List of Titles

Quick View

Assessing the vulnerability of inland fisheries to human-induced perturbation in Lake Kariba fishery, Zambia

- Imikendu, Imbwae

Authors: Imikendu, Imbwae
Date: 2024-10-11
Subjects: Uncatalogued
Language: English
Type: Academic theses , Doctoral theses , text
Identifier: http://hdl.handle.net/10962/466725 , vital:76774 , DOI https://doi.org/10.21504/10962/466725
Description: Inland fisheries play a critical role in providing nutrition, employment, and ensuring food security among vulnerable groups in Lake Kariba. However, their value is usually undermined in developmental plans, and their contribution to a broader economic development is often undervalued. Over the past two decades, inland fisheries have stagnated. Simultaneously, there have been wide reports of increased fishing effort and declining trends in commercially valuable fish species. This has resulted into a wide socio-economic and environmental problems in various fishing communities. Lake Kariba Zambia, exemplifies this sustainability challenge, where fisheries resources and livelihoods are interlinked. A systematic peer review paper on this topic was documented, published and used for analytical work, focusing on governance and how it affects the utilization of the fisheries resources for food security and biodiversity conservation. This study had four major objectives: (i) to identify threats to fisheries’ productivity in Lake Kariba; (ii) to understand the socio-economic and environmental conditions of small-scale fisheries in Lake Kariba; (iii) to determine adaptation strategies adopted by small-scale fishers in light of the changing socio-economic and environmental conditions in Lake Kariba; (iv) to determine how management of fisheries has to change in response to the wide socio-economic and environmental challenges in the region. Using Ostrom’s framework for analysing socio-ecological systems, various socioeconomic and environmental problems faced by fishing communities in Lake Kariba were examined to devise a sustainable fisheries management plan. The study employed explorative surveys, household questionnaires, key informant interviews, focus group discussions, observations, and a review of literature to elicit secondary data. A proportional quota sampling technique was used to draw a representative sample of 300 small-scale fishers and a typology was developed using a bivariate analysis. Chi-square was used to determine fishing effort over time. Using a curve fitting estimation regression test, a trend analysis in fish production for the past thirteen years (13) years was performed. Results did not show a significant decline in fish production over the past 13 years, yet experts and the fishers reported declining trends in valuable fish species. The finding of this study provides both practical and theoretical lessons that can enhance adaptive capacity and support sustainable livelihoods in the region. A fisheries sector policy is urgently required to guide governance process and coordinate a multi-sectoral perspective to fisheries management if socio-economic progression is to be attained. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2024
Full Text:
Date Issued: 2024-10-11

Quick View

Self-attentive vision in evolutionary robotics

- Botha, Bouwer

Authors: Botha, Bouwer
Date: 2024-04
Subjects: Evolutionary robotics , Robotics , Neural networks (Computer science)
Language: English
Type: Master's theses , text
Identifier: http://hdl.handle.net/10948/63628 , vital:73566
Description: The autonomy of a robot refers to its ability to achieve a task in an environment with minimal human supervision. This may require autonomous solutions to be able to perceive their environment to inform their decisions. An inexpensive and highly informative way that robots can perceive the environment is through vision. The autonomy of a robot is reliant on the quality of the robotic controller. These controllers are the software interface between the robot and environment that determine the actions of the robot based on the perceived environment. Controllers are typically created using manual programming techniques, which become progressively more challenging with increasing complexity of both the robot and task. An alternative to manual programming is the use of machine learning techniques such as those used by Evolutionary Robotics (ER). ER is an area of research that investigates the automatic creation of controllers. Instead of manually programming a controller, an Evolutionary Algorithms can be used to evolve the controller through repeated interactions with the task environment. Employing the ER approach on camera-based controllers, however, has presented problems for conventional ER methods. Firstly, existing architectures that are capable of automatically processing images, have a large number of trained parameters. These architectures over-encumber the evolutionary process due to the large search space of possible configurations. Secondly, the evolution of complex controllers needs to be done in simulation, which requires either: (a) the construction of a photo-realistic virtual environment with accurate lighting, texturing and models or (b) potential reduction of the controller capability by simplifying the problem via image preprocessing. Any controller trained in simulation also raises the inherent concern of not being able to transfer to the real world. This study proposes a new technique for the evolution of camera-based controllers in ER, that aims to address the highlighted problems. The use of self-attention is proposed to facilitate the evolution of compact controllers that are able to evolve specialized sets of task-relevant features in unprocessed images by focussing on important image regions. Furthermore, a new neural network-based simulation approach, Generative Neuro-Augmented Vision (GNAV), is proposed to simplify simulation construction. GNAV makes use of random data collected in a simple virtual environment and the real world. A neural network is trained to overcome the visual discrepancies between these two environments. GNAV enables a controller to be trained in a simple simulated environment that appears similar to the real environment, while requiring minimal human supervision. The capabilities of the new technique were demonstrated using a series of real-world navigation tasks based on camera vision. Controllers utilizing the proposed self-attention mechanism were trained using GNAV and transferred to a real camera-equipped robot. The controllers were shown to be able to perform the same tasks in the real world. , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2024
Full Text:
Date Issued: 2024-04

Quick View

The nature of Visual Representations of multiplication and division exercises in nine Grades 1 to 3 South African textbooks

- Booysen, Tammy Irene

Authors: Booysen, Tammy Irene
Date: 2023-03-29
Subjects: Mathematics Textbooks , Mathematics Study and teaching (Elementary) South Africa , Visual learning , Multiplication Study and teaching (Elementary) South Africa , Division Study and teaching (Elementary) South Africa , Constructivism (Education)
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/422579 , vital:71959
Description: Mathematics is a language that is rich in visual representations (Mudaly & Rampersad, 2010). Visual Representations assist us in developing our reasoning skills when solving a problem and our understanding of the relationships between concepts (Ozkan et al., 2018). This thesis focuses on the different visual representations (VR) in South African Foundation Phase mathematics textbooks and workbooks. Textbooks and workbooks play an important role in developing an understanding of mathematical concepts for both teachers and learners (Harries & Spooner, 2000). While teachers generally rely heavily on textbooks, they were a key resource while schools were closed due to COVID-19 lockdown regulations. The theory of Constructivism forms part of the theoretical framework for this study. Constructivism advocates that learners actively construct knowledge through experiences rather than passively receiving knowledge from the outside (Von Glaserfeld, 2001). Vygotsky believed that social interactions create experiences that facilitate the learning and meaning-making process (Vygotsky, 1978). This case study is underpinned by an interpretivist paradigm as it sought to examine the nature of VRs in three Grades 1 - 3 textbooks/workbooks. My research approach is primarily qualitative with descriptive statistics to assist in developing a more comprehensive understanding of the research questions. The study was guided by the analytic tool designed by Fotakopoulou and Spiliotopoulou (2008) which I adapted for Foundation Phase mathematics use. The framework provides insight on the type of VR, VRs relation to content, VRs relation to reality, the function of the VR and dimensionality of a VR. While the workbooks had many more VRs than textbooks, the dominant type of VR in textbooks and workbooks are images. The VRs mostly have a strong relation to content with a realistic relation to reality as they were predominantly 2D representation of a 3D object that had an exemplifying function (type b). , Thesis (MEd) -- Faculty of Education, Education, 2023
Full Text:
Date Issued: 2023-03-29

Quick View

The development of teachers’ pedagogical content knowledge (PCK) in the mediation of chemical equilibrium: A formative interventionist study

- Manamike, Tasara

Authors: Manamike, Tasara
Date: 2022-10-14
Subjects: Chemical equilibrium , Chemistry Study and teaching (Secondary) Nambia , Expansive learning , Career development Nambia , Professional learning communities Nambia , Pedagogical content knowledge , Cultural-historical activity theory
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/405300 , vital:70159
Description: Persistent student errors in understanding chemical equilibrium as shown by poor student achievement in national examinations reflect student difficulties in learning and deficiencies in teaching methodologies. Studies which have been conducted in Namibia have explored the teaching of chemical equilibrium and revealed that teachers seem not to have adequate pedagogical content knowledge (PCK) for mediating chemical equilibrium and therefore there is a need for continuing professional development (CPD). However, it seems the CPD facilitators also find this topic difficult and are unsure of which methods are really effective owing to the disagreements among teachers and researchers. In addition, current CPD practices ostensibly fail to address the teachers’ needs because the facilitators have their own commitments and accountabilities and may ignore teachers’ contexts. It is against this backdrop that I conducted this formative interventionist study to improve teachers’ PCK for mediating chemical equilibrium through expansive learning (learning something that does not yet exist). A blend of the interpretivist and critical paradigm underpinned this study, which assumed a transactional epistemology. The qualitative case study research design was used to gather in-depth information about the multiple realities of the participants, bearing in mind that teaching is idiosyncratic, and the teaching approaches or strategies employed heavily depend on the contexts. Accordingly, the cultural historical activity theory was used to guide the teachers’ activities during the intervention for generating the data which were analysed using the topic-specific pedagogical content knowledge. The study revealed that the participants faced challenges in their teaching, namely: (i) students’ difficulties with comprehension and (ii) teachers’ instructional problems or deficiencies in instructional skills. The findings also revealed that the intervention enabled the participants to collectively transform their practices and therefore address the major challenges in their practices, that is, they expansively learnt how to effectively teach chemical equilibrium. , Thesis (MEd) -- Faculty of Education, Education, 2022
Full Text:
Date Issued: 2022-10-14

Quick View

Showing items 1 - 7 of 7