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Burden is one of the most important parameter which plays an immense role in rock breakage using explosive energy. It is very difficult to select the optimum burden under different geotechnical and geomining condition. The selection becomes more critical when the excavation method is underground as very few researches or studies have been carried out in such cases. Therefore, in this paper, numerical simulation-based approach has been employed to estimate the optimum burden for ring blasting. The numerical models were created under different scenario including blasthole diameter and strength of the rock. The RHT concrete constitutive model has been used in this paper to study the damage contour under different circumstances. The model output has been used to calculate the volume of rock damage along the free face. This damage volume is further correlated with various parameters. This correlation shows that the damage volume along the free face initially rises with the increase in burden and then starts decreasing after a certain value. The burden value which recorded the maximum volume of rock excavated along the free face has been considered as the optimum burden in this paper. The trial blast has been also carried out at the experimental site for twenty-four rings. The optimum burden achieved from the experimental trial for 102 mm blasthole diameter and rock having uniaxial compressive strength as 92 MPa lies between 2.4 and 2.65 m. However, the optimum burden predicted through developed empirical equation from the numerical model is 2.6 m. The study shows that the simulation-based prediction exhibits a minor deviation within 15% with the experimental result. Hence, to assess the optimum burden under various geotechnical and geomining circumstances, numerical simulation-based approach may be carried out using the proposed methodology. Highlights: Burden for ring blasting is optimised using different numerical simulation models. Volume of rock excavated along free face (EV) has been calculated in each case. The optimum burden from experimental trial and empirical data is 2.4–2.65 m. The optimum burden predicted from developed model is 2.6 m. [ABSTRACT FROM AUTHOR]

With the continuous expansion of computer system simulation applications, the dynamic system modeling problems that people face have become more and more complex. This paper mainly studies dynamic system simulation models and algorithms based on artificial neural networks. This article mainly focuses on some practical problems of dynamic system simulation, and studies the artificial neural network model and corresponding algorithm suitable for dynamic system modeling. First, it summarizes the existing artificial neural network simulation models of dynamic systems: multi-layer feedforward network relationship model without feedback, recursive network relationship model with feedback, and their network topology diagrams are drawn. Secondly, a quantum genetic algorithm is proposed to optimize the parameters of artificial neural networks and feedforward process neural networks. To achieve the preprocessing of the parameters. Next, based on the analysis and research of BP neural network theory, this paper comprehensively compares the neural network models established under various network structures and algorithms, and establishes the simulation model based on the BP neural network monitoring data system, and compares the results with the monitoring data obtained in the field. The hidden layer of neural network with 4 and 6 nodes will increase the convergence step. When the number of nodes is 10 and 12, the convergence rate may reach 46 steps. This shows that if the non-display layer with different number of nodes in the same layer is selected for the same system simulation model based on artificial neural network, the repetition number of convergence steps of the prediction model will be different. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the editor discusses various reports within the issue on topics related to visual computer including sketch-based modeling, character animation, and physics-based simulation.

With the advancement of simulation-based training, intelligent agents that can display human-like behavior have become common. From military combat simulations to nuclear power plant simulation, agents have been widely used to facilitate team training (as team mates, opponents, or both). Credibility of these agents is vital to ensure a sound training process. Credibility of the agents largely depends on the credibility of the underlying human behavior representation (HBR) model. This is why validation of the HBR model is necessary to ensure realistic agent behavior. However, the non-deterministic nature of the HBR and the subjectivity in experts' judgment during the validation process make HBR model validation more challenging compared to physics based models. This paper presents the validation process of an HBR model of general personnel created for use in an offshore emergency training simulator. Three types of agents (naïve, in-between, and ideal) are created in the simulator using the HBR model. The paper discusses the use of empirical evidence as referents, along with subject matter experts. A two-level three factor experiment was conducted using 36 participants. Several performance metrics were collected during the experiment, including route selected for evacuation, time to muster, time spent running, interaction with fire doors and watertight doors, interaction with hazards, and reporting to the muster station. Data collected during the experimental study have been used in this paper to demonstrate how the use of empirical evidence can facilitate HBR validation. High-level tasks performed during HBR validation are discussed in detail. Special emphasis is given on acceptability criteria testing to ensure that the HBR model performs adequately under different operating conditions. Results show that the proposed HBR model meets the acceptability criteria requirement for all types of agents. In general, the ideal agents exhibited safe behavior during offshore emergency egress, whereas the naïve and in-between agents showed erroneous behavior at times. For example, during the simulation runs of a critical emergency scenario where the primary egress route was obstructed by a hazard, the ideal agents either waited and listened to the public address announcement and followed an alternative egress route (60% cases), or they initially chose their preferred route but re-routed immediately after encountering the hazard (40% cases). In all cases, the in-between agents started with their preferred route and re-routed after encountering the hazard, and the naïve agents proceeded with their preferred route even when the route was compromised. [ABSTRACT FROM AUTHOR]

This paper describes the development of a 3D simulator that enables a user to analyze the stability of a finite slope causing plane activity among a range of slopes comprised of a finite slope and infinite slope. Until now, there has been considerable theory and research into slope stability. Nevertheless, few systems can be confirmed directly by simulating the stability analysis of a slope, such as landslides. In other words, virtual experiments, such as the analysis of the slope, cannot be performed due to the absence of a system. For that reason, in this study, a 3D simulator was developed for stability analysis of a finite slope causing plane activity from the landslide phenomena that actually occurred or had very high probability. The Nvidia PhysX, which is utilized to develop computer games and simulators, was used to develop a 3D simulator with physical features. In addition, OpenGL was used to provide a three-dimensional visual effect from the simulator. In this paper, the values of each variable were determined to confirm whether landslides can occur easily when the factor of safety ( F) was within a certain range in the 3D simulator. The 3D simulator developed in this paper was found to be quite useful because it can verify visually whether landslides occur easily in different environments and conditions. [ABSTRACT FROM AUTHOR]

Numerical simulations consist of many components that affect the simulation accuracy and the required computational resources. However, finding an optimal combination of components and their parameters under constraints can be a difficult, time-consuming and often manual process. Classical adaptivity does not fully solve the problem, as it comes with significant implementation cost and is difficult to expand to multi-dimensional parameter spaces. Also, many existing data-based optimization approaches treat the optimization problem as a black-box, thus requiring a large amount of data. We present a constrained, model-based Bayesian optimization approach that avoids black-box models by leveraging existing knowledge about the simulation components and properties of the simulation behavior. The main focus of this paper is on the stochastic modeling ansatz for simulation error and run time as optimization objective and constraint, respectively. To account for data covering multiple orders of magnitude, our approach operates on a logarithmic scale. The models use a priori knowledge of the simulation components such as convergence orders and run time estimates. Together with suitable priors for the model parameters, the model is able to make accurate predictions of the simulation behavior. Reliably modeling the simulation behavior yields a fast optimization procedure because it enables the optimizer to quickly indicate promising parameter values. We test our approach experimentally using the multi-scale muscle simulation framework OpenDiHu and show that we successfully optimize the time step widths in a time splitting approach in terms of minimizing the overall error under run time constraints. [ABSTRACT FROM AUTHOR]

This paper presents the outcomes of a sequence of three-dimensional numerical simulation models conducted in linear cutting mode, employing the LS-DYNA software. The primary objective was to scrutinize the side force values exerted on the gauge cutters. To accomplish this, an assortment of simulation models was meticulously constructed and executed, employing the Lagrange and SPG computational algorithms, along with the JHC and RHT constitutive material models. By comparing the outcomes of these models with the linear cutting experiments documented in the literature, specifically concerning the Colorado red Granite, it was determined that the SPG computational algorithm and the RHT constitutive material model proved to be the most suitable for simulating rock-cutting scenarios. Building upon the chosen computational algorithm and constitutive material model, a series of numerical models was then crafted to simulate the penetration of gauge cutters in both longitudinal and transverse orientations relative to their tips. Subsequently, the applied side forces were extracted, and a statistical model was developed to accurately predict the side forces experienced by the gauge cutters, yielding a coefficient of determination of 93%. [ABSTRACT FROM AUTHOR]

The paper analyses the combined effect of fin number (n) and inclination (β) on the overall performance of the PV module in the finned PV-PCM system by numerical simulation. System geometries with no fin to four fins are considered with inclinations varying from 0° to 45° to obtain different configurations of the PV-PCM system. Performance parameters such as mean temperature, PV efficiency, PV power output, mean velocity, and temperature contours are simulated for all the system configurations. The system is subjected to actual dynamic conditions such as variable solar radiation and ambient temperature. The maximum temperature reduction is obtained for the three-finned system with an inclination of 45°. The inclusion of fins is relatively effective for horizontal systems compared to other inclinations, and the highest relative enhancement in efficiency of 5.56% is obtained for horizontal PV-PCM system with 4 fins. Three-finned PV-PCM system with a 45° inclination angle produces the highest instantaneous PV electrical power output of 165.87 W and the lowest peak PV temperature of 50.23 °C, which is the optimum. The peak average velocity of melted PCM is maximum for unfinned PV-PCM system with β = 45 ∘ , indicating the presence of the highest strength of convection current in melted PCM. [ABSTRACT FROM AUTHOR]

Digital image technology is penetrating into various fields of people's life, and it has been very mature and can effectively store and transmit data. Moreover, there are still various researches on image recognition, the core of this technology. The algorithm is mainly based on computer technology to obtain the target image for different scene categories, thus completely replacing the traditional classification form. Because of the limitations of traditional identification technology, there are some problems in the actual use. It does not depend on the prior knowledge requirements and can carry out complex feature space division. In this paper, an image recognition computer system is established by introducing an improved neural network algorithm. The algorithm is designed and tested, and the results show it has lower image recognition error rate. Subsequently, this research result is applied to the actual scene for testing. The test results show that the improved neural network optimization algorithm can make the extracted features more accurately expressed in the image processing, which is more effective than the traditional algorithm. [ABSTRACT FROM AUTHOR]

This paper is to contribute a new dynamic channel access method for wireless local area networks. It allows a station accessing the 80 or 160 MHz channel to capture every idle non-primary 20 MHz channel along with the primary 20 MHz channel, whereas the number of channel configurations in which the station can transmit according to the 802.11ac standard is strictly limited. Simulation results shown in the paper prove the proposed access method to be superior to the method provided by the 802.11ac standard in terms of average network throughput. What is important for legacy reasons, the proposed method employs the conventional clear channel assessment function to determine which of the 20 MHz channels are idle and which are busy. The paper proposes a new receiver design that is able to reject the adjacent channel interference, arising as a result of the presence of the legacy 802.11a/n station signals inside the 80 or 160 MHz accessed channel. [ABSTRACT FROM AUTHOR]

The droplet impact on solid surfaces is a popular research topic in which many researchers focus on stationary surfaces, only a few researches have been conducted for moving surfaces. In this paper, a high-speed photography-based droplet impact experimental platform and a VOF-based numerical simulation model are built to study the morphology of motion of a droplet after it impacted a horizontal uniformly moving surface. In the present study, the tangential and normal Weber numbers range within 70. This is because at such low Weber numbers the droplets initially spread to their maximum diameter after impacting the moving surfaces and subsequently start to rebound. The studies have confirmed that the maximum spreading factor of the droplet increases linearly with the tangential Weber number, and the spreading time increases as well. The maximum spreading factor of the droplet increases nonlinearly as a function of the normal Weber number and corresponding time initially increases and then decreases. Finally, the expression for the maximum spreading factor is fitted according to its correlation with the We number. [ABSTRACT FROM AUTHOR]

This paper is a study on energy efficiency prediction model of heavy-duty electric vehicles using numerical simulation. Because the current energy consumption efficiency evaluation method for electric vehicles has limitations in terms of manpower, resources, and time required, therefore a simulation model development to predict electric vehicle energy consumption efficiency is needed. Furthermore, research on heavy-duty electric vehicles is relatively insufficient compared to light-duty electric vehicles, and the need of research on heavy-duty electric vehicles is increasing. Therefore, this study develops an energy efficiency prediction model for heavy-duty electric vehicles and verifies it with the experimental results. Based on this, the applicability of the simulation method using the developed prediction model to the current energy efficiency evaluation management system for heavy-duty electric vehicles was reviewed. To verify the accuracy of the simulation model, the dynamometer test results were compared to simulation results, and the UDS protocol was used to acquire internal data for heavy-duty electric vehicles. Reliability of simulation model was secured by comparing data such as motor speed, battery voltage/current, state of charge and total driving distance of the test vehicles with data from the dynamometer experiment and the simulation model. [ABSTRACT FROM AUTHOR]

This paper studies a class of fractional-order systems (FOSs) and proposes control laws based on physical significance variables. Lyapunov techniques and the methods that derive from Yakubovici–Kalman–Popov Lemma are used, and the frequency criterions that ensure asymptotic stability of the physical significance variable closed-loop system are inferred. The asymptotic stability of the observer system is studied for a sector control law where the output is defined by the physical significance variables. Frequency criterions and conditions for asymptotic stability are determined. The control techniques are extended to a class of linear delay fractional-order systems and nonlinear FOS. Numerical simulations of a class of systems described by fractional-order models show the method efficiency. [ABSTRACT FROM AUTHOR]

This paper describes a method for determining the strain state of a thin anisotropic plate with elastic arbitrarily arranged elliptical inclusions. Complex potentials are used to reduce the problem to determining functions of generalized complex variables, which, in turn, comes down to an overdetermined system of linear algebraic equations, solved by singular expansions. This paper presents the results of numerical calculations that helped establish the influence of rigidity of elastic inclusions, distances between inclusions, and their geometric characteristics on the bending moments occurring in the plate. It is found that the specific properties of distribution of moments near the apexes of linear elastic inclusions, characterized by moment intensity coefficients, occur only in the case of sufficiently rigid and elastic inclusions. [ABSTRACT FROM AUTHOR]

This paper deals with the implementation of real-time image processing of rendered virtual scenes, where lighting calculations are produced in a high dynamic range. In this paper we propose a new method for realization of images' tone compression and modeling of 'bloom' effect over bright areas using parallel computing on the GPU in real-time. The method is based on a modified version of the Reinhard's global tone operator with the original algorithm of calculating global luminances of the frame and provides a simulation of the effect of blooming bright areas of the image. The proposed solution can be used in visualization for simulators and virtual environment systems. [ABSTRACT FROM AUTHOR]

It is of crucial importance whether or not evacuees follow the evacuation signs during building evacuation. It is necessary for effective evacuation signs to be designed in a way that helps the occupants follow building safety guidelines. In this paper, 658 evacuation experiments with wearable eye tracking devices were carried out to test the effectiveness of both the setting positions and design of evacuation signs in buildings. There are four factors considered in this paper: (1) position, (2) colour, (3) graphics, and (4) (or flashing). The results show that the effect of the green "arrow" evacuation sign is the best. The effect of low (corridor) signs works better than those of high (room) signs, but the signs of low (corridor) could be blocked by the front evacuees. Obtaining the ratio of people obeying the evacuation signs under different conditions provides an effective basis for the improvement in design for building safety, and provides data support for computer simulation modelling of crowd evacuation. [ABSTRACT FROM AUTHOR]

In previous studies, the numerical modeling and analyzing methods onto industrial or vehicle airbags dynamics were revealed to have high accuracy regarding their actual dynamic properties, but there are scarcely airbag stiffness modeling and comfortableness investigations of nursing cushion or mattress airbags. This study constructs a numerical model illustrating the association between the stiffness property and the internal gas mass of the wedge-shaped airbag of nursing appliance, and then the airbag stiffness variation discipline is described based on various inflation volumes. To start with, based on an averaged pressure prerequisite, a dynamic simulation model of the wedge-shaped airbag is established by the fluid cavity approach. For this modeling, the elastic mechanical behaviors of airbag material are determined according to a material constitutive model built by the quasi-static uniaxial tensile test. Besides, verification experiments clarify that the presented modeling method is accurate for airbag stiffness behavior prediction, and then can be effectively applied into design and optimization phases of wedge-shaped airbags. Ultimately, based on the simulation and experimental results, it is found that the wedge-shaped airbag stiffness exhibits a three stages characteristic evolution with the gas mass increase. Then the mathematical relationship between the airbag stiffness and gas mass is obtained by numerical fitting, which provides a vital basis for structural optimization and differentiated control of nursing equipment airbags. [ABSTRACT FROM AUTHOR]

The mechanism of rock fracture evolution under loading has always been the focus of rock mechanics community. In this paper, to realize the development of rock crack propagation simulation system based on ABAQUS platform, the failure criterions which involve maximum tensile stress criterion, the maximum compressive stress criterion and the Mohr–Coulomb failure criterion (M–C) are programmed into the VUMAT subroutine, and the failure element deletion algorithm is introduced to investigate the deformation and failure process of rock blocks under load. Then, the proposed system is used to analyze the progressive failure process of rock samples under loading. By comparing with the test results, the causes and characteristics of crack expansion are studied, meanwhile the different forms of the rock failure process are explored. [ABSTRACT FROM AUTHOR]

The aim of the paper is to present a case study and to point out the possibilities of using computer simulation for the purpose of increasing the efficiency and efficiency of custom production of a company. The use of simulation modeling as a scientific method in research and in practice brings benefits such as financial, time, material and energy savings, as well as streamlining activities in real practice. The development of advanced simulation systems has opened up new possibilities and significantly supported the trend of streamlining production activities, thus reducing costs and improving business performance. Simulation, however, is not a tool for obtaining an optimal solution, but rather a tool that allows you to test different decision outputs on a simulation model. Such a simulation model makes it possible to carry out various experiments to evaluate, analyse and determine solution parameters that can then be used in a real system. Risk factors can be investigated and determined beforehand by 'replacing' the running simulation model while monitoring system performance and behaviour, then, after applying the required changes, the future behaviour of the system is examined for any potential problems and obstacles. Can be removed in advance. The goal is to analyse the material flow in the production process and then create a simulation to determine the length of production and identify bottlenecks in the production process. In order to get a better idea of the production process, a simulation model was developed in the selected software tool as a custom production project under the conditions of a particular company. The incentive to start production is given to the customer, where every order placed is immediately sent to the customer. The highest frequency order in the enterprise's production program is used to create the material flow. [ABSTRACT FROM AUTHOR]

This paper presents a human-centered modeling framework of urban systems to capture various types of interdependency underlying urban sociotechnical and socioeconomic systems. The proposed framework consists of three major subsystems: civil life, manufacturing/service industry, and lifeline infrastructure. This framework classifies nine different types of interdependencies existing within and between these three subsystems. This paper also presents a computer simulation of the post-disaster recovery process of urban systems considering various interdependencies captured by the modeling framework. We adopt an agent-based model incorporating a network model for implementing the three subsystems as well as the various types of interdependencies. A sensitivity analysis was conducted based on the R4 framework of disaster resilience to verify and validate the simulation model. The simulation results were generally consistent with the predictions made by the R4 framework, suggesting that the model was implemented properly and can capture the multiple interdependencies behind the urban systems. [ABSTRACT FROM AUTHOR]

Wildfire evacuation triggers refer to prominent geographic features used in wildfire evacuation practices, and when a fire crosses a feature, an evacuation warning is issued to the communities or firefighters in the path of the fire. The existing wildfire trigger modeling methods consider evacuation time as an input from a decision maker and employ fire spread modeling and GIS to create a trigger buffer around a threatened asset. This paper substantially improves on previous methods by coupling fire and traffic simulation models to set triggers, which allows us to estimate evacuation time using a traffic simulation model rather than relying on expert judgment. Specifically, we propose a three-step method within a spatiotemporal GIS framework to couple these models and to evaluate the value of the generated trigger buffers. The first step uses traffic simulation to estimate the total evacuation time for a threatened community. The second step derives the cumulative probabilities for distinct evacuation times from multiple simulations and generates corresponding probability-based trigger buffers. In the last step, we evaluate the value of the generated buffers by coupling fire and traffic simulation models to examine the spatial configurations of fire perimeters and evacuation traffic. A case study of Julian, California is used to test the proposed method. The results from two evacuation scenarios with different travel demand indicate that a larger trigger buffer (more lead time) will be needed for higher levels of evacuation travel demand. For example, the time required to guarantee that 95% of the evacuating residents arrive at the safe area as a fire approaches a community is estimated at 160 min for one scenario but 292 min if the travel demand is doubled. The resulting framework advances the dynamic representation of evacuation traffic in wildfires and improves our understanding of wildfire evacuation timing and decision making. The paper concludes with a discussion of the strengths and limitations of the proposed method, as well as future research directions. [ABSTRACT FROM AUTHOR]

In this paper, a class of three-neuron network with discrete and distributed delays is introduced. We first give a detailed Hopf bifurcation analysis for the proposed network. Choosing the discrete time delay as a bifurcation parameter, the existence of Hopf bifurcation is studied. Moreover, by using the normal form theory and center manifold theorem, the formulae determining the direction of the bifurcations and the stability of the bifurcating periodic solutions are derived. Finally, numerical simulations are presented to demonstrate the effectiveness of our theoretical results. [ABSTRACT FROM AUTHOR]

This paper presents a novel hybrid observer structure to estimate the lateral tire forces and road grip potential without using any tire-road friction model. The observer consists of an Extended Kalman Filter structure, which incorporates the available prior knowledge about the vehicle dynamics, a feedforward Neural Network structure, which is used to estimate the highly nonlinear tire behavior, and a Recursive Least Squares block, which predicts the road grip potential. The proposed observer was evaluated under a wide range of aggressive maneuvers and different road grip conditions using a validated vehicle model, validated tire model, and sensor models in the simulation environment IPG CarMaker®. The results confirm its good and robust performance. [ABSTRACT FROM AUTHOR]

Designing Unmanned Aircraft Systems (UASs) for optimal autonomy while meeting user requirements is quite challenging. Researchers have focused on improving autonomy algorithms and verification methods to ensure safe and reliable autonomous behavior in UASs, but little research has been conducted on requirements engineering for UASs to answer design questions and explore the trade space for using autonomy to satisfy user requirements. This paper introduces a method to determine an optimal set of autonomous capabilities that satisfies UAS user requirements in the early stages of conceptual design. The method uses a modified Autonomy Requirements Engineering (ARE) process that applies quantitative measures and statistical analysis to Goal-Oriented Requirements Engineering (GORE). We demonstrate this method in a case study of a “disaster robot,” i.e., a hazard response UAS for which the autonomy requirements were optimized using a goal model developed in the Goal-oriented Requirement Language (GRL), as implemented in the modeling tool jUCMNav. The high-level goals of the hazard response UAS—system performance, cost, and safety—were evaluated using the formula-based GRL strategy evaluation algorithm resident in jUCMNav version 6.0. An autonomy trade space study was conducted through a Design and Analysis of Simulation Experiments (DASE). Our designed simulation experiment inserted the number of trials (evaluation strategies) and inputs into the goal model, and evaluation data were analyzed to optimize design factors based on user weightings of the response variables. This paper presents a structured method of ARE for UASs, which could be adopted more broadly across other domains, demonstrating how to optimize autonomous capabilities for different design conditions. [ABSTRACT FROM AUTHOR]

Abstract  We present a novel unified framework for simulating burning phenomena of thin-shell objects such as paper, cloth, etc. A gradient-based spreading model is proposed to simulate the movement of fire on thin-shell objects. To simulate the crumpling and deformation of thin-shell objects when burning, we present an FFD-based deformation model which takes the physical theory of burning phenomena into account. The fire is rendered by the method of particle systems. By inputting different parameters and initial conditions, our framework can simulate various burning phenomena of different thin-shell objects. Experiments validate that it is efficient and easy to implement. [ABSTRACT FROM AUTHOR]

Teaching the use of models in scientific research requires a description, in general terms, of how scientists actually use models in their research activities. This paper aims to arrive at defining common characteristics of models that are used in present-day scientific research. Initially, a list of common features of models and modelling, based on the literature was compiled. Next, a questionnaire was developed, which consisted of 10 statements with which the common features of models were probed. A sample of 77 research papers from ‘hard science’ journals was drawn. The questionnaire was sent to the first author of the selected articles. The useful response was 24 (31%). From an analysis of the results, it was concluded that the consulted scientists more or less agreed with the initial list of common features of models and modelling. However, some characteristics were perceived differently by the respondents, or formulated in different terms. This has led us to revise some of the features in our list. It is recommended that in science curricula and science text books, more attention should be paid to modern uses of models (e.g., in the context of computer simulation and technological design), and that aspects of the nature of models (e.g., the relation between model and target, and possible limitations of a model), which are underexposed in education, are addressed more explicitly. [ABSTRACT FROM AUTHOR]

Twin-field quantum key distribution (TF-QKD) is a new extraordinary QKD protocol, which can overcome the fundamental rate-distance limit without quantum repeaters. Moreover, its variant, the sending-or-not-sending twin-field quantum key distribution (SNS-QKD) protocol, can both tolerate large misalignment error and have a higher key rate; however, the light source is assumed to be the trusted one in the original SNS protocol. In this paper, we propose a more practical SNS-QKD protocol with plug-and-play architecture, named P & P SNS-QKD protocol. We present the framework of P & P SNS-QKD protocol and analyze the tight bound of its key rate with the four-intensity decoy-state method. The proposed protocol can avoid the careful adjustments, and the control of the system and the numerical simulations results show that the proposed protocol has a close key generation rate to that of the original SNS-QKD. Besides, the proposed protocol still maintains a high tolerance for misalignment errors even if the source is unknown and untrusted. [ABSTRACT FROM AUTHOR]

Cooperative adaptative cruise controls and variable speed limit are gaining notoriety in recent years to fulfill the aim of reducing traffic congestions. Improvements in the management of hazardous materials, combined with these technologies, can reduce damages caused by congestions, mitigate risks to human health, and avoid environmental leakage. Drivers' behaviors are directly influenced by human beings' different reactions. Therefore, the variance in traffic produces shockwaves, rippling traffic waves, and a reduction of the traffic flow capacity. This paper aims to present adaptative optimal control of nonlinear systems simulation as a tool to prove the effects of the predictions according to drivers' behavior. Furthermore, it supports the decision making of hazardous material traffic management. Traffic engineering and queuing theory are also addressed. [ABSTRACT FROM AUTHOR]

In this paper, a hybrid optimization technique based on particle swarm optimization (PSO) and artificial bee colony (ABC) algorithm is presented for the optimal design of infinite impulse response (IIR) filter with low quantization effect. In this method, different variants of PSO have been exhaustively tested, and the time varying coefficients-PSO (TVC-PSO) is used to formulate a new hybrid technique for better exploitation and exploration, which is further modified by sorting and replacement mechanism of Scout Bee from ABC algorithm. For designing IIR filter, an objective function is constructed that satisfies the absolute error including peak ripples in passband and stopband regions in frequency domain, while stability of designed filter is confirmed by exploiting the lattice form structure during iterative computation that also reduces computation complexity. Several attributes such as passband error (ep), stopband error (es), and stopband attenuation (As) are used to measure the performance of proposed algorithm. The simulation results presented in this paper evidence that this technique can be effectively used for designing digital IIR filter with higher filter taps, and low quantization effect for fixed number of bits. [ABSTRACT FROM AUTHOR]

A spatial odor distribution in an environment can be used for navigation, goal search, localization and mapping, like by video, ultrasonic, temperature and other sensors. Modern e-noses can perform the selective detection of different gases with an extremely low concentration but the source localization algorithms of a selected gas against the background of other odors are still underinvestigated. This paper studies an odor field representation in terms of an e-nose based on an array of low-selective sensors. Using a simulation model, we show how the vector measurements of a field of several odor sources can be processed to navigate for reaching a selected odor source. In addition, we demonstrate that the source having a high level of odor intensity can interfere with the search of another odor source of a low intensity. The well-known class of matching receivers does not solve this problem. However, a solution can be obtained by distributed measurements. As shown below, the spatial structure of an odor field allows to implement vector selection. Using deep learning machines, we may reach a high resolution of odor sources in the space. Our future research will be focused on augmented odor reality and autonomous mobile e-nose (e-dog) design. [ABSTRACT FROM AUTHOR]

The predator-prey model is powerful mathematical tool to describe the dynamics of biological systems and promote research on biological populations. In this paper, we present a lumped mass finite element method for solving the predator-prey models on surfaces. The main purpose of the proposed method is to overcome the difficulty of the positivity preservation of the solutions. Based on positivity preservation results, we investigate the stabilities of semi-discrete and fully discrete approximations. Besides, numerical simulations are considered to illustrate the feasibility of the numerical method by convergence tests. Two classical phenomena of the predator-prey model are simulated on three different implicit surfaces. [ABSTRACT FROM AUTHOR]

In this paper, our aim is mathematical analysis and numerical simulation of a prey-predator model to describe the effect of predation between prey and predator with nonlinear functional response. First, we develop results concerning the boundedness, the existence and uniqueness of the solution. Furthermore, the Lyapunov principle and the Routh–Hurwitz criterion are applied to study respectively the local and global stability results. We also establish the Hopf-bifurcation to show the existence of a branch of nontrivial periodic solutions. Finally, numerical simulations have been accomplished to validate our analytical findings. [ABSTRACT FROM AUTHOR]

This paper presents an optimal design of low noise amplifier (LNA) using an efficient swarm-based optimizer called firefly algorithm (FA). Many researchers have used firefly algorithm to solve various nonlinear engineering problems and reported outstanding results. In view of this, FA is implemented for the first time in this paper to optimize the parameters of LNA like gain and noise figure (NF). Two case studies have been performed which includes the minimization of NF and maximization of gain. Optimization of these two parameters has been carried out by considering each parameter as a single objective function. Penalty factor method is considered for handling the constraints. Other parameters of LNA like power consumption, linearity, and stability are also discussed for both the cases. The designed LNA has a cascode structure with inductive source degeneration topology and is implemented in UMC 0.18-μm CMOS technology using CADENCE software. LNA is designed for 5.5-GHz frequency. The performance of FA in optimizing the parameters of LNA is also compared with the performance of other similar contemporary algorithms like particle swarm optimization (PSO), human behavior PSO (HB-PSO), backtracking search algorithm, and cuckoo search algorithm (CSA). The optimized value of LNA parameter using FA and other algorithms when simulated in MATLAB environment is compared with the simulated result of CADENCE. Statistical analysis is also performed for each case study, and the results are compared with the above-mentioned optimization algorithms. Simulation results, comparative study, and statistical analysis confirm the superiority of FA over other methods in terms of its computational efficiency, consistency, and robustness. [ABSTRACT FROM AUTHOR]

Double-layered shaped charge (DLSC) is a special type of shaped charge which has been recently attracted to enhance the penetration performance. The DLSC consists of a co-axial double-layered charge composed of outer high-velocity explosive and inner low-velocity explosive. In this paper, numerical simulations and experiments are carried out to investigate the usefulness of the DLSC compare to an ordinary shaped charge (OSC) at different stand-off distances. Jet properties of shaped charges are measured by simulation models and compared with the experimental penetration depths. It was found that the penetration performance strongly depends on the existence of jet breakup and the DLSCs performed better than the OSC only when no jet breakup occurs before reaching the target. The comparison study between the simulations and experiments also revealed that the jet properties such as kinetic energy, cumulative jet mass, and the initial jet breakup distance are highly related to the penetration performance. [ABSTRACT FROM AUTHOR]

As microscale cooling structures are integral parts of modern chip level cooling concepts, the understanding the behaviour of different assemblies is desirable. This way novel co-design concepts can be created where the conventional IC design steps are extended with thermal design capabilities resulting in a SiP/SoP design flow. The first step in this process is to create a general formula which describes the heat transfer mechanism and can be implemented in IC CAD environments as a compact model. This paper presents an analytical study of an integrated microscale channel based cooling structure with the above motivation in mind. A closed analytical formula is given to calculate the partial thermal resistance corresponding to the heat transfer represented by the coolant which can be used in electro-thermal co-simulation. The analyses based on numerical CFD simulations and thermal transient characterizations of a realized structure are also discussed and the results are compared against the analytical ones. [ABSTRACT FROM AUTHOR]

Background: Numerous studies examine simulation modelling in healthcare. These studies present a bewildering array of simulation techniques and applications, making it challenging to characterise the literature.Objective: The aim of this paper is to provide an overview of the level of activity of simulation modelling in healthcare and the key themes.Methods: We performed an umbrella review of systematic literature reviews of simulation modelling in healthcare. Searches were conducted of academic databases (JSTOR, Scopus, PubMed, IEEE, SAGE, ACM, Wiley Online Library, ScienceDirect) and grey literature sources, enhanced by citation searches. The articles were included if they performed a systematic review of simulation modelling techniques in healthcare. After quality assessment of all included articles, data were extracted on numbers of studies included in each review, types of applications, techniques used for simulation modelling, data sources and simulation software.Results: The search strategy yielded a total of 117 potential articles. Following sifting, 37 heterogeneous reviews were included. Most reviews achieved moderate quality rating on a modified AMSTAR (A Measurement Tool used to Assess systematic Reviews) checklist. All the review articles described the types of applications used for simulation modelling; 15 reviews described techniques used for simulation modelling; three reviews described data sources used for simulation modelling; and six reviews described software used for simulation modelling. The remaining reviews either did not report or did not provide enough detail for the data to be extracted.Conclusion: Simulation modelling techniques have been used for a wide range of applications in healthcare, with a variety of software tools and data sources. The number of reviews published in recent years suggest an increased interest in simulation modelling in healthcare. [ABSTRACT FROM AUTHOR]

This paper deals with blind residual carrier frequency offset (CFO) and timing offset (TO) estimation based on minimum output variance (MOV) criterion without devoting training sequence and pilot symbol for uplink multicarrier-code division multiple access (MC-CDMA) systems. It has been shown that the performance of MOV estimator is degraded because the effect of noise and wideband spread-spectrum signals. In conjunction with spreading code-aided and subspace projection techniques, we present an improved code-aided MOV (ICMOV) estimator to achieve the high accuracy estimate for the noisy case. Due to more accuracy residual CFO estimate can provide more accuracy residual TO estimate, this paper also present a decision-directed ICMOV (DD-ICMOV) approach to improve the estimation performance of ICMOV estimator. Computer simulations are provided for illustrating the effectiveness of the proposed approaches. [ABSTRACT FROM AUTHOR]

Synchrotron x-ray topography with a high-resolution setup using 11-28 reflection was carried out on 4H-SiC epilayers. Four different shapes of threading-edge dislocation according to Burgers vector direction were observed. The four types of threading-edge dislocation images were calculated by computer simulation, and the experimental results correlated well with the simulation results. The detailed topographic features generated by plural screw dislocations and basal plane dislocations were also investigated. [ABSTRACT FROM AUTHOR]

This paper describes the working principles of an algorithm for boundedness analysis of open Chemical Reaction Networks endowed with mass-action kinetics. Such models can be thought of both as a special class of compartmental systems or a particular type of continuous Petri Nets, in which the firing rates of transitions are not constant or preassigned, but expressed as a function of the continuous marking of the network (function which in chemistry is referred to as the 'kinetics'). The algorithm can be applied to a broad class of such open networks, and returns, as an outcome, a classification of the possible dynamical behaviors that are compatible with the network structure, by classifying each variable either as bounded, converging to 0 or diverging to ∞. This can be viewed as a qualitative study of Input-Output Stability for chemical networks, or more precisely, as a classification of its possible I-O instability patterns. Our goal is to analyze the system irrespectively of values of kinetic parameters. More precisely, we attempt to analyze it simultaneously for all possible values. Remarkably, tests on non-trivial examples (one of which is discussed in this paper) showed that, as the kinetic constants of the network are varied, all the compatible behaviors could be observed in simulations. Finally, we discuss and illustrate how the results relate to previous works on the qualitative dynamics of closed reaction networks. [ABSTRACT FROM AUTHOR]

This paper describes an investigation of a high-strength concrete frame reinforced with high-strength rebars that was tested in the structure engineering laboratory at Shenyang Jianzhu University. The frame specimen was pseudodynamically loaded to indicate three earthquake ground motions of different hazard levels, after which the test specimen was subjected to a pseudo-static loading. This paper focuses on the design, construction and experiment of the test frame and validation of the simulation models. Research shows that a high-strength concrete frame reinforced with high-strength rebars is more efficient and economical than a traditional reinforced concrete frame structure. In addition to the economies achieved by effective use of materials, research shows that the frame can provide enough strength to exceed conventional reinforced concrete frames and provide acceptable ductility. The test study provides evidence to validate the performance of a high-strength concrete frame designed according to current seismic code provisions. Based on previous test research, a nonlinear FEM analysis is completed by using OpenSees software. The dynamic responses of the frame structure are numerically analyzed. The results of the numerical simulation show that the model can calculate the seismic responses of the frame by OpenSees. At the same time, the test provides additional opportunities to validate the performance of the simulation models. [ABSTRACT FROM AUTHOR]

Physics-based simulation is increasingly important in virtual manufacturing for product assembly and disassembly operations. This work explores potential benefits of physics-based modeling for automatic learning of assembly tasks and for intelligent disassembly planning in desktop virtual reality. The paper shows how realistic physical animation of manipulation tasks can be exploited for learning sequential constraints from user demonstrations. In particular, a method is proposed where information about physical interaction is used to discover task precedences and to reason about task similarities. A second contribution of the paper is the application of physics-based modeling to the problem of disassembly sequence planning. A novel approach is described to find all physically admissible subassemblies in which a set of rigid objects can be disassembled. Moreover, efficient strategies are presented aimed at reducing the computational time required for automatic disassembly planning. The proposed strategies take into account precedence relations arising from user assembly demonstrations as well as geometrical clustering. A motion planning technique has also been developed to generate non-destructive disassembly paths in a query-based approach. Experiments have been performed in an interactive virtual environment including a dataglove and motion tracker that allows realistic object manipulation and grasping. [ABSTRACT FROM AUTHOR]

Automatic classification of communication signals plays an important role in various applications. This paper presents an efficient method that classifies a variety of communication signals. In this method, a classifier based on a support vector machine is proposed as the multiclass classifier. A combination set of the higher order statistics are proposed as the effective features for representation of the different kinds of communication signals. An optimization algorithm is used for selecting the parameters of the classifier. Simulation results show that the proposed recognizer has high performance even at very low SNRs. [ABSTRACT FROM AUTHOR]

The paper considers the differences between hypothetico-deductive and inductive modeling: between modelers who put their primary trust in their scientific intuition about the nature of an environmental model and tend to produce quite complex computer simulation models; and those who prefer to rely on the analysis of observational data to identify the simplest form of model that can represent these data. The tension that sometimes arises because of the different philosophical outlooks of these two modeling groups can be harmful because it tends to fractionate the effort that goes into the investigation of important environmental problems, such as global warming. In an attempt to improve this situation, the paper will outline a new Data-Based Mechanistic (DBM) approach to modeling that tries to meld together the best aspects of these two modeling philosophies in order to develop a unified approach that combines the hypothetico-deductive virtues of good scientific intuition and simulation modeling with the pragmatism of inductive data-based modeling, where more objective inference from data is the primary driving force. In particular, it demonstrates the feasibility of a new method for complex simulation model emulation, in which the methodological tools of DBM modeling are used to develop a reduced dynamic order model that represents the ‘dominant modes’ of the complex simulation model. In this form, the ‘dynamic emulation’ model can be compared with the DBM model obtained directly from the analysis of real data and any tensions between the two modeling approaches may be relaxed to produce models that suit multiple modeling objectives. [ABSTRACT FROM AUTHOR]

Top-k query processing is a fundamental building block for efficient ranking in a large number of applications. Efficiency is a central issue, especially for distributed settings, when the data is spread across different nodes in a network. This paper introduces novel optimization methods for top-k aggregation queries in such distributed environments. The optimizations can be applied to all algorithms that fall into the frameworks of the prior TPUT and KLEE methods. The optimizations address three degrees of freedom: 1) hierarchically grouping input lists into top-k operator trees and optimizing the tree structure, 2) computing data-adaptive scan depths for different input sources, and 3) data-adaptive sampling of a small subset of input sources in scenarios with hundreds or thousands of query-relevant network nodes. All optimizations are based on a statistical cost model that utilizes local synopses, e.g., in the form of histograms, efficiently computed convolutions, and estimators based on order statistics. The paper presents comprehensive experiments, with three different real-life datasets and using the ns-2 network simulator for a packet-level simulation of a large Internet-style network. [ABSTRACT FROM AUTHOR]

This paper investigates the use of Monte Carlo sampling methods for phase noise estimation on additive white Gaussian noise (AWGN) channels. The main contributions of the paper are (i) the development of a Monte Carlo framework for phase noise estimation, with special attention to sequential importance sampling and Rao-Blackwellization, (ii) the interpretation of existing Monte Carlo solutions within this generic framework, and (iii) the derivation of a novel phase noise estimator. Contrary to the ad hoc phase noise estimators that have been proposed in the past, the estimators considered in this paper are derived from solid probabilistic and performance-determining arguments. Computer simulations demonstrate that, on one hand, the Monte Carlo phase noise estimators outperform the existing estimators and, on the other hand, our newly proposed solution exhibits a lower complexity than the existing Monte Carlo solutions. [ABSTRACT FROM AUTHOR]

In this paper, five novel and minimum number count floating inductor simulators (FIs) are proposed. Three of the presented FIs depending on the passive component choice can provide parallel R–L, (–R)–(–L) and series R–L, (–R)–(–L) from the same configuration while other two provide one of parallel R–L or series R–L. Some of the introduced positive lossy inductor simulators employ a grounded capacitor; accordingly, they are convenient for integrated circuit (IC) implementation. So as to exhibit the performance of the proposed structures, computer simulations based on SPICE program are given. [ABSTRACT FROM AUTHOR]

In this paper, the influence of vibration parameters on twin-roll strip vibration cast-rolling is studied. Through a comparison of vibration and nonvibration cast-rolling experiments with a 7075 aluminum alloy, it is found that the mechanical vibration introduced during the cast-rolling process can refine the grains and inhibit segregation. A thermal-flow-coupled numerical simulation model of the actual twin-roll strip vibration cast-rolling process is constructed to study the time-domain characteristics and frequency-domain characteristics of the flow field and temperature field in the molten pool, and the model is verified by experiments. The simulation results show that the disturbing effect of vibrations on the flow field in the molten pool can increase the nucleation rate by promoting dendrite fusing and inhibit the segregation of alloying elements. The vibration also affects the temperature field. During vibration cast-rolling, the height of the kiss point changes sinusoidally with time. Based on an analysis of the influence of the amplitude and vibration frequency on the temperature field and flow field, the optimal vibration parameters of the vibration cast-rolling process are determined and provide a foundation for the promotion and application of the new technology of vibration cast-rolling. [ABSTRACT FROM AUTHOR]

This paper takes the risk management and countering strategies of a project as the basis of theoretical knowledge, IT modeling and simulation technology. By combining this approach with the processes of large international construction projects, we specifically research the political risk, natural risk, economic risk, design risk and risk of construction preparation in the project approval and early preparation stages. We also emphasize the risk identification, risk estimation, risk evaluation, risk response, risk monitoring and risk management decisions for the importance of the practice of large international projects and subsequently indicate the primary issues and countering strategies in international project risk management that should receive attention during a construction project. [ABSTRACT FROM AUTHOR]

The system dynamic model (SD model) can simulate the dynamic change of the system from the overall perspective and carry out dynamic analysis of the structure, behavior and causality of the system by computer simulation under different assumptions. Therefore, to solve the problem of tripartite game between the government, private sector and owners which caused by the application of PPP model in the old community renovation, this paper establishes a three-party game model based on the evolutionary game theory and simulates the evolvement path of each participant by establishing SD Model with relevant computer Software. The research finds that: (1) the government, the community owners and the private sectors will eventually reach a stable and balanced state (supervision, participation, effort); (2) the government is dominant in the renovation, and the strategic choice of the private sectors and the community owners depends on the government's strategy, the variables determined by the government and the relationship between these exogenous variables; (3) although a single variable could influence the strategic choice of each party, the formation of the final stable state depends on the interaction of multiple variables, and the government should handle the relationship between each stakeholders. [ABSTRACT FROM AUTHOR]

Tunnel excavation in squeezing ground exhibits large time-dependent and often anisotropic deformation. Within the context of the Fréjus road tunnel and its safety gallery excavated under the Alps between France and Italy, an interesting configuration of two parallel tunnels under squeezing ground conditions is observed. The special feature of this case study lies in the fact that both tunnels have been excavated in similar geotechnical conditions but with different excavation techniques. The road tunnel was excavated with conventional drill and blast methods in the 70s, whereas the safety gallery was excavated between 2009 and 2016 with a single-shield tunnel boring machine (TBM). This paper presents monitoring data processing and numerical simulations of both tunnels with the aim of studying the influence of the excavation method on the time-dependent tunnel response. A calibration of a visco-elasto-plastic anisotropic constitutive model based on the back-analysis of convergence measurements retrieved during the excavation of the Fréjus road tunnel is carried out. The identified ground behavior can be extrapolated to the parallel zones of the safety gallery. In particular, we are interested in the prediction of the stress state in the segmental lining of the gallery during its excavation and the comparison with in situ measurements. It is shown that the time-dependent behavior of the ground is affected by the excavation technique. Finally, an attempt to predict the long-term response of both tunnels is proposed. [ABSTRACT FROM AUTHOR]