15,057 research outputs found
A2THOS: Availability Analysis and Optimisation in SLAs
IT service availability is at the core of customer satisfaction and business success for today’s organisations. Many medium-large size organisations outsource part of their IT services to external providers, with Service Level Agreements describing the agreed availability of outsourced service components. Availability management of partially outsourced IT services is a non trivial task since classic approaches for calculating availability are not applicable, and IT managers can only rely on their expertise to fulfil it. This often leads to the adoption of non optimal solutions. In this paper we present A2THOS, a framework to calculate the availability of partially outsourced IT services in the presence of SLAs and to achieve a cost-optimal choice of availability levels for outsourced IT components while guaranteeing a target availability level for the service
Cognitively-inspired Agent-based Service Composition for Mobile & Pervasive Computing
Automatic service composition in mobile and pervasive computing faces many
challenges due to the complex and highly dynamic nature of the environment.
Common approaches consider service composition as a decision problem whose
solution is usually addressed from optimization perspectives which are not
feasible in practice due to the intractability of the problem, limited
computational resources of smart devices, service host's mobility, and time
constraints to tailor composition plans. Thus, our main contribution is the
development of a cognitively-inspired agent-based service composition model
focused on bounded rationality rather than optimality, which allows the system
to compensate for limited resources by selectively filtering out continuous
streams of data. Our approach exhibits features such as distributedness,
modularity, emergent global functionality, and robustness, which endow it with
capabilities to perform decentralized service composition by orchestrating
manifold service providers and conflicting goals from multiple users. The
evaluation of our approach shows promising results when compared against
state-of-the-art service composition models.Comment: This paper will appear on AIMS'19 (International Conference on
Artificial Intelligence and Mobile Services) on June 2
An Integrated Semantic Web Service Discovery and Composition Framework
In this paper we present a theoretical analysis of graph-based service
composition in terms of its dependency with service discovery. Driven by this
analysis we define a composition framework by means of integration with
fine-grained I/O service discovery that enables the generation of a graph-based
composition which contains the set of services that are semantically relevant
for an input-output request. The proposed framework also includes an optimal
composition search algorithm to extract the best composition from the graph
minimising the length and the number of services, and different graph
optimisations to improve the scalability of the system. A practical
implementation used for the empirical analysis is also provided. This analysis
proves the scalability and flexibility of our proposal and provides insights on
how integrated composition systems can be designed in order to achieve good
performance in real scenarios for the Web.Comment: Accepted to appear in IEEE Transactions on Services Computing 201
Intra-Domain Pathlet Routing
Internal routing inside an ISP network is the foundation for lots of services
that generate revenue from the ISP's customers. A fine-grained control of paths
taken by network traffic once it enters the ISP's network is therefore a
crucial means to achieve a top-quality offer and, equally important, to enforce
SLAs. Many widespread network technologies and approaches (most notably, MPLS)
offer limited (e.g., with RSVP-TE), tricky (e.g., with OSPF metrics), or no
control on internal routing paths. On the other hand, recent advances in the
research community are a good starting point to address this shortcoming, but
miss elements that would enable their applicability in an ISP's network.
We extend pathlet routing by introducing a new control plane for internal
routing that has the following qualities: it is designed to operate in the
internal network of an ISP; it enables fine-grained management of network paths
with suitable configuration primitives; it is scalable because routing changes
are only propagated to the network portion that is affected by the changes; it
supports independent configuration of specific network portions without the
need to know the configuration of the whole network; it is robust thanks to the
adoption of multipath routing; it supports the enforcement of QoS levels; it is
independent of the specific data plane used in the ISP's network; it can be
incrementally deployed and it can nicely coexist with other control planes.
Besides formally introducing the algorithms and messages of our control plane,
we propose an experimental validation in the simulation framework OMNeT++ that
we use to assess the effectiveness and scalability of our approach.Comment: 13 figures, 1 tabl
Second Set of Spaces
This document describes the Gloss infrastructure supporting implementation of
location-aware services. The document is in two parts. The first part describes
software architecture for the smart space. As described in D8, a local
architecture provides a framework for constructing Gloss applications, termed
assemblies, that run on individual physical nodes, whereas a global
architecture defines an overlay network for linking individual assemblies. The
second part outlines the hardware installation for local sensing. This
describes the first phase of the installation in Strathclyde University
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