Recent work has demonstrated that several trust and reputation models can be exploited by malicious agents with cyclical behaviour. In each cycle, the malicious agent with cyclical behaviour first regains a high trust value after a number of cooperations and then abuses its gained trust by engaging in a bad transaction. Using a game theoretic formulation, Salehi-Abari and White have proposed the AER model that is resistant to exploitation by cyclical behaviour. Their simulation results imply that FIRE, Regret, and a model due to Yu and Singh, can always be exploited with an appropriate value for the period of cyclical behaviour. Furthermore, their results demonstrate that this is not so for the proposed adaptive scheme. This paper provides a mathematical analysis of the properties of five trust models when faced with cyclical behaviour of malicious agents. Three main results are proven. First, malicious agents can always select a cycle period that allows them to exploit the four models of FIRE, Regret, Probabilistic models, and Yu and Singh indefinitely. Second, malicious agents cannot select a single, finite cycle period that allows them to exploit the AER model forever. Finally, the number of cooperations required to achieve a given trust value increases monotonically with each cycle. In addition to the mathematical analysis, this paper empirically shows how malicious agents can use the theorems proven in this paper to mount efficient attacks on trust models.

Creating artificial intelligent agents that are high-fidelity simulations of natural agents will require the engagement of behavioral scientists. However, agent programming systems that are accessible to behavioral scientists are too limited to create rich agents, and systems for creating rich agents are accessible mainly to computer scientists, not behavioral scientists. We are solving this problem by engaging behavioral scientists in the design of a programming language, and integrating reinforcement learning into the programming language. This strategy will help our language achieve adaptivity, modularity, and, most importantly, accessibility to behavioral scientists. In addition to allowing behavioral scientist to write rich agent programs, our language — AFABL (A Friendly Behavior Language) — will enable a true discipline of modular agent software engineering with broad implications for games, interactive storytelling, and social simulations.

The Embodied Conversational Agents (ECAs) are computergenerated motivation for the study of ECAs, inside PRAIA project, characters whose purpose is to exhibit the same started with the belief that ECAs represent a promising solution properties as humans in face-to-face conversation. The general for responding appropriately to student's in educational goal of researchers in the field of ECAs is to create environments. This work, however, cannot be placed inside agents that can be more natural, believable and easy to use. the "task and Application domains" concentration of the taxonomy Due to the broad scope of research and the multidisciplinary presented above. We are not interested in designing of the field, many other investigations can arise in many different and implementing an ECA to meet the needs and fill a suitable areas, leading researchers to face numerous questions: role within one specific educational environment. We What kind of embodiment to use? What parts of the body to believe that making a general contribution in other concentrations represent? What kind of modalities to explore? What personality will increase the possibilities of future research inside model to consider? Will the ECA have emotions?

In online, dynamic environments, the service requested by consumers may not be readily served by the producers. This requires the consumers and producers to negotiate on the content of the service. To automate this process, agents play a key role in e-commerce. As far as the agents' negotiation strategies are concerned, understanding and reasoning on their users' preferences are important to generate the right offers on behalf of their users. Besides taking other participant's needs into account is important to be able to negotiate effectively. However, preferences of participants are almost always private. The best that can happen is that participants may learn each other's preferences through interactions over time. As agents learn each other's preferences, they can provide better-targeted offers and thus enable faster negotiation. My research direction involves representing and reasoning on preferences, and learning preferences though interaction in automated negotiation.

This My thesis work combines AI, programming language design, incompleteness of perception and dynamism in the environment and software engineering. I am integrating reinforcement creates a strong need for adaptivity. Programming this learning (RL) into a programming language so adaptivity by hand in a language that does not provide builtin that the language achieves three primary goals: accessibility, support for adaptivity is very cumbersome. As I demonstrated adaptivity, and modularity. If I am successful, my or designer specifies the structure of certain parts work will enable a discipline of modular large-scale agent of a program while leaving other portions unspecified, such software engineering while making advanced agent modeling that a learning system can learn how to perform them.

My thesis investigates fault tolerance for cooperative agent systems that have some equivalent of self-replication and self-death. Utilizing biologically-inspired mechanisms, I increase multi-agent system robustness for faulty agents when it is unknown exactly which agent is malfunctioning. It is important to determine new ways to increase robustness of a system, as otherwise it cannot be guaranteed to function in all situations and thus cannot be relied upon. Robustness of a system allows agents to recover from errors and thus function continuously, an increasingly important trait as agent systems are deployed in real world scenarios such as sensor networks or surveillance systems where faulty or malicious nodes could disrupt application performance. To achieve robustness, there must either be prevention of all errors, or a technique for recovering from errors after they have occurred. My thesis creates a new fault tolerance mechanism inspired by cancer biology to remove faulty agents, and then re-applies the developed technique to study the removal of biological cancer cells in simulation.

A metareasoning problem involves three parts: 1) a set of concrete problem domains; 2) reasoners to reason about the problems; and, 3) metareasoners to reason about the reasoners. We believe that the metareasoning community would benefit from agreeing on the first two problems. To support this kind of collaboration, we offer an open source 3D simulator containing everyday, commonsense problems that take place in kitchens. This paper presents several arguments for using a simulator to solve commonsense problems. The paper concludes by describing future work in simulator-based unified generative benchmarks for AI.

Many approaches were explored in recent years to introduce principles of metacognition and meta-learning into cognitive architectures, yet none of them resulted in a scalable human-like learner. This work presents an approach intended to fill the gap between human self-regulated learners and artificial learners by introducing a new spin of the familiar core cognitive architecture paradigm, taking it to a meta-level. The resultant architecture enables in artifacts exclusively human higher cognitive and learning abilities: specifically, deliberative new knowledge construction. Model predictions agree with results of a pilot study with human subjects.

We present a game-theoretic model that formalizes core ideas of conversational grounding theory. This game-theoretic model is based on the concept of signaling games, originally proposed as a model of linguistic convention. We extend signaling games with an observation model, which allows for the possibility that the actions a dialog participant takes may only be partially observable to others. We then apply this model to the domain of referential communication tasks, a type of task commonly used in psycholinguistic experiments.

We study the problem of achieving cooperation between two self-interested agents that play a sequence of randomly generated normal form games, each game played only once. To achieve cooperation we extend a model used to explain cooperative behavior by humans. We show how a modification of a pre-regularized particle filter can be used to detect the cooperation level of the opponent and play accordingly. We examine how properties of the games affect the ability of an agent to detect cooperation and explore the effects of different environments and different levels of conflict. We present results obtained in simulation on hundreds of randomly generated games.