scholarly journals Model Hybrid for Sales Forecast for the Housing Market of São Paulo

2020 ◽  
Vol 28 (3) ◽  
pp. 45-64
Author(s):  
Matheus Fernando Moro ◽  
Andreas Dittmar Weise ◽  
Antonio Cezar Bornia
Keyword(s):  
Time Series ◽  
Linear Regression ◽  
Geometric Mean ◽  
Principal Component ◽  
Sao Paulo ◽  
Forecast Combination ◽  
São Paulo ◽  
Forecast Performance ◽  
Sales Forecast ◽  
Residential Units

AbstractThis research proposes a combined model of time series for forecasting housing sales in the city of São Paulo. We used data referring to the time series of sales of residential units provided by SECOVI-SP. The Exponential Softening, Box-Jenkins and Artificial Neural Networks models are individually modelled, later these are combined through five forecast combination techniques.The techniques used are Arithmetic Mean, Geometric Mean, Harmonic Mean, Linear Regression and Principal Component Analysis. The measures of accuracy to measure the results obtained and to select the best model are the RMSE, MAPE and UTheil of forecast. The results showed that Linear Regression with an independent variable, being a combination of the SARIMA model (2,0,0)(2,0,0)12 and MLP/RNA (12,10,1), provided a satisfactory performance, with an RMSE of 368.74, MAPE of 19.2% and UTheil of 0.315.The combination of time series models allowed a significant increase in forecast performance. Finally, the model was validated, using it to predict housing sales. The results show that the model has a good fit, thus demonstrating that using a housing sales forecasting model helps industry professionals minimize error and make sales and launch decisions.

scholarly journals Fee - fishing operation evaluation at Nothwest São Paulo State, Brazil

2005 ◽  
Vol 62 (6) ◽  
pp. 590-596
Author(s):  
Ruy Bessa Lopes ◽  
Luiz de Carvalho Landell Filho ◽  
Carlos Tadeu dos Santos Dias
Keyword(s):  
Fishery Management ◽  
Stocking Density ◽  
Principal Component ◽  
Sao Paulo ◽  
São Paulo ◽  
Productive Performance ◽  
Paulo State ◽  
Productive System ◽  
São Paulo State ◽  
And Cluster Analysis

Fee-fishing operations developed recently in Brazilian agricultural scenery in a rather disordered manner. This study, carried out at the northwest region of São Paulo State, Brazil, focuses on the productive performance of fee-fishing system. Several visits were made monthly to nine fee-fishing establishments, for six months. A questionnaire by owners targeting 13 indicators of the operation's productive performance. Data were submitted to multivariate analysis (MANOVA), principal component analysis (PCA) and cluster analysis. MANOVA indicated significant differences between the fee-fishing operations. The PCA analyses indicated, from the higher coefficient eigenvectors, three attributes for the lakes, such as productive system, fishery management and operational administration. The cluster analyses classified the fishing lakes in four groups. The indicators angler frequency (AF), stocking density (SD), stocking biomass (SB), total capture (TC) and capture/lake/day (CLD), which are part of the attribute productive system, were the most important indicators of "fee-fishing" operations performance in this study.

scholarly journals Magnetic susceptibility to identify landscape segments on a detailed scale in the region of Jaboticabal, São Paulo, Brazil

2012 ◽  
Vol 36 (4) ◽  
pp. 1073-1082 ◽  
Author(s):  
Mariana dos Reis Barrios ◽  
José Marques Junior ◽  
Alan Rodrigo Panosso ◽  
Diego Silva Siqueira ◽  
Newton La Scala Junior
Keyword(s):  
Principal Component Analysis ◽  
Cluster Analysis ◽  
Magnetic Susceptibility ◽  
Clay Fraction ◽  
Chemical Properties ◽  
Principal Component ◽  
Component Analysis ◽  
Sao Paulo ◽  
São Paulo ◽  
Agricultural Potential

The agricultural potential is generally assessed and managed based on a one-dimensional vision of the soil profile, however, the increased appreciation of sustainable production has stimulated studies on faster and more accurate evaluation techniques and methods of the agricultural potential on detailed scales. The objective of this study was to investigate the possibility of using soil magnetic susceptibility for the identification of landscape segments on a detailed scale in the region of Jaboticabal, São Paulo State. The studied area has two slope curvatures: linear and concave, subdivided into three landscape segments: upper slope (US, concave), middle slope (MS, linear) and lower slope (LS, linear). In each of these segments, 20 points were randomly sampled from a database with 207 samples forming a regular grid installed in each landscape segment. The soil physical and chemical properties, CO2 emissions (FCO2) and magnetic susceptibility (MS) of the samples were evaluated represented by: magnetic susceptibility of air-dried fine earth (MS ADFE), magnetic susceptibility of the total sand fraction (MS TS) and magnetic susceptibility of the clay fraction (MS Cl) in the 0.00 - 0.15 m layer. The principal component analysis showed that MS is an important property that can be used to identify landscape segments, because the correlation of this property within the first principal component was high. The hierarchical cluster analysis method identified two groups based on the variables selected by principal component analysis; of the six selected variables, three were related to magnetic susceptibility. The landscape segments were differentiated similarly by the principal component analysis and by the cluster analysis using only the properties with higher discriminatory power. The cluster analysis of MS ADFE, MS TS and MS Cl allowed the formation of three groups that agree with the segment division established in the field. The grouping by cluster analysis indicated MS as a tool that could facilitate the identification of landscape segments and enable the mapping of more homogeneous areas at similar locations.

scholarly journals Seasonality of suicide in the city of Sao Paulo, Brazil, 1979-2003

2009 ◽  
Vol 31 (2) ◽  
pp. 101-105 ◽  
Author(s):  
Daniel Hideki Bando ◽  
Hommenig Scrivani ◽  
Pedro Alberto Morettin ◽  
Chei Tung Teng
Keyword(s):  
Time Series ◽  
Urban Area ◽  
Total Sample ◽  
Sao Paulo ◽  
P Value ◽  
São Paulo ◽  
Zone Method ◽  
Tropical Zone ◽  
Significance Level ◽  
The City

OBJECTIVE: To evaluate suicide seasonality in the city of São Paulo within an urban area and tropical zone. METHOD: Suicides were evaluated using the chi-square test and analysis of variance (ANOVA) by comparing monthly, quarterly and half-yearly variations, differentiating by gender. Analyses of time series were carried out using the autocorrelation function and periodogram, while the significance level for seasonality was confirmed with the Fisher's test. RESULTS: The suicides of the period between 1979 and 2003 numbered 11,434 cases. Differences were observed in suicides occurring in Spring and Autumn for the total sample (ANOVA: p-value = 0.01), and in the male sample (ANOVA: p-value = 0.02). For the analysis of time series, seasonality was significant only for the period of 7 months in the male sample (p-value = 0.04). DISCUSSION: In this study, no significant seasonal differences were observed in the occurrences of suicides, with the exception of the male sample. The differences observed did not correspond with the pattern described in studies carried out in temperate zones. Some of the climatic particularities of the tropical zone might explain the atypical pattern of seasonality of suicides found in large populations within an urban area and tropical zone.

scholarly journals Air pollution and child mortality: a time-series study in São Paulo, Brazil.

2001 ◽  
Vol 109 (suppl 3) ◽  
pp. 347-350 ◽  
Author(s):  
G M Conceição ◽  
S G Miraglia ◽  
H S Kishi ◽  
P H Saldiva ◽  
J M Singer
Keyword(s):  
Air Pollution ◽  
Time Series ◽  
Child Mortality ◽  
Sao Paulo ◽  
São Paulo ◽  
Time Series Study ◽  
Series Study

scholarly journals Low-frequency physical variations in the coastal zone of Ubatuba, northern coast of São Paulo State, Brazil

2013 ◽  
Vol 61 (3) ◽  
pp. 187-193 ◽  
Author(s):  
Samuel Soares Valentim ◽  
Marcos Eduardo Cordeiro Bernardes ◽  
Marcelo Dottori ◽  
Matheus Cortezi
Keyword(s):  
Time Series ◽  
Sea Level ◽  
Low Frequency ◽  
Coastal Region ◽  
Complete Removal ◽  
Sao Paulo ◽  
Northern Coast ◽  
São Paulo ◽  
Monthly Time Series ◽  
Study Results

Sea level (SL), wind, air temperature (AT) and sea surface temperature (SST) variations in the coastal region of Ubatuba, northern coast of São Paulo, are assessed. A Lanczos-square cosine filter, with a 40-hour window, was applied over the SL time series between 1978 and 2000, except for the period comprising 1984 to 1986. In order to study subtidal effects on mean sea level (MSL), SL numerical filtering indicated that there was a virtually complete removal of semidiurnal and diurnal astronomical tidal components over the period of study. Results indicated an average raw SL rise of 2.3 mm/year, whereas average filtered MSL was of the order of 0.7 mm/year. Despite the overall positive MSL trend, the lunar nodal cycle of 18.6 years seemed to be the explanation for the SL series pattern. Correlations between MSL and parallel wind had a maximum correlation coefficient around 0.6, with 99% statistical confidence, while MSL and perpendicular wind correlations were not statistically significant. These results may be explained by Ekman dynamics. Data records of AT and SST between 1990 and 2003 showed positive trends for both variables. During this period, AT rose about 0.087 ºC /year for the raw series and 0.085 ºC /year for the monthly time series, and SST showed a rise of 0.047 ºC /year and 0.046 ºC/year, for the raw and monthly time series, respectively. The monthly climatology for both AT and SST showed higher values in February with 27.79 ºC and 28.59 ºC for AT and SST, respectively, and the lowest in July with 21.12 ºC for AT and 21.91 ºC for SST.

scholarly journals Correlation analysis of exports of manufactured products and basic products in the State of São Paulo

2018 ◽  
Vol 9 (5) ◽  
pp. 640
Author(s):  
Gabriel Nery da Silva
Keyword(s):  
Linear Regression ◽  
Correlation Analysis ◽  
National Economy ◽  
Strong Correlation ◽  
Sao Paulo ◽  
The State ◽  
São Paulo ◽  
Simple Linear Regression ◽  
Statistical Calculation ◽  
Manufactured Products

Participation in international trade has been important for national economy and keeps increasing over the years, and it may be noted by the importation and exportation activities. In this sense this study aims ­­to verify whether there is correlation between exports of manufactured and basic products in the State of São Paulo, as well as between them and time. Therefore it was used data available at Ministério da Indústria, Comércio Exterior e Serviços (MDIC) website relating to the amount in US$ of both manufactured products and basic products exported in the State of São Paulo from 2006 to 2016. The analysis was performed by using simple linear regression statistical calculation, aiming to verify whether there is correlation. Findings indicate there is strong correlation between the exports of basic products and time; there is no correlation between the exports of manufactured products and time; there is no correlation between the exports of basic products and the exports of manufactured products. Findings may help practitioners in forecasting demands as well as the understanding about exports behaviors when making-decisions.

scholarly journals Intra-urban differentials of fetal mortality in clusters of social vulnerability in São Paulo Municipality, Brazil

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lays Janaina Prazeres Marques ◽  
Zilda Pereira da Silva ◽  
Bárbara Laisa Alves Moura ◽  
Rossana Pulcineli Vieira Francisco ◽  
Marcia Furquim de Almeida
Keyword(s):  
Birth Weight ◽  
Linear Regression ◽  
Prenatal Care ◽  
Social Vulnerability ◽  
Causes Of Death ◽  
Sao Paulo ◽  
Fetal Mortality ◽  
São Paulo ◽  
Stillbirth Rate ◽  
The City

AbstractThis study aimed to analyze the distribution of stillbirths by birth weight, type of death, the trend of Stillbirth Rate (SBR), and avoidable causes of death, according to social vulnerability clusters in São Paulo Municipality, 2007–2017. Social vulnerability clusters were created with the k-means method. The Prais-Winsten generalized linear regression was used in the trend of SBR by < 2500 g,  ≥ 2500 g, and total deaths analysis. The Brazilian list of avoidable causes of death was adapted for stillbirths. There was a predominance of antepartum stillbirths (70%). There was an increase in SBR with the growth of social vulnerability from the center to the outskirts of the city. The cluster with the highest vulnerability presented SBR 69% higher than the cluster with the lowest vulnerability. SBR ≥ 2500 g was decreasing in the clusters with the high vulnerability. There was an increase in SBR of avoidable causes of death of the cluster from the lowest to the highest vulnerability. Ill-defined causes of death accounted for 75% of deaths in the highest vulnerability area. Rates of fetal mortality and avoidable causes of death increased with social vulnerability. The trend of reduction of SBR ≥ 2500 g may suggest improvement in prenatal care in areas of higher vulnerability.

scholarly journals "Grow and multiply": social development, birth rates and demographic transition in the Municipality of São Paulo, Brazil, time-series for 1901-94

1998 ◽  
Vol 1 (1) ◽  
pp. 61-78 ◽  
Author(s):  
José Leopoldo Ferreira Antunes
Keyword(s):  
Time Series ◽  
Mortality Rate ◽  
Demographic Transition ◽  
Social Research ◽  
Forecast Error ◽  
Historical Analysis ◽  
Sao Paulo ◽  
Infant Mortality Rate ◽  
São Paulo ◽  
The City

This study reports the construction of time-series related to standardized mortality rate, proportional mortality ratio of Swaroop and Uemura, infant mortality rate, fetal death rate, expectation of life at birth and birth rate for the city of São Paulo, SP, Brazil, from 1901 to 1994. In order to determine the structural variation of these measures, the model, forecast and correlation of these series were submitted to statistical analysis. The results obtained were compared to the historical analysis of the major socioe-conomic phenomena during this period in an effort to explain populational movements in the city, with emphasis on the slow and late nature of the process of demographic transition in the city. It was concluded that time-series analysis for demographic measures is efficient in many ways: by allowing the application of statistical methodology to the human sciences, by passing the difficulties inherent in the characteristics of these values (serial correlation, heteroscedasticity, multicollinearity and non-normality of forecast error distribution), by integrating quantitative analysis with the historical interpretation of the phenomena approached, by projecting estimates of future trends on the basis of the behavior of the variables analyzed, and by systematizing the methodology for application in future studies of social research.

scholarly journals A Forecast Combination Framework with Multi-Time Scale for Livestock Products’ Price Forecasting

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Liwen Ling ◽  
Dabin Zhang ◽  
Amin W. Mugera ◽  
Shanying Chen ◽  
Qiang Xia
Keyword(s):  
Time Scale ◽  
Geometric Mean ◽  
Forecast Combination ◽  
Short Term ◽  
Forecast Performance ◽  
Short Term Forecast ◽  
Superior Result ◽  
Combination Methods ◽  
Term Forecast ◽  
Livestock Products

China’s livestock market has experienced exceptionally severe price fluctuations over the past few years. In this paper, based on the well-established idea of “forecast combination,” a forecast combination framework with different time scales is proposed to improve the forecast accuracy for livestock products. Specifically, we combine the forecasts from multi-time scale, i.e., the short-term forecast and the long-term forecast. Forecasts derived from multi-time scale introduce complementary information about the dynamics of price movements, thus increasing the diversities within the modeling process. Moreover, we investigate a total of ten combination methods with different weighting schemes, including linear and nonlinear combination. The empirical results show that (i) forecast performance can be remarkably improved with this novel combination idea, and short-term forecast model is more suitable for the products with a relatively high volatility, e.g., mutton and beef; (ii) geometric mean, which provides a nonlinear combination, is the most effective one among all the combination methods; and (iii) variance-based weighting scheme can yield a superior result compared to the best individual forecast, especially for the products such as egg and beef.

scholarly journals Space-temporal dynamics of limnological variables in a floodplain wetland located at Ribeira do Iguape Valley (São Paulo, Brazil) at different hydrological periods

2012 ◽  
Vol 24 (1) ◽  
pp. 83-96 ◽  
Author(s):  
Roseli Frederigi Benassi ◽  
Rogério Herlon Furtado Freire ◽  
Maria do Carmo Calijuri
Keyword(s):  
Temporal Dynamics ◽  
Principal Component ◽  
Inorganic Phosphorus ◽  
Sao Paulo ◽  
Total Alkalinity ◽  
São Paulo ◽  
Dissolved Phosphorus ◽  
Conservation Policies ◽  
Spatial Gradients ◽  
Physical And Chemical Variables

AIM: The main goal of this research was to investigate the influence of the hydrological pulses on the space-temporal dynamics of physical and chemical variables in a wetland adjacent to Jacupiranguinha River (São Paulo, Brazil); METHODS: Eleven sampling points were distributed among the wetland, a tributary by its left side and the adjacent river. Four samplings were carried out, covering the rainy and the dry periods. Measures of pH, dissolved oxygen, electrical conductivity and redox potential were taken in regular intervals of the water column using a multiparametric probe. Water samples were collected for the nitrogen and total phosphorus analysis, as well as their dissolved fractions (dissolved inorganic phosphorus, total dissolved phosphorus, ammoniacal nitrogen and nitrate). Total alkalinity and suspended solids were also quantified; RESULTS: The Multivariate Analysis of Variance showed the influence of the seasonality on the variability of the investigated variables, while the Principal Component Analysis gave rise in two statistical significant axes, which delimited two groups representative of the rainy and dry periods. Hydrological pulses from Jacupiranguinha River, besides contributing to the inputs of nutrients and sediments during the period of connectivity, accounted for the decrease in spatial gradients in the wetland. This "homogenization effect" was evidenced by the Cluster Analysis. The research also showed an industrial raw effluent as the main point source of phosphorus to the Jacupiranguinha River and, indirectly, to the wetland; CONCLUSIONS: Therefore, considering the scarcity of information about the wetlands in the study area, this research, besides contributing to the understanding of the influence of hydrological pulses on the investigated environmental variables, showed the need for adoption of conservation policies of these ecosystems face the increase anthropic pressures that they have been submitted, which may result in lack of their ecological, social and economic functions.

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