DYNAMIC RISK MANAGEMENT-SYSTEMS - HYBRID ARCHITECTURE AND OFFSHORE PLATFORM ILLUSTRATION

This paper describes and illustrates the architecture of computer-base d Dynamic Risk Management Systems (DRMS) designed to assist real-time risk management decisions for complex physical systems, for example, e ngineered systems such as offshore platforms or medical systems such a s patient treatment in Intensive Care Units. A key characteristic of t he DRMSs that we describe is that they are hybrid, combining the power s of Probabilistic Risk Analysis methods and heuristic Artificial Inte lligence techniques. A control module determines whether the situation corresponds to a specific rule or regulation, and is clear enough or urgent enough for an expert system to make an immediate recommendation without further analysis of the risks involved. Alternatively, if tim e permits and if the uncertainties justify it, a risk and decision ana lysis module formulates and evaluates options, including that of gathe ring further information. This feature is particularly critical since, most of the time, the physical system is only partially observable, i .e., the signals observed may not permit unambiguous characterization of its state. The DRMS structure is also dynamic in that, for a given time window (e.g., 1 day or 1 hour), it anticipates the physical syste m's state (and, when appropriate, performs a risk analysis) accounting for its evolution, its mode of operations, the predicted external loa ds and problems, and the possible changes in the set of available opti ons. Therefore, we specifically address the Issue of dynamic informati on gathering for decisionmaking purposes. The concepts are illustrated focusing on the risk and decision analysis modules for a particular c ase of real-time risk management on board offshore oil platforms, name ly of two types of gas compressor leaks, one progressive and one catas trophic. We describe briefly the DRMS proof-of-concept produced at Sta nford, and the prototype (ARMS) that is being constructed by Bureau Ve ritas (Paris) based on these concepts.