203,337 research outputs found

    Model Based Development of Quality-Aware Software Services

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    Modelling languages and development frameworks give support for functional and structural description of software architectures. But quality-aware applications require languages which allow expressing QoS as a first-class concept during architecture design and service composition, and to extend existing tools and infrastructures adding support for modelling, evaluating, managing and monitoring QoS aspects. In addition to its functional behaviour and internal structure, the developer of each service must consider the fulfilment of its quality requirements. If the service is flexible, the output quality depends both on input quality and available resources (e.g., amounts of CPU execution time and memory). From the software engineering point of view, modelling of quality-aware requirements and architectures require modelling support for the description of quality concepts, support for the analysis of quality properties (e.g. model checking and consistencies of quality constraints, assembly of quality), tool support for the transition from quality requirements to quality-aware architectures, and from quality-aware architecture to service run-time infrastructures. Quality management in run-time service infrastructures must give support for handling quality concepts dynamically. QoS-aware modeling frameworks and QoS-aware runtime management infrastructures require a common evolution to get their integration

    A reference architecture for multi-level SLA management

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    There is a global trend towards service-orientation, both for organizing business interactions but also in modern IT architectures. At the business-level, service industries are becoming the dominating sector in which solutions are flexibly composed out of networked services. At the IT level, the paradigms of Service-Oriented Architecture and Cloud Computing realize service-orientation for both software and infrastructure services. Again, flexible composition across different layers is a major advantage of this paradigm. Service Level Agreements (SLA) are a common approach for specifying the exact conditions under which services are to be delivered and, thus, are a prerequisite for supporting the flexible trading of services. However, typical SLAs are just specified at a single layer and do not allow service providers to manage their service stack accordingly. They have no insight on how SLAs at one layer translate to metrics or parameters at the various lower layers of the service stack. In this paper, we present a reference architecture for a multi-level SLA management framework. We discuss the fundamental concepts and detail the main architectural components and interfaces. Furthermore, we show how the framework can be flexibly used for different industrial scenarios

    Transparent Persistence with Java Data Objects

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    Flexible and performant Persistency Service is a necessary component of any HEP Software Framework. The building of a modular, non-intrusive and performant persistency component have been shown to be very difficult task. In the past, it was very often necessary to sacrifice modularity to achieve acceptable performance. This resulted in the strong dependency of the overall Frameworks on their Persistency subsystems. Recent development in software technology has made possible to build a Persistency Service which can be transparently used from other Frameworks. Such Service doesn't force a strong architectural constraints on the overall Framework Architecture, while satisfying high performance requirements. Java Data Object standard (JDO) has been already implemented for almost all major databases. It provides truly transparent persistency for any Java object (both internal and external). Objects in other languages can be handled via transparent proxies. Being only a thin layer on top of a used database, JDO doesn't introduce any significant performance degradation. Also Aspect-Oriented Programming (AOP) makes possible to treat persistency as an orthogonal Aspect of the Application Framework, without polluting it with persistence-specific concepts. All these techniques have been developed primarily (or only) for the Java environment. It is, however, possible to interface them transparently to Frameworks built in other languages, like for example C++. Fully functional prototypes of flexible and non-intrusive persistency modules have been build for several other packages, as for example FreeHEP AIDA and LCG Pool AttributeSet (package Indicium).Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics (CHEP03), La Jolla, Ca, USA, March 2003. PSN TUKT00

    A flexible network architecture for 5G systems

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    In this paper, we define a flexible, adaptable, and programmable architecture for 5G mobile networks, taking into consideration the requirements, KPIs, and the current gaps in the literature, based on three design fundamentals: (i) split of user and control plane, (ii) service-based architecture within the core network (in line with recent industry and standard consensus), and (iii) fully flexible support of E2E slicing via per-domain and cross-domain optimisation, devising inter-slice control and management functions, and refining the behavioural models via experiment-driven optimisation. The proposed architecture model further facilitates the realisation of slices providing specific functionality, such as network resilience, security functions, and network elasticity. The proposed architecture consists of four different layers identified as network layer, controller layer, management and orchestration layer, and service layer. A key contribution of this paper is the definition of the role of each layer, the relationship between layers, and the identification of the required internal modules within each of the layers. In particular, the proposed architecture extends the reference architectures proposed in the Standards Developing Organisations like 3GPP and ETSI, by building on these while addressing several gaps identified within the corresponding baseline models. We additionally present findings, the design guidelines, and evaluation studies on a selected set of key concepts identified to enable flexible cloudification of the protocol stack, adaptive network slicing, and inter-slice control and management.This work has been performed in the framework of the H2020 project 5G-MoNArch co-funded by the E

    Services and Policies for Care at Home

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    It is argued that various factors including the increasingly ageing population will require more care services to be delivered to users in their own homes. Desirable characteristics of such services are outlined. The Open Services Gateway initiative has been adopted as a widely accepted framework that is particularly suitable for developing home care services. Service discovery in this context is enhanced through ontologies that achieve greater flexibility and precision in service description. A service ontology stack allows common concepts to be extended for new services. The architecture of a policy system for home care is explained. This is used for flexible creation and control of new services. The core policy language and its extension for home care are introduced, and illustrated through typical examples. Future extensions of the approach are discussed

    Incorporating an Element of Negotiation into a Service-Oriented Broker Application

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    The Software as a Service (SaaS) model is a service-based model in which a desired service is assembled, delivered and consumed on demand. The IBHIS broker is a ‘proof of concept’ demonstration of SaaS which is based on services that deliver data. IBHIS has addressed a number of challenges for several aspects of servicebased software, especially the concept of a ‘broker service’ and service negotiation that is only used in establishing end-user access authorizations. This thesis investigates and develops an extended form of service-based broker, called CAPTAIN (Care Planning Through Auction-based Information Negotiation). It extends the concepts and role of the broker as used in IBHIS, and in particular, it extends the service negotiation function in order to demonstrate a full range of service characteristics. CAPTAIN uses the idea of the integrated care plan from healthcare to provide a case study. A care planner acting on behalf of a patient uses the broker to negotiate with providers to produce the integrated care plan for the patient with the broker and the providers agreeing on the terms and conditions relating to the supply of the services. We have developed a ‘proof of concept’ service-oriented broker architecture for CAPTAIN that includes planning, negotiation and service-based software models to provide a flexible care planning system. The CAPTAIN application has been evaluated that focuses on three features: functions, data access and negotiation. The CAPTAIN broker performs as planned, to produce the integrated care plan. The providers’ data sources are accessed to read and write data records during and after service negotiation. The negotiation model permits the broker to interact with the providers to produce an adaptable plan, based on the client’s needs. The primary outcome is an extendable service-oriented broker architecture that can enable more scalable and flexible distributed information management by adding interaction with the data sources

    5G Radio Access Network Architecture for Terrestrial Broadcast Services

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    The 3rd Generation Partnership Project (3GPP) has defined based on the Long Term Evolution (LTE) enhanced Multicast Broadcast Multimedia Service (eMBMS) a set of new features to support the distribution of Terrestrial Broadcast services in Release 14. On the other hand, a new 5th Generation (5G) system architecture and radio access technology, 5G New Radio (NR), are being standardised from Release 15 onwards, which so far have only focused on unicast connectivity. This may change in Release 17 given a new Work Item set to specify basic Radio Access Network (RAN) functionalities for the provision of multicast/broadcast communications for NR. This work initially excludes some of the functionalities originally supported for Terrestrial Broadcast services under LTE e.g. free to air, receive-only mode, large-area single frequency networks, etc. This paper proposes an enhanced Next Generation RAN architecture based on 3GPP Release 15 with a series of architectural and functional enhancements, to support an efficient, flexible and dynamic selection between unicast and multicast/broadcast transmission modes and also the delivery of Terrestrial Broadcast services. The paper elaborates on the Cloud-RAN based architecture and proposes new concepts such as the RAN Broadcast/Multicast Areas that allows a more flexible deployment in comparison to eMBMS. High-level assessment methodologies including complexity analysis and inspection are used to evaluate the feasibility of the proposed architecture design and compare it with the 3GPP architectural requirements.Comment: 12 pages, 10 figures, 2 tables, IEEE Trans. Broadcastin

    An open virtual multi-services networking architecture for the future internet

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    © 2015, El Barachi et al.; licensee Springer. Network virtualization is considered as a promising way to overcome the limitations and fight the gradual ossification of the current Internet infrastructure. The network virtualization concept consists in the dynamic creation of several co-existing logical network instances (or virtual networks) over a shared physical network infrastructure. We have previously proposed a service-oriented hierarchical business model for virtual networking environments. This model promotes the idea of network as a service, by considering the functionalities offered by different types of network resources as services of different levels – services that can be dynamically discovered, used, and composed. In this paper, we propose an open, virtual, multi-services networking architecture enabling the realization of our business model. We also demonstrate the operation of our architecture using a virtualized QoS-enabled VoIP scenario. Moreover, virtual routing and control level performance was evaluated using proof-of-concept prototyping. Several important findings were made in the course of this work; one is that service-oriented concepts can be used to build open, flexible, and collaborative virtual networking environments. Another finding is that some of the existing open source virtual routing solutions such as Vyatta are only suitable for building small to medium size virtual networking infrastructures

    An open virtual multi-services networking architecture for the future internet

    Get PDF
    © 2015, El Barachi et al.; licensee Springer. Network virtualization is considered as a promising way to overcome the limitations and fight the gradual ossification of the current Internet infrastructure. The network virtualization concept consists in the dynamic creation of several co-existing logical network instances (or virtual networks) over a shared physical network infrastructure. We have previously proposed a service-oriented hierarchical business model for virtual networking environments. This model promotes the idea of network as a service, by considering the functionalities offered by different types of network resources as services of different levels – services that can be dynamically discovered, used, and composed. In this paper, we propose an open, virtual, multi-services networking architecture enabling the realization of our business model. We also demonstrate the operation of our architecture using a virtualized QoS-enabled VoIP scenario. Moreover, virtual routing and control level performance was evaluated using proof-of-concept prototyping. Several important findings were made in the course of this work; one is that service-oriented concepts can be used to build open, flexible, and collaborative virtual networking environments. Another finding is that some of the existing open source virtual routing solutions such as Vyatta are only suitable for building small to medium size virtual networking infrastructures
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