The cost of privatisation to the profession : media representation of audiology in Australia
- Šarkić, Bojana, Simpson, Andrea, Heine, Chrysse
- Authors: Šarkić, Bojana , Simpson, Andrea , Heine, Chrysse
- Date: 2023
- Type: Text , Journal article , Review
- Relation: Health Promotion Journal of Australia Vol. 34, no. 2 (2023), p. 603-611
- Full Text:
- Reviewed:
- Description: Purpose: To investigate how the profession of audiology was represented in the media in Australia and how the increased privatisation of the profession may have shaped this representation. Methods: A systematic search of English language media records was conducted from 1 January 2000 to 17 July 2020 using ANZ News Stream, TV News, Google News and INFORMIT. Twenty-four of 1056 originally identified articles were retained. The findings were extracted and synthesised. Results: Context and content analyses were preformed, revealing a predominantly negative portrayal of Audiology as a profession in 21 (87.5%) of 24 articles. Predominant themes included: sales driven by incentives; predatory strategies and malpractice; non-regulation and privatisation of the hearing care industry; and conflict of interest. Conclusions: The media was found to highlight consumer mistrust in the profession in recent years. Increased regulation of the profession of audiology is recommended to protect the population against exploitative practices and to renew faith in the profession by the public. © 2022 The Authors. Health Promotion Journal of Australia published by John Wiley & Sons Australia, Ltd on behalf of Australian Health Promotion Association.
- Authors: Šarkić, Bojana , Simpson, Andrea , Heine, Chrysse
- Date: 2023
- Type: Text , Journal article , Review
- Relation: Health Promotion Journal of Australia Vol. 34, no. 2 (2023), p. 603-611
- Full Text:
- Reviewed:
- Description: Purpose: To investigate how the profession of audiology was represented in the media in Australia and how the increased privatisation of the profession may have shaped this representation. Methods: A systematic search of English language media records was conducted from 1 January 2000 to 17 July 2020 using ANZ News Stream, TV News, Google News and INFORMIT. Twenty-four of 1056 originally identified articles were retained. The findings were extracted and synthesised. Results: Context and content analyses were preformed, revealing a predominantly negative portrayal of Audiology as a profession in 21 (87.5%) of 24 articles. Predominant themes included: sales driven by incentives; predatory strategies and malpractice; non-regulation and privatisation of the hearing care industry; and conflict of interest. Conclusions: The media was found to highlight consumer mistrust in the profession in recent years. Increased regulation of the profession of audiology is recommended to protect the population against exploitative practices and to renew faith in the profession by the public. © 2022 The Authors. Health Promotion Journal of Australia published by John Wiley & Sons Australia, Ltd on behalf of Australian Health Promotion Association.
Mosquito surveillance of West Nile and Usutu viruses in four territorial units of Slovakia and description of a confirmed autochthonous human case of West Nile fever, 2018 to 2019
- Čabanová, Viktória, Tichá, Elena, Bradbury, Richard, Zubriková, Dana, Valentová, Daniela, Chovancová, Gabriela, Grešáková,, Víchová, Bronislava, Šikutová, Silvie, Csank, Tomas, Hurníková, Zuzana, Miterpáková, Martina, Rudolf, Ivo
- Authors: Čabanová, Viktória , Tichá, Elena , Bradbury, Richard , Zubriková, Dana , Valentová, Daniela , Chovancová, Gabriela , Grešáková, , Víchová, Bronislava , Šikutová, Silvie , Csank, Tomas , Hurníková, Zuzana , Miterpáková, Martina , Rudolf, Ivo
- Date: 2021
- Type: Text , Journal article
- Relation: Eurosurveillance Vol. 26, no. 19 (2021), p.
- Full Text:
- Reviewed:
- Description: Background: Despite the known circulation of West Nile virus (WNV) and Usutu virus (USUV) in Slovakia, no formal entomological surveillance programme has been established there thus far. Aim: To conduct contemporaneous surveillance of WNV and USUV in different areas of Slovakia and to assess the geographical spread of these viruses through mosquito vectors. The first autochthonous human WNV infection in the country is also described. Methods: Mosquitoes were trapped in four Slovak territorial units in 2018 and 2019. Species were characterised morphologically and mosquito pools screened for WNV and USUV by real-time reverse-transcription PCRs. In pools with any of the two viruses detected, presence of pipiens complex group mosquitoes was verified using molecular approaches. Results: Altogether, 421 pools containing in total 4,508 mosquitoes were screened. Three pools tested positive for WNV and 16 for USUV. USUV was more prevalent than WNV, with a broader spectrum of vectors and was detected over a longer period (June-October vs August for WNV). The main vectors of both viruses were Culex pipiens sensu lato. Importantly, WNV and USUV were identified in a highly urbanised area of Bratislava city, Slovakias' capital city. Moreover, in early September 2019, a patient, who had been bitten by mosquitoes in southwestern Slovakia and who had not travelled abroad, was laboratory-confirmed with WNV infection. Conclusion: The entomological survey results and case report increase current understanding of the WNV and USUV situation in Slovakia. They underline the importance of vector surveillance to assess public health risks posed by these viruses. © 2021 European Centre for Disease Prevention and Control (ECDC). All rights reserved.
- Authors: Čabanová, Viktória , Tichá, Elena , Bradbury, Richard , Zubriková, Dana , Valentová, Daniela , Chovancová, Gabriela , Grešáková, , Víchová, Bronislava , Šikutová, Silvie , Csank, Tomas , Hurníková, Zuzana , Miterpáková, Martina , Rudolf, Ivo
- Date: 2021
- Type: Text , Journal article
- Relation: Eurosurveillance Vol. 26, no. 19 (2021), p.
- Full Text:
- Reviewed:
- Description: Background: Despite the known circulation of West Nile virus (WNV) and Usutu virus (USUV) in Slovakia, no formal entomological surveillance programme has been established there thus far. Aim: To conduct contemporaneous surveillance of WNV and USUV in different areas of Slovakia and to assess the geographical spread of these viruses through mosquito vectors. The first autochthonous human WNV infection in the country is also described. Methods: Mosquitoes were trapped in four Slovak territorial units in 2018 and 2019. Species were characterised morphologically and mosquito pools screened for WNV and USUV by real-time reverse-transcription PCRs. In pools with any of the two viruses detected, presence of pipiens complex group mosquitoes was verified using molecular approaches. Results: Altogether, 421 pools containing in total 4,508 mosquitoes were screened. Three pools tested positive for WNV and 16 for USUV. USUV was more prevalent than WNV, with a broader spectrum of vectors and was detected over a longer period (June-October vs August for WNV). The main vectors of both viruses were Culex pipiens sensu lato. Importantly, WNV and USUV were identified in a highly urbanised area of Bratislava city, Slovakias' capital city. Moreover, in early September 2019, a patient, who had been bitten by mosquitoes in southwestern Slovakia and who had not travelled abroad, was laboratory-confirmed with WNV infection. Conclusion: The entomological survey results and case report increase current understanding of the WNV and USUV situation in Slovakia. They underline the importance of vector surveillance to assess public health risks posed by these viruses. © 2021 European Centre for Disease Prevention and Control (ECDC). All rights reserved.
Carfilzomib promotes the unfolded protein response and apoptosis in cetuximab-resistant colorectal cancer
- Zulkifli, Ahmad, Tan, Fiona, Areeb, Zammam, Stuart, Sarah, Luwor, Rodney
- Authors: Zulkifli, Ahmad , Tan, Fiona , Areeb, Zammam , Stuart, Sarah , Luwor, Rodney
- Date: 2021
- Type: Text , Journal article
- Relation: International Journal of Molecular Sciences Vol. 22, no. 13 (2021), p.
- Full Text:
- Reviewed:
- Description: Cetuximab is a common treatment option for patients with wild-type K-Ras colorectal carcinoma. However, patients often display intrinsic resistance or acquire resistance to cetuximab following treatment. Here we generate two human CRC cells with acquired resistance to cetuximab that are derived from cetuximab-sensitive parental cell lines. These cetuximab-resistant cells display greater in vitro proliferation, colony formation and migration, and in vivo tumour growth compared with their parental counterparts. To evaluate potential alternative therapeutics to cetuximab-acquired-resistant cells, we tested the efficacy of 38 current FDA-approved agents against our cetuximab-acquired-resistant clones. We identified carfilzomib, a selective proteosome inhibitor to be most effective against our cell lines. Carfilzomib displayed potent antiproliferative effects, induced the unfolded protein response as determined by enhanced CHOP expression and ATF6 activity, and enhanced apoptosis as determined by enhanced caspase-3/7 activity. Overall, our results indicate a potentially novel indication for carfilzomib: that of a potential alternative agent to treat cetuximab-resistant colorectal cancer. © 2021 by the authors. Licensee MDPI, Basel, Switzerland. **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Rodney Luwor” is provided in this record**
- Authors: Zulkifli, Ahmad , Tan, Fiona , Areeb, Zammam , Stuart, Sarah , Luwor, Rodney
- Date: 2021
- Type: Text , Journal article
- Relation: International Journal of Molecular Sciences Vol. 22, no. 13 (2021), p.
- Full Text:
- Reviewed:
- Description: Cetuximab is a common treatment option for patients with wild-type K-Ras colorectal carcinoma. However, patients often display intrinsic resistance or acquire resistance to cetuximab following treatment. Here we generate two human CRC cells with acquired resistance to cetuximab that are derived from cetuximab-sensitive parental cell lines. These cetuximab-resistant cells display greater in vitro proliferation, colony formation and migration, and in vivo tumour growth compared with their parental counterparts. To evaluate potential alternative therapeutics to cetuximab-acquired-resistant cells, we tested the efficacy of 38 current FDA-approved agents against our cetuximab-acquired-resistant clones. We identified carfilzomib, a selective proteosome inhibitor to be most effective against our cell lines. Carfilzomib displayed potent antiproliferative effects, induced the unfolded protein response as determined by enhanced CHOP expression and ATF6 activity, and enhanced apoptosis as determined by enhanced caspase-3/7 activity. Overall, our results indicate a potentially novel indication for carfilzomib: that of a potential alternative agent to treat cetuximab-resistant colorectal cancer. © 2021 by the authors. Licensee MDPI, Basel, Switzerland. **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Rodney Luwor” is provided in this record**
To be fair or efficient or a bit of both
- Zukerman, Moshe, Mammadov, Musa, Tan, Liansheng, Ouveysi, Iradj, Andrew, Lachlan
- Authors: Zukerman, Moshe , Mammadov, Musa , Tan, Liansheng , Ouveysi, Iradj , Andrew, Lachlan
- Date: 2008
- Type: Text , Journal article
- Relation: Computers and Operations Research Vol. 35, no. 12 (2008), p. 3787-3806
- Full Text:
- Reviewed:
- Description: IIntroducing a new concept of (®, ¯)-fairness, which allows for a bounded fairness compromise, so that a source is allocated a rate neither less than 0 · ® · 1, nor more than ¯ ¸ 1, times its fair share, this paper provides a framework to optimize efficiency (utilization, throughput or revenue) subject to fairness constraints in a general telecommunications network for an arbitrary fairness criterion and cost functions. We formulate a non-linear program (NLP) that finds the optimal bandwidth allocation by maximizing efficiency subject to (®, ¯)-fairness constraints. This leads to what we call an efficiency-fairness function, which shows the benefit in efficiency as a function of the extent to which fairness is compromised. To solve the NLP we use two algorithms. The first is a well known branch-and-bound-based algorithm called Lipschitz Global Optimization and the second is a recently developed algorithm called Algorithm for Global Optimization Problems (AGOP). We demonstrate the applicability of the framework to a range of example from sharing a single link to efficiency fairness issues associated with serving customers in remote communities.
- Description: C1
- Authors: Zukerman, Moshe , Mammadov, Musa , Tan, Liansheng , Ouveysi, Iradj , Andrew, Lachlan
- Date: 2008
- Type: Text , Journal article
- Relation: Computers and Operations Research Vol. 35, no. 12 (2008), p. 3787-3806
- Full Text:
- Reviewed:
- Description: IIntroducing a new concept of (®, ¯)-fairness, which allows for a bounded fairness compromise, so that a source is allocated a rate neither less than 0 · ® · 1, nor more than ¯ ¸ 1, times its fair share, this paper provides a framework to optimize efficiency (utilization, throughput or revenue) subject to fairness constraints in a general telecommunications network for an arbitrary fairness criterion and cost functions. We formulate a non-linear program (NLP) that finds the optimal bandwidth allocation by maximizing efficiency subject to (®, ¯)-fairness constraints. This leads to what we call an efficiency-fairness function, which shows the benefit in efficiency as a function of the extent to which fairness is compromised. To solve the NLP we use two algorithms. The first is a well known branch-and-bound-based algorithm called Lipschitz Global Optimization and the second is a recently developed algorithm called Algorithm for Global Optimization Problems (AGOP). We demonstrate the applicability of the framework to a range of example from sharing a single link to efficiency fairness issues associated with serving customers in remote communities.
- Description: C1
Space : Contemplating the voids
- Authors: Zuccolo, Michelle
- Date: 2006
- Type: Text , Thesis , Masters
- Full Text:
- Description: This research project into the manipulation of spatial concepts by artists on the two-dimensional surface plane, has involved a selected study into cultural and aesthetic evolution from early civilization through to the present era. I have cast a line of inquiry into eastern, western and primitive art practices, observing the journey of chance accelerated by developments in technology. Traditionally artists utilized modes of spatial convention and techniques according to the specific cultural traditions of the time and place of their production. By contrast, contemporary artists know no such boundaries, and are able to select from a range of spatial options relevant both to current forms of expression and to a personal visual language. My own art practice has been enriched and extended, increasing my ability to challenge the notion of still life composition by reversing the traditional hierarchy of form and space through the application of a series of experiments brought about by extensive research into this spatial evolution. The research project has further assisted this development in my art practice by engaging me in a new level of understanding of the topic, informing my perceptions and increasing my ability to translate a combination of forms in space with heightened emotion and personal meaning.
- Description: Master of Arts (Visual Arts)
- Authors: Zuccolo, Michelle
- Date: 2006
- Type: Text , Thesis , Masters
- Full Text:
- Description: This research project into the manipulation of spatial concepts by artists on the two-dimensional surface plane, has involved a selected study into cultural and aesthetic evolution from early civilization through to the present era. I have cast a line of inquiry into eastern, western and primitive art practices, observing the journey of chance accelerated by developments in technology. Traditionally artists utilized modes of spatial convention and techniques according to the specific cultural traditions of the time and place of their production. By contrast, contemporary artists know no such boundaries, and are able to select from a range of spatial options relevant both to current forms of expression and to a personal visual language. My own art practice has been enriched and extended, increasing my ability to challenge the notion of still life composition by reversing the traditional hierarchy of form and space through the application of a series of experiments brought about by extensive research into this spatial evolution. The research project has further assisted this development in my art practice by engaging me in a new level of understanding of the topic, informing my perceptions and increasing my ability to translate a combination of forms in space with heightened emotion and personal meaning.
- Description: Master of Arts (Visual Arts)
The expendable teacher in covid-19 times : a poetic inquiry into the reconfiguration of governmentality in victorian schools
- Zonca, Benjamin, Ambrosy, Josh
- Authors: Zonca, Benjamin , Ambrosy, Josh
- Date: 2021
- Type: Text , Journal article
- Relation: Journal for Critical Education Policy Studies Vol. 19, no. 1 (2021), p. 212-248
- Full Text:
- Reviewed:
- Description: The actualization of a neoliberal rationality has been widely explored in global education policy and Australian schools. This paper draws on engagements with neoliberalism as rationality made ‘real’ through government practices, specifically those that reify the teaching profession into one of risk-management and problem-solving at the expense of deliberation about purposes. In this paper, redacted policy poetry and participant-voiced poetry are employed in parallel to explore the COVID-19 crisis as it emerged in the State of Victoria, Australia with a specific focus on the reconfiguration of risk-management discourses through blanket policy directive. This paper identifies and explores three themes highlighted by this reconfiguration of risk discourse and shifts in modes of governance during this time that are magnified by a teacher’s affective and practical responses to the situation. They are: (1) collective teacher response to overt policy decisions that compel the teacher to embrace risk; (2) contradictions of expectation for schools to continue as usual; and (3) an explicit shift away from instrumental evidence-based pedagogies toward new purposes, pedagogies, and community engagement with little guidance. © 2021, Institute for Education Policy Studies. All rights reserved.
- Authors: Zonca, Benjamin , Ambrosy, Josh
- Date: 2021
- Type: Text , Journal article
- Relation: Journal for Critical Education Policy Studies Vol. 19, no. 1 (2021), p. 212-248
- Full Text:
- Reviewed:
- Description: The actualization of a neoliberal rationality has been widely explored in global education policy and Australian schools. This paper draws on engagements with neoliberalism as rationality made ‘real’ through government practices, specifically those that reify the teaching profession into one of risk-management and problem-solving at the expense of deliberation about purposes. In this paper, redacted policy poetry and participant-voiced poetry are employed in parallel to explore the COVID-19 crisis as it emerged in the State of Victoria, Australia with a specific focus on the reconfiguration of risk-management discourses through blanket policy directive. This paper identifies and explores three themes highlighted by this reconfiguration of risk discourse and shifts in modes of governance during this time that are magnified by a teacher’s affective and practical responses to the situation. They are: (1) collective teacher response to overt policy decisions that compel the teacher to embrace risk; (2) contradictions of expectation for schools to continue as usual; and (3) an explicit shift away from instrumental evidence-based pedagogies toward new purposes, pedagogies, and community engagement with little guidance. © 2021, Institute for Education Policy Studies. All rights reserved.
A step toward restoring hand functions in patients with multiple sclerosis—a study protocol
- Zoghi, Maryam, Jaberzadeh, Shapour
- Authors: Zoghi, Maryam , Jaberzadeh, Shapour
- Date: 2023
- Type: Text , Journal article
- Relation: Frontiers in Rehabilitation Sciences Vol. 4, no. (2023), p.
- Full Text:
- Reviewed:
- Description: Multiple sclerosis (MS) is a chronic autoimmune disease characterized by inflammation, demyelination of axons, and oligodendrocyte loss in the central nervous system. This leads to neurological dysfunction, including hand impairment, which is prevalent among patients with MS. However, hand impairment is the least targeted area for neurorehabilitation studies. Therefore, this study proposes a novel approach to improve hand functions compared to current strategies. Studies have shown that learning new skills in the motor cortex (M1) can trigger the production of oligodendrocytes and myelin, which is a critical mechanism for neuroplasticity. Transcranial direct current stimulation (tDCS) has been used to enhance motor learning and function in human subjects. However, tDCS induces non-specific effects, and concurrent behavioral training has been found to optimize its benefits. Recent research indicates that applying tDCS during motor learning can have priming effects on the long-term potentiation mechanism and prolong the effects of motor training in health and disease. Therefore, this study aims to assess whether applying repeated tDCS during the learning of a new motor skill in M1 can be more effective in improving hand functions in patients with MS than current neurorehabilitation strategies. If this approach proves successful in improving hand functions in patients with MS, it could be adopted as a new approach to restore hand functions. Additionally, if the application of tDCS demonstrates an accumulative effect in improving hand functions in patients with MS, it could provide an adjunct intervention during rehabilitation for these patients. This study will contribute to the growing body of literature on the use of tDCS in neurorehabilitation and could have a significant impact on the quality of life of patients with MS. 2023 Zoghi and Jaberzadeh.
- Authors: Zoghi, Maryam , Jaberzadeh, Shapour
- Date: 2023
- Type: Text , Journal article
- Relation: Frontiers in Rehabilitation Sciences Vol. 4, no. (2023), p.
- Full Text:
- Reviewed:
- Description: Multiple sclerosis (MS) is a chronic autoimmune disease characterized by inflammation, demyelination of axons, and oligodendrocyte loss in the central nervous system. This leads to neurological dysfunction, including hand impairment, which is prevalent among patients with MS. However, hand impairment is the least targeted area for neurorehabilitation studies. Therefore, this study proposes a novel approach to improve hand functions compared to current strategies. Studies have shown that learning new skills in the motor cortex (M1) can trigger the production of oligodendrocytes and myelin, which is a critical mechanism for neuroplasticity. Transcranial direct current stimulation (tDCS) has been used to enhance motor learning and function in human subjects. However, tDCS induces non-specific effects, and concurrent behavioral training has been found to optimize its benefits. Recent research indicates that applying tDCS during motor learning can have priming effects on the long-term potentiation mechanism and prolong the effects of motor training in health and disease. Therefore, this study aims to assess whether applying repeated tDCS during the learning of a new motor skill in M1 can be more effective in improving hand functions in patients with MS than current neurorehabilitation strategies. If this approach proves successful in improving hand functions in patients with MS, it could be adopted as a new approach to restore hand functions. Additionally, if the application of tDCS demonstrates an accumulative effect in improving hand functions in patients with MS, it could provide an adjunct intervention during rehabilitation for these patients. This study will contribute to the growing body of literature on the use of tDCS in neurorehabilitation and could have a significant impact on the quality of life of patients with MS. 2023 Zoghi and Jaberzadeh.
Teacher perceptions of changes in school infrastructure and how these impact on their teaching practice
- Authors: Zivave, Takavada
- Date: 2021
- Type: Text , Thesis , PhD
- Full Text:
- Description: The impetus of this study comes from the 2009 Commonwealth Government of Australia’s $16.2 billion investment in school infrastructure under the Building the Education Revolution (BER) program. The BER program was supposed to stimulate the economy through creating construction jobs by building schools and ensuring that workers had jobs during the global financial crisis. Provision of learning spaces and learning space design was secondary to this need to create construction jobs. This thesis aimed to explore the teaching activity using an activity system based on Cultural-Historical Activity Theory (CHAT) (Engestrom, 1987) with the intent of bringing out or exposing the contribution made by the BER school infrastructure program on teaching especially around issues of pedagogy, teamwork, wellbeing, collaboration and interactions with students. Using a mixed-methods approach, the study utilised three sources of data, document analysis, online survey responses and focus group interviews. In the first phase, data were collected using a document analysis, this information guided the design of the online survey instrument, which was used to collect data in the second phase. Data collected using both the document analysis and online survey responses were used in the third phase, which involved focus group interviews. The data analysis involved identifying, grouping together and labelling document analysis, data from the online survey and transcripts of focus group interviews. These were coded and organised into themes, or units of meaning. The quantitative data was presented in frequency tables and descriptive statistics. This quantitative data was corroborated with extracts from focus group interviews and document analysis data where possible. The study’s findings demonstrated that school infrastructure supports teacher collaboration by allowing for team planning and co-teaching. Furthermore, the study revealed a link between teacher collaboration and teacher wellbeing. The study findings indicate that when teachers plan together and co-teach, their workload is reduced contributing positively to teacher wellbeing. The study suggests that a relationship exists between school infrastructure and student-teacher interactions, which serves to reduce negative interactions when dealing with outside classroom behaviour. The present study seeks to generate insights that, while unique to participants and individuals, are anticipated to be of interest to teachers more broadly. Potentially, the findings from this study could inform other educational contexts, for example, school architectural designers. Significantly, this research seeks to contribute to literature on the importance of school infrastructure on teacher performance ultimately improving student-learning outcomes.
- Description: Doctor of Philosophy
- Authors: Zivave, Takavada
- Date: 2021
- Type: Text , Thesis , PhD
- Full Text:
- Description: The impetus of this study comes from the 2009 Commonwealth Government of Australia’s $16.2 billion investment in school infrastructure under the Building the Education Revolution (BER) program. The BER program was supposed to stimulate the economy through creating construction jobs by building schools and ensuring that workers had jobs during the global financial crisis. Provision of learning spaces and learning space design was secondary to this need to create construction jobs. This thesis aimed to explore the teaching activity using an activity system based on Cultural-Historical Activity Theory (CHAT) (Engestrom, 1987) with the intent of bringing out or exposing the contribution made by the BER school infrastructure program on teaching especially around issues of pedagogy, teamwork, wellbeing, collaboration and interactions with students. Using a mixed-methods approach, the study utilised three sources of data, document analysis, online survey responses and focus group interviews. In the first phase, data were collected using a document analysis, this information guided the design of the online survey instrument, which was used to collect data in the second phase. Data collected using both the document analysis and online survey responses were used in the third phase, which involved focus group interviews. The data analysis involved identifying, grouping together and labelling document analysis, data from the online survey and transcripts of focus group interviews. These were coded and organised into themes, or units of meaning. The quantitative data was presented in frequency tables and descriptive statistics. This quantitative data was corroborated with extracts from focus group interviews and document analysis data where possible. The study’s findings demonstrated that school infrastructure supports teacher collaboration by allowing for team planning and co-teaching. Furthermore, the study revealed a link between teacher collaboration and teacher wellbeing. The study findings indicate that when teachers plan together and co-teach, their workload is reduced contributing positively to teacher wellbeing. The study suggests that a relationship exists between school infrastructure and student-teacher interactions, which serves to reduce negative interactions when dealing with outside classroom behaviour. The present study seeks to generate insights that, while unique to participants and individuals, are anticipated to be of interest to teachers more broadly. Potentially, the findings from this study could inform other educational contexts, for example, school architectural designers. Significantly, this research seeks to contribute to literature on the importance of school infrastructure on teacher performance ultimately improving student-learning outcomes.
- Description: Doctor of Philosophy
Accounting for cryptic population substructure enhances detection of inbreeding depression with genomic inbreeding coefficients: an example from a critically endangered marsupial
- Zilko, Joseph, Harley, Dan, Hansen, Birgita, Pavlova, Alexandra, Sunnucks, Paul
- Authors: Zilko, Joseph , Harley, Dan , Hansen, Birgita , Pavlova, Alexandra , Sunnucks, Paul
- Date: 2020
- Type: Text , Journal article
- Relation: Molecular Ecology Vol. 29, no. 16 (2020), p. 2978-2993
- Full Text:
- Reviewed:
- Description: Characterizing inbreeding depression in wildlife populations can be critical to their conservation. Coefficients of individual inbreeding can be estimated from genome-wide marker data. The degree to which sensitivity of inbreeding coefficients to population genetic substructure alters estimates of inbreeding depression in wild populations is not well understood. Using generalized linear models, we tested the power of two frequently used inbreeding coefficients that are calculated from genome-wide SNP markers, FH and F^III, to predict four fitness traits estimated over two decades in an isolated population of the critically endangered Leadbeater's possum. FH estimates inbreeding as excess observed homozygotes relative to equilibrium expectations, whereas F^III quantifies allelic similarity between the gametes that formed an individual, and upweights rare homozygotes. We estimated FH and F^III from 1,575 genome-wide SNP loci in individuals with fitness trait data (N = 179–237 per trait), and computed revised coefficients, FHby group and F^IIIby group, adjusted for population genetic substructure by calculating them separately within two different genetic groups of individuals identified in the population. Using FH or F^III in the models, inbreeding depression was detected for survival to sexual maturity, longevity and whether individuals bred during their lifetime. F^IIIby group (but not FHby group) additionally revealed significant inbreeding depression for lifetime reproductive output (total offspring assigned to each individual). Estimates of numbers of lethal equivalents indicated substantial inbreeding load, but differing between inbreeding estimators. Inbreeding depression, declining population size, and low and declining genetic diversity suggest that genetic rescue may assist in preventing extinction of this unique Leadbeater's possum population. © 2020 John Wiley & Sons Ltd
- Authors: Zilko, Joseph , Harley, Dan , Hansen, Birgita , Pavlova, Alexandra , Sunnucks, Paul
- Date: 2020
- Type: Text , Journal article
- Relation: Molecular Ecology Vol. 29, no. 16 (2020), p. 2978-2993
- Full Text:
- Reviewed:
- Description: Characterizing inbreeding depression in wildlife populations can be critical to their conservation. Coefficients of individual inbreeding can be estimated from genome-wide marker data. The degree to which sensitivity of inbreeding coefficients to population genetic substructure alters estimates of inbreeding depression in wild populations is not well understood. Using generalized linear models, we tested the power of two frequently used inbreeding coefficients that are calculated from genome-wide SNP markers, FH and F^III, to predict four fitness traits estimated over two decades in an isolated population of the critically endangered Leadbeater's possum. FH estimates inbreeding as excess observed homozygotes relative to equilibrium expectations, whereas F^III quantifies allelic similarity between the gametes that formed an individual, and upweights rare homozygotes. We estimated FH and F^III from 1,575 genome-wide SNP loci in individuals with fitness trait data (N = 179–237 per trait), and computed revised coefficients, FHby group and F^IIIby group, adjusted for population genetic substructure by calculating them separately within two different genetic groups of individuals identified in the population. Using FH or F^III in the models, inbreeding depression was detected for survival to sexual maturity, longevity and whether individuals bred during their lifetime. F^IIIby group (but not FHby group) additionally revealed significant inbreeding depression for lifetime reproductive output (total offspring assigned to each individual). Estimates of numbers of lethal equivalents indicated substantial inbreeding load, but differing between inbreeding estimators. Inbreeding depression, declining population size, and low and declining genetic diversity suggest that genetic rescue may assist in preventing extinction of this unique Leadbeater's possum population. © 2020 John Wiley & Sons Ltd
Acute cardiovascular responses during post-exercise recovery to short-term exhaustive exercise
- Zichy-Woinarski, Christopher
- Authors: Zichy-Woinarski, Christopher
- Date: 2000
- Type: Text , Thesis , Masters
- Full Text: false
- Description: "The aim of this study was to examine the effect of consecutive bouts of acute exhaustive exercise in a hot ambient environmemt on baroreflex gain, plasma volume and heart variability one week post-exercise in trained individuals." Problem with pages xviii-xx Pages 9-37 missing.
- Description: Masters of Applied Science
- Authors: Zichy-Woinarski, Christopher
- Date: 2000
- Type: Text , Thesis , Masters
- Full Text: false
- Description: "The aim of this study was to examine the effect of consecutive bouts of acute exhaustive exercise in a hot ambient environmemt on baroreflex gain, plasma volume and heart variability one week post-exercise in trained individuals." Problem with pages xviii-xx Pages 9-37 missing.
- Description: Masters of Applied Science
Teacher pedagogies of dialogic imagination - A narrative inquiry
- Authors: Zibell, Linda
- Date: 2016
- Type: Text , Thesis , PhD
- Full Text:
- Description: This thesis is a narrative inquiry to investigate teachers’ meanings for imagination and its potency for teaching and learning. Six teachers who identified it as central to their practice shared stories of how imagination is an effective pedagogy through in-depth, semi-structured interviews. Imagination is a living, mercurial phenomenon contested in philosophical circles yet taken-for-granted amongst the populace. Consequently, imagination in teaching and learning is under researched and widely regarded as mere decoration - helpful for engagement but unrelated to cognition. The literature review situates the research in international discussions concerning imagination’s value for teaching and learning. Several conceptualisations of meaning for imagination lead to a theoretical framework which re-conceptualises Bakhtin’s dialogic imagination and combines his philosophy of discourse with Ricoeur’s philosophy of imagination, and Brockmeier’s narrative imagination. Data analysis to compare and contrast the teachers’ meanings to the framework strongly suggests that, contrary to existing stereotypes, imagination is cognitive: it catalyses metaphoric meaning-making events as dialogic imagination. Since an open living discourse and narrative imagination are conditions for such meaning events, the teachers’ pedagogical choices are consequently rational and supportive of learning. Australian educational policy-makers have increasingly leveraged a closed classroom discourse over past decades: teachers must ensure students comply with national testing regimes that demand monologic responses tied to finalised syllabus requirements. Over that period students’ accomplishment has either seriously declined or flatlined. The teachers in this narrative inquiry keep living discourse and imagination open and alive but in spite of, not because of existing policy: the research presented here permits their understandings and professional art to be given voice in educational debates on effective teaching. I conclude policy makers might seriously consider the impacts of policy dynamics and whether they are slowly suffocating opportunities for a living atmosphere that invites imagination – a powerhouse of learning – into their lives.
- Description: Doctor of Philosophy
- Authors: Zibell, Linda
- Date: 2016
- Type: Text , Thesis , PhD
- Full Text:
- Description: This thesis is a narrative inquiry to investigate teachers’ meanings for imagination and its potency for teaching and learning. Six teachers who identified it as central to their practice shared stories of how imagination is an effective pedagogy through in-depth, semi-structured interviews. Imagination is a living, mercurial phenomenon contested in philosophical circles yet taken-for-granted amongst the populace. Consequently, imagination in teaching and learning is under researched and widely regarded as mere decoration - helpful for engagement but unrelated to cognition. The literature review situates the research in international discussions concerning imagination’s value for teaching and learning. Several conceptualisations of meaning for imagination lead to a theoretical framework which re-conceptualises Bakhtin’s dialogic imagination and combines his philosophy of discourse with Ricoeur’s philosophy of imagination, and Brockmeier’s narrative imagination. Data analysis to compare and contrast the teachers’ meanings to the framework strongly suggests that, contrary to existing stereotypes, imagination is cognitive: it catalyses metaphoric meaning-making events as dialogic imagination. Since an open living discourse and narrative imagination are conditions for such meaning events, the teachers’ pedagogical choices are consequently rational and supportive of learning. Australian educational policy-makers have increasingly leveraged a closed classroom discourse over past decades: teachers must ensure students comply with national testing regimes that demand monologic responses tied to finalised syllabus requirements. Over that period students’ accomplishment has either seriously declined or flatlined. The teachers in this narrative inquiry keep living discourse and imagination open and alive but in spite of, not because of existing policy: the research presented here permits their understandings and professional art to be given voice in educational debates on effective teaching. I conclude policy makers might seriously consider the impacts of policy dynamics and whether they are slowly suffocating opportunities for a living atmosphere that invites imagination – a powerhouse of learning – into their lives.
- Description: Doctor of Philosophy
Adaptive clustering with feature ranking for DDoS attacks detection
- Zi, Lifang, Yearwood, John, Wu, Xin
- Authors: Zi, Lifang , Yearwood, John , Wu, Xin
- Date: 2010
- Type: Text , Conference proceedings
- Full Text:
- Description: Distributed Denial of Service (DDoS) attacks pose an increasing threat to the current internet. The detection of such attacks plays an important role in maintaining the security of networks. In this paper, we propose a novel adaptive clustering method combined with feature ranking for DDoS attacks detection. First, based on the analysis of network traffic, preliminary variables are selected. Second, the Modified Global K-means algorithm (MGKM) is used as the basic incremental clustering algorithm to identify the cluster structure of the target data. Third, the linear correlation coefficient is used for feature ranking. Lastly, the feature ranking result is used to inform and recalculate the clusters. This adaptive process can make worthwhile adjustments to the working feature vector according to different patterns of DDoS attacks, and can improve the quality of the clusters and the effectiveness of the clustering algorithm. The experimental results demonstrate that our method is effective and adaptive in detecting the separate phases of DDoS attacks. © 2010 IEEE.
- Authors: Zi, Lifang , Yearwood, John , Wu, Xin
- Date: 2010
- Type: Text , Conference proceedings
- Full Text:
- Description: Distributed Denial of Service (DDoS) attacks pose an increasing threat to the current internet. The detection of such attacks plays an important role in maintaining the security of networks. In this paper, we propose a novel adaptive clustering method combined with feature ranking for DDoS attacks detection. First, based on the analysis of network traffic, preliminary variables are selected. Second, the Modified Global K-means algorithm (MGKM) is used as the basic incremental clustering algorithm to identify the cluster structure of the target data. Third, the linear correlation coefficient is used for feature ranking. Lastly, the feature ranking result is used to inform and recalculate the clusters. This adaptive process can make worthwhile adjustments to the working feature vector according to different patterns of DDoS attacks, and can improve the quality of the clusters and the effectiveness of the clustering algorithm. The experimental results demonstrate that our method is effective and adaptive in detecting the separate phases of DDoS attacks. © 2010 IEEE.
An application of consensus clustering for DDoS attacks detection
- Zi, Lifang, Yearwood, John, Kelarev, Andrei
- Authors: Zi, Lifang , Yearwood, John , Kelarev, Andrei
- Date: 2010
- Type: Text , Conference proceedings
- Full Text:
- Description: The detection of Distributed Denial of Service (DDos) attacks is very important for maintaining the security of networks and the Internet. This paper introduces a novel iterative consensus process based on Hybrid Bipartite Graph Formulation (HGBF) consensus function for DDos attacks detection. First, the features are extracted during feature extraction process based on the analysis of network traffic. Second, several clustering algorithms are applied in combination with the silhouette index to obtain a collection of independent initial clusterings. Third, the HGBF consensus function and silhouette index are used to find an appropriate consensus clustering of the initial clusterings. Fourth, this new consensus clustering is added to the pool of initial clusterings replacing another clustering with the worst Silhouette index. Fifth, the process continues iteratively until the Silhouette index of the resulting consensus clusterings stabilizes. This iterative consensus clustering process can improve the quality of the clusters. The experimental results demonstrate that our iterative consensus process is effective and can be used in practice for detecting the separate phased of DDos attacks.
- Authors: Zi, Lifang , Yearwood, John , Kelarev, Andrei
- Date: 2010
- Type: Text , Conference proceedings
- Full Text:
- Description: The detection of Distributed Denial of Service (DDos) attacks is very important for maintaining the security of networks and the Internet. This paper introduces a novel iterative consensus process based on Hybrid Bipartite Graph Formulation (HGBF) consensus function for DDos attacks detection. First, the features are extracted during feature extraction process based on the analysis of network traffic. Second, several clustering algorithms are applied in combination with the silhouette index to obtain a collection of independent initial clusterings. Third, the HGBF consensus function and silhouette index are used to find an appropriate consensus clustering of the initial clusterings. Fourth, this new consensus clustering is added to the pool of initial clusterings replacing another clustering with the worst Silhouette index. Fifth, the process continues iteratively until the Silhouette index of the resulting consensus clusterings stabilizes. This iterative consensus clustering process can improve the quality of the clusters. The experimental results demonstrate that our iterative consensus process is effective and can be used in practice for detecting the separate phased of DDos attacks.
Multi-label learning with emerging new labels
- Zhu, Yue, Ting, Kaiming, Zhou, Zhi-Hua
- Authors: Zhu, Yue , Ting, Kaiming , Zhou, Zhi-Hua
- Date: 2018
- Type: Text , Journal article
- Relation: IEEE Transactions on Knowledge and Data Engineering Vol. 30, no. 10 (2018), p. 1901-1914
- Full Text:
- Reviewed:
- Description: In a multi-label learning task, an object possesses multiple concepts where each concept is represented by a class label. Previous studies on multi-label learning have focused on a fixed set of class labels, i.e., the class label set of test data is the same as that in the training set. In many applications, however, the environment is dynamic and new concepts may emerge in a data stream. In order to maintain a good predictive performance in this environment, a multi-label learning method must have the ability to detect and classify instances with emerging new labels. To this end, we propose a new approach called Multi-label learning with Emerging New Labels (MuENL). It has three functions: classify instances on currently known labels, detect the emergence of a new label, and construct a new classifier for each new label that works collaboratively with the classifier for known labels. In addition, we show that MuENL can be easily extended to handle sparse high dimensional data streams by simply reducing the original dimensionality, and then applying MuENL on the reduced dimensional space. Our empirical evaluation shows the effectiveness of MuENL on several benchmark datasets and MuENLHD on the sparse high dimensional Weibo dataset.
- Authors: Zhu, Yue , Ting, Kaiming , Zhou, Zhi-Hua
- Date: 2018
- Type: Text , Journal article
- Relation: IEEE Transactions on Knowledge and Data Engineering Vol. 30, no. 10 (2018), p. 1901-1914
- Full Text:
- Reviewed:
- Description: In a multi-label learning task, an object possesses multiple concepts where each concept is represented by a class label. Previous studies on multi-label learning have focused on a fixed set of class labels, i.e., the class label set of test data is the same as that in the training set. In many applications, however, the environment is dynamic and new concepts may emerge in a data stream. In order to maintain a good predictive performance in this environment, a multi-label learning method must have the ability to detect and classify instances with emerging new labels. To this end, we propose a new approach called Multi-label learning with Emerging New Labels (MuENL). It has three functions: classify instances on currently known labels, detect the emergence of a new label, and construct a new classifier for each new label that works collaboratively with the classifier for known labels. In addition, we show that MuENL can be easily extended to handle sparse high dimensional data streams by simply reducing the original dimensionality, and then applying MuENL on the reduced dimensional space. Our empirical evaluation shows the effectiveness of MuENL on several benchmark datasets and MuENLHD on the sparse high dimensional Weibo dataset.
Canonical Dual Algorithms for Global Optimization with Applications
- Authors: Zhou, Xiaojun
- Date: 2014
- Type: Text , Thesis
- Full Text:
- Description: Canonical duality theory provides a unified framework which can transform a nonconvex primal minimization problem to a canonical dual maximization problem over a convex domain without duality gap. But the global optimality is guaranteed by a certain positive definite condition and such condition is not always satisfied. The goal of this thesis aims to explore possible techniques that can be used to solve global optimization problems based on the canonical duality theory. Firstly, an algorithmic framework for canonical duality theory is established, which shows that the canonical dual algorithms can be developed in four aspects under the positive definite condition explicitly or implicitly, namely, (i) minimizing the primal problem, (ii) maximizing the canonical dual problem, (iii) solving a nonlinear equation caused by total complementary function, and (iv) solving a nonlinear equation caused by canonical dual function. Secondly, we show that if there exists a critical point of the canonical dual problem in the positive definite domain, by solving an equivalent semidefinite programming (SDP) problem, the corresponding global solution to the primal problem can be obtained easily via off-the-shelf software packages. A specific canonical dual algorithm is given for each problem, including sum of fourth-order polynomials minimization, nonconvex quadratically constrained quadratic program (QCQP), and boolean quadratic program (BQP). Thirdly, we propose a canonical primal-dual algorithm framework based on the total complementary function. Convergence analysis is discussed from the perspective of variational inequalities (VIs) and contraction methods. Specific canonical primal-dual algorithms for sum of fourth-order polynomials minimization is given as well. And a real-world application to the sensor network localization problem is illustrated. Next, a canonical sequential reduction approach is proposed to recover the approximate or global solution for the BQP problem. By fixing some previously known components, the original problem can be reduced sequentially to a lower dimension one. This approach is successfully applied to the well-known maxcut problem. Finally, we discuss the canonical dual approach applied to continuous time constrained optimal control. And it shows that the optimal control law for the n-dimensional constrained linear quadratic regulator can be achieved precisely via one-dimensional canonical dual variable, and for the optimal control problem with concave cost functional, an approximate solution can be obtained by introducing a linear perturbation term.
- Description: PhD
- Authors: Zhou, Xiaojun
- Date: 2014
- Type: Text , Thesis
- Full Text:
- Description: Canonical duality theory provides a unified framework which can transform a nonconvex primal minimization problem to a canonical dual maximization problem over a convex domain without duality gap. But the global optimality is guaranteed by a certain positive definite condition and such condition is not always satisfied. The goal of this thesis aims to explore possible techniques that can be used to solve global optimization problems based on the canonical duality theory. Firstly, an algorithmic framework for canonical duality theory is established, which shows that the canonical dual algorithms can be developed in four aspects under the positive definite condition explicitly or implicitly, namely, (i) minimizing the primal problem, (ii) maximizing the canonical dual problem, (iii) solving a nonlinear equation caused by total complementary function, and (iv) solving a nonlinear equation caused by canonical dual function. Secondly, we show that if there exists a critical point of the canonical dual problem in the positive definite domain, by solving an equivalent semidefinite programming (SDP) problem, the corresponding global solution to the primal problem can be obtained easily via off-the-shelf software packages. A specific canonical dual algorithm is given for each problem, including sum of fourth-order polynomials minimization, nonconvex quadratically constrained quadratic program (QCQP), and boolean quadratic program (BQP). Thirdly, we propose a canonical primal-dual algorithm framework based on the total complementary function. Convergence analysis is discussed from the perspective of variational inequalities (VIs) and contraction methods. Specific canonical primal-dual algorithms for sum of fourth-order polynomials minimization is given as well. And a real-world application to the sensor network localization problem is illustrated. Next, a canonical sequential reduction approach is proposed to recover the approximate or global solution for the BQP problem. By fixing some previously known components, the original problem can be reduced sequentially to a lower dimension one. This approach is successfully applied to the well-known maxcut problem. Finally, we discuss the canonical dual approach applied to continuous time constrained optimal control. And it shows that the optimal control law for the n-dimensional constrained linear quadratic regulator can be achieved precisely via one-dimensional canonical dual variable, and for the optimal control problem with concave cost functional, an approximate solution can be obtained by introducing a linear perturbation term.
- Description: PhD
Discrete state transition algorithm for unconstrained integer optimization problems
- Zhou, Xiaojun, Gao, David, Yang, Chunhua, Gui, Weihua
- Authors: Zhou, Xiaojun , Gao, David , Yang, Chunhua , Gui, Weihua
- Date: 2016
- Type: Text , Journal article
- Relation: Neurocomputing Vol. 173, no. (2016), p. 864-874
- Full Text:
- Reviewed:
- Description: A recently new intelligent optimization algorithm called discrete state transition algorithm is considered in this study, for solving unconstrained integer optimization problems. Firstly, some key elements for discrete state transition algorithm are summarized to guide its well development. Several intelligent operators are designed for local exploitation and global exploration. Then, a dynamic adjustment strategy "risk and restoration in probability" is proposed to capture global solutions with high probability. Finally, numerical experiments are carried out to test the performance of the proposed algorithm compared with other heuristics, and they show that the similar intelligent operators can be applied to ranging from traveling salesman problem, boolean integer programming, to discrete value selection problem, which indicates the adaptability and flexibility of the proposed intelligent elements. (C) 2015 Elsevier B.V. All rights reserved.
- Authors: Zhou, Xiaojun , Gao, David , Yang, Chunhua , Gui, Weihua
- Date: 2016
- Type: Text , Journal article
- Relation: Neurocomputing Vol. 173, no. (2016), p. 864-874
- Full Text:
- Reviewed:
- Description: A recently new intelligent optimization algorithm called discrete state transition algorithm is considered in this study, for solving unconstrained integer optimization problems. Firstly, some key elements for discrete state transition algorithm are summarized to guide its well development. Several intelligent operators are designed for local exploitation and global exploration. Then, a dynamic adjustment strategy "risk and restoration in probability" is proposed to capture global solutions with high probability. Finally, numerical experiments are carried out to test the performance of the proposed algorithm compared with other heuristics, and they show that the similar intelligent operators can be applied to ranging from traveling salesman problem, boolean integer programming, to discrete value selection problem, which indicates the adaptability and flexibility of the proposed intelligent elements. (C) 2015 Elsevier B.V. All rights reserved.
Global solutions to a class of CEC benchmark constrained optimization problems
- Zhou, Xiaojun, Gao, David, Yang, Chunhua
- Authors: Zhou, Xiaojun , Gao, David , Yang, Chunhua
- Date: 2016
- Type: Text , Journal article
- Relation: Optimization Letters Vol. 10, no. 3 (2016), p. 457-472
- Full Text:
- Reviewed:
- Description: This paper aims to solve a class of CEC benchmark constrained optimization problems that have been widely studied by nature-inspired optimization algorithms. Based on canonical duality theory, these challenging problems can be reformulated as a unified canonical dual problem over a convex set, which can be solved deterministically to obtain global optimal solutions in polynomial time. Applications are illustrated by some well-known CEC benchmark problems, and comparisons with other methods have demonstrated the effectiveness of the proposed approach. © 2014, Springer-Verlag Berlin Heidelberg.
- Authors: Zhou, Xiaojun , Gao, David , Yang, Chunhua
- Date: 2016
- Type: Text , Journal article
- Relation: Optimization Letters Vol. 10, no. 3 (2016), p. 457-472
- Full Text:
- Reviewed:
- Description: This paper aims to solve a class of CEC benchmark constrained optimization problems that have been widely studied by nature-inspired optimization algorithms. Based on canonical duality theory, these challenging problems can be reformulated as a unified canonical dual problem over a convex set, which can be solved deterministically to obtain global optimal solutions in polynomial time. Applications are illustrated by some well-known CEC benchmark problems, and comparisons with other methods have demonstrated the effectiveness of the proposed approach. © 2014, Springer-Verlag Berlin Heidelberg.
Enhanced multizone single-trip sand-control system successfully treats six zones in offshore Indonesia well
- Zhou, Leon, Gunawan, Indra, Jannise, Ricki, Suire, Casey, Eiman, Tyson
- Authors: Zhou, Leon , Gunawan, Indra , Jannise, Ricki , Suire, Casey , Eiman, Tyson
- Date: 2014
- Type: Text , Conference paper
- Relation: Offshore Technology Conference Asia: Meeting the Challenges for Asia's Growth, OTC ASIA 2014 p. 1799-1808
- Full Text:
- Reviewed:
- Description: Although multiple-zone, downhole sand-control tool systems have been in use since the early 1990s, these systems had been designed for jobs that only required low-pump-rates with low-pressure differentials. Multiple-zone systems capable of high fracturing pump rates and the associated differentials only recently have been introduced to the oilfield. Although these jobs are becoming more common, most of the completions have been limited to four or five treated zones. This paper presents a case history from Indonesia in which six discrete zones in an offshore deployment were treated successfully in a single trip. The challenges for this completion were numerous. Manufacturing lead time was very short, and the system would have to be adapted to the unique requirements of the completion design and the use of new components. Since the proppant and pump rating for these systems was based on five zones, rigorous analysis was necessary to ensure that a high pump rate, high differential pressure-rated single-trip, multiple-zone sand-control tool system was capable of treating six zones and that the crossover tool would survive the erosive effects of these extreme conditions. To provide assurance of the elastomeric seal integrity of the service tool, a testing program was executed for treatments to provide tracking and verification of conditions. Procedures were prepared, and equipment was retained on hand to replace the service tools, if any leaks were evident. Since system installation experience was limited in this area, gathering sufficient knowledge and experience for system deployment had to be addressed quickly. This would require sharing of lessons learned, use of experienced personnel from previous installations, and conducting of detailed training discussions between subject matter experts and service personnel. Deployment challenges and solutions, successes experienced at the well site, and the actual performance of the operations are discussed in this paper.
- Authors: Zhou, Leon , Gunawan, Indra , Jannise, Ricki , Suire, Casey , Eiman, Tyson
- Date: 2014
- Type: Text , Conference paper
- Relation: Offshore Technology Conference Asia: Meeting the Challenges for Asia's Growth, OTC ASIA 2014 p. 1799-1808
- Full Text:
- Reviewed:
- Description: Although multiple-zone, downhole sand-control tool systems have been in use since the early 1990s, these systems had been designed for jobs that only required low-pump-rates with low-pressure differentials. Multiple-zone systems capable of high fracturing pump rates and the associated differentials only recently have been introduced to the oilfield. Although these jobs are becoming more common, most of the completions have been limited to four or five treated zones. This paper presents a case history from Indonesia in which six discrete zones in an offshore deployment were treated successfully in a single trip. The challenges for this completion were numerous. Manufacturing lead time was very short, and the system would have to be adapted to the unique requirements of the completion design and the use of new components. Since the proppant and pump rating for these systems was based on five zones, rigorous analysis was necessary to ensure that a high pump rate, high differential pressure-rated single-trip, multiple-zone sand-control tool system was capable of treating six zones and that the crossover tool would survive the erosive effects of these extreme conditions. To provide assurance of the elastomeric seal integrity of the service tool, a testing program was executed for treatments to provide tracking and verification of conditions. Procedures were prepared, and equipment was retained on hand to replace the service tools, if any leaks were evident. Since system installation experience was limited in this area, gathering sufficient knowledge and experience for system deployment had to be addressed quickly. This would require sharing of lessons learned, use of experienced personnel from previous installations, and conducting of detailed training discussions between subject matter experts and service personnel. Deployment challenges and solutions, successes experienced at the well site, and the actual performance of the operations are discussed in this paper.
Estimation of the TBM advance rate under hard rock conditions using XGBoost and Bayesian optimization
- Zhou, Jian, Qiu, Yingui, Zhu, Shuangli, Armaghani, Danial, Khandelwal, Manoj, Mohamad, Edy
- Authors: Zhou, Jian , Qiu, Yingui , Zhu, Shuangli , Armaghani, Danial , Khandelwal, Manoj , Mohamad, Edy
- Date: 2021
- Type: Text , Journal article
- Relation: Underground Space Vol. 6, no. 5 (Oct 2021), p. 506-515
- Full Text:
- Reviewed:
- Description: The advance rate (AR) of a tunnel boring machine (TBM) under hard rock conditions is a key parameter in the successful implementation of tunneling engineering. In this study, we improved the accuracy of prediction models by employing a hybrid model of extreme gradient boosting (XGBoost) with Bayesian optimization (BO) to model the TBM AR. To develop the proposed models, 1286 sets of data were collected from the Peng Selangor Raw Water Transfer tunnel project in Malaysia. The database consists of rock mass and intact rock features, including rock mass rating, rock quality designation, weathered zone, uniaxial compressive strength, and Brazilian tensile strength. Machine specifications, including revolution per minute and thrust force, were considered to predict the TBM AR. The accuracies of the predictive models were examined using the root mean squares error (RMSE) and the coefficient of determination (R-2) between the observed and predicted yield by employing a five-fold cross-validation procedure. Results showed that the BO algorithm can capture better hyper-parameters for the XGBoost prediction model than can the default XGBoost model. The robustness and generalization of the BO-XGBoost model yielded prominent results with RMSE and R-2 values of 0.0967 and 0.9806 (for the testing phase), respectively. The results demonstrated the merits of the proposed BO-XGBoost model. In addition, variable importance through mutual information tests was applied to interpret the XGBoost model and demonstrated that machine parameters have the greatest impact as compared to rock mass and material properties.
- Authors: Zhou, Jian , Qiu, Yingui , Zhu, Shuangli , Armaghani, Danial , Khandelwal, Manoj , Mohamad, Edy
- Date: 2021
- Type: Text , Journal article
- Relation: Underground Space Vol. 6, no. 5 (Oct 2021), p. 506-515
- Full Text:
- Reviewed:
- Description: The advance rate (AR) of a tunnel boring machine (TBM) under hard rock conditions is a key parameter in the successful implementation of tunneling engineering. In this study, we improved the accuracy of prediction models by employing a hybrid model of extreme gradient boosting (XGBoost) with Bayesian optimization (BO) to model the TBM AR. To develop the proposed models, 1286 sets of data were collected from the Peng Selangor Raw Water Transfer tunnel project in Malaysia. The database consists of rock mass and intact rock features, including rock mass rating, rock quality designation, weathered zone, uniaxial compressive strength, and Brazilian tensile strength. Machine specifications, including revolution per minute and thrust force, were considered to predict the TBM AR. The accuracies of the predictive models were examined using the root mean squares error (RMSE) and the coefficient of determination (R-2) between the observed and predicted yield by employing a five-fold cross-validation procedure. Results showed that the BO algorithm can capture better hyper-parameters for the XGBoost prediction model than can the default XGBoost model. The robustness and generalization of the BO-XGBoost model yielded prominent results with RMSE and R-2 values of 0.0967 and 0.9806 (for the testing phase), respectively. The results demonstrated the merits of the proposed BO-XGBoost model. In addition, variable importance through mutual information tests was applied to interpret the XGBoost model and demonstrated that machine parameters have the greatest impact as compared to rock mass and material properties.
Proposing a novel comprehensive evaluation model for the coal burst liability in underground coal mines considering uncertainty factors
- Zhou, Jian, Chen, Chao, Wang, Mingzheng, Khandelwal, Manoj
- Authors: Zhou, Jian , Chen, Chao , Wang, Mingzheng , Khandelwal, Manoj
- Date: 2021
- Type: Text , Journal article
- Relation: International Journal of Mining Science and Technology Vol. 31, no. 5 (2021), p. 799-812
- Full Text:
- Reviewed:
- Description: Coal burst is a severe hazard that can result in fatalities and damage of facilities in underground coal mines. To address this issue, a robust unascertained combination model is proposed to study the coal burst hazard based on an updated database. Four assessment indexes are used in the model, which are the dynamic failure duration (DT), elastic energy index (WET), impact energy index (KE) and uniaxial compressive strength (RC). Four membership functions, including linear (L), parabolic (P), S and Weibull (W) functions, are proposed to measure the uncertainty level of individual index. The corresponding weights are determined through information entropy (EN), analysis hierarchy process (AHP) and synthetic weights (CW). Simultaneously, the classification criteria, including unascertained cluster (UC) and credible identification principle (CIP), are analyzed. The combination algorithm, consisting of P function, CW and CIP (P-CW-CIP), is selected as the optimal classification model in function of theory analysis and to train the samples. Ultimately, the established ensemble model is further validated through test samples with 100% accuracy. The results reveal that the hybrid model has a great potential in the coal burst hazard evaluation in underground coal mines. © 2021
- Authors: Zhou, Jian , Chen, Chao , Wang, Mingzheng , Khandelwal, Manoj
- Date: 2021
- Type: Text , Journal article
- Relation: International Journal of Mining Science and Technology Vol. 31, no. 5 (2021), p. 799-812
- Full Text:
- Reviewed:
- Description: Coal burst is a severe hazard that can result in fatalities and damage of facilities in underground coal mines. To address this issue, a robust unascertained combination model is proposed to study the coal burst hazard based on an updated database. Four assessment indexes are used in the model, which are the dynamic failure duration (DT), elastic energy index (WET), impact energy index (KE) and uniaxial compressive strength (RC). Four membership functions, including linear (L), parabolic (P), S and Weibull (W) functions, are proposed to measure the uncertainty level of individual index. The corresponding weights are determined through information entropy (EN), analysis hierarchy process (AHP) and synthetic weights (CW). Simultaneously, the classification criteria, including unascertained cluster (UC) and credible identification principle (CIP), are analyzed. The combination algorithm, consisting of P function, CW and CIP (P-CW-CIP), is selected as the optimal classification model in function of theory analysis and to train the samples. Ultimately, the established ensemble model is further validated through test samples with 100% accuracy. The results reveal that the hybrid model has a great potential in the coal burst hazard evaluation in underground coal mines. © 2021