University of Dar es Salaam Research Repository
The Research Repository of University of Dar es Salaam (UDSM) is the online/digital collection of research and publications from University of Dar es Salaam. The Research Repository UDSM collects preserves and makes available publications and conference papers, journals, books and other outputs created by UDSM researchers. Participation in UDSM Research Repository helps to ensure that publications are more visible and highly cited.
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Recent Submissions
Kavenuke, P., & Kinyota, M. (2023). Gender Inequalities in Higher Education in Tanzania: Investigating theInfluence of Parents’ Socio-Economic Status. Paper in Education and Development, 41(2), 39-57.
(UDSM, 2023-12-31) KINYOTA MJEGE; PATRICK SEVERINE KAVENUKE
This study investigated the extent to which gender inequality manifests in higher education in Tanzania. Furthermore, through a gendered lens, the study investigated the influence of parents’ socioeconomic status on gender inequality among students who major in STEM and teacher education programmes. The study used a sample of 1714 students across four higher education institutions. It was found that gender is an aspect that forms inequality. For instance, the study revealed that gender differences were reflected in our sample, where female students were underrepresented in both STEM majors and teacher education majors. Also, parents’ education, occupation, educational background (in STEM), and income are some of the socioeconomic statuses that reinforce gender inequality. Finally, the implications for future research and policy are discussed.
Nonlinear anisotropic diffusion methods for image denoising problems: Challenges and future research opportunities
(Elsevier, 2023-03-01) Maiseli, Baraka
Nonlinear anisotropic diffusion has attracted a great deal of attention for its ability to simultaneously remove noise and preserve semantic image features. This ability favors several image processing and computer vision applications, including noise removal in medical and scientific images that contain critical features (textures, edges, and contours). Despite their promising performance, methods based on nonlinear anisotropic diffusion suffer from practical limitations that have been lightly discussed in the literature. Our work surfaces these limitations as an attempt to create future research opportunities. In addition, we have proposed a diffusion-driven method that generates superior results compared with classical methods, including the popular Perona–Malik formulation. The proposed method embeds a kernel that properly guides the diffusion process across image regions. Experimental results show that our kernel encourages effective noise removal and ensures preservation of significant image features. We have provided potential research problems to further expand the current results.
Overview of optimal operations of renewable energy power systems in microgrid and virtual power plants
(Elsevier, 2023-11-23) Mushi, Aviti Thadei; Mnkeni, Godwin Elinazi; Justo, Jackson John; Mwasilu, Francis Avilus; Mwinyiwiwa, Bakari Mohamedi Mfaume
Renewable energy sources (RES) in microgrids and virtual power
plants are considered to be the backbone of these power systems. The
RESs have been shown recently to reduce the costs per kWh by 85% in
South Africa, some viability to electrify airport in Tanzania [1,2], and rural
villages [2 4] Some reported case studies show that investing in the same
project five years later has a great impact on running costs [5] and can
improve electrification rates as some other technologies can [6 8]. The
RESs in microgrid configuration are considered to be the most costeffective power solutions to meet the load requirements of people that
live in rural areas [9,10].
Overview of Renewable Energy Power System Dynamics
(Elsevier, 2023-11-23) Mushi, Aviti Thadei; Suwi, Owdean; Justo, Jackson John
Depletion of fossil fuel, global warming, and environmental pollution
clarify the importance of renewable energy sources (RESs). Renewable
energy is derived from the Earth’s natural resources that are not finite or
exhaustible, especially during human lifetime. Renewable resources include
biomass energy (such as ethanol), microbial fuel cell [1], hydropower,
geothermal power, wind energy, and solar energy [2]. Offline solar photovoltaic (PV) can power rural villages [3 5], or airports [6] at an equitable
levelized cost of energy (LCOE) if the wind is not enough to give economies of scale [7 9].
MPPT DC-DC Buck-Boost Converter for Off Grid Hybrid Solar-Wind-Battery System in Ikuza Island, Tanzania
(Tanzania Journal of Engineering and Technology (TJET), 2023-11-14) Nassoro, Nassoro Sadick; Msigwa, Consalva Joseph; Mushi, Aviti Thadei; Mwinyiwiwa, Bakari M.M.
Ikuza Island in Kagera-Tanzania faces lack of electricity due to cost challenges of extending the grid by marine cables and other transmission facilities. These makes such endeavour not appealing to the supply authority due to those higher charges. Therefore, this paper undertakes to design hybrid renewable energy sources for the island by specifically focusing on the buck-boost converter for the energy conversion from these renewable resources. The design of the bidirectional buck-boost converter for maximum power point tracking in off-grid hybrid renewable energy systems is multifaceted due to the inhomogeneity nature of the renewable energy sources. The bidirectional buck-boost converter, solar PV, wind-based generator, and energy storage system are designed and simulated in MATLAB/Simulink software. The designed system is tested with varying solar irradiance (750 to 1000 W/m2), temperature (20 to 25C) and wind speed (150 to 157.5 radians/s) at constant load of 260 A while load variation involved varying the load current from 0 to 260 A at solar irradiance, temperature, and wind speed of 1000 W/m2, 25 C and 157.5 radians/s, respectively. The variation of DC link bus voltage at different load conditions is reported. The simulation results show that the designed converter is able to maintain DC link voltage at 600 V. Moreover, the DC link voltage shows a maximum drop of approximately 0.67% during the constant load condition. Contrarily, a significant improvement is observed when the designed converter operates with the hybrid system of solar PV, PMSG-based wind generator and with energy storage system.