6,772 research outputs found

    Implicit Auctioning on the Kontek Cable: Third Time Lucky?

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    Cross-border capacities in Europe are currently inefficiently used. Implicit auctioning is about eliminating these cross-border trade inefficiencies by internalizing the arbitrage into the auction procedures of the Power Exchanges that are organizing trade nationally. On the Kontek Cable, implicit auctioning has been implemented without price coordination between the involved Power Exchanges. This implementation, referred to as “volume or dome coupling” as opposed to “price coupling”, has been argued to be institutionally easier to implement. The Kontek Cable experimented with three different implicit auctioning implementations whose performance we analyze empirically in this paper. We find that the third implementation is significantly outperforming the previous two implementations, but in this third implementation stakeholders partly abandoned the volume coupling approach they initially believed to be a viable alternative to price coupling.electricity, transmission, congestion management, market coupling

    Fast algorithms for matching CCD images to a stellar catalogue

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    Two new algorithms are described for matching two dimensional coordinate lists of point sources that are signifcantly faster than previous methods. By matching rarely occurring triangles (or more complex shapes) in the two lists, and by ordering searches by decreasing probability of success, it is demonstrated that very few candidates need be considered to find a successful match. Moreover, by immediately testing the suitability of a potential match using an efficient mechanism, the need to process the entire candidate set is avoided, yielding considerable performance improvements. Triangles are described by a cosine metric that reduces the density of triangle space, permitting efficient searches. An alternative shape characterization method that reduces computational overhead in the construction phase is discussed. The algorithms are tested on a set of 10 063 wide-field survey images, with fields-of-view up to 4.8 x 3.6 deg, successfully matching 100% of the images in a mean elapsed time of 6 ms (2.4 GHz Athlon CPU). The elapsed time of the searching phase is shown to vary by less than 1 ms for list sizes between 10 and 200 points, demonstrating that fast, robust searches may be completed in nearly constant time, independent of list size.Comment: Accepted for publication in Publications of the Astronomical Society of Australi

    Metal-rich T-dwarfs in the Hyades cluster

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    We present the results of a search for brown dwarfs (BDs) and very low mass (VLM) stars in the 625 Myr-old, metal-rich ([Fe/H]=0.14) Hyades cluster. We performed a deep (I=23, z=22.5) photometric survey over 16 deg2^2 around the cluster center. We report the discovery of the first 2 BDs in the Hyades cluster, with a spectral type T1 and T2, respectively. Their optical and near-IR photometry, as well as their proper motion, are consistent with them being cluster members. According to models, their mass is about 50 Jupiter masses at an age of 625 Myr. We also report the discovery of 3 new very low mass stellar members and confirm the membership of 15 others

    Spatial embeddedness and firm performance: an empirical exploration of the effects of proximity on innovative and economic performance

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    Recent theoretical developments in organisation science and regional economics have emphasised the importance of networks and geographical proximity for the performance of firms. Empirical evidence on these relationships is scarce, though, especially in regional science. In this paper, we address the following research question: to what extent do firm-specific resources, organisational embeddedness, proximity, and industry factors influence innovative and economic outcomes of innovative firms? We used a theoretical synthesis of regional and organisational science to build a research model that enabled us to derive several hypotheses on the influence of proximity on outcomes, taking other important predictors for performance into account. Our empirical findings confirm the importance of proximity especially for innovative outcomes. Moreover, we found that in particular network relations with buyers and suppliers are conducive for firm performance, whereas other indicators of embeddedness and of internal resources have little impact probably due to substitution effects. Finally, regional as well sectoral R&D spillovers influence outcomes in a positive way.

    Why (and how) to regulate Power Exchanges in the EU market integration context?

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    Power Exchanges (PXs) are key market institutions in open and market-based electricity industries. This paper aims at contributing to the ongoing debate on why and how to regulate Power Exchanges in the EU market integration context. . The paper starts by stating that two different types of PXs have to be distinguished, i.e. "Merchant" PXs and the "Cost of Service Regulated" PXs. The paper continues by comparing the typical incentives of these two types of PXs to perform the basic PX tasks in an isolated national market and in a market integration context. The paper concludes by deriving from this analytical frame the most relevant regulatory actions..Regulation, Exchanges, Grid access, Power Markets.

    Pattern of population structuring between Belgian and Estonian bumblebees

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    Several population genetic studies investigated the extent of gene flow and population connectivity in bumblebees. In general, no restriction in gene flow is considered for mainland populations of common bumblebee species. Whether this assumption holds true for all species is not known. An assessment of bumblebee genetic structure in the context of their geographic distribution is needed to prioritize conservation and management needs. Here, we conducted a genetic study on seven bumblebee species occurring in Belgium and Estonia. Using 16 microsatellite markers, we investigated genetic diversity and population structuring in each species. This is the first study investigating population structuring of both declining and stable bumblebee species on both small and large geographic scales. Our results showed no or only low population structuring between the populations of the restricted and declining bumblebee species on both scales, while significant structuring was found for populations of the common species on the larger scale. The latter result, which may be due to human or environmental changes in the landscape, implies the need for the conservation of also widespread bumblebee species. Conservation strategies to improve gene flow and connectivity of populations could avoid the isolation and future losses of populations of these important species

    Mobilizing Cities towards a Low Carbon Future: Tambourines, Carrots and Sticks

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    In the transition towards a decarbonized energy system, we need city authorities to lead by example as public actors, to govern the actions of the private urban actors as local policy makers, and to conceive and manage the implementation of an integrated approach as coordinators, which we introduce in this paper as three levels of city smartness. Local governments however have institutional disincentives to act, and if they do act, they are confronted with urban actors that are reluctant to follow. This paper analyzes how city pioneers in Europe have been able to overcome these disincentives thanks to a combination of local circumstances and interventions by higher levels of government. We categorize the state of the art instruments that have been used by higher levels of government into “tambourines”, “carrots”, and “sticks”, and reflect on how the state of the art could be improved.cities; climate change; governance
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