Service brokerage with Prolog

Service brokerage is a complex problem. At the design stage the semantic gap between user, device and system requirements must be bridged, and at the operational stage the conflicting objectives of many parties in the value chain must be reconciled. For example why should a user who wants to watch a film need to understand that due to limited battery power the film can only be shown in low resolution? Why should the user have to understand the business model of a content provider? To solve these problems we present (1) the concept of a packager who acts as a service broker, (2) a design derived systematically from a semi-formal specification (the CC-model), and (3) an implementation using our Prolog based LicenseScript language

CSNET: A PROPOSAL FOR NETWORK CLEARANCE AND SETTLEMENT

I present a brief introduction to exchange-based clearance and settlement, and current practical and research problems posed by various inefficiencies that exist in this process. Then, open network protocols are reviewed to set the stage for the design of a hypothetical clearance and settlement network (CSnet). Important and desirable attributes such as security, robustness, and extensibility will be discussed. A practical networked implementation of order flow and execution, the Financial Information Exchange (FIX) protocol will be discussed since it parallels in several key areas the CSnet proposal. Further directions for study in the area will be indicated.Information Systems Working Papers Serie

Intermediador de serviços na Nuvem

Mestrado em Engenharia de Computadores e TelemáticaDe acordo com história dos sistemas informáticos, os engenheiros têm vindo a remodelar infraestruturas para melhorar a eficiência das organizações, visando o acesso partilhado a recursos computacionais. O advento da computação em núvem desencadeou um novo paradigma, proporcionando melhorias no alojamento e entrega de serviços através da Internet. Quando comparado com abordagens tradicionais, este apresenta vantajens por disponibilizar acesso ubíquo, escalável e sob demanda, a determinados conjuntos de recursos computacionais partilhados. Ao longo dos últimos anos, observou-se a entrada de novos operadores que providenciam serviços na núvem, a preços competitivos e diferentes acordos de nível de serviço (“Service Level Agreements”). Com a adoção crescente e sem precedentes da computação em núvem, os fornecedores da área estão se a focar na criação e na disponibilização de novos serviços, com valor acrescentado para os seus clientes. A competitividade do mercado e a existência de inúmeras opções de serviços e de modelos de negócio gerou entropia. Por terem sido criadas diferentes terminologias para conceitos com o mesmo significado e o facto de existir incompatibilidade de Interfaces de Programação Aplicacional (“Application Programming Interface”), deu-se uma restrição de fornecedores de serviços específicos na núvem a utilizadores. A fragmentação na faturação e na cobrança ocorreu quando os serviços na núvem passaram a ser contratualizados com diferentes fornecedores. Posto isto, seria uma mais valia existir uma entidade, que harmonizasse a relação entre os clientes e os múltiplos fornecedores de serviços na núvem, por meio de recomendação e auxílio na intermediação. Esta dissertação propõe e implementa um Intermediador de Serviços na Núvem focado no auxílio e motivação de programadores para recorrerem às suas aplicações na núvem. Descrevendo as aplicações de modo facilitado, um algoritmo inteligente recomendará várias ofertas de serviços na núvem cumprindo com os requisitos aplicacionais. Desta forma, é prestado aos utilizadores formas de submissão, gestão, monitorização e migração das suas aplicações numa núvem de núvens. A interação decorre a partir de uma única interface de programação que orquestrará todo um processo juntamente com outros gestores de serviços na núvem. Os utilizadores podem ainda interagir com o Intermediador de Serviços na Núvem a partir de um portal Web, uma interface de linha de comandos e bibliotecas cliente.Throughout the history of computer systems, experts have been reshaping IT infrastructure for improving the efficiency of organizations by enabling shared access to computational resources. The advent of cloud computing has sparked a new paradigm providing better hosting and service delivery over the Internet. It offers advantages over traditional solutions by providing ubiquitous, scalable and on-demand access to shared pools of computational resources. Over the course of these last years, we have seen new market players offering cloud services at competitive prices and different Service Level Agreements. With the unprecedented increasing adoption of cloud computing, cloud providers are on the look out for the creation and offering of new and valueadded services towards their customers. Market competitiveness, numerous service options and business models led to gradual entropy. Mismatching cloud terminology got introduced and incompatible APIs locked-in users to specific cloud service providers. Billing and charging become fragmented when consuming cloud services from multiple vendors. An entity recommending cloud providers and acting as an intermediary between the cloud consumer and providers would harmonize this interaction. This dissertation proposes and implements a Cloud Service Broker focusing on assisting and encouraging developers for running their applications on the cloud. Developers can easily describe their applications, where an intelligent algorithm will be able to recommend cloud offerings that better suit application requirements. In this way, users are aided in deploying, managing, monitoring and migrating their applications in a cloud of clouds. A single API is required for orchestrating the whole process in tandem with truly decoupled cloud managers. Users can also interact with the Cloud Service Broker through a Web portal, a command-line interface, and client libraries

ISIS and META projects

The ISIS project has developed a new methodology, virtual synchony, for writing robust distributed software. High performance multicast, large scale applications, and wide area networks are the focus of interest. Several interesting applications that exploit the strengths of ISIS, including an NFS-compatible replicated file system, are being developed. The META project is distributed control in a soft real-time environment incorporating feedback. This domain encompasses examples as diverse as monitoring inventory and consumption on a factory floor, and performing load-balancing on a distributed computing system. One of the first uses of META is for distributed application management: the tasks of configuring a distributed program, dynamically adapting to failures, and monitoring its performance. Recent progress and current plans are reported

A Marketplace-based Approach to Cloud Network Slice Composition Across Multiple Domains

Cloud network slicing can be defined as the process that enables isolated end-to-end and on-demand networking abstractions, which: (a) contain both cloud and network resources, and (b) are independently controlled, managed and orchestrated. This paper contributes to the vision of the NECOS project and relevant platform, that aim to address the limitations of current cloud computing infrastructures to accomplish the challenging requirements of the slicing approach. The NECOS platform implements the Slice-as-a-Service model, enabling the dynamic creation of end-to-end (E2E) slices from a set of constituent slice parts contributed from multiple domains. A challenging issue is to define the facility that implements dynamic slice resource discovery, aligned to the requirements of the slice owner or tenant, over different infrastructure providers. Here, we propose a Marketplace-based approach implementing relevant federated interactions for the resource discovery and we detail its architecture, workflows, and information model. We also present its initial implementation details and provide both quantitative and qualitative experimental results validating its main operation

Advanced Knowledge Technologies at the Midterm: Tools and Methods for the Semantic Web

The University of Edinburgh and research sponsors are authorised to reproduce and distribute reprints and on-line copies for their purposes notwithstanding any copyright annotation hereon. The views and conclusions contained herein are the author’s and shouldn’t be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of other parties.In a celebrated essay on the new electronic media, Marshall McLuhan wrote in 1962:Our private senses are not closed systems but are endlessly translated into each other in that experience which we call consciousness. Our extended senses, tools, technologies, through the ages, have been closed systems incapable of interplay or collective awareness. Now, in the electric age, the very instantaneous nature of co-existence among our technological instruments has created a crisis quite new in human history. Our extended faculties and senses now constitute a single field of experience which demands that they become collectively conscious. Our technologies, like our private senses, now demand an interplay and ratio that makes rational co-existence possible. As long as our technologies were as slow as the wheel or the alphabet or money, the fact that they were separate, closed systems was socially and psychically supportable. This is not true now when sight and sound and movement are simultaneous and global in extent. (McLuhan 1962, p.5, emphasis in original)Over forty years later, the seamless interplay that McLuhan demanded between our technologies is still barely visible. McLuhan’s predictions of the spread, and increased importance, of electronic media have of course been borne out, and the worlds of business, science and knowledge storage and transfer have been revolutionised. Yet the integration of electronic systems as open systems remains in its infancy.Advanced Knowledge Technologies (AKT) aims to address this problem, to create a view of knowledge and its management across its lifecycle, to research and create the services and technologies that such unification will require. Half way through its sixyear span, the results are beginning to come through, and this paper will explore some of the services, technologies and methodologies that have been developed. We hope to give a sense in this paper of the potential for the next three years, to discuss the insights and lessons learnt in the first phase of the project, to articulate the challenges and issues that remain.The WWW provided the original context that made the AKT approach to knowledge management (KM) possible. AKT was initially proposed in 1999, it brought together an interdisciplinary consortium with the technological breadth and complementarity to create the conditions for a unified approach to knowledge across its lifecycle. The combination of this expertise, and the time and space afforded the consortium by the IRC structure, suggested the opportunity for a concerted effort to develop an approach to advanced knowledge technologies, based on the WWW as a basic infrastructure.The technological context of AKT altered for the better in the short period between the development of the proposal and the beginning of the project itself with the development of the semantic web (SW), which foresaw much more intelligent manipulation and querying of knowledge. The opportunities that the SW provided for e.g., more intelligent retrieval, put AKT in the centre of information technology innovation and knowledge management services; the AKT skill set would clearly be central for the exploitation of those opportunities.The SW, as an extension of the WWW, provides an interesting set of constraints to the knowledge management services AKT tries to provide. As a medium for the semantically-informed coordination of information, it has suggested a number of ways in which the objectives of AKT can be achieved, most obviously through the provision of knowledge management services delivered over the web as opposed to the creation and provision of technologies to manage knowledge.AKT is working on the assumption that many web services will be developed and provided for users. The KM problem in the near future will be one of deciding which services are needed and of coordinating them. Many of these services will be largely or entirely legacies of the WWW, and so the capabilities of the services will vary. As well as providing useful KM services in their own right, AKT will be aiming to exploit this opportunity, by reasoning over services, brokering between them, and providing essential meta-services for SW knowledge service management.Ontologies will be a crucial tool for the SW. The AKT consortium brings a lot of expertise on ontologies together, and ontologies were always going to be a key part of the strategy. All kinds of knowledge sharing and transfer activities will be mediated by ontologies, and ontology management will be an important enabling task. Different applications will need to cope with inconsistent ontologies, or with the problems that will follow the automatic creation of ontologies (e.g. merging of pre-existing ontologies to create a third). Ontology mapping, and the elimination of conflicts of reference, will be important tasks. All of these issues are discussed along with our proposed technologies.Similarly, specifications of tasks will be used for the deployment of knowledge services over the SW, but in general it cannot be expected that in the medium term there will be standards for task (or service) specifications. The brokering metaservices that are envisaged will have to deal with this heterogeneity.The emerging picture of the SW is one of great opportunity but it will not be a wellordered, certain or consistent environment. It will comprise many repositories of legacy data, outdated and inconsistent stores, and requirements for common understandings across divergent formalisms. There is clearly a role for standards to play to bring much of this context together; AKT is playing a significant role in these efforts. But standards take time to emerge, they take political power to enforce, and they have been known to stifle innovation (in the short term). AKT is keen to understand the balance between principled inference and statistical processing of web content. Logical inference on the Web is tough. Complex queries using traditional AI inference methods bring most distributed computer systems to their knees. Do we set up semantically well-behaved areas of the Web? Is any part of the Web in which semantic hygiene prevails interesting enough to reason in? These and many other questions need to be addressed if we are to provide effective knowledge technologies for our content on the web