UNAM Gā-aisib Repository (University of Namibia)
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Evaluation of machine learning classification models for detecting electronic fund transfers scam SMSes
No full textA thesis submitted in partial fulfilment of the requirements for the degree of Master of Science (Information Technology)The last decade saw the emergence of mobile banking and a pervasive transcendence of spams from email to SMS communications. M-banking offers the users an ability to execute EFT transactions using mobile devices and allow them to receive SMS notifications acknowledging their transactions. While this provide convenience to m-banking users, in the wake of SMS spams it also presented vulnerabilities that could be exploited to scam money and goods from them. To execute these scams, spammers send forged EFT ( e.g. e-wallet) deposit notification SMSes to unsuspecting users, then contact and request them to do EFT payments as refunds for the supposed en-oneous deposits acknowledged by the bogus notifications. Similarly, during goods exchange, scammers use forged deposit notification SMSes to trick sellers to believe that they have paid for the goods. In Namibia, the high affordability of SIM cards and the readily available access tom-banking accounts such as e-wallet by anyone with a valid SIM number provides a favourab le operating environment for the EFT SMS scammers. Inferences from literatures on novel spam filtering techniques suggested that implementing machine learning classification could help address the EFT SMS scams problem, partly motivating this study to evaluate such application. Prevalent reporting of EFT SMS scams in local media (which mostly involves the country"s largest bank by
market share, FNB) and the observed lack of dedicated IT solutions to address such
problem were other factors that inspired this work. The study collected a dataset of
ham and EFT scam SMSes, from which machine learning features for classifying
SMSes were extracted. This was followed by a pre-evaluation to determine the features that allow ham and EFT scam SMSes to be classified optimally. SMSes comprising the collected dataset were then represented using the optimal features and used to train and evaluate Suppo1i Vector Machine, Naive Bayes and Random Forest classifiers. The evaluation results revealed that the SVM classifier was the most effective with respect to detecting EFT scam SMSes, achieving a FNR=0.00, CA=0.992, Recall= l .0 and F l-measure=0.995. The RF classifier followed with FNR=0.0 11 , CA=0.983, Recall=0.989 and F l -measure=0.989; while the NB classifier came last with FNR=0.027, CA=0.975, Recall=0.973 and F l -measure=0.983. The envisaged future work will look to use the methods, findings and conclusions drawn in this study to guide development of mobile application(s) that implement machine learning classification to detect EFT scam SMSes
Incidence of contagious Bovine pleuropneumonia in the northern regions of Namibia
No full textA 25-year retrospective study investigated the incidence of contagious bovine pleuropneumonia (CBPP) in the northern communal areas of Namibia. Throughout the study period, the proportion of bovine animals that clinically recovered following treatment of suspected CBPP infection were greater than those that died from suspected CBPP infection (71.6% and 28.4%, respectively, N=4743; z=42.16, p<.001). The proportion of unconfirmed CBPP diagnoses was greater than that of confirmed cases (65.4% and 34.6%, respectively, z=30.04, p<.001). More animals died from confirmed CBPP infection in the North Central Regions (NCR) and Zambezi region (5.4% and 4.1%, respectively) than in Kavango (East and West) and Kunene regions (2.1% and 0.5%, respectively; p<.05). Kavango regions had the greatest proportion of animals (7.9%; p<.05) that clinically recovered following treatment of confirmed CBPP infection whilst more animals in NCR and Kunene region recovered following treatment of unconfirmed CBPP (41.6% and 1.0%, respectively; p<.05). The NCR and Kunene region had greater proportions of animals that died from unconfirmed CBPP infections (9.1% and 1.0%, respectively; p<.05). More animals than expected died of confirmed CBPP in 1990, 1995, 2000, 2002, 2003 and 2004 (p<.05) whereas more animals than expected died of suspected CBPP in 1990, 1991, 1993 and 2004 (p<.05). Overall, the majority of animals died of confirmed CBPP in April, August and December (2.8%, 1.9% and 0.7%, respectively, p<.05). The highest CBPP vaccination coverage was achieved in 2003, 2004, 2009, 2011 and 2012 (96.6%, 82.6%, 84.8%, 90.1% and 90.1%; respectively). The greatest CBPP incidence rates (per 100 000) occurred in 1995, 1996, 1997, 1998 and 2003 (54.1, 43.4, 75.3, 106.2 and 25.5, respectively). The highest CBPP-related mortalities (per 100 000) occurred in 1995, 1996, 1997, 1998 and 2004 (25.3, 11.1, 17.2, 11.9 and 15.6, respectively). Although the incidence of CBPP cases has decreased, control of the disease remains a challenge because of cross-border livestock movements between northern Namibia and southern Angola
Rooting strategies of savanna shrubs in the Kalahari basin: Implications for the coexistence of woody and herbaceous plants and shrub encroachment in the African savannas
No full textA dissertation submitted in fulfilment of the requirements for the Degree of Doctor of Philosophy in GeographyThe savanna biomes are characterised by a coexistence of two antagonist – woody plants and herbaceous plants in defiance of competition theories. Scientific efforts to understand this unique coexistence are still largely inconclusive; various theories have been proposed, but no unanimous theoretical framework exists to date. Among these theories, the root niche-partitioning model offers the most popular, yet the most controversially debated viewpoint. It argues that this coexistence is a result of vertical root niche-partitioning, a natural mechanism by which woody plants develop deeper root systems to avoid competition with herbaceous plants. Despite its prominence and subsequent integration into models of species coexistence and arid eco-hydrology, several shortcomings of this model are evident. For example, it overlooks the critical issue of root plasticity. This study was thus designed to investigate the root systems of various savanna shrubs across a rainfall gradient in the Kalahari to test the aforementioned model. The overall aim was to investigate, compare, and contrast the root system architecture (RSA) of encroaching shrubs and those of non-encroaching shrubs within the proximate environmental setting. Using a direct excavation method, 183 shrubs were sampled, had their roots exposed and were subjected to morphometric measurements. Shrub encroachers were randomly selected and four non-encroaching shrubs surrounding each of the sampled encroacher plant were systematically chosen, using the nearest-neighbour approach. Results indicated that shrubs in the Kalahari develop diverse root system architecture which exhibits significant inter- and intra-species plasticity. In particular, three bush encroaching shrubs, Terminalia sericea, Senegalia mellifera, and Dichrostachys cinerea, tend to develop root systems essentially composed significantly (p < .001) of lateral roots deployed within shallow soil sub-surfaces; and partly without taproots, more especially in the drier part of the Kalahari. Overall, the architecture of the savanna shrubs’ root system can be classified into three major architecture groups: i) a fibrous or lateral root system, ii) a dual root system, and iii) a taproot system. These architecture groups are not necessarily unique to any species or environment, which suggests that plants develop their root systems plastically in response to prevailing environmental conditions. These findings are not consistent with the premise that the savanna shrubs are largely deep-rooted. This oversight has major implications for our current understanding of the savanna biomes. Whereas deeper-rooted shrubs may allow for root niche-partitioning with grasses, shallow-rooted shrubs are potentially in direct competition with grasses, suggesting that shrub encroachment is a probable manifestation of this competition. These findings may also explain why the phenomenon of shrub encroachment is largely attributed to shallow-rooted shrubs such as T. sericea
Causes, dynamics and financial losses associated with red offal condemnation at a beef abattoir in Namibia
No full textThere are limited studies on red offal condemnations and financial implications at high throughput abattoirs in Namibia. Causes of condemnation, temporal distributions and financial losses associated with red offal condemnations at a beef abattoir in Namibia from 2016 to 2018 were investigated. A total of 39157 red offal valued at N364 805) were condemned following the slaughter of 251697 cattle. Condemnations were dependent on year [X2(14) = 587.13, p<0.001], month [X2(77) = 1898.72, p<0.001] and season [X2(7) = 111.12, p<0.001] of study. Overall, 2016 had the most and 2018 the least condemnation of red offal (38.73% and 23.22%, respectively; p<0.05). Most red offal condemnations (13.34%, p<0.001) were recorded in June, with livers and lungs as the most condemned organs (54.32% and 29.88%, respectively; p<0.001). The highest condemnations were caused by miscellaneous causes (abscesses and hematomas) followed, in descending order, by inflammatory, parasitic and bacterial causes and contaminations (38.3%, 29.4%, 16.6% and 15.8%, respectively, p<0.05). Liver condemnations varied with the year and season of study [X2(20) = 1834.02, p<0.001 and X2(9) = 1010.43, p<0.001; respectively], as were lung condemnations according to pathological condition [X2(12) = 492.43, p<0.001 and X2(6) = 45.84, p<0.001; respectively]. The occurrence of hydatidosis in the summer and pneumonia in winter was greater than expected (15.1% and 4.3%; respectively, p<0.05). A substantial loss of revenue to the abattoir due to the condemnation of livers and lungs was determined. Meat inspection served as a control point for hydatidosis.University of Namibi
Analysis of the determinants of exchange rate volatility in the SACU region
No full textA thesis submitted in partial fulfillment of the requirements for the Degree of Master of Science in EconomicsThe currencies of the five SACU countries have experienced notable volatility in the
last decade. The purpose of this study therefore, was to identify the determinants of
exchange rate volatility in the SACU region and also to determine ifthere is a long run relationship between exchange rate volatility and its determinants. The study used annual time series data from 1980 to 2017. This study uses the generalised
autoregressive conditional heteroscedasticity GARCH (1 , I) approach. The results
from the study revealed that interest rates and inflation were both significant factors in explaining exchange rate volatility in Lesotho. Interest rates were also found to be a determinant of exchange rate volatility in Namibia. For South Africa, Swazi land and Botswana, inflation and interest rates were not significant in explaining exchange rate volatility. Policy makers in the region should therefore start considering the possibility of macro-economic policy independence going forward . In Lesotho, targeted inflation may go a long way in reducing exchange rate volatility. In Namibia and Lesotho, there is also room to explore the possibility of changing the interest rates time and again with the aim of reducing exchange rate volatility
An exploration of life crisis experiences of employed and unemployed early adults in Windhoek, Namibia
No full textA mini thesis submitted in partial fulfillment of the requirements for the Degree of Masters of Arts in Clinical PsychologyThe aim of this study was to explore life crises prevalence of both employed and unemployed early adults in Windhoek, Namibia, by comparing differences in life crisis reporting between them. The study also aimed to determine gender differences in life crisis experiences of early adults, if any, and also the areas in which life crisis was most experienced. Guided by a quantitative approach, an Adult Crisis Episode Retrospective Self-Assessment Tool (ACERSAT) was used to collect the data. Snowball sampling and simple random sampling methods were used to select the employed and unemployed participants respectively. A total sample of 186 early adults participated, of which ninety-five (95) were officially employed and ninety-one (91) were unemployed. The data obtained were analysed through SPSS version 25.0 using descriptive statistics such as frequencies and percentages. A Chi-Square test of Independence was also conducted to determine if there was any significant relationship between life crisis reporting, occupation status, and gender. Overall, 82.8% of the sample conceded to experiencing an early adult life crisis. The employed participants reported more life crisis than the unemployed participants by 7.2%. Males reported a greater incidence of life crisis than females by 5.7% and most life crises reported were related to the career and/or family categories. No significant association was found between life crisis, occupation status and gender. The results indicated a prevalence of early adult life crisis experiences, especially amongst employed males. Career and family were the areas surrounding the majority of the reported life crisis. Therefore, it is recommended for secondary and tertiary level life skills education to include developmental psychology to better prepare early adults for prospective life crisis experiences. It is further recommended that future studies should address coping strategies for this group and possible post-crisis growth
Optimation of Ontaku/ Oshikundu: Pearl millet and sorghum malts quality and conveniet premix development
No full textA research dissertation submitted in fulfillment of the requirements for the Degree of Doctor of Philosophy in Science (Biochemistry)Oshikundu/Ontaku is a nonalcoholic, acidic, opaque fermented beverage. It is comprised of pearl millet (Pennisetum glaucum (L.) R. Br) meal/flour, commonly known as mahangu, malts of pearl millet or sorghum (Sorghum bicolour (L.) Moench) and/or brans (pearl millet). Brewing of oshikundu remains an art in households with no empirical improvement of a controlled fermentation flow process to give a consistent product. Some of the major limitations to the formal commercialisation of this brew are the absence of standardised malting process that gives a consistent malt quality and microbial safety. The lack of standard
ingredient ratios (flour/meal: malt: water) of brewing. Also, the sedimentation of adjunct particles at the bottom (dreg), thus creating the difference in viscosity of oshikundu. Welldefined fermenting microorganisms are not used, and the preparation method still relays on a laborious time-consuming process. Therefore, this study investigated conditions for malting, reduction of dreg, identification of fermenting microorganisms and formulation of ingredient ratio for an improved preparation process. Grains used in the study were collected from Omahenene Agricultural Research Station (20 15 harvest), of the Ministry of Agriculture,
Water and Forestry. Pearl millet varieties Okashana 2 (SDMV 93032), Kantana (landrace) and Kangara (SDMV 92040), while sorghum varieties are Macia (SDS3220) and landrace commonly referred to as red sorghum. Malts of the two cereals were prepared by steeping in static water at 20-22°C for 2 hours wet and 2 hours air-rest for a total of 8 hours and germinated at 30°C. Malts were dried between 50-55°C for 24 hours. Cereals germinative energy was above 90% as recommended for sorghum by the European Brewery Convention. Malting loss was high up to 30% in pearl millet varieties and Macia. Crude protein and fibre
were found . to increase following malting. Reducing sugars were not detected in
nongerminated pearl millet graiJ.'ls. Malts reducing sugars were statistically significant (p ~0.05) between cereals. The malt reducing sugars was as follows Macia> Red sorghum> time reduce dregs. Also, ingredient ratios were formulated by the use of dry ingredients premix for making oshikundu that was easy to prepare
The return of the sacred stones of the Ovambo kingdoms: Restitution and the revision of the past
No full textThe discourse of restitution often takes place within the framework of the ‘ethics of collecting’ with a focus on the return of objects violently obtained, which has restricted the debate. This case study of the return of two sacred stones from Finland to Namibia reflects on the cultural impact of their return. Largely Christianized communities re-encountered objects that were sacred and central to earlier belief systems. We argue that the role of the sacred stones changed over time in ways that challenge any assumption of stasis that might be assumed when deploying the concept of ‘tradition’. The return of the two stones provoked renewed interest in pre-Christian rituals but also efforts to strengthen the position of ‘traditional authorities’ in relation to the democratic system of governance in Namibia. The ripples of restitution illustrate the wider importance of the return of cultural artefacts for stimulating contemporary cultural and political debate
A literary exploration of ethnocentric segregation and discrimination in Bessie Head's Maru and Gasebalwe Seretse's The Pursuit of Xhai
No full textA thesis submitted in partial fulfilment of the requirements for the Degree of Master of Arts in English StudiesThis literary thesis explored ethnocentric segregation and discrimination in Bessie Head’s Maru and Gasebalwe Seretse’s The Pursuit of Xhai. The purpose of the study was to investigate the causes and effects of ethnocentric segregation and discrimination amongst ethnic groups as presented in the selected novels. The study was primarily a qualitative desktop research whereby two novels were purposefully selected and analysed. This analysis was informed by the integrated or intergroup threat theory. Integrated or intergroup threat theory posits that perceptions of threat are significant when considering prejudice and discrimination towards non-dominant groups. It focuses particularly on the conditions that led to perceptions of threat, which in turn have an impact on attitudes and behaviour. In addition, if individuals feel threatened during an intercultural interaction, including fear of being rejected, embarrassed, ridiculed or exploited by out-group members, unfavourable attitudes towards out-groups are likely to occur. The findings of this study revealed that the Masarwa people appear to be active in eradicating segregation and discrimination by keeping their cultural pride and applying their natural talent of communicating to Mother Earth in escaping danger. Although at some points they were victimised as a low filthy nation and untouchable to the locals, their natural beauty and intelligence brought a bond of a good and loving relationship with the superior ethnic groups. On the other hand, the non-Masarwa people who were against ethnic segregation and discrimination amongst ethnic groups managed to overcome all the challenges from their counterparts. They supported the Masarwa people and protected them warmly in every chaotic situation that occurred. This study recommends that further research should be done to analyse how the Namibian writers portrayed ethnocentric segregation and discrimination in literary genres and further research should also be conducted in other genres of African literature to explore the theme of ethnocentric segregation in Africa
Investigating the effects of government expenditure and money supply on unemployment in Namibia
No full textA thesis submitted in partial fulfilment of the requirements for the Degree of Master of Science in EconomicsOver the years, Namibia continue to experienced rapid growth of unemployment. The purpose of this study is to investigate the effects of government expenditure and money supply on unemployment in Namibia. The annual data employed in the study covered the period from 1980 to 2018. The study applied the ARDL or bound cointegration approach which is said to be more appropriate for the estimation of small sample studies and variable combination of the order of integration (I (0) and I (1)). Granger causality tests were also performed in the study to establish existence of causality between the variables used in the models. The empirical results established cointegration relations between unemployment, government expenditure, money supply and inflation in Namibia. The results further indicated that both government expenditure and money supply have an impact on unemployment in the country. A negative and statistically significant at 5 per cent relationship was observed between government expenditure and unemployment as well as between money supply and unemployment at 10 per cent level of significant. Evidence of short-run causality between government expenditure and unemployment as well as between money supply and unemployment was also found. Finally, the study recommends that for an effective combat of the unemployment problem in Namibia, there is a need for the government to focus on investment, employment generation and provide basic business enhancing facilities such as stable power supply, water and operational facilities to trickle down to the masses