Ounongo Repository

The Ounongo Repository (OR) is the institutional repository of Namibia University of Science and Technology. Ounongo means "knowledge. in the Oshiwambo and Otjiherero languages. The OR is administered by the Library, with technical assistance from DICT, and its aim is to collect, organize, manage, store, preserve, publish and make accessible worldwide, the knowledge assets or intellectual output of the University's researchers, staff and post-graduate students. Users may set up RSS feeds to be alerted to new content.


Recent Submissions

The assessment of UAV-based multispectral imagery to monitor lichen-dominated biological soil crusts response to fog and disturbances, Central Namib
(Namibia University of Science and Technology, 2022-10) Nambwandja Ailly Nanguloshi
Lichen-dominated biological soil crusts (BSCs or biocrusts) are a major contributor to biodiversity and ecosystem services of desert environments. There appropriate monitoring of lichen fields of the hyperarid coastal Namib Desert is important to understanding their greater ecological functions, such as vital CO2 sinks, and for management of socio-economic land use practices (i.e. mining, tourism, off-road tracks) which destroy the endemic, fragile and slow recovering lichens. Thanks to advanced remote sensing techniques such as the use of Unmanned Aerial Vehicles (UAVs or drones), lichen fields can be monitored, whilst minimising the environmental impact of traditional ground-based ecological research, as well as overcoming challenges in monitoring lichens with the satellite datasets, piloted aircraft. The objectives of this study was to assess the effects of hourly sunshine intensity on the use of UAV-based multispectral imagery for monitoring lichen-dominated biological soil crusts in the hyper-arid Central Namib Desert. We then assess the applications UAV-based NDVI to observe lichen photosynthetic activity response to moisture input, topography and disturbances, as well as to assess the influence of micro-topography and disturbances in off-road tracks on lichen coverage. We tested the performance of UAV-based Parrot Sequoia multispectral sensor by acquiring time series flights from 08:00 to 17:00 during a fog day. Time series of radiometrically and atmospherically corrected and uncorrected multispectral image datasets (i.e. reflectance images and vegetation indices) were compare it to solar elevation. Influence of brightness effects in sample plot on image values was tested with one-way ANOVA and Tukey HSD pot-hoc test for pairwise comparisons. There was statistical significant difference in means of the sample plots with p < 0.05. We also gathered time series UAV-based NDVI images on fog and non-fog day derived the temporal patterns of lichen photosynthetic activity in responding to wet and dry conditions, overtime. These UAV observations were supported with ground cover observation of lichens. Statistical analysis was performed to determine presence of significant differences of lichen cover and NDVI response between micro-topographic habitats (i.e. ridges, windward and leeward sides of the relief), and as well in landforms such as plains, river washes and tracks. The oneway ANOVA and Student-test (t-tests), were considered significant at p < 0.05 for both UAV and ground 15 observations. Polynomial regression analysis of the relationship between elevation and ground lichen cover and NDVI was significantly correlated with p-values of < 0.05. Well illuminated good quality images can be captured at low solar elevation, in morning images at 08:00 and in the later afternoon at 17:00. Midday images taken between 10:00 and 15:00 at higher solar elevation are heavily impacted by brightness effects. The radiometrically corrected images and NDVI were more accurate than the raw uncorrected images. UAV-based NDVI can estimate photosynthetic activity when lichens are hydrated by fog or higher air humidity, as opposed to when they are desiccated and photosynthetic activity is inhibited. Elevation is good predictor lichen cover and photosynthetic activity. Lichen cover is heavily impacted by off-road tracks. The topographic attribute influence the distribution of lichen cover and lichen species diversity. This research study has provided insights into a means to monitor these sensitive environments. It also enables informed decision making to manage natural resource and regulate socio-economic land-use.
Recommending a Machine Learning Model to Detect the Fatigue State for Employees at Namdeb
(Namibia University of Science and Technology, 2024-04) Nakale, S.N.
Workplace fatigue is one of the major risk factors across different industries and it negatively impacts productivity and workplace safety. Thus, fatigue detection and monitoring is essential to promote occupational health and safety. The advancements in data collection technologies have made it possible for industries to develop data driven solutions by developing Artificial Intelligence (AI) and Machine Learning (ML) based fatigue monitoring and detection systems. The Advanced Driver Assistance Systems (ADAS) is one of the technologies that has been adopted in various industries to improve safety for drivers. Namdeb implemented the ADAS in recent years and they have identified the need for a system to detect and classify employees’ fatigue state using data from the ADAS. In this study, an ML based fatigue detection system was proposed. Facial behavioural fatigue features were used to detect fatigue. The proposed system deployed some of the commonly used ML classification algorithms and it was evaluated on a simulated dataset, the Yawning Detection Dataset (YawDD), and a real-world dataset, data from the Namdeb ADAS. The results showed that most of the supervised ML classifiers achieved a fatigue prediction accuracy above 90% for both datasets. The Random Forest (RF) based fatigue detection-based model was found to be the best model. The k-Means which is an unsupervised ML classifier exhibited the worst performance. However, the reliability and generalisability of the results based on the real-world dataset can be improved by using a larger dataset. The major challenge to developing behavioural based fatigue detection systems for real world setting like the mining environment is face detection accuracy which is affected by factors such as low image resolution due to poor and variable lighting conditions, face orientation to camera and proximity of face to the camera. The significant contribution of this study is the use of real-world dataset to test the proposed fatigue detection system. Overall, the study contributes to the promotion of the eighth Sustainable Development Goal (SDG) of promoting safe working environments.
(Namibia University of Science and Technology, 2023-05-04) KADHIKWA, SAKEUS IITA.
Internal communication has long been the lifeblood of successfully and effectively managed organizations, especially when such communication is strategically managed. Though literature has established the benefits of internal communication, especially when it comes to employee engagement, commitment, and improved corporate reputation, research assessing the strategic role of internal communication in government departments is limited. The aim of the study was to assess the strategic role of internal communication at the Ministry of Home Affairs, Immigration, Safety and Security in Namibia. To achieve this objective, four secondary objectives were pursued. The first secondary objective focused on examining the challenges faced by the Department of Home Affairs and Immigration in implementing the internal communication strategy. The second objective focused on analyzing the impact of internal communication on service delivery, while the third focused on internal communication and employee morale. The last objective examined the alignment between internal communication and the department’s strategy. Data for the study were collected using a structured interview guide. Face-to-face online were conducted with a conveniently selected sample of 25 participants. The methodology that was employed was a qualitative research approach that followed a case study research design. Several challenges affecting the effective implementation of the internal communication strategy were identified. Furthermore, it was noted that participants had mixed views about the role of internal communication and service delivery, as well as its strategic role in the organization. Based on these findings, the study makes recommendations and suggestions for future research.
Mathematical analysis of foot and mouth disease with optimal control: a case study of FMD in Namibia.
(Namibia University of Science and Technology, 2023-06) Ndeevelo, Palivamwe, Merolly
This study aims to comprehensively analyse Foot and Mouth Disease (FMD) by formulat ing two mathematical models specifically tailored for confined and unconfined environments in Namibia. The models composed for this research incorporate essential compartments that capture the intricate dynamics of livestock populations, including their susceptibility to FMD, latent exposure, infectiousness, and recovery. Furthermore, the models account for the imple mentation of optimal control measures by farmers and the disease control mechanisms em ployed by national institutions such as the vaccination campaign, culling and quarantining of livestock. To ensure the stability and equilibrium of the proposed models, well-established mathemat ical principles such as the LaSalle Invariance principle, Lyapunov function and Routh-Hurwitz stability analysis are utilized. These methods assist in determining the equilibrium points of the models and assessing their stability properties. In addition, historical data on FMD reported cases within the country is also incorporated to enhance the accuracy and applicability of the models analyses. The study utilises numerical simulations with an Ordinary Differential Equation (ODE) solver in Python to demonstrate the impact of various scenarios of FMD progression. Furthermore, an excel-input data sheet is created to facilitate basic analysis and to showcase the variability range resulting from modifications in FMD dynamics. By employing a combination of mathematical modelling, stability analysis, historical data integration, and numerical simulations, this research provides significant insights into the be haviour and control of FMD in confined and unconfined environments in Namibia. The findings vii contribute to the existing knowledge of FMD in Namibia and provide insights that can inform decision-making and policy formulation in combating this economically significant disease.
A first syntaxonomic description of the vegetation of the Karstveld in Namibia.
(Vegetation Classification and Survey/Pensoft Publishers, 2023-10-24) Strohbach, Ben J.; Strohbach, Marianne M.
Aims: The Karstveld in Namibia has been recognized as an area of high plant diversity. However, this area is also recog nised as a hotspot of various forms of degradation including bush encroachment. Minimal baseline data on the compo sition and diversity of vegetation in this area is available, therefore this paper is a first attempt to rectify this data defi ciency. Study area: The Karstveld in Namibia is formed around the Otavi Mountain Range in northern Central Namibia, consisting of strongly karstified carbonate bedrock, rising up to 2000 m a.s.l. The Karstveld includes the Ovambo Basin plains with shallow calcrete soils north of the range, up to the Omuramba Ovambo. Because of orographic effects, the area receives some of the highest rainfall in Namibia, with up to 600 mm per year. Methods: A set of 889 relevés with 868 species was selected from the GVID ID AF-NA-001 database. A partial data set, using trees, shrubs, dwarf shrubs and grasses only, was used for the classification with modified TWINSPAN. The initial result yielded four main groups, according to which the data was split and further classified. Several vegetation types observed during field surveys were not reflected in the classification results; these were refined using Cocktail with known characteristic species. Results: The four main units represented wetlands and grasslands with six associations, a Thornbush savanna – Karstveld tran sition zone with four associations, Kalahari vegetation with four associations and the Karstveld proper with eight asso ciations. The latter are grouped together as the Terminalietea prunioides, with two orders and three alliances recognised under them. We describe 16 associations according to the ICPN. Conclusions: Although the associations presented in this paper are clearly defined, there exists a high degree of diversity within these. The Karstveld is also extraordinary species rich within the context of the arid to semi-arid Namibian environment. Taxonomic reference: Klaassen and Kwembeya (2013) for vascular plants, with the exception of the genus Acacia s.l. (Fabaceae), for which Kyalangalilwa et al. (2013) was followed. Abbreviations: ga = annual grass; gp = perennial grass; GPS = Global Positioning System, referring to a hand-held ground receiver; hl = herb layer, containing all hemicryptophytes, therophytes and geophytes, but excluding grasses (Poaceae); ICPN = International Code of Phytosociological Nomenclature (Theurillat et al. 2021); MAP = mean annual precipitation; NMS = nonmetric multidimensional scaling (Kruskal 1964); RDL = Red Data List (IUCN Species Survival Commission 2001); s1 = tall shrubs, i.e. multi-stemmed phanerophytes between 1 and 5 m; s2 = short shrubs, i.e. cha maephytes or ‘dwarf shrubs’ below 1 m; SOTER = Global and National Soils and Terrain Digital Database (FAO 1993); t1 = tall trees, > 10 m; t2 = short trees, between 5 and 10 m; t3 = low trees, i.e. single-stemmed phanerophytes between 2 and 5 m; TWINSPAN = Two Way Indicator Species Analysis (Roleček et al. 2009); WGS84 = World Geodetic System, 1984 ensemble