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| Registros recuperados: 16 | |
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| Ning, Wei; Kuan-jiang, Bian; Zhi-fa, Yuan. |
| Based on the 2008 Shaanxi Statistical Yearbook and the relevant data of Shaanxi GDP in the years 1952-2007, SPSS statistical software and time series analysis are used to establish ARIMA (1.2,1) time series model, according to the four steps, recognition rules and stationary test of time series under AIC criterion. ACF graph and PACF graph are used to conduct the applicability test on model. Then, the actual value and predicted value in the years 2002-2007 are compared in order to forecast the GDP of Shaanxi Province in the next 6 years based on this model. Result shows that the relative error of actual value and predicted value is within the range of 5%, and the forecasting effect of this model is relatively good. It is forecasted that the GDP of Shaanxi... |
| Tipo: Journal Article |
Palavras-chave: GDP; ARIMA model; ACF graph; PACF graph; Time series analysis; Agribusiness. |
| Ano: 2010 |
URL: http://purl.umn.edu/93238 |
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| Rouyer, Tristan; Fromentin, Jean-marc; Menard, Felix; Calzelles, B; Briand, K; Pianet, R; Planque, Benjamin; Stenseth, N. |
| The patterns of variations in fisheries time series are known to result from a complex combination of species and fisheries dynamics all coupled with environmental forcing (including climate, trophic interactions, etc.). Disentangling the relative effects of these factors has been a major goal of fisheries science for both conceptual and management reasons. By examining the variability of 169 tuna and billfish time series of catch and catch per unit effort (CPUE) throughout the Atlantic as well as their linkage to the North Atlantic Oscillation (NAO), we find that the importance of these factors differed according to the spatial scale. At the scale of the entire Atlantic the patterns of variations are primarily spatially structured, whereas at a more... |
| Tipo: Text |
Palavras-chave: Time series analysis; North Atlantic Oscillation; Atlantic tuna. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-3984.pdf |
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| Musshoff, Oliver; Hirschauer, Norbert. |
| Agricultural production relies to a great extent on biological processes in natural environments. In addition to volatile prices, it is thus heavily exposed to risks caused by the variability of natural conditions such as rainfall, temperature and pests. With a view to the apparently lacking support of risky farm production program decisions through formal planning models, the objective of this paper is to examine whether, and eventually by how much, farmers’ “intuitive” program decisions can be improved through formal statistical analyses and stochastic optimization models. In this performance comparison, we use the results of the formal planning approach that are generated in a quasi ex-ante analysis as a normative benchmark for the empirically observed... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Stochastic optimization; Program planning; Time series analysis; Crop Production/Industries. |
| Ano: 2008 |
URL: http://purl.umn.edu/44174 |
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| Jordaan, Henry; Grove, Bennie; Jooste, Andre; Alemu, A.G.. |
| The conditional volatility in the daily spot prices of the crops traded on the South African Futures Exchange (yellow maize, white maize, wheat, sunflower seed and soybeans) is determined. The volatility in the prices of white maize, yellow maize and sunflower seed have been found to vary over time, suggesting the use of the GARCH approach in these cases. Using the GARCH approach, the conditional standard deviation is the measure of volatility, and distinguishes between the predictable and unpredictable elements in the price process. This leaves only the stochastic component and is hence a more accurate measure of the actual risk associated with the price of the crop. The volatility in the prices of wheat and soybeans was found to be constant over... |
| Tipo: Journal Article |
Palavras-chave: Price volatility; Field crops; SAFEX; Time series analysis; ARCH/GARCH; Demand and Price Analysis. |
| Ano: 2007 |
URL: http://purl.umn.edu/8013 |
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| Tary, Jean-baptiste; Geli, Louis; Guennou, Claude; Henry, Pierre; Sultan, Nabil; Cagatay, N.; Vidal, V.. |
| Different types of 4-component ocean bottom seismometers (OBS) were deployed for variable durations ranging from 1 week to about 4 months in 2007, over soft sediments covering the seafloor of the Tekirdag Basin (western part of the Sea of Marmara, Turkey). Non-seismic microevents were recorded by the geophones, but generally not by the hydrophones, except when the hydrophone is located less than a few tens of centimetres above the seafloor. The microevents are characterized by short durations of less than 0.8 s, by frequencies ranging between 4 and 30 Hz, and by highly variable amplitudes. In addition, no correlation between OBSs was observed, except for two OBSs, located 10 m apart. Interestingly, a swarm of similar to 400 very similar microevents (based... |
| Tipo: Text |
Palavras-chave: Time series analysis; Gas and hydrate systems; Body waves; Interface waves; Seismic attenuation; Wave propagation. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00089/20012/17825.pdf |
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| Musshoff, Oliver; Hirschauer, Norbert. |
| Agricultural production relies to a great extent on biological processes in natural environments. In addition to volatile prices, it is thus heavily exposed to risks caused by the variability of natural conditions such as rainfall, temperature and pests. With a view to the apparently lacking support of risky farm production program decisions through formal planning models, the objective of this paper is to examine whether, and eventually by how much, farmers’ “intuitive” program decisions can be improved through formal statistical analyses and stochastic optimization models. In this performance comparison, we use the results of the formal planning approach that are generated in a quasi ex-ante analysis as a normative benchmark for the empirically observed... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Stochastic optimization; Stochastic processes; Production risk; Program planning; Time series analysis; C1; C61; M11; Q12. |
| Ano: 2008 |
URL: http://purl.umn.edu/36865 |
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| Corbineau, A; Rouyer, Tristan; Cazelles, B; Fromentin, Jean-marc; Fonteneau, A; Menard, Felix. |
| We analysed the patterns of variation that characterize 33 catch time series of large pelagic fishes exploited by the Japanese and Taiwanese longline fisheries in the Indian Ocean from 1968 to 2003. We selected four species, the yellowfin (Thunnus albacares), the bigeye (T. obesus), the albacore (T. alalunga), and the swordfish (Xiphias gladius) and aggregated data into five biogeographic provinces of Longhurst (2001). We carried out wavelet analyses, an efficient method to study non-stationary time series, in order to get the time-scale patterns of each signals. We then compared and grouped the different wavelet spectra using a multivariate analysis to identify the factors (species, province or fleet) that may influence their clustering. We also... |
| Tipo: Text |
Palavras-chave: Indian Ocean; Dipole Mode Index; Longline fisheries; Wavelet analysis; Time series analysis; Pelagic fishes. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4714.pdf |
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| Registros recuperados: 16 | |
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