Tag Archives: Estimation

Mapping of land cover and estimation of their emissivity values for gas flaring sites in the Niger Delta (Published)

This study examines the changes in land cover (LC) types at 6 gas flaring sites in Rivers State, Niger Delta region of Nigeria; and to estimate their emissivity (Ɛ) values. 15 Landsat scenes (3 Landsat 5 Thematic Mapper (TM) and 12 Landsat 7 Enhanced Thematic Mapper Plus (ETM+)) from 17 January 1986 to 08 March 2013 with < 30 % cloud contamination were used. All the sites are located within a single Landsat scene (Path 188, Row 057). Radiometric calibration of the multispectral bands of the data, and atmospheric correction for multispectral bands using dark object subtraction (DOS) method was carried out. The first unsupervised cluster analysis of the atmospherically corrected reflectance (bands 1-4) using the K-mean function of the MATLAB tool was carried out. The results obtained give 3 classes of LC type and cloud as the 4th class. The second cluster analysis was performed with the cloud-masked reflectance (bands 1-4) to give vegetation, soil, built up area and water LC types for all flaring sites. This was confirmed through the fieldwork observation for ground validation of Landsat 5 TM and Landsat 7 ETM+ in the Niger Delta that LC types obtained from satellite data are the same with those observed during the fieldwork. The method used to estimate Ɛ value for LC types at these sites is based on the Ɛ of 4 LC types present at each site. The changes in LC differ throughout the period for the 6 sites due to different human activities within each site. The Ɛ values estimated for the 4 LC types for the sites are not stable but changing from 1986 to 2013 due to changes in LC types. The results of LC classification show that K-mean method can distinguish up to 4 LC types very well in the Niger Delta.   

 

Keywords: Estimation, Gas-flaring, Land Cover, Mapping, Niger-Delta, emissivity

On The Comparison of Some Methods of Allocation in Stratified Random Sampling for Skewed Population (Published)

A study to evaluate and compare some methods of allocation in stratified random sampling suitable for the estimation of population total of a skewed population was carried out in this paper. We looked at three methods of allocation in the above scheme namely; Optimum allocation, N-proportional allocation, and variable (X) proportional allocation methods. We investigate the condition under which one method of allocation is better than the other using three sets of real life data on staff and student enrolment, collected from the record of the Teaching Service Commission (TESCOM) Oyo State Nigeria. The third set of data is on Income and expenditure of Industrial and General Insurance (IGI) Plc.   We found out that optimum allocation is the least and the best despite variation observed in the sizes of nh within the strata.  

Keywords: Allocation, Estimation, Sampling, Skewness, Stratification

Mathematical Concept of Area; a Tool for Mathematical Quantification and Estimation (Published)

The study seeks to investigate the effect of a good knowledge of mathematical concept of area on the quantification and estimation of tiles in a building construction. To achieve the purpose of this study, one null hypothesis was formulated. An experimental design was adopted for this study. A Sample of ten (10) tillers who attained primary education was collected from a building construction site. This was divided into two groups of five (5) tillers each, the experimental group tillers taught with mathematics concept of area) and the control group (tillers taught area without mathematics concept of area). The instrument for data collection was workers ability on quantification and estimation test (WAQET), with reliability index of 0.87. The hypothesis was tested using the independent t-test analysis at p>O.O5 level of sigi4flcance, the result showed a mean score of (10. 09) of the experimental group which was higher than the mean score of (8.02) for the control group. The analysis reveals that tillers who had a good knowledge of mathematical concept of area were better in quantification and estimation of tiles.

Keywords: Area, Construction, Estimation, Mathematics, Quantification