Infrastructure Engineering - Research Publications

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    A predictive model for spatio-temporal variability in stream water quality
    Guo, D ; Lintern, A ; Webb, JA ; Ryu, D ; Bende-Michl, U ; Liu, S ; Western, AW ( 2019-07-23)
    Abstract. Degraded water quality in rivers and streams can have large economic, societal and ecological impacts. Stream water quality can be highly variable both over space and time. To develop effective management strategies for riverine water quality, it is critical to be able to predict these spatio-temporal variabilities. However, our current capacity to model stream water quality is limited, particularly at large spatial scales across multiple catchments. This is due to a lack of understanding of the key controls that drive spatio-temporal variabilities of stream water quality. To address this, we developed a Bayesian hierarchical statistical model to analyse the spatio-temporal variability in stream water quality across the state of Victoria, Australia. The model was developed based on monthly water quality monitoring data collected at 102 sites over 21 years. The modelling focused on six key water quality constituents: total suspended solids (TSS), total phosphorus (TP), filterable reactive phosphorus (FRP), total Kjeldahl nitrogen (TKN), nitrate-nitrite (NOx), and electrical conductivity (EC). Among the six constituents, the models explained varying proportions of variation in water quality. EC was the most predictable constituent (88.6 % variability explained) and FRP had the lowest predictive performance (19.9 % variability explained). The models were validated for multiple sets of calibration/validation sites and showed robust performance. Temporal validation revealed a systematic change in the TSS model performance across most catchments since an extended drought period in the study region, highlighting potential shifts in TSS dynamics over the drought. Further improvements in model performance need to focus on: (1) alternative statistical model structures to improve fitting for the low concentration data, especially records below the detection limit; and (2) better representation of non-conservative constituents by accounting for important biogeochemical processes. We also recommend future improvements in water quality monitoring programs which can potentially enhance the model capacity, via: (1) improving the monitoring and assimilation of high-frequency water quality data; and (2) improving the availability of data to capture land use and management changes over time.
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    Comparisons of cancer-associated fibroblasts in the intratumoral stroma and invasive front in colorectal cancer.
    Son, GM ; Kwon, M-S ; Shin, D-H ; Shin, N ; Ryu, D ; Kang, C-D (Ovid Technologies (Wolters Kluwer Health), 2019-05)
    The aim of this study was to evaluate the cytomorphologic maturity and molecular activation of cancer-associated fibroblasts (CAFs) in the intratumoral stroma and invasive front in colorectal cancer and understand how they affect cancer invasion and long-term oncological outcomes.The cytomorphologic maturity of and α-smooth muscle actin (α-SMA), fibroblast activation protein α (FAPα), and fibroblast-specific protein 1 (FSP-1) expression in CAFs in the intratumoral stroma (CAF) and the invasive front (CAF) of colorectal cancer tissues were compared (n = 147). The correlations between CAF maturation, molecular activity markers, and cancer invasion were evaluated by network analysis. Overall survival and systemic recurrence were analyzed to assess the oncological effects of CAF properties.The cytomorphologic maturation rate was comparable between CAF and CAF. The presence of mature CAFs was related to epidermal growth factor receptor overexpression in cancer cells. Expression rates of α-SMA (96.6%-98.0%) and FAPα (18.6%-22.9%) were similar between CAF and CAF. FSP-1 expression was more frequent in CAF than in CAF (66.4% vs 58.2%, P = .038). There was a significant decrease in FSP-1 expression in CAF and CAF in higher stages. The infiltrating growth pattern of the tumor was more frequent in the immature CAF. In colorectal cancer with perineural invasion and lymph node metastasis, FSP-1 expression in CAF was significantly lower. On multivariate analysis using the Cox proportional hazards model, immature CAF was found to be an independent prognostic factor of overall survival. In non-metastatic (stage I-III) colorectal cancer patients, CAF maturity was not a prognostic factor for systemic recurrence.Cytomorphologic maturity and molecular activation markers were similar between CAFs in the intratumoral stroma and invasive front of colorectal cancer.
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    Cancer-Associated Fibroblasts and Desmoplastic Reactions Related to Cancer Invasiveness in Patients With Colorectal Cancer.
    Shin, N ; Son, GM ; Shin, D-H ; Kwon, M-S ; Park, B-S ; Kim, H-S ; Ryu, D ; Kang, C-D (Korean Society of Coloproctology, 2019-02)
    PURPOSE: We evaluated the relationship of cancer-associated fibroblasts (CAFs) and desmoplastic reactions with cancer invasiveness and long-term outcomes in patients with colorectal cancer (CRC). METHODS: Histologic evaluation of mature CAFs and desmoplasia was performed by observing the collagen fiber structure and fibroblast cytomorphology in the intratumoral stroma and invasive front of CRC tissues. Cancer-cell invasiveness was evaluated using lymphatic invasion, vascular invasion, perineural invasion, tumor budding, and tumor growth patterns. Overall survival and systemic recurrence were analyzed. A network analysis was performed between CAF maturation, desmoplastic reaction, and cancer invasiveness. RESULTS: The proportions of mature CAFs in the intratumoral stroma and the invasive front were 57.6% and 60.3%, respectively. Epidermal growth factor receptor (EGFR) overexpression was significantly higher in the mature CAFs in the invasive front as compared to immature CAFs. Lymphatic invasion increased as the number of mature fibroblasts in the intratumoral stroma increased. Tumor budding was observed in almost half of both mature and immature stroma samples and occurred more frequently in infiltrating tumors. On network analysis, well-connected islands were identified that was associated with EGFR overexpression, CAF maturation, and infiltrating tumor growth patterns leading to tumor budding. CONCLUSION: The maturity of CAFs and desmoplastic reactions were associated with cancer invasion. However, the cytomorphologic characteristics of CAFs were insufficient as an independent prognostic factor for patients with CRC.
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    Justin Costelloe: a champion of arid-zone water research
    Western, AW ; Matic, V ; Peel, MC (Springer Verlag, 2019-11-06)
    Justin Francis Costelloe (Fig. 1) was born in 1965. He grew up in the mining city of Bendigo (Victoria, Australia) before studying Earth Sciences at the University of Melbourne. He went on to work as an exploration geologist in the mining industry in the dryland regions of Australia and Chile. He developed a love of Australia’s desert landscapes and returned to undertake Masters and PhD studies on arid zone hydrology at the University of Melbourne, before continuing as a research fellow and senior research fellow leading arid zone research projects. Justin was a leader in research aimed at understanding surface water and groundwater in Australia’s arid zone and also made important interdisciplinary contributions linking the hydrology and ecology of the arid zone, with a focus on Australia’s iconic Channel Country and the Great Artesian Basin (GAB).
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    High strength/density ratio in a syntactic foam made from one-part mix geopolymer and cenospheres
    Hajimohammadi, A ; Ngo, T ; Provis, JL ; Kim, T ; Vongsvivut, J (Elsevier Ltd, 2019-09-15)
    By designing a composite of one-part mix geopolymer and hollow cenospheres, a commercially viable and environmentally-friendly foam was synthesised with a high strength/density ratio. The composite is made of a dry mix powder of geopolymer source materials, sodium silicate alkali activator and cenospheres, which starts to react when mixed with water. As the geopolymer reacts and gains strength over time, the surface of the cenospheres takes part in the reaction and forms a strong bond with the binding matrix. Synchrotron-based Fourier transform infrared microspectroscopy revealed, for the first time, the chemical bonding interaction of the amorphous interfacial layer between the geopolymer and cenospheres. The resulting foam composite gained a strength of 17.5 MPa at a density of 978 kg/m3, which is noticeably higher than that of existing environmentally-friendly lightweight foams made under ambient conditions. The thermal conductivity of the foam was measured to be around 0.28 kW/mK, which is similar to that of foam concrete. This foam produced in this study is found to be lightweight, strong and possess a desirable insulating capacity, while the preparation process of the one-part mix composite is maintained simply by adding water and curing the mixture at an ambient temperature.
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    Vibration of cracked functionally graded microplates by the strain gradient theory and extended isogeometric analysis
    Nguyen, HX ; Atroshchenko, E ; Tuan, N ; Nguyen-Xuan, H ; Vo, TP (ELSEVIER SCI LTD, 2019-05-15)
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    The Feasibility of a BIM-Driven Approach to Support Building Subdivision Workflows-Case Study of Victoria, Australia
    Olfat, H ; Atazadeh, B ; Shojaei, D ; Rajabifard, A (MDPI, 2019-11)
    Cities are facing dramatic challenges due to population growth and the massive development of high-rises and complex structures, both above and below the ground surface. Decision-makers require access to an efficient land and property information system, which is digital, three-dimensional (3D), spatially accurate, and dynamic containing interests in land (rights, restrictions and responsibilities—RRRs) to manage the legal and physical complexities of urban environments. However, at present, building subdivision workflows only support the two-dimensional (2D) building subdivision plans in PDF or image formats. These workflows result in a number of issues, such as the plan preparation being complex, the examination process being labor intensive and requiring technical expertise, information not being easily reusable by all subdivision stakeholders, queries, analyses, and decision-making being inefficient, and the RRRs interpretation being difficult. The aim of this research is to explore the potential of using Building Information Modelling (BIM) and its open standards to support the building subdivision workflows. The research that is presented in this paper proposes a BIM-driven building subdivision workflow, evaluated through a case study in the state of Victoria, Australia. The results of the study confirmed that the proposed workflow could provide a feasible integrated mechanism for stakeholders to share, document, visualize, analyze, interpret, and reuse 3D digital cadastral data over the lifespan of a building subdivision project.
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    Equifinality and Flux Mapping: A New Approach to Model Evaluation and Process Representation Under Uncertainty
    Khatami, S ; Peel, MC ; Peterson, TJ ; Western, AW (AMER GEOPHYSICAL UNION, 2019-11)
    Abstract Uncertainty analysis is an integral part of any scientific modeling, particularly within the domain of hydrological sciences given the various types and sources of uncertainty. At the center of uncertainty rests the concept of equifinality, that is, reaching a given endpoint (finality) through different pathways. The operational definition of equifinality in hydrological modeling is that various model structures and/or parameter sets (i.e., equal pathways) are equally capable of reproducing a similar (not necessarily identical) hydrological outcome (i.e., finality). Here we argue that there is more to model equifinality than model structures/parameters, that is, other model components can give rise to model equifinality and/or could be used to explore equifinality within model space. We identified six facets of model equifinality, namely, model structure, parameters, performance metrics, initial and boundary conditions, inputs, and internal fluxes. Focusing on model internal fluxes, we developed a methodology called flux mapping that has fundamental implications in understanding and evaluating model process representation within the paradigm of multiple working hypotheses. To illustrate this, we examine the equifinality of runoff fluxes of a conceptual rainfall‐runoff model for a number of different Australian catchments. We demonstrate how flux maps can give new insights into the model behavior that cannot be captured by conventional model evaluation methods. We discuss the advantages of flux space, as a subspace of the model space not usually examined, over parameter space. We further discuss the utility of flux mapping in hypothesis generation and testing, extendable to any field of scientific modeling of open complex systems under uncertainty.
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    Joint Estimation of Gross Recharge, Groundwater Usage, and Hydraulic Properties within HydroSight
    Peterson, TJ ; Fulton, S (Wiley, 2019-11-01)
    Groundwater management decisions are often founded upon estimates of aquifer hydraulic properties, recharge and the rate of groundwater usage. Too often hydraulic properties are unavailable, recharge estimates are very uncertain, and usage is unmetered or infrequently metered over only recent years or estimated using numerical groundwater models decoupled from the drivers of drawdown. This paper extends the HydroSight groundwater time‐series package ( http://peterson‐tim‐j.github.io/HydroSight/) to allow the joint estimation of gross recharge, transmissivity, storativity, and daily usage at multiple production bores. A genetic evolutionary scheme was extended from estimating time‐series model parameters to also estimating time series of usage that honor metered volumes at each production bore and produces (1) the best fit with the observed hydrograph and (2) plausible estimates of actual evapotranspiration and hence recharge. The reliability of the approach was rigorously tested. Repeated calibration of models for four bores produced estimates of transmissivity, storativity, and mean recharge that varied by a factor of 0.22‐0.32, 0.13‐0.2, and 0.03‐0.48, respectively, when recharge boundary effects were low and the error in monthly, quarterly, and biannual metered usage was generally <10%. Application to the 30 observation bores within the Warrion groundwater management area (Australia), produced a coefficient of efficiency of ≥0.80 at 22 bores and ≥0.90 at 12 bores. The aquifer transmissivity and storativity were reasonably estimated, and were consistent with independent estimates, while mean gross recharge may be slightly overestimated. Overall, the approach allows greater insights from the available data and provides opportunity for the exploration of usage and climatic scenarios.
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    The role of floods and droughts on riverine ecosystems under a changing climate
    Parasiewicz, P ; King, EL ; Webb, JA ; Piniewski, M ; Comoglio, C ; Wolter, C ; Buijse, AD ; Bjerklie, D ; Vezza, P ; Melcher, A ; Suska, K (Wiley, 2019-12-01)
    Floods and droughts are key driving forces shaping aquatic ecosystems. Climate change may alter key attributes of these events and consequently health and distribution of aquatic species. Improved knowledge of biological responses to different types of floods and droughts in rivers should allow the better prediction of the ecological consequences of climate change‐induced flow alterations. This review highlights that in unmodified ecosystems, the intensity and direction of biological impacts of floods and droughts vary, but the overall consequence is an increase in biological diversity and ecosystem health. To predict the impact of climate change, metrics that allow the quantitative linking of physical disturbance attributes to the directions and intensities of biological impacts are needed. The link between habitat change and the character of biological response is provided by the frequency of occurrence of the river wave characteristic—that is the event's predictability. The severity of impacts of floods is largely related to the river wave amplitude (flood magnitude), while the impact of droughts is related to river wavelength (drought duration).