European marine omics biodiversity observation network: a strategic outline for the implementation of omics approaches in ocean observation

Marine ecosystems, ranging from coastal seas and wetlands to the open ocean, accommodate a wealth of biological diversity from small microorganisms to large mammals. This biodiversity and its associated ecosystem function occurs across complex spatial and temporal scales and is not yet fully understood. Given the wide range of external pressures on the marine environment, this knowledge is crucial for enabling effective conservation measures and defining the limits of sustainable use. The development and application of omics-based approaches to biodiversity research has helped overcome hurdles, such as allowing the previously hidden community of microbial life to be identified, thereby enabling a holistic view of an entire ecosystem’s biodiversity and functioning. The potential of omics-based approaches for marine ecosystems observation is enormous and their added value to ecosystem monitoring, management, and conservation is widely acknowledged. Despite these encouraging prospects, most omics-based studies are short-termed and typically cover only small spatial scales which therefore fail to include the full spatio-temporal complexity and dynamics of the system. To date, few attempts have been made to establish standardised, coordinated, broad scaled, and long-term omics observation networks. Here we outline the creation of an omics-based marine observation network at the European scale, the European Marine Omics Biodiversity Observation Network (EMO BON). We illustrate how linking multiple existing individual observation efforts increases the observational power in large-scale assessments of status and change in biodiversity in the oceans. Such large-scale observation efforts have the added value of cross-border cooperation, are characterised by shared costs through economies of scale, and produce structured, comparable data. The key components required to compile reference environmental datasets and how these should be linked are major challenges that we address.</jats:p

The case for aspect-oriented reflective middleware

The emergence of applications domains such as pervasive and autonomic computing has increased the need for customisation and dynamic adaptation of both distributed systems, and the underlying middleware platforms. Two highly complementary technologies have been advocated to meet these challenges, namely: aspect oriented programming (AOP) and reflective middleware. However, these have so far been considered in isolation, or typically target a particular middleware challenge e.g.using aspects to customise a middleware implementation; or using reflection (or dynamic AOP) to alter runtime behaviour. We believe that in combination these technologies better support the engineering of dynamic distributed systems. In this paper, we explore how aspects and reflection have been utilised in both the programming language and middleware communities; building upon this work, we identify four core relationships that form the basis of our model for aspect-oriented reflective middleware. We then explore the potential of this model to i) increase support for the engineering of dynamic reconfigurations, and ii) improve the performance of adaptive system

True and Transparent Distributed Composition of Aspect-Components

Abstract. Next-generation middleware must support complex compositions that involve dependencies between multiple components residing in different contexts and locations in the network. In this paper we present DyMAC, an aspect-oriented middleware platform that offers an aspect-component model to support such complex distributed compositions by means of advanced remote pointcuts, transparent remote advice and distributed instantiation scopes for aspects. The remote pointcuts can evaluate on calls and executions of remote method invocations and can also evaluate on the distributed context. The remote advice can be executed transparently in a remote environment while still respecting the full semantics of existing types of advice, including around advice. The component model unifies aspects and components into one entity with one interaction standard. To our knowledge, DyMAC middleware is the first AO middleware platform that distributes the concepts of aspect-oriented composition completely and transparently.

A Middleware Layer for Flexible and Cost-Efficient Multi-tenant Applications

Part 7: Security and InteroperabilityInternational audienceApplication-level multi-tenancy is an architectural design principle for Software-as-a-Service applications to enable the hosting of multiple customers (or tenants) by a single application instance. Despite the operational cost and maintenance benefits of application-level multi-tenancy, the current middleware component models for multi-tenant application design are inflexible with respect to providing different software variations to different customers.In this paper we show that this limitation can be solved by a multi-tenancy support layer that combines dependency injection with middleware support for tenant data isolation. Dependency injection enables injecting different software variations on a per tenant basis, while dedicated middleware support facilitates the separation of data and configuration metadata between tenants. We implemented a prototype on top of Google App Engine and we evaluated by means of a case study that the improved flexibility of our approach has little impact on operational costs and upfront application engineering costs

A Model for Developing Component-Based and Aspect-Oriented Systems

Abstract. Aspect-Oriented Programming (AOP) and Component-Based Software Engineering (CBSE) offer solutions to improve the separation of concerns and to enhance a program structure. If the integration of AOP into CBSE has already been proposed, none of these solutions focus on the application of CBSE principles to AOP. In this paper we propose a twofold integration of AOP and CBSE. We introduce a general model for components and aspects, named Fractal Aspect Component (FAC). FAC decomposes a software system into regular components and aspect components (ACs), where an AC is a regular component that embodies a crosscutting concern. We reify the aspect domain of an AC and the relationship between an AC and a component, called an aspect binding, as first-class runtime entities. This clarifies the architecture of a system where components and aspects coexist. The system can evolve from the design to the execution by adding or removing components, aspects or bindings.