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Understanding the effects of water absorption on the geometry of a paper sheet is important for inkjet printing applications, since internal moisture content differences may cause unacceptable out-of-plane deformations. The present work focuses on moisture-induced deformations due to a moisture content that is uniform over the thickness of the sheet. Large enough in-plane differences will cause the sheet to buckle, leading to a wavy pattern at the edges of the sheet. Two approaches are utilized to study this for levels of moisture content up to and including the threshold for buckling. An analytical approach, based on geometrically nonlinear plate theory (von Kármán theory), and a numerical one, using commercially available finite element software, are presented. As a first reference problem an isotropic circular plate, wetted uniformly at its center, is solved both analytically and numerically for the in-plane stress distribution, the buckling threshold, and the resulting buckling mode. Secondly, the same is done for an orthotropic rectangular plate, wetted at its edges. Here, in the analytical approach a Rayleigh–Ritz analysis is employed to approximate the buckling threshold. The latter is also calculated by numerical means. The results show that the methods provide results consistent with each other. [ABSTRACT FROM AUTHOR]

Cellulose partially converted to dialcohol cellulose has been identified as a potential breakthrough material for the production of bio-based, complex, double-curved surfaces due to its extensive strain-at-break characteristics (reaching as great as 80% in tensile loading). Tensile testing of handsheets made from modified cellulose fibers was conducted from 50 to 90% relative humidity (RH) and from 23 to 150 °C. Strain-at-break of the handsheets ranged from 35 to 80% over this humidity and temperature range, which is significantly greater than typical cellulose-based materials. The combined effect of moisture and temperature was further investigated by dynamic mechanical thermal analysis, which was utilized to determine the glass-transition temperature of the handsheets as a function of relative humidity. Based on the tensile test results and verified by the three-dimensional (3-D) forming and simulation, a forming limit diagram (strain-based failure surface which describes and illustrates the formability of the material) for the handsheets was generated. This forming limit illustrates significant extent to which this bio-based material can be 3-D formed into advanced structures. Furthermore, temperature was identified as the best, quickest, and most controllable method of improving extensibility of this material during 3-D forming. [ABSTRACT FROM AUTHOR]

A three-dimensional model of the steam ejector heat pump for the dryer section of the paper machine was developed by applying the Computational Fluid Dynamics (CFD) technique, which provided the pressure and velocity distributions of fluid flow in heat pump. The results indicated that the fluid velocity field in heat pump has an incomplete axially symmetrical distribution. The entrainment ratio of the heat pump initially increases rapidly with the increase of the ejected steam inlet pressure and then decreases after the inlet pressure exceeds one certain value. There exists a critical value for the mixed fluid pressure under the given operating conditions. The optimal ratio of the diameter of constant area mixing section to the steam nozzle throat diameter is about 3.4 and the optimal ratio of length to diameter of constant area mixing section L/D m is 6. An optimal divergence angle of diffuser was observed under different diffuser length. There is an optimized steam nozzle position under the given operating condition where the maximum of entrainment ratio was observed. The CFD technique is found to be an efficient alternative to predict the ejector performance and the conclusions of the research can provide a beneficial reference for structural optimization design of ejector. [ABSTRACT FROM AUTHOR]

In the simulation of two-phase flow dominated by surface tension, accurate surface tension modeling is beneficial to better reproduce and understand the mechanism of interphase flow. In this paper, based on an ISPH-FVM coupling framework, three different surface tension models are implemented and tested respectively, including the generally used continuum surface force (CSF) model, the continuous surface stress (CSS) model and the height function (HF) model. In the present ISPH-FVM coupling framework, the ISPH particle approximate interpolation technique combined with a volume fraction correction scheme is employed to ensure the volume conservation in the computational domain during the information transfer between particles and grids. Meanwhile, the three surface tension models are discretized and calculated by the volume fraction defined on the FVM grid. The volume fraction of the FVM grid is obtained by approximate interpolation of ISPH particles within the grid support domain. Several benchmark cases are tested to verify the performance of three surface tension models in the ISPH-FVM coupling method. The results show that the CSF model and CSS model have less spurious currents and better robustness than HF model under the present coupling method. In addition, the CSF model and CSS model can simulate the flow regime involving complex interface topology changes more accurately than HF model. • An ISPH-FVM coupling method is developed to simulate two-phase flows. • The volume conservation is guaranteed during the information transfer. • Three surface tension models are implemented and compared under the present coupling method. • The CSF and CSS model can get relatively small spurious currents than HF model. • The CSF and CSS model perform well in predicting the complex interface topological changes. [ABSTRACT FROM AUTHOR]

The launcher recovery method known as 'In-Air Capturing' is an innovative approach where a winged rocket stage is captured mid-air by an aircraft and subsequently towed back to the launch site. To achieve this, a capturing device attached to a tether is released from the towing aircraft. This device autonomously connects the reusable launch vehicle to the aircraft, while the two vehicles are in proximity. The tether's flexible dynamics have a strong influence on the maneuverability of the capturing device. Thus, it is critical to model the dynamics of the tether to get a realistic understanding and to evaluate feasibility of the concept. However, precise modelling and control of highly flexible systems with large deformations is both challenging and computationally intensive. For engineering applications which involve closed-loop simulations, finding a trade-off between accuracy and computational effort is crucial. In this paper, the tether is modelled as a discretized chain of rigid bodies connected by rotational springs at the joints. The tether along with the capture system is integrated in a simulation model and open loop tests are performed to analyse the system characteristics. The tether properties are studied to find a suited configuration for 'In-Air Capturing'. • Multibody modelling approach for long cable like bodies with large deformation. • Capture system dynamics for the unique 'In-Air Capturing' launcher recovery concept. • Dynamic modelling for the complete capturing system including towing aircraft, capturing device and tether. • Assessment of tether properties suited for 'In-Air Capturing' with sensitivity studies. [ABSTRACT FROM AUTHOR]

Highlights: [•] A dynamic model for longitudinal vibration assisted guillotining of paper is developed. [•] Empirical model of a stack of thin paper material is identified. [•] Novel measurement procedure for determining dynamic behavior for ultrasonic assisted cutting is developed. [•] Simulated cutting forces are in agreement with the experimentally recorded cutting forces. [Copyright &y& Elsevier]

Among all public buildings, on account of their educational purpose, school buildings have a major social responsibility. Therefore energy performance in this type of building is of great importance. The overall purpose of this research is to achieve a functional benchmarking, based on the real operation conditions of school buildings, by the exploitation of the results made public, through an intensive literature survey on energy consumptions in schools. The survey was made to gather data that is relative to energy consumption in school buildings, documented in the most diverse fields and units: global energy consumption values, electrical energy consumption; fuel consumption for heating, energy data consumption of schools expressed in annual cost per unit of heated/cooled surface area ($/m 2 ) or per unit of heated/cooled volume ($/m 3 ) or, finally, as the annual cost per student ($/student). The literature was analyzed to determine if a worldwide comparison among the published data could be established. The results suggest that when attempting to determine an energy benchmark some considerations should not be forgotten: standard indoor environmental conditions (IEC) for classrooms (set-point for indoor operative temperature of 20 °C in winter and 26 °C in summer as suggested in EN 15251:2007), electrical and heating consumption values should be kept separately, different education levels usually require different energy consumption values. A good way to normalize heating energy consumption is going through a climatic adjustment based on Heating Degree Days (HDD). For an impartial data comparison, based either on an operating rating or on a simulation carried out for reference conditions, benchmark reference values should be expressed in terms of billed energy data. [ABSTRACT FROM AUTHOR]

The article describes the method of synthesis of the simulation model of pulse converters with the control system, intended for implementation in FPGA. The technique is based on the structural representation of integro-differential and algebraic equations and the method of switching breaking functions. The models you develop allow you to bring modeling time closer to real. The method is described by an example of a solar battery energy conversion channel of an automatic spacecraft power supply system. The paper considers the possibility of implementing a solar-hydrogen energy supply scheme. This concept involves the accumulation of excess energy in the form of chemical energy on board the spacecraft. [ABSTRACT FROM AUTHOR]

This paper presents the high-fidelity physical modeling of a Thrust Vector Control (TVC) system operated by Electro-Mechanical Actuators (EMAs) for Reusable Launch Vehicles (RLVs). In contrast to simplified, often linear, models, high-fidelity physical models enable a better assessment of the actual system performance and a deeper verification of the on-board software robustness against disturbances, unmodeled dynamics or degradation. This aspect is essential to enable the reusability concept as driven by long-term reliability requirements. Moreover, critical systems like Fault Detection, Isolation and Recovery (FDIR) logic, whose robustness and efficacy are often difficult to prove, can be thoroughly tested without requiring hardware experiments with eventual invasive modifications for fault injections. This work captures the whole dynamics of the EMA and TVC components, including the power drive electronics, the electrical motor, and the mechanical transmission for the EMA, as well as the mechanical properties of the engine nozzle acting as a load. The resulting differential algebraic equation system is modeled in the Modelica acausal object-oriented modeling language. An ad-hoc framework is implemented to guarantee flexibility and modularity, which allows models with different fidelity levels to be easily exchanged to achieve the simulation objectives and needed accuracy level. The impact of the different models on the closed-loop TVC dynamics is analyzed in both the frequency and time domain, and then benchmarked with a realistic RLV mission. The results show that the high-fidelity physical models provide a better understanding of the more complex effects governing the TVC dynamics and can, in turn, effectively improve its requirement definition process. • The physical modeling and simulation of an EMA-based TVC system is presented. • High-fidelity physical models help assessing TVC system control software performance. • EMA component models with incremental fidelity levels are proposed. • EMA and TVC system models are integrated in a Modelica-based framework. • Different closed-loop responses are analyzed in the frequency and time domains. [ABSTRACT FROM AUTHOR]

Discussion of paper "Numerical generation of inflow turbulence by cell perturbation technique in WRF simulation" by Singh et al. (2020). Inflow turbulence generation, Large-eddy simulation, Cell perturbation method, Atmospheric boundary layers. [Extracted from the article]

Response to discussion of paper "Numerical generation of inflow turbulence by cell perturbation technique in WRF simulation" by Munoz-Esparza et al. Inflow turbulence generation, Cell perturbation, Atmospheric boundary layers. [Extracted from the article]

This paper introduces a flexible framework to enable high-fidelity simulations of the fuel slosh dynamics for verification of the Guidance, Navigation and Control (GNC) algorithms. The sloshing phenomenon must be tackled during the control system design phase and the GNC software run and validated within appropriate simulation frameworks. Equivalent mechanical models can well approximate sloshing under specific assumptions, allowing the derivation of the multibody vehicle's equations of motion; however, while suitable for analysis and control synthesis purposes, this approach presents several limitations for implementation as a simulation model. In this work, the multibody plant embedding slosh dynamics is modeled by means of the DLR's Vertical Landing Vehicles Library (VLVLib) written using the object-oriented Modelica modeling language. The advantages of using Modelica are explored throughout the paper. Given that control synthesis, analyses and simulation campaigns are usually performed in the Matlab/Simulink environment, a core point of the proposed solution is to achieve a good synergy within the latter and the Modelica plant model with the least readaptation burden for the developer. The strategies to achieve a full integration and verification tool chain are illustrated. The potential of this approach is demonstrated via two different test cases: a lunar landing scenario of the ALINA spacecraft developed by PTS, and CALLISTO reusable rocket demonstrator. • A flexible framework to enable high-fidelity simulations of the fuel slosh dynamics for verification of the GNC algorithms is introduced. • The spacecraft model embedding the slosh dynamics is implemented exploiting Modelica language. • A GNC testing framework is obtained with the integration of the causal Simulink environment with the compiled Modelica model. • Two test cases are presented: the ALINA spacecraft lunar landing scenario and CALLISTO reusable Vertical-Takeoff–Vertical-Landing demonstrative mission. [ABSTRACT FROM AUTHOR]

Integrated geographic modelling and simulation is a computational means to improve understanding of the environment. With the development of Service Oriented Architecture (SOA) and web technologies, it is possible to conduct open, extensible integrated geographic modelling across a network in which resources can be accessed and integrated, and further distributed geographic simulations can be performed. This open web-distributed modelling and simulation approach is likely to enhance the use of existing resources and can attract diverse participants. With this approach, participants from different physical locations or domains of expertise can perform comprehensive modelling and simulation tasks collaboratively. This paper reviews past integrated modelling and simulation systems, highlighting the associated development challenges when moving to an open web-distributed system. A conceptual framework is proposed to introduce a roadmap from a system design perspective, with potential use cases provided. The four components of this conceptual framework - a set of standards, a resource sharing environment, a collaborative integrated modelling environment, and a distributed simulation environment - are also discussed in detail with the goal of advancing this emerging field. [ABSTRACT FROM AUTHOR]

Explosion is a significant threat to chemical process safety, which often occurs suddenly with a wide range of impact, resulting in catastrophic disasters. Predictions of explosion hazards are required for regional safety assessment and disaster resilience enhancement of chemical industrial parks (CIPs). This paper, therefore, aims to develop a conceptual framework for systematically analyzing explosion evolutions and quantifying the potential hazards by combining system-theoretic process analysis (STPA) method with numerical simulation. The proposed framework consists of 5 steps: (i) establishment of hierarchical safe control structures (SCSs) of important chemical processing zones in the CIP, (ii) computational fluid dynamics (CFD) modeling for potential explosion evolutions in each zone by changing the examined parameters randomly, (iii) development of a convolutional neural network (CNN) prediction model through constant self-learning of CFD pressure field data, (iv) comprehensive assessment of blast damage by incorporating the outputs of the above numerical models into existing evaluation methods, (v) identification of unsafety control actions and causes, and safety constraints for the improvement of SCSs. Provided with monitoring data, the developed analysis architecture can predict explosion process hazards and recommend appropriate safety strategies in real time. This would service the multi-level requirements for explosion prevention and protection, supporting better-informed decision-making. The paper describes the concepts and implementation process of the method as a first step. [ABSTRACT FROM AUTHOR]

This paper describes an accurate model of the Electrical Power Subsystem (EPS) of the Thermal Analysis Support and Environment Characterization Laboratory (TASEC-Lab), a university experiment developed for using in high-altitude balloon missions to measure and analyze the convection heat transfer. A Li-ion battery and two high efficient DC–DC converters have been characterized through laboratory tests and fitting to the experimental results. The developed mathematical models described in this paper are used to carry out accurate EPS simulations and are validated by comparison with the experimental data. • Design and modeling of the electrical power subsystem of a stratospheric balloon experiment. • New Li-lion battery discharging model that describes the three main parts: initial decay, linear, and exponential decay. • Formulation of a new DC/DC converter efficiency model. • Simulation and model validation of the electrical power subsystem. [ABSTRACT FROM AUTHOR]

• Two coupled parallel frameworks for shell and tube heat exchangers are proposed. • Fully three-dimensional parallel computation on both sides of the heat exchanger is realized. • One-to-one method achieves 85% parallel efficiency in 14 cores computation. • One-to-many method improves computational efficiency by about 20 times over serial in 28 cores computation. Shell and tube heat exchanger is widely used as a common type of heat exchanger. When the size and the number of heat exchanger tubes are enormous, it is difficult to use the direct modeling method for numerical simulation of heat exchangers. The simplified modeling method based on porous media utilizing user-defined function (UDF) has been widely applied. However, when the three-dimensional (3D) modeling is required on the tube side, the parallelization problem still restricts the computational efficiency of numerical simulation. In this paper, a one-to-one parallel method was first developed to solve the problem of coupled parameter transfer between the primary and secondary sides in the parallel framework, which was tested to achieve a parallel efficiency of 85% under 14 cores. However, the method acquires complicated data transfer between nodes, large memory occupation, and the modeling of the tube side is different from the actual structure under certain circumstances. To solve the problems, a one-to-many parallel method is proposed, and the computational efficiency is tested to be enhanced by about 20 times under 28 cores compared with single core, with a parallel efficiency of 70%. The two methods proposed in this paper are of great significance to the parallel transformation of the future 3D full-size code for shell and tube heat exchangers development and the calculation efficiency improvement. [ABSTRACT FROM AUTHOR]

The paper provides an overview of the radiation protection challenges and the advanced simulation techniques used to study and plan complex interventions in radiation areas at CERN, particularly with regard to the Large Hadron Collider. The operational radiation protection aspects are supported by state of the art simulations by means of the FLUKA Monte Carlo code and estimates obtained via several tools, used within the CERN Radiation Protection group, such as ActiWiz, SESAME, and the Fluence Conversion Coefficients (FCC) method which extend the built-in FLUKA capabilities. The paper covers the general Radiation Protection principles and rules in force at CERN, the simulation tools/techniques used to fulfill operational tasks and predictive studies, and a set of case studies covering relevant applications at the Large Hadron Collider machine and experiments. • Advanced and reliable simulation tools are essential in modern Radiation Protection. • FLUKA is widely used at CERN for radiation protection studies at the LHC complex. • Simulation tools such as SESAME, FCC and ActiWiz extend FLUKA built-in capabilities. • RP studies of the upgrade of the LHC are mainly based on advanced simulation tools. • Real-case applications and examples are provided in the paper. [ABSTRACT FROM AUTHOR]

A system of diffusion–reaction equations coupled with a dissolution–precipitation model is discussed in this paper. We start by introducing a microscale model together with its homogenized version. In the present paper, we first derive the corrector results to justify the obtained theoretical results. Furthermore, we perform the numerical simulations to compare the outcome of the effective (homogenized) model with the original heterogeneous microscale model. [ABSTRACT FROM AUTHOR]

Torsional nano-scanners have a variety of applications in nano/micro-electro-mechanical systems. In this paper, two- and three-dimensional numerical solutions based on the lattice Boltzmann are proposed for simulating the dynamic behavior of an electromechanical torsional nano-scanner. The complete governing equations are modified based on the couple stress theory and developed by considering the effect of the Casimir force. Furthermore, the physics of the system is extended by considering the effects of dissolved electric agents on the dynamic performance of the nano-scanner. The passive/active electrolyte flow behavior with the moving solid boundary is described and simulated using Nernst-Plank-Poisson compensation of the electrolyte flow. The proposed numerical results are validated by comparing them with those available in the literature. Finally, the influence of scale dependency and Casimir force on the nano-scanner's dynamic performance and pull-in instability are investigated. Also, as torsional nano-scanners might be immersed in ionic media, the impact of ionic concentration on the pull-in voltage of a nano-scanner is investigated. The obtained results demonstrate that increasing the ionic concentration reduces the instability voltage of the nano-scanner considerably. [ABSTRACT FROM AUTHOR]

Solar-hydrogen energy systems for spacecraft reliably provide energy for carrying out various kinds of unscheduled work on board and for eliminating emergency situations. Surplus energy is constantly accumulated on board in the form of the chemical energy of cryogenic hydrogen. The article presents too the result of the development of a solar-hydrogen power supply system for spacecraft, the onboard network of which provides slow and fast processes. The paper presents too pulsed and continuous models of voltage converters of the electrical power system of automatic spacecraft. It is proved on the simulation basis that the deviation of frequency characteristics of continuous models from pulse ones is insignificant (not more than 2%), while the use of continuous models to study both frequency and time characteristics of the converter allows us to reduce the simulation time tenfold. [ABSTRACT FROM AUTHOR]

In this paper, a fractional nonlinear control strategy based on the nested saturations technique and the Caputo-Fabrizio derivative for a quadrotor aircraft, to maintain desired position and orientation in stationary flight and trajectory tracking tasks, is proposed and developed. In addition, the dynamic model is obtained by using the Euler–Lagrange formulation, and then it is generalized to an arbitrary order through the Caputo-Fabrizio derivative. The traditional nonlinear control based on the nested saturation technique is also developed and implemented on the quadrotor for comparison purposes between both control schemes. Numerical simulations demonstrated the superiority of the proposed control strategy for stabilizing the quadrotor at hover and reaching the desired position and orientation, over its integer-order counterpart. In addition, three additional desired trajectories are considered, keeping the same gains and orders, to demonstrate the robustness of the proposed control scheme under different operating conditions. In this sense, our controller presents significant performance improvements, which were validated through system simulations. Our proposed control system and its traditional counterpart were tuned experimentally using the response of the system to a desired trajectory. [ABSTRACT FROM AUTHOR]

• A detailed dynamic simulation model for a Molten Salt Solar Tower system is implemented in Modelica®. • A two-phase flow model is developed for filling and drainage simulations of a molten salt receiver system. • In a discretized absorber tube model maximum values of local fluid and tube wall temperatures are approximated. • Startup and shutdown simulation including the entirely controlled receiver system are conducted. • Validation with CFD simulation is carried out. In order to realistically predict and optimize the actual performance of a concentrating solar power (CSP) plant sophisticated simulation models and methods are required. This paper presents a detailed dynamic simulation model for a Molten Salt Solar Tower (MST) system, which is capable of simulating transient operation including detailed startup and shutdown procedures including drainage and refill. For appropriate representation of the transient behavior of the receiver as well as replication of local bulk and surface temperatures a discretized receiver model based on a novel homogeneous two-phase (2P) flow modelling approach is implemented in Modelica Dymola®. This allows for reasonable representation of the very different hydraulic and thermal properties of molten salt versus air as well as the transition between both. This dynamic 2P receiver model is embedded in a comprehensive one-dimensional model of a commercial scale MST system and coupled with a transient receiver flux density distribution from raytracing based heliostat field simulation. This enables for detailed process prediction with reasonable computational effort, while providing data such as local salt film and wall temperatures, realistic control behavior as well as net performance of the overall system. Besides a model description, this paper presents some results of a validation as well as the simulation of a complete startup procedure. Finally, a study on numerical simulation performance and grid dependencies is presented and discussed. [ABSTRACT FROM AUTHOR]

Assembly accuracy analysis plays a very important role in verifying whether the design scheme of geometric accuracy in the product design stage can meet the functional requirements of mechanical product. Form deviations, position and orientation deviation are inevitable in manufactured parts, and must be considered during assembly accuracy analysis. With regard to the representation of form deviations, it is verified that skin model shapes are effective. However, the existing simulation approaches of skin model shapes for cylindrical parts are mainly based on gaussian random field, without considering the spatial distribution characteristics of form deviations in dealing with the relationship between geometrical and dimensional deviation for cylindrical parts. Especially, when considering local surface deformations of cylindrical mating surfaces generated during the assembly process, the form deviations with different distribution characteristics leads to different contact deformation, which may have further influence on assembly accuracy analysis of cylindrical parts. To address above problems, this paper proposes a simulation method of skin model shapes of cylindrical parts based on Non-Gaussian random field considering the spatial distribution characteristics of form deviations, and the local surface deformations are analyzed with a boundary element method. Based on above, the relative positioning deviation of cylindrical mating surfaces is obtained considering the influence of form deviations and local surface deformations. Finally, the effectiveness of the proposed method is verified with case studies. Specifically, the results of case study reveal that the influences of form deviations considering spatial distribution characteristics and local surface deformations cannot be ignored for assembly accuracy analysis of cylindrical parts. In addition, for the relative positioning deviation of cylindrical mating surfaces for loose fit, the influence of local surface deformations on translational deviations along the x-axis and y-axis is greater than that on rotational deviations around the x-axis and y-axis. • A skin modeling method of cylindrical parts is proposed based on Non-Gaussian random field. • Spatial distribution characteristics of form deviations and local surface deformations are considered. • CG-DC-FFT method is adopted to solve local surface deformations of cylindrical mating surfaces. • Form deviations of cylindrical mating surfaces have influence on assembly accuracy analysis. • Local surface deformations of cylindrical mating surfaces have influence on assembly accuracy analysis. [ABSTRACT FROM AUTHOR]

• A new reliability method combining relevance vector machine and subset simulation importance sampling is proposed. • The ability of surrogate model-based subset simulation importance sampling to handle multiple failure mode problems is achieved. • An efficient update strategy is employed to improve the prediction accuracy of relevance vector machine and avoid unnecessary iterations. • The proposed method improves computational efficiency while ensuring the accuracy of the result. Evaluating the failure probability of engineering structures involving implicit performance functions generally requires time-consuming finite element simulations. The computational effort is usually unbearable, especially for small failure probability. This paper proposes a new reliability analysis method combining relevance vector machine and subset simulation importance sampling, which guarantees the accuracy of results and improves the computational efficiency. In this method, relevance vector machine is first applied to approximate relatively coarse limit states. Then, subset simulation importance sampling is executed based on the constructed relevance vector machine. To improve the prediction accuracy, samples from first and last level are used to refine relevance vector machine. Since only the samples of last level are involved in the calculation of the failure probability, and the updated relevance vector machine has a very high prediction accuracy for the samples of last level, the obtained failure probability is extremely accurate. In addition, the samples are predicted by the well-constructed relevance vector machine rather than evaluated with real performance functions, which drastically decreases the calculation time. To reduce redundant iterations in the update process, a novel learning function based on the current design of experiment position and a stopping condition based on error estimation of reliability prediction are employed. Furthermore, the K-means clustering algorithm is utilized to implement the ability of surrogate model-based subset simulation importance sampling to handle multiple failure mode problems. The efficiency and accuracy of the proposed method are verified by four examples involving different types of features. [ABSTRACT FROM AUTHOR]

Photovoltaic (PV) systems have become an integral and widespread part of renewable energy generation. In combination with energy storage, they offer a variety of advantages such as increased self-sufficiency or improved grid stability. However, geographic location, subsidies, energy tariffs, size of PV panels and battery, and other factors significantly influence the overall performance and profitability of the system. Solving this complex task of system design and component dimensioning is not easy. The diversity and multitude of parameters therefore usually requires the help of, more or less complex, computer simulations. This led and still leads to a high publication activity on techno-economic and other optimizations for such systems. However, the operating strategies and component models are often oversimplified, leading to results with significant errors. The goal of this paper is to provide in-depth insight into component modeling and parametrization for PV module, battery energy storage, and inverter, as well as giving suggestions on appropriate control strategies. The focus lies on the description of suitable simple-but-accurate models and their parametrization. In order to avoid the effort of having to conduct measurements for component characterization, an approach relying on values presented in product data sheets is considered. Furthermore, the effects of model simplifications, as they are found in many publications, are shown. Finally, the importance of an uncertainty analysis for the entire simulation is discussed in order to gain insight into the accuracy of the calculated simulation results and their dependency on model- and input-parameters. • Photovoltaic system modeling/simulation. • Component modeling for PV module, battery energy storage and inverter. • Suitable simple-but-accurate models and their parametrization • Characterization relying on product data sheets with minimal informations. [ABSTRACT FROM AUTHOR]

• Derive trajectory and vibration equations in fractal dimension. • The designed simulation surface has self-affinity and directionality. • Reduction of Sa and Sq errors in simulation models. • The study can provide simulation data support for machine vision measurement. The grinding surface's 3-D topography has self-affinity. To more accurately simulate this characteristic, this paper proposes for the first time to construct a grinding surface simulation model based on fractional derivatives, including: utilizing the Weierstrass-Mandelbrot function to simulate the point cloud of the grinding wheel surface; further deriving the trajectory equation based on the He's fractal derivative; the semi-inverse method is employed to construct the fractional-order variational principle of the vibration equation. Experiments show that the simulation model designed in this paper can predict the surface height more accurately, and is better than the traditional model in the calculation of roughness parameters Sa and Sq. The model is helpful to thoroughly understand the formation mechanism of grinding surface topography, and provides simulation data guidance for machine vision inspection of grinding surface in micron scale. [ABSTRACT FROM AUTHOR]

Emergency response environments in which the crisis occurs include many homogenous and heterogeneous entities, e.g., organizations and persons. These entities need to collaborate to address a crisis. However, most of the time, the organizations that are involved in a crisis suffer from communication and coordination problems. This may cause unfair resource distribution. To mitigate the problem, there is a pressing need to construct models of emergency response environments and simulate the coordination strategies proactively, before the onset of any crisis. This paper highlights the complexity of the system formed by interacting organizations during a crisis and the difficulty in programming for the simulation of such complex systems. To cope with this issue, this paper presents an executable domain-specific modeling language called CoorERE. The language facilitates modeling emergency response environments for the simulation of one of the most common coordination strategies, i.e., auction-based coordination strategies in crisis response. CoorERE is used for the graphical modeling of emergency response environments and simulation of both inter and intra-organizational auction-based coordination strategies. The paper presents two case studies with different complexities to show the applicability of CoorERE. An empirical study is conducted to compare CoorERE with MDD4ABMS, which is one of the most recent tools for modeling and simulation of multi-agent systems. The evaluation includes both objective and subjective assessments. The objective assessment considers the development effort required for modeling a complete case study, while the subjective assessment compares the tools in terms of satisfying modeling method requirements and quality metrics such as usability, productivity, and expressiveness. The results of the evaluation indicate that CoorERE reduces the development effort by about 47%. In terms of quality metrics, CoorERE obtained higher scores than MDD4ABMS for all the measurements considered, indicating its superior usability, productivity, and expressiveness. [ABSTRACT FROM AUTHOR]

In this paper, we address modelling and simulation of dynamics involved in docking of large marine vessels with aid of tugboats, with the aim of providing a tool for improved design of control algorithms for autonomous docking operations. Mathematical models of the docking vessel and tugboats in 3DOF are derived, with a special focus on realistic interactions through towline, contact and friction forces with stick–slip dynamics and time delays, which are typically not considered in previous publications on the topic. We also present the implementation of the developed models in the first step towards a Simulink simulator in which considers the special case of tugboat-assisted docking operations in the Narvik harbour. The developed simulator is available on GitHub (see Ørke et al. (2023)) and encompasses model dynamics, tugboat control and vessel control and guidance, although the scope of this paper is model dynamics. We present simulation results that show that we are indeed able to capture interaction dynamics in a realistic way. Finally, we include a discussion of our results and some ideas for further development, as well as some concluding remarks. [Display omitted] • Mathematical modelling of docking vessel and tugboats in 3DOF. • Modelling of interaction forces in pushing/pulling operations. • Model implementation in Simulink-developed simulator. • Simulation and discussion of interaction forces, and ideas for future work. [ABSTRACT FROM AUTHOR]

Second-order macroscopic continuum models have been constantly improving for decades to reproduce the empirical observations. Recently, a series of experimental studies have suggested that the stochastic factors contribute significantly to destabilizing traffic flow. Nevertheless, the traffic flow stability of the stochastic second-order macroscopic continuum model has not received the attention it deserves in past studies. More importantly, we have found that the destabilizing aspect of stochasticity is still not correctly validated in the existing theoretical stability analysis. In this paper, we analytically study the impact of stochasticity on traffic flow stability for a general stochastic second-order macroscopic model by using the direct Lyapunov method. Numerical simulations have been carried out for different typical stochastic second-order macroscopic models. Our analytical stability analysis has been validated, and our methodology has been proved more efficient. Our study has theoretically revealed that the presence of stochasticity has a destabilizing effect in usual stochastic macroscopic models. • Stability condition of a general stochastic second-order macroscopic continuum model. • The Lyapunov method outperforms the eigenvalue method. • The stochastic macroscopic models respond differently to the presence of stochasticity. • The presence of stochasticity has a destabilizing effect in usual stochastic macroscopic models. [ABSTRACT FROM AUTHOR]

The computational fabrication community is developing an increasing interest in the use of patterned surfaces, which can be designed to show ornamental and unconventional aesthetics or to perform as a proper structural material with a wide range of features. Geometrically designing and controlling the deformation capabilities of these patterns in response to external stimuli is a complex task due to the large number of variables involved. This paper introduces a method for generating sets of tileable and exchangeable flat patterns as well as a model-reduction strategy that enables their mechanical simulation at interactive rates. This method is included in a design pipeline that aims to turn any general flat surface into a pattern tessellation, which is able to deform under a given loading scenario. To validate our approach, we apply it to different contexts, including real-scale 3D printed specimens, for which we compare our results with the ones provided by a ground-truth solver. [Display omitted] • Patterns are interesting from a visual and a mechanical perspective. • Their computational design is complex and an intriguing task. • We provide an efficient simulation model with our generated flat patterns. • Pipeline for direct design of tiled patterns' assemblies. • Design exploration with an interactive tool that manages geometry and loads. [ABSTRACT FROM AUTHOR]

With the widespread applications of sintered NdFeB, the impact-prone scenarios are often encountered. Such impacts will cause magnetic disorder inside the magnet and further demagnetization. At present, research on impact-induced demagnetization of sintered NdFeB mostly focuses on experimental investigations, lacking clear theoretical expressions and visual reproduction of the microscopic demagnetization process. To end this, this paper uses the impact-induced demagnetization experiment, theoretical expression, and micromagnetic simulation to reveal and quantify the demagnetization behavior of NdFeB. An impact-induced demagnetization experimental platform capable of producing corresponding load amplitudes is first established. The experimental results demonstrate the existence of reversible and irreversible demagnetization of NdFeB under impact. A magneto-mechanical constitutive model for sintered NdFeB considering stress history is further developed using the principle of thermodynamic, pinning effect and proximity effect. The residual magnetization intensity between the numerical simulation and the experimental results have good agreement. Finally, the demagnetization behavior of the magnet is visually displayed through the micromagnetic simulation. Employing the LLG equation and kinematic equations for elastic waves, a set of magnetization dynamics equations is established to analyze impact-induced demagnetization characteristics in sintered NdFeB. These results will provide the reference for the application of NdFeB in impact environment. • Carry out impact-induced demagnetization experiment of sintered NdFeB. • Obtain the magneto-mechanical constitutive demagnetization model of sintered NdFeB. • Reveal the demagnetization mechanism of sintered NdFeB by micromagnetic simulation. • Verify the constitutive model through the impact-induced demagnetization experiment and micromagnetic simulation results. [ABSTRACT FROM AUTHOR]

Sampling in control applications is increasingly done non-equidistantly in time. This includes applications in motion control, networked control, resource-aware control, and event-based control. Some of these applications, like the ones where displacement is tracked using incremental encoders, are driven by signals that are only measured when their values cross fixed thresholds in the amplitude domain. This paper introduces a non-parametric estimator of the impulse response and transfer function of continuous-time systems based on such amplitude-equidistant sampling strategy, known as Lebesgue sampling. To this end, kernel methods are developed to formulate an algorithm that adequately takes into account the bounded output uncertainty between the event timestamps, which ultimately leads to more accurate models and more efficient output sampling compared to the equidistantly-sampled kernel-based approach. The efficacy of our proposed method is demonstrated through a mass–spring damper example with encoder measurements and extensive Monte Carlo simulation studies on system benchmarks. [ABSTRACT FROM AUTHOR]

Data-driven three-dimensional (3D) mineral prospectivity modeling (MPM) employs diverse 3D exploration indicators to express geological architecture and associated characteristics in ore systems. The integration of 3D geological models with 3D computational simulation data enhances the effectiveness of 3D MPM in representing the geological architecture and its coupled geodynamic processes that govern mineralization. Despite variations in modality (i.e., data source, representation, and information abstraction levels) between geological models and simulation data, the cross-modal gap between these two types of data remains underexplored in 3D MPM. This paper presents a novel 3D MPM approach that robustly fuses multimodal information from geological models and simulation data. Acknowledging the coupled and correlated nature of geological architectures and geodynamic processes, a joint fusion strategy is employed, aligning information from both modalities by enforcing their correlation. A joint fusion neural network is devised to extract maximally correlated features from geological models and simulation data, fusing them in a cross-modality feature space. Specifically, correlation analysis (CCA) regularization is utilized to maximize the correlation between features of the two modalities, guiding the network to learn coordinated and joint fused features associated with mineralization. This results in a more effective 3D mineral prospectivity model that harnesses the strengths from both modalities for mineral exploration targeting. The proposed method is evaluated in a case study of the world-class Jiaojia gold deposit, NE China. Extensive experiments were carried out to compare the proposed method with state-of-the-art methods, methods using unimodal data, and variants without CCA regularization. Results demonstrate the superior performance of the proposed method in terms of prediction accuracy and targeting efficacy, highlighting the importance of CCA regularization in enhancing predictive power in 3D MPM. • Casting 3D mineral prospectivity modeling (MPM) as a deep multimodal fusion problem. • Joint fusion network for integrating features of 3D geological models and simulation data. • Canonical correlation analysis regularization to guide network fusion of the cross-modal gap. • Maximizing the correlation of multimodal information boosts the performance of 3D MPM. [ABSTRACT FROM AUTHOR]

Prior research lacks understanding about how collaborative arrangements and network structures influence innovation outcomes in platform-based ecosystems. This paper addresses this gap by using an NK simulation model to investigate the impacts of different collaboration patterns and network structures on innovation performance. The NK simulation approach overcomes the shortcomings of empirical methods and enables examining the dynamic impacts. The results reveal that the "special platform + generic complementor" pattern leads to the highest innovation output. The impact of component correlations on the innovation performance follows an inverted U-shape. The small world network structure promotes innovation versus regular or random networks. The results provide novel theoretical insights into strategically configuring platform partnerships and network connections to optimize innovation. The findings offer practical guidance for firms to choose beneficial collaboration pattern and design proper network structure. [ABSTRACT FROM AUTHOR]

This paper proposes 1) a new hybrid analysis technique by integrating a data-driven method with a physics-based technique to perform nonlinear analysis of steel structural systems under seismic loading, 2) two component-based data-driven models (PI-SINDy and DPI-SINDy) for predicting the nonlinear hysteretic response of steel seismic fuses with and without hysteretic degradation. The proposed hybrid data-driven and physics-based simulation (HyDPS) technique offers an efficient approach for seismic analysis of structures and is expected to address the challenges associated with computational cost and modeling uncertainties inherent in physics-based numerical simulations. In this technique, the well-understood components of the structure modeled numerically are combined with the critical components of the structure simulated using one of the data-driven models developed in this study. The proposed data-driven models were trained using experimental and numerical hysteresis data. The results show that these data-driven models can accurately and efficiently predict the nonlinear hysteretic response of steel structural components with and without degradation. Furthermore, the performance of the HyDPS technique powered by the PI-SINDy model is verified in the presence of noise using response history analyses performed on a steel buckling-restrained braced frame. • Proposed a hybrid seismic analysis technique for steel structures combining data-driven and physics-based models. • Developed two sparse regression-based data-driven models for simulating steel structures with/without degradation. • Utilized a dimensionality reduction algorithm to enhance the efficiency of the data-driven model with degradation. • Validated the data-driven models and hybrid technique with experimental and synthetic numerical data. [ABSTRACT FROM AUTHOR]

In this paper, a novel numerical simulation approach based on the finite element method for dynamically modeling the excavation process of shield tunneling is proposed, with the shield-ground interactions well captured. This method is capable of mimicking the alternating modes of advancing and stopping of a shield boring machine during underground construction, with the important effects of the cutterhead rotation and slurry support pressure considered. Under the cutting action, the soil at the excavation face would experience irreversible deformation and damage, such that additional support needs to be provided by the cutterhead blades and slurry to maintain stability. The impacts of key construction parameters are examined, including cutterhead rotary speed, advance rate, and slurry support pressure, on shield tunneling operations and ground responses. The numerical model is rigorously validated against physical model experiments. This work provides useful insights into the mechanistic processes in the stratum during shield tunneling, including the spatiotemporal evolution of ground deformation patterns and stress redistributions. The results offer valuable guidance for optimizing shield tunneling operations and enhancing tunneling safety and efficiency. [ABSTRACT FROM AUTHOR]

This paper aims to improve existing models for drag, lift, and pitching torque coefficients of cylindrical disc particles with a wider range of aspect ratios and particle Reynolds numbers. The full body-fitted direct numerical simulations (DNS) are carried out for three-dimensional flow past cylindrical discs in order to quantify the coefficients at aspect ratios from 0.2 to 0.6, incidence angles from 0°to 90°, and Reynolds numbers from 0.1 to 300. The CFD results are validated against the aerodynamic coefficients of both spherical and non-spherical particles presented in the literature. A full set of new correlations for the coefficients, dependent on aspect ratio, incidence angle, and Reynolds number, is further derived according to the CFD predicted data. The results show that the new correlations have a promising performance for the disc particles considered in this study. [Display omitted] • CFD simulations are performed for drag, lift, and pitching torque coefficients. • A complete set of correlations for C D , C L , and C T is proposed. • Proposed correlations work well outside the Stokes regime. • The correlation predictions agree with the CFD simulations. [ABSTRACT FROM AUTHOR]

This paper proposes rigid-body modelling and identification procedures for long-reach dual-arm manipulators in a cable-suspended pendulum configuration. The proposed model relies on a virtually constrained open kinematic chain and lends itself to be simulated through the most commonly used robotic simulators without explicitly account for the cables constraints and flexibility. Moreover, a dynamic parameters identification procedure is devised to improve the simulation model fidelity and reduce the sim-to-real gap for controllers deployment. We show the capability of our model to handle different cable configurations and suspension mechanisms by customising it for two representative cable-suspended dual-arm manipulation systems: the LiCAS arms suspended by a drone and the CRANEbot system, featuring two Pilz arms suspended by a crane. The identified dynamic models are validated by comparing their evolution with data acquired from the real systems showing a high (between 91.3% to 99.4%) correlation of the response signals. In a comparison performed with baseline pendulum models, our model increases the simulation accuracy from 64.4% to 85.9%. The simulation environment and the related controllers are released as open-source code. • Cable-suspended long-reach manipulators perform hazardous inspection and maintenance. • Accurate simulation and control development for cable-suspended robots is crucial. • Simplified dynamic model can be readily integratable into standard simulators. • Identification procedure to reduce sim-to-real gap and develop model-based controls. [ABSTRACT FROM AUTHOR]

• A three-dimensionally mesoscale concrete was geometrically reconstructed to reflect its heterogeneity. • A mesoscale model for sulfate-induced evolution of chemo-mechanical behavior of concrete was developed. • Chemo-mechanical response of concrete from sulfate diffusion to damage failure was numerically simulated. This paper aims at numerical description on the time-varying chemo-mechanical behavior of concrete served in sulfate-rich environments. For this purpose, a three-dimensionally (3-D) mesoscale model was developed to investigate the chemo-mechanical damage evolution of concrete under external sulfate attack (ESA). Firstly, a geometrical reconstruction of 3-D concrete at meso scale was carried out to reflect its material heterogeneity, while the mechanical property of every composition in mesoscale concrete was quantitatively characterized; Secondly, the diffusion and reaction of sulfates in concrete were modelled, while its induced expansion deformation and damage evolution of CM matrix were formulated; Finally, by numerical implementation in ABAQUS, these developed models were used to numerically simulate the space–time distributions of sulfate and ettringite concentrations, expansive deformation, cracking damage, mechanical performance and failure mode of concrete, and results from numerical simulation were consistent with the experimental observations. Consequently, the developed model can describe time-varying chemo-mechanical behavior of concrete, and it is beneficial for the performance evaluation and life prediction of concrete structures in sulfate environments. [ABSTRACT FROM AUTHOR]

The aircraft assembly system is highly complex involving different stakeholders from multiple domains. The design of such a system requires comprehensive consideration of various industrial scenarios aiming to optimize key performance indicators. Traditional design methods heavily rely on domain expert knowledge using documents to define assembly solutions which are later verified through simulations. However, these document-centric approaches cannot provide graphical notations for engineers to efficiently understand the entire assembly process. Moreover, it is difficult to analyze the performance of the designed assembly processes using simulations since the simulation models have to be developed based on the documents manually rather than be generated automatically from the design models. In this paper, a semantic-driven approach is proposed to support aircraft assembly process formalism and performance analysis. First, meta-models of aircraft assembly processes are developed based on SysML and discrete-event simulation models using a semantic modeling language named KARMA. Then an application ontology is defined for generating semantic models from KARMA architecture models to capture domain knowledge, system requirements and simulation model information of the aircraft assembly process. A model transformer is developed to transform the KARMA models to discrete-event simulation models based on the application ontology. Then the generated simulation models are executed to obtain the simulation results for verifying the designed assembly process. Finally, the obtained simulation results are used to support decision-making of selecting the optimal aircraft assembly process. A case study is conducted to verify the proposed method. [ABSTRACT FROM AUTHOR]

The South African sunflower industry is considering transferring to a quality-based marketing system driven by an incentive. However, the ability of silos to offer necessary segregation services is critical in such a transition (Baker et al., 1997) and the silo industry is concerned about the negative impact segregation could have on operations and finances. This paper proposes a multi-method simulation approach to quantify the impact of quality-based segregation and sunflower farmer response to the incentive on silo bin utilisation and the ability of the silo to store contents of arriving trucks (service level). A combination of agent-based simulation, discrete event simulation and Bayesian network sampling is used to capture system behaviour where data is scarce. Therefore, in this study, a mixed methods ABM and DES model is implemented in a new environment: a grade-based segregation problem in the South African silo industry. Several scenarios are modelled to cross-validate methods and to tease out the impact of farmer response on the results. The model is applied to a case study silo complex to test the concept. Results obtained for the case study silo show a significant negative impact on costs due to lower service levels and bin utilisation, incurring relocation and opportunity costs. Overall, this study highlights that it is necessary to consider the impact that sunflower segregation could have on each unique silo complex and provides a method to quantify the stated impact. • A model is developed to analyse the impact of quality-based sunflower segregation on a silo. • An agent-based model is used to solve a silo segregation problem within a new environment: the South African context. • An expert-driven Bayesian network is used to overcome a data scarcity constraint. • For a case study silo, a 6%–11% reduction in financial performance was found relative to the base case. [ABSTRACT FROM AUTHOR]

This paper investigates the dynamic behavior of a Van der Pol oscillator (used as an archetypal self-sustained oscillator) coupled to a bistable nonlinear energy sink (BNES). We first show using numerical simulations that this system can undergo a multitude of motions including different types of periodic regimes and so-called strongly modulated responses (SMR) as well as chaotic regimes. We also show that a BNES can be much more efficient than a classical cubic NES but this is not robust since a little perturbation can switch the system from harmless to harmful situations. However, even in the most unfavorable cases, it is possible to find a set of parameters for which the BNES performs better than the NES. A multiple time scales approach is then addressed to analyze the system. In this context, we show that the so-called Multiple Scale/Harmonic Balance Method (MSHBM) must be modified (compared to its usual use) to consider the specific feature of the BNES, i.e., that it can have a nonzero-mean oscillating motion. This allows us to derive a so-called amplitude-phase modulation dynamics (APMD) which can reproduce the complex behavior of the initial system. Because of the presence of a small perturbation parameter (i.e., the mass ratio between the BNES and the VdP oscillator), the APMD is governed by two different time scales. More precisely, it appears as a (3,1)-fast–slow system whose motion is constituted in a succession of slow and fast epochs. Founding a (3,1)-fast–slow APMD is interesting since that implies a more complex dynamics than in the case of a classic NES whose APMD is only (2,1)-fast–slow. A fast–slow analysis is finally conducted within the framework of the geometric singular perturbation theory. From the computation of the so-called critical manifold and the analytical expressions of the APMD fixed points, a global stability analysis is performed. This enables us to interpret a certain number of regimes observed on numerical simulations of the initial system. • A Van der Pol oscillator is coupled to a Bistable Nonlinear Energy Sinks is studied. • The so-called MSHBM is modified to consider specific features of the BNES. • The obtained amplitude-phase modulation dynamics (APMD) is a (3,1)-fast–slow system. • Fast–slow analysis of the APMD is performed. • This enables to interpret a certain number of regimes observed on numerical simulations. [ABSTRACT FROM AUTHOR]

Blistering is a unique failure form of plate fuel elements. During the long-term operation of the plate fuel element with dispersed fuel, the phenomenon of the local blister on the cladding surface caused by the accumulation of fission gas may occur. This phenomenon will not only affect the flow and heat transfer of coolant in the blister channel but also lead to a local high void fraction on the heating wall, and make the boiling crisis occur early. The forms and distributions of blisters on the cladding surface may be various under different conditions. At present, there are few reports on the distribution of void fraction in the blister channel under subcooled boiling conditions. However, CHF, which is one of the core thermal design criteria, is closely related to the distribution of void fraction. So, in this paper, the void fraction distribution in narrow rectangular channels with different blister heights and forms was studied by using the numerical simulation method with the Euler-Euler model and the modified RPI model. The calculation results showed that the void fraction at the back end of the blister area will have a local maximum, and the backflow of fluid at the back end of the blister is the main reason for the high void fraction. In addition, as the blister height increased, the local maximum value would also increase. When the blister height exceeded 1.5 mm, the local maximum void fraction would exceed 0.82, which would lead to a localized boiling crisis on the cladding surface. Under the same blister area and blister height conditions, multiple blisters were more likely to have multiple peak void fraction points than a single pillow blister. At the same location, the peak void fraction of blisters on both sides of the heating wall was higher than that on one side, and a boiling crisis might occur on both sides of the heating wall. [ABSTRACT FROM AUTHOR]

Public transport in urban and suburban areas is not always able to meet population's need of accessibility to jobs, education, health and other opportunities in terms of routes and frequencies; therefore, those who do not own a private vehicle, or who cannot afford individual public transport (e.g. taxis), are often in a condition of social exclusion. Taking advantages of new ICT tools and facilities, Demand Responsive Shared Transport (DRST) services can provide "on demand" transport gathering ride bookings of different users and routing a fleet of vehicles to satisfy passengers' needs while minimizing the cost for the operator. In this paper, different DRST service configurations are compared to taxi services to investigate their economic attractiveness and sustainability. This is done by using an agent-based simulation model applied to the case of Ragusa (Italy), a city with poor public transport supply, where an innovative DRST service has already been experimented. A set of 50 different scenarios has been simulated, by varying the numbers of vehicles and seat capacity, and considering different demand rates and route choice strategies of the vehicles. Results are analyzed according to different key performance indicators, mainly showing that the DRST system is more advantageous than taxis when dealing with higher demand rates. On the other hand, the efficiency of the DRST system is rather limited compared to taxis in the case of low transport demand and fleets with a small number of vehicles. Between high and low demand there is a balance between the taxi and the DRST systems, where one should deepen the analysis to identify optimal operational parameters. These results pave the way for further analyses to help the planning and design of intermediate transport services like DRST, which are able to bridge the gap between collective and individual transport in urban and suburban areas. • Demand Responsive Shared Transport (DRST) are new emerging mobility services. • DRST may contribute to improve accessibility and social inclusion. • In this paper DRST are compared to taxis using agent-based simulations. • The case study is a small Italian city (Ragusa) where DRST has been experimented. • Results show the optimal range of implementation of the two systems. [ABSTRACT FROM AUTHOR]

The increase in the number of vehicles on roads has compounded the difficulty in parking them when people go out for movies, shopping, theatre, etc. Thus, this paper proposes smart parking system. The reservation of the parking slots can be made using this proposed smart parking system. Unlike the methods proposed in the existing research, the system proposed in this paper divides the parking area into 3 parts. One for conventional parking, one for vehicles with reservation and the other for the vehicles with and without reservation. Learning automata is used in the proposed system to determine the percentage of the parking area for conventional parking. In general, the proportionate of the slots for reserved parking, conventional parking and common slots need to be assumed. Learning Automata helps in determining this proportionate optimally. The AES-256 encryption algorithm is used to provide security for the details provided by the user during reservation process. Goodput value is maintained for each vehicle which increases or decreases the chances of getting a reservation. The time limit for the reservation of the parking slot is also maintained after which the reservation gets cancelled automatically. Markov Model is used to represent the system. The performance of the proposed algorithm, Learning Automata and Reservation based Secure Smart Parking System (LA-RSSPS) is simulated and evaluated in terms of average waiting time, search time, the probability with which the vehicles do not get parking slot when they do not have reservation and the probability with which the vehicles do not get reservation and is compared with ProNet and iERS. Results have shown that our scheme preforms better than the ProNet and iERS competing schemes. The comparison of analytical and simulations results are also presented. [ABSTRACT FROM AUTHOR]

This paper presents a critical advancement in Building Energy Modeling (BEM) through an empirical validation approach using a high-quality dataset from a multizone commercial office building in Oak Ridge, TN, USA. BEM is widely utilized in diverse construction applications, but its effectiveness relies on the accuracy of its predictions. The study focuses on empirical validation of input parameters in BEM, including building envelope data, infiltration modeling, and rooftop unit system performance curves. The validation of simulation input parameters leads to substantial improvements in the accuracy of simulation results. Notable both NMBE and cv (RMSE) values are reduced by 0.5 % for indoor air temperature and 17 % for indoor air relative humidity compared to the previous model. At the system level, both NMBE and cv (RMSE) values are reduced by 2 % for fan energy consumption and 4 % for cooling energy consumption, compared to the previous model. A literature review highlights a significant gap in empirical validation studies, which predominantly concentrate on either component-level or whole building validation. Furthermore, many studies employ simplified setups that may not faithfully represent the complexities of multizone commercial buildings. This paper distinguishes itself by emphasizing the critical importance of component-level input parameter validation. It underlines the need to validate data related to building envelope components and HVAC system performance curves, resulting in more accurate simulation outcomes. The utilization of actual multizone commercial building data enhances the study's practical relevance. In summary, this research underscores the pivotal role of input parameter validation in enhancing the accuracy and reliability of BEM. • The EnergyPlus simulation model input parameters have been empirically validated. • Building envelope input parameters have been evaluated. • Tracer gas and blower door tests have been performed to update infiltration model. • The rooftop unit performance curve has been developed using field datasets. • The simulation results are well-matched with field data at zonal- and system-level. [ABSTRACT FROM AUTHOR]

Excavation on jobsites is a collaborative effort, with a spotter serving as an extra set of eyes for the operator to ensure safety. However, current training methods using simulators are limited in immersion and primarily designed for individual operators to practice basic skills. This paper presents a multi-user teleoperation system featured with hybrid-immersive interface and between-user communication. The effectiveness of the system is evaluated through human subject experiments. The study's findings indicate that operators experienced greater immersion, a stronger sense of presence, and improved user interaction when using an immersive interface. This paper has important implications for the future of excavation training, with potential benefits including reduced utility strike damage and the opportunity to investigate human-robot collaboration in jobsites with multiple workers performing various roles within a highly immersive operational environment. • A multi-user excavator simulation system composed of robotic control, motion capture, and hybrid-immersive interfaces. • Human subject experiments with 57 subjects to evaluate the proposed system. • The effectiveness of the system is validated by achieving higher performance metrics than the monitor-based system. • Task completion time, accuracy, and safety are significantly improved under collaborative operation with a spotter. • Enhanced human factors study of the multi-user interaction with multi-roles in the human-robot collaboration in jobsites. [ABSTRACT FROM AUTHOR]