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Reforms to deploy civilian responders to non-criminal emergency calls may reduce demands on police departments and reduce negative interactions between police and civilians, but there is presently little empirical evidence on the feasibility of these proposals. We develop a model to evaluate which calls could be transitioned to civilian responders based on their crime risk. We use a rich dataset of community-initiated emergency calls to Baltimore Police Department to evaluate the effect of re-tasking based on three call diversion design scenarios. We find that 22 to 57% of 911 calls could be assigned to civilians. We then apply Monte Carlo methods to estimate the financial and time use implications of transferring low risk calls to civilians. Under the most conservative scenario, re-tasking frees police officer time equivalent to 59 additional full-time officers (95% CI: 43 – 75 officers), about nine percent of the Department's current patrol personnel. [ABSTRACT FROM AUTHOR]

One promising paradigm for content-centric communication is Named Data Networking (NDN), which revolutionizes data delivery and retrieval. A crucial component of NDN, producer mobility, presents new difficulties and opportunities for network optimization. This article reviews simulation strategies designed to improve NDN producer mobility. Producer mobility strategies have developed due to NDN data access needs, and these methods optimize data retrieval in dynamic networks. However, assessing their performance in different situations is difficult. Moreover, simulation approaches offer a cost-effective and controlled setting for experimentation, making them useful for testing these technologies. This review analyzes cutting-edge simulation methodologies for NDN producer mobility evaluation. These methodologies fall into three categories: simulation frameworks, mobility models, and performance metrics. Popular simulation platforms, including ns-3, OMNeT++, and ndnSIM, and mobility models that simulate producer movement are discussed. We also examine producer mobility performance indicators, such as handover data latency, signaling cost, and total packet loss. In conclusion, this comprehensive evaluation will help researchers, network engineers, and practitioners understand NDN producer mobility modeling approaches. By knowing these methodologies' strengths and weaknesses, network stakeholders may make informed NDN solution development and deployment decisions, improving content-centric communication in dynamic network environments. [ABSTRACT FROM AUTHOR]

The paper examines the specificity of artificial intelligence-based automatic train operation systems. Justifying the functional safety (FS) of such systems is quite difficult. The paper proposes a process for proving the functional safety of intelligent systems. A hybrid control system for a shunting locomotive was developed and analysed. It combines machine vision (MV), train protection devices and manual control by a driver. A model is presented that allows examining the functional safety of a locomotive control system layer by layer, i.e., evaluating the time to safety degradation depending on the component failure and subsequent requirement of bringing the locomotive to a complete stop. This allows to improve the FS of the shunting locomotive control system with machine vision from SIL 2 to SIL 3 and maintaining it during sufficiently long periods of time (over a quarter of the mean time to system failure). The mean time of faultless operation of a locomotive control system until it has to be brought to a complete stop for safety reasons can be increased three times. A general approach is proposed to design the functional safety of automatic train operation systems. It is based on the division of the information processing process into two subprocesses, i.e., internal intelligent information processing onboard the locomotive for the purpose of decision-making regarding track vacancy and communication of initial visual information to the operating driver for decision-making. The division of this process must be combined with redundant machine vision facilities, regular comparison of the outputs of the onboard and fixed machine vision facilities, redundant comparison outputs, smoothing of the outputs in the process of locomotive movement. [ABSTRACT FROM AUTHOR]

The paper presents analysis of influence of change of physical parameters such as: temperature, friction coefficient and load, during the process of die forging. Optimization of the process effects in achieving high quality products, decreasing shaping resistance, and what follows - lower energy consumption. Temperature is the basic factor affecting the process of plastic working. Analyzing that influence in individual die fragments, allows to engineer the flow of shaped material. The QForm3D commercial program for finite element method calculations was used for numerical simulations. The paper presents multi-variant analysis of forging process with the usage of numerical simulation, which provided many valuable information concerning changes of key parameters, such as: temperature, stress and strain distribution and variations of technological parameters, as well as their mutual influence, difficult to obtain in analysis of industrial process. [ABSTRACT FROM AUTHOR]

We describe a new method for presenting and interpreting linear trends in health inequalities, and present a proof-of-concept analysis of inequalities in smoking among adolescents in Europe. We estimated the regression line of the assumed linear relationship between smoking prevalence in low– and high–socioeconomic status (SES) youth over time. Using simulation, we constructed a 95% confidence interval (CI) for the smoking prevalence in low-SES youth for when this would be 0% in high-SES youth, and we calculated the likelihood of eradicating smoking inequality (<5% for both low and high SES). This method was applied to data on adolescents aged 15–16 years (n  = 250,326) from 23 European countries, derived from the 2003–2015 European Survey Project on Alcohol and Other Drugs. Smoking prevalence decreased more slowly among low- than among high-SES adolescents. The estimated smoking prevalence was 9.4% (95% CI: 6.1, 12.7) for boys and 5.4% (95% CI: 1.4, 9.2) for girls with low SES when 0% with high SES. The likelihood of eradicating smoking inequality was <1% for boys and 37% for girls. We conclude that this novel methodological approach to trends in health inequalities is feasible in practice. Applying it to trends in smoking inequalities among adolescents in Europe, we found that Europe is currently not on track to eradicate youth smoking across SES groups. [ABSTRACT FROM AUTHOR]

Digitalization and circular economy (CE) principles are crucial to 21st century organizations, wherein the management approach can function as a strategic lever. The main gap in the field is related to the position of digitalization in the waste management process, with a concentration on soft computing approaches in developed and developing countries. Actually, the steps of digitalization implementation in the waste management supply chain are evaluated in this research item as a review study. This study uses VOS viewer to analyze scientometrics to examine digitalization in waste management. The article pioneer's simulation methods showcasing digitalization and the circular economy in waste management. Digital technology fosters CE goals, vital for sustainable waste practices. In the subsequent discourse, an examination of the ramifications engendered by the process of digitalization for both the environment and the economy within the framework of the CE is presented. The fourth component of this comprehensive review develops simulation methods to demonstrate digitalization in waste management. The results of this research demonstrated that digitalization integrates Internet of Things (IoT). sensors, optimizes waste management efficiency, and aids decision-making. Route optimization and energy efficiency enhance sustainability in waste management. [Display omitted] • Systematic review of digitalization in waste management: Circular Economy aspect. • MATLAB simulation for waste reduction strategy analysis. • Statistical evaluation: Market size analysis for digitalization in waste management. • Energy management via digitalization simulation in waste processing. [ABSTRACT FROM AUTHOR]

Both regression modeling and clustering methodologies have been extensively studied as separate techniques. There has been some activity in using regression-based algorithms to partition a data set into clusters for classical data; we propose one such algorithm to cluster interval-valued data. The new algorithm is based on the k-means algorithm of MacQueen (1967) and the dynamical partitioning method of Diday and Simon (1976), with the partitioning criteria being based on establishing regression models for each sub-cluster. This also depends on distance measures between the underlying regression models for each sub-cluster. Several types of simulated data sets are generated for several different data structures. The proposed k-regressions algorithm consistently out-performs the k-means algorithm. Elbow plots are used to identify the total number of clusters K in the partition. The new method is also applied to real data. [ABSTRACT FROM AUTHOR]

Fire whirls are a particular case of flame behaviour characterized by a rotating column of fire driven by intense convective heating of air close to the ground. They typically result in a substantial increase in burning rate, temperature, and flame height. Fire whirls can occur in any intense flame environment, including urban areas, particularly within combustible structures, and in wildland or forest fires. Recently, investigations on the creation of fire whirls have attracted much attention. However, most analyses are focused on fire whirl structure, formation, and controlling their unique state. In effect, revisiting the available experimental techniques and numerical simulations used in analyzing fire whirls has received less attention. In this paper, experimental arrangements including empirical set ups and employed fuels are presented in detail. Subsequently, major research progress focused on experimental studies and their laboratory setup is fully discussed, followed by the available numerical simulations, including combustion and turbulence models. Applied methodologies and chosen software in the recent numerical studies are also reviewed exclusively. Finally, the latest findings are featured, and prospective pathways are advised. [ABSTRACT FROM AUTHOR]

• Incomplete-block designs have rarely been used with rapid, holistic methods. • Free linking and free sorting are evaluated in 2 studies with incomplete blocks. • Novel, graph-based simulation is developed for application with incomplete blocks. • In Study 1, "incomplete" linking results are stable, comparable to "complete" • In Study 2, "incomplete" linking is more discriminating and stable than incomplete sorting. As rapid, holistic methods for similarity and description—such as sorting and projective mapping—have grown in popularity, a limiting factor is the number of samples that can be presented to subjects: more than 25 food samples decreases the quality and stability of results. While incomplete-block designs could address this, their use has not been developed for these holistic methods. In this paper we present an empirical investigation into the use of incomplete-block designs with free sorting and the newer free linking. We compare these two methods because while their results are comparable, the cognitive tasks are different, and thus their suitability for incomplete-block designs may differ. We evaluated the effects of incomplete-block designs in two studies. In Study 1, 20 subjects evaluated 6/10 chocolate bars by free linking in an incomplete-block design, with each subject completing 2 blocks; results were compared to a complete-block evaluation of the 10 bars by free sorting and free linking. In Study 2, a total of 90 subjects evaluated 62 terms from a chocolate flavor-wheel in 3 conditions (between subjects): free sorting with complete blocks (N = 30, all 62 terms) and free sorting (N = 30) or free linking (N = 30) with 3 incomplete blocks of 16/62 terms. We introduce a novel method to evaluate stability for the incomplete-block designs that we call "pairwise simulation." From Study 1, we find that pairwise simulation provides adequate stability estimates and that, with sufficient pairwise cooccurrences, free linking with incomplete blocks produces results that are comparable to free sorting or linking with complete blocks. From Study 2, we demonstrate that free linking with incomplete blocks can produce high quality results from a large sample set, maintaining the increased discrimination capacity that marks free linking in general, and that with incomplete blocks, free linking is likely to be more stable than free sorting. This research demonstrates that incomplete-block designs can be used with free linking, and also provides a new, effective method through pairwise simulation for evaluating stability with incomplete-block designs, which cannot be resampled using standard bootstrapping approaches. [ABSTRACT FROM AUTHOR]

Much work has shown that, at all levels, Black citizens tend to be descriptively underrepresented in government. We take up the question of Black descriptive representation at the level of the county legislature, gathering data on the composition of North Carolina's 100 county commissions. We propose an alternative measure of descriptive representation, termed "seats above expectation", and apply a counterfactual simulation approach to gauge the effects of at-large and ward-based elections. We find that Black citizens are underrepresented statewide: there are four fewer Black county commissioners than we would expect, based on the current county board sizes, demographics, and institutional arrangements. However, we find that universal implementation of ward-based elections would increase the statewide total of Black county commissioners by 20 in expectation, a 17% increase over the baseline. Because our methodological approach does not require a natural experiment or policy change, scholars can estimate average treatment effects (ATEs) of ward-based elections on minority descriptive representation across a wider array of locales. [ABSTRACT FROM AUTHOR]

According to the concept of limit-state margin probability function, a new look-ahead learning function called stepwise margin reduction (SMR) is proposed for active learning reliability analysis. SMR aims to select the best next point as the one minimizing, in expectation, the integrated margin probability function when adding such a new point. The plain definition of SMR involves a double integral, and three-fold contributions are made to reducing the associated computational burden. First, the closed-form expression of inner integral is well deduced, which avoids burdensome Gaussian–Hermite quadrature or drawing simulations of Gaussian process. Second, thanks to the locality of analytical expression of inner integral, truncated-integral scheme (TIS) is devised for the outer integral to avoid serious computer memory issue. Third, the candidate pool is pruned to accelerate the selection of best next point per iteration. The efficacy of SMR-based active learning reliability method is illustrated on two analytical functions, three numerical examples and one real-world engineering problem. Results demonstrate that in SMR, the TIS performs better than the traditional limited-integral scheme. Then, in comparison with existing pointwise and look-ahead learning functions, SMR gains favorable advantage in term of both computational accuracy and efficiency. • A learning function called stepwise margin reduction (SMR) is proposed. • The computation of SMR is in a very time-saving manner. • The candidate pool is pruned to accelerate SMR-based adaptive enrichment process. • SMR shows advantage over both existing pointwise and integral learning functions. [ABSTRACT FROM AUTHOR]

Reliability-based design optimization (RBDO) is an active field of research with an ever increasing number of contributions. Numerous methods have been proposed for the solution of RBDO, a complex problem that combines optimization and reliability analysis. Classical approaches are based on approximation methods and have been classified in review papers. In this paper, we first review classical approaches based on approximation methods such as FORM, and also more recent methods that rely upon surrogate modelling and Monte Carlo simulation. We then propose a generalization of the existing surrogate-assisted and simulation-based RBDO techniques using a unified framework that includes three independent blocks, namely adaptive surrogate modelling, reliability analysis, and optimization. These blocks are non-intrusive with respect to each other and can be plugged independently in the framework. After a discussion on numerical considerations that require attention for the framework to yield robust solutions to various types of problems, the latter is applied to three examples (using two analytical functions and a finite element model). Kriging and support vector machines regression together with their own active learning schemes are considered in the surrogate model block. In terms of reliability analysis, the proposed framework is illustrated using both crude Monte Carlo and subset simulation. Finally, the covariance matrix adaptation-evolution scheme (CMA-ES), a global search algorithm, or sequential quadratic programming (SQP), a local gradient-based method, is used in the optimization block. The comparison of the results to benchmark studies shows the effectiveness and efficiency of the proposed framework. [ABSTRACT FROM AUTHOR]

We propose a simple approach to simulate the convergence and the performance of high-speed serial interfaces with adaptive equalization. Such a method uses as input the pulse response of the channel (printed circuit board and cables, plus package/socket) that is then modified by adaptive techniques implementing feed-forward, decision-feedback, and linear-continuous time equalization. Probabilistic considerations are used in this novel method to estimate the evolution during time of the LMS loop and the resulting evolution of the eye diagram. Sample results are reported for a realistic link operating at 20 Gb/s. [ABSTRACT FROM AUTHOR]

Abstract The performance of continuous conveyor systems based on belt conveyors depends on their reliable and trouble-free operation. The most common failures encountered during their operation are mainly those directly related to the conveyor belt itself. However, this is not the only case that may cause their operation to be interrupted. A breakdown may also result from increased wear of the belt conveyor itself. Such systematic failure occurrence then greatly manifests itself in the reduced uptime of the entire belt conveyor. One of the effective solutions to the given problem is to make predictions of their emergence using dynamic models. By appropriately modified dynamic belt conveyor models, it is possible to quickly and accurately establish and predict the cause and location of the conveyor drive wear. This paper presents the belt drive upgrade has been verified under operating conditions. Trouble-free operation time, during which the online belt conveyor's technical condition was monitored, has increased 6 times in comparison to the original life of the drive. Highlights • Using simulation methods to identify causes of failure of belt conveyor drive • On-line conveyor belt condition monitoring post upgrade • 6-fold increase in the belt conveyor trouble-free operation [ABSTRACT FROM AUTHOR]

The paper refers to the dynamic short-term response analysis of the Baltic steel drilling platform (see Fig.2) in a random sea-state represented by one-dimensional wave spectrum proposed by Striekalov and Massel, which is recommended for the Baltic Sea area. The Baltic drilling platform is a jack-up type platform for the exploration and exploitation of oil under the Baltic Sea. The presented analysis deals with the stationary phase of the platform life when its legs are fixed in the sea bottom. The submerged elements of jack-up platforms are relatively slender, thus to assess the in-line wave forces a modified Morison equation is justified. The application of frequency transfer functions to offshore vibration systems leads to structural response spectra whose input is defined by the wave elevation and wind velocity spectra. The analysis can be applied also to support structures for offshore wind turbines. [ABSTRACT FROM AUTHOR]

The paper deals with sensitivity and reliability applications to numerical studies of an off-shore platform model. Structural parameters and sea conditions are referred to the Baltic jack-up drilling platform. The sudy aims at the influence of particular basic variables on static and dynamic response as well as the probability of failure due to water waves and wind loads. The paper presents the sensitivity approach to a generalized eigenvalue problem and evaluation of the performace functions. The first order time-invariant problems of structural reliability analysis are under concern. [ABSTRACT FROM AUTHOR]

Switchgear is an important power system protection equipment. Internal overheating of high-current switchgear has become the most common problem in the power system. In this paper, two different methods of simulation model are adopted to study the temperature rise issues of the 12-kV medium voltage switchgear. First, the electromagnetic field is calculated by using ANSYS APDL, then coupling with fluid dynamics software CFX to give the temperature and flow field distribution of the switchgear. Second, FLUENT and Maxwell 3-D are used to get the temperature and flow field distribution. It can be proven that CFX simulation of flow field is more suitable for the complex models. In the meantime, it has huge differences with FLUENT software when the temperature rise of the switchgear is calculated. In this paper, the influences of inlet velocity, the number of ventilation holes, and their positions are further studied, which could provide theoretical guidance for reducing temperature rise of the switchgear. [ABSTRACT FROM PUBLISHER]

The paper presents the methodology for determining the components which are related to heel of bulk carrier with one component excluded -- the heel of vessel due to waves. The described method was applied to the system, which is dedicated to use in determination of UKC of vessels at the approach to the Port of Swinoujscie. The method includes determination of heel caused by: draught reading errors, wind, current, tugboats and heel related to vessel maneuvers. To determine heel related to vessel maneuver 2-stage method was carried out. The first stage simulation was used to identify the parameters of ship movement. At the second stage, the maximum heel of Bulk Carrier were calculated by using analytical methods. Presented method was implemented to the item rating under keel clearance at the approach to the Port of Swinoujscie. [ABSTRACT FROM AUTHOR]

This paper studies how the selection of the metal price process used and the choice of selected other modeling assumptions affect the value of a metal mining company's mining asset portfolio. We compare results from when metal prices are assumed to be independent of each other, correlated with each other, and correlated with an external factor. These studies are carried out by using the geometric Brownian motion-based and mean-reverting metal price processes. What is also studied is the effect caused by replacing one of the portfolio metals with a typically counter cyclic metal, in this case gold. Numerical simulation analysis is made to study these issues. The results highlight the importance of correctly selecting the price processes used and corroborate some earlier findings on the topic, while also highlighting the effects of process and other modeling choices on (real) option valuation. [ABSTRACT FROM AUTHOR]

Agricultural land is a major source of phosphorus (P) loss, and artificial drainage is one of the pathways for phosphorus transport. In this paper, we reviewed the methods and equations related to phosphorus loss through subsurface tile drain in water quality models. This review is presented through three topics: subsurface hydrology, fate and transport of phosphorus in soil, and phosphorus transport into tile drains. Major simulation methods and some recent updates are reviewed, and calculations in specific models are presented. Nine existing water quality models (ADAPT, ANIMO, APEX, EPIC, HYDRUS, ICECREAM, MACRO, PLEASE, SWAP) can be used to simulate P transport to tile drainage, where three of them (HYDRUS, MACRO, SWAP) do not have a specific phosphorus module but P can be simulated using a general chemical module. Models that are not suitable for simulating fate and transport of P to tile drains under their current status, for example, AnnAGNPS, DRAINMOD, GLEAMS, RZWQM2, SurPhos, SWAT, are also reviewed due to their strength in one of the aspects: subsurface drainage or P dynamics. Based on the methods used in those models, ICECREAM could be the most current comprehensive model for P loss through tile drains from agricultural fields. [ABSTRACT FROM AUTHOR]

We present details of a blended quantum molecular dynamics scheme, utilizing both the canonical and isobaric-isothermal ensembles, in order to not only circumvent the need for any experimental input data ordinarily required for simulations involving the strictly canonical ensemble, but also minimize the relatively high extra computational cost imposed by the increased cutoff energy necessary to avoid the so called Pulay stress error while performing isobaric-isothermal ab initio molecular dynamics simulations using plane-wave basis set. We compare the results of the blended and canonical schemes via the simulated quench of the damage-tolerant Zr 61 Ti 2 Cu 25 Al 12 (ZT1) alloy to below its glass transition temperature. There were subtle differences in structural evolution between the two schemes. Notably, the blended scheme generates a more efficiently packed structure, which is feasibly permitted due to the volume changes that transpire as a result of incorporating a parallel NPT component. Further, while the blended scheme obviates the need for any experimental input data, it is shown that the starting volume is not particularly critical and the computed final density of the alloy is within ∼1% of the reported experimental value of 6.43–6.50 g/cm 3 . Furthermore, the blended scheme demonstrated a greater degree of transformation in the coordination number compared with the canonical, which remains relatively static. The final value of 12.97 obtained from the blended scheme is closer to the ideal of 13.33 as per close-packing theory, a feature that appears to be related to the evolution of a more complex family of Voronoi polyhedra relative to the icosahedral dominant motifs present in the canonical scheme. Furthermore, in both schemes, the partial coordination number in the Zr species, being the primary constituent, demonstrates a plateau in its evolution, but which commences in the blended scheme at a temperature approximately 300 K closer to the reported glass transition temperature. The findings suggest a more reliable and an optimally efficient method for implementing ab initio molecular dynamics in the simulation of complex alloys. [ABSTRACT FROM AUTHOR]

Topology optimization is traditionally framed in a static and deterministic setting notwithstanding the uncertain dynamic nature of many problems. This paper presents a new data-driven simulation-based framework for the effective topology optimization of uncertain and dynamic wind-excited tall buildings. The performance of the system is described through probabilistic performance integrals that encapsulate state-of-the-art performance-based design driven by climatological, aerodynamic and fragility data sets for describing the site-specific hazard, aerodynamic response and damage susceptibility of the system. To solve the resulting probabilistic topology optimization problem, a sequential optimization strategy is developed that is based on solving a series of high quality approximate sub-problems. A suite of case studies demonstrate the effectiveness of the approach. [ABSTRACT FROM AUTHOR]

This paper presents a methodology for determining the components related to the heel of liquefied natural gas (LNG) carriers, excluding the heel of the vessel due to waves. The described method was applied to the description of under keel clearance of vessels approaching the outer port of Świnoujście. The method includes the determination of heel components caused by: draught reading errors, wind, current, tugboats and vessel maneuvers. Determination of the last component was carried out using a 2-stage method. In the first stage, simulation methods were used to identify the parameters of ship movement. In the second stage, the maximum heel of LNG carriers was calculated by analytical methods. [ABSTRACT FROM AUTHOR]

The efficiency of different probabilistic methodologies for the safety assessment of short span railway bridges is compared in the current paper. Two different simulation methods, namely the Monte Carlo and the Latin Hypercube, are combined with two different procedures to enhance the efficiency of the assessment. One of the methods is a tail modelling approach based on the extreme value theory that uses the Generalized Pareto Distribution to model the tail of the obtained distribution. The other one is an Enhanced Simulation procedure which uses an approximation procedure based on the estimates of the failure probabilities at moderate levels for the prediction of the far tail failure probabilities by extrapolation. A composite bridge with six simply supported spans of 12 m and ballasted track is selected as case study for the crossing of the TGV-double high-speed train. The variability of parameters related to the bridge, the track and the train is taken into account along with the existence of track irregularities. The running safety of trains due to loss of contact between the wheel and the rail and the track instability due to excessive deck vibrations are the two safety criteria analyzed, providing examples of limit state functions with different degrees of complexity. The obtained results are extremely promising and indicate the feasibility of the application of this type of methodology in common practice due to the very reasonable computational costs that are required. [ABSTRACT FROM AUTHOR]

Nowadays, HCPV (high concentrator photovoltaics) is largely based on high efficiency MJ (multi-junction) solar cells. Hence, the prediction of the electrical parameters of MJ solar cells is crucial for designing and evaluating the performance of this emerging technology. At the same time, the analytical modelling of the I–V parameters of these devices is complex due to their strong and complex dependence with irradiance, spectrum and cell temperature. In this work, the possibility of predicting the main electrical characteristics of a MJ solar cell by using artificial intelligent techniques is analysed. In particular, three artificial neural network (ANN)-based models were developed: one for simulating the short-circuit current (I sc ), one for simulating the open-circuit voltage (V oc ) and for simulating the maximum power (P max ). The models were developed and evaluated with the data of a lattice-matched GaInP/GaInAs/Ge triple-junction operating at a wide range of conditions. Results show that the models accurately estimate the main electrical parameters of a MJ solar cell under different concentrated sunlight, spectral irradiance and cell temperature with a RMSE (root mean square error) lower than 0.5% and a MBE (mean bias error) almost 0%. [ABSTRACT FROM AUTHOR]

There is increasing interest in the evaluation of the capability of power-electronic-interfaced distributed generators (DGs) connected to weak medium-voltage (MV) feeders, to provide ancillary services. Classic simulations using simplified DG models have their limitations and may prove insufficient due to the complexity of adequate modeling of power electronic interfaces. Moreover, conventional testing does not allow the investigation of the real generator with the distribution system interactions. Therefore, a scaled-down physical DG (i.e., inverter and dc source) with exactly the same functionalities can be used to evaluate the network integration of the actual DG, by means of power hardware-in-the-loop (PHIL) testing. In this paper, suitable scaling of the power rating and voltage level of the hardware is performed, and an interfacing approach is proposed that achieves stability of simulations without compromising accuracy. The PHIL tests successfully demonstrate potential problems in the coordination of the on-load tap changer controlling the MV feeder with the voltage controller of the DG, such as recurring tap changes, increased reactive power flows, and opposing actions. Moreover, recurring oscillations of the voltage controller of the hardware model are observed at certain system configurations. These inverter control instabilities, which are not visible in purely digital simulations, demonstrate the added value of employing PHIL testing for current and future power system analysis and testing. [ABSTRACT FROM PUBLISHER]

This work explores the feasibility of using advanced simulation-based methods for reliability sensitivity analysis of nonlinear structural systems subject to stochastic excitation. Reliability is defined in terms of a first excursion probability which measures the chances that uncertain structural responses exceed in magnitude prescribed threshold levels within a specified time interval. The proposed reliability sensitivity analysis consists of applying a simple post-processing step associated with an advanced sampling-based reliability analysis. It does not require any additional system response evaluations. In addition, the method provides information about the whole trend of the reliability sensitivity estimates in terms of the threshold levels. The approach is validated on two nonlinear structural models under stochastic ground excitation. [ABSTRACT FROM AUTHOR]

The paper presents the Spectral Representation Theorem of a stationary process and two simulation methods derived from it. In order to test the accuracy of the two simulation methods two numerical applications are employed. First, using a theoretical power spectral density (PSD), two sets of sample functions, corresponding to each method, are generated and a comparison of the obtained numerical results with the analytical PSD is carried out. The second example is more complex and consists in using the stationary zone of the strong motion of the recorded NS acceleration registered at INCERC during the 1977 Vrancea earthquake. The corresponding Fourier Spectrum is calculated. In order to obtain a smoother PSD representation for the real Fourier spectrum, a specific barrier model spectrum (SBM) is fitted to it and the corresponding PSD calculated. This PSD is used to generate two sets of samples. The mean PSD obtained using both methods of simulation is compared with that characterizing the registered acceleration. The paper shows that the generated time series possess all the theoretical probabilistic characteristics discussed below, when the number of terms used in the simulation formulas is large. Three types of estimators are employed in the numerical evaluation of both simulation methods [ABSTRACT FROM AUTHOR]

Agent-based modeling has become increasingly popular in recent years, but there is still no codified set of recommendations or practices for how to use these models within a program of empirical research. This article provides ideas and practical guidelines drawn from sociology, biology, computer science, epidemiology, and statistics. We first discuss the motivations for using agent-based models in both basic science and policy-oriented social research. Next, we provide an overview of methods and strategies for incorporating data on behavior and populations into agent-based models, and review techniques for validating and testing the sensitivity of agent-based models. We close with suggested directions for future research. [ABSTRACT FROM PUBLISHER]

This paper presents assumptions and process of the forming of a risk assessment model for collision between a passenger ferry departing from or approaching port of Świnoujście and a chemical tanker carrying a dangerous cargo. In order to assess navigational safety on the basis of data obtained from AIS system, were prepared probabilistic domains of ships, which made it possible to estimate number of navigational incidents as well as their spatial distribution, that consequently allowed to determine potentially dangerous areas. The next phase was formulation of a simulative model intended for the calculating of probability of collision between the ferry and chemical tanker as well as the determining of characteristic scenarios for such collision. This paper presents also an analysis of consequences of the collision with taking into consideration a damage of cargo tanks. [ABSTRACT FROM AUTHOR]

Cloud Analysis is based on simple regression in the logarithmic space of structural response versus seismic intensity for a set of registered records. A Bayesian take on the Cloud Analysis, presented herein, manages to take into account both record-to-record variability and other sources of uncertainty related to structural modelling. First, the structural response to a suite of ground motions, applied to different realizations of the structural model generated through a standard Monte Carlo, is obtained. The resulting suite of structural response is going to be used as 'data' in order to update the joint probability distribution function for the two regression parameters and the conditional logarithmic standard deviation. In the next stage, large-sample MC simulation based on the updated joint probability distribution is used to generate a set of plausible fragility curves. The robust fragility is estimated as the average of the generated fragility curves. The dispersion in the robust fragility is estimated as the variance of the plausible fragility curves generated. The plus/minus one standard deviation confidence interval for the robust fragility depends on the size of the sample of 'data' employed. Application of the Bayesian Cloud procedure for an existing RC frame designed only for gravity-loading demonstrates the effect of structural modelling uncertainties, such as the uncertainties in component capacities and those related to construction details. Moreover, a comparison of the resulting robust fragility curves with fragility curves obtained based on the Incremental Dynamic Analysis shows a significant dependence on both the structural performance measure adopted and the selection of the records. [ABSTRACT FROM AUTHOR]

Magnetic fluid was a novel functional material with many unique properties, especially in the case that the magnetic field was applied. It was found that the special properties of magnetic fluid were determined by its unique microstructure. Then, the special properties could be understood fundamentally by researching the extraordinary nature of the microstructure of the magnetic fluid. At the same time, it was a good theoretic guidance for the experimental research on the properties of magnetic fluid to make clear about the microstructure model theoretically. Therefore, it was particularly important to study the simulation methods to obtain the microstructure of magnetic fluid. The development of the microstructure simulation methods of magnetic fluid were introduced in this article, and the basic principles of various simulation methods were expounded in detail. The features of each microstructure simulation methods of magnetic fluid were summarized and compared with each other. Finally, the key problems and research direction of the numerical simulation method in the future were described. [ABSTRACT FROM AUTHOR]

Abstract: This work explores the effect of using updated robust reliability measures in the context of stochastic structural dynamical systems. A Bayesian probabilistic methodology for model updating is first implemented for the purpose of updating the structural model using dynamic data. The updated distribution of the system model parameters is then used to implement a strategy for updating the system reliability. The effect of the updated information on the robust performance and design of dynamical systems under stochastic excitation and modeling uncertainty is illustrated by several example problems. [Copyright &y& Elsevier]

Methods for the experimental simulation of equivalent operating loading conditions in the basic ranges of working medium parameters (pressure, temperature, aggregative state) have been developed. The experimental test jigs and computational-experimental base created allowed us to carry out studies of the stress-strain state and fracture kinetics of pipe elements under conditions simulating thermomechanical load spectra to diagnose the real state of pipelines and to estimate the remaining life from functional fitness indices. [ABSTRACT FROM AUTHOR]

The paper presents analytical and Monte Carlo simulation methods applied to the reliability evaluation of a system operating at two different operation states. A semi-Markov process is applied to construct the system operation model and its main characteristics are determined. Analytical linking of this operation model with the system reliability model is proposed to get a general reliability model of the system operating at two varying operation conditions and to find its reliability characteristics. The application of Monte Carlo simulation based on this general model to the reliability evaluation of this system is proposed as well. The results obtained from those two considered methods are evaluated. [ABSTRACT FROM AUTHOR]

It is important to realize good consistency among different device units on a big wafer. The bad product consistency results from the processing deviation which is hard to control. A novel simulation method to control and reduce the influence of processing deviation on the sensitivity of a piezoresistive pressure sensor is provided in this paper. Based on finite element analysis (FEA) and mathematical integration, the performance of the pressure sensors is simulated. The pressure sensors are designed and fabricated according to the simulation results. The test results confirm that this simulation method can help to design the pressure sensor very precisely. From the simulation and test results, we find that properly enlarging the size of the square silicon membrane can improve the devices consistency. [ABSTRACT FROM AUTHOR]

Abstract: This paper compares the simulation results of three methods of using the commercial finite element package ABAQUS to model the very large deflection behaviour of steel structures with realistic endplate joints in fire. The results of a set of fire tests on restrained steel beam–column assemblies were used to check the accuracy of these different modelling methods. In the first modelling method, the fire exposed structural members, including the connections, were simulated using detailed solid elements to enable detailed behaviour of the structure to be faithfully represented. In the second method, the unexposed segments of the columns were represented by conventional line (beam) elements, the joints were represented using springs (Connector Elements) based on the component based method, and the beam was modelled using solid elements. In the third method, the joints were modelled using springs as in the second method and the beam and columns were simulated using line (beam) elements. As expected, the detailed simulation method was extremely time-consuming, but was able to produce accurate results. The simulation results from the second and third methods contained some inaccuracy, but depending on the simulation objective, their simulation results may be acceptable. In particular, the third simulation method was very efficient, suitable for simulating complete frame structures under very large deflections in fire. This paper will compare results from the three different simulation methods for different parts of the structure, including the fire exposed beam, the connection components and the columns, through different stages of fire exposure, from initial exposure to fire to the development of catenary action in the beam. From these comparisons of simulation results, this paper will recommend appropriate methods of modelling steel framed structures with realistic joints for different design objectives. [Copyright &y& Elsevier]

Abstract: We propose a numerical method for resummation of perturbative series, which is based on the stochastic perturbative solution of Schwinger–Dyson equations. The method stochastically estimates the coefficients of perturbative series, and incorporates Borel resummation in a natural way. Similarly to the “worm” algorithm, the method samples open Feynman diagrams, but with an arbitrary number of external legs. As a test of our numerical algorithm, we study the scale dependence of the renormalized coupling constant in a theory of one-component scalar field with quartic interaction. We confirm the triviality of this theory in four and five space–time dimensions, and the instability of the trivial fixed point in three dimensions. [Copyright &y& Elsevier]

Abstract: This paper summarizes currently used techniques for simulation and computer-aided design in electron and ion beam optics. Topics covered include: field computation, methods for computing optical properties (including Paraxial Rays and Aberration Integrals, Differential Algebra and Direct Ray Tracing), simulation of Coulomb interactions, space charge effects in electron and ion sources, tolerancing, wave optical simulations and optimization. Simulation examples are presented for multipole aberration correctors, Wien filter monochromators, imaging energy filters, magnetic prisms, general curved axis systems and electron mirrors. [Copyright &y& Elsevier]

In the last decade the importance of transmission electron microscopic studies has become increasingly important with respect to the characterization of organic materials, ranging from small organic molecules to polymers and biological macromolecules. This review will focus on the use of transmission electron microscope to perform electron crystallography experiments, detailing the approaches in acquiring electron crystallographic data. The traditional selected area approach and the recently developed method of automated diffraction tomography (ADT) will be discussed with special attention paid to the handling of electron beam sensitive organic materials. [ABSTRACT FROM AUTHOR]

This paper shows a new hybrid method for risk assessment regarding interruptions in sensitive processes due to faults in electric power distribution systems. This method determines indices related to long duration interruptions and short duration voltage variations (SDVV), such as voltage sags and swells in each customer supplied by the distribution network. Frequency of such occurrences and their impact on customer processes are determined for each bus and classified according to their corresponding magnitude and duration. The method is based on information regarding network configuration, system parameters and protective devices. It randomly generates a number of fault scenarios in order to assess risk areas regarding long duration interruptions and voltage sags and swells in an especially inventive way, including frequency of events according to their magnitude and duration. Based on sensitivity curves, the method determines frequency indices regarding disruption in customer processes that represent equipment malfunction and possible process interruptions due to voltage sags and swells. Such approach allows for the assessment of the annual costs associated with each one of the evaluated power quality indices. [ABSTRACT FROM AUTHOR]

Abstract: The contribution presents results of computer simulations describing the interaction between a low-temperature multicomponent plasma and an immersed metal substrate. For this purpose two models were prepared. The first model is designed to follow the volume processes in oxygen-containing electronegative plasma. The technique used was the macroscopic kinetic approach with a kinetic scheme consisting of more than 100 reactions. As a result, the concentrations of individual charged species for various discharge parameters were derived. These species are used as input parameters in the second model based on the Particle-in-Cell–Monte Carlo Collision (PIC–MCC) particle simulation technique. The sheath structure of the multicomponent plasma containing more than one type of negative as well as positive ions and the fluxes of individual charged species impinging the oxidized substrates were studied with the help of this model. [Copyright &y& Elsevier]

This article presents the partial results obtained in the implementation of a simulation and visualization platform, to support the analysis and decision making processes in urban mobility projects. The possibility to represent pathologies in road infrastructure and the actors behaviour, allows the potential application in scenarios of Latin-American cities. These results are briefed in the following topics: simulation and visualization model, simulation and visualization applications. [ABSTRACT FROM AUTHOR]

The felge, or undersomersault, on parallel bars has become an important skill in men's artistic gymnastics as it forms the basis of many complex variations. To receive no deductions from the judges, the felge must be performed without demonstrating the use of strength to achieve the final handstand position. Two male gymnasts each performed nine trials of the felge from handstand to handstand while data were recorded using an automatic motion capture system. The highest and lowest scoring trials of each gymnast, as determined by four international judges, were chosen for further analysis. The technique used by each gymnast was optimized using a computer simulation model so that the final handstand position could be achieved with straight arms. Two separate optimizations found different techniques identified in the coaching literature that are used by gymnasts. Optimum simulations resulted in improved performances through a combination of increased vertical velocity and height of the mass centre at release. Although the optimum technique found close to the gymnasts' own technique was more demanding in terms of the strength required, it offered the potential for more consistent performance and future developments in skill complexity. [ABSTRACT FROM AUTHOR]

• Activated sludge models were helpful to provide directions for experiment research. • DO concentrations required for NOB repression were lower at higher SRTs. • DO and SRTs required for NOB repression were lower at lower temperatures. • Stable partial nitrification could be achieved with effluent recycling. At present, sustainable and stable partial nitrification has not been widely achieved in the mainstream PN/ANAMMOX process. Here, the feasibility of sustainable and stable partial nitrification was demonstrated in automatic recycling PN/ANAMMOX reactor under mainstream conditions using both simulation and experimental methods. Stable nitrite accumulation in the aerobic zone could be achieved via regulating dissolved oxygen (DO) concentrations and sludge retention time (SRT). The DO concentrations required for the repression of nitrite-oxidizing bacteria (NOB) were lower at longer SRTs. The DO concentrations and SRTs required for NOB repression were lower at lower temperatures. However, NOB repression was diminished by a persistent low DO and short SRT under mainstream conditions. With the introduction of automatic recycling, sustainable and stable partial nitrification was achieved. Effluent recycling could limit the nitrite-nitrogen required for NOB growth. Collectively, effluent recycling may serve as a feasible and useful strategy for NOB inhibition during the PN/ANAMMOX process. [ABSTRACT FROM AUTHOR]

This paper proposes a new test procedure called the rel test to resolve the problem of small-sample local biasedness and non-monotonic power behavior of the Wald test for two linear restrictions caused by inaccuracy of the estimated covariance matrix of the estimator. This new test procedure, which does not need the covariance matrix of the estimator, involves finding the critical region based on contour points of the percentile confidence limit of a rel utilizing the bootstrap in order to obtain a test with the desired size and good power properties. Simulation results indicate that this new test procedure, the rel test, performs rather well both with respect to controlling size and having monotonic increasing power. [ABSTRACT FROM AUTHOR]

This paper introduces a new class of numerical schemes for the pathwise approximation of solutions of stochastic differential equations (SDEs). The proposed family of strong predictor–corrector Euler methods are designed to handle scenario simulation of solutions of SDEs. It has the potential to overcome some of the numerical instabilities that are often experienced when using the explicit Euler method. This is of importance, for instance, in finance where martingale dynamics arise for solutions of SDEs with multiplicative diffusion coefficients. Numerical experiments demonstrate the improved asymptotic stability properties of the proposed symmetric predictor–corrector Euler methods. [ABSTRACT FROM AUTHOR]

Markowitz's mean-variance (MV) efficient portfolio selection is one of the most widely used approaches in solving portfolio diversification problem. However, contrary to the notion of diversification, MV approach often leads to portfolios highly concentrated on a few assets. Also, this method leads to poor out-of-sample performances. Entropy is a well-known measure of diversity and also has a shrinkage interpretation. In this article, we propose to use cross-entropy measure as the objective function with side conditions coming from the mean and variance-covariance matrix of the resampled asset returns. This automatically captures the degree of imprecision of input estimates. Our approach can be viewed as a shrinkage estimation of portfolio weights (probabilities) which are shrunk towards the predetermined portfolio, for example, equally weighted portfolio or minimum variance portfolio. Our procedure is illustrated with an application to the international equity indexes. [ABSTRACT FROM AUTHOR]