3,955 research outputs found

    Statistical Power Supply Dynamic Noise Prediction in Hierarchical Power Grid and Package Networks

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    One of the most crucial high performance systems-on-chip design challenge is to front their power supply noise sufferance due to high frequencies, huge number of functional blocks and technology scaling down. Marking a difference from traditional post physical-design static voltage drop analysis, /a priori dynamic voltage drop/evaluation is the focus of this work. It takes into account transient currents and on-chip and package /RLC/ parasitics while exploring the power grid design solution space: Design countermeasures can be thus early defined and long post physical-design verification cycles can be shortened. As shown by an extensive set of results, a carefully extracted and modular grid library assures realistic evaluation of parasitics impact on noise and facilitates the power network construction; furthermore statistical analysis guarantees a correct current envelope evaluation and Spice simulations endorse reliable result

    Improving early design stage timing modeling in multicore based real-time systems

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    This paper presents a modelling approach for the timing behavior of real-time embedded systems (RTES) in early design phases. The model focuses on multicore processors - accepted as the next computing platform for RTES - and in particular it predicts the contention tasks suffer in the access to multicore on-chip shared resources. The model presents the key properties of not requiring the application's source code or binary and having high-accuracy and low overhead. The former is of paramount importance in those common scenarios in which several software suppliers work in parallel implementing different applications for a system integrator, subject to different intellectual property (IP) constraints. Our model helps reducing the risk of exceeding the assigned budgets for each application in late design stages and its associated costs.This work has received funding from the European Space Agency under Project Reference AO=17722=13=NL=LvH, and has also been supported by the Spanish Ministry of Science and Innovation grant TIN2015-65316-P. Jaume Abella has been partially supported by the MINECO under Ramon y Cajal postdoctoral fellowship number RYC-2013-14717.Peer ReviewedPostprint (author's final draft

    The Unbearable Lightness of Regulatory Costs

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    The Article counters the presumption that increased environmental regulation necessarily decreases economic prosperity. It analyzes the European chemical regulatory structure and deduces that any costs imposed on the consumer are minimal, and more cost effective than watered-down American regulations covering the same subject matter with approximately the same cost imposed on the consumer-taxpayer. It argues the Office of Management and Budget and regulated industries have consistently overestimated the costs of environmental regulation and promoted the theory that environmental regulation causes factories and jobs to move offshore. It concludes that deregulation may not spur growth

    Office Market Analysis: Improving Best-Practice Techniques

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    This article focuses on ways to improve market analysis for proposed office projects, taking time and data limitations into account. The discussion moves sequentially through the three primary components of systematic, logical market analysis: the market overview, the market study and the marketability study. Key suggestions cover: (1) discussing megatrends affecting office user preferences and product design; (2) estimating long-term attractiveness of the office location and site; (3) forecasting balance or imbalance between future demand and supply of office space at the metropolitan level; (4) segmenting and differentiating supply and demand at the submarket level for the purpose of assigning market capture rates; and (5) conducting sensitivity analysis of the key variables affecting project net operating income.

    Evaluating the importance of catchment hydrological parameters for urban surface water flood modelling using a simple hydro-inundation model

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    The influence of catchment hydrological processes on urban flooding is often considered through river discharges at a source catchment outlet, negating the role of other upstream areas that may add to the flooding. Therefore, where multiple entry points exist at the urban upstream boundary, e.g. during extreme rainfall events when surface runoff dominates in the catchment, a hydro-inundation model becomes advantageous as it can integrate the hydrological processes with surface flow routing on the urban floodplain. This paper uses a hydro-inundation model (FloodMap-HydroInundation2D) to investigate the role of catchment hydrological parameters in urban surface water flooding. A scenario-based approach was undertaken and the June 2007 event occurred in Kingston upon Hull, UK was used as a baseline simulation, for which a good range of data is available. After model sensitivity analysis and calibration, simulations were designed, considering the improvement of both the urban and rural land drainage and storage capacities. Results suggest the model is sensitive to the key hydrological parameter soil hydraulic conductivity. Sensitivity to mesh resolution and roughness parameterisation also agrees with previous studies on fluvial flood modelling. Furthermore, the improvement of drainage and storage capacity in the upstream rural area is able to alleviate the extent and magnitude of flooding in the downstream urban area. Similarly urban drainage and storage upgrade may also reduce the risks of flooding on site, albeit to a less extent compared to rural improvements. However, none of the improvement scenarios could remove the flow propagation completely. This study highlights that in some settings, urban surface water flood modelling is just as strongly controlled by rural factors (e.g. infiltration rate and water storage) as internal model parameters such as roughness and mesh resolution. It serves as an important reminder to researchers simulating urban flooding that it is not just the internal parameterisation that is important, but also the use of correct inputs from outside the area of study, especially for catchments with a mixture of urban and rural areas

    Limits of agricultural greenhouse gas calculators to predict soil N\u3csub\u3e2\u3c/sub\u3eO and CH\u3csub\u3e4\u3c/sub\u3e fluxes in tropical agriculture

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    Demand for tools to rapidly assess greenhouse gas impacts from policy and technological change in the agricultural sector has catalyzed the development of \u27 GHG calculators\u27-simple accounting approaches that use a mix of emission factors and empirical models to calculate GHG emissions with minimal input data. GHG calculators, however, rely on models calibrated from measurements conducted overwhelmingly under temperate, developed country conditions. Here we show that GHG calculators may poorly estimate emissions in tropical developing countries by comparing calculator predictions against measurements from Africa, Asia, and Latin America. Estimates based on GHG calculators were greater than measurements in 70% of the cases, exceeding twice the measured flux nearly half the time. For 41% of the comparisons, calculators incorrectly predicted whether emissions would increase or decrease with a change in management. These results raise concerns about applying GHG calculators to tropical farming systems and emphasize the need to broaden the scope of the underlying data
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