Browsing by Author "Daudi, Emmanuel"

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    Characterization and prediction of the GPS derived total electron content over the Eastern part of the African sector.
    (University of Dar es Salaam, 2018) Daudi, Emmanuel
    The purpose of this study was to investigate the behavior of the ionosphere over the eastern part of the African sector and develop a model for TECv prediction over the region. Data used were from the Africa array and IGS network of ground based dual-frequency GPS receivers from eighteen (18) stations within the eastern part of the African sector for 2012 and 2013, and for NN modeling, data for 2014 to 2016 were also included in the study. The network array covers approximately the area from 17°S to 12°N in geographical latitude (magnetic lat. ~2.6oN to ~26.9oS) and from 26°E to 40°E in geographical longitude (magnetic long. ~95oE to ~112oE). Stations at equatorial region were used for comparison purposes. The results showed that, the variations of TECv over the region were complex and irregular especially during afternoon hours and varied from day to day without remarkable variation pattern, and were more evident during equinox months than during solstice months. The post noon maxima vary differently from one season to another and the period of time occupied by the day maximum is larger with increasing latitude. TECv varied semiannually, and the day maximum value increases from the stations in low latitudes and decreases significantly with the increasing latitudes. Generally, the IRI-2012 model was observed to overestimate the GPS-TECv, and IRI-2001 overestimated GPS-TECv more compared with other options. GPS-TECv values and IRI-TECv values showed good correlation (above 0.8) at most of time and the TECv using IRI-neq and IRI-01- corr had small PRMSE from the GPS measured TECv compared to the IRI-2001. It was further observed that, TECv was enhanced on the storm day reaching its maximum value at around the mid-day, and strong reductions in TECv were also depicted from the stations that are located far from the equatorial region from around 13 – 20 hours (UT). For the developed model based on NN, it was established that, when the NmF2 is added as an input neuron to the model, the optimal results was obtained. This was archived when the hidden layer of 18 neurons was used. The developed model predicted the GPS TECv more accurate compared to IRI-2012 model with NeQuick topside Ne option.
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    The relationship between social-emotional skills and academic achievement among primary school students in Kinondoni Municipality, Tanzania
    (University of Dar es Salaam, 2017) Daudi, Emmanuel
    Social-emotional skills are considered as important factors in child development, and specifically they play a central role in determining child academic success. Nevertheless, the association of social-emotional skills and academic achievement in the Tanzanian context remains largely unexplored. This study examined the relationship between social-emotional skills and academic achievement among primary school students in selected schools in Tanzania. The study was quantitative guided by correlation design. Furthermore, it employed questionnaire and cognitive tests as data collection instruments. Data were collected from 401 students, with 197 males and 204 females. Students’ level of social-emotional skills was measured by using the social-emotional competence scale, which was originally developed by Ming Zhou and Jessie Ee. Students ‘academic achievement was measured by using Kiswahili and Mathematics cognitive tests. Data were analyzed descriptively by running frequencies to determine the level of social-emotional skills among respondents. Furthermore, data were analyzed inferentially where various analysis tests were conducted such as independent t-test to compare the level of social-emotional skills between high performing public primary schools and low performing public primary schools. Furthermore, multiple regressions were conducted to test the effect of demographic variables such as sex and socioeconomic status on social-emotional skills. Finally, Pearson product moment of correlation was conducted to determine the statistical relationship between social-emotional skills and academic achievement. The results showed that the majority of respondents reported a reasonable moderate and high level of social-emotional skills. Nevertheless, there was no statistical significant relationship between social-emotional skills and academic achievement implying that social-emotional skills did not influence academic achievement. This study could be replicated indifferent contexts to assess if there could be circumstances under which social-emotional skills could have a relationship with academic achievement. There is also a need for future studies to conduct a qualitative study for the purpose of developing a contextually relevant scale that is responsive to the Tanzanian cultural context. This is because social-emotional skills are embedded in a social-economic cultural context of a country.
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    A study of variations of the Earth’s magnetic field over Dar es Salaam
    (University of Dar es Salaam, 2013) Daudi, Emmanuel
    The purpose of this study was to determine the diurnal and seasonal variations of the earth’s magnetic field and occurrence of magnetic storms over Dar es Salaam. The data used in this study were from records of geomagnetic variations measured by a fluxgate-type magnetometer installed at University of Dar es Salaam (395007’12”E and 6024’00”S). The instrument with a noise level of 0.02 nT recorded magnetic field components H, D and Z. It recorded both one – second and one-minute data sets. In this case, one-minute data sets. In this case, one-minute data set averaged hourly was used. The hourly means were plotted against local time of each day and analysed for each month to determine the diurnal variations. The seasonal variations were analysed using daily means, as well as the monthly means. Identification of the magnetic storms was done from the plots of daily variations for each day of the month. The severity of each storm observed was categorized using the K-index. From the analysis done, in most of the days, the H component followed a normal pattern of having a single maximum near midday and almost constant during the night. The D component had a morning minimum and afternoon maximum; Z component varied differently, in some days it showed a maximum at around noon, and in other days it showed a minimum. In the analysis of seasonal variations, components H and Z showed and increase from January to December, while component D increased from January to April, and then decreased constantly to December. During the study period, eight storms were recorded and observed to occur irregularly. Three of them were major, and five were minor ones. It is recommended that, future research that incorporates longer period’s data and from other observatories should be carried out for comparison purposes.