Agent architectures need to organize themselves and adapt dynamically to changing circumstances w... more Agent architectures need to organize themselves and adapt dynamically to changing circumstances without top-down control from a system operator. Some researchers provide this capability with complex agents that emulate human intelligence and reason explicitly about their coordination, reintroducing many of the problems of complex system design and implementation that motivated increasing software localization in the first place. Naturally occurring systems of simple agents (such as populations of insects or other animals) suggest that this retreat is not necessary. This paper summarizes several studies of such systems, and derives from them a set of general principles that artificial multiagent systems can use to support overall system behavior significantly more complex than the behavior of the individuals agents. ([WHUQDO /RFDO /RFDO /RFDO :KDW GRHV D XQLW GR ZKHQ LW UXQV" 6WDWH ([WHUQDO ([WHUQDO /RFDO /RFDO :KHQ GRHV D XQLW UXQ" ([WHUQDO ([WHUQDO FDOOHG
When the same people interact frequently, they come to think alike, a phenomenon we call "collect... more When the same people interact frequently, they come to think alike, a phenomenon we call "collective cognitive convergence" (C 3 ). We discuss instances and practical consequences of this phenomenon; review previous work in sociology, computational social science, and evolutionary biology that sheds light on C 3 ; define a computational model and metrics for the convergence process; report on experiments with this model and metrics; and suggest how insights from the model can help manage C 3 .
Proceedings of the fourth international conference on Autonomous agents, 2000
In many applied domains such as military operations, manufacturing, and logistics, entities chang... more In many applied domains such as military operations, manufacturing, and logistics, entities change location under constraints. The centralized control mechanisms traditionally used for these problems can become bottlenecks and points of vulnerability. Multi-agent negotiation schemes enable the entities to maintain the desired constraints among themselves in decentralized fashion. This paper explores a particularly simple form of coordination that replaces central coordination and agentto-agent communication with interaction through a shared environment. Inspired by pheromones in insect populations, this method can solve the classical Missionaries and Cannibals problem. We illustrate how agents can be programmed to interact using synthetic pheromones, and evaluate the performance of our algorithms for four different levels of pheromone information and two different approaches to constructing the functions by which agents respond to the pheromones.
Proceedings of the second international joint conference on Autonomous agents and multiagent systems, 2003
The emerging science of simulation enables us to explore the dynamics of large and complex system... more 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. In this paper we use a model of agent-based graph coloring to introduce a software infrastructure for the systematic execution of experiments across large regions of parameter space (parameter sweep). Furthermore, we present a multi-agent system that searches large parameter spaces automatically for regions of interest specified by a fitness function. The fitness function captures the researcher's interest in certain system dynamics. We specify a function that searches for overlap regions that accompany phase changes in the simulation model. The agents search the parameter space by executing simulation experiments in regions of high fitness. As a consequence, the use of computational resources is minimized.
Proceedings of the fourth international joint conference on Autonomous agents and multiagent systems, 2005
Many multi-agent systems seek to reconcile two apparently inconsistent constraints. The system's ... more Many multi-agent systems seek to reconcile two apparently inconsistent constraints. The system's overall objective is defined at a global level. However, the agents have only local information available to them in selecting their actions. Such systems are presently more art than science. They often exhibit regularities (such as exponential convergence) that we do not understand, and we do not know how to improve their functioning in a disciplined manner. In this paper, we develop a simple statistical model for such systems that can enhance both our intuitions about their functioning and our ability to engineer them, and apply it to three systems that have been constructed.
Hierarchical clustering is used widely to organize data and search for patterns. Previous algorit... more Hierarchical clustering is used widely to organize data and search for patterns. Previous algorithms assume that the body of data being clustered is fixed while the algorithm runs, and use centralized data representations that make it difficult to scale the process by distributing it across multiple processors. Self-Organizing Data and Search (SODAS), inspired by the decentralized algorithms that ants use to sort their nests, relaxes these constraints. SODAS can maintain a hierarchical structure over a continuously changing collection of leaves, requiring only local computations at the nodes of the hierarchy and thus permitting the system to scale arbitrarily by distributing nodes (and their processing) across multiple computers.
International Journal of Cooperative Information Systems, 2000
Agent technologies have steadily matured in moving from the research laboratory to industrial app... more Agent technologies have steadily matured in moving from the research laboratory to industrial application over the last ten years. Numerous systems have been deployed or are under advanced development with strong industrial support. These systems suggest important lessons for both industry and researchers. From an industrial perspective, these examples reflect trends in both business and technology that make agents an increasingly attractive commercial tool. From a research perspective, these examples identify important gaps in agent technology that merit the attention of academicians.
First International Conference on Self-Adaptive and Self-Organizing Systems (SASO 2007), 2007
In current information systems, information is passive. People act upon it, either sending it to ... more In current information systems, information is passive. People act upon it, either sending it to known destinations or pulling it from known sources. InformANTS makes information active, enabling it to move actively from one user to another. This paper introduces the InformANTS vision and describes one of its major system components, the Information Matching System. Particular emphasis is placed on the distinctive self-organizing processes from which emerge the information exploration and exploitation capabilities of InformANTS.
When a set of people interact frequently with one another, they often grow to think more and more... more When a set of people interact frequently with one another, they often grow to think more and more along the same lines, a phenomenon we call "collective cognitive convergence" (C 3 ). We discuss instances of C 3 and why it is advantageous or disadvantageous; review previous work in sociology, computational social science, and evolutionary biology that sheds light on C 3 ; define a computational model for the convergence process and quantitative metrics that can be used to study it; report on experiments with this model and metric; and suggest how the insights from this model can inspire techniques for managing C 3 .
Modern UAV's reduce the threat to human operators, but do not decrease the manpower requirements.... more Modern UAV's reduce the threat to human operators, but do not decrease the manpower requirements. Each aircraft requires a flight crew of one to three, so deploying large numbers of UAV's requires committing and coordinating many human warfighters. Insects perform impressive feats of coordination without direct inter-agent coordination, by sensing and depositing pheromones (chemical scent markers) in the environment . We have developed a novel technology for coordinating the movements of multiple UAV's based on a computational analog of pheromone dynamics. The control logic is simple enough that it can be executed autonomously by a UAV, enabling a single human to monitor an entire swarm of UAV's. This paper describes the technology, its application to UAV coordination, and the results we have obtained. Effective command and control for swarming UAV's has four requirements, which can be summarized as four D's: Diverse, Distributed, Decentralized, and Dynamic. Diverse.-A system to control swarming UAV's must be diverse in several ways. It must integrate diverse functions, including communications among the UAV's, command oversight, and information management to enable the UAV's to make reasonable decisions. It must handle information of diverse kinds, including imagery, vibration, chem/bio, ELINT, etc. This information may concern diverse entities, including a heterogeneous population of unmanned vehicles (air and ground), targets to be approached, threats to be avoided, and the presence of other friendly units with which coordination is required. It may also come from diverse sources, including local ground sensors, information from other nearby friendly units, and far-distant intelligence (e.g., national assets). Distributed.-The US military is facing a serious shortfall in long-range communications bandwidth . Warfighters cannot assume the availability of unlimited satcom channels. This limitation can be addressed by distributing the C 2 system physically over the battlespace. Distribution helps lower bandwidth in two ways.
Software Engineering for Large-Scale Multi-Agent Systems, 2003
Agent-based systems are no longer contained within the boundaries of a single, small agent organi... more 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.
Without an environment, an agent is effectively useless. Cut off from the rest of its world, the ... more 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.
Multi-agent systems are an attractive approach to modeling systems of interacting entities, but i... more Multi-agent systems are an attractive approach to modeling systems of interacting entities, but in some cases mathematical models of these systems can offer complementary benefits. We report a case study of how the two modeling methods can profitably engage one another. The system we study (12) is an agent-based simulation of how groups of interacting entities can come to think alike. Though formal analysis of most of the models in that paper is intractable, a mean field analysis can be performed for the simplest case. On the one hand, while the formal analysis captures some of the basic features of that model, other features remain analytically elusive, reinforcing the benefits of agent- based over equation-based modeling. On the other hand, the mathematical analysis draws our attention to certain interesting features of the model that we might not have considered if we had not performed it. Responsible modeling of a domain should include both approaches.
In this paper, we identify and analyse a set of characteristics that increasingly distinguish tod... more In this paper, we identify and analyse 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 on the very way software systems are modelled and engineered. In particular, we appear to be on the edge of a radical shift of paradigm, which is about to change our very attitudes in software systems modelling and engineering.
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