Consulta: subjectFacets:"Data aggregation"
Registros recuperados: 4
Data/hora: 12/06/2024 01:35:49

Disrupting data sharing for a healthier ocean
Provedor de dados: 5
Autores: Pendleton, Linwood H; Beyer, Hawthorne; Estradivari,; Grose, Susan O; Hoegh-guldberg, Ove; Karcher, Denis B; Kennedy, Emma; Llewellyn, Lyndon; Nys, Cecile; Shapiro, Aurélie; Jain, Rahul; Kuc, Katarzyna; Leatherland, Terry; O’hainnin, Kira; Olmedo, Guillermo; Seow, Lynette; Tarsel, Mick; Blasiak, Robert.
Ocean ecosystems are in decline, yet we also have more ocean data, and more data portals, than ever before. To make effective decisions regarding ocean management, especially in the face of global environmental change, we need to make the best use possible of these data. Yet many data are not shared, are hard to find, and cannot be effectively accessed. We identify three classes of challenges to data sharing and use: uploading, aggregating, and navigating. While tremendous advances have occurred to improve ocean data operability and transparency, the effect has been largely incremental. We propose a suite of both technical and cultural solutions to overcome these challenges including the use of natural language processing, automatic data translation,...
Tipo: Text
Palavras-chave: Combinatorial machine; Collaboration; Data aggregation; Data sharing; Data uploading; Ocean conservation.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00500/61162/64743.pdf

Price volatility and accuracy of price risk measurement depending on methods and data aggregation: The case of wheat prices in the EU countries
Provedor de dados: 31
Autores: Figiel,   Szczepan; Hamulczuk,   Mariusz; Klimkowski,   Cezary.
In this paper we use weekly milling wheat price series for nine selected EU countries to evaluate levels and components of volatility in the period from July 2004 to April 2011 and to examine how sensitive the results can be to spatial aggregation of the price data. The prices were analyzed in levels and logarithmic rate of returns. To asses price risk, apart from basic measures of price variability, the price series were decomposed using multiplicative model in order to determine shares of seasonal and random components in the total variance of the prices. We also applied ARMAX model to separate the stochastic components of the price series to properly evaluate real price risk exposure and tested for ARCH and GARCH effects. We found considerable...
Tipo: Presentation
Palavras-chave: Wheat prices; Volatility; Price risk; Data aggregation; Risk and Uncertainty; C22.
Ano: 2012
URL: http://purl.umn.edu/122549

AGGREGATION ISSUES IN PEST CONTROL ECONOMICS: A BIOECONOMIC APPROACH
Provedor de dados: 31
Autores: Young,   Douglas L.; Smith,   Elwin G.; Kwon,   Tae-Jin.
Previous research has defined “aggregate pesticide expenditures” as the control variable; however, virtually all managerial recommendations and environmental restrictions target specific pesticides, rates, and crops. A bioeconomic approach considering particular pesticides on specific pests and crops is recommended for managerial-policy applications and testing for increasing returns. Exponential weed control and seven popular yield damage functional forms were estimated for a bioeconomic weed control model for winter wheat in Washington. Concavity with respect to herbicide rate was observed for most popular damage functions at normal weed densities and manufacturers’ label rates, but convexity existed outside these ranges and should be checked.
Tipo: Conference Paper or Presentation
Palavras-chave: Bioeconomic; Data aggregation; Herbicide; Increasing returns; Pest control; Pesticide; Weed; Crop Production/Industries.
Ano: 2000
URL: http://purl.umn.edu/36448

Does Duality Theory Hold in Practice? A Monte Carlo Analysis for U.S. Agriculture
Provedor de dados: 31
Autores: Rosas,   Francisco; Lence,   Sergio H.
The Neoclassical theory of production establishes a dual relationship between the profit value function of a competitive firm and its underlying production technology. This relationship, usually referred to as the duality theory, has been widely used in empirical work to estimate production parameters without the requirement of explicitly specifying the technology. We analyze the ability of this approach to recover the underlying production parameters and its effects on estimated elasticities and scale economies measurements, when data available for estimation features typical realistic problems. We design alternative scenarios and compute the data generating process by Monte Carlo simulations, so as to know the true technology parameters as well as to...
Tipo: Conference Paper or Presentation
Palavras-chave: Duality theory; Firm’s heterogeneity; Measurement error; Data aggregation; Omitted variables; Endogeneity; Uncertainty; Monte Carlo simulations.; Crop Production/Industries; Production Economics; Risk and Uncertainty; Q12; D22; D81.
Ano: 2011
URL: http://purl.umn.edu/103911