The defence landscape is populated by multiple information sources and consumers. The information sources must correlate and combine their information in order to derive accurate situation awareness. This motivates information fusion solutions. The information consumers must be proactive in seeking relevant information and managing their joint decisions in response to the information. This motivates an agent-based approach. The need for accurate and timely situation awareness drives decisions about where to gather new information. This is fused with previous information and the fused products influence future decisions, creating a feedback loop. Agent-based information fusion (ABIF) is the result of combining information fusion and agent-based methods in order to control multiple such feedback loops executing within a large-scale system. The desired effect of ABIF is to drive positive emergent behaviours that increase the operational effectiveness of the system. This paper describes the modern defence landscape and states its main requirements for ABIF solutions. Core functionality is indicated in relation to specific defence application examples. Then the paper highlights two case studies in the areas of situation awareness and resource management. The first demonstrates how information fusion techniques developed in the ALADDIN project can be used to ensure robust estimation in sensor fusion networks when some of the sensor data may be biased and faulty. The second study demonstrates that decentralized agent-based solutions for resource management outperform a distributed (i.e. replicated central) solution when the communication networks are sparse and subject to delays.

This paper proposes and evaluates a framework for cooperative control of a multi-agent system. The framework is evaluated on a target-tracking application where a distributed sensor network is tasked to autonomously observe targets within the environment. The problem of cooperative control is defined using two distinct levels of cooperation: implicit and explicit. Implicit cooperation is defined as cooperation through only the exchange of environmental data to compile a common picture over which to reason locally. For example, in this paper, decentralized data fusion algorithms are used to build and update a common picture of the target positions and velocities. Explicit cooperation, which is the main focus of this paper, negotiates the agents explicitly on a joint set of actions to perform. In this paper, the problem of explicit cooperation is formulated as a distributed optimization, and a framework to find the joint set of actions is proposed. The framework utilizes two algorithms, the Max-Sum algorithm, to globally solve a factorizable utility function, and Probability Collectives (PC), to solve the individual factors of the utility function. The paper presents experimental results of the two algorithms using a simulated distributed sensor network when the tracking problem is and is not factorizable. The results show that the proposed framework can efficiently and effectively enable cooperation in a distributed sensor network. The Max-Sum algorithm provides a distributed and flexible approach to solve a factorizable utility function, where the PC algorithm was shown to efficiently solve the individual factors when more than four sensors are required to cooperate.

We investigate the assignment of assets to tasks where each asset can potentially execute any of the tasks, but assets execute tasks with a probabilistic outcome of success. There is a cost associated with each possible assignment of an asset to a task, and if a task is not executed, there is also a cost associated with the non-execution of the task. Thus, any assignment of assets to tasks will result in an expected overall cost which we wish to minimize. We formulate the allocation of assets to tasks in order to minimize this expected cost, as a nonlinear combinatorial optimization problem. A neural network approach for its approximate solution is proposed based on selecting parameters of a random neural network (RNN), solving the network in equilibrium, and then identifying the assignment by selecting the neurons whose probability of being active is the highest. Evaluations of the proposed approach are conducted by comparison with the optimum (enumerative) solution as well as with a greedy approach over a large number of randomly generated test cases. The evaluation indicates that the proposed RNN-based algorithm is better in terms of performance than the greedy heuristic, consistently achieving on average results within 5% of the cost obtained by the optimal solution for all problem cases considered. The RNN-based approach is fast and is of low polynomial complexity in the size of the problem, while it can be used for decentralized decision making.

Sensor management in information-rich and dynamic environments can be posed as a sequential action selection problem with side information. To study such problems we employ the dynamic multi-armed bandit with covariates framework. In this generalization of the multi-armed bandit, the expected rewards are time-varying linear functions of the covariate vector. The learning goal is to associate the covariate with the optimal action at each instance, essentially learning to partition the covariate space adaptively. Applications of sensor management are frequently in environments in which the precise nature of the dynamics is unknown. In such settings, the sensor manager tracks the evolving environment by observing only the covariates and the consequences of the selected actions. This creates difficulties not encountered in static problems, and changes the exploitation–exploration dilemma. We study the relationship between the different factors of the problem and provide interesting insights. The impact of the environment dynamics on the action selection problem is influenced by the covariate dimensionality. We present the surprising result that strategies that perform very little or no exploration perform surprisingly well in dynamic environments.

MOTIVATION: CORBA (Common Object Request Broker Architecture), as an open standard, is considered to be a good solution for the development and deployment of applications in distributed heterogeneous environments. This technology can be applied in the bioinformatics area to enhance utilization, management and interoperation between biological resources. RESULTS: This paper investigates issues in developing CORBA applications for genome mapping information systems in the Internet environment with emphasis on database connectivity and graphical user interfaces. The design and implementation of a CORBA prototype for an animal genome mapping database are described. AVAILABILITY: The prototype demonstration is available via: http://www.ri.bbsrc.ac.uk/ark_corba/. CONTACT: [email protected]