5 resultados para cloud infrastructure

em Research Open Access Repository of the University of East London.


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Provenance plays a pivotal in tracing the origin of something and determining how and why something had occurred. With the emergence of the cloud and the benefits it encompasses, there has been a rapid proliferation of services being adopted by commercial and government sectors. However, trust and security concerns for such services are on an unprecedented scale. Currently, these services expose very little internal working to their customers; this can cause accountability and compliance issues especially in the event of a fault or error, customers and providers are left to point finger at each other. Provenance-based traceability provides a mean to address part of this problem by being able to capture and query events occurred in the past to understand how and why it took place. However, due to the complexity of the cloud infrastructure, the current provenance models lack the expressibility required to describe the inner-working of a cloud service. For a complete solution, a provenance-aware policy language is also required for operators and users to define policies for compliance purpose. The current policy standards do not cater for such requirement. To address these issues, in this paper we propose a provenance (traceability) model cProv, and a provenance-aware policy language (cProvl) to capture traceability data, and express policies for validating against the model. For implementation, we have extended the XACML3.0 architecture to support provenance, and provided a translator that converts cProvl policy and request into XACML type.

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We present Dithen, a novel computation-as-a-service (CaaS) cloud platform specifically tailored to the parallel ex-ecution of large-scale multimedia tasks. Dithen handles the upload/download of both multimedia data and executable items, the assignment of compute units to multimedia workloads, and the reactive control of the available compute units to minimize the cloud infrastructure cost under deadline-abiding execution. Dithen combines three key properties: (i) the reactive assignment of individual multimedia tasks to available computing units according to availability and predetermined time-to-completion constraints; (ii) optimal resource estimation based on Kalman-filter estimates; (iii) the use of additive increase multiplicative decrease (AIMD) algorithms (famous for being the resource management in the transport control protocol) for the control of the number of units servicing workloads. The deployment of Dithen over Amazon EC2 spot instances is shown to be capable of processing more than 80,000 video transcoding, face detection and image processing tasks (equivalent to the processing of more than 116 GB of compressed data) for less than $1 in billing cost from EC2. Moreover, the proposed AIMD-based control mechanism, in conjunction with the Kalman estimates, is shown to provide for more than 27% reduction in EC2 spot instance cost against methods based on reactive resource estimation. Finally, Dithen is shown to offer a 38% to 500% reduction of the billing cost against the current state-of-the-art in CaaS platforms on Amazon EC2 (Amazon Lambda and Amazon Autoscale). A baseline version of Dithen is currently available at dithen.com.

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If a ‘Renaturing of Cities’ strategy is to maximise the ecosystem service provision of urban green infrastructure (UGI), then detailed consideration of a habitat services, biodiversity-led approach and multifunctionality are necessary rather than relying on the assumed benefits of UGI per se. The paper presents preliminary data from three case studies, two in England and one in Germany, that explore how multifunctionality can be achieved, the stakeholders required, the usefulness of an experimental approach for demonstrating transformation, and how this can be fed back into policy. We argue that incorporating locally contextualised biodiversity-led UGI design into the planning and policy spheres contributes to the functioning and resilience of the city and provides the adaptability to respond to locally contextualised challenges, such as overheating, flooding, air pollution, health and wellbeing as well as biodiversity loss. Framing our research to encompass both the science of biodiversity-led UGI and co-developing methods for incorporating a strategic approach to implementation of biodiversity-led UGI by planners and developers addresses a gap in current knowledge and begins to address barriers to UGI implementation. By combining scientific with policy learning and defined urban environmental targets with community needs, our research to date has begun to demonstrate how nature-based solutions to building resilience and adaptive governance can be strategically incorporated within cities through UGI.

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Aim There is growing interest in the contribution of public-private partnerships (PPPs) bridging the shortage of financial resources and management expertise in developing public healthcare infrastructure. However, few studies have evidenced PPPs’ ability in increasing efficiency in public procurement of primary healthcare infrastructure. The aim of this study was to assess to what extent PPPs would increase efficiency in public procurement of primary healthcare facilities. Subject and Methods A qualitative analysis, adopting a realistic research evaluation method, used data collected from a purposive sample of public (n=23) and private sector staff (n=2) directly involved in the UK National Health Service Local Improvement Finance Trust (LIFT). Results We find a positive association of LIFT helping to bridge public sector capital shortages for developing primary care surgeries. LIFT is negatively associated with inefficient procurement because it borrows finance from private banks, leaving public agencies paying high interest rates. The study shows that some contextual factors and mechanisms in LIFT play a major part in obstructing public staff from increasing procurement efficiency. Conclusion PPP’s ability to increase efficiency may be determined by contextual factors and mechanisms that restrict discretion over critical decisions by frontline public sector staff. Developing their capacity in monitoring PPP activities may make partnerships more efficient.

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This article explores policy approaches to educating populations for potential critical infrastructure collapse in five different countries: the UK, the US, Germany, Japan and New Zealand. ‘Critical infrastructure’ is not always easy to define, and indeed is defined slightly differently across countries – it includes entities vital to life, such as utilities (water, energy), transportation systems and communications, and may also include social and cultural infrastructure. The article is a mapping exercise of different approaches to critical infrastructure protection and preparedness education by the five countries. The exercise facilitates a comparison of the countries and enables us to identify distinctive characteristics of each country’s approach. We argue that contrary to what most scholars of security have argued, these national approaches diverge greatly, suggesting that they are shaped more by internal politics and culture than by global approaches.