Knowledge Representation Concepts for Automated SLA Management

Outsourcing of complex IT infrastructure to IT service providers has increased substantially during the past years. IT service providers must be able to fulfil their service-quality commitments based upon predefined Service Level Agreements (SLAs) with the service customer. They need to manage, execute and maintain thousands of SLAs for different customers and different types of services, which needs new levels of flexibility and automation not available with the current technology. The complexity of contractual logic in SLAs requires new forms of knowledge representation to automatically draw inferences and execute contractual agreements. A logic-based approach provides several advantages including automated rule chaining allowing for compact knowledge representation as well as flexibility to adapt to rapidly changing business requirements. We suggest adequate logical formalisms for representation and enforcement of SLA rules and describe a proof-of-concept implementation. The article describes selected formalisms of the ContractLog KR and their adequacy for automated SLA management and presents results of experiments to demonstrate flexibility and scalability of the approach.Comment: Paschke, A. and Bichler, M.: Knowledge Representation Concepts for Automated SLA Management, Int. Journal of Decision Support Systems (DSS), submitted 19th March 200

Markov Decision Processes with Applications in Wireless Sensor Networks: A Survey

Wireless sensor networks (WSNs) consist of autonomous and resource-limited devices. The devices cooperate to monitor one or more physical phenomena within an area of interest. WSNs operate as stochastic systems because of randomness in the monitored environments. For long service time and low maintenance cost, WSNs require adaptive and robust methods to address data exchange, topology formulation, resource and power optimization, sensing coverage and object detection, and security challenges. In these problems, sensor nodes are to make optimized decisions from a set of accessible strategies to achieve design goals. This survey reviews numerous applications of the Markov decision process (MDP) framework, a powerful decision-making tool to develop adaptive algorithms and protocols for WSNs. Furthermore, various solution methods are discussed and compared to serve as a guide for using MDPs in WSNs

Adaptive age replacement

Bayesian approach to adaptive age replacement treated by dynamic programmin

A Rehabilitation of Economic Replacement Theory

Our objective in this paper is to shed light on the economic forces and the specific way in which they combine to determine the service life, and hence the replacement demand for durables, in the short run and in the long run. For this purpose the received multiperiod economic replacement model is extended in the light of more recent theoretical developments and solved for the number and duration of replacements. Owing mainly to the intuition that the latter decisions are inexplicably related to the owner s profit horizon, aside from steady state replacement, the model is shown to yield a range of transitional and limiting replacement policies that have been largely ignored in the literature. In addition, the results indicate that : a) the optimal service life is consistently determined by such conventional forces of short-term variation as utilization, maintenance, operating safety, interest rate, uncertainty due to technological breakthroughs, the price of new and used durables, etc., b) switching among replacement policies produces bursts or slumps in replacement investment much like the spikes discovered recently at the plant level, and c) in non- stationary economic environments the error from applying steady state replacement, instead of the more appropriate transitory replacement policies reported in this paper, may be substantial.service life, replacement, and scrapping