1,295 research outputs found
Cohomological Arithmetic Statistics for Principally Polarized Abelian Varieties over Finite Fields
There is a natural probability measure on the set of isomorphism classes of
principally polarized Abelian varieties of dimension over ,
weighted by the number of automorphisms. The distributions of the number of
-rational points are related to the cohomology of fiber powers of
the universal family of principally polarized Abelian varieties. To that end we
compute the cohomology for
using results of Eichler-Shimura and for using results of
Lee-Weintraub and Petersen, and we compute the compactly supported Euler
characteristics for
using results of Hain and conjectures of Bergstr\"om-Faber-van der Geer.
In each of these cases we identify the range in which the point counts
are polynomial in . Using results
of Borel and Grushevsky-Hulek-Tommasi on cohomological stability, we adapt
arguments of Achter-Erman-Kedlaya-Wood-Zureick-Brown to pose a conjecture about
the asymptotics of the point counts
in the limit .Comment: 29 pages, comments welcome
Global thermodynamic behaviour of supercritical fluids: example of methane and ethane
Do to the fluctuations associated with the critical region of fluids. The behavior of thermodynamic properties these can not be predicted by mean field theories. To do so, a global equation of state based on the crossover model has been used. This equation of state is formulated on the basis of comparison of selected measurements of pressure-density-temperature data, isochoric and isobaric heat capacity of fluids.The model can be applied in a wide range of temperatures and densities around the critical point for ethane and methane. It is found that the developed model represents most of the reliable experimental data accurately
Do not Waste Money on Advertising Spend: Bid Recommendation via Concavity Changes
In computational advertising, a challenging problem is how to recommend the
bid for advertisers to achieve the best return on investment (ROI) given budget
constraint. This paper presents a bid recommendation scenario that discovers
the concavity changes in click prediction curves. The recommended bid is
derived based on the turning point from significant increase (i.e. concave
downward) to slow increase (convex upward). Parametric learning based method is
applied by solving the corresponding constraint optimization problem. Empirical
studies on real-world advertising scenarios clearly demonstrate the performance
gains for business metrics (including revenue increase, click increase and
advertiser ROI increase).Comment: 10 page
Demystifying Advertising Campaign Bid Recommendation: A Constraint target CPA Goal Optimization
In cost-per-click (CPC) or cost-per-impression (CPM) advertising campaigns,
advertisers always run the risk of spending the budget without getting enough
conversions. Moreover, the bidding on advertising inventory has few connections
with propensity one that can reach to target cost-per-acquisition (tCPA) goals.
To address this problem, this paper presents a bid optimization scenario to
achieve the desired tCPA goals for advertisers. In particular, we build the
optimization engine to make a decision by solving the rigorously formalized
constrained optimization problem, which leverages the bid landscape model
learned from rich historical auction data using non-parametric learning. The
proposed model can naturally recommend the bid that meets the advertisers'
expectations by making inference over advertisers' historical auction
behaviors, which essentially deals with the data challenges commonly faced by
bid landscape modeling: incomplete logs in auctions, and uncertainty due to the
variation and fluctuations in advertising bidding behaviors. The bid
optimization model outperforms the baseline methods on real-world campaigns,
and has been applied into a wide range of scenarios for performance improvement
and revenue liftup
THE FACTORS DETERMINING PROFITABILITY OF GRAIN PRODUCTION IN A REGION
The research was conducted in order to determine influence of structural factors on profitability of grain production in the Altai Region, which is one of the main producers of grain in Russia. The influence of specialization and placement on the economic efficiency of grain production in the Altai Region was determined, factors for the formation of financial results and the financial condition of grain-type organizations were revealed. Comparison of agricultural organizations for which grain farming was the main production sector indicates that in case of increase in the cultivation area, the economic efficiency of resource use will be increased, despite higher costs per hectare of grain crops. The variation of organizations in the profitability of production is explained by the imperfection of the management system of the main branches in separate agricultural organizations, including non-optimal production volumes and placement in natural and economic zones. In the largest highly tailored organizations the economic efficiency of the resources used increased in the short-term perspective rose, but risks of its decline are created in the long-term period
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