Javier Cubo

ITACA: An integrated toolbox for the automatic composition and adaptation of Web services

Adaptation is of utmost importance in systems developed by assembling reusable software services accessed through their public interfaces. This process aims at solving, as automatically as possible, mismatch cases which may be given at the different interoperability levels among interfaces by synthesizing a mediating adaptor. In this paper, we present a toolbox that fully supports the adaptation process, including: (i) different methods to construct adaptation contracts involving several services; (ii) simulation and verification techniques which help to identify and correct erroneous behaviours or deadlocking executions; and (iii) techniques for the generation of centralized or distributed adaptor protocols based on the aforementioned contracts. Our toolbox relates our models with implementation platforms, starting with the automatic extraction of behavioural models from existing interface descriptions, until the final adaptor implementation is generated for the target platform.

A Cloud-Based Internet of Things Platform for Ambient Assisted Living

A common feature of ambient intelligence is that many objects are inter-connected and act in unison, which is also a challenge in the Internet of Things. There has been a shift in research towards integrating both concepts, considering the Internet of Things as representing the future of computing and communications. However, the efficient combination and management of heterogeneous things or devices in the ambient intelligence domain is still a tedious task, and it presents crucial challenges. Therefore, to appropriately manage the inter-connection of diverse devices in these systems requires: (1) specifying and efficiently implementing the devices (e.g., as services); (2) handling and verifying their heterogeneity and composition; and (3) standardizing and managing their data, so as to tackle large numbers of systems together, avoiding standalone applications on local servers. To overcome these challenges, this paper proposes a platform to manage the integration and behavior-aware orchestration of heterogeneous devices as services, stored and accessed via the cloud, with the following contributions: (i) we describe a lightweight model to specify the behavior of devices, to determine the order of the sequence of exchanged messages during the composition of devices; (ii) we define a common architecture using a service-oriented standard environment, to integrate heterogeneous devices by means of their interfaces, via a gateway, and to orchestrate them according to their behavior; (iii) we design a framework based on cloud computing technology, connecting the gateway in charge of acquiring the data from the devices with a cloud platform, to remotely access and monitor the data at run-time and react to emergency situations; and (iv) we implement and generate a novel cloud-based IoT platform of behavior-aware devices as services for ambient intelligence systems, validating the whole approach in real scenarios related to a specific ambient assisted living application.

Formalizing WSBPEL Business Processes Using Process Algebra

Industry standards for Web Service composition, such as WSBPEL, provide the notation and additional control mechanisms for the execution of business processes in Web Service collaborations. However, these standards do not provide support for checking interesting properties related to Web Service and process behaviour. In an attempt to fill this gap, we describe a formalization of WSBPEL business processes, that adds protocol information to the specifications of interacting Web Services, and uses a process algebra to model their dynamic behaviour - thus enabling their formal analysis and the inference of relevant properties of the systems being built.

A Model-Based Approach to the Verification and Adaptation of WF/.NET Components

This paper presents an approach which supports verification and model-based adaptation of software components and services implemented using Windows Workflow Foundation (WF). First, we propose an abstract description of WF workflows, and we formalise the extraction of Labelled Transition Systems from these workflows. Next, verification and adaptation are applied using respectively model-checking techniques and existing model-based adaptation approaches. Last, we explain how a WF workflow can be generated from an adaptor protocol.

SeaClouds: a European project on seamless management of multi-cloud applications

The adaptive management of complex applications deployed across multiple heterogeneous PaaS platforms is one of the problems that have emerged with the cloud revolution. The recently started EU research project SeaClouds aims at providing seamless adaptive multi-cloud management of complex applications by supporting the distribution, monitoring and migration of application modules over multiple heterogeneous PaaS platforms. We present the context, motivations and objectives of SeaClouds, its relation with other cloud initiatives, and its initial architecture.

An Aspect-Oriented Adaptation Framework for Dynamic Component Evolution

This paper briefly describes the design of a dynamic adaptation management framework which exploits the concepts provided by Aspect-Oriented Software Development (AOSD), in particular Aspect-Oriented Programming (AOP). The framework uses reflection and adaptation techniques in order to support COTS composition and evolution by tackling issues related to signature and protocol interoperability. This provides a basic infrastructure for a non-intrusive, semi-automatic approach for syntactical and behavioural adaptation.

Context-based adaptation of component behavioural interfaces

In the development of component-based systems, components need to be adapted in most of the occasions to work under certain conditions which were not initially predicted by their developers. These conditions are likely to change at runtime, therefore it is very important to provide systems with the ability to alter their behaviour while they are running, depending on the changing conditions of the environment. This paper presents an expressive and graphically-based notation to specify flexible adaptation policies (or mappings) between the interfaces of two or more components to be integrated. In a second step, we propose an algorithm which automatically derives the resulting adaptor from a mapping, and a description of component interfaces. We illustrate our proposal using an E-book system.

A Formal Framework for Structural Reconfiguration of Components under Behavioural Adaptation

A major asset of modern systems is to dynamically reconfigure systems to cope with failures or component updates. Nevertheless, designing such systems with off-the-shelf components is hardly feasible: components are black-boxes that can only interact with others on compatible interfaces. Part of the problem is solved through Software Adaptation techniques, which compensates mismatches between interfaces. Our approach aims at using results of Software Adaptation in order to also provide reconfiguration capabilities to black-box components. This paper provides two contributions: (i) a formal framework that unifies behavioural adaptation and structural reconfiguration of components; this is used for statically reasoning whether it is possible to reconfigure a system. And (ii), two cases of reconfiguration in a client/server system in which the server is substituted by another one with a different behavioural interface, and the system keeps on working transparently from the clients point of view.

A Model to Design and Verify Context-Aware Adaptive Service Composition

The introduction of mobile clients and context-aware behaviors into Web Service compositions may generate faults and inconsistencies. We introduce an extension of a composition model where context-awareness is made explicit and a number of correctness properties are verifiable. In particular, our extended model enables the verification of properties commonly used to validate context dependent applications. We also propose a set of algorithms to verify these properties efficiently.

Dynamic Contextual Adaptation

When developing systems based on COTS, components need to be adapted in most of the occasions to work under certain conditions which were not initially predicted by their developers. Thus, it is very important to provide systems with the skill to dynamically alter their behaviour while running, depending on the changing conditions of the environment. In this work we describe a context-dependent, dynamic mapping between the interfaces of the components being adapted, overcoming some of the limitations of the static mappings presented in previous works. This is achieved by means of contextual environments, which define flexible adaptation policies. We also present a case study, illustrating the proposal, and discuss the improvements these mappings represent in comparison with previous works, as well as some open issues.