Price discovery in the cryptocurrency option market : a univariate GARCH approach
- Venter, Pierre J., Mare, Eben, Pindza, Edson
- Authors: Venter, Pierre J. , Mare, Eben , Pindza, Edson
- Date: 2920
- Subjects: GARCH , Option pricing , Cryptocurrencie
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/442546 , uj:38608 , Pierre J. Venter , Eben Mare & Edson Pindza | (2020) Price discovery in the cryptocurrency option market: A univariate GARCH approach, Cogent Economics & Finance, 8:1, 1803524
- Description: Abstract: , In this paper, two univariate generalised autoregressive conditional heteroskedasticity (GARCH) option pricing models are applied to Bitcoin and the Cryptocurrency Index (CRIX). The first model is symmetric and the other takes asymmetric effects into account. Furthermore, the accuracy of the GARCH option pricing model applied to Bitcoin is tested. Empirical results indicate that asymmetry is not an important factor to consider when pricing options on Bitcoin or CRIX, this is consistent with findings in the literature. In addition, the GARCH option pricing model provides realistic price discovery within the bid-ask spreads suggested by the market.
- Full Text:
- Authors: Venter, Pierre J. , Mare, Eben , Pindza, Edson
- Date: 2920
- Subjects: GARCH , Option pricing , Cryptocurrencie
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/442546 , uj:38608 , Pierre J. Venter , Eben Mare & Edson Pindza | (2020) Price discovery in the cryptocurrency option market: A univariate GARCH approach, Cogent Economics & Finance, 8:1, 1803524
- Description: Abstract: , In this paper, two univariate generalised autoregressive conditional heteroskedasticity (GARCH) option pricing models are applied to Bitcoin and the Cryptocurrency Index (CRIX). The first model is symmetric and the other takes asymmetric effects into account. Furthermore, the accuracy of the GARCH option pricing model applied to Bitcoin is tested. Empirical results indicate that asymmetry is not an important factor to consider when pricing options on Bitcoin or CRIX, this is consistent with findings in the literature. In addition, the GARCH option pricing model provides realistic price discovery within the bid-ask spreads suggested by the market.
- Full Text:
An early numeracy intervention for first-graders at risk for mathematical learning difficulties
- Pirjo Aunio, Korhonenb, Johan, Ragpot, Lara, Törmänen, Minna, Henning, Elizabeth
- Authors: Pirjo Aunio , Korhonenb, Johan , Ragpot, Lara , Törmänen, Minna , Henning, Elizabeth
- Date: 2021
- Subjects: Early numeracy , Executive functions , Intervention
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/459298 , uj:40828 , Citation: Pirjo A. et al. 2021. An early numeracy intervention for first-graders at risk for mathematical learning difficulties. Early Childhood Research Quarterly 55 (2021) 252–262.
- Description: Abstract: The aim of this study was to investigate whether early numeracy skills of South African first graders who are at-risk for mathematical learning difficulties can be improved with an intervention program. The participants were 267 children from 17 classrooms in the greater Johannesburg area. In this quasi- experimental small group intervention study (15 sessions over 5 weeks) the outcome measure was early numeracy skills. Based on pretest early numeracy scores, the children were divided into an intervention group (N = 40), a low performing control group (N = 32), and an average performing control group (N = 195). The main result was that the intervention group had improved more in numerical relational skills, compared to low-controls; this effect remained statistically significant after controlling for executive functions, language skills and kindergarten attendance, and was also observable in the delayed post- measurement. Executive functions, language skills and kindergarten attendance all predicted the level of early numeracy skills at the beginning of the intervention, but only executive functions explained individual differences in counting skills development from pre- to delayed posttest.
- Full Text:
- Authors: Pirjo Aunio , Korhonenb, Johan , Ragpot, Lara , Törmänen, Minna , Henning, Elizabeth
- Date: 2021
- Subjects: Early numeracy , Executive functions , Intervention
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/459298 , uj:40828 , Citation: Pirjo A. et al. 2021. An early numeracy intervention for first-graders at risk for mathematical learning difficulties. Early Childhood Research Quarterly 55 (2021) 252–262.
- Description: Abstract: The aim of this study was to investigate whether early numeracy skills of South African first graders who are at-risk for mathematical learning difficulties can be improved with an intervention program. The participants were 267 children from 17 classrooms in the greater Johannesburg area. In this quasi- experimental small group intervention study (15 sessions over 5 weeks) the outcome measure was early numeracy skills. Based on pretest early numeracy scores, the children were divided into an intervention group (N = 40), a low performing control group (N = 32), and an average performing control group (N = 195). The main result was that the intervention group had improved more in numerical relational skills, compared to low-controls; this effect remained statistically significant after controlling for executive functions, language skills and kindergarten attendance, and was also observable in the delayed post- measurement. Executive functions, language skills and kindergarten attendance all predicted the level of early numeracy skills at the beginning of the intervention, but only executive functions explained individual differences in counting skills development from pre- to delayed posttest.
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Procurement planning factors influencing the quality performance of primary healthcare building facilities : a mediation effect of the firm’s business partnership
- Gambo, Nuru, Musonda, Innocent
- Authors: Gambo, Nuru , Musonda, Innocent
- Date: 2021
- Subjects: Partnership , Procurement , Healthcare
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/463736 , uj:41397 , Citation: Gambo, N., Musonda, I. 2021. Procurement planning factors influencing the quality performance of primary healthcare building facilities: A mediation effect of the firm’s business partnership, Cogent Engineering, 8:1, 1872823, , DOI: 10.1080/23311916.2021.1872823
- Description: Abstract: The paper reports on an assessment of the mediation effect of a firm’s business partnership on procurement planning factors influencing the quality performance of primary healthcare building facilities. A quantitative data collection approach was adopted in the study using structured questionnaires circulated to 520 respondents comprising project managers in the Nigerian construction industry. A stratified proportionate random sampling method was used for the selection of respondents which yielded 370 responses and 357 were used for analysis. Findings were that procurement planning factors influenced the quality performance of primary healthcare building facilities, and the firm’s business partnerships mediate the relationship between procurement factors and quality performance of primary healthcare building facilities. This study serves as awareness to governments and other stakeholders in the construction industry on the provision of quality primary healthcare building facilities by leveraging a firm’s business partnership as a mediating factor...
- Full Text:
- Authors: Gambo, Nuru , Musonda, Innocent
- Date: 2021
- Subjects: Partnership , Procurement , Healthcare
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/463736 , uj:41397 , Citation: Gambo, N., Musonda, I. 2021. Procurement planning factors influencing the quality performance of primary healthcare building facilities: A mediation effect of the firm’s business partnership, Cogent Engineering, 8:1, 1872823, , DOI: 10.1080/23311916.2021.1872823
- Description: Abstract: The paper reports on an assessment of the mediation effect of a firm’s business partnership on procurement planning factors influencing the quality performance of primary healthcare building facilities. A quantitative data collection approach was adopted in the study using structured questionnaires circulated to 520 respondents comprising project managers in the Nigerian construction industry. A stratified proportionate random sampling method was used for the selection of respondents which yielded 370 responses and 357 were used for analysis. Findings were that procurement planning factors influenced the quality performance of primary healthcare building facilities, and the firm’s business partnerships mediate the relationship between procurement factors and quality performance of primary healthcare building facilities. This study serves as awareness to governments and other stakeholders in the construction industry on the provision of quality primary healthcare building facilities by leveraging a firm’s business partnership as a mediating factor...
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Reflections on human rights education from the orphans and vulnerable children (OVC) sector in Mozambique
- Authors: Burnett, Cora
- Date: 2021
- Subjects: Civil society , Human rights education , Poverty
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/463841 , uj:41410 , Citation: Burnett, C. 2021. Reflections on human rights education from the orphans and vulnerable children (OVC) sector in Mozambique, Cogent Social Sciences, 7:1, 1860275, DOI: 10.1080/23311886.2020.1860275 , DOI: https://doi.org/10.1080/23311886.2020.1860275
- Description: Abstract: Human Rights Education (HRE) often forms the cornerstone of addressing human rights issues at the local level where nongovernmental bodies in partnership with human rights agencies deliver various initiatives. Such agencies mostly operate from a neo-colonial framework as addressing structural and political power struggles limits addressing structural transformation for most vulnerable populations. There is a gap in the existing literature about the sense-making of such roles and responsibilities related to a local agency that speaks to active citizenship and youth as agents of change. This paper examines the effects of HRE associated with Freire’s emancipatory education on youth in the impoverished community of Trevo in Mozambique. Within this impoverished community, orphans and vulnerable youth makes up one of the lowest socio-economic strata that was targeted as the research population for this study. The research question addresses how such vulnerable youth make sense of HRE and how do they apply the learnings in an authentic and realistic way. A local nongovernment organisation (NGO) implemented the Bons Vizinhos (Good Neighbours) programme where children and youth received human rights’ training. Three executive members, two implementers and six youth took part in semi-structured interviews (primary data), whilst 21 posters from youth as part of a photo-voice activity were re-interpreted and thematically categorised (secondary data). Vulnerable populations socially construct their understandings of what they consider “safe” and “unsafe” spaces. HRE practitioners need to draw on these insights to make learning meaningful.
- Full Text:
- Authors: Burnett, Cora
- Date: 2021
- Subjects: Civil society , Human rights education , Poverty
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/463841 , uj:41410 , Citation: Burnett, C. 2021. Reflections on human rights education from the orphans and vulnerable children (OVC) sector in Mozambique, Cogent Social Sciences, 7:1, 1860275, DOI: 10.1080/23311886.2020.1860275 , DOI: https://doi.org/10.1080/23311886.2020.1860275
- Description: Abstract: Human Rights Education (HRE) often forms the cornerstone of addressing human rights issues at the local level where nongovernmental bodies in partnership with human rights agencies deliver various initiatives. Such agencies mostly operate from a neo-colonial framework as addressing structural and political power struggles limits addressing structural transformation for most vulnerable populations. There is a gap in the existing literature about the sense-making of such roles and responsibilities related to a local agency that speaks to active citizenship and youth as agents of change. This paper examines the effects of HRE associated with Freire’s emancipatory education on youth in the impoverished community of Trevo in Mozambique. Within this impoverished community, orphans and vulnerable youth makes up one of the lowest socio-economic strata that was targeted as the research population for this study. The research question addresses how such vulnerable youth make sense of HRE and how do they apply the learnings in an authentic and realistic way. A local nongovernment organisation (NGO) implemented the Bons Vizinhos (Good Neighbours) programme where children and youth received human rights’ training. Three executive members, two implementers and six youth took part in semi-structured interviews (primary data), whilst 21 posters from youth as part of a photo-voice activity were re-interpreted and thematically categorised (secondary data). Vulnerable populations socially construct their understandings of what they consider “safe” and “unsafe” spaces. HRE practitioners need to draw on these insights to make learning meaningful.
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The interrelationship between internal marketing, employee perceived quality and customer satisfaction – a conventional banking perspective
- De Bruin, Leigh, Roberts-Lombard, Mornay, De Meyer-Heydenrych, Christine
- Authors: De Bruin, Leigh , Roberts-Lombard, Mornay , De Meyer-Heydenrych, Christine
- Date: 2021
- Subjects: Internal marketing , Service quality , Customer satisfaction
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/463768 , uj:41401 , Citation: De Bruin, L.. Roberts-Lombard, M., De Meyer-Heydenrych, C. 2021. The interrelationship between internal marketing, employee perceived quality and customer satisfaction – a conventional banking perspective, Cogent Business & Management, 8:1, 1872887 , DOI: https://doi.org/10.1080/23311975.2021.1872887
- Description: Abstract: This study explores how internal marketing influences employees’ perceived ability to deliver service quality in the conventional banking industry in Oman. The influence of employee perceived service quality on customer satisfaction is also established. Data was obtained from retail banking branch employees at the customer front line of conventional banks in Oman using electronic surveys. A total of 355 responses were obtained for data analysis. The measurement and structural models were measured through structural equation modelling. The findings reveal that internal price, internal promotion, and internal performance management are influencers of service quality, with the latter having a direct relationship with customer satisfaction. In addition, service quality has a positive influence on customer satisfaction in conventional banks in Oman. The findings can guide conventional banking management in Oman on how internal marketing can promote service quality, ultimately leading to positive customer satisfaction experiences.
- Full Text:
- Authors: De Bruin, Leigh , Roberts-Lombard, Mornay , De Meyer-Heydenrych, Christine
- Date: 2021
- Subjects: Internal marketing , Service quality , Customer satisfaction
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/463768 , uj:41401 , Citation: De Bruin, L.. Roberts-Lombard, M., De Meyer-Heydenrych, C. 2021. The interrelationship between internal marketing, employee perceived quality and customer satisfaction – a conventional banking perspective, Cogent Business & Management, 8:1, 1872887 , DOI: https://doi.org/10.1080/23311975.2021.1872887
- Description: Abstract: This study explores how internal marketing influences employees’ perceived ability to deliver service quality in the conventional banking industry in Oman. The influence of employee perceived service quality on customer satisfaction is also established. Data was obtained from retail banking branch employees at the customer front line of conventional banks in Oman using electronic surveys. A total of 355 responses were obtained for data analysis. The measurement and structural models were measured through structural equation modelling. The findings reveal that internal price, internal promotion, and internal performance management are influencers of service quality, with the latter having a direct relationship with customer satisfaction. In addition, service quality has a positive influence on customer satisfaction in conventional banks in Oman. The findings can guide conventional banking management in Oman on how internal marketing can promote service quality, ultimately leading to positive customer satisfaction experiences.
- Full Text:
'Are principals instructional leaders yet?' a science map of the knowledge base on instructional leadership, 1940-2018
- Hallinger, Philip, Gümüş, Sedat, Bellibaş, Mehmet Şükrü
- Authors: Hallinger, Philip , Gümüş, Sedat , Bellibaş, Mehmet Şükrü
- Date: 2020
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/438702 , uj:38140 , Citation: Hallinger, P., Gümüş, S. & Bellibaş, M.S. 2020. 'Are principals instructional leaders yet?' a science map of the knowledge base on instructional leadership, 1940-2018.
- Description: Abstract: In the 1980s when research on effective schools surfaced the importance of 'instructional leadership in the United States, skeptics who wondered if this would be just another educational fad. Yet, 40 years later, the expectation for school principals to be 'instructional leaders' has become ubiquitous throughout much of the world. This systematic review of research used science mapping to gain insights into the growth, geographic distribution, key documents and authors, and topics in this literature. The authors used a variety of quantitative bibliometric analyses to examine 1,206 Scopus-indexed journal articles on instructional leadership published between 1940 and 2018. The results affirm that the knowledge base on instructional leadership has not only increased in size, but also geographic scope. Contrary to expectations during the 1980s, instructional leadership has demonstrated remarkable staying power, growing into one of the most powerful metaphors guiding research, policy and practice in school leadership. Despite this finding, both author co-citation and co-word analyses revealed the emergence of 'integrated models of school leadership' in which instructional leadership is enacted in concert with dimensions drawn from complementary leadership approaches. Key themes in the recent literature include studies of leadership effects on teachers and students, contexts for leadership practice, and means of developing instructional leaders.
- Full Text:
- Authors: Hallinger, Philip , Gümüş, Sedat , Bellibaş, Mehmet Şükrü
- Date: 2020
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/438702 , uj:38140 , Citation: Hallinger, P., Gümüş, S. & Bellibaş, M.S. 2020. 'Are principals instructional leaders yet?' a science map of the knowledge base on instructional leadership, 1940-2018.
- Description: Abstract: In the 1980s when research on effective schools surfaced the importance of 'instructional leadership in the United States, skeptics who wondered if this would be just another educational fad. Yet, 40 years later, the expectation for school principals to be 'instructional leaders' has become ubiquitous throughout much of the world. This systematic review of research used science mapping to gain insights into the growth, geographic distribution, key documents and authors, and topics in this literature. The authors used a variety of quantitative bibliometric analyses to examine 1,206 Scopus-indexed journal articles on instructional leadership published between 1940 and 2018. The results affirm that the knowledge base on instructional leadership has not only increased in size, but also geographic scope. Contrary to expectations during the 1980s, instructional leadership has demonstrated remarkable staying power, growing into one of the most powerful metaphors guiding research, policy and practice in school leadership. Despite this finding, both author co-citation and co-word analyses revealed the emergence of 'integrated models of school leadership' in which instructional leadership is enacted in concert with dimensions drawn from complementary leadership approaches. Key themes in the recent literature include studies of leadership effects on teachers and students, contexts for leadership practice, and means of developing instructional leaders.
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A case study of four South African War (1899-1902) Black concentration camps
- Authors: Benneyworth, Garth
- Date: 2020
- Subjects: Vereeniging , Meyerton , Witkop
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/462522 , uj:41245 , Citation: Benneyworth, G. 2020. A case study of four South African War (1899-1902) Black concentration camps.
- Description: Abstract: On 11 October 1899, the South African War commenced between the British Empire and the South African Republic and Orange Free State Republic. This conflict saw the targeting of civilians by all sides throughout the conflict and a harbinger of 20th century “Total War”, when civilians and their resources were harnessed to support military objectives. Set against the prior use of concentration camps in Cuba and the Philippines, the war was followed by a genocidal campaign undertaken by Imperial Germany against the Herero people in German South West Africa in 1906. Although civilian internment in South Africa was not genocidal by design and purpose, it caused a high loss of life and lasting bitterness amongst Boer descendants. Black concentration camps, however, were far more lethal to their internees and designed along a completely different model. Their role was to coerce labour while supporting the British war effort in defeating the Republican forces. Through a work or starve policy, combined with withholding food, medical support and shelter, many perished from systemic neglect. Yet the memory of this experience of the black concentration camps has entered historical discourse only recently, in the last three decades. The area of study, examined by this article, is those black concentration camps established during 1901 to 1902, at Klip River Station, Witkop, Meyerton and Vereeniging, in the former South African Republic (ZAR). Contemporary tangible evidence of these camps remains fleeting. However, this article identifies where these camps existed and how they were integrated into the British military’s counter-guerrilla warfare strategy. This in turn enables further research into these camps that may conclusively establish their historic locations.
- Full Text:
- Authors: Benneyworth, Garth
- Date: 2020
- Subjects: Vereeniging , Meyerton , Witkop
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/462522 , uj:41245 , Citation: Benneyworth, G. 2020. A case study of four South African War (1899-1902) Black concentration camps.
- Description: Abstract: On 11 October 1899, the South African War commenced between the British Empire and the South African Republic and Orange Free State Republic. This conflict saw the targeting of civilians by all sides throughout the conflict and a harbinger of 20th century “Total War”, when civilians and their resources were harnessed to support military objectives. Set against the prior use of concentration camps in Cuba and the Philippines, the war was followed by a genocidal campaign undertaken by Imperial Germany against the Herero people in German South West Africa in 1906. Although civilian internment in South Africa was not genocidal by design and purpose, it caused a high loss of life and lasting bitterness amongst Boer descendants. Black concentration camps, however, were far more lethal to their internees and designed along a completely different model. Their role was to coerce labour while supporting the British war effort in defeating the Republican forces. Through a work or starve policy, combined with withholding food, medical support and shelter, many perished from systemic neglect. Yet the memory of this experience of the black concentration camps has entered historical discourse only recently, in the last three decades. The area of study, examined by this article, is those black concentration camps established during 1901 to 1902, at Klip River Station, Witkop, Meyerton and Vereeniging, in the former South African Republic (ZAR). Contemporary tangible evidence of these camps remains fleeting. However, this article identifies where these camps existed and how they were integrated into the British military’s counter-guerrilla warfare strategy. This in turn enables further research into these camps that may conclusively establish their historic locations.
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A comparative analysis of Donald Bradman and Steven Smith: what are their secrets?
- Authors: Noorbhai, Habib
- Date: 2020
- Subjects: Biomechanics , Cricket , Performance
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/415459 , uj:35105 , Citation: Noorbhai H. A comparative analysis of Donald Bradman and Steven Smith: what are their secrets? BMJ Open Sport & Exercise Medicine 2020;6:e000720. doi:10.1136/ bmjsem-2019-000720
- Description: Abstract: , There has been growing evidence on the batting backlift technique in cricket at varying levels of cricket ability and the way in which batsmen direct or manoeuvre their bat in various ways. Most recently, there has been elevated awareness and discussion around the technique of Steven Smith. To an extent, there has been some comparison and reference been made to Sir Donald Bradman. Both Donald Bradman and Steven Smith have exhibited techniques and movements at the crease which many regard as ‘unorthodox’ or ‘unnatural’. This paper compares each of the batting technique components of both batsmen. The paper describes that both Bradman and Smith held their bat with an open grip which allowed them to hit the ball in most scoring areas of the field. The most common element that both batsmen demonstrate is a backlift that is directed towards the gulley or point region, otherwise known as the rotary method of batting, which is contrary to most of the coaching literature. Future research would require objective measures on Steven Smith to fully understand the kinetics and kinematics associated with his batting technique. The variances of performance averages across other formats (one-day internationals and 20-20 cricket) must be noted.
- Full Text:
- Authors: Noorbhai, Habib
- Date: 2020
- Subjects: Biomechanics , Cricket , Performance
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/415459 , uj:35105 , Citation: Noorbhai H. A comparative analysis of Donald Bradman and Steven Smith: what are their secrets? BMJ Open Sport & Exercise Medicine 2020;6:e000720. doi:10.1136/ bmjsem-2019-000720
- Description: Abstract: , There has been growing evidence on the batting backlift technique in cricket at varying levels of cricket ability and the way in which batsmen direct or manoeuvre their bat in various ways. Most recently, there has been elevated awareness and discussion around the technique of Steven Smith. To an extent, there has been some comparison and reference been made to Sir Donald Bradman. Both Donald Bradman and Steven Smith have exhibited techniques and movements at the crease which many regard as ‘unorthodox’ or ‘unnatural’. This paper compares each of the batting technique components of both batsmen. The paper describes that both Bradman and Smith held their bat with an open grip which allowed them to hit the ball in most scoring areas of the field. The most common element that both batsmen demonstrate is a backlift that is directed towards the gulley or point region, otherwise known as the rotary method of batting, which is contrary to most of the coaching literature. Future research would require objective measures on Steven Smith to fully understand the kinetics and kinematics associated with his batting technique. The variances of performance averages across other formats (one-day internationals and 20-20 cricket) must be noted.
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A comparative analysis of school physics curriculum content in selected countries
- Authors: Ramaila, S.
- Date: 2020
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/454043 , uj:40138 , Citation: Ramaila, S. 2020. A comparative analysis of school physics curriculum content in selected countries.
- Description: Abstract: Meaningful curriculum reform is central to the provision and acquisition of globally relevant scientific skills. A globally competitive curriculum fosters the cultivation of skills required for sustainable economic growth and development. In addition, it is imperative to harness the affordances associated with the provision of intellectually stimulating school physics curriculum content in order to foster the development of cognitive and reflective skills. In response to this key imperative, a comparative analysis of school physics curriculum content in selected countries was carried out with a view to identify levels of commonalities and the depth up to which each curriculum extends. Analysis of school physics curriculum content in selected countries revealed striking inherent characteristic features that serve to provide the structural differentiation between these curricula. The level of economic growth and development in selected countries appeared to be a function of the quality and depth of the school physics curriculum content. Theoretical implications for meaningful curriculum reform are discussed.
- Full Text:
- Authors: Ramaila, S.
- Date: 2020
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/454043 , uj:40138 , Citation: Ramaila, S. 2020. A comparative analysis of school physics curriculum content in selected countries.
- Description: Abstract: Meaningful curriculum reform is central to the provision and acquisition of globally relevant scientific skills. A globally competitive curriculum fosters the cultivation of skills required for sustainable economic growth and development. In addition, it is imperative to harness the affordances associated with the provision of intellectually stimulating school physics curriculum content in order to foster the development of cognitive and reflective skills. In response to this key imperative, a comparative analysis of school physics curriculum content in selected countries was carried out with a view to identify levels of commonalities and the depth up to which each curriculum extends. Analysis of school physics curriculum content in selected countries revealed striking inherent characteristic features that serve to provide the structural differentiation between these curricula. The level of economic growth and development in selected countries appeared to be a function of the quality and depth of the school physics curriculum content. Theoretical implications for meaningful curriculum reform are discussed.
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A comparative review on cold gas dynamic spraying processes and technologies
- Oyinbo, Sunday Temitope, Jen, Tien-Chien
- Authors: Oyinbo, Sunday Temitope , Jen, Tien-Chien
- Date: 2020
- Subjects: Cold gas dynamic spraying , Spraying parameters , Deformatiom mechanism
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/436831 , uj:37907 , Citation: Oyinbo, S.T. & Jen, T.C. 2020. A comparative review on cold gas dynamic spraying processes and technologies. , DOI: https://doi.org/10.1051/mfreview/2019023
- Description: Abstract: Cold gas dynamic spraying (CGDS) is a relatively new technology of cold spraying techniques that uses converging-diverging (De Laval) nozzle at a supersonic velocity to accelerate different solid powders towards a substrate where it plastically deforms on the substrate. This deformation results in adhesion to the surface. Several materials with viable deposition capability have been processed through cold spraying, including metals, ceramics, composite materials, and polymers, thereby creating a wide range of opportunities towards harnessing various properties. CGDS is one of the innovative cold spraying processes with fast-growing scientific interests and industrial applications in the field of aerospace, automotive and biotechnology, over the past years. Cold gas spraying with a wide range of materials offers corrosion protection and results in increases in mechanical durability and wear resistance. It creates components with different thermal and electrical conductivities than that substrates would yield, or produces coatings on the substrate components as thermal insulators and high fatigue-strength coatings, and for clearance control, restoration and repairing, or prostheses with improved wear, and produces components with attractive appearances. This review extensively exploits the latest developments in the experimental analysis of CGDS processes. Cold gas dynamic spraying system, coating formation and deposit development, description of process parameter and principles, are summarized. Industrial applications and prospectives of CGDS in future research are also commented.
- Full Text:
- Authors: Oyinbo, Sunday Temitope , Jen, Tien-Chien
- Date: 2020
- Subjects: Cold gas dynamic spraying , Spraying parameters , Deformatiom mechanism
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/436831 , uj:37907 , Citation: Oyinbo, S.T. & Jen, T.C. 2020. A comparative review on cold gas dynamic spraying processes and technologies. , DOI: https://doi.org/10.1051/mfreview/2019023
- Description: Abstract: Cold gas dynamic spraying (CGDS) is a relatively new technology of cold spraying techniques that uses converging-diverging (De Laval) nozzle at a supersonic velocity to accelerate different solid powders towards a substrate where it plastically deforms on the substrate. This deformation results in adhesion to the surface. Several materials with viable deposition capability have been processed through cold spraying, including metals, ceramics, composite materials, and polymers, thereby creating a wide range of opportunities towards harnessing various properties. CGDS is one of the innovative cold spraying processes with fast-growing scientific interests and industrial applications in the field of aerospace, automotive and biotechnology, over the past years. Cold gas spraying with a wide range of materials offers corrosion protection and results in increases in mechanical durability and wear resistance. It creates components with different thermal and electrical conductivities than that substrates would yield, or produces coatings on the substrate components as thermal insulators and high fatigue-strength coatings, and for clearance control, restoration and repairing, or prostheses with improved wear, and produces components with attractive appearances. This review extensively exploits the latest developments in the experimental analysis of CGDS processes. Cold gas dynamic spraying system, coating formation and deposit development, description of process parameter and principles, are summarized. Industrial applications and prospectives of CGDS in future research are also commented.
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A comparison of anterior and posterior central corneal powers in eyes with and without keratoconus
- Chetty, Elizabeth, Rubin, Alan
- Authors: Chetty, Elizabeth , Rubin, Alan
- Date: 2020
- Subjects: Keratoconus , Cornea , Multivariate analysis of dioptric power
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/460647 , uj:40999 , Citation: Chetty E, Rubin A. A comparison of anterior and posterior central corneal powers in eyes with and without keratoconus. Afr Vision Eye Health. 2020;79(1), a607. https:// , ISSN: (Online) 2410-1516
- Description: Abstract: Background: Keratoconus affects the anterior segment of the eye, which directly affects the refractive state of the eye. There are three components for the measurement of a corneal curvature or central corneal power (CCP) of the eye, namely, the power along the flat meridian, the power along the steep meridian and the axis of the flat meridian. Traditionally, CCP is analysed using univariate methods that processes each component separately; however, because of the trivariate nature of CCP, the use of multivariate methods and statistics may be beneficial. Aim: The aim of this study was to compare the short-term variation of the anterior and posterior CCP in eyes with and without keratoconus using multivariate methods of analysis. Setting: Data were extracted from a doctoral study by the first author. The group with keratoconus (KC) was obtained from patients attending a university-based contact lens clinic in Johannesburg, South Africa. Methods: A total of 28 eyes with KC and 28 eyes of 28 healthy control eyes without KC were included in this prospective quantitative study. Measurements were taken with the Oculus Pentacam (Wetzlar, Germany) and data related to the anterior and posterior CCP were analysed using multivariate methods and analysis. Results: For both KC and control groups, short-term variation of CCP of the anterior corneal surfaces was significantly greater than that for the posterior corneal surfaces. Whilst shortterm variation was similar for both corneal surfaces in the KC group, variation of the posterior corneal surfaces was significantly different from that of the anterior corneal surfaces for the control group. Conclusion: Multivariate analysis of short-term variation of CCP of both surfaces of the cornea in eyes with or without KC contributed towards a more complete understanding of the disease.
- Full Text:
- Authors: Chetty, Elizabeth , Rubin, Alan
- Date: 2020
- Subjects: Keratoconus , Cornea , Multivariate analysis of dioptric power
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/460647 , uj:40999 , Citation: Chetty E, Rubin A. A comparison of anterior and posterior central corneal powers in eyes with and without keratoconus. Afr Vision Eye Health. 2020;79(1), a607. https:// , ISSN: (Online) 2410-1516
- Description: Abstract: Background: Keratoconus affects the anterior segment of the eye, which directly affects the refractive state of the eye. There are three components for the measurement of a corneal curvature or central corneal power (CCP) of the eye, namely, the power along the flat meridian, the power along the steep meridian and the axis of the flat meridian. Traditionally, CCP is analysed using univariate methods that processes each component separately; however, because of the trivariate nature of CCP, the use of multivariate methods and statistics may be beneficial. Aim: The aim of this study was to compare the short-term variation of the anterior and posterior CCP in eyes with and without keratoconus using multivariate methods of analysis. Setting: Data were extracted from a doctoral study by the first author. The group with keratoconus (KC) was obtained from patients attending a university-based contact lens clinic in Johannesburg, South Africa. Methods: A total of 28 eyes with KC and 28 eyes of 28 healthy control eyes without KC were included in this prospective quantitative study. Measurements were taken with the Oculus Pentacam (Wetzlar, Germany) and data related to the anterior and posterior CCP were analysed using multivariate methods and analysis. Results: For both KC and control groups, short-term variation of CCP of the anterior corneal surfaces was significantly greater than that for the posterior corneal surfaces. Whilst shortterm variation was similar for both corneal surfaces in the KC group, variation of the posterior corneal surfaces was significantly different from that of the anterior corneal surfaces for the control group. Conclusion: Multivariate analysis of short-term variation of CCP of both surfaces of the cornea in eyes with or without KC contributed towards a more complete understanding of the disease.
- Full Text:
A critical interpretive synthesis of the roles of midwives in health systems
- Mattison, Cristina A., Lavis, John N., Wilson, Michael G., Hutton, Eileen K., Dion, Michelle L.
- Authors: Mattison, Cristina A. , Lavis, John N. , Wilson, Michael G. , Hutton, Eileen K. , Dion, Michelle L.
- Date: 2020
- Subjects: Midwifery , Political systems , Health systems
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/462563 , uj:41250 , Citation: Mattison, C.A. et al. 2020. A critical interpretive synthesis of the roles of midwives in health systems. , DOI: https://doi.org/10.1186/s12961-020-00590-0
- Description: Abstract: Please refer to full text to view abstract.
- Full Text:
- Authors: Mattison, Cristina A. , Lavis, John N. , Wilson, Michael G. , Hutton, Eileen K. , Dion, Michelle L.
- Date: 2020
- Subjects: Midwifery , Political systems , Health systems
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/462563 , uj:41250 , Citation: Mattison, C.A. et al. 2020. A critical interpretive synthesis of the roles of midwives in health systems. , DOI: https://doi.org/10.1186/s12961-020-00590-0
- Description: Abstract: Please refer to full text to view abstract.
- Full Text:
A cross-cultural investigation of young children’s spontaneous invention of tool use behaviours
- Neldner, Karri, Reindl, Eva, Tennie, Claudio, Grant, Julie, Tomaselli, Keyan, Nielsen, Mark
- Authors: Neldner, Karri , Reindl, Eva , Tennie, Claudio , Grant, Julie , Tomaselli, Keyan , Nielsen, Mark
- Date: 2020
- Subjects: Tool use , Problem solving , Physical cognition
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/432558 , uj:37368 , Citation: Neldner K, Reindl E, Tennie C, Grant J, Tomaselli K, Nielsen M. 2020 A crosscultural investigation of young children’s spontaneous invention of tool use behaviours. R. Soc. Open Sci. 7: 192240. http://dx.doi.org/10.1098/rsos.192240
- Description: Abstract: Through the mechanisms of observation, imitation and teaching, young children readily pick up the tool using behaviours of their culture. However, little is known about the baseline abilities of children’s tool use: what they might be capable of inventing on their own in the absence of socially provided information. It has been shown that children can spontaneously invent 11 of 12 candidate tool using behaviours observed within the foraging behaviours of wild non-human apes (Reindl et al. 2016 Proc. R. Soc. B 283, 20152402. (doi:10.1098/rspb.2015. 2402)). However, no investigations to date have examined how tool use invention in children might vary across cultural contexts. The current study investigated the levels of spontaneous tool use invention in 2- to 5-year-old children from San Bushmen communities in South Africa and children in a large city in Australia on the same 12 candidate problemsolving tasks. Children in both cultural contexts correctly invented all 12 candidate tool using behaviours, suggesting that these behaviours are within the general cognitive and physical capacities of human children and can be produced in the absence of direct social learning mechanisms such as teaching or observation.
- Full Text:
- Authors: Neldner, Karri , Reindl, Eva , Tennie, Claudio , Grant, Julie , Tomaselli, Keyan , Nielsen, Mark
- Date: 2020
- Subjects: Tool use , Problem solving , Physical cognition
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/432558 , uj:37368 , Citation: Neldner K, Reindl E, Tennie C, Grant J, Tomaselli K, Nielsen M. 2020 A crosscultural investigation of young children’s spontaneous invention of tool use behaviours. R. Soc. Open Sci. 7: 192240. http://dx.doi.org/10.1098/rsos.192240
- Description: Abstract: Through the mechanisms of observation, imitation and teaching, young children readily pick up the tool using behaviours of their culture. However, little is known about the baseline abilities of children’s tool use: what they might be capable of inventing on their own in the absence of socially provided information. It has been shown that children can spontaneously invent 11 of 12 candidate tool using behaviours observed within the foraging behaviours of wild non-human apes (Reindl et al. 2016 Proc. R. Soc. B 283, 20152402. (doi:10.1098/rspb.2015. 2402)). However, no investigations to date have examined how tool use invention in children might vary across cultural contexts. The current study investigated the levels of spontaneous tool use invention in 2- to 5-year-old children from San Bushmen communities in South Africa and children in a large city in Australia on the same 12 candidate problemsolving tasks. Children in both cultural contexts correctly invented all 12 candidate tool using behaviours, suggesting that these behaviours are within the general cognitive and physical capacities of human children and can be produced in the absence of direct social learning mechanisms such as teaching or observation.
- Full Text:
A cross-cultural investigation of young children’s spontaneous invention of tool use behaviours
- Nelder, Karri, Tennie, Claudio, Reindi, Eva, Grant, Julie, Tomaselli, Keyan, Nielsen, Mark
- Authors: Nelder, Karri , Tennie, Claudio , Reindi, Eva , Grant, Julie , Tomaselli, Keyan , Nielsen, Mark
- Date: 2020
- Subjects: Tool use , Problem sovling , Physical cognition
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/434105 , uj:37561 , Nelder, K. et al. 2020: A cross-cultural investigation of young children’s spontaneous invention of tool use behaviours
- Description: Abstract: , Through the mechanisms of observation, imitation and teaching, young children readily pick up the tool using behaviours of their culture. However, little is known about the baseline abilities of children's tool use: what they might be capable of inventing on their own in the absence of socially provided information. It has been shown that children can spontaneously invent 11 of 12 candidate tool using behaviours observed within the foraging behaviours of wild non-human apes (Reindl et al. 2016 Proc. R. Soc. B283, 20152402. (doi:10.1098/rspb.2015.2402)). However, no investigations to date have examined how tool use invention in children might vary across cultural contexts. The current study investigated the levels of spontaneous tool use invention in 2- to 5-year-old children from San Bushmen communities in South Africa and children in a large city in Australia on the same 12 candidate problem-solving tasks. Children in both cultural contexts correctly invented all 12 candidate tool using behaviours, suggesting that these behaviours are within the general cognitive and physical capacities of human children and can be produced in the absence of direct social learning mechanisms such as teaching or observation. Children in both cultures were more likely to invent those tool behaviours more frequently observed in great ape populations than those less frequently observed, suggesting there is similarity in the level of difficulty of invention across these behaviours for all great ape species. However, children in the Australian sample invented tool behaviours and succeeded on the tasks more often than did the Bushmen children, highlighting that aspects of a child's social or cultural environment may influence the rates of their tool use invention on such task sets, even when direct social information is absent.
- Full Text:
- Authors: Nelder, Karri , Tennie, Claudio , Reindi, Eva , Grant, Julie , Tomaselli, Keyan , Nielsen, Mark
- Date: 2020
- Subjects: Tool use , Problem sovling , Physical cognition
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/434105 , uj:37561 , Nelder, K. et al. 2020: A cross-cultural investigation of young children’s spontaneous invention of tool use behaviours
- Description: Abstract: , Through the mechanisms of observation, imitation and teaching, young children readily pick up the tool using behaviours of their culture. However, little is known about the baseline abilities of children's tool use: what they might be capable of inventing on their own in the absence of socially provided information. It has been shown that children can spontaneously invent 11 of 12 candidate tool using behaviours observed within the foraging behaviours of wild non-human apes (Reindl et al. 2016 Proc. R. Soc. B283, 20152402. (doi:10.1098/rspb.2015.2402)). However, no investigations to date have examined how tool use invention in children might vary across cultural contexts. The current study investigated the levels of spontaneous tool use invention in 2- to 5-year-old children from San Bushmen communities in South Africa and children in a large city in Australia on the same 12 candidate problem-solving tasks. Children in both cultural contexts correctly invented all 12 candidate tool using behaviours, suggesting that these behaviours are within the general cognitive and physical capacities of human children and can be produced in the absence of direct social learning mechanisms such as teaching or observation. Children in both cultures were more likely to invent those tool behaviours more frequently observed in great ape populations than those less frequently observed, suggesting there is similarity in the level of difficulty of invention across these behaviours for all great ape species. However, children in the Australian sample invented tool behaviours and succeeded on the tasks more often than did the Bushmen children, highlighting that aspects of a child's social or cultural environment may influence the rates of their tool use invention on such task sets, even when direct social information is absent.
- Full Text:
A cross-regional analysis of military expenditure, state fragility and economic growth in Africa
- Saba, Charles Shaaba, Ngepah, Nicholas
- Authors: Saba, Charles Shaaba , Ngepah, Nicholas
- Date: 2020
- Subjects: Military Expenditure , State Fragility , Economic Growth
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/453135 , uj:39994 , Citation: Saba, C.S. & Ngepah, N. 2020. A cross-regional analysis of military expenditure, state fragility and economic growth in Africa.
- Description: Abstract: This study investigates the relationship between military expenditure, state fragility and economic growth at regional economic communities of African countries. With a balanced panel of 34 African countries spanning 1990 to 2015. The variables of interest for this study include military expenditure, state fragility and economic growth. To measure economic growth, real gross domestic product per capita serves as the proxy, while state fragility is measured by the state fragility index, and military expenditure by military expenditure as a percentage share of GDP. We utilise: panel causality and cointegration test; and the Generalised Method of Moments (GMM) estimation techniques. The causality results suggest a feedback relationship among our variables of interest and this justified the use of GMM. Our analysis suggests that the effect of military expenditure on growth is negative at Africa level with significant regional economic level differences, and this effect is influenced in the presence of state fragility. This imply that there exist complementary effects between military expenditure and state fragility on growth. A cut in military expenditure and a consideration of other means of dealing with fragility issues as an alternative to joint regional militarised intervention of regional governments of African countries is recommended.
- Full Text:
- Authors: Saba, Charles Shaaba , Ngepah, Nicholas
- Date: 2020
- Subjects: Military Expenditure , State Fragility , Economic Growth
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/453135 , uj:39994 , Citation: Saba, C.S. & Ngepah, N. 2020. A cross-regional analysis of military expenditure, state fragility and economic growth in Africa.
- Description: Abstract: This study investigates the relationship between military expenditure, state fragility and economic growth at regional economic communities of African countries. With a balanced panel of 34 African countries spanning 1990 to 2015. The variables of interest for this study include military expenditure, state fragility and economic growth. To measure economic growth, real gross domestic product per capita serves as the proxy, while state fragility is measured by the state fragility index, and military expenditure by military expenditure as a percentage share of GDP. We utilise: panel causality and cointegration test; and the Generalised Method of Moments (GMM) estimation techniques. The causality results suggest a feedback relationship among our variables of interest and this justified the use of GMM. Our analysis suggests that the effect of military expenditure on growth is negative at Africa level with significant regional economic level differences, and this effect is influenced in the presence of state fragility. This imply that there exist complementary effects between military expenditure and state fragility on growth. A cut in military expenditure and a consideration of other means of dealing with fragility issues as an alternative to joint regional militarised intervention of regional governments of African countries is recommended.
- Full Text:
A Disease of Privilege? Social Representations in Online Conversations about Covid-19 amongst some South Africans during lockdown
- Sitto, Karabo, Lubinga, Elizabeth
- Authors: Sitto, Karabo , Lubinga, Elizabeth
- Date: 2020
- Subjects: Social representations , Socio-economic inequalities , South Africa
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/459643 , uj:40873 , Citation: Sitto, K. & Lubinga, E. 2020. A Disease of Privilege? Social Representations in Online Conversations about Covid-19 amongst some South Africans during lockdown.
- Description: Abstract: Responses by South Africans to communication from their government about the 2020 Covid-19 lockdown and proposed courses of action for containment have highlighted previously incommunicable socio-economic inequalities pervading access to healthcare. Government’s reaction in a bid to stem the Covid-19 global pandemic, though slow at commencement, has often been swift and decisive with regular briefings by ministerial clusters and the presidency in collaboration with various experts, displaying apparent transparency and ease of comprehension for audiences. However, there have arisen a range of oft-negative responses by citizens such announced courses of action, often based on representations of who the face of the virus is and in turn influencing their responses to government’s courses of action. A Social Representation approach was followed, with focus on citizen representations made regarding the spread of the Covid-19 virus, arising social representations and potential health communication consequences. The PEN-3 cultural model on health beliefs and actions presents a cultural yet contextual understanding of public health and health promotion by predicting people’s behaviour within their immediate environment. Social representations in reaction to initial news of the virus were those of a disease of those ‘lucky’ enough to be well-travelled and those privileged i.e. not the majority of South Africa, especially not black people...
- Full Text:
- Authors: Sitto, Karabo , Lubinga, Elizabeth
- Date: 2020
- Subjects: Social representations , Socio-economic inequalities , South Africa
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/459643 , uj:40873 , Citation: Sitto, K. & Lubinga, E. 2020. A Disease of Privilege? Social Representations in Online Conversations about Covid-19 amongst some South Africans during lockdown.
- Description: Abstract: Responses by South Africans to communication from their government about the 2020 Covid-19 lockdown and proposed courses of action for containment have highlighted previously incommunicable socio-economic inequalities pervading access to healthcare. Government’s reaction in a bid to stem the Covid-19 global pandemic, though slow at commencement, has often been swift and decisive with regular briefings by ministerial clusters and the presidency in collaboration with various experts, displaying apparent transparency and ease of comprehension for audiences. However, there have arisen a range of oft-negative responses by citizens such announced courses of action, often based on representations of who the face of the virus is and in turn influencing their responses to government’s courses of action. A Social Representation approach was followed, with focus on citizen representations made regarding the spread of the Covid-19 virus, arising social representations and potential health communication consequences. The PEN-3 cultural model on health beliefs and actions presents a cultural yet contextual understanding of public health and health promotion by predicting people’s behaviour within their immediate environment. Social representations in reaction to initial news of the virus were those of a disease of those ‘lucky’ enough to be well-travelled and those privileged i.e. not the majority of South Africa, especially not black people...
- Full Text:
A distributed real-time control algorithm for energy storage sharing
- Zhu, Hailing, Ouahada, Khmaies
- Authors: Zhu, Hailing , Ouahada, Khmaies
- Date: 2020
- Subjects: Energy management , Lyapunov optimization , Energy storage sharing
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/459635 , uj:40871 , Citation: Zhu, H. & Ouahada, K. 2020. A distributed real-time control algorithm for energy storage sharing.
- Description: Abstract: In this paper, energy storage sharing among a group of cooperative households with integrated renewable generations and controllable loads in a grid-connected microgrid is studied. In such a microgrid, a group of households, who cooperatively share an energy storage via a central coordinator, aims to minimize their long term time-averaged costs, by jointly taking into account the operational constraints of the shared energy storage, the stochastic solar energy generations, time-varying load requests and energy contribution to the shared energy storage from all households, as well as delay tolerance of their elastic loads. Exploiting delay tolerance of elastic loads, a joint storage management and load shifting system is present and a distributed online battery sharing control algorithm based on the Lyapunov theory is proposed. The proposed online control algorithm, which provides a suboptimal solution for the joint storage and load shifting problem based only on the current system state, coordinates the utilization of the shared battery among the households in a distributed manner, by jointly optimizing energy charging/discharging and load management for individual households while satisfying each household’s timevarying preference on energy use. Numerical simulation results show that, the proposed load shifting algorithm serves the load demands with a lower delay for each household at a similar average cost per kWh to that of a load shedding algorithm while facilitating a fairer utilization of the shared energy among households.
- Full Text:
- Authors: Zhu, Hailing , Ouahada, Khmaies
- Date: 2020
- Subjects: Energy management , Lyapunov optimization , Energy storage sharing
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/459635 , uj:40871 , Citation: Zhu, H. & Ouahada, K. 2020. A distributed real-time control algorithm for energy storage sharing.
- Description: Abstract: In this paper, energy storage sharing among a group of cooperative households with integrated renewable generations and controllable loads in a grid-connected microgrid is studied. In such a microgrid, a group of households, who cooperatively share an energy storage via a central coordinator, aims to minimize their long term time-averaged costs, by jointly taking into account the operational constraints of the shared energy storage, the stochastic solar energy generations, time-varying load requests and energy contribution to the shared energy storage from all households, as well as delay tolerance of their elastic loads. Exploiting delay tolerance of elastic loads, a joint storage management and load shifting system is present and a distributed online battery sharing control algorithm based on the Lyapunov theory is proposed. The proposed online control algorithm, which provides a suboptimal solution for the joint storage and load shifting problem based only on the current system state, coordinates the utilization of the shared battery among the households in a distributed manner, by jointly optimizing energy charging/discharging and load management for individual households while satisfying each household’s timevarying preference on energy use. Numerical simulation results show that, the proposed load shifting algorithm serves the load demands with a lower delay for each household at a similar average cost per kWh to that of a load shedding algorithm while facilitating a fairer utilization of the shared energy among households.
- Full Text:
A framework for digital transformation and business model innovation
- Van Tonder, C., Schachtebeck, C., Nieuwenhuizen, C., Bossink, B
- Authors: Van Tonder, C. , Schachtebeck, C. , Nieuwenhuizen, C. , Bossink, B
- Date: 2020
- Subjects: Digitalisation , Digital Transformation , Business Model Innovation
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/459699 , uj:40881 , Citation: Van Tonder, C. et al. 2020. A framework for digital transformation and business model innovation.
- Description: Abstract: With the advent of the Fourth Industrial Revolution, businesses are adapting to the use of digitalisation which requires the digital transformation of their existing business models. However, there is limited empirical research on this phenomenon. The purpose of this study is twofold: (i) to develop a framework for businesses to digitally transform their business models and (ii) to examine literature in order to identify and analyse the constructs underlying the three concepts of Digitalisation, Digital Transformation and Business Model Innovation. The study is qualitative in nature and is based on a narrative review. Relevant articles were identified in prominent international databases and scrutinised using thematic analysis. The findings reveal that the first two constructs require digital capabilities and a digital strategy. The third construct requires digital transformation in the realm of customer-centricity, resources, processes and profit...
- Full Text:
- Authors: Van Tonder, C. , Schachtebeck, C. , Nieuwenhuizen, C. , Bossink, B
- Date: 2020
- Subjects: Digitalisation , Digital Transformation , Business Model Innovation
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/459699 , uj:40881 , Citation: Van Tonder, C. et al. 2020. A framework for digital transformation and business model innovation.
- Description: Abstract: With the advent of the Fourth Industrial Revolution, businesses are adapting to the use of digitalisation which requires the digital transformation of their existing business models. However, there is limited empirical research on this phenomenon. The purpose of this study is twofold: (i) to develop a framework for businesses to digitally transform their business models and (ii) to examine literature in order to identify and analyse the constructs underlying the three concepts of Digitalisation, Digital Transformation and Business Model Innovation. The study is qualitative in nature and is based on a narrative review. Relevant articles were identified in prominent international databases and scrutinised using thematic analysis. The findings reveal that the first two constructs require digital capabilities and a digital strategy. The third construct requires digital transformation in the realm of customer-centricity, resources, processes and profit...
- Full Text:
A framework for explaining the role of values in health policy decision-making in Latin America : a critical interpretive synthesis
- Vélez, Marcela C., Wilson, Michael G., Lavis, John N., Abelson, Julia, Florez, Ivan D.
- Authors: Vélez, Marcela C. , Wilson, Michael G. , Lavis, John N. , Abelson, Julia , Florez, Ivan D.
- Date: 2020
- Subjects: Latin America , Critical interpretive synthesis , Values
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/462544 , uj:41248 , Citation: Vélez, M.C. et al. 2020. A framework for explaining the role of values in health policy decision-making in Latin America: a critical interpretive synthesis. , DOI: https://doi.org/10.1186/s12961-020-00584-y
- Description: Abstract: Background: Although values underpin the goals pursued in health systems, including how health systems benefit the population, it is often not clear how values are incorporated into policy decision-making about health systems. The challenge is to encompass social/citizen values, health system goals, and financial realities and to incorporate them into the policy-making process. This is a challenge for all health systems and of particular importance for Latin American (LA) countries. Our objective was to understand how and under what conditions societal values inform decisions about health system financing in LA countries. Methods: A critical interpretive synthesis approach was utilised for this work. We searched 17 databases in December 2016 to identify articles written in English, Spanish or Portuguese that focus on values that inform the policy process for health system financing in LA countries at the macro and meso levels. Two reviewers independently screened records and assessed them for inclusion. One researcher conceptually mapped the included articles, created structured summaries of key findings from each, and selected a purposive sample of articles to thematically synthesise the results across the domains of agenda-setting/prioritisation, policy development and implementation. Results: We identified 5925 references, included 199 papers, and synthesised 68 papers. We identified 116 values and developed a framework to explain how values have been used to inform policy decisions about financing in LA countries. This framework has four categories – (1) goal-related values (i.e. guiding principles of the health system); (2) technical values (those incorporated into the instruments adopted by policy-makers to ensure a sustainable and efficient health system); (3) governance values (those applied in the policy process to ensure a transparent and accountable process of decision-making); and (4) situational values (a broad category of values that represent competing strategies to make decisions in the health systems, their influence varying according to the four factors)...
- Full Text:
- Authors: Vélez, Marcela C. , Wilson, Michael G. , Lavis, John N. , Abelson, Julia , Florez, Ivan D.
- Date: 2020
- Subjects: Latin America , Critical interpretive synthesis , Values
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/462544 , uj:41248 , Citation: Vélez, M.C. et al. 2020. A framework for explaining the role of values in health policy decision-making in Latin America: a critical interpretive synthesis. , DOI: https://doi.org/10.1186/s12961-020-00584-y
- Description: Abstract: Background: Although values underpin the goals pursued in health systems, including how health systems benefit the population, it is often not clear how values are incorporated into policy decision-making about health systems. The challenge is to encompass social/citizen values, health system goals, and financial realities and to incorporate them into the policy-making process. This is a challenge for all health systems and of particular importance for Latin American (LA) countries. Our objective was to understand how and under what conditions societal values inform decisions about health system financing in LA countries. Methods: A critical interpretive synthesis approach was utilised for this work. We searched 17 databases in December 2016 to identify articles written in English, Spanish or Portuguese that focus on values that inform the policy process for health system financing in LA countries at the macro and meso levels. Two reviewers independently screened records and assessed them for inclusion. One researcher conceptually mapped the included articles, created structured summaries of key findings from each, and selected a purposive sample of articles to thematically synthesise the results across the domains of agenda-setting/prioritisation, policy development and implementation. Results: We identified 5925 references, included 199 papers, and synthesised 68 papers. We identified 116 values and developed a framework to explain how values have been used to inform policy decisions about financing in LA countries. This framework has four categories – (1) goal-related values (i.e. guiding principles of the health system); (2) technical values (those incorporated into the instruments adopted by policy-makers to ensure a sustainable and efficient health system); (3) governance values (those applied in the policy process to ensure a transparent and accountable process of decision-making); and (4) situational values (a broad category of values that represent competing strategies to make decisions in the health systems, their influence varying according to the four factors)...
- Full Text:
A genetic algorithm-based approach for three-phase fault evaluation in a distribution network
- Shambare, Chikomborero, Sun, Yanxia, Imoru, OdunAyo
- Authors: Shambare, Chikomborero , Sun, Yanxia , Imoru, OdunAyo
- Date: 2020
- Subjects: Autonomy , Evolutionary algorithms , Genetic Algorithm
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/453127 , uj:39993 , Citation: Shambare, C., Sun, Y & Imoru, O. 2020. A genetic algorithm-based approach for three-phase fault evaluation in a distribution network.
- Description: Abstract: Standard IEC 60909 provides all the basic information that is used in the evaluation of three-phase short circuit faults. However, it uses numerous estimations in its fault evaluation procedures. It estimates voltage factors, resistance to reactance ratios (R/X), resistance to impedance ratios (R/Z) and other scaling factors. These estimates do not cater for every nominal voltage. Users often have to approximate these values. In this paper, adjustments were made to the genetic algorithm (GA) with regards to gene replacements and arrangement of scores and expectation. During fault computation, the GA was used to stochastically determine R/X and R/Z ratios with regards to the parameters of the power system. The GA was tested on a nominal voltage that is properly catered for by Standard IEC. The GA results and the IEC values were within an approximate range. This implies that the developed GA can be further used to determine these ratios for nominal voltages that are not sufficiently accounted for by Standard IEC. This leads to obtaining precise fault values in all instances.
- Full Text:
- Authors: Shambare, Chikomborero , Sun, Yanxia , Imoru, OdunAyo
- Date: 2020
- Subjects: Autonomy , Evolutionary algorithms , Genetic Algorithm
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/453127 , uj:39993 , Citation: Shambare, C., Sun, Y & Imoru, O. 2020. A genetic algorithm-based approach for three-phase fault evaluation in a distribution network.
- Description: Abstract: Standard IEC 60909 provides all the basic information that is used in the evaluation of three-phase short circuit faults. However, it uses numerous estimations in its fault evaluation procedures. It estimates voltage factors, resistance to reactance ratios (R/X), resistance to impedance ratios (R/Z) and other scaling factors. These estimates do not cater for every nominal voltage. Users often have to approximate these values. In this paper, adjustments were made to the genetic algorithm (GA) with regards to gene replacements and arrangement of scores and expectation. During fault computation, the GA was used to stochastically determine R/X and R/Z ratios with regards to the parameters of the power system. The GA was tested on a nominal voltage that is properly catered for by Standard IEC. The GA results and the IEC values were within an approximate range. This implies that the developed GA can be further used to determine these ratios for nominal voltages that are not sufficiently accounted for by Standard IEC. This leads to obtaining precise fault values in all instances.
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