Publications (64)0 Total impact
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ABSTRACT: Reasoning about agents that we observe in the world is challeng-ing. Our available information is often limited to observations of the agent's external behavior in the past and present. To under-stand these actions, we need to deduce the agent's internal state, which includes not only rational elements (such as intentions and plans), but also emotive ones (such as fear). In addition, we often want to predict the agent's future actions, which are constrained not only by these inward characteristics, but also by the dynamics of the agent's interaction with its environment. BEE (Behavior Evolution and Extrapolation) uses a faster-than-real-time agent-based model of the environment to characterize agents' internal state by evolution against observed behavior, and then predict their future behavior, taking into account the dynamics of their interaction with the environment.
04/2007;
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ABSTRACT: In recent years, mobile ad-hoc networks (MANETs) have been deployed in various scenarios, but their scalability is severely restricted by the human operators' ability to configure and manage the network in the face of rapid change of the network structure and demand patterns. In this paper, we present a self-organizing approach to MANET management that follows general principles of engineering swarming applications.
02/2004;
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ABSTRACT: ce such environment and be influenced by it. ii. openness: software systems will be subject to decentralized management and will dynamically change their structure: new components can be dynamically created or destroyed and, via mobility, will be able, to roam in and out the permeable boundaries of different software systems. Thus, the problem of openness is currently much broader than being simply a problem of interoperability; iii. locality in control: the components of software systems will represent autonomous loci of control. In fact, most components of software systems will be active, and will have local control over their activities, although will be in need of coordinating these activities with other active components. iv. locality in interactions: despite living in a fully connected world, software components interact with each other accordingly to local (geographical or logical) patterns. In other words, systems will have to be modeled around clusters of locally interactin
02/2004;
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ABSTRACT: In this paper, we identify and analyze a set of characteristics that increasingly distinguish today's complex software systems from "traditional" ones. Several examples in different areas show that these characteristics are not limited to a few application domains but are widespread. Then, we discuss how these characteristics are likely to impact dramatically the very way software systems are modeled and engineered. In particular, we appear to be on the edge of a radical shift of paradigm, about to change our very attitudes in software systems modeling and engineering. Keywords: Distributed Systems, Design Paradigms, Multiagent Systems. To be published in: The Knowledge Engineering Review Corresponding Author: Franco Zambonelli 2 1
02/2004;
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ABSTRACT: A helpful abstraction of a group of agents is a set of interacting roles, or sets of normative behaviors, that the agents can assume. An important characteristic of real-world agent systems is that the roles played by an agent may change over time. These changes can be of several different kinds. We describe an illustrative application where such role changes are important, analyze and classify the various kinds of role changes over time that may occur, and show how this analysis is useful in developing a more formal description of the application.
05/2003;
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ABSTRACT: The emerging science of simulation enables us to explore the dynamics of large and complex systems even if a formal representation and analysis of the system is intractable and a construction of a real-world instantiation for the purpose of experimentation is too expensive. A computer simulation model can be run for many more configurations and the accumulated observations deepen our understanding of the system's operation, but it is very important that we have tools that help us manage the huge numbers of experiments that need to be run and the massive data sets that are collected. Furthermore, as we explore vast parameter spaces of simulation model, we need guidance in finding regions of interest in a resource efficient way.
05/2003;
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ABSTRACT: Large systems of agents deployed in a real-world environment face threats to their problem solving performance that are independent of the complexity of the problem or the characteristics of their specific solution mechanism. One such threat is the degrading of the quality of agent coordination mechanisms when faced with delays in the flow of critical information among the agents introduced by communication latencies. In this paper we demonstrate in a simple model of locally interacting agents that the emerging system-level performance may degrade very suddenly as the rate of individual decision making increases against the availability of up-to-date information. We present results from extensive simulation experiments that lead us to select a locally accessible metric to adapt the agent's individual decision rate to values that are below this phase change. Given the generic nature of the coordination mechanism that is analyzed and the informationtheoretic metric, the adaptation mechanism may increase the deployability of large-scale agent systems in real-world applications. Keywords Multi-Agent Coordination, Emergent Phase Structure, Adaptation and Learning, Simulation Experiments, Tools and Methods.
05/2003;
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ABSTRACT: From a software engineering perspective, agent systems are a specialization of object-oriented (OO) systems, in which individual objects have their own threads of control and their own goals or sense of purpose.
02/2003;
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ABSTRACT: Agents guided by synthetic pheromones can imitate the dynamics of insects. These systems are well suited to problems such as the control of unmanned robotic vehicles. We have developed a model for controlling robotic vehicles in combat missions using synthetic pheromones. In the course of our experimentation, we have identified the need for proper tuning of the algorithms to get acceptable performance. We describe pheromones in natural and synthetic systems, and describe the mechanisms we have developed. The role of evolutionary computing in offline and online tuning is discussed.
02/2003;
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ABSTRACT: Agent-based systems are no longer contained within the boundaries of a single, small agent organization. To meet the demands of large-scale system implementations, agent organizations must deal with environmental forces, interact with other agent organizations, and know how they affect individual agents. In this paper, we look to social and organizational systems theory as a source of inspiration. Many of these techniques have been successful for a hundreds and thousands of years. We believe that the designers of agent-based systems can learn a great deal from organization designers. In the first of a series, this paper examines the notion of role and its implications on how agents might behave in group settings.
02/2003;
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ABSTRACT: Multi-agent systems are particularly appropriate for resource allocation, but configuring them for efficient operation requires understanding their dynamics. Concepts from statistical physics, such as phase transitions, can help. In decision problems such as constraint satisfaction, such transitions exhibit an easy-hard-easy effort profile, so that highly overconstrained problems are easier to solve than those near the transition. The conventional wisdom is that the profile in optimization problems such as resource allocation is monotonic, becoming more difficult as constraints increase.
10/2002;
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ABSTRACT: lVlost 'rame-based knowledge representation (KR) systems have two strange features. First, [he concepts represented by t, he nodes are nouns rather than verbs. Verbal ideas tend to appear mostly in describing roles or slots. Thus the systems are a.symrr,etric. Second, and more seriously, the slot names on f,rames are arbitrary and not deIqned in the system. Usually no metasystem is given to account for them. Thus the systems are not closed.
07/2002;
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ABSTRACT: Much of the power of hypermedia comes from the development of techniques for information management that closely match natural cognitive processes. HyperSet, a hypermedia environment tailored for taxonomic reasoning [Parunak 91], is an example of this philosophy. People perform taxonomic reasoning when they classify, store, and retrieve a number of similar information objects (such as biological specimens, or linguistic constructions, or research projects). The process is essentially set-based. The user sorts objects into sets based on their characteristics; looks together at members of a single set to search for correlations or discernible subsets among them; examines the different sets of which one item is a member to see whether there are relations among them; and generates new sets from old ones.
06/2002;
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ABSTRACT: This paper illustrates the need for altemafive models by exhibiting a particular reasoning task for which navigating among nodes by way of explicit links is less effective than an alternative model of intersecting sets of nodes. The task is taxonomic reasoning, a particular kind of reasoning task that deals with the comparison and classification of highly similar nodes, in which an analyst viewing one node thinks not in terms of linking it to another node, but of including it in or excluding it from a set of related nodes
06/2002;
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ABSTRACT: Discussions of agent interactions frequently characterize behavior as Coherent, collaborative, cooperative, competitive, or coordinated. We propose a series of formal distinctions among these terms and several others. We argue that all of these are specializations of the more foundational category of correlation, which can be measured by the joint information of a system. We also propose congruence as a category orthogonal to the others, reflecting the degree to which correlation and its specializations satisfy user requirements. Then we explore the degree to which lack of correlation can arise purposefully, and show the need to use formal stochasticity in cases where such lack of correlation is truly necessary (such as in stochastic search). Keywords Coordination, correlation, competition, contention, cooperation, congruence, communication, command, constraint, construction, conversation, stigmergy, agent interaction 1.
06/2002;
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ABSTRACT: Several characteristics distinguish today's complex software systems from "traditional" ones. Examples in different areas show that these characteristics, already the focus of agent-oriented software engineering research, influence many application domains. These characteristics will impact how software systems are modeled and engineered.
05/2002;
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ABSTRACT: Agents guided by synthetic pheromones can imitate the behavior of insects in tasks such as path planning. These systems are well suited to problems such as path planning for unmanned robotic vehicles. We have developed a model for controlling robotic vehicles in combat missions using synthetic pheromones. In the course of our experimentation, we have identified the need for proper tuning of the algorithms to get the desired behavior. We briefly describe the synthetic pheromone mechanisms for dynamically finding targets and planning safe paths. Genetic algorithms for automatically tuning the behavior of the pheromone equations are described.
04/2002;
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ABSTRACT: Agents guided by synthetic pheromones can imitate the stigmergetic dynamics of insects. The resulting software architecture is well suited to problems such as the control of unmanned robotic vehicles. We introduce the approach, describe the mechanisms we have developed, and summarize the technology's performance in a series of scenarios reflecting military command and control.
04/2002;
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ABSTRACT: Swarming agents in networks of physically distributed processing nodes may be used for data acquisition, data fusion, and control applications. We present an architecture for active surveillance systems in which simple mo-bile agents collectively process real-time data from heterogeneous sources at or near the origin of the data. We motivate the system requirements with the needs of a surveillance system for the early detection of large-scale bioterrorist attacks on a civilian population, but the same architecture is applicable to a wide range of other domains. The pattern detection and classification processes executed by the proposed sys-tem emerge from the coordinated activities of agents of two populations in a shared computational environment. Detector agents draw each other's attention to significant spatio-temporal patterns in the observed data stream. Classifier agents rank the detected patterns according to their respective criterion. The re-sulting system-level behavior is adaptive, robust, and scalable.
04/2002;
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ABSTRACT: Without an environment, an agent is effectively useless. Cut off from the rest of its world, the agent can neither sense nor act. An environment provides the conditions under which an entity (agent or object) can exist. It defines the properties of the world in which an agent will function. Designing effective agents requires careful consideration of both the physical and communicational aspects of their environment. Two issues exists for understanding environments: 1. Every agent has an environment, no matter what the agent's philosophy or architecture is. 2. Being aware of the agent's environment enables its designer to get more powerful interaction via architecture-dependent means. 1.
01/2002;
