Nektarios Georgalas

Context modelling and a context-aware framework for pervasive service creation: A model-driven approach

Pervasive service creation entails a complex process that involves a diversity of development aspects. Context-awareness is an important facet of pervasive service creation, which deals with the acquisition, rendering, representation and utilisation of context information. In this paper we tackle context-awareness at the application level dealing with the representation and utilisation of context by services. We propose a model-driven approach that facilitates the creation of a context modelling framework and simplifies the design and implementation of pervasive services. To conclude, we demonstrate the benefits of our model-driven approach via the creation of a pervasive museum service and its evaluation using selected software metrics.

A model driven integration architecture for ontology-based context modelling and context-aware application development

Context-awareness is a very important feature for pervasive services to enhance their flexibility and adaptability to changing conditions and dynamic environments. Using ontologies to model context information and to reason about context at a semantic level has attracted a lot of interest in the research community. However, most of the proposed solutions are ad hoc or proprietary. Therefore, employing standard approaches to formulate the development process becomes of importance. In this paper we examine how OMGs Model Driven Architecture (MDA) can be applied to tackle the issues of context modelling and Context-Aware Application (CAA) modelling and development. A Context Ontology Model (COM) is presented to model context information at two levels: upper-level and extended specific level. A Model Driven Integration Architecture (MDIA) is then proposed to integrate rigorous model specifications and generate CAA implementations either semi-automatically or automatically.

Network service orchestration standardization

Network services underpin operator revenues, and value-added services provide income beyond core (voice and data) infrastructure capability. Today, operators face multiple challenges: a need to innovate and offer a wider choice of value-added services, whilst increasing network scale, bandwidth and flexibility. They must also reduce operational costs, and deploy services far faster - in minutes rather than days or weeks.In the recent years, the network community, motivated by the aforementioned challenges, has developed production network architectures and seeded technologies, like Software Defined Networking, Application-based Network Operations and Network Function Virtualization. These technologies enhance the highly desired properties for elasticity, agility and cost-effectiveness in the operator environment. A key requirement to fully exploit the benefits of these new architectures and technologies is a fundamental shift in management and control of resources, and the ability to orchestrate the network infrastructure: coordinate the instantiation of high-level network services across different technological domains and automate service deployment and re-optimization.This paper surveys existing standardization efforts for the orchestration - automation, coordination, and management - of complex set of network and function resources (both physical and virtual), and highlights the various enabling technologies, strengths and weaknesses, adoption challenges for operators, and areas where further research is required. A survey of the standardization efforts for network service orchestration.Develeop an orchestration architecture and a taxonomy of technologies.A systematic review of standardization across SDOs.Future direction for automated and converged orchestration standards.This is the first survey to blend service orchestration for SDN and NFV.

Pervasive Service Creation using a Model Driven Petri Net Based Approach

Service creation is a complex process that involves service analysis design, implementation and testing. Traditionally, the service is validated at the late stage of testing. This increases development costs since any necessary amendments would require an iterative improving cycle on service design and implementation; until the desired result is eventually reached. This paper proposes a service creation methodology and tooling with a twofold contribution: (i) based on its design, a service is validated early on and prior to implementation, (ii) the service code is automatically generated out of the validated service designs. To achieve this, our approach integrates model-driven architecture (MDA) with Petri Nets (PN). MDA is used to define the (i) Information, (ii) Service Oriented Petri Net (SOPN) and (iii) User Interface modelling languages, which support the service design and implementation phases. Petri Nets facilitate the service validation phase through the use of the SOPN language. By merging the two techniques we obtain a systematic and cost-effective approach for the creation of pervasive services. Concluding the methodology is applied in practice for the creation of a Flight Itinerary booking service.

A Model Driven Approach to Generate Service Creation Environments

The creation of services is a complex activity that involves several tasks. Furthermore this complexity is augmented by the fact that supporting service creation environments are technology-specific. Consequently a technology-independent approach and framework are required to generate service creation environments and drive service creation. In this paper we present such an approach and a generic framework for supporting service creation. The approach realizes service creation via the phases of: (i) domain specific language definition, (ii) model definition and validation, (iii) model-to-model transformation and (iv) model-to-code generation. Each phase maps to a corresponding phase in service creation starting from service analysis to service implementation. The applicability of the approach and its accompanying framework is demonstrated via an example scenario that illustrates the automatic generation of a service creation environment for an online survey system.

An open source domain-specific tools framework to support model driven development of OSS

Telecommunications companies undergo massive transformations which reflect onto exacting requirements for controlling the costs of new Operation Support Systems (OSS) development and integration. This calls for the adoption of new approaches, which improve agility and reusability. Model Drive Development (MDD), as specified by OMG, can drastically tackle these issues and has, therefore, attracted the interest of the telecommunications industry. Equally important is the Open Source paradigm. For MDD to gain wide industrial adoption, tools should be available to facilitate the OSS development process. In this paper, we specify requirements MDD tools should meet for effective application of the approach. An extensive survey is then carried out to evaluate existing meta-modelling frameworks over the identified tools requirements. Eventually, we present the Integrated Eclipse Model driven Environment (IEME), which comprises a unified environment of bundled Eclipse-based MDD facilities that also supports the automatic generation of domain-specific tools.

Towards a Model-Driven Approach for Ontology-Based Context-Aware Application Development: A Case Study

Context-awareness is an essential characteristic for pervasive applications to enhance their flexibility and adaptability to changing conditions and dynamic environments. Using ontologies to model context information and reason about context at a semantic level has attracted a lot of interest in the research community. However, adopting ontologies in the development process of pervasive services introduces additional burden by the further work required for ontology specification and management. This paper studies the use of OMGs model driven architecture in the development process of pervasive services with intent on reducing this burden. In our previous work, we proposed a context ontology model (COM) and a model driven integration architecture (MDIA) for ontology-based context information modelling and context-aware application (CAA) development. In this paper, we present a model transformation mechanism for the generation of the CAA logic and present a case study on a context-aware pervasive service scenario that explains in deep detail how the proposed approach works in practice

A framework that uses repositories for information systems and knowledge integration

Recent market conditions have forced companies to change their policies regarding systems development. Open architectures and distributed paradigms become first role players in the implementation of flexible, componentised systems that can easily adjust to changing requirements. However, there is a significant obstacle put across by the legacy, which still performs the main volume of business processes and stores the majority of the Enterprise Knowledge. Hence, a problem occurs regarding how we obtain integration of systems and knowledge when the legacy still dominates in the enterprise environment. In this paper we advocate that knowledge repositories may provide a solution by becoming the key components of distributed environments. Repositories support strong mechanisms for meta-level information management and systems specification. We present how a repository manages to integrate enterprise knowledge and IS at a conceptual level. Subsequently, we analyse the way a repository-based framework integrates knowledge and software components at a functional level. The analysis is based on the DELOS environment. An example practically exhibits the results achieved.

The role of SDN and NFV for flexible optical networks: Current status, challenges and opportunities

Todays optical transport domains are typically built using fixed grid technology. They are statically configured and operationally intensive to manage, lacking the capability for dynamic services and elastic bandwidth. Recent research has established the benefits of flexible grid technologies for optical switching allowing dynamic and elastic management of the available bandwidth resources. Combined with Software Defined Networks (SDN) control principles and Network Functions Virtualization (NFV) infrastructure, we have the potential to fundamentally change the way we build, deploy and control network applications built on top of flexible optical networks. This paper outlines the current Internet Engineering Task Force (IETF) developments for standardizing flexible grid optical technologies, and discusses how software-defined and function virtualisation principles have and will continue to provide the key capabilities to further enable flexible optical switching technologies to control and deliver NFV-based services and applications. It addition it describes the benefits for the virtual Content Distribution Network (vCDN) use case when combined with an IETFs SDN framework Application-Based Network Operations (ABNO). Finally, we highlight the research opportunities for furthering the application of SDN and NFV for control and orchestration of flexible optical networks using the IETF ABNO-based framework.

Treasure hunt pervasive games in cultural organisations

This paper introduces an approach of connecting cultural organizations, such as Museums and archaeological sites and enhancing visiting experience in both sites with the use of a treasure hunt game. The paper shows how the treasure hunt game utilizes pervasive technology and connects remotely located groups of users (in a Museum and in an archaeological site) by involving them in a live collaborative activity where one group assists the other to find hidden treasures and discover related information. The paper articulates the educational value of pervasive treasure hunt games. The paper put emphasis on the gamified elements of the system and their role in enhancing the visiting experience and concludes with directions of future work and development.