442 research outputs found
Expressiveness and Robustness of First-Price Position Auctions
Since economic mechanisms are often applied to very different instances of
the same problem, it is desirable to identify mechanisms that work well in a
wide range of circumstances. We pursue this goal for a position auction setting
and specifically seek mechanisms that guarantee good outcomes under both
complete and incomplete information. A variant of the generalized first-price
mechanism with multi-dimensional bids turns out to be the only standard
mechanism able to achieve this goal, even when types are one-dimensional. The
fact that expressiveness beyond the type space is both necessary and sufficient
for this kind of robustness provides an interesting counterpoint to previous
work on position auctions that has highlighted the benefits of simplicity. From
a technical perspective our results are interesting because they establish
equilibrium existence for a multi-dimensional bid space, where standard
techniques break down. The structure of the equilibrium bids moreover provides
an intuitive explanation for why first-price payments may be able to support
equilibria in a wider range of circumstances than second-price payments
10 Years of Object-Oriented Analysis on H1
Over a decade ago, the H1 Collaboration decided to embrace the
object-oriented paradigm and completely redesign its data analysis model and
data storage format. The event data model, based on the RooT framework,
consists of three layers - tracks and calorimeter clusters, identified
particles and finally event summary data - with a singleton class providing
unified access. This original solution was then augmented with a fourth layer
containing user-defined objects.
This contribution will summarise the history of the solutions used, from
modifications to the original design, to the evolution of the high-level
end-user analysis object framework which is used by H1 today. Several important
issues are addressed - the portability of expert knowledge to increase the
efficiency of data analysis, the flexibility of the framework to incorporate
new analyses, the performance and ease of use, and lessons learned for future
projects.Comment: 14th International Workshop on Advanced Computing and Analysis
Techniques in Physics Researc
Beitrag zum Vorkommen und Ausbreitung des Trauer-Rosenkäfers Oxythyrea funesta (Poda, 1761) (Coleoptera, Scarabaeidae) in Deutschland:: ein Citizen-Science-Projekt
Der auffällig gezeichnete Trauerrosenkäfer Oxythyrea funesta konnte sich in den letzten 30 Jahren in Mitteleuropa rasant ausbreiten und eignet sich auch deshalb als Modell für Citizen-Science-Projekte. Bei „kerbtier.de“ wurde 2019 ein Kartierungsprojekt gestartet, um die Art durch Fotos der Nutzer gezielt zu melden und die Ausbreitung in Deutschland besser zu dokumentieren. Es wurden insgesamt 1.345 Anfragen von 309 Nutzern ausgewertet. Unsere Ergebnisse bestätigen, dass Oxythyrea funesta mittlerweile aus allen Regionen Deutschlands nachgewiesen ist und in der südlichen Hälfte Deutschlands eine weit verbreitete und häufige Art ist. In Norddeutschland liegt ihr aktueller Verbreitungsschwerpunkt in und um die Städte Hannover, Bremen und Hamburg. Generell scheint die Art vom Klimawandel zu profitieren, sowie durch das Vorhandensein von ausreichend Blütenpflanzen und Komposthaufen in urbanen Gebieten, wo die Art überwiegend dokumentiert wurde. Die Eignung von Citizen-Science-Projekten in der Biodiversitätsforschung wird diskutiert.The characteristic white-spotted rose beetle Oxythyrea funesta has spread rapidly in Central Europe over the past 30 years and is therefore a suitable model for Citizen Science projects. A project to document the dispersal of O. funesta in Germany was started on “kerbtier.de” in 2019 to record the species through photos uploaded by the users. 1,345 inquiries from 309 users were evaluated. Our results show that O. funesta is currently present in all regions of Germany and became a widespread and common species in the southern half of Germany. In Northern Germany, its current distribution is focused in and around the cities of Hanover, Bremen and Hamburg. In general, the species appears to benefit from climate change, as well as from the presence of sufficient flowering plants and compost heaps in urban areas where the species has been mainly documented. The suitability of Citizen-Science-projects in biodiversity research is discussed
Fast urban inundation simulation with RIM2D for flood risk assessment and forecasting
IntroductionUrban pluvial flooding is a growing concern worldwide as consequence of rising urban population and climate change induced increases in heavy rainfall. Easy-to-implement and fast simulation tools are needed to cope with this challenge.MethodsThis study describes the development of the parsimonious, GPU-accelerated hydraulic model RIM2D for urban pluvial flood simulations. This is achieved by considering the built-up urban area as flow obstacles, and by introducing capacity-based approaches to consider urban drainage by infiltration on pervious surfaces and sewer drainage from roofs and sealed surfaces. The model performance was analyzed by simulating 8 heavy rainfall events in a test area in the city of Dresden, Germany. For these events detailed discharge measurements of sewer discharge are available, providing a unique dataset for evaluating the sewer drainage simulation, which is of high importance for realistic pluvial inundation simulations in urban areas.Results and discussionWe show that the model simulates the temporal dynamics of the sewer discharge and the sewer volume within acceptable ranges. Moreover, the erratic variation of the simulated to measured sewer discharge suggests that the deviations from the measurements are caused by the precipitation input rather than the model simplifications. We conclude that RIM2D is a valid tool for urban inundation simulation. Its short simulation runtimes allow probabilistic flood risk assessments and operational flood forecasts
Polarized parton distributions from charged-current deep-inelastic scattering and future neutrino factories
We discuss the determination of polarized parton distributions from
charged-current deep-inelastic scattering experiments. We summarize the
next-to-leading order treatment of charged-current polarized structure
functions, their relation to polarized parton distributions and scale
dependence, and discuss their description by means of a next-to-leading order
evolution code. We discuss current theoretical expectations and positivity
constraints on the unmeasured C-odd combinations Delta q-Delta qbar of
polarized quark distributions, and their determination in charged-current
deep-inelastic scattering experiments. We give estimates of the expected errors
on charged-current structure functions at a future neutrino factory, and
perform a study of the accuracy in the determination of polarized parton
distributions that would be possible at such a facility. We show that these
measurements have the potential to distinguish between different theoretical
scenarios for the proton spin structure.Comment: 35 pages, 13 figures, plain TeX with harvmac; Final version, to be
published in Nucl. Phys. B. Typo in eq 2.13 corrected and two references
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