Pub Date : 2023-08-01DOI: 10.36334/modsim.2023.cunningham
L. Cunningham, James Hilton, M. Rudman
: Fire whirls are often created during wildfires on, or around, the head of the fire. These intense vertically oriented vortices have the potential to cause significant destruction by uprooting vegetation and breaking limbs from trees (Graham, 1955), creating projectiles hazardous to firefighters and ejecting burning debris in a complex pattern. Whirls may involve and contribute to flaming regions, but are more commonly comprised of smoke, hot gases and unburned fuel. The behaviour and formation mechanism of a whirl depends on its location with respect to the fire as well as the initial source of vorticity. Most often studied are stationary whirls that form directly over the burning area when subject to an external source of vorticity such as on the lee side of an obstruction to wind. Stationary whirls have been well characterised however less attention has been given to the mobile whirls which form periodically on the lee side of a fire plume and move downwind in a manner qualitatively similar to wake vortices. Despite being commonly observed the conditions necessary for the formation of the most hazardous whirls, with the strongest wind speeds, are not fully understood (Shinohara, 2022). A model for simulating fire whirls was developed in the open source-computational fluid dynamics (CFD) package OpenFOAM utilising a Large Eddy Simulation (LES) approach. This approach allowed the full dynamics of the plume, resultant whirls, thermal transport and advection of particles (representing debris or embers) to be simulated. As the focus of study was fire-induced flows such as fire whirls, rather than the fire itself, combustion was modelled as a static volumetric heat source. The model was validated against data from a small-scale wind tunnel experiment and qualitatively compared against video footage of fire whirls from a large-scale fire from the Burning Man festival. Whirl core diameter and tangential velocity matched data from the wind tunnel experiment and there was good agreement in the case of the Burning Man fire in terms of whirl frequency and qualitative visual comparison. The model is suitable for further study of the fundamental behaviour of these fire whirls from both large and small-scale simulated fires. Detailed numerical study of these whirls will aid in better understanding of how their formation mechanism and properties are related to environmental factors such as topology, wind speed, fire shape and intensity as well as understanding the distribution patterns of debris and embers transported in these structures.
火灾时，在火头上或火头周围经常会产生火旋风。这些强烈的垂直涡旋有可能通过连根拔起植被和折断树木的枝干来造成重大破坏(Graham, 1955)，产生对消防员有危险的弹射物，并以复杂的模式喷出燃烧的碎片。漩涡可能涉及并促成燃烧区域，但更常见的是由烟雾，热气体和未燃烧的燃料组成。旋涡的行为和形成机制取决于其相对于火的位置以及涡度的初始来源。最常被研究的是静止的旋涡，当受到外部涡量源的影响时，如在风力障碍的背风面，这种旋涡直接在燃烧区域上空形成。静止旋涡已经被很好地描述了，然而，很少有人注意到在火羽的背风侧周期性形成的移动旋涡，它们以一种定性类似于尾流旋涡的方式向下风移动。尽管人们经常观察到，形成最危险的漩涡所需的条件，以及最强的风速，还没有完全了解(Shinohara, 2022)。利用大涡模拟(LES)方法，在开源计算流体动力学(CFD)软件包OpenFOAM中开发了一个模拟火涡的模型。这种方法可以模拟羽流的完整动力学、产生的漩涡、热传输和粒子(代表碎片或余烬)的平流。由于研究的重点是火引起的流动，如火漩涡，而不是火本身，燃烧被建模为静态体积热源。该模型通过小型风洞实验的数据进行了验证，并与火人节(Burning Man festival)大规模火灾的火焰漩涡视频片段进行了定性比较。旋涡核心直径和切向速度与风洞实验数据相匹配，并且在Burning Man火灾的情况下，在旋涡频率和定性视觉比较方面有很好的一致性。该模型适用于从大型和小型模拟火灾中进一步研究这些火涡的基本行为。对这些漩涡进行详细的数值研究将有助于更好地了解它们的形成机制和性质与拓扑结构、风速、火的形状和强度等环境因素的关系，以及了解在这些结构中运输的碎片和余烬的分布模式。
{"title":"Modelling the dynamics of fire whirls","authors":"L. Cunningham, James Hilton, M. Rudman","doi":"10.36334/modsim.2023.cunningham","DOIUrl":"https://doi.org/10.36334/modsim.2023.cunningham","url":null,"abstract":": Fire whirls are often created during wildfires on, or around, the head of the fire. These intense vertically oriented vortices have the potential to cause significant destruction by uprooting vegetation and breaking limbs from trees (Graham, 1955), creating projectiles hazardous to firefighters and ejecting burning debris in a complex pattern. Whirls may involve and contribute to flaming regions, but are more commonly comprised of smoke, hot gases and unburned fuel. The behaviour and formation mechanism of a whirl depends on its location with respect to the fire as well as the initial source of vorticity. Most often studied are stationary whirls that form directly over the burning area when subject to an external source of vorticity such as on the lee side of an obstruction to wind. Stationary whirls have been well characterised however less attention has been given to the mobile whirls which form periodically on the lee side of a fire plume and move downwind in a manner qualitatively similar to wake vortices. Despite being commonly observed the conditions necessary for the formation of the most hazardous whirls, with the strongest wind speeds, are not fully understood (Shinohara, 2022). A model for simulating fire whirls was developed in the open source-computational fluid dynamics (CFD) package OpenFOAM utilising a Large Eddy Simulation (LES) approach. This approach allowed the full dynamics of the plume, resultant whirls, thermal transport and advection of particles (representing debris or embers) to be simulated. As the focus of study was fire-induced flows such as fire whirls, rather than the fire itself, combustion was modelled as a static volumetric heat source. The model was validated against data from a small-scale wind tunnel experiment and qualitatively compared against video footage of fire whirls from a large-scale fire from the Burning Man festival. Whirl core diameter and tangential velocity matched data from the wind tunnel experiment and there was good agreement in the case of the Burning Man fire in terms of whirl frequency and qualitative visual comparison. The model is suitable for further study of the fundamental behaviour of these fire whirls from both large and small-scale simulated fires. Detailed numerical study of these whirls will aid in better understanding of how their formation mechanism and properties are related to environmental factors such as topology, wind speed, fire shape and intensity as well as understanding the distribution patterns of debris and embers transported in these structures.","PeriodicalId":390064,"journal":{"name":"MODSIM2023, 25th International Congress on Modelling and Simulation.","volume":"97 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122779977","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-01DOI: 10.36334/modsim.2023.cichota622
R. Cichota, E. Khaembah, S. Thomas, L. Lilburne, S. Vickers, P. Omondiagbe, A. Tait
: In New Zealand, policy makers and land stewards are under pressure to change farming practices and to limit their environmental impact. Having information on such impacts is crucial for guiding policy setting and to help making decisions regarding land use change and improving management. We employed the latest advances in biophysical parameters databases, simulation modelling, and computing automation tools to develop simulations of crop rotations for all growing regions in New Zealand. The aim is to provide improved estimates of nutrient losses from cropped farmlands with a wide coverage across the country. We present here the methodology and developments made to streamline the supply of parameters and inputs to the model, the automatic creation of simulations of a variety of cropping systems, and the running of thousands of simulations in a high-performance computing (HPC) environment. These simulations were set up using the Agricultural Production Systems Simulator (APSIM). The developments include:
{"title":"Simulating crop rotations to improve estimates of nutrient losses using APSIM in HPC","authors":"R. Cichota, E. Khaembah, S. Thomas, L. Lilburne, S. Vickers, P. Omondiagbe, A. Tait","doi":"10.36334/modsim.2023.cichota622","DOIUrl":"https://doi.org/10.36334/modsim.2023.cichota622","url":null,"abstract":": In New Zealand, policy makers and land stewards are under pressure to change farming practices and to limit their environmental impact. Having information on such impacts is crucial for guiding policy setting and to help making decisions regarding land use change and improving management. We employed the latest advances in biophysical parameters databases, simulation modelling, and computing automation tools to develop simulations of crop rotations for all growing regions in New Zealand. The aim is to provide improved estimates of nutrient losses from cropped farmlands with a wide coverage across the country. We present here the methodology and developments made to streamline the supply of parameters and inputs to the model, the automatic creation of simulations of a variety of cropping systems, and the running of thousands of simulations in a high-performance computing (HPC) environment. These simulations were set up using the Agricultural Production Systems Simulator (APSIM). The developments include:","PeriodicalId":390064,"journal":{"name":"MODSIM2023, 25th International Congress on Modelling and Simulation.","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122458216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-01DOI: 10.36334/modsim.2023.costello
R. Costello, J. Little
: The family of societal challenges of the Anthropocene (e.g., climate change and impacts, renewable energy, adaptive infrastructure, disasters, pandemics, food insecurity and biodiversity loss) are numerous and daunting. Addressing these problems requires an interdisciplinary systems-thinking approach that coordinates problem-solving between practitioners of varied disciplines including engineers, physical scientists, economists and other social scientists. Civil and environmental engineers have distinct technical skills necessary to help address these challenges as part of coordinated multidisciplinary efforts, but training for this multidisciplinary exchange requires incorporation of systems-thinking into academic curricula. This research expands upon the existing literature regarding incorporation of systems-thinking into civil and environmental engineering coursework through development, implementation and subsequent evaluation of educational modules based on system dynamics models and modelling concepts. The modules consist of lecture materials, in-class exercises, homework assignments and a capstone course project based on several system dynamics models. Four educational modules were developed and deployed in the Sustainable Systems course (CEE 4134/5114) in the Civil and Environmental Engineering (CEE) department at Virginia Tech. The evaluation of module effectiveness was performed via surveys that were given pre and post module delivery and were used to determine whether there was a statistically significant change in learning outcomes. An established tool, the Lake Urmia Vignette (LUV), was used to determine the effectiveness of the modules as tools for educating CEE students in systems-thinking concepts. The results suggest that the modules are effective in improving systems-thinking learning including student ability to identify cause-and-effect variables, causal links, and feedback loops. This outcome was associated primarily with domestic students and students that had higher initial scores on the LUV survey given at the beginning of each semester. These results are interesting and introduce new questions such as why the domestic students performed better than their international counterparts. A more detailed set of demographic questions may provide additional insight necessary to identify specific strengths and weaknesses within the educational modules. Questions regarding proficiency with English as a first or second language as well as familiarity with causal link and feedback loop concepts would likely improve the resolution of the data on student populations that are assessed using these educational and assessment tools. The results also indicate some limitations with the modules that require further investigation. First, the education modules need some improvement with respect to stock and flow concepts. Students did not appear to increase learning outcomes on these topics. Second, although the results indicated a strong asso
{"title":"Development and evaluation of system dynamics education modules for socioenvironmental systems","authors":"R. Costello, J. Little","doi":"10.36334/modsim.2023.costello","DOIUrl":"https://doi.org/10.36334/modsim.2023.costello","url":null,"abstract":": The family of societal challenges of the Anthropocene (e.g., climate change and impacts, renewable energy, adaptive infrastructure, disasters, pandemics, food insecurity and biodiversity loss) are numerous and daunting. Addressing these problems requires an interdisciplinary systems-thinking approach that coordinates problem-solving between practitioners of varied disciplines including engineers, physical scientists, economists and other social scientists. Civil and environmental engineers have distinct technical skills necessary to help address these challenges as part of coordinated multidisciplinary efforts, but training for this multidisciplinary exchange requires incorporation of systems-thinking into academic curricula. This research expands upon the existing literature regarding incorporation of systems-thinking into civil and environmental engineering coursework through development, implementation and subsequent evaluation of educational modules based on system dynamics models and modelling concepts. The modules consist of lecture materials, in-class exercises, homework assignments and a capstone course project based on several system dynamics models. Four educational modules were developed and deployed in the Sustainable Systems course (CEE 4134/5114) in the Civil and Environmental Engineering (CEE) department at Virginia Tech. The evaluation of module effectiveness was performed via surveys that were given pre and post module delivery and were used to determine whether there was a statistically significant change in learning outcomes. An established tool, the Lake Urmia Vignette (LUV), was used to determine the effectiveness of the modules as tools for educating CEE students in systems-thinking concepts. The results suggest that the modules are effective in improving systems-thinking learning including student ability to identify cause-and-effect variables, causal links, and feedback loops. This outcome was associated primarily with domestic students and students that had higher initial scores on the LUV survey given at the beginning of each semester. These results are interesting and introduce new questions such as why the domestic students performed better than their international counterparts. A more detailed set of demographic questions may provide additional insight necessary to identify specific strengths and weaknesses within the educational modules. Questions regarding proficiency with English as a first or second language as well as familiarity with causal link and feedback loop concepts would likely improve the resolution of the data on student populations that are assessed using these educational and assessment tools. The results also indicate some limitations with the modules that require further investigation. First, the education modules need some improvement with respect to stock and flow concepts. Students did not appear to increase learning outcomes on these topics. Second, although the results indicated a strong asso","PeriodicalId":390064,"journal":{"name":"MODSIM2023, 25th International Congress on Modelling and Simulation.","volume":"639 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121986257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-01DOI: 10.36334/modsim.2023.yang393
J. Yang, D. White, J. Palma, D. Meason, F. Balocchi, C. Rajanayaka, W. Dawes, M. Battaglia
: Forests play a major role in regulating the global carbon cycle and the hydrologic cycle, global warming, and forest production. This poses a big challenge for forest catchment management, as it requires addressing several questions, e.g. what is the impact of deforestation and reforestation on hydrologic processes (e.g. evaporation, streamflow, groundwater system, and flooding), and what is the impact of climate change on hydrologic processes (evaporation, streamflow, etc) and forest production. This often requires a holistic understanding the interactions among climate, geology, tree growth, nutrient, and both surface and groundwater bodies. In this study, we integrated a forest hydrologic model CABALA (Battaglia et al. 2004) with a groundwater model (Pauwels et al. 2002) to simulate these interactions. This integrated model was then applied in two forest experimental catchments in Chile, i.e. Maria Las Cruces and Quivolgo with drainage areas of 19 ha and 40 ha (Balocchi et al. 2002), respectively, where water resources and forest production are of major concerns. Results indicate the integrated model can correctly simulate forest growth, catchment evapotranspiration and streamflow. Sensitivity analysis indicates that parameters of tree species and forest growth, soil (e.g. hydraulic conductivity), and topography (e.g. catchment slope) have the most impact on the streamflow. The integration of these models seems promising to support the management of forest catchments that need to consider a more holistic approach regarding water management.
森林在调节全球碳循环和水文循环、全球变暖和森林生产方面发挥着重要作用。这对森林集水区管理提出了巨大挑战，因为它需要解决几个问题，例如，毁林和再造林对水文过程(如蒸发、河流、地下水系统和洪水)的影响，以及气候变化对水文过程(蒸发、河流等)和森林生产的影响。这通常需要对气候、地质、树木生长、营养以及地表水和地下水之间的相互作用有一个全面的了解。在本研究中，我们将森林水文模型CABALA (Battaglia et al. 2004)与地下水模型(Pauwels et al. 2002)结合起来模拟这些相互作用。然后将该综合模型应用于智利的两个森林实验集水区，即Maria Las Cruces和Quivolgo，流域面积分别为19公顷和40公顷(Balocchi et al. 2002)，其中水资源和森林生产是主要问题。结果表明，该模型能较好地模拟森林生长、流域蒸散量和河流流量。敏感性分析表明，树种和森林生长、土壤(如导电性)和地形(如流域坡度)等参数对河流流量的影响最大。这些模式的整合似乎有希望支持森林集水区的管理，这些集水区需要考虑对水管理采取更全面的办法。
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Pub Date : 2023-08-01DOI: 10.36334/modsim.2023.welch468
M. Welch, Sharifah Alzubaidi, T. Schaerf
: Flocking sheep can produce impressive visual displays with movements that are synchronized and coordinated, allowing the group moving as a cohesive unit. These movement patterns emerge without a central point of control and are shaped by the interactions and decisions of the individuals participating in the flock. Collective movement serves a functional purpose, as it allows the flock to move efficiently and stay together, providing protection from predators by diluting the risk of attack to the individuals. This study builds upon previous work (Ginelli et al., 2015) by investigating the emergent collective movement properties exhibited by small flocks of sheep and inferring the underlying interactions that drive the observed emergent behaviours. Data was collected from three randomly selected flocks of four individuals using collar-mounted, Real-Time Kinematic (RTK) satellite navigation receivers running at a sample rate of 10Hz. The flocks were left grazing pasture un-interrupted and isolated from other sheep across the observation period of 1-day each. The resulting dataset contains a mixture of flock-level behaviour including actively grazing/foraging and marching between locations in the pasture. The data was transformed using the Universal Transverse Mercator (UTM) coordinate system and the polarisation and angular momentum order parameters (which measure the degree of alignment between individuals and group rotation respectively), along with the mean group speed and the area of the flock’s convex hull were calculated for each time step to characterise the emergent group-level behaviour. The changes in speed and direction of motion for all possible pairs of sheep were calculated at each time step, breaking them down into component form. This method has been extensively detailed in previous studies (Mudaliar and Schaerf, 2020) and is applied here to map the social forces that govern each individuals motion in response to the relative position of flock mates. An agent-based collective motion model was then developed to simulate that movement dynamics of a small flock in the grazing state. This model captures a range parameters that control individual motion, such as movement speed, maximum turning speeds and distances over which individuals experience social forces (e.g. repulsion/attraction). A sensitivity analysis was conducted to understand the impact of these parameter on the emergent properties. The initial findings from this study show that the flock exhibits two key collective states. The flock adopts either a highly ordered marching state where the flock moves at a higher mean speed (ranging from 0.5 through 1.5msec -1 ) with high polarisation/low angular momentum or a grazing state with a lower mean group speed (ranging from 0.0 through 0.5msec -1 ) and a lower degree of collective order with a wider distribution of polarisation/angular momentum values. The grazing state is characterised by a pattern of expansion and contraction of
{"title":"Modelling collective states and individual-level interactions in small sheep flocks","authors":"M. Welch, Sharifah Alzubaidi, T. Schaerf","doi":"10.36334/modsim.2023.welch468","DOIUrl":"https://doi.org/10.36334/modsim.2023.welch468","url":null,"abstract":": Flocking sheep can produce impressive visual displays with movements that are synchronized and coordinated, allowing the group moving as a cohesive unit. These movement patterns emerge without a central point of control and are shaped by the interactions and decisions of the individuals participating in the flock. Collective movement serves a functional purpose, as it allows the flock to move efficiently and stay together, providing protection from predators by diluting the risk of attack to the individuals. This study builds upon previous work (Ginelli et al., 2015) by investigating the emergent collective movement properties exhibited by small flocks of sheep and inferring the underlying interactions that drive the observed emergent behaviours. Data was collected from three randomly selected flocks of four individuals using collar-mounted, Real-Time Kinematic (RTK) satellite navigation receivers running at a sample rate of 10Hz. The flocks were left grazing pasture un-interrupted and isolated from other sheep across the observation period of 1-day each. The resulting dataset contains a mixture of flock-level behaviour including actively grazing/foraging and marching between locations in the pasture. The data was transformed using the Universal Transverse Mercator (UTM) coordinate system and the polarisation and angular momentum order parameters (which measure the degree of alignment between individuals and group rotation respectively), along with the mean group speed and the area of the flock’s convex hull were calculated for each time step to characterise the emergent group-level behaviour. The changes in speed and direction of motion for all possible pairs of sheep were calculated at each time step, breaking them down into component form. This method has been extensively detailed in previous studies (Mudaliar and Schaerf, 2020) and is applied here to map the social forces that govern each individuals motion in response to the relative position of flock mates. An agent-based collective motion model was then developed to simulate that movement dynamics of a small flock in the grazing state. This model captures a range parameters that control individual motion, such as movement speed, maximum turning speeds and distances over which individuals experience social forces (e.g. repulsion/attraction). A sensitivity analysis was conducted to understand the impact of these parameter on the emergent properties. The initial findings from this study show that the flock exhibits two key collective states. The flock adopts either a highly ordered marching state where the flock moves at a higher mean speed (ranging from 0.5 through 1.5msec -1 ) with high polarisation/low angular momentum or a grazing state with a lower mean group speed (ranging from 0.0 through 0.5msec -1 ) and a lower degree of collective order with a wider distribution of polarisation/angular momentum values. The grazing state is characterised by a pattern of expansion and contraction of","PeriodicalId":390064,"journal":{"name":"MODSIM2023, 25th International Congress on Modelling and Simulation.","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129879549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-01DOI: 10.36334/modsim.2023.sofronova
K. Sofronova, N. Raveendran
: Thousands of natural disasters affect communities around the world yearly, causing catastrophic damages and a widespread impact on society. The extent and unpredictable nature of such disasters not only have a major social impact but also affect economic outputs, availability of resources and everyday business operations. For example, recent events such as the 2023 Turkey-Syria Earthquake and the 2022 Hurricane Ian, have put a global insight into the major losses and financial and human repercussions caused by such catastrophes. Australia is not spared from being affected by a multitude of natural disasters, including bushfires, floods, and cyclones. These disasters represent an extreme risk across Australia, causing irreparable damages to the natural environment which lead to major insurance losses for Australians yearly. Families and individuals are subject to losing valuable, irreplaceable assets, such as their homes and livestock, and face difficulty in recovering and resuming with their everyday lives.
{"title":"Statistical analysis of Australian insurance losses from historical catastrophic disasters","authors":"K. Sofronova, N. Raveendran","doi":"10.36334/modsim.2023.sofronova","DOIUrl":"https://doi.org/10.36334/modsim.2023.sofronova","url":null,"abstract":": Thousands of natural disasters affect communities around the world yearly, causing catastrophic damages and a widespread impact on society. The extent and unpredictable nature of such disasters not only have a major social impact but also affect economic outputs, availability of resources and everyday business operations. For example, recent events such as the 2023 Turkey-Syria Earthquake and the 2022 Hurricane Ian, have put a global insight into the major losses and financial and human repercussions caused by such catastrophes. Australia is not spared from being affected by a multitude of natural disasters, including bushfires, floods, and cyclones. These disasters represent an extreme risk across Australia, causing irreparable damages to the natural environment which lead to major insurance losses for Australians yearly. Families and individuals are subject to losing valuable, irreplaceable assets, such as their homes and livestock, and face difficulty in recovering and resuming with their everyday lives.","PeriodicalId":390064,"journal":{"name":"MODSIM2023, 25th International Congress on Modelling and Simulation.","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128234103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-01DOI: 10.36334/modsim.2023.mana
S. Mana, T. Peterson, S. Lade, B. Croke, T. Iwanaga
: Recent studies have revealed that catchments may not always recover from drought conditions (Peterson et al., 2021). Such runoff non-recovery results in less runoff per unit rainfall under comparable catchment conditions and therefore potentially has significant implications for water resource planning. Given that the ACT water is sourced from three main catchments (Cotter, Queanbeyan, and Murrumbidgee) it is imperative to understand if these catchments also display non-recovery and thus a finite catchment resilience to droughts. In this study, non-recovery was analysed at 18 stream gauges using linear regression between rainfall and Box-Cox transformed streamflow (Saft et al., 2015). Pre-drought, drought and post-drought periods were defined a priori and within the regression, each had a different intercept. This resulted in each period having the same slope, as shown in Figure 1. For the gauge (Cotter River at Gingera) shown in Figure 1, in the period following the millennium drought, the rainfall-runoff relationship resembles that from during the drought. This suggests that the catchment has not recovered from the drought. Figure 2 shows that out of the 18 gauges examined, 94% (n=17) present evidence of a runoff shift during droughts. Of these, 35% (n=6) show minimal recovery after the millennium drought. Examining the magnitude of the shift in the rainfall-runoff relationship (at mean annual precipitation), 56% (n=10) of the gauges show a downward shift greater than 14.6 mm/year of runoff. All the gauges observed in the Queanbeyan and Murrumbidgee Rivers and five gauges in the Cotter River exhibit signs of non-recovery (Figure 2). Overall, these findings suggest that the ACT water supply catchments do experience shifts and non-recovery in their rainfall-runoff relationships. Future
最近的研究表明，集水区可能并不总能从干旱条件中恢复(Peterson等人，2021)。在类似的集水区条件下，这种径流不恢复导致单位降雨径流较少，因此可能对水资源规划产生重大影响。考虑到澳大利亚首都地区的水来自三个主要集水区(Cotter、Queanbeyan和Murrumbidgee)，有必要了解这些集水区是否也表现出不可恢复性，因此对干旱的恢复能力有限。在本研究中，使用降雨量与Box-Cox转换后的流量之间的线性回归分析了18个流量计的不恢复情况(Saft et al.， 2015)。干旱前、干旱和干旱后时期是先验定义的，在回归中，每个时期都有不同的截距。这导致每个周期具有相同的斜率，如图1所示。对于图1所示的测量(Gingera的Cotter河)，在千年干旱之后的一段时间里，降雨量与径流的关系与干旱期间相似。这表明该流域还没有从干旱中恢复过来。图2显示，在检查的18个仪表中，94% (n=17)提供了干旱期间径流转移的证据。其中，35% (n=6)在千年干旱后显示出最小的恢复。考察降雨-径流关系的变化幅度(以年平均降水量为单位)，56% (n=10)的测量仪显示，径流的下降幅度大于14.6毫米/年。在Queanbeyan和Murrumbidgee河中观察到的所有仪表以及在Cotter河中的五个仪表都显示出不恢复的迹象(图2)。总的来说，这些发现表明ACT供水集水区在其降雨-径流关系中确实经历了变化和不恢复。未来
{"title":"Runoff non-recovery of ACT water catchments","authors":"S. Mana, T. Peterson, S. Lade, B. Croke, T. Iwanaga","doi":"10.36334/modsim.2023.mana","DOIUrl":"https://doi.org/10.36334/modsim.2023.mana","url":null,"abstract":": Recent studies have revealed that catchments may not always recover from drought conditions (Peterson et al., 2021). Such runoff non-recovery results in less runoff per unit rainfall under comparable catchment conditions and therefore potentially has significant implications for water resource planning. Given that the ACT water is sourced from three main catchments (Cotter, Queanbeyan, and Murrumbidgee) it is imperative to understand if these catchments also display non-recovery and thus a finite catchment resilience to droughts. In this study, non-recovery was analysed at 18 stream gauges using linear regression between rainfall and Box-Cox transformed streamflow (Saft et al., 2015). Pre-drought, drought and post-drought periods were defined a priori and within the regression, each had a different intercept. This resulted in each period having the same slope, as shown in Figure 1. For the gauge (Cotter River at Gingera) shown in Figure 1, in the period following the millennium drought, the rainfall-runoff relationship resembles that from during the drought. This suggests that the catchment has not recovered from the drought. Figure 2 shows that out of the 18 gauges examined, 94% (n=17) present evidence of a runoff shift during droughts. Of these, 35% (n=6) show minimal recovery after the millennium drought. Examining the magnitude of the shift in the rainfall-runoff relationship (at mean annual precipitation), 56% (n=10) of the gauges show a downward shift greater than 14.6 mm/year of runoff. All the gauges observed in the Queanbeyan and Murrumbidgee Rivers and five gauges in the Cotter River exhibit signs of non-recovery (Figure 2). Overall, these findings suggest that the ACT water supply catchments do experience shifts and non-recovery in their rainfall-runoff relationships. Future","PeriodicalId":390064,"journal":{"name":"MODSIM2023, 25th International Congress on Modelling and Simulation.","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128692687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-01DOI: 10.36334/modsim.2023.chen174
Yu-Heng Chen, Chia‐Lin Chang
: Taiwan’s information and electronics industry is a major player in global markets. Its traditional original equipment manufacturer (OEM) capability is one of its key competitive advantages. While previous studies have shown that brand building has a positive impact on performance, the government has recently encouraged the industry to conduct independent research and development and promote proprietary brands in the face of global competition and pressure for industrial upgrading. This study aimed to compare the performance of Taiwanese information and electronics firms that invest in brands with traditional OEMs, using counterfactual decomposition regression analysis to decompose firm performance into “return effects” and “covariate effects”. The results showed that firms investing in brand strategies outperformed traditional OEMs, with the performance gap between firms widening as the degree of brand strategy increased. Furthermore, the difference in performance was mainly due to the “covariate effect”, with companies with brand strategies being more willing to invest in resources such as research and development, technology acquisition and marketing in order to create a virtual circle of brand building and improve company performance. On the other hand, investing only in brand image building without developing a brand strategy has a diminishing effect on performance improvement as total output increases. In summary, this study found that investing in brand strategies is essential for Taiwanese information and electronics firms to outperform traditional OEMs. The government can use the results of this study to assess the need to promote brand strategy as a means of improving industrial performance during the process of industrial upgrading. In this way, the industry can maintain its competitive advantage and continue to play an influential role in global markets.
{"title":"Brand strategies and firm performance: A comparison of Taiwanese information and electronics firms with traditional OEMs","authors":"Yu-Heng Chen, Chia‐Lin Chang","doi":"10.36334/modsim.2023.chen174","DOIUrl":"https://doi.org/10.36334/modsim.2023.chen174","url":null,"abstract":": Taiwan’s information and electronics industry is a major player in global markets. Its traditional original equipment manufacturer (OEM) capability is one of its key competitive advantages. While previous studies have shown that brand building has a positive impact on performance, the government has recently encouraged the industry to conduct independent research and development and promote proprietary brands in the face of global competition and pressure for industrial upgrading. This study aimed to compare the performance of Taiwanese information and electronics firms that invest in brands with traditional OEMs, using counterfactual decomposition regression analysis to decompose firm performance into “return effects” and “covariate effects”. The results showed that firms investing in brand strategies outperformed traditional OEMs, with the performance gap between firms widening as the degree of brand strategy increased. Furthermore, the difference in performance was mainly due to the “covariate effect”, with companies with brand strategies being more willing to invest in resources such as research and development, technology acquisition and marketing in order to create a virtual circle of brand building and improve company performance. On the other hand, investing only in brand image building without developing a brand strategy has a diminishing effect on performance improvement as total output increases. In summary, this study found that investing in brand strategies is essential for Taiwanese information and electronics firms to outperform traditional OEMs. The government can use the results of this study to assess the need to promote brand strategy as a means of improving industrial performance during the process of industrial upgrading. In this way, the industry can maintain its competitive advantage and continue to play an influential role in global markets.","PeriodicalId":390064,"journal":{"name":"MODSIM2023, 25th International Congress on Modelling and Simulation.","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128652335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-01DOI: 10.36334/modsim.2023.devanand483
A. Devanand, M. Leonard, S. Westra, D. Nguyen
: The NSW Department of Planning and Environment (DPE) is undertaking a risk-based methodology to account for climate variability and change in developing its regional water strategies. As part of this process, historical biases and future changes associated with 6 model variants from NARCliM1.5 simulations have been analysed. This paper presents results for two future time windows centered on 2030 and 2070, for scenarios RCP 4.5 and RCP 8.5 for the southern basin region (which includes the Murrumbidgee, Murray and Snowy catchments as well as regions of Victoria and South Australia), focusing on the hydrologically relevant attributes of precipitation. The evaluation of NARCliM1.5 has been made for model ensemble averages with respect to gauged data in the southern basin for two cases, (1) GCM runs forced with historical greenhouse gas forcings (‘historical runs’) over the period 1951 to 2005, and (2) reanalysis runs (‘evaluation runs’) for the period 1979-2013. The NARCliM1.5 projections were analysed for two 30-year time windows centered on 2030 and 2070 respectively. The range of grid level future changes projected by the NARCliM1.5 ensemble mean are not outside the ranges projected by other sources of climate projections.
{"title":"NARCliM1.5 projections over the southern Murray�Darling Basin, Australia","authors":"A. Devanand, M. Leonard, S. Westra, D. Nguyen","doi":"10.36334/modsim.2023.devanand483","DOIUrl":"https://doi.org/10.36334/modsim.2023.devanand483","url":null,"abstract":": The NSW Department of Planning and Environment (DPE) is undertaking a risk-based methodology to account for climate variability and change in developing its regional water strategies. As part of this process, historical biases and future changes associated with 6 model variants from NARCliM1.5 simulations have been analysed. This paper presents results for two future time windows centered on 2030 and 2070, for scenarios RCP 4.5 and RCP 8.5 for the southern basin region (which includes the Murrumbidgee, Murray and Snowy catchments as well as regions of Victoria and South Australia), focusing on the hydrologically relevant attributes of precipitation. The evaluation of NARCliM1.5 has been made for model ensemble averages with respect to gauged data in the southern basin for two cases, (1) GCM runs forced with historical greenhouse gas forcings (‘historical runs’) over the period 1951 to 2005, and (2) reanalysis runs (‘evaluation runs’) for the period 1979-2013. The NARCliM1.5 projections were analysed for two 30-year time windows centered on 2030 and 2070 respectively. The range of grid level future changes projected by the NARCliM1.5 ensemble mean are not outside the ranges projected by other sources of climate projections.","PeriodicalId":390064,"journal":{"name":"MODSIM2023, 25th International Congress on Modelling and Simulation.","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128986729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-01DOI: 10.36334/modsim.2023.hassan
A. Hassan, G. Accary, Duncan S Sutherland, K. Moinuddin
: A junction fire is the intersection of two fire fronts in a wildfire whose impact can be devastating. The rate of spread (ROS) of the junction point and the fire intensity can be intensified by slope and wind. The study of a junction fire using physics-based simulation tools aims to give an interpretation of the behaviour by examining the key factors that influence the fires, namely junction angle, slope and wind. In this research, at first, the physics-based model FIRESTAR3D was validated against a set of laboratory-scale junction fire experiments conducted with a shrub fuel bed. A grid resolution and domain size sensitivity study was carried out. Then numerical simulations of laboratory-scale junction fires were conducted using FIRESTAR3D under various junction angles (15° to 90°), on different slopes (0° to 40°) and with and without unidirectional wind conditions. Simulations were carried out under low and intermediate driving wind speeds (maximum 4 m/s). Fig. 1 represents the computational domain and an example of fire perimeter evolution showing the deceleration in the junction point advancement for non-slope cases.
{"title":"Physics-based modelling of junction fires: Effects of some topographical parameters in intersecting fires","authors":"A. Hassan, G. Accary, Duncan S Sutherland, K. Moinuddin","doi":"10.36334/modsim.2023.hassan","DOIUrl":"https://doi.org/10.36334/modsim.2023.hassan","url":null,"abstract":": A junction fire is the intersection of two fire fronts in a wildfire whose impact can be devastating. The rate of spread (ROS) of the junction point and the fire intensity can be intensified by slope and wind. The study of a junction fire using physics-based simulation tools aims to give an interpretation of the behaviour by examining the key factors that influence the fires, namely junction angle, slope and wind. In this research, at first, the physics-based model FIRESTAR3D was validated against a set of laboratory-scale junction fire experiments conducted with a shrub fuel bed. A grid resolution and domain size sensitivity study was carried out. Then numerical simulations of laboratory-scale junction fires were conducted using FIRESTAR3D under various junction angles (15° to 90°), on different slopes (0° to 40°) and with and without unidirectional wind conditions. Simulations were carried out under low and intermediate driving wind speeds (maximum 4 m/s). Fig. 1 represents the computational domain and an example of fire perimeter evolution showing the deceleration in the junction point advancement for non-slope cases.","PeriodicalId":390064,"journal":{"name":"MODSIM2023, 25th International Congress on Modelling and Simulation.","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129432215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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