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| Registros recuperados: 76 | |
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| Islas Monroy, Juan Carlos. |
| Este trabajo muestra empíricamente la existencia del fenómeno de correlación espuria en modelos de regresión de respuesta binaria cuando los datos son generados por diferentes procesos de serie de tiempo. Los modelos estudiados son; el logístico, para observaciones independientes; un modelo de cadena de Markov de primer orden que considera dependencia entre las observaciones; y el de ecuaciones de estimación generalizadas para mediciones repetidas en estudios longitudinales. Los resultados indican que este fenómeno ocurre en los tres modelos de regresión excepto bajo algunas condiciones. Dada la hipótesis nula Ho:β1=0; en el modelo logístico y en el de cadena de Markov, el tamaño de la prueba presenta valores mucho mayores de lo esperado y aumenta... |
| Tipo: Tesis |
Palavras-chave: Modelos de respuesta binaria; Series de tiempo Binary response models; Time series. |
| Ano: 2012 |
URL: http://hdl.handle.net/10521/1017 |
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| García Juárez, José de Jesús. |
| El objetivo de este trabajo es evaluar la eficiencia de las coberturas de precios de maíz blanco operadas por ASERCA. Para el estudio, se utiliza el análisis de cointegración de S. Johansen que consiste en probar la existencia de cointegración entre las variables de series de tiempo, en este caso: precios al mayoreo de maíz blanco, precio a futuro de maíz amarillo cotizado en la Bolsa de Futuros de Chicago (CBOT) y tipo de cambio peso-dólar; esta variable en particular, porque al adquirir una cobertura, existe también un riesgo cambiario dado que tanto la adquisición como la liquidación de las coberturas son realizadas en dólares. Los resultados indican que los precios de maíz al mayoreo de las centrales de abasto de Sinaloa, Jalisco, Estado de México,... |
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Palavras-chave: ASERCA; Cointegración; Riesgo; Serie de tiempo; Cointegration; Risk; Time series; Maestría; Economía. |
| Ano: 2011 |
URL: http://hdl.handle.net/10521/421 |
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| Islas Monroy, Juan Carlos. |
| Este trabajo muestra empíricamente la existencia del fenómeno de correlación espuria en modelos de regresión de respuesta binaria cuando los datos son generados por diferentes procesos de serie de tiempo. Los modelos estudiados son; el logístico, para observaciones independientes; un modelo de cadena de Markov de primer orden que considera dependencia entre las observaciones; y el de ecuaciones de estimación generalizadas para mediciones repetidas en estudios longitudinales. Los resultados indican que este fenómeno ocurre en los tres modelos de regresión excepto bajo algunas condiciones. Dada la hipótesis nula Ho:β1=0; en el modelo logístico y en el de cadena de Markov, el tamaño de la prueba presenta valores mucho mayores de lo esperado y aumenta... |
| Tipo: Tesis |
Palavras-chave: Modelos de respuesta binaria; Series de tiempo; Maestría; Estadística; Binary response models; Time series. |
| Ano: 2007 |
URL: http://hdl.handle.net/10521/1345 |
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| García Juárez, José de Jesús. |
| El objetivo de este trabajo es evaluar la eficiencia de las coberturas de precios de maíz blanco operadas por ASERCA. Para el estudio, se utiliza el análisis de cointegración de S. Johansen que consiste en probar la existencia de cointegración entre las variables de series de tiempo, en este caso: precios al mayoreo de maíz blanco, precio a futuro de maíz amarillo cotizado en la Bolsa de Futuros de Chicago (CBOT) y tipo de cambio peso-dólar; esta variable en particular, porque al adquirir una cobertura, existe también un riesgo cambiario dado que tanto la adquisición como la liquidación de las coberturas son realizadas en dólares. Los resultados indican que los precios de maíz al mayoreo de las centrales de abasto de Sinaloa, Jalisco, Estado de México,... |
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Palavras-chave: ASERCA; Cointegración; Riesgo; Serie de tiempo; Cointegration; Risk; Time series; Maestría; Economía. |
| Ano: 2011 |
URL: http://hdl.handle.net/10521/421 |
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| Koedam, Nico; Vrije Universiteit Brussel; nikoedam@vub.ac.be; Ruiz Luna, Arturo; CIAD-Mazatlan; arluna@victoria.ciad.mx; Troell, Max; Beijer Institute; max@beijer.kva.se; Dahdouh-Guebas, Farid; Vrije Universiteit Brussel; fdahdouh@vub.ac.be. |
| The present study focuses on the Navachiste-San Ignacio-Macapule lagoon complex in northwest Mexico and evaluates the spatiotemporal change in the mangrove area over the last three decades using Landsat MSS and TM imagery. Local ethnobotanical uses of the mangrove forest and local perceptions about the status and recent development of the mangrove forest cover are also analyzed. The results of interviews with 54 inhabitants of four fishing villages in the study area indicated that, overall, Laguncularia racemosa is the most frequently used species in this region of the Mexican Pacific coast, where it serves as firewood and a construction material, particularly for walls and fences. The next-ranked species were Avicennia germinans, which is used for tea,... |
| Tipo: Peer-Reviewed Reports |
Palavras-chave: Mangrove; Ethnobiology; Remote sensing; Time series; Thematic Mapper; Multi-Spectral Scanner; Mexico. |
| Ano: 2005 |
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| Blain,Gabriel C.; Camargo,Marcelo B. P. de. |
| This study aimed to describe the probabilistic structure of the annual series of extreme daily rainfall (Preabs), available from the weather station of Ubatuba, State of São Paulo, Brazil (1935-2009), by using the general distribution of extreme value (GEV). The autocorrelation function, the Mann-Kendall test, and the wavelet analysis were used in order to evaluate the presence of serial correlations, trends, and periodical components. Considering the results obtained using these three statistical methods, it was possible to assume the hypothesis that this temporal series is free from persistence, trends, and periodicals components. Based on quantitative and qualitative adhesion tests, it was found that the GEV may be used in order to quantify the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Extreme values; Adhesion tests; Time series. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162012000300014 |
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| Araújo,Gleyce K. D.; Rocha,Jansle V.; Lamparelli,Rubens A. C.; Rocha,Agmon M.. |
| The search for low subjectivity area estimates has increased the use of remote sensing for agricultural monitoring and crop yield prediction, leading to more flexibility in data acquisition and lower costs comparing to traditional methods such as census and surveys. Low spatial resolution satellite images with higher frequency in image acquisition have shown to be adequate for cropland mapping and monitoring in large areas. The main goal of this study was to map the Summer crops in the State of Paraná, Brazil, using 10-day composition of NDVI SPOT Vegetation data for 2005/2006, 2006/2007 and 2007/2008 cropping seasons. For this, a supervised digital classification method with Parallelepiped algorithm in multitemporal RGB image composites was used, in order... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Remote sensing; Time series; Crop yield estimates. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162011000400014 |
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| Amaro,André L. N.; Yanagi Junior,Tadayuki; Yanagi,Sílvia de N. M.; Ferraz,Gabriel A. E S.; Campos,Alessandro T.. |
| Abstract The aim of the present research was to propose a bioclimatic mapping to classify the thermal comfort and discomfort of rural workers within the state of Minas Gerais, considering historical and future scenarios. Monthly historical series (1976-2014) of minimum, mean and maximum temperature-humidity index (THI), determined through the values of air temperature (minimum, mean and maximum) and relative humidity from 48 weather stations located in the state of Minas Gerais were used to analyze the trends through Mann-Kendall and linear regression assays. The bioclimatic mapping of human comfort, obtained via geostatistical analysis, was developed as a function of the minimum, medium and maximum THI for the historical period (1976-2014) and future... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Human; Biometeorology; Human thermal comfort; THI; Time series. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162018000200173 |
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| Solic, M; Krstulovic, N; Marasovic, I; Baranovic, A; Pucherpetkovic, T; Vucetic, T. |
| Time series (> 20 years) of bacterioplankton, phytoplankton and zooplankton abundances and of phytoplankton production in the Adriatic Sea were analysed. Multivariate methods were used to extract the main patterns of year-to-year changes in abundances (Principal Component Analysis), and to discriminate between years and sites (Multidimensional Scaling). Increasing long-term trends were established for planktonic abundances and phytoplankton production in both coastal and open sea areas, presumably as a result of eutrophication processes. In the open sea, natural factors (water exchange between the Mediterranean and Adriatic Seas, and temperature) were dominant in controlling year-to-year fluctuations of plankton. On the other hand, long-term... |
| Tipo: Text |
Palavras-chave: Plankton; Time series; Natural factors; Man-induced factors. |
| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00093/20386/18053.pdf |
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| Le Fevre-lehoerff, Geneviève; Ibanez, Frédéric; Poniz, Paola; Fromentin, Jean-marc. |
| Planktonic time series collected since 1975 off Gravelines, France, were analysed in the context of climatic changes. Principal component analysis and the cumulative sums method wereapplied to 30 data sets which included meteorological and hydrological parameters and planktonic descriptors. Eight groups of biological descriptors were linked to external parameters. The study of winds highlighted the importance of cyclonic and anticyclonic influences. Seven year cycles appeared clearly in air temperature and in species abundance with different trophic levels for species such as Ternora longicornis, Oikopleura dioica and Sagitta setosa, whereas an 11 yr cycle appeared for Pseudocalanus minutus. A 3 to 4 yr cycle was detected for atmospheric pressure,... |
| Tipo: Text |
Palavras-chave: Time series; Zooplankton; Meteorology; Hydrology; Southern North Sea. |
| Ano: 1995 |
URL: http://archimer.ifremer.fr/doc/00033/14455/11757.pdf |
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| Bru, Noelle; Prouzet, Patrick; Lejeune, Michel. |
| The European eel (Anguilla anguilla) is drastically declining in all its distribution area and listed in the red list of the IUCN (International Union for Conservation of Nature). A rebuilding plan was adopted at European level in 2007, Regulation R(CE) 100/2007, to restore eel abundance to the level observed during the seventies. Its implementation started on the 1(st) of January 2009. This species is heavily threatened by numerous activities including fishing, and its management can only be effective through a systemic approach minimizing the whole range of human-induced impacts on the resource and its habitat. In the framework of the European interregional programme INTERREG IIIB-Atlantic Area-the INDICANG project aimed at elaborating abundance... |
| Tipo: Text |
Palavras-chave: Biomass estimates; Exploitation rate; Time series; River; Glass eel; Anguilla anguilla. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00000/11170/7526.pdf |
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| Soudant, Dominique; Beliaeff, Benoit; Thomas, G. |
| Classical regression analysis can be used to model time series. However, the assumption that model parameters are constant over time is not necessarily adapted to the data. In phytoplankton ecology, the relevance of time-varying parameter values has been shown using a dynamic linear regression model (DLRM). DLRMs, belonging to the class of Bayesian dynamic models, assume the existence of a non-observable time series of model parameters, which are estimated on-line, i.e. after each observation. The aim of this paper was to show how DLRM results could be used to explain variation of a time series of phytoplankton abundance. We applied DLRM to daily concentrations of Dinophysis cf. acuminata, determined in Antifer harbour (French coast of the English... |
| Tipo: Text |
Palavras-chave: Phytoplankton; Dinophysis; Time series; Regression; Dynamic; Bayesian. |
| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00337/44784/44490.pdf |
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| Puillat, Ingrid; Prevosto, Marc; Mercier, Herle; Thomas, S.. |
| In our time emerged the idea of a major environmental degradation, at both local and global scales, in the face of the recurrent human pollution. Consequently in the sake of a sustainable humanity development, of the ethic and of the ecology, the protection and the monitoring of our environment have become a major stake. Many scientific and technical tools contributed to improve the environmental knowledge, as helped remote and in situ observations, and forecast modeling. In situ environmental sensor systems have been designed to be increasingly sustainable even in a hostile environment such as the deep ocean. In a similar way, the infrastructures hosting those sensors are now thought and built to be permanent. In marine sciences these considerations gave... |
| Tipo: Text |
Palavras-chave: Time series; Marine data; Signal processing; Statistics. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00161/27259/25468.pdf |
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| Koranteng, Ka; Mcglade, Jm. |
| Using time series analyses, some physical parameters of the continental shelf waters of the Gulf of Guinea were examined. Analysis of coastal sea surface temperatures from Ghana and Ivory Coast, and offshore sea surface temperatures from the Gulf of Guinea clearly shows spatial and inter-annual patterns of cooling in coastal waters of West Africa. The behaviour of the decomposed trend of coastal and offshore sea surface temperatures, sub-surface: temperature measured at 100 m depth off Ghana and salinity showed that the observational period (1963-1992) could be divided into three climatic periods: the period before 1972, from 1972 to 1982, and the period after 1982. In the first period, sea surface temperature at both coastal and offshore areas and bottom... |
| Tipo: Text |
Palavras-chave: Environnement marin; Afrique de l'Ouest; Séries temporelles; Marine environment; West Africa; Time series. |
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/00322/43363/42852.pdf |
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| Registros recuperados: 76 | |
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