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During the analysis of multi-transistor circuits, the need arises to evaluate the time delay or the power consumption of the circuit. Due to the complexity of the transistor model, several complicated equations arise from which a compact-form solution cannot be obtained and a suitable physical insight cannot be drawn. With this regard, two contributions are presented in this paper. The first one is a fully analytical parameter extraction approach to be applied on the MOS transistors. The second one is a quantitative method for simplifying the analysis of MOS circuits by modelling the MOS transistor by a suitable equivalent resistance adopting the time-delay or the power-consumption equivalence criteria. The parameter-extraction method is verified by using the extracted parameters in the derived expressions according to the second contribution. Compared to other representations, the agreement of the proposed model with the simulation results is very good. [ABSTRACT FROM AUTHOR]

A spherical pendulum is a 2 degree-of-freedom mechanism consisting on a rod whose tip moves on the surface of a sphere. It is common to use two angular coordinates to describe such a system. This paper proposes the use of a non-minimal set of coordinates for modelling and controlling a fully-actuated torque-driven spherical pendulum. These coordinates is merely for the purpose of showing the application of unit quaternions as a useful tool for dealing with the orientation of rigid bodies. First, we recall the properties of unit quaternions, and explain how they can be employed for the definition of such non-minimal pendulum coordinates. Later, the control objective for orientation regulation is established and an inverse-dynamics controller, which uses joint displacement and velocity measurements but also some non-minimal states for the orientation error, is proposed. The stability analysis shows the fulfilment of the control objective and is validated through simulations. [ABSTRACT FROM AUTHOR]

This paper presents the mathematical modelling of an Electro-Hydraulic Valve Actuator (EHVA) prototype and its application to the design of cycle-by-cycle Valve Lift Control(VLC). EHVA is rated in the technical literature as an apparatus enabling Variable Valve Actuation (VVA) and implementation of advanced combustion concepts in future camless engines. It is, therefore, a first step towards the development of camless engines in which valve lift and timing can be freely adjusted valve-by-valve and cycle-by-cycle. Particular attention is paid to parameter identification aimed at obtaining a predictive simulation model of valve lift trajectories and valve parameters (e.g. lift, duration, area) for a wide range of system inputs. An energy loss assessment of a valvetrain based on EHVAs is described, and the results are compared with those obtained with a traditional cam-based valvetrain. The validated model is then used to build detailed numerical maps of valve parameters that are fundamental for setting up cycle-by-cycle controllers of valve parameters. Hence, the authors present the design of a cycle-by-cycle controller of maximum valve lift, the performance of which is tuned by simulations and then verified experimentally. [ABSTRACT FROM AUTHOR]

Within the field of environmental and hydrologic modelling, there is a growing recognition of the scientific and educational value of sharing both model programs (i.e. the codes that formulate a model) and model instances (i.e. specific input files and model parameterizations). Indeed, numerous cyberinfrastructure tools have been created in recent years to simplify linking, executing, and sharing models. Multiple challenges hinder the adoption of such systems by modelling communities. These can include technological barriers such as installing and managing software and internet systems as well as social barriers such as a culture of not sharing models due to concerns over private or otherwise proprietary information. In some cases, model-sharing platforms are not easily replicated or implemented to fit the needs of a specific modelling community. This paper presents the design and implementation of a model-sharing repository and a model-viewing application, specifically for the EPANET modelling community – the pattern and structure of which could be easily adopted by any modelling community – using existing open source cyberinfrastructure. We used HydroShare as the backend data store for the EPANET model program, model instances, and metadata, and we used the rapid app development capabilities of Tethys Platform framework to create a web-based front-end for the repository and viewer. Results of this experimental work include a functional model repository based on less than 700 lines of code and a light-weight model viewer application that encompasses nearly 100% of the legacy EPANET desktop GUI's functionality. [ABSTRACT FROM AUTHOR]

The bond graph (BG) method is an appropriate tool to model hybrid systems. The automated extraction of state equations from BG is the main drawback of this method. In this paper, a new method has been presented to simply extract the state equations from BG (SEBG method). Initially, SEBG has converted the BG model to the bond-element table (BE-table) to gain all the information of BG in a systematic representation. It has then formed a set of algebraic equations using elements' functions (E-functions) and found the power variables by solving them. Finally, the system's state equations are established using BE table, power variables, state vector, and states' functions, based on the fact that only the relations of inertial and capacity elements contain the first-order differential equations. Moreover, the simplicity and practicality of SEBG have been examined for finding the state equations of two systems. [ABSTRACT FROM AUTHOR]

The finite-difference (FD) scheme is extensively applied in seismic modelling, imaging and inversion due to its advantages of large-scale parallel computing and programming. However, numerical dispersion caused by using a difference operator in substitution for the differential operator is non-negligible, which reduces the accuracy of the modelling and can lead to some misinterpretations. In addition, the computing resources required by the FD scheme is highly demanding when dealing with large models, which limits its applicability. In this paper, a new optimised FD scheme is proposed, which is based on an improved particle swarm optimisation (PSO) algorithm. We improve the conventional PSO algorithm by introducing strategies related to local learning and global learning, which contribute to accelerating the convergence rate and effectively avoiding getting trapped in local extrema. Then, the improved PSO algorithm is used to improve the conventional FD scheme. Dispersion analysis and numerical modelling demonstrate that the low-order optimised FD scheme can achieve higher accuracy than a high-order conventional operator. Compared with the conventional FD scheme and a FD scheme based on the Remez exchange algorithm, the optimised FD scheme based on the improved PSO algorithm can more efficiently suppress numerical dispersion and increase computational efficiency. [ABSTRACT FROM AUTHOR]

This paper presents a review of Computable General Equilibrium (CGE) model applications for spatial economic and transport interaction modelling. This paper has three objectives (1) To deliver an up to date and comprehensive literature review on applications of CGE models in transportation, (2) To analyze the different methodological approaches and their theoretical and practical advantages and disadvantages, and (3) To ultimately provide guidance on designing CGE models for various transportation analyses. The content of the paper is as follows: first, a brief introduction to CGE models is provided. The history of CGE models is traced, ranging from their origins and seminal applications in economics, to their eventual adoption in transportation research. This is followed by a comprehensive review of the application of CGE models to transport projects and policies. Various applications in transportation are reviewed in terms of their intended application, as well as their treatment of space and time. Finally, these applications are contrasted with respect to their methodological approaches, with a close examination of various influential model choices. Here, the essential design choices made within these model applications are explained and debated, to clearly elaborate on the workings of the models and the design choices facing CGE model developers. [ABSTRACT FROM AUTHOR]

In the past decade, several publications have shown that it is advisable to design an advanced driver assistance system using a shared control structure. This paper is concerned with the modelling and verification of an interactive steering control strategy between a driver and an active front steering (AFS) controller to investigate the complex interactions between human driver and an AFS system. Using game theory as a general framework, a more comprehensive mathematical model system of interactive steering control potentially applicable to explore human drivers’ behaviours in shared control of intelligent vehicles is presented and discussed in this paper. The effects of different information patterns, namely the open-loop pattern and the closed-loop feedback pattern on modelling shared steering control between driver and AFS have been investigated. Simulation and hardware-in-loop implementation results prove the validity of steering interactive modelling in different game information patterns. Specifically, the results show that, in the Nash equilibrium strategy situation, the driver and the AFS controller may become more rational and reasonable in the process of completing the same dynamic task in the closed-loop feedback information patterns compared to the open-loop ones; and the differences between feedback Nash and feedback Stackelberg may depend on the step size of discretisation. [ABSTRACT FROM AUTHOR]

This paper aims to test different methods used for assessing sediment yield indices to identify hotspots and rank sediment yield hotspots. This process includes the assessment of the entropy weighting (EW), fractal dimension (FD), slope length gradient (SL), and sediment connectivity (SC) methods. The indices at different sub-catchment levels were applied in the Ilanlu catchment (Iran) and organized based on five sediment hazard classes. To assess the performance of sediment hazard mapping, a method of superimposition was used and assessed with the erosion potential model (EPM). The superimposition showed that 8, 10, 4 and 9 sub-catchments, based on the degree of susceptibility, obtained the highest results from FD, EW, SL and SC, respectively, compared with the EPM model. The results show that EW and SC methods can achieve greater performance than FD and SL in identifying sediment production hotspots. [ABSTRACT FROM AUTHOR]

Background: Advocacy through the work of many scholars in physical education and sport pedagogy highlights a significant direction towards which physical education is moving in light of calls for change. Importantly, and despite the 'newness' of the terms, 'pedagogical models' and 'Models-based Practice' (MbP) are beginning to shape the vocabulary of physical education and sport pedagogy. Purpose: To ask what happens if we take some of the 'good stuff' associated with models and apply it in a different way while also taking some of the critical points raised towards models into consideration. Put simply, we (as scholars with different views on MbP) want to step off the beaten track to take a road less travelled and engage in a respectful, agonistic debate about the 'M' and the 'P' in MbP. Key arguments: From a practical perspective, the diversity of the language used in describing models and practices in physical education indicates both a growing excellence and tradition in the field and a degree of confusion. A number of phrases are currently used to identify the same concept with individuals unaware of alternative language use. At the heart of this paper lies the manner in which one interprets the use of the terms 'model', 'practice' and 'practise'. Discussion: Given the 'hope' inherent in pedagogical model development and implementation, we acknowledge that many of the negative or unintended consequences often arise as a result of the 'happening' both in research and in practice. However, by thinking in terms of what it is in students' actions that teachers and researchers should pay attention to in order for them to see what students learn, and in what direction this learning is developing, we are better able to see the outcomes of using MbP. In this way, the hope embedded in the chosen model, and the happenings teachers or researchers aspire to see, could be better aligned. Modelling and practicing through the focus on adaption and negotiation in various complex contexts has the potential to expand the field more than blueprints that potentially narrow the field. Conclusions: By recognising the dangers inherent in an essentialist notion of models (i.e. by nouning or proper nouning them), and by remembering the roles set aside for teachers in the development of pedagogical models, it is important that the practising of MbP always retains a very real sense of becoming. By continuing to problematize the M and the P, and by engaging in respectful and agonistic debate, we are better able to unite the hope and the happening of MbP. [ABSTRACT FROM AUTHOR]

Transparency and openness are broadly endorsed in energy and environmental modelling and analysis, but too little attention is given to the transparency of value-laden assumptions. Current practices for transparency focus on making model source code and data available, documenting key equations and parameter values, and ensuring replicability of results. We argue that, even when followed, these guidelines are insufficient for achieving deep transparency, in the sense that results often remain driven by implicit value-laden assumptions that are opaque to other modellers and researchers, and that may not be understood by wider audiences to be controversial. This paper identifies additional best practices for achieving transparency by highlighting issues where disagreement over value judgements will persist for the foreseeable future. Recommendations for deepening transparency are developed by learning from successes and ongoing challenges represented in three case studies. We provide recommendations to accelerate the adoption of additional best practices for deepening transparency of energy and environmental modelling in policy-relevant domains, increasing stakeholder participation with non-modellers, and encouraging interdisciplinary dialogue. Key policy insights Achieving all of the goals associated with transparency requires more than current practices of providing open source data, code, and model documentation. Greater interdisciplinary dialogue could improve transparency beyond current practices, including in model development, application, and communications. Better practices for addressing contentious and value-laden assumptions include providing accessible documentation for non-specialists, increasing policymaker participation to ensure that model outputs can inform questions, and performing sensitivity analyses that cover a range of reasonable views about value-laden assumptions. Energy and environmental modellers should account for audience-specific considerations to promote transparency, especially accounting for needs of non-modellers such as policymakers. [ABSTRACT FROM AUTHOR]

The modelling technique contributes to understanding noise nature and properties. Prior work has established a primary random noise model in the homogeneous medium, however, this strict assumption of the medium may be not valid under the actual environment so that will reduce the modelling accuracy. Therefore, in this paper, a random noise model is established in the mixed heterogeneous medium to improve the modelling accuracy, so the scattered mechanism is used to describe the random noise field in the heterogeneous medium. Since the perturbation method is always applied to solve the scattering problem, the noise wave field can be regarded as the superposition of the perturbation wave field and the unperturbation wave field. Consequently, the random noise model reveals that the desert random noise is mainly caused by the wind, and it concentrates on 1–20 Hz. A detailed comparison is made between the noise model established in the homogeneous medium and the proposed noise model, the results illustrate that the proposed noise model is more similar to the actual noise. Besides, for embodying the model's practical application value, the proposed noise model is adopted as the background noise to determine the VMD (variational mode decomposition) denoising parameters. The satisfactory denoising performance supports the usefulness of the proposed noise model for the random noise attenuation. [ABSTRACT FROM AUTHOR]

This paper presents an overview of the recent developments in traffic flow modelling and analysis using macroscopic fundamental diagram (MFD) as well as their applications. In recent literature, various aggregated traffic models have been proposed and studied to analyze traffic flow while enhancing network efficiency. Many of these studies have focused on models based on MFD that describes the relationship between aggregated flow and aggregated density of transport networks. The analysis of MFD has been carried out based on experimental data collected from sensors and GPS, as well as simulation models. Several factors are found to influence the existence and shape of MFD, including traffic demand, network and signal settings, and route choices. As MFD can well express the traffic dynamics of large urban transport networks, it has been extensively applied to traffic studies, including the development of network-wide control strategies, network partitioning, performance evaluation, and road pricing. This work also presents future extensions and research directions for MFD-based traffic modelling and applications. [ABSTRACT FROM AUTHOR]

Modelling the dynamics of evolutionary competing species on a physical grid is a challenging modelling problem. This paper presents a novel modelling approach for synthesizing evolutionary dynamics of competing species using a spatial game perspective. This modelling approach describes the movement of players (‘species’ in our context) across a lattice. The model is based on a payoff function which controls the move likelihood and direction of the players (‘predators’ and ‘preys’). Using simulated results, the paper provides a comparison between the spatial game model and an existing predator-prey dynamic model. Finally, a case study is performed to illustrate the application of this formalism and validate the model. [ABSTRACT FROM AUTHOR]

Bridge dynamics and aerodynamics have been in many cases overlooked in the design stages and consequent low behaviour performance and safety margin have been not rarely observed and detected by means of structural monitoring of the bridge soon after it is brought into full service. In this paper, a selection of important issues regarding design and practical requirements for a high structural performance of main components of conventional and cable-stayed bridges are pointed out and discussed briefly. The paper encompasses sections describing some relevant aspects regarding the numerical and physical modelling of the structural system and the mathematical modelling of the dynamic and aerodynamic loads. Special attention is given to the dynamic interaction between vehicles and structures of roadways and railway bridges and also to the aeroelastic analyses of bridges′ behaviour and their consequent implications on the structural performance of a bridge during its service life. Case examples of actual bridges subjected to dynamic forces produced by the traffic of heavy vehicles and by the wind action are explored to depict the main sources of problems which in some cases caused structural misbehaviour. Some practical measures to improve the behaviour and performance of bridge structures are outlined. [ABSTRACT FROM AUTHOR]

Motorised two-wheeler (MTW) has emerged as the most widely used transportation mode for short distance trips in many Asian and European countries because of its affordable price and flexibility in manoeuvring through traffic. Its small size and aggressive riding patterns can considerably affect the overall traffic flow characteristics and safety. Modelling the characteristic behaviour and complex movement patterns of motorised two-wheelers is essential due to their pronounced role in microscopic traffic simulations, traffic management strategies, safety evaluation, transport planning and intelligent transportation systems. This paper begins with an overview of the determinant factors used for MTW modelling, followed by a critical review of various modelling approaches that have been adopted to depict the movement patterns of MTWs. The review concentrates on (i) identifying the factors mostly studied with respect to MTW-research, (ii) discussing the potential and limitations of each modelling approach and (iii) reporting some of the aspects that need further consideration for modelling MTWs in heterogeneous mixed traffic streams. The findings of the paper suggest that an integrated approach can be more viable to depict the unique riding patterns of motorised two-wheelers and some possible directions for future studies are also proposed. [ABSTRACT FROM PUBLISHER]

The quantitative analysis of organisations as systems can only proceed with confidence if the underlying models are truly representative and have been validated. Without such models, the outcomes of any quantitative analysis can be criticised. This paper contends that organisations are perhaps one of the most confronting systems to model, and validation of any models proposed by researchers is fraught with obstacles. This is not a reflection on the ability of researchers, but rather a commentary on the nature of organisations. It follows that the state-of-the-art of understanding organisations is quite primitive when compared with engineering and technical systems. The difficulties in modelling and validation lie in a number of issues, and these are outlined in the paper. These issues include the hierarchical and multilevel nature of organisations, people involvement, homomorphism, the diversity of organisations, culture, personal and organisational value systems, work division, organisational structures, coordination, and span of management. [ABSTRACT FROM AUTHOR]

This paper describes the development of the first operational seasonal hydrological forecasting service for the UK, the Hydrological Outlook UK (HOUK). Since June 2013, this service has delivered monthly forecasts of streamflow and groundwater levels, with an emphasis on forecasting hydrological conditions over the next three months, accompanied by outlooks over longer time horizons. This system is based on three complementary approaches combined to produce the outlooks: (i) national-scale modelling of streamflow and groundwater levels based on dynamic seasonal rainfall forecasts, (ii) catchment-scale modelling where streamflow and groundwater level models are driven by historical meteorological forcings (i.e. the Ensemble Streamflow Prediction, ESP, approach), and (iii) a catchment-scale statistical method based on persistence and historical analogues. This paper provides the background to the Hydrological Outlook, describes the various component methods in detail and then considers the impact and usefulness of the product. As an example of a multi-method, operational seasonal hydrological forecasting system, it is hoped that this overview provides useful information and context for other forecasting initiatives around the world. [ABSTRACT FROM AUTHOR]

Carmichael's paper offers a framework for civil engineering systems work. The approach is rigorous. But equally rigorous should be the principles underlying the work, including a clear and unambiguous defining purpose and a careful attention to modelling principles. That is, a rigorous process is just as important as a rigorous framework. Suggested additions to the proposed framework are: purpose, information (including uncertainty and quality), modelling, topology and value. [ABSTRACT FROM AUTHOR]

In this paper, the Heterogeneous Quasi 1-D model for steady combustion of AP–HTPB propellants is extended to the unsteady regime. The extended model is used to calculate the pressure-coupled frequency response ( R p ) of low-smoke (non-aluminised) multi-modal AP–HTPB propellants. The R p of a multi-modal propellant is expressed in terms of that of the individual binder-matrix coated AP particles constituting the statistical particle path. The weighting function, as expected from the serial burning approach, is the burn-time of particles. A closed-form expression is derived for the R p of the particles by perturbation analysis of the quasi 1-D burn rate model. In this equation, all except the two parameters that quantify the amplitude ( A c ) and phase ( φ c ) of fluctuating heat flux on the solid side of the interface, are shown to be from the steady-state model. This result establishes a strong connection between the steady and unsteady framework as compared to earlier models, where R p → n (propellant pressure index) as f → 0 was explicitly imposed. The model is used to predict R p for a few low-smoke compositions. Effects of AP particle size distribution, mean pressure and initial temperature are brought out. When expressed as R p / n vs f s (non-dimensional frequency based on conduction time scale), the peak response magnitude is of O (1) and occurs close to non-dimensional frequency ( f s = f α / r ˙ ¯ 2 ) value of 1. While this conclusion is in line with the earlier results, it does not explain the ubiquitous nature of acoustic instability in tactical missile rockets, which requires the peak response to be at least an order of magnitude higher than n. Burn rate oscillations associated with the binder-melt effect caused by inhibitors is brought out as the most likely mechanism for the observed instabilities. Methods to extend the theory to include this effect is outlined. [ABSTRACT FROM AUTHOR]

This paper presents CFD modelling of hydrogen-air deflagrations. The proposed mathematical models are validated with the experiments provided to SARNET2 (Severe Accident Research NETwork of Excellence 2) project [A. Bentaib, A. Bleyer, N. Chaumeix, B. Schramm, P. Kostka, M. Movahed, H.S. Kang and M. Povilaitis, Final results of the SARNET Hydrogen deflagration Benchmark Effect of turbulence on flame acceleration. (2012), pp. 1–15; A. Bentaib, A. Bleyer, N. Meynet, N. Chaumeix, B. Schramm, M. Höhne, P. Kostka, M. Movahed, S. Worapittayaporn, T. Brähler, H. Seok-Kang, M. Povilaitis, I. Kljenak and P. Sathiah, SARNET hydrogen deflagration benchmarks: Main outcomes and conclusions. Ann. Nucl. Energy 74 (2014), pp. 143–152. doi:]. The goal of SARNET2 project was to investigate the effect of blockage ratio on flame propagation and pressure evolution during deflagration of a lean mixture of hydrogen and air. Three blockage ratios were tested: BR = 0, 0.33 and 0.63. The experiments were carried out in the ENACCEF facility. The proposed mathematical models test the effect of turbulence models and radiative heat losses on flame front position and absolute pressure in the testing facility. A good agreement between the calculated and experimental results for the three BRs is found for the SST k-ω model alone and in combination with the γ transition model when radiative heat losses are accounted for in the modelling. In addition, an unstable tulip flame is evidenced in our CFD simulations what corroborates previous reports on premixed combustion in a closed tube. [ABSTRACT FROM AUTHOR]

This paper presents an overview of the recent developments in traffic flow modelling and analysis using macroscopic fundamental diagram (MFD) as well as their applications. In recent literature, various aggregated traffic models have been proposed and studied to analyse traffic flow while enhancing network efficiency. Many of these studies have focused on models based on MFD that describes the relationship between aggregated flow and aggregated density of transport networks. The analysis of MFD has been carried out based on experimental data collected from sensors and GPS, as well as simulation models. Several factors are found to influence the existence and shape of MFD, including traffic demand, network and signal settings, and route choices. As MFD can well express the traffic dynamics of large urban transport networks, it has been extensively applied to traffic studies, including the development of network-wide control strategies, network partitioning, performance evaluation, and road pricing. This work also presents future extensions and research directions for MFD-based traffic modelling and applications. [ABSTRACT FROM AUTHOR]

Water from the alluvium of ephemeral rivers in Zimbabwe is increasingly being used. These alluvial aquifers are recharged annually from infiltrating floodwater. Nonetheless, the size of this water resource is not without limit and an understanding of the hydrological processes of an alluvial aquifer is required for its sustainable management. This paper presents the development of a water balance model, which estimates the water level in an alluvial aquifer recharged by surface flow and rainfall, while allowing for abstraction, evaporation and other losses. The model is coupled with a watershed model, which generates inflows from upland catchment areas and tributaries. Climate, hydrological, land cover and geomorphological data were collected as inputs to both models as well as observed flow and water levels for model calibration and validation. The sand river model was found to be good at simulating the observed water level and was most sensitive to porosity and seepage. [ABSTRACT FROM AUTHOR]

In this paper, a simple method is introduced for the computational modelling of multiphase materials, and for the approximation of their mechanical response. The two-dimensional microstructures of six asphalt concrete specimens are selected; three of the specimens have 'low'-, and three have 'high' aggregate fraction. A grid is used to divide the surface of each microstructure into square cells. The procedure of grid division is applied from 1 up to 100 divisions per side (i.e. up to 10,000 cells in the grid-divided specimen). To obtain an approximation of the mechanical response of the microstructure, the properties of the cells are estimated using three simple interpolation rules between the properties of the two phases, i.e. asphalt matrix and rock aggregates. It is found that the interpolation rules can yield reasonably representative results depending on the aggregate fraction of the microstructures and the number of divisions/cells in the grid. The grid-divided specimens allow approximating the overall mechanical response of the microstructures, and characteristics such as strain concentrations, overall deformations, and resulting force. [ABSTRACT FROM AUTHOR]

The development of children's lie-telling abilities is considered to be a social and cognitive milestone. While occasional lying is developmentally appropriate, the use of frequent, antisocial lies as a maladaptive problem-solving mechanism can indicate behaviour problems. Since lying is often considered a moral transgression, researchers should examine lying from the perspective of moral theory to understand children's reasons for lying, which may help to understand how chronic lying develops. A theoretical framework, namely the social cognitive process of moral disengagement (MD) could not only provide new insight into children's justifications for telling common lies, but also atypical, antisocial lies. This paper aims to describe how MD may be applied to explain children's justifications for lying, especially antisocial lies, and how adults can address MD by modelling the positive consequences of truth-telling, to promote honesty in children. [ABSTRACT FROM AUTHOR]

This paper establishes the models of rotating air layer to predict the pressure of the air around the solid and grinding wheel of different dimensions and rotating at different speeds and finds the factors affecting the flow. Initially, a theoretical model has been developed from the Navier–Stokes (N–S) equation and compared with the experimental values at each stage. Results show that the effects of two proposed novel effect, namely 'compensating air' for the solid wheel and 'Majumdar-air' for the grinding wheel, along with the effect of surface and centrifugal force are responsible for the additional growth of air. The effects of 'compensating air' and 'Majumdar-air' near the wheel surface have been found to be 33% and 66% of the total pressure for the solid and grinding wheel of the same dimension, respectively, rotating at 2880 rpm. These two effects are responsible for a significant deviation of the experimental data from the theoretical model. Further, the theoretical model has been modified by introducing a correction factor in the equation. Flower Pollination Algorithm (FPA) has been used to optimize the parametric values of the modified model with a minimal error. The output of the modified model has been found consistent with the experimental result. [ABSTRACT FROM AUTHOR]

Cut-off grade classifies the available supply of ore (valuable) and waste material within a mineralised deposit. Given the mining, processing and refining limitations of a mining operation, an optimal cut-off grade policy ensures that the flow of ore from the mine to the processing and refining facilities is maintained at the maximum possible throughput. This policy defines a schedule of cut-off grades along with corresponding quantities of mineralised material to be mined, processed and metal refined in each period of the scheduling horizon. The criteria that controls the development of cut-off grade policy aligns with the strategic objectives of an operation in order to maximise the discounted value (net present value or NPV) over the life of operation. This paper proposes a new mixed integer linear programming (MILP) based model that maximises NPV subject to the mining, processing, refining capacity constraints and develops an optimal cut-off grade policy for an open pit mining operation with multiple processing streams. An implementation of the proposed method on hypothetical and realistic data promises a relatively higher NPV as compared to the traditional Lane's approach practiced in the mining industry. [ABSTRACT FROM AUTHOR]

In the past, population growth in Australia's Northern Territory, as in other peripheral parts of high-income countries, has been driven by internal labour migration and migration from outside of Australia. These have been contributing to the high population turnover experienced in peripheral areas. Since 2010, the Northern Territory has experienced low (and even negative) population growth, and public policy is currently focused on migration as a lever to reverse this trend. However, the extent to which the characteristics of migrants influence the potential for longer-term population growth is poorly understood. This paper uses a new method to analyse the contributions of various types of migrants to both population turnover and retention. Two major sets of findings emerge: First, the significance of separating newer in-migrants from longer-term residents when analysing migration patterns; and secondly, the contribution of age, gender, Indigenous status, international origin, wages and industry of employment to the Northern Territory's population turnover. The research suggests that current forms of migration favour people who are likely to stay for only short periods, and have high wage demands. The main policy inference is that long-term population growth will likely not eventuate unless new forms of migration can be stimulated. [ABSTRACT FROM AUTHOR]

Seismic inversion and reservoir identification are complicated problems with integrated data sets and need a velocity or density model to ensure the stability of the results. However, an elastic parameter model, such as velocity or density, is difficult to obtain with high precision by conventional migration or interpolation, especially during the early exploration stage, which contains few available logging data. The kriging method has proved to be an effective technique for mineral exploration and petroleum geophysics, and has led to a series of expansive techniques in earth science. In this paper, we proposed a new matching method, base value compensation (BVC), for integrating multiscale data sets into model elastic parameters. Considering the variety of original information, we used multiple constrain cokriging for three types of data set at different scales. These three data sets come from logging, seismic attributes and sedimentary facies information. The P-wave velocity model is stable and more representative of the subsurface condition, but we found that this method produces few points with anomalous values in the density model. Those abnormal points cause substantial loss of geological detail at sedimentary boundaries. In most modelling methods, this shortcoming is due to the fact that these three input parameters have significantly different properties. The proposed method can effectively solve this problem by matching the input data sets at a similar observational scale before modelling. We demonstrated this method using a case study in the South China Sea. The decrease in abnormal points in the final modelling results verifies the effectiveness of BVC. [ABSTRACT FROM AUTHOR]

Flood inundation is a common natural disaster and a growing development challenge for many cities and thousands of small towns around the world. Soil features have frequently altered with the rapid development of urbanised regions, which has led to more frequent and longer duration of flooding in urban flood-prone regions. Thus, this paper presents a geographic information system (GIS)-based methodology for measuring and visualising the effects on urban flash floods generated by land-use changes over time. The measurement is formulated with a time series in order to perform a dynamic analysis. A catchment mesh is introduced into a hydrological model for reflecting the spatial layouts of infrastructure and structures over different construction periods. The Geelong Waurn Ponds campus of Deakin University is then selected as a case study. Based on GIS simulation and mapping technologies, this research illustrates the evolutionary process of flash floods. The paper then describes flood inundation for different built environments and presents a comparison by quantifying the flooding extents for infrastructure and structures. The results reveal that the GIS-based estimation model can examine urban flash floods in different development phases and identify the change of flooding extents in terms of land-use planning. This study will bring benefits to urban planners in raising awareness of flood impact and the approach proposed here could be used for flood mitigation through future urban planning. [ABSTRACT FROM PUBLISHER]

Satisfying the accommodation needs of the world's urban population requires high-rise buildings. Accommodating some of 3.5 billion urban population in complex apartments has created challenges including the human scale understanding of complex 3D property rights, and engineering and architectural features relating to building interiors. Technological developments have brought about the prevalence of inexpensive systems such as gaming consoles and smartphones. This paper explores the use of Kinect for Windows (a consumer grade technology that was originally designed for computer gaming purposes) to survey indoors in 3D. This paper presents the result of an investigation into the utility of this widespread and economical technology for 3D surveying of interiors of buildings in relation to Surveying (Cadastral Survey) Regulation 2005, Victoria, Australia. Building on the results of the investigation, the paper argues that such a technology has the potential to be used in other application domains and crowdsourcing 3D indoor information. [ABSTRACT FROM AUTHOR]

The use of biomass has been promoted to meet the need for sustainable production of ethylene, which is the most used petroleum-derived in the polymer industry. Ethanol is an alternative feedstock to yield the so-called bio-ethylene through catalytic dehydration in fixed-bed reactors. As the reaction system is strongly endothermic, it is very important to know accurately the reactor temperature to assure the process performance. However, in the industrial context, the process measurements are often uncertain and not all variables can be directly measured online. In this regard, this paper analyses the mathematical modelling and numerical simulation of the ethanol catalytic dehydration and contributes with a monitoring scheme using the Bayesian method known as particle filter. Numerical simulations helped understanding the process behaviour and locating the best position for the temperature sensor in the reactor. From temperature measurements, the proposed inferential tool estimates hidden state variables and unmeasured disturbances, using Sequential Importance Resampling algorithm for the particle filter. The proposal is investigated according to the number of particles and the criterion total error reduction. The results show that the monitoring scheme is able to estimate satisfactorily the process variable profiles, as the temperature and chemical conversion, along the reactor length. [ABSTRACT FROM AUTHOR]

Fatigue behaviour of materials is traditionally performed on probes that ensure that stresses (or strains) are very uniform. This is a situation seldom encountered in most adhesively bonded joints, where stresses usually peak at the end of the overlaps. This paper presents a relatively simple model to predict the fatigue behaviour of glued-in rods (GiR) involving hardwood in previously investigated in an extensive experimental campaign. The model is based on strength and stiffness degradation of the components of the GiR, which were experimentally estimated in small scale tests. Based thereupon, Finite Element Analysis (FEA) was used to estimate the effect of material degradation on the residual strength of the GiR, which was then interpreted as S-N-curves. The influence of several parameters, e.g. strength and stiffness degradation rates and the magnitude of the residual strength threshold were numerically investigated. The result showed that it is possible, using a practitioner adapted numerical model, to predict the fatigue behaviour of GiR, based upon comparatively simple fatigue characterisation on their components. [ABSTRACT FROM AUTHOR]

Risk methods are powerful and versatile, but they have limitations and subtle traps. The paper explores the nature of risk. There are three main difficulties. First, there is a problem with quality and completeness of information. Lack of precise information means that likelihood and consequences have to be estimated, so the information is vulnerable to biases: some are explored. Secondly, there is a serious problem of completeness in risk models, where omissions can lead to serious consequences. Unexpected events, sometimes called 'black swans', abound. Thirdly, the conjunction of very small probabilities and major consequences can lead to unreliable and dubious results. Applications areas considered are structural engineering, project management and risk management generally. There are situations where a resilience approach is preferable to risk. [ABSTRACT FROM AUTHOR]

Modelling is a central activity in practical engineering and something that is also useful in engineering education research (EER). Additionally, qualitative research methods have found important applications in engineering research, although their use in EER has not always been widely accepted. Design science research is a qualitative research approach in which the object of study is the design process, i.e. it simultaneously generates knowledge about the method used to design an artefact and the design or the artefact itself. This paper uses techniques from design science research to analyse the method used when deriving the 'learning of a complex concept' (LCC) model, which we developed while designing teaching sequences for a course on electrical engineering. Our results demonstrate the value of design science research in EER and suggest that the LCC model is generally applicable in this field. [ABSTRACT FROM AUTHOR]

Automated vehicles (AVs) could completely change mobility in the coming years and decades. As AVs are still under development and gathering empirical data for further analysis is not yet possible, existing studies mainly applied models and simulations to assess their impact. This paper provides a comprehensive review of modelling studies investigating the impacts of AVs on travel behaviour and land use. It shows that AVs are mostly found to increase vehicle miles travelled and reduce public transport and slow modes share. This particularly applies to private AVs, which are also leading to a more dispersed urban growth pattern. Shared automated vehicle fleets, conversely, could have positive impacts, including reducing the overall number of vehicles and parking spaces. Moreover, if it is assumed that automation would make the public transport system more efficient, AVs could lead to a favouring of urbanisation processes. However, results are very sensitive to model assumptions which are still very uncertain (e.g. the perception of time in AVs) and more research to gain further insight should have priority in future research as well as the development of the models and their further adaptation to AVs. [ABSTRACT FROM AUTHOR]

This paper introduces the concept and develops the theory for a push-pull actuator made by winding a thin shape memory wire on a solid rubber cylinder. The incompressibility of the rubber converts the thermomechanical contraction of the heated wire in twice as much axial strain available in the rubber core. The intrinsic elastic backup provided by the core allows push-pull action of the device. Based on the assumption of both material and geometric linearity, a simple theoretical model is developed, which culminates in a simple closed-form equation for the output stroke of the actuator. The theoretical predictions closely agree with refined finite element simulations, anticipating a net stroke of about 5-6% of the overall actuator length, depending on the outer load applied. The working principle of the actuator and the accuracy of the model are validated by tests on a proof-of-concept prototype. [ABSTRACT FROM AUTHOR]

The behaviour of many small systems, such as a family or a football team, epitomizes the famous Gestalt slogan of a “Whole which is different from the sum of its parts”. However, and in the context of these small cognitive systems, conceptualizing and measuring the extent and the way in which a whole is different from the sum of its parts is a non-trivial challenge. One possible direction for addressing this challenge involves measuring the extent in which the entropy of the whole is non-additive, meaning different from the sum of the entropy of its parts. However, measuring divergence from additivity is far from trivial. In this short paper, we propose a simple procedure for measuring divergence from additivity and illustrate the procedure by analysing the behaviour of a soccer team. [ABSTRACT FROM AUTHOR]

This paper discusses the use and impact of formative feedback and scaffolding to develop outcomes for complex problem solving in a required first-year course in engineering design and practice at a medium-sized research-intensive Canadian university. In 2010, the course began to use team-based, complex, open-ended contextualised problems to develop problem solving, communications, teamwork, modelling, and professional skills. Since then, formative feedback has been incorporated into: task and process-level feedback on scaffolded tasks in-class, formative assignments, and post-assignment review. Development in complex problem solving and modelling has been assessed through analysis of responses from student surveys, direct criterion-referenced assessment of course outcomes from 2013 to 2015, and an external longitudinal study. The findings suggest that students are improving in outcomes related to complex problem solving over the duration of the course. Most notably, the addition of new feedback and scaffolding coincided with improved student performance. [ABSTRACT FROM AUTHOR]

In this paper, critical review of various work done in the areas of wind energy resource, modelling of wind energy conversion system (WECS) and issues regarding wind power integration into the grid are presented with the aim of examining the development, progress, achievements and direction of research. Some of the findings show that every site is unique; therefore, no generic conclusion can be drawn with regards to wind characteristics and the wind power potential of locations. The study also reveals that there is no single model of WECS. The model to be adopted will depend on the problem to be solved. This paper is useful in providing background details for wind turbine designers, researchers and practical engineers who are new in the field of wind energy. [ABSTRACT FROM AUTHOR]

In this paper, the feasibility of using evolutionary computing for solving some complex problems in geotechnical engineering is investigated. The paper presents a relatively new technique, i.e. evolutionary polynomial regression (EPR), for modelling three practical applications in geotechnical engineering including the settlement of shallow foundations on cohesionless soils, pullout capacity of small ground anchors and ultimate bearing capacity of pile foundations. The prediction results from the proposed EPR models are compared with those obtained from artificial neural network (ANN) models previously developed by the author, as well as some of the most commonly available methods. The results indicate that the proposed EPR models agree well with (or better than) the ANN models and significantly outperform the other existing methods. The advantage of EPR technique over ANNs is that EPR generates transparent and well-structured models in the form of simple and easy-to-use hand calculation formulae that can be readily used by practising engineers. [ABSTRACT FROM PUBLISHER]

This paper explores the potential for real-time urban flood forecasting based on literature and the results from an online worldwide survey with 176 participants. The survey investigated the use of data in urban flood management as well as the perceived challenges in data acquisition and its principal constraints in urban flood modelling. It was originally assumed that the lack of real-time urban flood forecasting systems is related to the lack of relevant data. Contrary to this assumption, the study found that a significant number of the participants have used some kind of data and that a possible explanation for so few cases is that urban flood managers or modellers (practitioners)maynot be aware they have the means to make a pluvial flood forecast. This paper highlights that urban flood practitioners can make a flood forecast with the resources currently available. [ABSTRACT FROM AUTHOR]

Investigation of various phenomena occurring in sewer systems is critical for increasing the sustainability of such systems. Such investigations also includes gross solids (GS) transport. GS transport may be affected by reduction of flows resulting from population decrease and/or reduced domestic water consumption. The present paper reports on the development of a model for describing GS velocity as a function of wastewater flow characteristics. The model was calibrated and validated with field experiments, in which two methods for GS tracking in sewers were developed, using small light sticks tracked by computerized light detector, and RFID based tracking. The model is integrated in a simulator which allows a description of the movement of individual GS through sewer systems. The developed model may assist in analysing existing sewer systems that are subject to changes in their input flows and prevent undesired failures (e.g. sedimentations, blockages, toxic gases) or in designing new systems. [ABSTRACT FROM AUTHOR]

Heritage buildings traditionally have been tackled from several points of view: architectonic features, architectural style, archaeology, history, etc. Documents derived from those studies were classified and put together to form the documentation for consultation, taking decisions about its conservation, and restoration. Such a document organisation has some inconveniences: objects composing the building were treated as isolated objects not related to its adjacent objects. Nowadays technology may help to discover the relationship between architectural objects forming heritage buildings. The tool that makes it possible to include functionality in architectural objects is BIM (Building Information Modelling). In this paper the historical evolution of Saint Jeromés Church in Baza will be analysed and stored in a functional model which includes geometry and its current state. We propose a procedure for building the BIM through its historical roots and evolution to be included in each remarkable object modelled from the point cloud surveyed. [ABSTRACT FROM AUTHOR]

Asphalt binder represents the main constituent of asphalt paving mixtures. The functional performance and durability of asphalt pavements strongly depend on the rheological and mechanical properties of the binder. Asphalt binder is a highly temperature susceptible material that becomes brittle and more prone to failure at low temperature, which may ultimately result in thermal cracking at the mixture level. Significant effort was devoted over the years to reduce the occurrence of this distress. For this purpose, a number of experimental methods were developed to characterise asphalt binders at low temperature. At the same time, different models were formulated to better understand and predict the material behaviour while extrapolating more information from the testing measurements. In this paper, a comprehensive review on the behaviour of asphalt binders at low temperature is presented. First, a synthetic introduction and background on the development of the criteria for asphalt binder low-temperature behaviour are provided. Then, the current testing procedures for characterising asphalt binders are presented and the validity of the current PG specification is discussed. Finally, the most significant modelling developments are reviewed. [ABSTRACT FROM AUTHOR]

The need for on-line information in any environment has led to the development of mobile satellite communication terminals. These high data-rate terminals require inertial antenna pointing error tolerance within fractions of a degree. However, the base motion of the antenna platform in mobile applications complicates this pointing problem and must be accounted for. Gimbaled motorised pedestals are used to eliminate the effect of disturbance and maintain uninterrupted communication. In this paper, a three-axis ship-mounted antenna on a pedestal gimbal system is studied. Based on the derived dynamic model of the antenna pedestal multi input-multi output PID andH∞linear controllers are designed to stabilise the antenna to keep its orientation unaltered towards the satellite while the sea waves disturb the antenna. Simulation results are presented to show the stabilisation performance of the system with the synthesised controllers. It is shown through performance comparison and analysis that the proposedH∞control structure is preferable over PID controlled system in terms of system stability and the disturbance rejection. [ABSTRACT FROM PUBLISHER]

Predicting the risk of traffic demands and delays exceeding critical limits at road junctions, airports, hospitals, etc., requires knowing how both mean and variance of queue size vary over time. Microscopic simulation can explore variability but is computationally demanding and gives only sample results. A computationally efficient approximation to the mean is used in many modelling tools, but only empirical extensions for variance in particular situations have been available. The paper derives theoretical formulae for time-dependent and equilibrium variance, believed to be novel and to apply generally to queues covered by the Pollaczek–Khinchin mean formula, and offering possible structural insights. These are applied in an extended approximation giving mutually consistent mean and variance estimates with improved accuracy. Tests on oversaturated peak demand cases are compared with Markov probabilistic simulation, demonstrating accuracy (R2 > 0.99) for typical random, priority-like (M/M/1) and traffic-signal-like (M/D/1) queues. Implications for risk analysis, planning and policy are considered. [ABSTRACT FROM AUTHOR]

Accurate prediction of equilibrium scour depth downstream of hydraulic structures has an important role in their appropriate design. In this paper, the applicability of artificial neural networks (ANNs) and adaptive neuro-fuzzy inference system (ANFIS) models in prediction of equilibrium scour depth is studied. Multi-layer perceptron neural network structure is employed for the training of the ANN models. Experimental data of published literature are used for training and testing the models. The equilibrium scour depth is predicted as a function of five input variables; apron length, sluice gate opening, issuing velocity of jet, tailwater depth and median sediment size. The comparison of results shows that ANN model provides a better prediction of scour depth than ANFIS as well as the previous empirical relationship obtained by regression analysis. However, the results indicate that both ANN and ANFIS models can successfully predict equilibrium scour depth. Finally, based on the sensitivity analysis, it was found thatd50has the greatest effect on equilibrium scour depth. [ABSTRACT FROM AUTHOR]

The few recent years have witnessed the appearance of a new kind of self-adaptive systems called cloud based-elastic systems. These systems are particularly appealing for their ability to maintain a decent quality of service and reduce a system’s operating cost at the same time. They achieve this by dynamically adjusting resources allocation in terms of elasticity. Meanwhile, complexity of structural and behavioural aspects related to cloud-based elastic systems increase the difficulty of designing and developing such systems. In this paper, we address this challenge by proposing a formal approach based on bigraphical reactive systems for modelling both structural and behavioural aspects of cloud-based elastic systems. In particular, we represent their behaviour in terms of client/application interactions and elasticity methods at different levels using bigraphical reaction rules. The feasibility of the proposed approach is illustrated through a motivating example running on the top of an Amazon Elastic Compute Cloud (EC2) infrastructure. Modelling cloud-based elastic systems using bigraphical reactive systems [ABSTRACT FROM PUBLISHER]

Suleymaniye was one of the most densely populated areas of Istanbul in the Ottoman period. In order to protect the traditional cultural identity of Suleymaniye region and bring it in line with contemporary living conditions, a new project has been created by the Istanbul Metropolitan Municipality. Within the framework of the research on cloud computing on architecture, this paper will present both the results of terrestrial laser scanning which was used to obtain 3D point clouds through 3D survey measurements and scans of silhouettes of streets and roads, which were then transposed into survey images and designed as an example of city modelling. Additionally, the study will cite examples of how this technology has been used in Suleymaniye region. [ABSTRACT FROM PUBLISHER]