Using sound localization to gain depth perception for the visually impaired through sensory substitution
- Authors: De Klerk, James Carmichael
- Date: 2020
- Subjects: People with visual disabilities Directional hearing--Physiological aspects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/50779 , vital:42674
- Description: The visually impaired do not have the visual ability to localize objects in three-dimensional space, rather, they rely on their other senses to gain depth perception. Sensory substitution is the concept of substituting one sense for another, normally substituting an impaired sense with a functioning sense. Visual-to-auditory sensory substitution substitutes an impaired visual sense with a functioning auditory sense. This research aimed to investigate and develop techniques for visualto-auditory sensory substitution – using sound localization as a sensory substitution for depth perception. The research started by investigating the characteristics of human audition with a particular focus on how humans localize sounds. It then looked at existing visual-to-auditory sensory substitution systems and the techniques they used. From the existing systems, a system known as MeloSee was chosen as a baseline for developing and evaluating further sensory substitution prototypes. The baseline prototype (𝑃0) was then implemented and a preliminary study performed. Based on the knowledge gained from the preliminary study, baseline implementation and the background research, a set of improvement recommendations were generated. The next iteration – Prototype 1 (𝑃1) – was then developed based on the recommendations. A comparative study between 𝑃0 and 𝑃1 was then performed. Based on the study, another set of improvement recommendations were generated. From the recommendations, a final prototype was developed – Prototype 2 (𝑃2). The last comparative study was then performed between 𝑃0 and 𝑃2, with a third set of recommendations being generated as a result. From the studies it was found that participants using 𝑃0 were able to identify when they were approaching large objects such as walls. 𝑃1 built on that, improving the ability to identify the quadrant of a nearby isolated object. 𝑃2 built on 𝑃0 and 𝑃1, achieving similar results to 𝑃1 for identifying the quadrant of nearby isolated objects, and improving on 𝑃0 and 𝑃1 with regard to depth discrimination – especially for navigation tasks where there were no obstacles. Based on the three sets of recommendations and what was learnt over the course of the research, a set of visual-to-auditory sensory substitution techniques were presented. The techniques aim to be useful for implementing visual-to-auditory sensory substitution systems, which would provide the visually impaired with the visual ability to localize objects in three-dimensional space through sound.
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- Date Issued: 2020
The relationship between electricity supply, power outages and economic growth in South Africa
- Authors: Khobai, Hlalefang
- Date: 2013
- Subjects: Economic development -- South Africa , Energy consumption -- Economic aspects
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:9024 , http://hdl.handle.net/10948/d1020069
- Description: The economic boom in South Africa following the 1994 democratisation led to increased welfare of the citizens and their purchasing power. This further resulted in increase in electricity consumption. The electricity supply did not increase proportionally to the increase in electricity consumption leading to the 2008 shortage of electricity which nearly damaged the power generating circuit. The literature review has shown that electricity supply and consumption have a positive impact on economic growth. It further showed that employment enhances economic growth. Conversely, it showed that power outages negatively affect economic growth. The research serves to investigate the relationship between electricity supply and economic growth in South Africa and to examine the impact of power outages on economic growth. It also seeks to find the appropriate structure for electricity supply industry that will lead to increase in economic growth. The autoregressive distributed lag (ARDL) bounds approach was used to find the relationship between economic growth, electricity supply, power outages and employment using quarterly data from 2000 to 2012. The ARDL technique was chosen over the conventional models such as Johansen technique for the research because it uses a single reduced form of equation to examine the long run relationship of the variables as opposed to the conventional Johansen test that employs a system of equations. The ARDL technique is also suitable to use to test co-integration when a small sample data is used and does not require the underlying variables to be integrated of similar order. The Vector Error Correction Model (VECM) Granger causality was also employed in the study to establish the causality between economic growth and electricity supply. It was chosen for its ability to develop longer term forecasting, when dealing with an unconstrained model. The results from the ARDL bounds test showed that there is a long run relationship between economic growth, electricity supply, power outages and employment. Based on the causality tests, the findings showed a unidirectional causality flowing from electricity supply to economic growth. This implies that electricity supply affect economic growth in South Africa. The results further showed no causality flowing from economic growth to electricity supply which indicates that when economic growth is booming fewer funds are used for improvement of the electricity generation. Lastly, the results showed that power outages negatively affect economic growth in the long run. To sum up, electricity supply is an important factor for economic growth in South Africa. It is therefore necessary that South Africa must put in place measures aimed at stimulating electricity supply. One of the measures aimed at increasing output of electricity is to unbundle the electricity sector. This process involves allowing entry of the Independent Power Producers (IPPs), Independent System Operator (ISO) and Regional Electricity Distributors (REDs). This will lead to increased supply of electricity and competitively lower prices of electricity. The study further recommends that renewable energy sources should be used to produce electricity instead of coal and nuclear fuels as they failed to produce enough electricity for the nation.
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- Date Issued: 2013
An exploratory study of the AmaTshezi chieftaincy conflict in Mthonjana Village, Mqanduli in the Eastern Cape, 2002-2007
- Authors: Nodada, Lubabalo Yandisa
- Date: 2011
- Subjects: Chiefdoms -- South Africa -- Eastern Cape , Xhosa (African people) -- South Africa -- Kings and rulers , Conflict of interests -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MPhil
- Identifier: vital:8258 , http://hdl.handle.net/10948/d1012345 , Chiefdoms -- South Africa -- Eastern Cape , Xhosa (African people) -- South Africa -- Kings and rulers , Conflict of interests -- South Africa -- Eastern Cape
- Description: The battle for traditional leadership successions continue to have negative effects on many Tribal Authority Councils across Africa, for example, the Valoyi Tribe, part of Tsonga/Shangaan nation in South Africa, and the Godban chieftaincy conflict in the northern town of Yendi in Ghana. Community conflicts related to chieftaincy positions across South Africa are apparent. This study was an attempt to explore and describe the dynamics of the AmaTshezi chieftaincy conflict in Mthonjana village, Mqanduli. The analysis focused on exploring the AmaTshezi chieftaincy conflict in terms of conflict and conflict process theory. This explorative study sought to explore and describe the perceptions of eight ad hoc committee members (government officials) who had been involved with attempting to resolve the AmaTshezi chieftaincy conflict. The researcher conducted extensive face-to-face interviews with these committee members and thoroughly studied the necessary documents that informed the study. Thematic data analysis revealed latent conflict, conflict emergence, conflict escalation, conflict stalemate, and conflict de-escalation, as key conflict phases in the AmaTshezi chieftaincy conflict. A number of recommendations are made about how those in authority could better manage communal conflict. The recommendations may, for instance, be used in the formulation of policies to influence better conflict management by government and help the Eastern Cape House of Traditional Leaders to manage communal conflicts better and to facilitate public education programmes about issues relating to birthright leadership positions and lineage procedures.
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- Date Issued: 2011
An investigation into the introduction of process analytical technology, using near infrared analysis, to selected pharmaceutical processes
- Authors: Naicker, Krishnaveni
- Date: 2007
- Subjects: Near infrared spectroscopy , Pharmaceutical chemistry
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10153 , http://hdl.handle.net/10948/577 , http://hdl.handle.net/10948/d1011710 , Near infrared spectroscopy , Pharmaceutical chemistry
- Description: Introduction: Process analytical technologies are systems for the analysis and control of manufacturing processes to assure acceptable end-product quality. This is achieved by timely measurements of critical parameters and performance attributes of raw material and in-process material and processes. The introduction of process analytical technology using near infrared analysis was investigated in three areas, namely incoming raw material analysis, blend uniformity analysis and moisture determination in the fluid bed dryer. Methodology: Incoming raw material identification - The FOSS XDS rapid content analyzer was used for the development of a NIR method for the identification and material qualification of starch maize and lactose monohydrate. Blend uniformity analysis – The SP15 Laboratory Blender fitted with near infrared probe was utilized for the study. Two types of blend experiments were designed to monitor the distribution of magnesium stearate (lubricant) in the blend, namely, a powder blend utilizing lactose monohydrate and a granule blend utilizing Ridaq® granule. Software methods were developed to monitor the standard deviation of the absorbance at the wavelengths that were specific for lactose monohydrate, Ridaq® granule and magnesium stearate. To confirm the prediction of end-point using near infrared, results were verified using an atomic absorption method for magnesium stearate. The blends were sampled at the selected time intervals corresponding to three states of the blend, namely, before end-point, at end-point and after end-point using a sampling plan. An additional six blends were conducted for the granule blend and sampled when the standard deviation had reached a value below 3 x 10-6 at the magnesium stearate wavelength at four consecutive data points (standard deviation value extrapolated from blends carried out to predetermined time intervals). Moisture determination in the fluid bed dryer – Moisture values for two products (Product A and Product B) were retrospectively collected from past production batches. A process capability study was conducted on the moisture values to determine if the current process was in a state of control. Results and Discussion: Incoming raw material identification – The algorithms used for the spectral library were able to distinguish between the raw materials selected. The spectral library positively identified the starch maize and lactose monohydrate samples that were not present in the library. The negative challenge with pregelatinised starch and tablettose demonstrated that the spectral library was able to differentiate between closely related compounds. Blend uniformity analysis – Blends sampled at the predetermined time intervals demonstrated a homogeneous state when the standard deviation of the absorbance was low and a non-homogeneous state when the standard deviation of the absorbance was high, thus near infrared prediction on the state of the blend was confirmed by the standard analytical methods. The series of Ridaq® granule and magnesium stearate blends sampled when the standard deviation was below 3 x 10-6 were homogeneous with the exception of one blend that was marginally out of specification. Blend durations were significantly lower than the standard blend durations used in the facility and ranged from 112 to 198 seconds. Moisture determination in the fluid bed dryer – From the process capability study of the two products it was noted that Product A is stable but can still be optimized while Product B is at a desirable state. The statistical evaluation of the moisture values for Product A and Product B demonstrated that the use of the product temperature to monitor the moisture gave consistent results. The current process is stable and capable of producing repeatable results although near infrared provides a means for continuously monitoring the product moisture and allows one to take action to prevent over-drying or under-drying. Conclusion: From the investigations conducted, it can be seen that there is definitely a niche for process analytical technology at this pharmaceutical company. The implementation is a gradual process of change, which may take time, probably several years (Heinze & Hansen 2005).
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- Date Issued: 2007