College of Science

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Now showing 1 - 5 of 146
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    Flood control and assessment of Accra using the weap hydrological model
    (January, 2018) Anderson, Ekow Akyen;
    The increase in the frequency and intensity of flood in some parts of Greater Accra Region is becoming a matter of great concern to the entire nation due to its negative effects on the development of the region. These floods have over the years been attributed to numerous factors including; climate change, urbanization, poor drainage systems, sea level rise and over population. The study used Water Evaluation and Planning (WEAP) hydrological model to estimate the surface runoffs for the sub-basins and also to find the correlation between Standardized Precipitation Index (SPI) and the historical flood events in Greater Accra. The study also determined the surface runoffs generated within each sub-basin. The WEAP model was used to generate surface runoff from 1990 to 2040 taking 1990 as the base year. ArcGIS 10.3 was used to delineate eight sub-basins and thereafter deter mined the characteristics of the sub-basins. Rainfall normalization was performed using the Standardized Precipitation Index and the results were verified against historical flood events for the basin over the study period. The model output was compared to observed stream flow measurement. In general a good correlation of 0.81 and 0.71 were obtained for correlation coefficient and coefficient of determination respectively. The study re vealed that, a minimum rainfall of about 60 mm would cause flood across all the eight (8) sub-basins. Also, extreme rainfall with SPI of 1.5 or more would cause flood in Greater Accra. The month of June was found to produce the highest volumes of surface runoff while December generated the least volumes of surface runoff with average runoffs of 2.4 ii× 106 m3 and 1.0 × 106 m3 respectively. It was confirmed from the research that, higher volumes of rainfalls in the sub-basins generates higher surface runoffs and therefore there are higher tendencies for floods to occur when rainfalls are high.
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    Detection and mitigation security threats in cloud systems
    (JULY 2019) Ayitey, Addy Andrene Nii
    Clouds systems provide computation and storage services to organizations and individuals with improved flexibility and low cost. Cloud customers hire resources in the form of virtual machines (VMs) within the cloud. However, these VMs may face various security threats. In this paper, three scenarios were created using RIVERBed simulation tool to detect and mitigate potential security threats targeting cloud systems. The primary objective of these scenarios is to evaluate the performance of database and web application under three different scenarios (no firewall, firewall and firewall blocking the web traffic). To demonstrate how these three scenarios can enhance cloud security, where there is no firewall, another scenario where firewall is created to filter database and web application packets and the third scenario is made to block the web traffic across the cloud. The performance metrics selected at the three levels (global level, node level and link level) is used to evaluate the performance for the database and web application from the simulations using two applications the database and web application, it is seen that the database application performance is improved when the web traffic is blocked. Even against the packet latency and the security policies the database point to point utilization is enhanced.
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    Measurement of television white space spectrum in the Central region of Ghana
    (NOVEMBER, 2018.) Quansah, Daniel Kwame Kwansah;
    Recent studies on efficient TV frequency spectrum used have proven that TV frequency spectrum in most geographical areas (especially the rural areas) are under utilized. These significant researches have shown that, the amount of frequency spectrum which is under-utilized in the TV bands is much larger than the spectrum available for use by current unlicensed user applications and services. TV White Space is an emerging concept of technology that has emanated while studying the effective utilisation and efficient management of the TV spectrum in various regions of the world. Studies have also shown that the actual unutilized frequency spectrum available varies significantly from one geographical area to another spatially as well as temporally. For this reason, TV white space estimation has been done in countries like the United States (US), the United Kingdom (UK), Europe, and Japan but unfortunately in Ghana, to the best of the authors’ knowledge no such work has been done. This thesis presents the very first effort of estimation of the amount of available TV white spaces in the Central Region of Ghana. In this study, TVWS is used as a tool for effective utilisation and efficient management of frequency spectrum. The very first localized geolocation database for TVWS in Central Region of Ghana is presented. Comparative analysis of Wi-Fi and TVWS networks revealed that Wi-Fi in the absence of strong interference from its environment works better in LoS networks while TVWS works better in the NLoS network mode. Also signal strength tests performed has shown that geographical features of a location and weather elements can have significant effect on the quality of signal strength. Finally, a proposed hybrid method for the protection of incumbent spectrum users and WSD from interference is demonstrated.
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    Assessing the prevalence and risk factors of neural tube defects at the Komfo Anokye Teaching Hospital, Kumasi
    (JUNE 2019) Ankwah, Yaa Konadu;
    Neural tube defect (NTD) is caused by folic acid deficiency, hereditary, lifestyle, environmental factors and chromosomal abnormalities, and among others it is a remarkable public health burden. However, the documented Ghana health literature is devoid of research studies on prevalence and causes of NTD in Kumasi Metropolis. This study therefore assessed the prevalence and risk factors of NTD at the Komfo Anokye Teaching Hospital (KATH) in Kumasi. The participants in this study were mothers of both live babies with and without NTDs born between the period of January, 2012 to December, 2016. The study collected both primary and secondary data from 65 mothers of babies born with NTD and 65 mothers of babies born without NTD at the Mother and Baby Unit (MBU) of KATH. The secondary data were collected from the medical records of the babies with NTD and their mothers while primary data were collected through administration of structured questionnaire. The data were analyzed quantitatively with the help of SPSS version 21.0. The study found out that the prevalence of NTD at KATH was 2.63 per 1000. The commonest type of NTD diagnosed was Meningocele. As mothers advanced in age the likelihood of neural tube defects significantly decreases. Mothers in urban communities had significantly less likelihood to give birth to babies with neural tube defects than mothers in rural communities. Single mothers had higher likelihood of giving birth to babies with neural tube defects than married mothers. Mothers with lower educational level had higher likelihood of giving birth to babies with neural tube defects. Folic acid intake before pregnancy (one year before pregnancy) reduced the likelihood of giving birth to babies with neural tube defects. Mothers in the test group were diagnosed of anaemia and eclampsia more than mothers in the controlled group. Gestational diabetic mothers exposed to smoke from firewood and anemic mothers living in dusty environment had highly significant likelihood of giving birth to babies with NTD. Pregnant women should be educated on nutrition and healthy life style at healthcare facilities as part of their antenatal. Pregnant women should also be made aware of their risk factors to help them know how to interact with the environment to prevent the occurrence of NTDs. Ministry of Health should further embark on massive folic acid intake education to help reduce the occurrence of NTDs.
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    A parametric model for estimating force of infection for hepatitis B-case study Komfo Anokye Teaching Hospital
    (October 20, 2019) Opoku-Addo, Emmanuel Kwame;
    Serological data are increasingly being used in monitoring the transmission of infec tious deseases. The aim of this study is to estimate the age-dependent force infection for patients show ing symptoms of hepatitis B virus (HBV). A secondary data was obtained from the serology department at the Komfo Anokye Teaching Hospital (KATH,January 2013- June 2016). A total of 18,528 blood donors and people coming to the serology department to test for antigen in the blood voluntarily. Linear and quadratic age-dependent logits models was suitable for the mean preva lence of HBV, with a significant negative linear and positive quadratic effect respec tively. From the results, the prevalence increase from a lower age to age 40 decrease at a higher ages and the estimated force of infection (FOI) is higher at lower ages de creasing to age 26 and increases to age 52. In conclusion, the prevalence of HBV is higher at age 40 and the FOI is lower at 26 but higher at ages 2 and 52.