Handling Data-Based Concurrency in Context-Aware Service Protocols

Dependency analysis is a technique to identify and determine data dependencies between service protocols. Protocols evolving concurrently in the service composition need to impose an order in their execution if there exist data dependencies. In this work, we describe a model to formalise context-aware service protocols. We also present a composition language to handle dynamically the concurrent execution of protocols. This language addresses data dependency issues among several protocols concurrently executed on the same user device, using mechanisms based on data semantic matching. Our approach aims at assisting the user in establishing priorities between these dependencies, avoiding the occurrence of deadlock situations. Nevertheless, this process is error-prone, since it requires human intervention. Therefore, we also propose verification techniques to automatically detect possible inconsistencies specified by the user while building the data dependency set. Our approach is supported by a prototype tool we have implemented.Comment: In Proceedings FOCLASA 2010, arXiv:1007.499

Towards an aspect weaving BPEL engine

This position paper proposes the use of dynamic aspects and the visitor design pattern to obtain a highly configurable and extensible BPEL engine. Using these two techniques, the core of this infrastructural software can be customised to meet new requirements and add features such as debugging, execution monitoring, or changing to another Web Service selection policy. Additionally, it can easily be extended to cope with customer-specific BPEL extensions. We propose the use of dynamic aspects not only on the engine itself but also on the workflow in order to tackle the problems of Web Service hot deployment and hot fixes to long running processes. In this way, composing aWeb Service "on-the-fly" means weaving its choreography interface into the workflow

Staging Transformations for Multimodal Web Interaction Management

Multimodal interfaces are becoming increasingly ubiquitous with the advent of mobile devices, accessibility considerations, and novel software technologies that combine diverse interaction media. In addition to improving access and delivery capabilities, such interfaces enable flexible and personalized dialogs with websites, much like a conversation between humans. In this paper, we present a software framework for multimodal web interaction management that supports mixed-initiative dialogs between users and websites. A mixed-initiative dialog is one where the user and the website take turns changing the flow of interaction. The framework supports the functional specification and realization of such dialogs using staging transformations -- a theory for representing and reasoning about dialogs based on partial input. It supports multiple interaction interfaces, and offers sessioning, caching, and co-ordination functions through the use of an interaction manager. Two case studies are presented to illustrate the promise of this approach.Comment: Describes framework and software architecture for multimodal web interaction managemen

Model Based Development of Quality-Aware Software Services

Modelling languages and development frameworks give support for functional and structural description of software architectures. But quality-aware applications require languages which allow expressing QoS as a first-class concept during architecture design and service composition, and to extend existing tools and infrastructures adding support for modelling, evaluating, managing and monitoring QoS aspects. In addition to its functional behaviour and internal structure, the developer of each service must consider the fulfilment of its quality requirements. If the service is flexible, the output quality depends both on input quality and available resources (e.g., amounts of CPU execution time and memory). From the software engineering point of view, modelling of quality-aware requirements and architectures require modelling support for the description of quality concepts, support for the analysis of quality properties (e.g. model checking and consistencies of quality constraints, assembly of quality), tool support for the transition from quality requirements to quality-aware architectures, and from quality-aware architecture to service run-time infrastructures. Quality management in run-time service infrastructures must give support for handling quality concepts dynamically. QoS-aware modeling frameworks and QoS-aware runtime management infrastructures require a common evolution to get their integration

Distributed interoperable workflow support for electronic commerce.

Abstract. This paper describes a flexible distributed transactional workflow environment based on an extensible object-oriented framework built around class libraries, application programming interfaces, and shared services. The purpose of this environment is to support a range of EC-like business activities including the support of financial transactions and electronic contracts. This environment has as its aim to provide key infrastructure services for mediating and monitoring electronic commerce.

Towards an Enhanced Protocol for Improving Transactional Support in Interoperable Service Oriented Application-Based (SOA-Based) Systems

When using a shared database for distributed transactions, it is often difficult to connect business processes and softwarecomponents running on disparate platforms into a single transaction. For instance, one platform may add or update data, and thenanother platform later access the changed or added data. This severely limits transactional capabilities across platforms. Thissituation becomes more acute when concurrent transactions with interleaving operations spans across different applications andresources. Addressing this problem in an open, dynamic and distributed environment of web services poses special challenges,and still remains an open issue. Following the broad adoption and use of the standard Web Services Transaction Protocols,requirements have grown for the addition of extended protocols to handle problems that exist within the context of interoperableservice-oriented applications. Most extensions to the current standard WS-Transaction Protocols still lack proper mechanisms forerror-handling, concurrency control, transaction recovery, consolidation of multiple transaction calls into a single call, and securereporting and tracing for suspicious activities. In this research, we will first extend the current standard WS-TransactionFramework, and then propose an enhanced protocol (that can be deployed within the extended framework) to improvetransactional and security support for asynchronous applications in a distributed environment. A hybrid methodology whichincorporates service-oriented engineering and rapid application development will be used to develop a procurement system(which represents an interoperable service-oriented application) that integrates our proposed protocol. We will empiricallyevaluate and compare the performance of the enhanced protocol with other conventional distributed protocols (such as 2PL) interms of QoS parameters (throughput, response time, and resource utilization), availability of the application, databaseconsistency, and effect of locking on latency, among other factors.Keywords: Database, interoperability, security, concurrent transaction, web services, protocol, service-oriente