54,938 research outputs found

    dReDBox: Materializing a full-stack rack-scale system prototype of a next-generation disaggregated datacenter

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    Current datacenters are based on server machines, whose mainboard and hardware components form the baseline, monolithic building block that the rest of the system software, middleware and application stack are built upon. This leads to the following limitations: (a) resource proportionality of a multi-tray system is bounded by the basic building block (mainboard), (b) resource allocation to processes or virtual machines (VMs) is bounded by the available resources within the boundary of the mainboard, leading to spare resource fragmentation and inefficiencies, and (c) upgrades must be applied to each and every server even when only a specific component needs to be upgraded. The dRedBox project (Disaggregated Recursive Datacentre-in-a-Box) addresses the above limitations, and proposes the next generation, low-power, across form-factor datacenters, departing from the paradigm of the mainboard-as-a-unit and enabling the creation of function-block-as-a-unit. Hardware-level disaggregation and software-defined wiring of resources is supported by a full-fledged Type-1 hypervisor that can execute commodity virtual machines, which communicate over a low-latency and high-throughput software-defined optical network. To evaluate its novel approach, dRedBox will demonstrate application execution in the domains of network functions virtualization, infrastructure analytics, and real-time video surveillance.This work has been supported in part by EU H2020 ICTproject dRedBox, contract #687632.Peer ReviewedPostprint (author's final draft

    Diluting the Scalability Boundaries: Exploring the Use of Disaggregated Architectures for High-Level Network Data Analysis

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    Traditional data centers are designed with a rigid architecture of fit-for-purpose servers that provision resources beyond the average workload in order to deal with occasional peaks of data. Heterogeneous data centers are pushing towards more cost-efficient architectures with better resource provisioning. In this paper we study the feasibility of using disaggregated architectures for intensive data applications, in contrast to the monolithic approach of server-oriented architectures. Particularly, we have tested a proactive network analysis system in which the workload demands are highly variable. In the context of the dReDBox disaggregated architecture, the results show that the overhead caused by using remote memory resources is significant, between 66\% and 80\%, but we have also observed that the memory usage is one order of magnitude higher for the stress case with respect to average workloads. Therefore, dimensioning memory for the worst case in conventional systems will result in a notable waste of resources. Finally, we found that, for the selected use case, parallelism is limited by memory. Therefore, using a disaggregated architecture will allow for increased parallelism, which, at the same time, will mitigate the overhead caused by remote memory.Comment: 8 pages, 6 figures, 2 tables, 32 references. Pre-print. The paper will be presented during the IEEE International Conference on High Performance Computing and Communications in Bangkok, Thailand. 18 - 20 December, 2017. To be published in the conference proceeding

    Appraisal Framework for Integrated Transport

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    This working paper outlines an appraisal framework for the Integrated Transport project. The project examined the demand implications from the introduction of a Taktfahrplan timetable onto the east coast mainline rail route. The Taktfahrplan concept is frequently referred to as an interval timetable and is based on trains leaving stations at the same time past the hour throughout the operational day. A stated preference exercise was conducted to estimated what values people placed on such a timetable and these values were added to the more conventional elements of generalised cost to obtain the changes in demand that would result from the introduction of a Taktfahrplan. The working paper is divided into a number of sections that will highlight, • the key implications to arise from the Integrated Transport project; • the demand model; • the appraisal framework; • the data sources used within the appraisal framework; and • the results of the appraisal framework. Interested readers are also referred to the a conference paper that will be presented at the European Transport Conference in Strasbourg later this year (Wardman et al, 2003)

    An HEI-disaggregated input-output table for Wales

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    This paper describes how the education sector of the Welsh Input-Output tables is disaggregated to identify a separate sector for each of Wales’s twelve Higher Education Institutions (HEIs). The process draws on accounting and survey data to accurately determine the incomes and expenditures of each institution. In particular we emphasise determining the HEIs incomes source of origin to inform their treatment, as endogenous or exogenous, in subsequent analyses. The HEI-disaggregated Input-Output table provides a useful descriptive snapshot of the Welsh economy and the role of HEIs within it for a particular year, 2006. The table can be used to derive multipliers and conduct various impact studies of each institution or the sector as a whole. The table is furthermore useful to calibrate other multi-sectoral, HEI-disaggregated models of regional economies, including Social Accounting Matrix (SAM) and computable general equilibrium (CGE) models

    Appraisal Framework for Integrated Transport

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    This working paper outlines an appraisal framework for the Integrated Transport project. The project examined the demand implications from the introduction of a Taktfahrplan timetable onto the east coast mainline rail route. The Taktfahrplan concept is frequently referred to as an interval timetable and is based on trains leaving stations at the same time past the hour throughout the operational day. A stated preference exercise was conducted to estimated what values people placed on such a timetable and these values were added to the more conventional elements of generalised cost to obtain the changes in demand that would result from the introduction of a Taktfahrplan. The working paper is divided into a number of sections that will highlight, • the key implications to arise from the Integrated Transport project; • the demand model; • the appraisal framework; • the data sources used within the appraisal framework; and • the results of the appraisal framework. Interested readers are also referred to the a conference paper that will be presented at the European Transport Conference in Strasbourg later this year (Wardman et al, 2003)

    Supporting high penetrations of renewable generation via implementation of real-time electricity pricing and demand response

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    The rollout of smart meters raises the prospect that domestic customer electrical demand can be responsive to changes in supply capacity. Such responsive demand will become increasingly relevant in electrical power systems, as the proportion of weather-dependent renewable generation increases, due to the difficulty and expense of storing electrical energy. One method of providing response is to allow direct control of customer devices by network operators, as in the UK 'Economy 7' and 'White Meter' schemes used to control domestic electrical heating. However, such direct control is much less acceptable for loads such as washing machines, lighting and televisions. This study instead examines the use of real-time pricing of electricity in the domestic sector. This allows customers to be flexible but, importantly, to retain overall control. A simulation methodology for highlighting the potential effects of, and possible problems with, a national implementation of real-time pricing in the UK domestic electricity market is presented. This is done by disaggregating domestic load profiles and then simulating price-based elastic and load-shifting responses. Analysis of a future UK scenario with 15 GW wind penetration shows that during low-wind events, UK peak demand could be reduced by 8-11 GW. This could remove the requirement for 8-11 GW of standby generation with a capital cost of ÂŁ2.6 to ÂŁ3.6 billion. Recommended further work is the investigation of improved demand-forecasting and the price-setting strategies. This is a fine balance between giving customers access to plentiful, cheap energy when it is available, but increasing prices just enough to reduce demand to meet the supply capacity when this capacity is limited

    Energy performance assessment of HVAC systems by inspection and monitoring

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    The paper discusses the collection and processing of energy performance data as part of the inspection of HVAC systems, aimed at identifying technically feasible and cost-effective Energy Conservation Opportunities (ECO), as required by EPBD. Case studies developed by the HARMONAC project have shown that low-cost or no-cost ECO's - mostly related to system operation and management - can be identified with an effective system monitoring. Building Management Systems (BMS) may be a powerful tool for this task, provided their HW and SW architecture is designed with adequate attention to energy monitoring. Dedicated instrumentation - such as electricity meters and temperature loggers - may also be employed as an alternative / integration to BMS monitoring. The paper also discusses the application of data analysis tools - such as "carpet plots" and "energy signatures" - to the identification of component malfunctioning, control problems, inadequate maintenance, or system schedule optimization, and to the evaluation of achieved energy saving
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