Infrastructure Engineering - Research Publications
Permanent URI for this collection
Search Results
1 - 10 of 551
-
ItemPlant Macrofossils Reveal Aquatic Macrophyte Successions of a Typical Shallow Lake (Huanggai Lake, China) in the Past Century(MDPI, 2022-06-01)Aquatic macrophytes are one of the important biotic components of shallow lake ecosystems. Understanding the long-term evolution of the macrophyte community is crucial for lake management. Huanggai Lake, a typical shallow lake in the middle reach of the Yangtze River, was selected as the research site for this study. Based on 210Pb/137Cs dating, aquatic plant macrofossils were used to reconstruct the succession of aquatic macrophytes in the past century. Our results show that the lake maintained a consistent natural state before 1940, with a relatively low abundance of aquatic plants dominated by species such as Najas minor. From 1940 to 1974, human activities gradually intensified in the lake leading to the emergence of eutrophic species such as Potamogeton maackianus, along with the increasing abundance of other emergent and floating aquatic macrophytes. Since 1974, more pollution-resistant, emergent species such as Potamogeton maackianus and Potamogeton crispus have become dominant. The abundance of aquatic macrophytes reached its maximum in the early 1990s. Combined with macrofossil succession and other multiple sedimentary proxy analyses, driving mechanisms for aquatic macrophytes are discussed. Both the nearby Liangzi Lake and Huanggai Lake share many common features of aquatic plant evolution. This study is the first of its kind to use plant macrofossils (with identifiable images) as a proxy for aquatic macrophyte succession in a shallow Yangtze lake. In absence of long-term monitoring records, this study highlights the increased application of plant macrofossils for reconstructing the vegetation dynamics and restoration of degraded lakes exposed to severe anthropogenic impacts over the past century.
-
ItemFramework for standardising carbon neutrality in building projects(Elsevier, 2022-11-01)The construction industry accounts for approximately 40% of the global carbon emissions and is the largest consumer of materials and energy. Given the Paris Agreement target towards global net-zero greenhouse gas (GHG) emissions, significant changes are required in the design, construction and use of buildings. This study applies a qualitative approach that combines a systematic literature review (SLR) with in-depth semi-structured interviews with experts to analyse existing carbon neutrality frameworks and decision support tools; expanding current knowledge by bringing to the fore the challenges experienced in implementing these frameworks. This research effort reveals an inadequacy in frameworks for effective decision-making on decarbonisation strategies along the project lifecycle. A novel framework that breaks down the activities and decision points across the entire project lifecycle is proposed to bridge this gap in literature. The developed framework defines whole lifecycle cost, whole lifecycle energy use, exergetic lifecycle and whole lifecycle emissions as the four critical underpinning variables considered in making decarbonisation decisions. It further details the key evaluation criteria to facilitate decision-making at each stage of the project lifecycle and provides decision-makers with contextual guidance for assessing the impact of their decarbonisation decisions at the planning, delivery, closure and operations phases of the project. It will assist academic researchers, building owners and industry professionals to keep track of the project's carbon neutrality target and encourage best practices for carbon emission reduction in the building sector.
-
ItemIndentation into an aluminium panel by the impact of a rigid spherical object(Elsevier BV, 2022-11)This paper introduces algebraic expressions for determining the amount of permanent indentation caused to an aluminium panel when impacted by a rigid spherical object. The magnitude of indentation is observed to vary significantly with the position of impact within the panel when the impactor and the velocity of impact are kept the same. This spatial variation of indentation is caused by the changes in the combinational mass (which is in turn function of the participating mass of the plate) and the Coefficient of Restitution COR. Both parameters are shown to correlate with the position of impact. The proposed algebraic expression featuring the combinational mass and COR as input parameters, allows potential damage to the panel to be predicted conveniently in day-to-day engineering practices. The original contribution of this article is in illustrating this phenomenon analytically, and have the analytical predictions verified by impact experimentation which has been conducted by the authors on panels of varying dimensions.
-
ItemTranslating Place-Related Questions to GeoSPARQL Queries(ACM, 2022-04-25)Many place-related questions can only be answered by complex spatial reasoning, a task poorly supported by factoid question retrieval. Such reasoning using combinations of spatial and non-spatial criteria pertinent to place-related questions is increasingly possible on linked data knowledge bases. Yet, to enable question answering based on linked knowledge bases, natural language questions must first be re-formulated as formal queries. Here, we first present an enhanced version of YAGO2geo, the geospatially-enabled variant of the YAGO2 knowledge base, by linking and adding more than one million places from OpenStreetMap data to YAGO2. We then propose a novel approach to translate the place-related questions into logical representations, theoretically grounded in the core concepts of spatial information. Next, we use a dynamic template-based approach to generate fully executable GeoSPARQL queries from the logical representations. We test our approach using the Geospatial Gold Standard dataset and report substantial improvements over existing methods.
-
ItemBias-Bounded Estimation of AmbiguiTy: A Method for Radio Interferometric Positioning(IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2022-01-01)Carrier phase signals form the basis of various interferometric measurement models and estimation techniques that have parameters of which some are integer. In this paper, integer least-squares estimation theory is extended and applied to bias-bounded mixed-integer models. This extension accommodates the presence of bounded real-valued parameters in mixed-integer models through incorporating prior knowledge of a set, in which the parameters reside, into the estimation process. This enables one to jointly estimate the ambiguous phase cycles and the parameters of interest. To compute such mixed-integer estimates, a fast search strategy is developed that makes use of a dual-ellipsoid encompassing region. The volume of the stated region is quantified and its links to existing ellipsoidal search spaces are highlighted. Simulated and real-world data are employed to illustrate the theory. It is then, for the first time, shown that the proposed method makes single-epoch, phase-only positioning feasible with Global Navigation Satellite Systems (GNSS).
-
ItemA review of augmented reality visualization methods for subsurface utilities(Elsevier BV, 2022-01-01)Subsurface utilities are important assets that need to be perceived during any construction activities. Positioning and visualizing the subsurface utilities before the construction work starts has significant benefits for the effective management of construction projects. Augmented Reality (AR) is a promising technology for the visualization of subsurface utilities. The aim of this paper is to provide a comprehensive review of the state-of-the-art in AR visualization of subsurface utilities, including existing AR visualization methods, categorization of the methods and their drawbacks, comprehensive discussion on the challenges, research gaps and potential solutions. The paper begins with an introduction of current practice of locating subsurface utilities and an overview of different reality technologies including AR. We propose a taxonomy of AR visualization methods including X-Ray view, transparent view, shadow view, topo view, image rendering and cross-section view. We provide a comparison of existing methods in terms of quality of depth perception, occlusion of real world, complexity of visualization and parallax effect followed by a discussion of the drawbacks in these methods. Poor depth perception, parallax effect caused by the user movement, poor positional accuracy in Global Navigation Satellite System (GNSS) deprived or indoor areas and unavailability of accurate location information for generating virtual models are identified as main challenges and topics of future research in effective AR visualization of subsurface utilities.
-
ItemCorrigendum to “A review of augmented reality visualization methods for subsurface utilities” [Adv. Eng. Inf. 51 (2022) 101498] (Advanced Engineering Informatics (2022) 51, (S1474034621002470), (10.1016/j.aei.2021.101498))(Elsevier BV, 2022-01-01)The authors regret, Our article that was published in the previous issue of the journal contains incorrect citations to research work in a few places. The correct reference should be 140. Hansen, L.H.; Fleck, P.; Stranner, M.; Schmalstieg, D.; Arth, C. Augmented Reality for Subsurface Utility Engineering, Revisited. IEEE Transactions on Visualization and Computer Graphics 2021, 27, 4119–4128. Instead of 140. Piroozfar, P.; Judd, A.; Boseley, S.; Essa, A.; Farr, E.R. Augmented reality for urban utility infrastructure: a UK perspective. In Collaboration and Integration in Construction, Engineering, Management and Technology; Springer: 2021; pp. 535–541. Additionally, Figure 20 should be referenced as 37. Eren, M.T.; Balcisoy, S. Evaluation of X-ray visualization techniques for vertical depth judgments in underground exploration. The visual Computer 2017, 34, 405–416, https://doi.org/10.1007/s00371-016-1346-5. Instead of 62. Doolani, S.; Wessels, C.; Kanal, V.; Sevastopoulos, C.; Jaiswal, A.; Nambiappan, H.; Makedon, F. A Review of Extended Reality (XR) Technologies for Manufacturing Training. Technologies 2020, 8, https://doi.org/10.3390/technologies8040077. And Figure 21 should be referenced as 144. Baek, J.-M.; Hong, I.-S. The Design of an Automatically Generated System for Cross Sections of Underground Utilities using Augmented Reality. International Journal of Smart Home 2013, 7, 255–264, https://doi.org/10.14257/ijsh.2013.7.6.25. Instead of 64. Chuah, S.H.-W. Why and who will adopt extended reality technology? Literature review, synthesis, and future research agenda. Literature Review, Synthesis, and Future Research Agenda (December 13, 2018) 2018. The authors would like to apologise for any inconvenience caused.
-
ItemRequirements of a data storage infrastructure for effective land administration systems: case study of Victoria, Australia(TAYLOR & FRANCIS LTD, 2022-01-27)Land administration systems are being modernised to streamline the cadastral data lodgement. However, in many jurisdictions, cadastral data are still stored as a flat file. This method of data storage has significant limitations in terms of effective access, management, query, and analysis of cadastral data. Therefore, this study elicited the requirements and proposed an approach to automate the cadastral data storage. The proposed approach was successfully implemented within the land registry organisation in Victoria, Australia and the database management system was rigorously tested. The outcomes can potentially contribute to the implementation of a similar data storage infrastructure in other jurisdictions.
-
ItemPlate anchor capacity estimation through CPT tip resistance in sand(Taylor and Francis group, 2022-06-15)Reliable estimation of plate anchor uplift capacity in sand through analytical and empirical equations is often complicated due to uncertainties in estimation of soil properties required in the equations. In order to address this uncertainty, this study proposes a correlation to estimate plate anchor vertical uplift capacity in sand based on cone tip resistance measured from cone penetrometer tests (CPT). The correlation was established using a database of reported centrifuge experiments on circular, rectangular and strip anchors in loose and dense silica sand at various embedment depths and g-levels, along with the corresponding centrifuge CPTs performed in the same testing boxes. The centrifuge cone tip resistances were also depth-corrected to remove the effect of shallow embedment. Through regression analyses, the correlation between plate anchor capacity and cone tip resistance in dimensionless form was developed, with different coefficients fitted for circular, rectangular and strip anchors respectively.
-
ItemAn enhanced J-integral for hydraulic fracture mechanics(Wiley, 2022-08-01)This article revisits the formulation of the J-integral in the context of hydraulic fracture mechanics. We demonstrate that the use of the classical J-integral in finite element models overestimates the length of hydraulic fractures in the viscosity-dominated regime of propagation. A finite element analysis shows that the inaccurate numerical solution for fluid pressure is responsible for the loss in accuracy of the J-integral. With this understanding, two novel contributions are presented. The first contribution consists of two variations of the J-integral, termed the (Formula presented.) and (Formula presented.) -integral, that demonstrate an enhanced ability to predict viscosity-dominated propagation. In particular, such (Formula presented.) -integrals accurately extract stress intensity factors in both viscosity and toughness-dominated regimes of propagation. The second contribution consists of a methodology to extract the propagation velocity from the energy release rate applicable throughout the toughness-viscous propagation regimes. Both techniques are combined to form an implicit front-tracking (Formula presented.) -algorithm capable of quickly converging on the location of the fracture front independently to the toughness-viscous regime of propagation. The (Formula presented.) -algorithm represents an energy-based alternative to the aperture-based methods frequently used with the Implicit Level Set Algorithm to simulate hydraulic fracturing. Simulations conducted at various resolutions of the fracture suggest that the new approach is suitable for hydro-mechanical finite element simulations at the reservoir scale.