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In recent years, there has been a growing need for active systems that can react automatically to events. Some events are generated externally and deliver data across distributed systems, while others are materialized by the active system itself. Event materialization is hampered by uncertainty that may be attributed to unreliable data sources and networks,(More)
In recent years, there has been an increased need for the use of active systems-systems required to act automatically based on events, or changes in the environment. Such systems span many areas, from active databases , through applications that drive the core business processes of today's enterprises. However, in many cases, the events to which the system(More)
A central challenge in the runtime management of computing environments is the necessity to keep these environments continuously optimized. In this paper we introduce a new paradigm, which focuses on self-optimization according to high-level business objectives such as maximizing revenues. It replaces the more traditional optimizations that are based upon(More)
— A quick recognition of security hazards is challenging. Information sources are often insuffcient to infer the occurrence of hazards with certainty, requiring recognition to be based on patterns of occurrences distributed over space and time. We introduce a generic framework that supports a quick response to changes in patterns of occurrences, using(More)
We propose to improve the efficiency of simulation optimization by integrating the notion of optimal computing budget allocation into the Cross-Entropy (CE) method, which is a global optimization search approach that iteratively updates a parameterized distribution from which candidate solutions are generated. This article focuses on continuous optimization(More)
The Emergency Department (ED) of a modern hospital is a highly complex system that gives rise to numerous managerial challenges. It spans the full spectrum of operational, clinical, and financial perspectives, over varying horizons: operational—a few hours or days ahead; tactical—weeks or a few months ahead; and strategic, which involves(More)