Does an aging population influence stock markets? Evidence from New Zealand
- Hettihewa, Samanthala, Saha, Shrabani, Zhang, Hanxiong
- Authors: Hettihewa, Samanthala , Saha, Shrabani , Zhang, Hanxiong
- Date: 2018
- Type: Text , Journal article
- Relation: Economic Modelling Vol. 75, no. (2018), p. 142-158
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- Description: The effect of the aging baby-boom-cohort on asset values is extensively studied. While that effect varies by country, there are likely to be commonalities. Thus, research on a relatively small advanced open economy like New Zealand can provide insight into the general effect. In this study monthly data from 1991 to 2017 is used to examine how aging population in New Zealand affects its stock market considering key demographic and non-demographic macroeconomic variables and a new focus on fast-and-slow-moving institutional change. The results suggest that the net effect of an aging population on stock markets is insignificant. However, real GDP and foreign portfolio investment (FPI) show a positive relationship with the stock market. The findings reveal that FPI can mitigate possible negative effects from aging in an open economy. Moreover, the policy implications of the study suggest that international-factor mobility, skilled-migration policies, and technology-based productivity growth can boost stock markets.
- Authors: Hettihewa, Samanthala , Saha, Shrabani , Zhang, Hanxiong
- Date: 2018
- Type: Text , Journal article
- Relation: Economic Modelling Vol. 75, no. (2018), p. 142-158
- Full Text:
- Reviewed:
- Description: The effect of the aging baby-boom-cohort on asset values is extensively studied. While that effect varies by country, there are likely to be commonalities. Thus, research on a relatively small advanced open economy like New Zealand can provide insight into the general effect. In this study monthly data from 1991 to 2017 is used to examine how aging population in New Zealand affects its stock market considering key demographic and non-demographic macroeconomic variables and a new focus on fast-and-slow-moving institutional change. The results suggest that the net effect of an aging population on stock markets is insignificant. However, real GDP and foreign portfolio investment (FPI) show a positive relationship with the stock market. The findings reveal that FPI can mitigate possible negative effects from aging in an open economy. Moreover, the policy implications of the study suggest that international-factor mobility, skilled-migration policies, and technology-based productivity growth can boost stock markets.
Newly qualified graduate nurses’ experiences of workplace incivility in Australian hospital settings
- Mammen, Bindu, Hills, Danny, Lam, Louisa
- Authors: Mammen, Bindu , Hills, Danny , Lam, Louisa
- Date: 2018
- Type: Text , Journal article
- Relation: Collegian Vol. 25, no. 6 (2018), p. 591-599
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- Description: Background: Workplace incivility is a well-documented issue of concern known to negatively impact on new graduate nurses’ confidence, which in turn may affect the quality of patient care. However, there is lack of qualitative research that solely focuses on workplace incivility experiences of new graduate registered nurses enrolled in graduate nurse programs. Aim: This paper aims to explore new graduate nurses’ experiences of workplace incivility while enrolled in graduate nurse programs Method: A descriptive-qualitative method was used to discover the ‘who, what, and where’ of events and experiences, and assist in understanding the perceptions of newly qualified nurses, through face-to-face, in-depth interviews. After transcription, the interviews were analysed by thematic analysis. Findings: Four major themes emerged: ‘realising vulnerability’ ‘sensing self actualisation’ ‘changing expectations’ and ‘yearning for respect, support & information’. Discussion: Our interpretations of what participants said suggest that workplace incivility is an extant issue in nurses’ supportive graduate year, with the temporary employment status offered by the graduate nurse program being identified as a major contributing factor. Paradoxically, the relatively short duration of clinical rotation was also found to be a morale booster, as the new graduate nurses knew that any conflict experienced would cease, which therefore acted as a decisive factor for their continuation in nursing. Conclusion: This study has provided more depth and insight into the experiences of incivility experienced by new graduate nurses, highlighting that the role of temporary employment as a major causative element for exposure to workplace incivility. Graduate nurse programs could be strengthened, with additional support provided for each rotation and throughout the graduate year.
Newly qualified graduate nurses’ experiences of workplace incivility in Australian hospital settings
- Authors: Mammen, Bindu , Hills, Danny , Lam, Louisa
- Date: 2018
- Type: Text , Journal article
- Relation: Collegian Vol. 25, no. 6 (2018), p. 591-599
- Full Text:
- Reviewed:
- Description: Background: Workplace incivility is a well-documented issue of concern known to negatively impact on new graduate nurses’ confidence, which in turn may affect the quality of patient care. However, there is lack of qualitative research that solely focuses on workplace incivility experiences of new graduate registered nurses enrolled in graduate nurse programs. Aim: This paper aims to explore new graduate nurses’ experiences of workplace incivility while enrolled in graduate nurse programs Method: A descriptive-qualitative method was used to discover the ‘who, what, and where’ of events and experiences, and assist in understanding the perceptions of newly qualified nurses, through face-to-face, in-depth interviews. After transcription, the interviews were analysed by thematic analysis. Findings: Four major themes emerged: ‘realising vulnerability’ ‘sensing self actualisation’ ‘changing expectations’ and ‘yearning for respect, support & information’. Discussion: Our interpretations of what participants said suggest that workplace incivility is an extant issue in nurses’ supportive graduate year, with the temporary employment status offered by the graduate nurse program being identified as a major contributing factor. Paradoxically, the relatively short duration of clinical rotation was also found to be a morale booster, as the new graduate nurses knew that any conflict experienced would cease, which therefore acted as a decisive factor for their continuation in nursing. Conclusion: This study has provided more depth and insight into the experiences of incivility experienced by new graduate nurses, highlighting that the role of temporary employment as a major causative element for exposure to workplace incivility. Graduate nurse programs could be strengthened, with additional support provided for each rotation and throughout the graduate year.
Non-functional regression : A new challenge for neural networks
- Vamplew, Peter, Dazeley, Richard, Foale, Cameron, Choudhury, Tanveer
- Authors: Vamplew, Peter , Dazeley, Richard , Foale, Cameron , Choudhury, Tanveer
- Date: 2018
- Type: Text , Journal article
- Relation: Neurocomputing Vol. 314, no. (2018), p. 326-335
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- Description: This work identifies an important, previously unaddressed issue for regression based on neural networks – learning to accurately approximate problems where the output is not a function of the input (i.e. where the number of outputs required varies across input space). Such non-functional regression problems arise in a number of applications, and can not be adequately handled by existing neural network algorithms. To demonstrate the benefits possible from directly addressing non-functional regression, this paper proposes the first neural algorithm to do so – an extension of the Resource Allocating Network (RAN) which adds additional output neurons to the network structure during training. This new algorithm, called the Resource Allocating Network with Varying Output Cardinality (RANVOC), is demonstrated to be capable of learning to perform non-functional regression, on both artificially constructed data and also on the real-world task of specifying parameter settings for a plasma-spray process. Importantly RANVOC is shown to outperform not just the original RAN algorithm, but also the best possible error rates achievable by any functional form of regression.
- Authors: Vamplew, Peter , Dazeley, Richard , Foale, Cameron , Choudhury, Tanveer
- Date: 2018
- Type: Text , Journal article
- Relation: Neurocomputing Vol. 314, no. (2018), p. 326-335
- Full Text:
- Reviewed:
- Description: This work identifies an important, previously unaddressed issue for regression based on neural networks – learning to accurately approximate problems where the output is not a function of the input (i.e. where the number of outputs required varies across input space). Such non-functional regression problems arise in a number of applications, and can not be adequately handled by existing neural network algorithms. To demonstrate the benefits possible from directly addressing non-functional regression, this paper proposes the first neural algorithm to do so – an extension of the Resource Allocating Network (RAN) which adds additional output neurons to the network structure during training. This new algorithm, called the Resource Allocating Network with Varying Output Cardinality (RANVOC), is demonstrated to be capable of learning to perform non-functional regression, on both artificially constructed data and also on the real-world task of specifying parameter settings for a plasma-spray process. Importantly RANVOC is shown to outperform not just the original RAN algorithm, but also the best possible error rates achievable by any functional form of regression.
On topology optimization and canonical duality method
- Authors: Gao, David
- Date: 2018
- Type: Text , Journal article
- Relation: Computer Methods in Applied Mechanics and Engineering Vol. 341, no. (2018), p. 249-277
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- Description: Topology optimization for general materials is correctly formulated as a bi-level knapsack problem, which is considered to be NP-hard in global optimization and computer science. By using canonical duality theory (CDT) developed by the author, the linear knapsack problem can be solved analytically to obtain global optimal solution at each design iteration. Both uniqueness, existence, and NP-hardness are discussed. The novel CDT method for general topology optimization is refined and tested by both 2-D and 3-D benchmark problems. Numerical results show that without using filter and any other artificial technique, the CDT method can produce exactly 0-1 optimal density distribution with almost no checkerboard pattern. Its performance and novelty are compared with the popular SIMP and BESO approaches. Additionally, some mathematical and conceptual mistakes in literature are explicitly addressed. A brief review on the canonical duality theory for modeling multi-scale complex systems and for solving general nonconvex/discrete problems are given in Appendix. This paper demonstrates a simple truth: elegant designs come from correct model and theory. © 2018
- Authors: Gao, David
- Date: 2018
- Type: Text , Journal article
- Relation: Computer Methods in Applied Mechanics and Engineering Vol. 341, no. (2018), p. 249-277
- Full Text:
- Reviewed:
- Description: Topology optimization for general materials is correctly formulated as a bi-level knapsack problem, which is considered to be NP-hard in global optimization and computer science. By using canonical duality theory (CDT) developed by the author, the linear knapsack problem can be solved analytically to obtain global optimal solution at each design iteration. Both uniqueness, existence, and NP-hardness are discussed. The novel CDT method for general topology optimization is refined and tested by both 2-D and 3-D benchmark problems. Numerical results show that without using filter and any other artificial technique, the CDT method can produce exactly 0-1 optimal density distribution with almost no checkerboard pattern. Its performance and novelty are compared with the popular SIMP and BESO approaches. Additionally, some mathematical and conceptual mistakes in literature are explicitly addressed. A brief review on the canonical duality theory for modeling multi-scale complex systems and for solving general nonconvex/discrete problems are given in Appendix. This paper demonstrates a simple truth: elegant designs come from correct model and theory. © 2018
Scenario planning including ecosystem services for a coastal region in South Australia
- Sandhu, Harpinder, Clarke, Beverley, Baring, Ryan, Anderson, Sharolyn, Fisk, Claire
- Authors: Sandhu, Harpinder , Clarke, Beverley , Baring, Ryan , Anderson, Sharolyn , Fisk, Claire
- Date: 2018
- Type: Text , Journal article
- Relation: Ecosystem Services Vol. 31, no. (2018), p. 194-207
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- Description: Coastal regions provide vital ecosystem services for the human well-being. Rapid economic growth and increasing population in coastal regions is exerting more pressure on coastal environments. Here we develop four plausible scenarios to the year 2050 that address above issues in the northern Adelaide coastline, South Australia. Four scenarios were named after their characteristics, Lacuna, Gold Coast SA, Down to Earth, and Green & Gold. Lacuna and Gold Coast SA. Economy declined significantly in Lacuna, whereas, there is highest annual GDP growth (3.5%) in Gold Coast SA, which was closely followed by Green & Gold scenario (3%), GDP under Down to Earth grows at moderate 1.5%. There is highest population growth in Gold Coast SA followed by Green & Gold, Down to Earth and Lacuna. Gold Coast SA scenario led to high inequality as estimated by the Gini co-efficient of 0.45 compared to the current value of 0.33. Ecosystem services declined rapidly under Green & Gold and Lacuna as compared to the other two scenarios. The combination of scenario planning and ecosystem services valuation provides the capacity to guide coastal planning by illustrating enhanced social, environmental and economic benefits. © 2018 Elsevier B.V. **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Harpinder Sandhu” is provided in this record**
- Authors: Sandhu, Harpinder , Clarke, Beverley , Baring, Ryan , Anderson, Sharolyn , Fisk, Claire
- Date: 2018
- Type: Text , Journal article
- Relation: Ecosystem Services Vol. 31, no. (2018), p. 194-207
- Full Text:
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- Description: Coastal regions provide vital ecosystem services for the human well-being. Rapid economic growth and increasing population in coastal regions is exerting more pressure on coastal environments. Here we develop four plausible scenarios to the year 2050 that address above issues in the northern Adelaide coastline, South Australia. Four scenarios were named after their characteristics, Lacuna, Gold Coast SA, Down to Earth, and Green & Gold. Lacuna and Gold Coast SA. Economy declined significantly in Lacuna, whereas, there is highest annual GDP growth (3.5%) in Gold Coast SA, which was closely followed by Green & Gold scenario (3%), GDP under Down to Earth grows at moderate 1.5%. There is highest population growth in Gold Coast SA followed by Green & Gold, Down to Earth and Lacuna. Gold Coast SA scenario led to high inequality as estimated by the Gini co-efficient of 0.45 compared to the current value of 0.33. Ecosystem services declined rapidly under Green & Gold and Lacuna as compared to the other two scenarios. The combination of scenario planning and ecosystem services valuation provides the capacity to guide coastal planning by illustrating enhanced social, environmental and economic benefits. © 2018 Elsevier B.V. **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Harpinder Sandhu” is provided in this record**
Seal carrion is a predictable resource for coastal ecosystems
- Quaggiotto, Maria-Martina, Barton, Philip, Morris, Christopher, Moss, Simon, Pomeroy, Patrick
- Authors: Quaggiotto, Maria-Martina , Barton, Philip , Morris, Christopher , Moss, Simon , Pomeroy, Patrick
- Date: 2018
- Type: Text , Journal article
- Relation: Acta Oecologica Vol. 88, no. (2018), p. 41-51
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- Description: The timing, magnitude, and spatial distribution of resource inputs can have large effects on dependent organisms. Few studies have examined the predictability of such resources and no standard ecological measure of predictability exists. We examined the potential predictability of carrion resources provided by one of the UK's largest grey seal (Halichoerus grypus) colonies, on the Isle of May, Scotland. We used aerial (11 years) and ground surveys (3 years) to quantify the variability in time, space, quantity (kg), and quality (MJ) of seal carrion during the seal pupping season. We then compared the potential predictability of seal carrion to other periodic changes in food availability in nature. An average of 6893 kg of carrion ∙yr−1 corresponding to 110.5 × 103 MJ yr−1 was released for potential scavengers as placentae and dead animals. A fifth of the total biomass from dead seals was consumed by the end of the pupping season, mostly by avian scavengers. The spatial distribution of carcasses was similar across years, and 28% of the area containing >10 carcasses ha−1 was shared among all years. Relative standard errors (RSE) in space, time, quantity, and quality of carrion were all below 34%. This is similar to other allochthonous-dependent ecosystems, such as those affected by migratory salmon, and indicates high predictability of seal carrion as a resource. Our study illustrates how to quantify predictability in carrion, which is of general relevance to ecosystems that are dependent on this resource. We also highlight the importance of carrion to marine coastal ecosystems, where it sustains avian scavengers thus affecting ecosystem structure and function. © 2018 Elsevier Masson SAS. **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Philip Barton" is provided in this record**
- Authors: Quaggiotto, Maria-Martina , Barton, Philip , Morris, Christopher , Moss, Simon , Pomeroy, Patrick
- Date: 2018
- Type: Text , Journal article
- Relation: Acta Oecologica Vol. 88, no. (2018), p. 41-51
- Full Text:
- Reviewed:
- Description: The timing, magnitude, and spatial distribution of resource inputs can have large effects on dependent organisms. Few studies have examined the predictability of such resources and no standard ecological measure of predictability exists. We examined the potential predictability of carrion resources provided by one of the UK's largest grey seal (Halichoerus grypus) colonies, on the Isle of May, Scotland. We used aerial (11 years) and ground surveys (3 years) to quantify the variability in time, space, quantity (kg), and quality (MJ) of seal carrion during the seal pupping season. We then compared the potential predictability of seal carrion to other periodic changes in food availability in nature. An average of 6893 kg of carrion ∙yr−1 corresponding to 110.5 × 103 MJ yr−1 was released for potential scavengers as placentae and dead animals. A fifth of the total biomass from dead seals was consumed by the end of the pupping season, mostly by avian scavengers. The spatial distribution of carcasses was similar across years, and 28% of the area containing >10 carcasses ha−1 was shared among all years. Relative standard errors (RSE) in space, time, quantity, and quality of carrion were all below 34%. This is similar to other allochthonous-dependent ecosystems, such as those affected by migratory salmon, and indicates high predictability of seal carrion as a resource. Our study illustrates how to quantify predictability in carrion, which is of general relevance to ecosystems that are dependent on this resource. We also highlight the importance of carrion to marine coastal ecosystems, where it sustains avian scavengers thus affecting ecosystem structure and function. © 2018 Elsevier Masson SAS. **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Philip Barton" is provided in this record**
Workplace aggression experiences and responses of Victorian nurses, midwives and care personnel
- Hills, Danny, Lam, Louisa, Hills, Sharon
- Authors: Hills, Danny , Lam, Louisa , Hills, Sharon
- Date: 2018
- Type: Text , Journal article
- Relation: Collegian Vol. 25, no. 6 (2018), p. 575-582
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- Description: Background: Workplace aggression is a major work health and safety, and public health concern. To date, there has been limited investigation of population level exposure and responses to workplace aggression from all sources, and little evidence on the experiences, reporting and support-seeking behaviour of nurses, midwives and care personnel in Australian settings. Aim: To determine the 12-month prevalence of aggression experienced by nurses, midwives and care personnel from sources external and internal to the organisation, and the reporting behaviours and support sought from employers, health services, Trade Unions, work health and safety agencies, police and legal services. Methods: An online survey of the membership of the Australian Nursing and Midwifery Federation – Victorian Branch was conducted between 1 st May and 30th June 2017. Findings: In the previous 12 months, 96.5% of respondents experienced workplace aggression, with 90.9% experiencing aggression from external sources and 72.3% from internal sources. A majority indicated they just accepted incidents of aggression, and most rarely or never took time off work, sought medical or psychological treatment, or sought organisational or other institutional support, advice or action. Levels of satisfaction with institutional services were mostly neutral to poor. Discussion: Victorian nurses, midwives and care personnel work in aggressive and violent workplaces. The incivility endemic in health care likely sets the climate for the generation of and exposure to so much explicit aggression and violence. It appears that any systems or processes instituted to protect health care personnel from harm are failing. Conclusion: More targeted and effectively operationalised legislation, incentives and penalties are likely required. Further research may elaborate the extent of the impact of exposure to workplace aggression over time.
- Authors: Hills, Danny , Lam, Louisa , Hills, Sharon
- Date: 2018
- Type: Text , Journal article
- Relation: Collegian Vol. 25, no. 6 (2018), p. 575-582
- Full Text:
- Reviewed:
- Description: Background: Workplace aggression is a major work health and safety, and public health concern. To date, there has been limited investigation of population level exposure and responses to workplace aggression from all sources, and little evidence on the experiences, reporting and support-seeking behaviour of nurses, midwives and care personnel in Australian settings. Aim: To determine the 12-month prevalence of aggression experienced by nurses, midwives and care personnel from sources external and internal to the organisation, and the reporting behaviours and support sought from employers, health services, Trade Unions, work health and safety agencies, police and legal services. Methods: An online survey of the membership of the Australian Nursing and Midwifery Federation – Victorian Branch was conducted between 1 st May and 30th June 2017. Findings: In the previous 12 months, 96.5% of respondents experienced workplace aggression, with 90.9% experiencing aggression from external sources and 72.3% from internal sources. A majority indicated they just accepted incidents of aggression, and most rarely or never took time off work, sought medical or psychological treatment, or sought organisational or other institutional support, advice or action. Levels of satisfaction with institutional services were mostly neutral to poor. Discussion: Victorian nurses, midwives and care personnel work in aggressive and violent workplaces. The incivility endemic in health care likely sets the climate for the generation of and exposure to so much explicit aggression and violence. It appears that any systems or processes instituted to protect health care personnel from harm are failing. Conclusion: More targeted and effectively operationalised legislation, incentives and penalties are likely required. Further research may elaborate the extent of the impact of exposure to workplace aggression over time.
Adaptive weighted non-parametric background model for efficient video coding
- Chakraborty, Subrata, Paul, Manoranjan, Murshed, Manzur, Ali, Mortuza
- Authors: Chakraborty, Subrata , Paul, Manoranjan , Murshed, Manzur , Ali, Mortuza
- Date: 2017
- Type: Text , Journal article
- Relation: Neurocomputing Vol. 226, no. (2017), p. 35-45
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- Description: Dynamic background frame based video coding using mixture of Gaussian (MoG) based background modelling has achieved better rate distortion performance compared to the H.264 standard. However, they suffer from high computation time, low coding efficiency for dynamic videos, and prior knowledge requirement of video content. In this paper, we introduce the application of the non-parametric (NP) background modelling approach for video coding domain. We present a novel background modelling technique, called weighted non-parametric (WNP) which balances the historical trend and the recent value of the pixel intensities adaptively based on the content and characteristics of any particular video. WNP is successfully embedded into the latest HEVC video coding standard for better rate-distortion performance. Moreover, a novel scene adaptive non-parametric (SANP) technique is also developed to handle video sequences with high dynamic background. Being non-parametric, the proposed techniques naturally exhibit superior performance in dynamic background modelling without a priori knowledge of video data distribution.
- Authors: Chakraborty, Subrata , Paul, Manoranjan , Murshed, Manzur , Ali, Mortuza
- Date: 2017
- Type: Text , Journal article
- Relation: Neurocomputing Vol. 226, no. (2017), p. 35-45
- Full Text:
- Reviewed:
- Description: Dynamic background frame based video coding using mixture of Gaussian (MoG) based background modelling has achieved better rate distortion performance compared to the H.264 standard. However, they suffer from high computation time, low coding efficiency for dynamic videos, and prior knowledge requirement of video content. In this paper, we introduce the application of the non-parametric (NP) background modelling approach for video coding domain. We present a novel background modelling technique, called weighted non-parametric (WNP) which balances the historical trend and the recent value of the pixel intensities adaptively based on the content and characteristics of any particular video. WNP is successfully embedded into the latest HEVC video coding standard for better rate-distortion performance. Moreover, a novel scene adaptive non-parametric (SANP) technique is also developed to handle video sequences with high dynamic background. Being non-parametric, the proposed techniques naturally exhibit superior performance in dynamic background modelling without a priori knowledge of video data distribution.
Improved depth coding for HEVC focusing on depth edge approximation
- Podder, Pallab, Paul, Manoranjan, Rahaman, Motiur, Murshed, Manzur
- Authors: Podder, Pallab , Paul, Manoranjan , Rahaman, Motiur , Murshed, Manzur
- Date: 2017
- Type: Text , Journal article , acceptedVersion
- Relation: Signal Processing: Image Communication Vol. 55, no. (2017), p. 80-92
- Full Text:
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- Description: The latest High Efficiency Video Coding (HEVC) standard has greatly improved the coding efficiency compared to its predecessor H.264. An important share of which is the adoption of hierarchical block partitioning structures and an extended number of modes. The structure of existing inter-modes is appropriate mainly to handle the rectangular and square aligned motion patterns. However, they could not be suitable for the block partitioning of depth objects having partial foreground motion with irregular edges and background. In such cases, the HEVC reference test model (HM) normally explores finer level block partitioning that requires more bits and encoding time to compensate large residuals. Since motion detection is the underlying criteria for mode selection, in this work, we use the energy concentration ratio feature of phase correlation to capture different types of motion in depth object. For better motion modeling focusing at depth edges, the proposed technique also uses an extra pattern mode comprising a group of templates with various rectangular and non-rectangular object shapes and edges. As the pattern mode could save bits by encoding only the foreground areas and beat all other inter-modes in a block once selected, the proposed technique could improve the rate-distortion performance. It could also reduce encoding time by skipping further branching using the pattern mode and selecting a subset of modes using innovative pre-processing criteria. Experimentally it could save 29% average encoding time and improve 0.10 dB Bjontegaard Delta peak signal-to-noise ratio compared to the HM.
- Authors: Podder, Pallab , Paul, Manoranjan , Rahaman, Motiur , Murshed, Manzur
- Date: 2017
- Type: Text , Journal article , acceptedVersion
- Relation: Signal Processing: Image Communication Vol. 55, no. (2017), p. 80-92
- Full Text:
- Reviewed:
- Description: The latest High Efficiency Video Coding (HEVC) standard has greatly improved the coding efficiency compared to its predecessor H.264. An important share of which is the adoption of hierarchical block partitioning structures and an extended number of modes. The structure of existing inter-modes is appropriate mainly to handle the rectangular and square aligned motion patterns. However, they could not be suitable for the block partitioning of depth objects having partial foreground motion with irregular edges and background. In such cases, the HEVC reference test model (HM) normally explores finer level block partitioning that requires more bits and encoding time to compensate large residuals. Since motion detection is the underlying criteria for mode selection, in this work, we use the energy concentration ratio feature of phase correlation to capture different types of motion in depth object. For better motion modeling focusing at depth edges, the proposed technique also uses an extra pattern mode comprising a group of templates with various rectangular and non-rectangular object shapes and edges. As the pattern mode could save bits by encoding only the foreground areas and beat all other inter-modes in a block once selected, the proposed technique could improve the rate-distortion performance. It could also reduce encoding time by skipping further branching using the pattern mode and selecting a subset of modes using innovative pre-processing criteria. Experimentally it could save 29% average encoding time and improve 0.10 dB Bjontegaard Delta peak signal-to-noise ratio compared to the HM.
Land rebound after banning deep groundwater extraction in Changzhou, China
- Wang, Guang-ya, Zhu, Jin-qi, You, Greg, Yu, Jun, Gong, Xu-long, Li, Wei, Gou, Fu-gang
- Authors: Wang, Guang-ya , Zhu, Jin-qi , You, Greg , Yu, Jun , Gong, Xu-long , Li, Wei , Gou, Fu-gang
- Date: 2017
- Type: Text , Journal article
- Relation: Engineering Geology Vol. 229, no. (2017), p. 13-20
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- Reviewed:
- Description: More than 30 years groundwater overdraft had resulted in hydraulic head declined from near the ground surface to 85 m deep in the second confined aquifer (CA2) in Changzhou, and lead to regional land subsidence from 1970's to early 2000's. After banning deep groundwater extraction was banned in 2000, the hydraulic head of CA2 had recovered to 37.6 m in Changzhou by the end of 2013. Based on several stages first and second order leveling results and long term monitoring data from the multi-strata borehole extensometer station (BES), it was revealed that the land subsidence is attributed to the compression of both aquifers and aquitards in the porous aquifer system. The spatial characteristics of subsidence are related not only to hydraulic head pattern in the area, but also to the thickness and compressibility of different soil strata, and distance from the aquifer. Since banning deep groundwater extraction, the ground uplifted 37.22 mm (5.4% of the pre subsidence) at BES, Changzhou due to the hydraulic head recovering. Strata compression and rebound was recorded as: the upper most stratum, and the underlying aquitard of CA2, and the upper CA3 are still in the compression process, the lower CA3 layer and the upper most segment of aquitard of CA2 rebounded about 90% of the pre compression recorded since 1984, and the CA2 and its adjacent overlying aquitard rebounded 3.8%–9.7% of the pre compression. © 2017 Elsevier B.V.
- Authors: Wang, Guang-ya , Zhu, Jin-qi , You, Greg , Yu, Jun , Gong, Xu-long , Li, Wei , Gou, Fu-gang
- Date: 2017
- Type: Text , Journal article
- Relation: Engineering Geology Vol. 229, no. (2017), p. 13-20
- Full Text:
- Reviewed:
- Description: More than 30 years groundwater overdraft had resulted in hydraulic head declined from near the ground surface to 85 m deep in the second confined aquifer (CA2) in Changzhou, and lead to regional land subsidence from 1970's to early 2000's. After banning deep groundwater extraction was banned in 2000, the hydraulic head of CA2 had recovered to 37.6 m in Changzhou by the end of 2013. Based on several stages first and second order leveling results and long term monitoring data from the multi-strata borehole extensometer station (BES), it was revealed that the land subsidence is attributed to the compression of both aquifers and aquitards in the porous aquifer system. The spatial characteristics of subsidence are related not only to hydraulic head pattern in the area, but also to the thickness and compressibility of different soil strata, and distance from the aquifer. Since banning deep groundwater extraction, the ground uplifted 37.22 mm (5.4% of the pre subsidence) at BES, Changzhou due to the hydraulic head recovering. Strata compression and rebound was recorded as: the upper most stratum, and the underlying aquitard of CA2, and the upper CA3 are still in the compression process, the lower CA3 layer and the upper most segment of aquitard of CA2 rebounded about 90% of the pre compression recorded since 1984, and the CA2 and its adjacent overlying aquitard rebounded 3.8%–9.7% of the pre compression. © 2017 Elsevier B.V.
Birds as surrogates for mammals and reptiles: Are patterns of cross-taxonomic associations stable over time in a human-modified landscape?
- Yong, Ding, Barton, Philip, Okada, Sachiko, Crane, Mason, Lindenmayer, David
- Authors: Yong, Ding , Barton, Philip , Okada, Sachiko , Crane, Mason , Lindenmayer, David
- Date: 2016
- Type: Text , Journal article
- Relation: Ecological Indicators Vol. 69, no. (2016), p. 152-164
- Full Text:
- Reviewed:
- Description: Cross-taxonomic surrogates can be feasible alternatives to direct measurements of biodiversity in conservation if validated with robust data and used with explicit goals. However, few studies of cross-taxonomic surrogates have examined how temporal changes in composition or richness in one taxon can drive variation in concordant patterns of diversity in another taxon, particularly in a dynamic and heavily modified landscape. We examined this problem by assessing changes in cross-taxonomic associations over time between the surrogate (birds) and target vertebrate taxa (mammals, reptiles) that demand high sampling effort, in a heterogeneous mosaic landscape comprising pine monoculture, eucalypt woodland remnants and agricultural land. Focussing on four study years (1999, 2001, 2011, 2013) from a dataset collected over 15 years, we: (1) investigated temporal changes in cross-taxonomic congruency among three animal taxa (2) explored how temporal variation in composition and species richness of each taxon might account for variation in cross-taxonomic congruency, and (3) identified habitat structural variables that are strongly correlated with species composition of each taxon. We found the strength of cross-taxonomic congruency varied between taxa in response to both landscape context and over time. Among the three taxa, overall correlations were weak but were consistently positive and strongest between birds and mammals, while correlations involving reptiles were usually weak and negative. We also found that stronger species richness and composition correlations between birds and mammals were not only more prevalent in woodland remnants in the agricultural matrix, but they also increased in strength over time. Temporal shifts in species composition differed in rate and extent among the taxa even though these shifts were significant over time, while important habitat structural correlates were seldom shared across taxa. Our study highlights the role of the landscape matrix and time in shaping animal communities and the resulting cross-taxonomic associations in the woodland remnants, especially after a major perturbation event (i.e. plantation establishment). In such dynamic landscapes, differing and taxon-specific shifts in species diversity over time can influence the strength, direction and consistency of cross-taxonomic correlations, therefore posing a 'temporal' problem for the use of surrogates like birds in monitoring and assessment of biodiversity, and conservation management practices in general. © 2016 Elsevier Ltd. All rights reserved.
- Authors: Yong, Ding , Barton, Philip , Okada, Sachiko , Crane, Mason , Lindenmayer, David
- Date: 2016
- Type: Text , Journal article
- Relation: Ecological Indicators Vol. 69, no. (2016), p. 152-164
- Full Text:
- Reviewed:
- Description: Cross-taxonomic surrogates can be feasible alternatives to direct measurements of biodiversity in conservation if validated with robust data and used with explicit goals. However, few studies of cross-taxonomic surrogates have examined how temporal changes in composition or richness in one taxon can drive variation in concordant patterns of diversity in another taxon, particularly in a dynamic and heavily modified landscape. We examined this problem by assessing changes in cross-taxonomic associations over time between the surrogate (birds) and target vertebrate taxa (mammals, reptiles) that demand high sampling effort, in a heterogeneous mosaic landscape comprising pine monoculture, eucalypt woodland remnants and agricultural land. Focussing on four study years (1999, 2001, 2011, 2013) from a dataset collected over 15 years, we: (1) investigated temporal changes in cross-taxonomic congruency among three animal taxa (2) explored how temporal variation in composition and species richness of each taxon might account for variation in cross-taxonomic congruency, and (3) identified habitat structural variables that are strongly correlated with species composition of each taxon. We found the strength of cross-taxonomic congruency varied between taxa in response to both landscape context and over time. Among the three taxa, overall correlations were weak but were consistently positive and strongest between birds and mammals, while correlations involving reptiles were usually weak and negative. We also found that stronger species richness and composition correlations between birds and mammals were not only more prevalent in woodland remnants in the agricultural matrix, but they also increased in strength over time. Temporal shifts in species composition differed in rate and extent among the taxa even though these shifts were significant over time, while important habitat structural correlates were seldom shared across taxa. Our study highlights the role of the landscape matrix and time in shaping animal communities and the resulting cross-taxonomic associations in the woodland remnants, especially after a major perturbation event (i.e. plantation establishment). In such dynamic landscapes, differing and taxon-specific shifts in species diversity over time can influence the strength, direction and consistency of cross-taxonomic correlations, therefore posing a 'temporal' problem for the use of surrogates like birds in monitoring and assessment of biodiversity, and conservation management practices in general. © 2016 Elsevier Ltd. All rights reserved.
Evaluating the effectiveness of overstory cover as a surrogate for bird community diversity and population trends
- Pierson, Jennifer, Mortelliti, Alessio, Barton, Philip, Lane, Peter, Lindenmayer, David
- Authors: Pierson, Jennifer , Mortelliti, Alessio , Barton, Philip , Lane, Peter , Lindenmayer, David
- Date: 2016
- Type: Text , Journal article
- Relation: Ecological Indicators Vol. 61, no. (2016), p. 790-798
- Full Text:
- Reviewed:
- Description: Landscape features are often used as surrogates for biodiversity. While landscape features may perform well as surrogates for coarse metrics of biodiversity such as species richness, their value for monitoring population trends in individual species is virtually unexplored. We compared the performance of a proposed habitat surrogate for birds, percentage cover of vegetation overstory, for two distinct aspects of bird assemblages: community diversity (i.e. species richness) and population trends. We used four different long-term studies of open woodland habitats to test the consistency of the relationship between overstory percentage cover and bird species richness across a large spatial extent (>1000 km) in Australia. We then identified twelve bird species with long-term time-series data to test the relationship between change in overstory cover and populations trends. We found percentage cover performed consistently as a surrogate for species richness in three of the four sites. However, there was no clear pattern in the performance of change in percentage cover as a surrogate for population trends. Four bird species exhibited a significant relationship with change in percentage overstory cover in one study, but this was not found across multiple studies. These results demonstrate a lack of consistency in the relationship between change in overstory cover and population trends among bird species, both within and between geographic regions. Our study demonstrates that biodiversity surrogates representing community-level metrics may be consistent across regions, but provide only limited information about individual species population trends. Understanding the limitations of the information provided by a biodiversity surrogate can inform the appropriate context for its application. Crown Copyright © 2015 Published by Elsevier Ltd. All rights reserved.
- Authors: Pierson, Jennifer , Mortelliti, Alessio , Barton, Philip , Lane, Peter , Lindenmayer, David
- Date: 2016
- Type: Text , Journal article
- Relation: Ecological Indicators Vol. 61, no. (2016), p. 790-798
- Full Text:
- Reviewed:
- Description: Landscape features are often used as surrogates for biodiversity. While landscape features may perform well as surrogates for coarse metrics of biodiversity such as species richness, their value for monitoring population trends in individual species is virtually unexplored. We compared the performance of a proposed habitat surrogate for birds, percentage cover of vegetation overstory, for two distinct aspects of bird assemblages: community diversity (i.e. species richness) and population trends. We used four different long-term studies of open woodland habitats to test the consistency of the relationship between overstory percentage cover and bird species richness across a large spatial extent (>1000 km) in Australia. We then identified twelve bird species with long-term time-series data to test the relationship between change in overstory cover and populations trends. We found percentage cover performed consistently as a surrogate for species richness in three of the four sites. However, there was no clear pattern in the performance of change in percentage cover as a surrogate for population trends. Four bird species exhibited a significant relationship with change in percentage overstory cover in one study, but this was not found across multiple studies. These results demonstrate a lack of consistency in the relationship between change in overstory cover and population trends among bird species, both within and between geographic regions. Our study demonstrates that biodiversity surrogates representing community-level metrics may be consistent across regions, but provide only limited information about individual species population trends. Understanding the limitations of the information provided by a biodiversity surrogate can inform the appropriate context for its application. Crown Copyright © 2015 Published by Elsevier Ltd. All rights reserved.
Multi-modal reliability analysis of slope stability
- Reale, Cormac, Gavin, Kenneth, Prendergast, Luke, Xue, Jianfeng
- Authors: Reale, Cormac , Gavin, Kenneth , Prendergast, Luke , Xue, Jianfeng
- Date: 2016
- Type: Text , Conference proceedings
- Relation: 6th Transport Research Arena; Warsaw, Poland; 18th-21st April 2016; published inTransportation Research Procedia Vol. 14, p. 2468-2476
- Full Text:
- Reviewed:
- Description: Probabilistic slope stability analysis typically requires an optimisation technique to locate the most probable slip surface. However, for many slopes particularly those containing many different soil layers or benches several distinct critical slip surfaces may exist. Furthermore, in large slopes these critical slip surfaces may be located at significant distances from each other. In such circumstances, finding and rehabilitating the most probable failure surface is of little merit, as rehabilitating that surface does not improve the safety of the slope as a whole. Unfortunately, existing slip surface search techniques were developed to converge on one global minimum. Therefore, to implement such methods to evaluate the stability of a slope with multiple failure mechanisms requires the user to define probable slip locations prior to calculation. This requires extensive engineering experience and places undue responsibility on the engineer in question. This paper proposes the use of a locally informed particle swarm optimisation method which is able to simultaneously converge to multiple critical slip surfaces. This optimisation model when combined with a reliability analysis is able to define all areas of concern within a slope. A case study of a railway slope is presented which highlights the benefits of the model over single objective optimisation models. The approach is of particular benefit when evaluating the stability of large existing slopes with complicated stratigraphy as these slopes are likely to contain multiple viable slip surfaces. © 2016 The Authors.
- Authors: Reale, Cormac , Gavin, Kenneth , Prendergast, Luke , Xue, Jianfeng
- Date: 2016
- Type: Text , Conference proceedings
- Relation: 6th Transport Research Arena; Warsaw, Poland; 18th-21st April 2016; published inTransportation Research Procedia Vol. 14, p. 2468-2476
- Full Text:
- Reviewed:
- Description: Probabilistic slope stability analysis typically requires an optimisation technique to locate the most probable slip surface. However, for many slopes particularly those containing many different soil layers or benches several distinct critical slip surfaces may exist. Furthermore, in large slopes these critical slip surfaces may be located at significant distances from each other. In such circumstances, finding and rehabilitating the most probable failure surface is of little merit, as rehabilitating that surface does not improve the safety of the slope as a whole. Unfortunately, existing slip surface search techniques were developed to converge on one global minimum. Therefore, to implement such methods to evaluate the stability of a slope with multiple failure mechanisms requires the user to define probable slip locations prior to calculation. This requires extensive engineering experience and places undue responsibility on the engineer in question. This paper proposes the use of a locally informed particle swarm optimisation method which is able to simultaneously converge to multiple critical slip surfaces. This optimisation model when combined with a reliability analysis is able to define all areas of concern within a slope. A case study of a railway slope is presented which highlights the benefits of the model over single objective optimisation models. The approach is of particular benefit when evaluating the stability of large existing slopes with complicated stratigraphy as these slopes are likely to contain multiple viable slip surfaces. © 2016 The Authors.
Two roles for ecological surrogacy : indicator surrogates and management surrogates
- Hunter, Malcolm, Westgate, Martin, Barton, Philip, Calhoun, Aram, Pierson, Jennifer
- Authors: Hunter, Malcolm , Westgate, Martin , Barton, Philip , Calhoun, Aram , Pierson, Jennifer
- Date: 2016
- Type: Text , Journal article
- Relation: Ecological Indicators Vol. 63, no. (2016), p. 121-125
- Full Text:
- Reviewed:
- Description: Ecological surrogacy - here defined as using a process or element (e.g., species, ecosystem, or abiotic factor) to represent another aspect of an ecological system - is a widely used concept, but many applications of the surrogate concept have been controversial. We argue that some of this controversy reflects differences among users with different goals, a distinction that can be crystalized by recognizing two basic types of surrogate. First, many ecologists and natural resource managers measure "indicator surrogates" to provide information about ecological systems. Second, and often overlooked, are "management surrogates" (e.g., umbrella species) that are primarily used to facilitate achieving management goals, especially broad goals such as "maintain biodiversity" or "increase ecosystem resilience." We propose that distinguishing these two overarching roles for surrogacy may facilitate better communication about project goals. This is critical when evaluating the usefulness of different surrogates, especially where a potential surrogate might be useful in one role but not another. Our classification for ecological surrogacy applies to species, ecosystems, ecological processes, abiotic factors, and genetics, and thus can provide coherence across a broad range of uses. © 2015 Elsevier Ltd. All rights reserved. **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Philip Barton" is provided in this record**
- Authors: Hunter, Malcolm , Westgate, Martin , Barton, Philip , Calhoun, Aram , Pierson, Jennifer
- Date: 2016
- Type: Text , Journal article
- Relation: Ecological Indicators Vol. 63, no. (2016), p. 121-125
- Full Text:
- Reviewed:
- Description: Ecological surrogacy - here defined as using a process or element (e.g., species, ecosystem, or abiotic factor) to represent another aspect of an ecological system - is a widely used concept, but many applications of the surrogate concept have been controversial. We argue that some of this controversy reflects differences among users with different goals, a distinction that can be crystalized by recognizing two basic types of surrogate. First, many ecologists and natural resource managers measure "indicator surrogates" to provide information about ecological systems. Second, and often overlooked, are "management surrogates" (e.g., umbrella species) that are primarily used to facilitate achieving management goals, especially broad goals such as "maintain biodiversity" or "increase ecosystem resilience." We propose that distinguishing these two overarching roles for surrogacy may facilitate better communication about project goals. This is critical when evaluating the usefulness of different surrogates, especially where a potential surrogate might be useful in one role but not another. Our classification for ecological surrogacy applies to species, ecosystems, ecological processes, abiotic factors, and genetics, and thus can provide coherence across a broad range of uses. © 2015 Elsevier Ltd. All rights reserved. **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Philip Barton" is provided in this record**
Looking beyond people, equipment and environment : Is a systems theory model of accident causation required to understand injuries and near misses during outdoor activities?
- Goode, Natassia, Salmon, Paul, Lenne, Michael, Finch, Caroline
- Authors: Goode, Natassia , Salmon, Paul , Lenne, Michael , Finch, Caroline
- Date: 2015
- Type: Text , Conference paper
- Relation: 6th International Conference on Applied Human Factors and Ergonomics (Ahfe 2015) and the Affiliated Conferences, Ahfe 2015; Las Vegas, USA; 26th-30th July 2015; published in Procedia Manufacturing Vol. 3, p. 1125-1131
- Relation: http://purl.org/au-research/grants/nhmrc/1058737
- Full Text:
- Reviewed:
- Description: The National Incident Database (NID) provides a standardised, industry-wide, approach to incident reporting for the outdoor sector in New Zealand (NZ). The aim of this study was to determine whether the NID contributing factor categories (i. e. people, equipment and environment) are sufficient for classifying the data that has been collected on accident causation by the NID, or whether a systems theory framework is required. A sample of injury and near miss reports (n = 228) were extracted from the NID and analysed. All contributing factors identified were classified according to Rasmussen's (1997) Risk Management Framework (RRMF), which was adapted to describe the " led outdoor activity system". In total, 58 different contributing factor categories were identified across the 228 incidents. Factors were classified across all levels of the framework, which indicates that the NID categories are inadequate. The findings also demonstrate that RRMF is appropriate for classifying the contributing factors involved in less severe injuries and near misses that do not have in-depth investigations associated with them. (C) 2015 The Authors. Published by Elsevier B.V.
- Authors: Goode, Natassia , Salmon, Paul , Lenne, Michael , Finch, Caroline
- Date: 2015
- Type: Text , Conference paper
- Relation: 6th International Conference on Applied Human Factors and Ergonomics (Ahfe 2015) and the Affiliated Conferences, Ahfe 2015; Las Vegas, USA; 26th-30th July 2015; published in Procedia Manufacturing Vol. 3, p. 1125-1131
- Relation: http://purl.org/au-research/grants/nhmrc/1058737
- Full Text:
- Reviewed:
- Description: The National Incident Database (NID) provides a standardised, industry-wide, approach to incident reporting for the outdoor sector in New Zealand (NZ). The aim of this study was to determine whether the NID contributing factor categories (i. e. people, equipment and environment) are sufficient for classifying the data that has been collected on accident causation by the NID, or whether a systems theory framework is required. A sample of injury and near miss reports (n = 228) were extracted from the NID and analysed. All contributing factors identified were classified according to Rasmussen's (1997) Risk Management Framework (RRMF), which was adapted to describe the " led outdoor activity system". In total, 58 different contributing factor categories were identified across the 228 incidents. Factors were classified across all levels of the framework, which indicates that the NID categories are inadequate. The findings also demonstrate that RRMF is appropriate for classifying the contributing factors involved in less severe injuries and near misses that do not have in-depth investigations associated with them. (C) 2015 The Authors. Published by Elsevier B.V.
Geoelectrical prospecting of glauberite deposits in the Ebro basin (Spain)
- Guinea, Ander, Playà, Elisabet, Rivero, Lluís, Salvany, Josep
- Authors: Guinea, Ander , Playà, Elisabet , Rivero, Lluís , Salvany, Josep
- Date: 2014
- Type: Text , Journal article
- Relation: Engineering Geology Vol. 174, no. (2014), p. 73-86
- Full Text:
- Reviewed:
- Description: Glauberite (Na2Ca[SO4]2) is an evaporitic mineral which is used in the industries of detergents, paper, glass, pharmacy, etc. Glauberite rocks are seldom found cropping out because they are very sensitive to weathering processes; for this reason their prospection is conducted by means of boreholes. Nowadays, geophysical techniques are not used to support the characterization of glauberite deposits due to the lack of knowledge of their physical properties.In this study geoelectrical methods are proposed as alternative techniques in the early stages of glauberite prospecting. Several glauberite units have been studied in different parts of the Ebro basin (Spain) by means of electrical resistivity tomography sections. The electrical resistivity range showed by glauberite deposits has been found to be low (10–100Ω·m) when the matrix component (clay and microcrystalline carbonates) is above 45% of the bulk composition of the rock. This type of rocks has been studied in Montes de Torrero (Zaragoza) and is the most common glauberite deposit case. Besides matrix-rich glauberite rocks, an exceptional case of a pure glauberite layer has been studied in Alcanadre (La Rioja). From this site, it has been estimated that deposits with glauberite crystal fraction close to 100% show a resistivity range of at least 3×103Ω·m.Using this extreme value as reference, the Hashin–Shtrikman bounds have been calculated for glauberite rocks considering that they are constituted of four phases (glauberite, gypsum, anhydrite and matrix). When the matrix fraction represents 45% or more of the bulk rock, the resistivity range will be that of the lower Hashin–Shtrikman bound, which is similar for any combination of sulfate (glauberite, gypsum and/or anhydrite) composition; hence, it can be considered as a two-phase system (matrix and sulfate). For rocks with less than 30% of matrix fraction, the upper Hashin–Shtrikman bound trend must be considered; however, the resistivity values overlap, making it impossible to establish a classification. Between 30 and 45% of matrix fraction, there is a transitional domain.Additionally, some theoretical models representing the most common structures in sulfate rocks have been elaborated in order to help in the interpretation of the inverted resistivity images obtained from the field data. Some artifacts generated by the complexity of the resistivity distribution of the terrain have been identified in both data sets. •Glauberite deposits are studied by means of electrical resistivity tomography.•The results of electrical imaging are compared with borehole cores.•Models representing typical structures in sulfates are compared with field results.•The electrical response of glauberite rocks for different compositions is defined.
- Authors: Guinea, Ander , Playà, Elisabet , Rivero, Lluís , Salvany, Josep
- Date: 2014
- Type: Text , Journal article
- Relation: Engineering Geology Vol. 174, no. (2014), p. 73-86
- Full Text:
- Reviewed:
- Description: Glauberite (Na2Ca[SO4]2) is an evaporitic mineral which is used in the industries of detergents, paper, glass, pharmacy, etc. Glauberite rocks are seldom found cropping out because they are very sensitive to weathering processes; for this reason their prospection is conducted by means of boreholes. Nowadays, geophysical techniques are not used to support the characterization of glauberite deposits due to the lack of knowledge of their physical properties.In this study geoelectrical methods are proposed as alternative techniques in the early stages of glauberite prospecting. Several glauberite units have been studied in different parts of the Ebro basin (Spain) by means of electrical resistivity tomography sections. The electrical resistivity range showed by glauberite deposits has been found to be low (10–100Ω·m) when the matrix component (clay and microcrystalline carbonates) is above 45% of the bulk composition of the rock. This type of rocks has been studied in Montes de Torrero (Zaragoza) and is the most common glauberite deposit case. Besides matrix-rich glauberite rocks, an exceptional case of a pure glauberite layer has been studied in Alcanadre (La Rioja). From this site, it has been estimated that deposits with glauberite crystal fraction close to 100% show a resistivity range of at least 3×103Ω·m.Using this extreme value as reference, the Hashin–Shtrikman bounds have been calculated for glauberite rocks considering that they are constituted of four phases (glauberite, gypsum, anhydrite and matrix). When the matrix fraction represents 45% or more of the bulk rock, the resistivity range will be that of the lower Hashin–Shtrikman bound, which is similar for any combination of sulfate (glauberite, gypsum and/or anhydrite) composition; hence, it can be considered as a two-phase system (matrix and sulfate). For rocks with less than 30% of matrix fraction, the upper Hashin–Shtrikman bound trend must be considered; however, the resistivity values overlap, making it impossible to establish a classification. Between 30 and 45% of matrix fraction, there is a transitional domain.Additionally, some theoretical models representing the most common structures in sulfate rocks have been elaborated in order to help in the interpretation of the inverted resistivity images obtained from the field data. Some artifacts generated by the complexity of the resistivity distribution of the terrain have been identified in both data sets. •Glauberite deposits are studied by means of electrical resistivity tomography.•The results of electrical imaging are compared with borehole cores.•Models representing typical structures in sulfates are compared with field results.•The electrical response of glauberite rocks for different compositions is defined.
Extraction and processing of real time strain of embedded FBG sensors using a fixed filter FBG circuit and an artificial neural network
- Kahandawa, Gayan, Epaarachchi, Jayantha, Wang, Hao, Canning, John, Lau, Alan
- Authors: Kahandawa, Gayan , Epaarachchi, Jayantha , Wang, Hao , Canning, John , Lau, Alan
- Date: 2013
- Type: Text , Journal article
- Relation: Measurement: Journal of the International Measurement Confederation Vol. 46, no. 10 (2013), p. 4045-4051
- Full Text:
- Reviewed:
- Description: Fibre Bragg Grating (FBG) sensors have been used in the development of structural health monitoring (SHM) and damage detection systems for advanced composite structures over several decades. Unfortunately, to date only a handful of appropriate configurations and algorithm sare available for using in SHM systems have been developed. This paper reveals a novel configuration of FBG sensors to acquire strain reading and an integrated statistical approach to analyse data in real time. The proposed configuration has proven its capability to overcome practical constraints and the engineering challenges associated with FBG-based SHM systems. A fixed filter decoding system and an integrated artificial neural network algorithm for extracting strain from embedded FBG sensor were proposed and experimentally proved. Furthermore, the laboratory level experimental data was used to verify the accuracy of the system and it was found that the error levels were less than 0.3% in predictions. The developed SMH system using this technology has been submitted to US patent office and will be available for use of aerospace applications in due course. © 2013 Elsevier Ltd. All rights reserved.
- Authors: Kahandawa, Gayan , Epaarachchi, Jayantha , Wang, Hao , Canning, John , Lau, Alan
- Date: 2013
- Type: Text , Journal article
- Relation: Measurement: Journal of the International Measurement Confederation Vol. 46, no. 10 (2013), p. 4045-4051
- Full Text:
- Reviewed:
- Description: Fibre Bragg Grating (FBG) sensors have been used in the development of structural health monitoring (SHM) and damage detection systems for advanced composite structures over several decades. Unfortunately, to date only a handful of appropriate configurations and algorithm sare available for using in SHM systems have been developed. This paper reveals a novel configuration of FBG sensors to acquire strain reading and an integrated statistical approach to analyse data in real time. The proposed configuration has proven its capability to overcome practical constraints and the engineering challenges associated with FBG-based SHM systems. A fixed filter decoding system and an integrated artificial neural network algorithm for extracting strain from embedded FBG sensor were proposed and experimentally proved. Furthermore, the laboratory level experimental data was used to verify the accuracy of the system and it was found that the error levels were less than 0.3% in predictions. The developed SMH system using this technology has been submitted to US patent office and will be available for use of aerospace applications in due course. © 2013 Elsevier Ltd. All rights reserved.