NuSpace

NuSpace is the official repository platform of the National University of Science and Technology that enables researchers in:

  • obtaining easy access to a wide range of academic materials,
  • promoting knowledge dissemination and facilitating interdisciplinary collaboration.

Explore our repository to discover a wealth of knowledge across various disciplines.

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Now showing 1 - 5 of 12

Recent Submissions

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Fuzzy PI Based Motor Speed Control using DSP TMS320F2812
(International Journal of Latest Research in Humanities and Social Science (IJLRHSS), 2022) Chasokela, D.
Alternating Current (AC) induction machine plays an important role in the entire industry and daily life. This is due to their robustness, inexpensive and easy to maintain in a period of time. Vector control is used in large numbers in the speed control of AC induction machine. High dynamic performance high speed precision and wide constant torque range capabilities are the key benefits of vector control. Stability of the system during transient process and a wide range of operation are assured through the application of vector control. The purpose of this thesis is to study the vector control of AC induction machine based on the principles of the AC speed control system, vector control and fuzzy Proportional integral (PI) control, and implementing the digital vector control systems based on the digital signal processor (Digital Signal Processor-DSP TMS320F2812) from Texas Instruments. The mathematical modeling of the AC induction motor and the principles of vector control and fuzzy systems are overviewed first. Fuzzy PI regulator is then proposed to carry out the regulation of the motor speed. The fuzzy PI is an intelligent technique that has evolved in the last decades and it emulates the human way of thinking. Therefore the fuzzy PI does not need the exact mathematical model. In-depth study of fuzzy PI and the normal PI was carried out. Matlab/Simulink software is used to simulate the vector control of the AC induction motor with both fuzzy PI regulator and normal PI regulator for comparative purposes. Simulation results showed that fuzzy PI has a better performance in terms of stability, faster response and robustness, and the fluctuation ripples are also smaller. Experiments had been done on the laboratory platform of AC drive system with the help of AC speed control monitor program designed in Laboratory Virtual Instrument Engineering Workbench (LabVIEW) under variable operating conditions. The experimental waveforms were captured using the LabVIEW monitoring software. In order to carry out real time implementation, Code Composer Studio and SEEDXDS510plus Emulator are adopted to programming and testing with the DSP TMS320F2812. Experiments results show that the fuzzy PI regulator performs better than normal PI regulator, as fuzzy PI regulator indicates better waveforms of torque and speed responses during acceleration and deceleration, especially when the motor is operating on lower speeds.
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Exploring the feasibility of Research Data Management services in Zimbabwean academic libraries: the case of Zimbabwe School of Mines
(Library Philosophy and Practice, 2022) Machimbidza, T.; Mutula, S.; Ndiweni, M.
The study applied an adapted Technology, Economic, Legal, Organisational, and Schedule (TELOS) model to explore the feasibility of Research Data Management (RDM) at the Zimbabwe School of Mines (ZSM). The study employed a qualitative approach. Data were collected through interviews that were held with purposively chosen professionals at ZSM in the form of the Information Technology (IT) manager, the Librarian, and three (3) Assistant Librarians. Findings show that ZSM does not currently meet the TELOS model feasibility test. ZSM lacks a robust technological system to support data creation, data collection and description, data storage, archiving and preservation, data access, data discovery and analysis, and data reuse and transformation. ZSM has not yet created a legal environment conducive for the introduction of RDM. It does not have policies and standards in place to handle issues such as intellectual property, copyright, data licensing, ethics, data protection, freedom of information, and confidentiality. While librarians at ZSM possess basic IT and computer skills they lack skills specific for RDM. The study informs the shaping of policies, practices, and strategies regarding the introduction of RDM services in Zimbabwean academic libraries.
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Fostering Assistive Technology (at) Education and Training of Academic Library Professionals in Zimbabwe
(International Information & Library Review, 2022-05-19) Munyoro, J.; Machimbidza, T.; Mutula, S.
The study examines the forms of structured Assistive Technology (AT) education and training available to library professionals in Zimbabwe, focusing on in-service training delivered within organizations, pre-service training offered in colleges/universities and technologybased training delivered by AT vendors/suppliers. The study employs a qualitative research design. Data were collected using interviews conducted with a sample of 13 academic library staff drawn from selected universities in Zimbabwe. The websites of institutions of interest also provided vital data to supplement interview data. The study draws attention to key intervention areas in the fostering of AT education and training of library professionals in Zimbabwe. It contributes to ongoing discussion on the improvement of AT provision in developing countries’ academic libraries.
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Alignments and Mismatches of Policies on Children with Learning Difficulties/Disabilities to Professional Practice Expectations in Zimbabwe: A Reality Check
(American Journal of Educational Research, 2021-08-04) Tlou, F.N.; Nyoni, T.
The problem of gross discrepancies between educational inclusive policy rhetoric for learners with disability and applicability of such intentions in implementation has raised concerns of stakeholders in Zimbabwe. This paper examines whether or not policy prescriptions by the Zimbabwe Ministry of Primary & Secondary Education (MoPSE) for the primary level learners with difficulties are aligned or mis-aligned to actual implementation actions that are a reality on the ground. The paper interrogates these issues with regards to provision of specialised support services, checking if these are fulfilled for learners with disabilities, and argues that if they do not occur, then learning is impeded. The study was located in the interpretive paradigm which used a qualitative approach and a case study design. Participants were drawn from the Metropolitan Provincial Psychological Services team, Parents of children from one selected school and a head of school in the same Province. Results showed that while to a limited extent the specialists identified a few children in the province as falling in the learning difficulties category, the greater number was not identified. Of those identified, specialists hardly serviced them because of lack of resources and this constituted a mismatch of the pronounced claims with what is happening. The paper advances calls for advocacy for policies to be suitably aligned to the expectations purported in ministry claims.
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Lending Technologies, Firm Characteristics and Small Business Efficiency in South Africa
(Economies, 2022-11-18) Mbedzi, E.; Simatele, M.
Internal factors of Small, Micro and Medium Enterprises (SMMEs) determine their technical efficiency, while external funding characteristics improve the quality of internal factors. Since the type of lending institutions and lending technologies primarily influence the lending decisions of financial institutions, firms’ technical efficiency may be linked to such external factors. Literature on determinants of the technical efficiency of SMMEs mainly focuses on internal factors excluding the financial access paradigm which stifles the effectiveness of internal factors on technical efficiency. Based on a sample of 321 randomly selected SMMEs from Eastern Cape Province in South Africa, the study measures technical efficiency using Data Enveloping Analysis and differentiates technical efficiency among firms using Post Hoc Test Pairwise Comparisons derived from factorial ANOVA. Both main and interaction effects were captured in the analysis. Our results, which pinpoint four main findings, show technical efficiency paths followed by firms vary significantly as a result of both internal and external factors. In particular, the effects of other factors are amplified by race. As a consequence, three main contributions emerge from the study.