Towards distributed architecture for collaborative cloud services in community networks

Internet and communication technologies have lowered the costs for communities to collaborate, leading to new services like user-generated content and social computing, and through collaboration, collectively built infrastructures like community networks have also emerged. Community networks get formed when individuals and local organisations from a geographic area team up to create and run a community-owned IP network to satisfy the community’s demand for ICT, such as facilitating Internet access and providing services of local interest. The consolidation of today’s cloud technologies offers now the possibility of collectively built community clouds, building upon user-generated content and user-provided networks towards an ecosystem of cloud services. To address the limitation and enhance utility of community networks, we propose a collaborative distributed architecture for building a community cloud system that employs resources contributed by the members of the community network for provisioning infrastructure and software services. Such architecture needs to be tailored to the specific social, economic and technical characteristics of the community networks for community clouds to be successful and sustainable. By real deployments of clouds in community networks and evaluation of application performance, we show that community clouds are feasible. Our result may encourage collaborative innovative cloud-based services made possible with the resources of a community.Peer ReviewedPostprint (author’s final draft

A Service-Oriented Approach for Network-Centric Data Integration and Its Application to Maritime Surveillance

Maritime-surveillance operators still demand for an integrated maritime picture better supporting international coordination for their operations, as looked for in the European area. In this area, many data-integration efforts have been interpreted in the past as the problem of designing, building and maintaining huge centralized repositories. Current research activities are instead leveraging service-oriented principles to achieve more flexible and network-centric solutions to systems and data integration. In this direction, this article reports on the design of a SOA platform, the Service and Application Integration (SAI) system, targeting novel approaches for legacy data and systems integration in the maritime surveillance domain. We have developed a proof-of-concept of the main system capabilities to assess feasibility of our approach and to evaluate how the SAI middleware architecture can fit application requirements for dynamic data search, aggregation and delivery in the distributed maritime domain

The Cord Approach to Extensible Concurrency Control

Database management systems (DBMSs) have been increasingly used for advanced application domains, such as software development environments, workflow management systems, computer-aided design and manufacturing, and managed healthcare. In these domains, the standard correctness model of serializability is often too restrictive. The authors introduce the notion of a concurrency control language (CCL) that allows a database application designer to specify concurrency control policies to tailor the behavior of a transaction manager. A well-crafted set of policies defines an extended transaction model. The necessary semantic information required by the CCL run-time engine is extracted from a task manager, a (logical) module by definition included in all advanced applications. This module stores task models that encode the semantic information about the transactions submitted to the DBMS. They have designed a rule-based CCL, called CORD, and have implemented a run-time engine that can be hooked to a conventional transaction manager to implement the sophisticated concurrency control required by advanced database applications. They present an architecture for systems based on CORD and describe how they integrated the CORD engine with the Exodus Storage Manager to implement altruistic locking

CBProf: Customisable Blockchain-as-a-Service Performance Profiler in Cloud Environments

Blockchain technologies, e.g., Hyperledger Fabric and Sawtooth, have been evolving rapidly during past years and enable potential decentralised innovations in a substantial amount of business applications, e.g. crowd journalism, car-sharing and energy trading. The development of decentralised business applications has to face challenges in selecting suitable blockchain technologies, customising network protocols among distributed peers, and optimising system performance to meet application requirements. Also, manually testing and comparing those different technologies are time-consuming. Therefore, an effective tool is needed for profiling the performance characteristics of blockchain services in different cloud environments. In this paper, we present the Customisable Blockchain-as-a-Service Performance Profiler (CBProf), a tool we developed for automating blockchain deployment and performance profiling in cloud environments. We also provide the implementation and functionality demonstration of this tool

Integrating Transaction Services into Web-based Software Development Environments

Software Development Environments (SDE) require sophisticated database transaction models due to the long-duration,interactive, and cooperative nature of the software engineering activities. Such Extended Transaction Models (ETM) have been proposed and implemented by building application-specific databases for the SDEs. With the development of World Wide Web (WWW), there have been a number of efforts to build SDEs on top of the WWW. Using web servers as the databases to store the software artifacts provided us with a new challenge: how to implement the ETMs in such web-based SDEs without requiring the web servers to be customized specifically according to the application domains of the SDEs. This paper presents our experiences of integrating transaction services into web based SDEs. We evolved from the traditional approach of building a transaction management component that operated on top of a dedicated database to the external transaction server approach. A transaction server, called JPernLite, was built to operate independently of the web servers and provide the necessary extensibility for SDEs to implement their ETMs. The transaction server can be integrated into the SDE via a number of interfaces, and we discuss the pros and cons of each alternative in detail

Transactional Agents for Pervasive Computing

Pervasive computing enables seamless integration of computing technology into everyday life to make upto- date information and services proactively available to the users based on their needs and behaviors. We aim to develop a transaction management scheme as a pertinent component for such environment supported by either structured or ad hoc networks. We propose Transactional Agents for Pervasive COmputing (TAPCO), which utilizes a dynamic hierarchical meta data structure that captures the semantic contents of the underlying heterogeneous data sources. Mobile agents process the transactions collaboratively, to preserve ACID properties without violating local autonomy of the data sources. TAPCO is simulated and compared against Decentralized Serialization Graph Testing (DSGT) protocol. The results show that TAPCO outperforms DSGT in several ways. In contrast to DSGT that did not consider local transactions, TAPCO supports both local and global transactions without violating the local autonomy

An Architecture for Integrating Concurrency Control into Environment Frameworks

Research in layered and componentized systems shows the benefit of dividing the responsibility of services into separate components. It is still an unresolved issue, however, how a system can be created from a set of existing (independently developed) components. This issue of integration is of immense concern to software architects since a proper solution would reduce duplicate implementation efforts and promote component reuse. In this paper we take a step towards this goal within the domain of software development environments (SDEs) by showing how to integrate an external concurrency control component, called Pern, with environment frameworks. We discuss two experiments where we integrated Pern with Oz, a multi-site, decentralized process centered environment, and Process WEAVER, a commercial process server. We introduce an architecture for retrofitting an external concurrency control component into an environment