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—In this paper we consider the general problem of resource provisioning within cloud computing. We analyze the problem of how to allocate resources to different clients such that the service level agreements (SLAs) for all of these clients are met. A model with multiple service request classes generated by different clients is proposed to evaluate the(More)
—Rapid acquisition of accurate crosstalk estimates is a core requirement for effective precoding in digital subscriber line (DSL) systems. It is shown that signal-to-noise ratio (SNR) reports provided by customer premises equipment (CPE) can be used to perform this task by " tuning " the precoder, i.e., iterating alternate steps of estimation and precoder(More)
—Service composition is one of the major approaches in service oriented architecture (SOA) based systems. Due to the inherent stochastic nature of services execution environment the issue of composite service quality assurance within SOA is a very challenging one. Such heterogeneous environment requires dynamic, run–time composition of services. In this(More)
—We investigate dynamic decision mechanisms for composite web services maximizing the expected revenue for the providers of composite services. A composite web service is represented by a (sequential) workflow, and for each of the tasks within this workflow, a number of service alternatives may be available. These alternatives offer the same functionality(More)
Due to the inherent stochastic nature of services execution environment within service oriented systems, a runtime adaptation of the given composition may be required. The authors investigate a runtime service adaptation mechanism based on conditional retries for orchestrated web services. The conditional retry may be issued while a concrete service within(More)
—In this paper we investigate sequential decision mechanisms for composite web services. After executing each sub-service within a sequential workflow, decisions are made whether to terminate or continue the execution of the workflow. These decisions are based on observed response times, expected rewards, and typical Service Level Agreement parameters such(More)
In this paper we consider the runtime service adaptation mechanism for service compositions that is based on conditional retries. A single retry may be issued while a concrete service within composition is executed. This retry could either invoke the same concrete service or a functionally equivalent service implementing the same task. We determine the(More)
In this paper, we analyze overload control for composite web services in service oriented architectures by an orchestrating broker, and propose two practical access control rules which effectively mitigate the effects of severe overloads at some web services in the composite service. These two rules aim to keep overall web service performance (in terms of(More)