AO-OpenCom: an AO-Middleware architecture supporting flexible dynamic reconfiguration

Middleware has emerged as a key technology in the construction of distributed systems. As a consequence, middleware is increasingly required to be highly modular and configurable, to support separation of concerns between services, and, crucially, to support dynamic reconfiguration: i.e. to be capable of being changed while running. Aspect-oriented middleware is a promising technology for the realisation of distributed reconfiguration in distributed systems. In this paper we propose an aspect-oriented middleware platform called AO-OpenCom that builds AO-based reconfiguration on top of a dynamic component approach to middleware system composition. The goal is to support extremely flexible dynamic reconfiguration that can be applied at all levels of the system and uniformly across the distributed environment. We evaluate our platform by the capability in meeting flexible reconfiguration and the impact of these overheads

A consistency framework for dynamic reconfiguration in AO-middleware architectures

Aspect-oriented (AO) middleware is a promising technology for the realisation of dynamic reconfiguration in distributed systems. Similar to other dynamic reconfiguration approaches, AO-middleware based reconfiguration requires that the consistency of the system is maintained across reconfigurations. AO middleware based reconfiguration is an ongoing research topic and several consistency approaches have been proposed. However, most of these approaches tend to be targeted at specific narrow contexts, whereas for heterogeneous distributed systems it is crucial to cover a wide range of operating conditions. In this paper we address this problem by exploring a flexible, framework-based consistency management approach that cover a wide range of operating conditions ensuring distributed dynamic reconfiguration in a consistent manner for AO-middleware architectures

An aspect-oriented middleware architecture supporting consistent dynamic reconfiguration

Distributed systems are increasingly being deployed in environments that range from small and tightly-coupled, such as wireless sensor networks, to large and loosely coupled, such as telecommunication systems. Middleware has emerged as a key technology in the construction of such systems, but middleware is increasingly required to be highly modular and configurable, to support separation of concerns between services, and, crucially, to support dynamic reconfiguration: i.e. to be capable of being changed while running. The goal of this thesis is to investigate, design and evaluate a novel approach to middleware-based dynamic reconfiguration that is based on the Aspect Orientation (AO) paradigm. In particular, the thesis proposes an aspect-oriented middleware platform called AO-OpenCom that builds AO-based reconfiguration on top of a dynamic component approach to middleware system composition. The goal is to support extremely flexible dynamic reconfiguration that can be applied both vertically and horizontally: i.e. at all levels of the system and uniformly across the distributed environment. The thesis also proposes a framework-based approach that supports consistent distributed dynamic reconfiguration to avoid problems that arise when reconfiguration operations are, for example, initiated concurrently or in the face of unstable infrastructure or involving contradictory compositions. The approach here is to define a model of potential threats to consistency and to introduce so-called 'threat aspects' that can be dynamically composed with the middleware platform to guard specifically against particular threats. Using dynamically-composed aspects both to realise dynamic reconfiguration and to guard against inconsistency lends simplicity and uniformity to the middleware. Furthermore, the design is recursive in that threat aspects can themselves be protected against other threats using the same approach. For example, a threat aspect addressing a security threat might be protected from security infrastructure crashes by being composed with a threat aspect that offers server replication. Inevitably, the ability to support dynamic reconfiguration and overcome reconfiguration inconsistency comes at the cost of an incurred performance overhead; hence; the thesis also investigates the impact of these overheads.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Experiences of using a hybrid cloud to construct an environmental virtual observatory

Environmental science is often fragmented: data is collected using mismatched formats and conventions, and models are misaligned and run in isolation. Cloud computing offers a lot of potential in the way of resolving such issues by supporting data from different sources and at various scales, by facilitating the integration of models to create more sophisticated software services, and by providing a sustainable source of suitable computational and storage resources. In this paper, we highlight some of our experiences in building the Environmental Virtual Observatory pilot (EVOp), a tailored cloud-based infrastructure and associated web-based tools designed to enable users from different backgrounds to access data concerning different environmental issues. We review our architecture design, the current deployment and prototypes. We also reflect on lessons learned. We believe that such experiences are of benefit to other scientific communities looking to assemble virtual observatories or similar virtual research environments

AO-OpenCom:an AO-middleware architecture supporting flexible dynamic reconfiguration

Middleware has emerged as a key technology in the construction of distributed systems. As a consequence, middleware is increasingly required to be highly modular and configurable, to support separation of concerns between services, and, crucially, to support dynamic reconfiguration: i.e. to be capable of being changed while running. Aspect-oriented middleware is a promising technology for the realisation of distributed reconfiguration in distributed systems. In this paper we propose an aspect-oriented middleware platform called AO-OpenCom that builds AO-based reconfiguration on top of a dynamic component approach to middleware system composition. The goal is to support extremely flexible dynamic reconfiguration that can be applied at all levels of the system and uniformly across the distributed environment. We evaluate our platform by the capability in meeting flexible reconfiguration and the impact of these overheads

Xaas Multi-Cloud marketplace architecture enacting the industry 4.0 concepts

Cloud computing in conjunction with recent advances in Cyber-Physical Systems (CPSs) unravels new opportunities for the European manufacturing industry for high value-added products that can quickly reach the market for sale. The Internet of Things joins the Internet of Services to enact the fourth industrial revolution that digitalises the manufacturing techniques and logistics while pushing forward the development of improved factories with machine-to-machine communication delivering massively customised products tailored to the individualised needs of the customer. Interconnected CPSs using internal and cross-organizational services cooperate in real time increase the business agility and flexibility of manufacturing companies. Using CPS with cloud computing architectures leverage data and services stored and run in cloud environment from different vendors that usually offer different service interfaces to share their services and data. However, when using such architectures data silos appear and different vendors having different service interfaces can easily result in vendor lock-in issues. This paper proposes a multi-cloud marketplace architecture leveraging the existing myriad of different cloud environments at different abstraction levels including the Infrastructure-, Platform-, and Software-as-a-Service cloud models—that is, Everything as a Service or XaaS—delivering services and with different properties that can control the computation happening in multiple cloud environments sharing resources with each other

Augmenting Reflective Middleware with an Aspect Orientation Support Layer

Reflective middleware provides an effective way to support adaptation in distributed systems. However, as distributed systems become increasingly complex, certain drawbacks of the reflective middleware approach are becoming evident. In particular, reflective APIs are found to impose a steep learning curve, and to place too much expressive power in the hands of developers. Recently, researchers in the field of Aspect-Oriented Programming (AOP) have argued that ‘dynamic aspects ’ show promise in alleviating these drawbacks. In this paper, we report on work that attempts to combine the reflective middleware and AOP approaches. We build an AOP support layer on top of an underlying reflective middleware substrate in such a way that it can be dynamically deployed/undeployed where and when required, and imposes no overhead when it is not used. Our AOP approach involves aspects that can be dynamically (un)weaved across a distributed system on the basis of pointcut expressions that are inherently distributed in nature, and it supports the composition of advice that is remote from the advised joinpoint. An overall goal of the work is to effectively combine reflective middleware and AOP in a way that maximises the benefits and minimises the drawbacks of each

A Cloud–Based Approach for Collaborative Networks Supporting Serviced-Enhanced Products

Part 3: GloNet: Service-Enhanced ProductsInternational audienceCollaboration through sharing competencies and resources has been a key approach to both creating new competitive environments, as well as achieving the needed agility to rapidly answer to market demands. Establishing proper collaborative networks for service-enhanced products is challenging considering the wide diversity of business operations and involved resources. The creation of software solutions to support such collaboration is an effort-intensive task, especially when these solutions are designed to run in the cloud and when they are required to be highly customisable to different end-user scenarios. In this paper we describe how a cloud-based platform can support the creation of software solutions for the collaborative development and operation of highly customised and service-enhanced products. The platform has been designed based on numerous key requirements that have been generated from the analysis of different business scenarios from various use cases/domains, as well as general key requirements a cloud based platform should provide to support collaboration among organisations