust-and reputation models use to form their evaluations. Thus, a way of talking about these interactions is essential to gossiping in open he...

Abstract—Social conventions,are useful self-sustaining proto- cols for groups,to coordinate,behavior,without,a centralized entity enforcing,coordination. We perform,an,in-depth study of different network structures, to compare and evaluate the effects of different network,topologies on the success and rate of emergence,of social conventions. While...

In this paper we present an application build on top of electronic institutions in order to create a remote experimental platform for human and virtual agents. Our software objectives are twofold: (1) provide experiment designers with a tool to design an experiment where human and virtual agents will interact, and, (2) provide experimental subjects...

This paper examines the decentralized recognition of groups within a multiagent normative society. In this work we explore different mechanisms that allow agents to recognize the others as members of a certain social group. Considering as the basic mechanism the one that makes agents interact with other agents without considering the previous inter...

Computational trust and reputation models have been rec- ognized as one of the key technologies required to design and implement agent systems. These models manage and aggre- gate the information needed by agents to efficiently perform partner selection in uncertain situations. For simple appli- cations, a game theoretical approach similar to that...

Knowing which agents to trust is an important problem in open multi-agent systems. A way to help solve this prob-lem is by allowing agents to relay information about trust to each other. We argue trust is a subjective phenomenon and therefore needs aligning. We present a mathematical framework for communicating about trust in terms of inter-actions...

The Agent Reputation and Trust (ART) Testbed initiative was launched with the goal of establishing a testbed for agent reputation-and trust-related technologies. This initiative has lead to the delivery of a flexible/modular prototype platform to the community. After two years and four successful competitions, several issues have arisen that requir...

Reputation is a fundamental instrument of partner selection. Developed within the domain of electronic auctions, reputation technology is being been imported by other applications, from social networks to institutional evaluation. Its impact on trust enforcement is uncontroversial and its management is of primary concern for entrepreneurs and other...

Social Norms proliferate in societies as a mechanism for self-organization. This kind of norms are not enforced by a central authority and the individuals of the society are those responsible for their generation and maintenance. The maintenance process is what is known as norm support and is supported by several mechanisms like for example laws, s...

Since electronic and open environments became a reality, computational trust and reputation models have attracted increasing interest in the field of multi- agent systems (MAS). Some of them are based on cognitive theories of reputation that require cognitive agents to display all their potential. One of them is Repage, a computational system based...

Abstract Our main interest research is focused on reaching a decentral- ized form of social order through the usage of social norms in virtual communities. In this paper, we analyze the effects of different sets of social norms within a society. The simulation scenario used for the experiments is a metaphor,of a resource- gatherer prehistoric socie...

This paper examines the decentralized formation of groups within a multiagent normative society. In our case, a group is defined based on the set of social norms used by its members: all the agents using the same set of norms belong to the same social group. In this pa-per we explore different mechanisms that allow agents to recognize the others as...

Social Norms proliferate in societies as a mechanism for self-organi-zation. This kind of norms are not enforced by a central authority and the indi-viduals of the society are those responsible for their generation and maintenance. The maintenance process is what is known as norm support and is supported by several mechanisms like for example laws,...

Since electronic and open environments became a reality, computa-tional trust and reputation models have attracted increasing interest in the field of multi-agent systems (MAS). Some of them are based on cognitive theories and require cognitive agents to display all their potential. However, none of them have yet shown a full integration with real...

Our main interest research is focused on reaching a decentralized form of social order through the usage of social norms in virtual communities. In this paper, we analyze the effects of different sets of social norms within a society. The simulation scenario used for the experiments is a metaphor of a resource-gatherer prehistoric society. Finally,...

This book constitutes the thoroughly refereed post-workshop proceedings of the 11th International Workshop on Trust in Agent Societies, TRUST 2008, held in Estoril, Portugal, in the context of AAMAS 2008, the main international conference on autonomous agents and multi-agent systems. The 17 revised full papers presented were carefully reviewed and...

Interest for computational trust and reputation models is on the rise. One of the most important aspects of these models is how they deal with information received from other individuals. More generally, the critical choice is how to represent and how to aggregate social evaluations. In this article, we make an analysis of the current approaches of...

Since electronic and open environments became a reality, computational models of trust and reputation have attracted increasing interest in the field of multi-agent systems (MAS). In virtual societies of human actors very well-known mechanisms are already used to control non normative agents, for instance, the eBay scoring system. In virtual societ...

In this work we present a mechanism designed for the selection of a suitable set of social norms that would reg-ulate a simulated virtual society. The approach taken for this selection problem is a combination of Genetic algorithms and Simulation. A resource-gathering soci-ety has been built using Repast, and on top of it, the genetic algorithm tha...

In an unpredictable, heterogeneous world, intelligent agents depend on accurate social information; reputation, among the preemi- nent artifacts to transmit social evaluations, has been receiving growing attention by social scientists. A realistic description of reputation must include inaccurate information; in this paper, based on the distinction...

The Agent Reputation and Trust (ART) Testbed initiative was launched with the goal of establishing a testbed for agent reputation-and trust-related technologies. This initiative has lead to the delivery of a flexible/modular prototype platform to the community. After two years and four successful competitions, several issues have arisen that requir...