Infrastructure Engineering - Research Publications
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ItemMultiple stable states in hydrological models: An ecohydrological investigation(American Geophysical Union, 2009-03-07)Many physical-based models of surface and groundwater hydrology are constructed without the possibility of multiple stable states for the same parameter set. For such a conceptualization, at the cessation of a transient hydrological disturbance of any magnitude the model will return to the same stable state and thus show an infinite resilience. To highlight and falsify this assumption, a numerical distributed ecohydrological model (coupled hillslope Boussinesq-vertically lumped vadose zone) is presented, in which qualitatively different steady state water table elevations exist for the same parameter set. The multiple steady states are shown to emerge from a positive feedback arising from a reduction in leaf area index (LAI) and thus transpiration, as a saline water table approaches the surface. Limit cycle continuation is also undertaken to quantify the state-space location of the threshold (repellor) between the steady states (attractors) and quantify the resilience. While the model is biophysically simple, it is sufficiently complex to challenge this potentially significant assumption within water resource planning.
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ItemOptimization of a similarity measure for estimating ungauged streamflow(AMER GEOPHYSICAL UNION, 2009-10-17)One approach to predicting streamflow in an ungauged catchment is to select an ensemble of hydrological models previously identified for similar gauged catchments, where the similarity is based on some combination of important physical catchment attributes. The focus of this paper is the identification of catchment attributes and optimization of a similarity measure to produce the best possible ungauged streamflow predictions given a data set and a conceptual model structure. As a case study, the SimHyd rainfall‐runoff model is applied to simulate monthly streamflow in 184 Australian catchments. Initial results show that none of 27 catchment attributes can be safely said to consistently give a better ensemble of models than random selection when used independently of other attributes. This is contrary to prior expectations and indicates the sparseness of information within our database of catchments, the importance in this case of prior knowledge for defining important attributes, and the potential importance of combining multiple attributes in order to usefully gauge similarity. Seven relatively independent attributes are then selected on the basis of prior knowledge. The weight with which each of these attributes contributes to the similarity measure is optimized to maximize streamflow prediction performance across a set of 95 catchments. The other 89 catchments are used to independently test the accuracy of streamflow predictions. Using the optimal set of weights led to marked improvement in the accuracy of predictions, showing that the method, while inferior to local calibration, is superior to alternative methods of model regionalization based on regression and spatial proximity. However, there is evidence of nonuniqueness in the optimal solution and the possibility that the attribute weights are somewhat dependent on the catchments used.
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ItemNo Preview AvailableThermal evaluation of a greenhouse in a remote high altitude area of Nepal(RERIC, 2009-06-01)Remote communities in the high altitude areas of Nepal suffer both chronic and acute malnutrition. This is due to a shortage of arable land and a harsh climate. For seven months of the year, the harvesting of fresh vegetables is almost impossible. Greenhouse technology, if appropriate for the location and its community, can extend the growing season considerably. Experience in the Ladakh region of India indicates that year-round cropping is possible in greenhouses in cold mountainous areas. A simple 50-m 2 greenhouse has been constructed in Simikot, the main town of Humla, northwest Nepal. This paper describes the evaluation of the thermal performance of that greenhouse. Both measurement and simulation were used in the evaluation. Measurements during the winter of 2006-7 indicate that the existing design is capable of producing adequate growing conditions for some vegetable crops, but that improvements are required if crops like tomatoes are to be grown successfully. Options to improve the thermal performance of the greenhouse have been investigated by simulation. Improvements to the building envelope such as wall insulation, double-glazing and using a thermal screen were simulated with a validated TRNSYS model. The impact of the addition of nighttime heat from internal passive solar water collectors was also predicted. The simulations indicate that the passive solar water collectors would raise the average greenhouse air temperature by 2.5°C and the overnight air temperature would increase by 4.0°C. When used in combination, overnight temperatures are predicted to by almost 7°C higher.
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ItemAnalysis of the platypus genome suggests a transposon origin for mammalian imprinting(BIOMED CENTRAL LTD, 2009)BACKGROUND: Genomic imprinting is an epigenetic phenomenon that results in monoallelic gene expression. Many hypotheses have been advanced to explain why genomic imprinting evolved in mammals, but few have examined how it arose. The host defence hypothesis suggests that imprinting evolved from existing mechanisms within the cell that act to silence foreign DNA elements that insert into the genome. However, the changes to the mammalian genome that accompanied the evolution of imprinting have been hard to define due to the absence of large scale genomic resources between all extant classes. The recent release of the platypus genome has provided the first opportunity to perform comparisons between prototherian (monotreme; which appear to lack imprinting) and therian (marsupial and eutherian; which have imprinting) mammals. RESULTS: We compared the distribution of repeat elements known to attract epigenetic silencing across the entire genome from monotremes and therian mammals, particularly focusing on the orthologous imprinted regions. There is a significant accumulation of certain repeat elements within imprinted regions of therian mammals compared to the platypus. CONCLUSIONS: Our analyses show that the platypus has significantly fewer repeats of certain classes in the regions of the genome that have become imprinted in therian mammals. The accumulation of repeats, especially long terminal repeats and DNA elements, in therian imprinted genes and gene clusters is coincident with, and may have been a potential driving force in, the development of mammalian genomic imprinting. These data provide strong support for the host defence hypothesis.
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ItemTowards e-Land administration: electronic plans of subdivisions in Victoria(Surveying and Spatial Sciences Institute, 2009)The Internet and web technologies are now thoroughly integrated into the business of the cadastre, with initiatives like VOTS, LASSI, SMES, LANDATA and SPEAR completed or well underway in Victoria. These technologies provide great opportunities for better service delivery, more customer satisfaction and reductions in operating costs through integrated electronic land administration. With this systematic introduction of the Internet and web technologies into the business of the cadastre, electronic lodgement of plans of subdivisions (ePlan) are about to introduce a new era to the surveying industry by providing an infrastructure for the digital lodgement, exchange, alteration, examination and approval of plans of subdivisions and their associated documents and data in this State. A number of components are needed to be established and a number of current systems are needed to be re-engineered through the ePlan project implementation. This article introduces the Victorian ePlan initiative and outlines the technical component of the system. The ePlan initiative will bring significant benefits to the surveying profession, land development industry, local councils, State Government agencies and instrumentalities and other key stakeholders involved in the land development process by optimising the current practices of submitting plans of subdivision in Victoria, both paper-based and PDF-based plans, by making them fully electronic. Finally, the article discusses that the electronic plan of subdivision is not an end by itself; rather it is a means that facilitates achieving a number of goals remarkably authoritative cadastral database, standardised data exchange between user and databases and electronic land development process.
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ItemAd Hoc Solution of the Multicommodity-Flow-Over-Time Problem(IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2009-12)
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ItemTechniques for efficient and effective transformed image identification(Elsevier BV, 2009-11)
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ItemFacilitating urban management through local SDI case study: the Municipality of Tehran( 2009)Integrated and sustainable management of cities is one of the most important challenges facing many countries. In this critical societal challenge context, spatial data is key for decision making, planning and management of cities. Thus, in order to have sustainable management and planning there is a need for managers and planners to have access to reliable, seamless and accurate spatial data. However, the current situation regarding availability, integration, sharing and its effective application by planners and decision makers is not very promising in many jurisdictions worldwide including Iran and Pakistan- the two countries under study by authors. Based on current situation, in urban management in Iran there is a need for an agreed platform that facilitates access to and sharing of spatially related data, services and other resources among different disciplines within any jurisdiction. This platform should also address characteristics such as standards and specifications for data collection, management, maintenance and distribution of spatial data. Having said that, in order to facilitate this situation and respond to the needs, many countries are developing Spatial Data Infrastructures (SDIs) which is a concept for facilitating and coordinating of sharing and integrating of data through different political and administrative levels. SDI can be developed at different levels ranging from local to state/provincial, national, regional and global. SDI as a platform can help to reduce the duplication and save resources in data collection which usually occur due to unknown information about availability of datasets among different urban organizations. In addition, organizations involve in urban planning can have access to a comprehensive dataset of the interested area like a city to achieve sustainable urban planning. This paper discusses the importance and benefits of developing SDI as an enabling platform for urban planning and management based on a case study, namely Tehran Municipality in Iran by exploring challenges and issues in accessing and sharing spatial data in this jurisdiction. The paper then presents and discusses the process and experiences of developing an SDI Roadmap for this municipality.
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ItemSDI for collaborative health services planning(GSDI Association, 2009)
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ItemSDI governance bridging the gap between people and geospatial resources( 2009)Organisational arrangements have long been recognised as a critical enabler and fundamental component of Spatial Data Infrastructure (SDI). More recently, the term “governance” has become increasingly used to refer to aspects of institutional frameworks that support SDI. However, given the polysemous nature of the term and the evolving nature of approaches to implementing SDI, it not clear exactly what is meant by the term “SDI governance” and thus the scope, nature and challenges of governance are not well understood. Through an exploration of concepts and model of governance in a variety of contexts, a conceptual model of SDI governance is being developed. An investigation of practical realities of governance in four Australian SDI initiatives has been used to inform the development of this model. This paper provides an overview of the concepts of governance, presents some key findings from the Australian SDI cases studies; and describes an initial conceptual model of governance.