81,144 research outputs found
Conceptual modelling of adaptive web services based on high-level petri nets
Service technology geared by its SOA architecture and enabling Web services is
rapidly gaining in maturity and acceptance. Consequently, most worldwide
(private and corporate) cross-organizations are embracing this paradigm by
publishing, requesting and composing their businesses and applications in the
form of (web-)services. Nevertheless, to face harsh competitiveness such service oriented
cross-organizational applications are increasingly pressed to be highly
composite, adaptive, knowledge-intensive and very reliable. In contrast to that,
Web service standards such as WSDL, WSBPEL, WS-CDL and many others
offer just static, manual, purely process-centric and ad-hoc techniques to deploy
such services.
The main objective of this thesis consists therefore in leveraging the development
of service-driven applications towards more reliability, dynamically
and adaptable knowledge-intensiveness. This thesis puts forward an innovative
framework based on distributed high-level Petri nets and event-driven business
rules. More precisely, we developed a new variant of high-level Petri Nets formalism
called Service-based Petri nets (CSrv-Nets), that exhibits the following
potential characteristics. Firstly, the framework is supported by a stepwise
methodology that starts with diagrammatical UML-class diagrams and business
rules and leads to dynamically adaptive services specifications. Secondly, the
framework soundly integrates behavioural event-driven business rules and stateful
services both at the type and instance level and with an inherent distribution.
Thirdly, the framework intrinsically permits validation through guided graphical
animation. Fourthly, the framework explicitly separates between orchestrations
for modelling rule-intensive single services and choreography for cooperating
several services through their governing interactive business rules. Fifthly, the
framework is based on a two-level conceptualization: (1) the modelling of any
rule-centric service with CSrv-Nets; (2) the smooth upgrading of this service
modelling with an adaptability-level that allows for dynamically shifting up and
down any rule-centric behavior of the running business activities
Improving perceptual multimedia quality with an adaptable communication protocol
Copyrights @ 2005 University Computing Centre ZagrebInnovations and developments in networking technology have been driven by technical considerations with little analysis of the benefit to the user. In this paper we argue that network parameters that define the network Quality of Service (QoS) must be driven by user-centric parameters such as user expectations and requirements for multimedia transmitted over a network. To this end a mechanism for mapping user-oriented parameters to network QoS parameters is outlined. The paper surveys existing methods for mapping user requirements to the network. An adaptable communication system is implemented to validate the mapping. The architecture adapts to varying network conditions caused by congestion so as to maintain user expectations and requirements. The paper also surveys research in the area of adaptable communications architectures and protocols. Our results show that such a user-biased approach to networking does bring tangible benefits to the user
An ontology framework for developing platform-independent knowledge-based engineering systems in the aerospace industry
This paper presents the development of a novel knowledge-based engineering (KBE) framework for implementing platform-independent knowledge-enabled product design systems within the aerospace industry. The aim of the KBE framework is to strengthen the structure, reuse and portability of knowledge consumed within KBE systems in view of supporting the cost-effective and long-term preservation of knowledge within such systems. The proposed KBE framework uses an ontology-based approach for semantic knowledge management and adopts a model-driven architecture style from the software engineering discipline. Its phases are mainly (1) Capture knowledge required for KBE system; (2) Ontology model construct of KBE system; (3) Platform-independent model (PIM) technology selection and implementation and (4) Integration of PIM KBE knowledge with computer-aided design system. A rigorous methodology is employed which is comprised of five qualitative phases namely, requirement analysis for the KBE framework, identifying software and ontological engineering elements, integration of both elements, proof of concept prototype demonstrator and finally experts validation. A case study investigating four primitive three-dimensional geometry shapes is used to quantify the applicability of the KBE framework in the aerospace industry. Additionally, experts within the aerospace and software engineering sector validated the strengths/benefits and limitations of the KBE framework. The major benefits of the developed approach are in the reduction of man-hours required for developing KBE systems within the aerospace industry and the maintainability and abstraction of the knowledge required for developing KBE systems. This approach strengthens knowledge reuse and eliminates platform-specific approaches to developing KBE systems ensuring the preservation of KBE knowledge for the long term
Domain Objects and Microservices for Systems Development: a roadmap
This paper discusses a roadmap to investigate Domain Objects being an
adequate formalism to capture the peculiarity of microservice architecture, and
to support Software development since the early stages. It provides a survey of
both Microservices and Domain Objects, and it discusses plans and reflections
on how to investigate whether a modeling approach suited to adaptable
service-based components can also be applied with success to the microservice
scenario
Context Aware Adaptable Applications - A global approach
Actual applications (mostly component based) requirements cannot be expressed without a ubiquitous and mobile part for end-users as well as for M2M applications (Machine to Machine). Such an evolution implies context management in order to evaluate the consequences of the mobility and corresponding mechanisms to adapt or to be adapted to the new environment. Applications are then qualified as context aware applications. This first part of this paper presents an overview of context and its management by application adaptation. This part starts by a definition and proposes a model for the context. It also presents various techniques to adapt applications to the context: from self-adaptation to supervised approached. The second part is an overview of architectures for adaptable applications. It focuses on platforms based solutions and shows information flows between application, platform and context. Finally it makes a synthesis proposition with a platform for adaptable context-aware applications called Kalimucho. Then we present implementations tools for software components and a dataflow models in order to implement the Kalimucho platform
Towards Adaptable and Adaptive Policy-Free Middleware
We believe that to fully support adaptive distributed applications,
middleware must itself be adaptable, adaptive and policy-free. In this paper we
present a new language-independent adaptable and adaptive policy framework
suitable for integration in a wide variety of middleware systems. This
framework facilitates the construction of adaptive distributed applications.
The framework addresses adaptability through its ability to represent a wide
range of specific middleware policies. Adaptiveness is supported by a rich
contextual model, through which an application programmer may control precisely
how policies should be selected for any particular interaction with the
middleware. A contextual pattern mechanism facilitates the succinct expression
of both coarse- and fine-grain policy contexts. Policies may be specified and
altered dynamically, and may themselves take account of dynamic conditions. The
framework contains no hard-wired policies; instead, all policies can be
configured.Comment: Submitted to Dependable and Adaptive Distributed Systems Track, ACM
SAC 200
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