305 research outputs found

    Managing Alaska’s Coastal Development: State Review of Federal Oil and Gas Lease Sales

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    Contention for shared cache resources has been recognized as a major bottleneck for multicores—especially for mixed workloads of independent applications. While most modern processors implement instructions to manage caches, these instructions are largely unused due to a lack of understanding of how to best leverage them. This paper introduces a classification of applications into four cache usage categories. We discuss how applications from different categories affect each other's performance indirectly through cache sharing and devise a scheme to optimize such sharing. We also propose a low-overhead method to automatically find the best per-instruction cache management policy. We demonstrate how the indirect cache-sharing effects of mixed workloads can be tamed by automatically altering some instructions to better manage cache resources. Practical experiments demonstrate that our software-only method can improve application performance up to 35% on x86 multicore hardware.Coder-mpUPMAR

    Modeling and analysis of power system oscillations using real-time simulator.

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    In this thesis a version of the Kundur two-area model has been developed for Simulink and real time simulator software and hardware from OPAL-RT. This model should be used for testing the rotor angle oscillations load variations create. A review of the different control elements found in basic power systems has been reviewed and implemented. The main component that will be manipulated in the model is the active load, so a zip-load model had to be developed for Simulink to make the system work. It was necessary to build multiple models of the same figure in Simulink, one fixed step version to run in RT-lab, and one variable step to do Simulink tests on. Frequency and voltage stability are not a focus but are mentioned throughout because each of them do affect the system. The lack of secondary frequency reserves leads to never regain nominal rotor speed, and voltage stability affects the simulations done on the RT-lab model. Linear analysis of the stability was done using PST software. The linear results were compared to the variable step model. The results show that the different models behave similarly and manages to simulate what happens with the stability during load changes

    Regulation Awareness and Experience of Additional Monitoring Among Healthcare Professionals in Finland

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    Background: Challenges in post-marketing adverse event reporting are generally recognized. To enhance reporting, the concept of additional monitoring was introduced in 2012. Additional monitoring aims to enhance reporting of adverse events (AE) for medicines for which the clinical evidence base is less well developed. Purpose: The purpose was to get a deeper understanding of the underlying reasons why additional monitoring has not increased AE reporting as much as initially hoped. We examined how healthcare professionals (HCPs) in Finland perceive additional monitoring, why they do or do not report AEs more readily for these medicines and how they interact with patients treated with additionally monitored medicines. Methods: An anonymous, open questionnaire was developed and made available online at the e-form portal of University of Helsinki. Physicians, nurses, and pharmacists were invited to complete the questionnaire via their respective trade or area unions. Content analysis of answers to open-ended questions was performed by two independent coders. Results: Pharmacists have the best understanding about additional monitoring but at the same time do not recognize their role in enhancing monitoring. Only 40% of HCPs working with patients knows always or often if a specific medicine is additionally monitored. Half (53%) of HCPs do not tell or tell only rarely patients about additional monitoring. 18% of HCPs reported having received additional monitoring training whereas 29% had received general AE reporting training. AE reporting was more common among HCPs who had received training. Conclusions: Additional monitoring awareness among HCPs and patients should be increased by organizing regular educational events and making additional monitoring more visible. Educational events should emphasize the significance additional monitoring has on patient safety and promote a reporting culture among HCPs.Peer reviewe

    ALF - A Language for WCET Flow Analysis

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    Static Worst-Case Execution Time (WCET) analysis derives upper bounds for the execution times of programs. Such bounds are crucial when designing and verifying real-time systems. A key component in static WCET analysis is the flow analysis, which derives bounds on the number of times different code entities can be executed. Examples of flow information derived by a flow analysis are loop bounds and infeasible paths. Flow analysis can be performed on source code, intermediate code, or binary code: for the latter, there is a proliferation of instruction sets. Thus, flow analysis must deal with many code formats. However, the basic flow analysis techniques are more or less the same regardless of the code format. Thus, an interesting option is to define a common code format for flow analysis, which also allows for easy translation from the other formats. Flow analyses for this common format will then be portable, in principle supporting all types of code formats which can be translated to this format. Further, a common format simplifies the development of flow analyses, since only one specific code format needs to be targeted. This paper presents such a common code format, the ALF language (ARTIST2 Language for WCET Flow Analysis)

    Warming Up a Cold Front-End with Ignite

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    Serverless computing is a popular software deployment model for the cloud, in which applications are designed as a collection of stateless tasks. Developers are charged for the CPU time and memory footprint during the execution of each  serverless function, which incentivizes them to reduce both runtime and memory usage. As a result, functions tend to be short (often on the order of a few milliseconds) and compact (128–256 MB). Cloud providers can pack thousands of such functions on a server, resulting in frequent context switches and a tremendous degree of interleaving. As a result, when a given memory-resident function is re-invoked, it commonly finds its on-chip microarchitectural state completelycold due to thrashing by other functions — a phenomenon termed lukewarm invocation. Our analysis shows that the cold microarchitectural state due to lukewarm invocations is highly detrimental to performance, which corroborates prior work. The main source of performance degradation is the front-end, composed of instruction delivery, branch identification via the BTB and the conditional branch prediction. State-of-the-art front-end prefetchers show only limited effectiveness on lukewarm invocations, falling considerably short of an ideal front-end. We demonstrate that the reason for this is the cold microarchitectural state of the branch identification and prediction units. In response, we introduce Ignite, a comprehensive restoration mechanism for front-end microarchitectural state targeting instructions, BTB and branch predictor via unified metadata. Ignite records an invocation’s control flow graph in compressed format and uses that to restore the front-end structures the next time the function is invoked. Ignite outperforms state-of-the-art front-end prefetchers, improving performance by an average of 43% by significantly reducing instruction, BTB and branch predictor MPKI

    Factors facilitating intermodal transport of perishable goods – Transport purchasers viewpoint

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    The aim of this article is to identify factors that facilitate increased use of intermodal transport for perishable products based on a survey of firms exporting fresh fish from Norway to Continental Europe. The experiences in the Norwegian aquaculture industry indicate that intermodal transport solutions must be expanded and that the long haul by rail must run all the way to a central hub in Europe. This can only be achieved with a balanced flow of goods and if processors coordinate transport to deliver sufficiently large volumes to fill trains at an acceptable frequency

    Discrimination at the Ports - Welfare Effects of Giving Commuters Priority

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    Author's accepted version (post-print).Available from 01/04/2018.In transport, the problem of demand exceeding capacity often takes place with congestion as a result. The resulting delays imposes substantial efficiency loss. Price discrimination by peak-load pricing is a well-recognized way of handling the problem. Such schemes are, however, often politically controversial because it might disadvantage vulnerable groups of passengers. An alternative is the use of a priority scheme. In this paper, a framework positioned within the traditions of cost-benefit analysis (CBA) is established to analyse the welfare effects of granting one group of passengers’ priority on transport modes characterized by limited capacity and low frequency. The case is a trial arrangement initiated at a rural car ferry crossing in Northern Norway ensuring that local commuters (traveling to and from work) can board at the desired departure. With respect to pricing, it is a stated objective of the road authorities that fares and discounts at ferries are equal throughout the nation. Hence, it is neither desirable nor legal for local political authorities to ensure local commuters a predictable transport alternative by price discrimination. The empirical evidence demonstrates that loss of social welfare caused by congestion problems at the port can be potentially reduced by introducing such a priority scheme. Recommendations are provided with regard to the required number of users required for the priority arrangement to render a positive net benefit for society. This ex ante information is useful for policy makers when evaluating whether to initiate such priority schemes to reduce efficiency loss in passenger transport markets.acceptedVersio

    The academic literature on intermodal freight transport

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    AbstractIt is widely accepted that non-road freight transport is less energy intensive than freight transport by road. The use of other transport modes than truck for long haul freight transport can therefore contribute to more energy efficient transportation systems. As a result, the successful promotion of intermodal transport, using rail or sea on the long haul part, has been identified as the most critical action to achieve a sustainable transport sector. The aim of this paper is twofold. First, we examine the historical development of academic research on intermodal freight transport. Second, we identify the seminal works on the topic. In our analysis we identify and classify the academic literature on intermodal freight transport. This approach has also previously been used to aggregate knowledge about particular fields of research and it aims to be as unbiased as possible by being auditable and repeatable. A timeline on the evolution of the academic literature on intermodal freight transport is presented and the development in publication frequency and topics are commented on in relation to keywords, journals, author affiliations and countries. Publishing frequencies are measured, and reported, both in terms of absolute and relative values. Finally, what is likely the most important and influential papers on intermodal freight transport are identified, using citation frequency

    Exploring the Attractiveness of a Norwegian Rural Higher Education Institution Using Importance-Performance Analysis

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    Author's accepted version (postprint).This is an Accepted Manuscript of an article published by Taylor & Francis in Scandinavian Journal of Educational Research on 15/06/2016, available online: http://www.tandfonline.com/10.1080/00313831.2016.1212254
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