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In response to the problem of poor search performance and difficulty in escaping from the local optimum in the Harris hawks optimizer, an improved Harris hawks optimizer with enhanced logarithmic spiral and dynamic factor (IHHO‐ELSDF) is proposed in this paper. The enhanced logarithmic spiral mechanism is adopted in the exploration phase, and its main feature is the use of an improved opposite‐learning hybrid logarithmic spiral mechanism to search for more promising regions. The dynamic factor is used to replace the escaping energy to improve the global search capability of the algorithm, and it can better balance exploration and exploitation. In addition, a random distribution strategy is proposed for the exploitation phase to avoid falling into the local optimum. Based on 23 classical test functions, the influence of the distribution probability, the three improved mechanisms, and the exploration–exploitation ratio in IHHO‐ELSDF are analyzed. Subsequently, IHHO‐ELSDF is subjected to a comparative analysis with 17 algorithms on the IEEE CEC2022 benchmark suite. These tests show that IHHO‐ELSDF outperforms most competitors in numerical optimization. Furthermore, to assess its applicability in real‐world problems, IHHO‐ELSDF is employed to optimize parameters in the wavelet neural network used for molten iron temperature prediction. The simulation results based on real production data show that the proposed prediction model achieves a high prediction precision with RMSE=6.1305$$ \mathrm{RMSE}=6.1305 $$, R2=0.9322$$ {R}^2=0.9322 $$, and HR=89$$ \mathrm{HR}=89 $$. [ABSTRACT FROM AUTHOR]

Blast loading is characterized as an impact loading with exponential attenuation, while damping serves as an intrinsic parameter that affects the vibration effect of beam members. The linear attenuation for simplified blast loading and undamped situation for beam members is often adopted by most scholars or codes for the calculation of dynamic factors. These assumptions that do not conform to the actual situation can lead to deviations in the results of the dynamic factor. In this study, the implicit solutions for the dynamic factors of both flexible and rigid beam members were derived by the exponential attenuation loading and damping of beam members. The dynamic response verification of an H-shaped steel beam blast test was completed using LS-DYNA software. The comparison calculation of the theoretical solutions of dynamic factors in this paper with the Chinese blast-resistant design code and finite element simulation was carried out. The results show that the dynamic factor will be higher when the blast loading is simplified to linear attenuation loading for undamped beams. The shape parameter of the exponential attenuation loading and the damping ratio of beam members both reduce the effect of the dynamic factor, with the damping ratio having a more significant effect. [ABSTRACT FROM AUTHOR]

This article aims to provide an accurate mathematical model with the minimum number of degrees of freedom for describing the floating sleeper phenomenon. This was accomplished using mathematical modeling supported by extensive field measurements of the railway track. Although the observed phenomenon is very complex, the simplified single degree of freedom (SDOF) mathematical model proved accurate enough for its characterization. The progression of the deterioration of the railway track was successfully correlated to changes in the maximal dynamic factor for different types of pulse loading. The results of the presented study might enable the enhanced construction and maintenance of railroads, particularly in karst areas. [ABSTRACT FROM AUTHOR]

Abstract In response to the problem of poor search performance and difficulty in escaping from the local optimum in the Harris hawks optimizer, an improved Harris hawks optimizer with enhanced logarithmic spiral and dynamic factor (IHHO‐ELSDF) is proposed in this paper. The enhanced logarithmic spiral mechanism is adopted in the exploration phase, and its main feature is the use of an improved opposite‐learning hybrid logarithmic spiral mechanism to search for more promising regions. The dynamic factor is used to replace the escaping energy to improve the global search capability of the algorithm, and it can better balance exploration and exploitation. In addition, a random distribution strategy is proposed for the exploitation phase to avoid falling into the local optimum. Based on 23 classical test functions, the influence of the distribution probability, the three improved mechanisms, and the exploration–exploitation ratio in IHHO‐ELSDF are analyzed. Subsequently, IHHO‐ELSDF is subjected to a comparative analysis with 17 algorithms on the IEEE CEC2022 benchmark suite. These tests show that IHHO‐ELSDF outperforms most competitors in numerical optimization. Furthermore, to assess its applicability in real‐world problems, IHHO‐ELSDF is employed to optimize parameters in the wavelet neural network used for molten iron temperature prediction. The simulation results based on real production data show that the proposed prediction model achieves a high prediction precision with RMSE=6.1305, R2=0.9322, and HR=89.

The present study examined the convergent, structural, and predictive properties of Violence Risk Scale–Sexual Offense version (VRS-SO) scores in a sample of 200 men on community supervision for sexual offenses, attending forensic community outpatient services and followed up an average 8.6 years. The VRS-SO and two additional dynamic sexual recidivism risk measures—STABLE 2007 and Sex Offender Treatment Intervention and Progress Scale (SOTIPS)—were coded archivally from clinic files; Static-99R ratings were extracted. Recidivism data were captured from Royal Canadian Mounted Police records. VRS-SO static, dynamic, and total scores demonstrated expected patterns of convergence with total and subscale scores of the risk measures. Moreover, a confirmatory factor analysis of the VRS-SO dynamic item scores demonstrated acceptable model fit for a correlated three-factor solution consistent with prior confirmatory factor analyses. Discrimination analyses demonstrated that VRS-SO dynamic and total scores and STABLE 2007 scores had large prediction effects for 5-year sexual recidivism (area under the curves [AUCs] =.71–.72) while SOTIPS had a medium effect for this outcome (AUC =.67); the measures yielded medium to large effects for nonsexual recidivism. Cox regression survival analyses demonstrated that VRS-SO dynamic, Sexual Deviance factor, and SOTIPS scores each incrementally predicted sexual recidivism controlling for Static-99R or VRS-SO static factor scores. VRS-SO calibration analyses demonstrated that expected or predicted 5-year sexual recidivism rates showed generally close correspondence to the rates predicted or observed in the present community sample. Results support the psychometric properties of the VRS-SO, a sexual violence risk assessment and treatment planning measure, to a community outpatient sample. Public Significance Statement: The present study demonstrates that key psychometric properties for the Violence Risk Scale–Sexual Offense version, a sexual violence risk assessment and treatment planning tool that was originally developed and validated on institutional samples, extend to a community sample. The results extend the range of assessment options available to evaluators conducting sexual violence risk assessments on community samples. [ABSTRACT FROM AUTHOR]

The focus of this paper is to examine the dynamic factor of the suburban railway by utilizing the random vibration approach. Breaking through the previous methods of relying on huge amounts of measured data, herein, the dynamic factor essentially results from two major parts: the dynamic effect caused by moving train loads and that generated by track irregularity, which has clear physical significance. As the internal excitation of the vehicle–bridge system, track irregularity has strong randomness. Based on the dimension reduction method, the spatial domain power spectral density (PSD) of the track irregularity is transformed into the time-domain PSD. Therefore, the randomness of the random process is reduced by exploiting the constraint form of a random function, and then, the typical samples of the track irregularity considering randomness are constructed. Using the vehicle–bridge coupled vibration model, the standard deviation of the dynamic factor is evaluated accounting for the random track irregularity and 99.7% guarantee rate. Finally, the impact coefficient of the track irregularity on the bridge is methodically obtained. The sensitivity of the standard deviation of the dynamic factor to vehicle speed and bridge frequency is analyzed. The given solution methodology can fully take into account the randomness of the track irregularity. Thereby, it provides the dynamic factor formulas as a reference for the dynamic performance evaluation of suburban railway bridges and possible revision of current design specifications. [ABSTRACT FROM AUTHOR]

Blast loading is characterized as an impact loading with exponential attenuation, while damping serves as an intrinsic parameter that affects the vibration effect of beam members. The linear attenuation for simplified blast loading and undamped situation for beam members is often adopted by most scholars or codes for the calculation of dynamic factors. These assumptions that do not conform to the actual situation can lead to deviations in the results of the dynamic factor. In this study, the implicit solutions for the dynamic factors of both flexible and rigid beam members were derived by the exponential attenuation loading and damping of beam members. The dynamic response verification of an H-shaped steel beam blast test was completed using LS-DYNA software. The comparison calculation of the theoretical solutions of dynamic factors in this paper with the Chinese blast-resistant design code and finite element simulation was carried out. The results show that the dynamic factor will be higher when the blast loading is simplified to linear attenuation loading for undamped beams. The shape parameter of the exponential attenuation loading and the damping ratio of beam members both reduce the effect of the dynamic factor, with the damping ratio having a more significant effect.

Under the background of global warming， summer extreme rainstorm events occurred frequently in Inner Mongolia.As an important ecological security barrier in northern China， the sensitivity of the climate change in this area is increasing.Based on the daily precipitation observation data of National Meteorological Station from 1981 to 2020 and China's first-generation Global Atmospheric Reanalysis product （CRA40）， the variation regularity and dynamic factors of summer extreme rainstorm in Inner Mongolia in the past 40 years were studied.The conclusions are as follows： （1） The spatial distribution of summer precipitation in Inner Mongolia is gradually increasing from west to east， the difference between east and west is obvious， which is closely related to the distribution of the terrain.Hetao area and the southeast of Inner Mongolia are the areas with frequent rainstorm.In the past 40 years， the summer precipitation of most stations in the whole region were decreasing， and the significant decreasing stations of precipitation reached 36.44%.（2） The summer extreme rainstorm in Inner Mongolia mainly occurred in July and August and had obviously interannual variation.The frequency of extreme rainstorm decreased after 2000， but began to increase significantly after 2016.There have been 12 extreme rainstorm processes in the whole region in the past 40 years， which mainly affected the Hetao region in the west and the southeast region of Inner Mongolia.（3）During the extreme rainstorms happened in the Hetao region and the southeast， the large value area of dynamic factor basically coincides with the strong rainfall area， the dynamic factor of the precipitation area in the eastern region is significantly larger than that in the western region.The four dynamic factors had good indicative significance for typical extreme rainstorm process in southeast， but in typical extreme rainstorm process in west， the moist thermodynamic advection factors and the thermodynamic wave activity density performed better.（4） CRA40 reanalysis data showed that during the extreme rainstorm in the western and southeastern regions， the subtropical high was obviously stronger， and 500 hPa was affected by the circulation system with higher east and lower west， obviously water vapor channel was established between them also with significant water vapor convergence.Combined with the remarkable vertical ascending movement and the large value area of generalized potential temperature， meanwhile add the effect of the terrain that both lead to the improvement of precipitation efficiency， the extreme rainstorm events occurred.

In order to meet the needs of refined landslide risk management, the extended correlation framework of dynamic susceptibility modeling desiderates to be further explored. This work considered the Wanzhou channel of the Three Gorges Reservoir Area as the experimental site, with a transportation channel with significant economic value to carry out innovative research in two stages. (i) Five machine learning models logistic regression (LR), multilayer perceptron neural network (MLPNN), support vector machine (SVM), random forest (RF), and decision tree (DT) were used to explore landslide susceptibility distribution based on detailed landslide boundaries. (ii) Based on the PS-InSAR technology, the dynamic factor of deformation intensity was obtained. Subsequently, the dynamic factor was combined with proposed static factors (topography conditions, geological conditions, hydrological conditions, and human activities) to generate dynamic landslide susceptibility mapping (DLSM). The receiver operating characteristic (ROC) curve, accuracy, precision, recall, and F1 score were proposed as evaluation metrics. Compared with ignoring the dynamic factor, the predictive accuracy of some models was further improved when considering the dynamic factor. Especially the DT model, the area under the curve of ROC (AUC) value increased by 2%, and obtained the highest AUC value (93.1%). The susceptibility results of introducing the dynamic factor are more in line with the spatial distribution of actual landslides. The research framework proposed in this study has important reference significance for the dynamic management and prevention of landslide disasters in the study area. [ABSTRACT FROM AUTHOR]

Ossification of the posterior longitudinal ligament (OPLL) has been identified as an important cause of cervical myelopathy. However, the biomechanical mechanism between the OPLL type and the clinical characteristics of myelopathy remains unclear. The aim of this study was to evaluate the effect of different types of OPLL on the dynamic biomechanical response of the spinal cord. A three-dimensional finite element model of the fluid–structure interaction of the cervical spine with spinal cord was established and validated. The spinal cord stress and strain, cervical range of motion (ROM) in different types of OPLL models were predicted during dynamic flexion and extension activity. Different types of OPLL models showed varying degrees of increase in stress and strain under the process of flexion and extension, and there was a surge toward the end of extension. Larger spinal cord stress was observed in segmental OPLL. For continuous and mixed types of OPLL, the adjacent segments of OPLL showed a dramatic increase in ROM, while the ROM of affected segments was limited. As a dynamic factor, flexion and extension of the cervical spine play an amplifying role in OPLL-related myelopathy, while appropriate spine motion is safe and permitted. Segmental OPLL patients are more concerned about the spinal cord injury induced by large stress, and patients with continuous OPLL should be noted to progressive injuries of adjacent level. [ABSTRACT FROM AUTHOR]

Climate change has led to more frequent extreme weather events such as heatwaves, droughts, and storms, which significantly impact agriculture, causing crop damage. Greenhouse cultivation not only provides a manageable environment that protects crops from external weather conditions and pests but also requires precise microclimate control. However, greenhouse microclimates are complex since various heat transfer mechanisms would be difficult to model properly. This study proposes an innovative hybrid model (DF-RF-ANN), which seamlessly fuses three components: the dynamic factor (DF) model to extract unobserved factors, the random forest (RF) to identify key input factors, and a backpropagation neural network (BPNN) to predict greenhouse microclimate, including internal temperature, relative humidity, photosynthetically active radiation, and carbon dioxide. The proposed model utilized gridded meteorological big data and was applied to a greenhouse in Taichung, Taiwan. Two comparative models were configured using the BPNN and the Long short-term memory neural network (LSTM). The results demonstrate that DF-RF-ANN effectively captures the trends of the observations and generates predictions much closer to the observations compared to LSTM and BPNN. The proposed DF-RF-ANN model hits a milestone in multi-horizon and multi-factor microclimate predictions and offers a cost-effective and easily accessible approach. This approach could be particularly beneficial for small-scale farmers to make the best use of resources under extreme climatic events for contributing to sustainable development goals (SDGs) and the transition towards a green economy. [ABSTRACT FROM AUTHOR]

In-service Portland cement concrete (PCC) pavements are subject to repeated dynamic loads from moving vehicles; thus, the actual stress generated in a PCC pavement may significantly differ from the static stress, which is normally used in the design and evaluation of pavement performance. Calculating the stress in PCC pavements under moving vehicle loads is of importance to assess their actual service condition, particularly for pavements with different surface roughness levels as the deteriorated roughness might cause large stress in PCC pavement subject to dynamic loads. In this paper, a method is proposed to compute the dynamic response in terms of loads and stresses generated in jointed plain concrete pavements (JPCPs) under a moving axle load, considering the effects of the pavement surface roughness, the vehicle parameters (including vehicle speeds and axle weights), and the pavement structure parameters (including thickness and elastic modulus of different layers and the existence of dowel bars). The dynamic axle load is firstly generated based on the quarter-car model, running through three successive slabs of which the surface roughness is determined by the power spectral density method, and the critical locations in slabs where the largest tensile stresses occur are identified. The combined effects of various pavement surface roughness levels, vehicle speeds, axle weights, and pavement structure parameters are evaluated in terms of the stress and the dynamic factor defined as the ratio of the tensile stress under dynamic load to the tensile stress under static load. For the roughness level D, the tensile stress can reach a maximum value of 3.13 MPa, and the dynamic factor can reach a maximum value of 2.46, which is much larger than the dynamic factor of 1.15 or 1.2 currently used in design guidebooks. Increasing the thicknesses of pavement slab or the subbase layer is an effective way to reduce the tensile stress in JPCP, while increasing the thickness of base layer is not effective. The results of this study can benefit future pavement design and pavement performance evaluation by providing the actual stress and the useful dynamic factor values for various conditions of field pavements. Moreover, preventive maintenance, particularly the improvement of pavement surface roughness, can be planned by referring to the results of this study, to avoid large tensile stress generated in JPCPs. [ABSTRACT FROM AUTHOR]

Copyright of Plateau Meteorology is the property of Plateau Meteorology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We consider a Gaussian variational approximation of the posterior density in high-dimensional state space models. The number of parameters in the covariance matrix of the variational approximation grows as the square of the number of model parameters, so it is necessary to find simple yet effective parametrisations of the covariance structure when the number of model parameters is large. We approximate the joint posterior density of the state vectors by a dynamic factor model, having Markovian time dependence and a factor covariance structure for the states. This gives a reduced description of the dependence structure for the states, as well as a temporal conditional independence structure similar to that in the true posterior. We illustrate the methodology on two examples. The first is a spatio-temporal model for the spread of the Eurasian collared-dove across North America. Our approach compares favorably to a recently proposed ensemble Kalman filter method for approximate inference in high-dimensional hierarchical spatio-temporal models. Our second example is a Wishart-based multivariate stochastic volatility model for financial returns, which is outside the class of models the ensemble Kalman filter method can handle. [ABSTRACT FROM AUTHOR]

In the stochastic volatility models for multivariate daily stock returns, it has been found that the estimates of parameters become unstable as the dimension of returns increases. To solve this problem, we focus on the factor structure of multiple returns and consider two additional sources of information: first, the stock index associated with the market factor and, second, the realized covariance matrix calculated from high-frequency data. The proposed dynamic factor model with the leverage effect and realized measures is applied to 10 top stocks composing the exchange traded fund linked with the investment return of the S&P 500 index and the model is shown to have a stable advantage in portfolio performance. [ABSTRACT FROM AUTHOR]

Problem. The disadvantage of the existing dependencies for determining the possibility of the automobile drive wheel slip with the maximum use of engine power and indicators of the interaction of the drive wheels with the supporting surface is that they are correct only if the motion of the car is steady. This downside is due to the fact that when deriving the equation of the car motion, the assumption is made that the total tractive force is on the drive wheels, that is, without taking into account the energy losses due to the increase in the kinetic energy of the rotating masses of the engine, transmission, and drive wheels. At the same time, the specified energy losses are compensated by a relative increase in the inertia (mass) of the gradually moving car. Such an assumption is quite correct for determining the traction and speed characteristics of a car not only during steady motion but also during acceleration. Determining the possibility of the automobile drive wheel slip during automobile acceleration, this assumption is incorrect because the drive wheels are not affected by the total tractive force, but by a force that is reduced in accordance with energy losses due to an increase in the kinetic energy of the rotating masses of the engine, transmission, and driving wheels. It is necessary to take into account the reduction of the tractive force on the drive wheels during the acceleration of the car in order to eliminate the mentioned shortcoming. Goal. The aim is the further development of the theory of the car by improving the dependencies that allow determining the conditions for the possibility of the automobile drive wheel slip during its acceleration and the modes of its motion. Methodology. The considered approaches for achieving this aim are based on the laws of physics, theoretical mechanics and provisions of the theory of the car. Results. Analytical dependencies have been improved to determine the conditions for the possibility of the automobile drive wheel slip during its acceleration and the modes of its motion. Dependencies for determining the range of the automobile drive wheel slip on the speed of the vehicle during acceleration are obtained. During the theoretical study of the car motion process, it was established that the developed dependencies allow determining the car driving mode and the possibility of the automobile drive wheel slip both during acceleration and steady motion. Originality. The obtained dependences for determining the possibility of the automobile drive wheel slip during acceleration of the car made it possible to clarify the idea of the driving mode of the car and the possibility of the automobile drive wheel slip both during acceleration and during steady motion. Practical value. The obtained dependencies can be used in the design of new and improved sports cars such as dragsters, and for analyzing the dynamics of the car motion during acceleration with total fuel supply and determining the nature of the interaction of the drive wheels with the supporting surface depending on the speed of motion.

• Dynamic factor characterizes vehicle potential that can be created by powertrain. • Approach adds the conjoint effect of the engine, transmission, and driveline. • Includes power distribution among the wheels caused by driveline configuration. • Design factors assess effects on vehicle performance and power utilization. Vehicle terrain mobility characteristics, provided by the powertrain and running gear, are realized in dynamic interactions between the wheels and terrain. Approaches to modeling and simulation of vehicle-terrain interaction and mobility characteristics as well as engineering approaches to design powertrain sub-systems together pre-determine a vehicle's technical success or failure before it touches the ground. This article develops a vehicle mobility design technique, applicable to both manned and unmanned platforms, concerned with powertrain power conversion and realization in tire-terrain interactions. The modeling component is based on multi-drive-wheel vehicle longitudinal dynamics combined with terramechanics and powertrain characteristics. The approach advances the conventional dynamic factor by introducing the conjoint effect of the engine, transmission, and driveline system on vehicle traction and acceleration performance in terrain conditions where circumferential wheel forces and tire slippages may differ from each other. The vehicle design component of the proposed technique introduces drivetrain, driveline, and powertrain design factors that assess the influence of the drivetrain and driveline systems on traction, acceleration performance, power conversion, and realization at the wheels. The vehicle-design-for-mobility technique is completed by examining indices of mobility margins and performance. An analysis of several 8x8 armored personal carriers and 4x4 off-road vehicles illustrates the proposed technique. [ABSTRACT FROM AUTHOR]

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In this study, dynamic response analysis of functionally graded gears (FGGs) has been performed using a 6-degree of freedom dynamic model. The pinion and gear are divided into homogeneous sub-domains of uniform thickness, conforming to the gear tooth profile. The material composition varies radially according to power-law gradation with metal at the innermost and ceramic at the outermost surface. Mesh stiffness and transmission error of FGGs have been evaluated using a finite-element-based numerical method employing contact analysis. Results show that for considered values of gradient index (GI), FGGs show a 10% to 50% reduction in mesh stiffness with a 30% to 60% reduction in weight compared to steel gears of exact specifications. Also, FGGs show a 4% to 12% reduction in dynamic factor and a 9% to 17% reduction in peak-to-peak displacement amplitude than steel gears over the selected values of GI. [ABSTRACT FROM AUTHOR]

A brief analysis of different regulations for determining seismic loads based on the spectral theory shows that they have much in common but, at the same time, contain numerous amendments and clarifications for assessing true seismic effects. The calculation of seismic loads for one and the same conditions according to the regulations used in different countries produces significantly different results. According to the authors, there is a real possibility of creating common international regulations by refining and supplementing the existing ones. Apparently, the most promising regulations are European Standards EN 1998-2004/2012. The principle of calculation according to EN is more natural because seismic actions are actually transmitted to structures through a foundation. In addition, this approach allows consideration of a number of factors that affect the degree of seismic effects (ultimate shear resistance of soils, pressure on foundation soils, foundation−soil contact area, seismic beam tilt, etc.). An attempt is also made to assess the factors that impede the acceleration of building foundations during strong earthquakes. [ABSTRACT FROM AUTHOR]

In-service Portland cement concrete (PCC) pavements are subject to repeated dynamic loads from moving vehicles; thus, the actual stress generated in a PCC pavement may significantly differ from the static stress, which is normally used in the design and evaluation of pavement performance. Calculating the stress in PCC pavements under moving vehicle loads is of importance to assess their actual service condition, particularly for pavements with different surface roughness levels as the deteriorated roughness might cause large stress in PCC pavement subject to dynamic loads. In this paper, a method is proposed to compute the dynamic response in terms of loads and stresses generated in jointed plain concrete pavements (JPCPs) under a moving axle load, considering the effects of the pavement surface roughness, the vehicle parameters (including vehicle speeds and axle weights), and the pavement structure parameters (including thickness and elastic modulus of different layers and the existence of dowel bars). The dynamic axle load is firstly generated based on the quarter-car model, running through three successive slabs of which the surface roughness is determined by the power spectral density method, and the critical locations in slabs where the largest tensile stresses occur are identified. The combined effects of various pavement surface roughness levels, vehicle speeds, axle weights, and pavement structure parameters are evaluated in terms of the stress and the dynamic factor defined as the ratio of the tensile stress under dynamic load to the tensile stress under static load. For the roughness level D, the tensile stress can reach a maximum value of 3.13 MPa, and the dynamic factor can reach a maximum value of 2.46, which is much larger than the dynamic factor of 1.15 or 1.2 currently used in design guidebooks. Increasing the thicknesses of pavement slab or the subbase layer is an effective way to reduce the tensile stress in JPCP, while increasing the thickness of base layer is not effective. The results of this study can benefit future pavement design and pavement performance evaluation by providing the actual stress and the useful dynamic factor values for various conditions of field pavements. Moreover, preventive maintenance, particularly the improvement of pavement surface roughness, can be planned by referring to the results of this study, to avoid large tensile stress generated in JPCPs.

In view of the shortcomings of flower pollination algorithm, such as slow convergence speed, being easy to fall into local optimum and low convergence accuracy, an improved flower pollination algorithm based on triple dynamic adjustment was proposed. Firstly, the dynamic conversion probability was used to switch the search mode of the algorithm. Secondly, a new dynamic factor was introduced into the global search and update mechanism, and the sine and cosine step factor was introduced into the local development and update mechanism. Through the simulation experiments of seven test functions and compared with FPA, CS and ASCSA, the results show that the improved flower pollination algorithm has stronger global search ability and the ability to jump out of local optimum.

Introduction: Global spinal balance and its relationship to the pelvis have received much attention, and various formulae have been used to predict postoperative spinopelvic alignment for spinal surgery. However, previous studies had limitations because no consideration was given to the dynamic factor. Methods: Fifteen healthy adults without any lumbar disorder (group A) and 9 L4-spondylolisthesis patients (Group B) volunteered to participate in the study. Sequential images were captured with the subjects in the standing position with maximal forward bending followed by backward bending using a dynamic flat panel detector system. Spinopelvic parameters (LL: lumbar lordosis, SA: sacrofemoral angle, SS: sacral slope, PI: pelvic incidence, DP: distance of the horizontal movement of the pelvis) were evaluated. We also investigated the relationship between LL and SA (lumbar/hip [L/H] ratio) as the spinopelvic rhythm. Results: In group A, the mean change in LL was 83.2 ± 9.5°; change in SA, 45.4 ± 16.6°; SS, 42.6 ± 8.9°; PI, 43.2 ± 7.7°; DP, 15.7 ± 3.4 cm, and L/H ratio, 3.6 ± 2.7. However, spinopelvic rhythm changed over time, because the change in LL was larger than the change in SA from the middle of the rising motion to the upright position. In group B, the mean change in LL was 50.3 ± 8.0°; SA, 56.9 ± 16.0°; SS, 27.5 ± 13.5°; PI, 47.4 ± 10.4°; DP, 12.7 ± 6.8 cm; and L/H ratio, 1.0 ± 0.5. Conclusions: When compared with the change in LL, individual differences were largely noted in the change in SA. These results demonstrated that the range of hip joint motion under physiological conditions, unlike anatomical motion, differed substantially between individuals. Therefore, spinopelvic rhythm is dependent on the change in SA.

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Forestation as part of the Returning Farmland to Forest Project was implemented to mitigate soil erosion in southwestern China. However, whether forestation has effectively reduced soil erosion in southwestern China remains unclear, mostly because of the lack of monitoring forest cover change and soil erosion at watershed scales. We interpreted forest cover change from satellite images and simulated soil erosion changes for the period of 1986–2018 in the Chong'an River Basin with the Water and Tillage Erosion Model and Sediment Delivery Model. Our results show that the change in forest cover has the highest correlation coefficient with the sediment yield in the watershed, with an obvious inverse phase relationship between them for all the simulated years. From 2002 to 2014, large-scale forestation and frequent droughts caused the forest cover to vary, resulting in significant changes in the annual soil erosion amount. Because crevices favoring tree growth are more developed in limestone than in dolomite, the forest cover reduction on dolomite is significantly higher than that on limestone under severe droughts in karst areas. Our study implied that the function of forestation in preventing soil erosion depends on lithology in karst areas. [ABSTRACT FROM AUTHOR]

Copyright of Scientific Bulletin of National Mining University is the property of National Mining University, State Higher Educational Institution and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Brazilian Journal of Applied Economics / Economía Aplicada is the property of FEA-RP, Universidade de Sao Paulo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: The present study is an extension and update of Olver, Nicholaichuk, Kingston, and Wong's (2014) prospective multisite examination of sexual violence risk and treatment change on a large federal Canadian sample of 570 treated sexual offenders rated pretreatment and posttreatment on the Violence Risk Scale-Sexual Offense version (VRS-SO). Method: The present study featured the clinical application of a risk assessment and treatment planning tool, the VRS-SO, with recidivism outcome data updated by 4 years to a total of 10.2 years. VRS-SO change scores, representing reductions in sexual violence risk from treatment or other change agents (e.g., aging), were reanalyzed in terms of their associations with community sexual, violent, and general recidivism postrelease. Results: Recidivism base rates increased with the concordant increase in follow-up time. VRS-SO risk scores significantly predicted all recidivism outcomes, whereas change scores were consistently associated with decreases in sexual and violent recidivism after controlling for baseline risk through bivariate (d = −.24 to −.61) and Cox regression survival analyses (eB =.878 to.938). Conclusions: The results affirm the dynamic nature of sexual violence risk and demonstrate that structured assessments of change, linked to participation in sexual offense specific treatment, to be associated with decreases in future sexual offending as well as other recidivism outcomes. What is the public health significance of this article?: The research demonstrates that structured assessments of change in sexual violence risk, completed by sexual offender treatment service providers in the field using a validated sexual offense risk assessment tool, are associated with reductions in sexual offense recidivism as well as other forms of recidivism. The results further underscore the importance of long-term follow-up and comprehensive recidivism data to maximize the accuracy and forensic clinical utility of prediction findings. [ABSTRACT FROM AUTHOR]

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When the high-speed railway traffic is being organized, it becomes necessary to elaborate bridge design standards for high-speed railways (HSR). Methodology of studying the issues of HSR bridge design is based on the comprehensive analysis of domestic research as well as international experience in design, construction and operation of high-speed railways. Serious requirements are imposed on the HSR artificial structures, which raise a number of scientific tasks associated mainly with the issues of the dynamic interaction of the rolling stock and the bridge elements. To ensure safety of traffic and reliability of bridges during the whole period of operation one needs to resolve the dynamic problems of various types of high-speed trains moving along the structures. The article analyses dependences of the magnitude of inertial response on the external stress parameters and proposes a simplified method of determination of the dynamic live load factor caused by the passage of high-speed trains. The usefulness of the given research arises from the reduction of complexity of the complicated dynamic calculations needed to describe a high-speed train travelling along the artificial structures.

Common crossing rails are subjected to a rapid deterioration of the rolling surface due to a dynamic loading of trains. The present study is devoted to an experimental study of the displacement and rail strain measurements in the common crossing. The experimental measurements were carried out for two stiff common crossings under the dynamic loading of high-speed train for the velocity range of 54- 254 km/h. The results showed 2.5 times increase of the maximal displacements within the velocity range. The absence of the difference in the displacements between the trailing and the facing travel direction is explained with the relative displacement measurements between the rail and the sleeper and the different dynamic impact loading for the wing rail. The proposed model-based analysis of the absolute measurement of rail strain enables us to estimate the dynamic factor under the impact loading. The wing rail for trailing direction is almost twice as highly loaded as the frog rail for the facing direction. The maximal dynamic factor for the trailing direction shows almost no change for the velocities of more than 200 km/h. [ABSTRACT FROM AUTHOR]

Asymmetric spur gears are finding application in many fields including aerospace propulsion and automobile which demand unidirectional or relatively higher load on one side of the gear flank. Design intend to maximise the load carrying capacity of the drive side of asymmetric gear by increasing the pressure angle is achieved at the expense of coast side capacity. Multiple solution for coast to drive side pressure angle exist for a given contact ratio and each of these have relative merits and demerits. In the present work asymmetric spur gears of theoretically equal contact ratio as that of corresponding symmetric gears are selected to investigate the change in gear tooth static transmission error and dynamic behaviour with coast and drive side pressure angle. Study shows that dynamic factor of normal contact ratio asymmetric spur gears below resonance speed are relatively lower than corresponding symmetric gears of same module, contact ratio, number of teeth, coast side pressure angle and fillet radii. Results also show that, coast and drive side pressure angle can be suitably selected for a given contact ratio to reduce the single tooth and double tooth contact static transmission error and dynamic factor of asymmetric spur gears. [ABSTRACT FROM AUTHOR]

Modern regulations concerning railway bridges are based on the approach of structural dynamics, which is described in PN-EN standards. This paper presents the results of theoretical dynamic analysis of the HSLM-A train set loading on the structure of a pre-stressed concrete arch bridge - the first railway bridge of its type which was built in Poland (completed in 1959). The recommendations of PN-EN have been followed and modal analysis was carried out to define the sensitivity of the structure to chosen eigenforms. Additionally the paper presents a course of calculations and the conclusions obtained from the analysis of displacements, accelerations, and bending moments induced in the structure through a simulated passage of a high-speed train in the context of the requirements of PN-EN Standards. The conclusions from the current calculations can be used for dynamic analysis of bridges of similar structural solutions.

The paper presents selected aspects of dynamic numerical simulations of an orthotropic steel railway bridge loaded by high-speed trains. The model of moving loads was adopted in accordance with the models set out in the applicable standards. The current European code requirements are referred in which the computer calculations of the dynamic response of the structure are the basis for assessing the suitability of the structure to carry high-speed rail traffic (v > 160 km/h). In this research the calculations are based on the author’s method of generating traffic loads in Abaqus FEM environment. It is emphasized in the paper that in most commercial FEM codes (including Abaqus), moving loads are not implemented in modules responsible for defining of loads. The author’s approach to this issue allowed to obtain results confirming its adequacy. In the longer term, the authors will develop a plan to adapt this algorithm in order to generate traffic loads on bridges discretized as spatial and plane numerical models.

The simplified model of numerical analyses of discrete dislocation motion and emission from a stressed source was applied to predict the yield stress, dislocation creep, and fatigue crack growth rate of metals dominated by dislocation motion. The results obtained by these numerical analyses enabled us to link various dynamical effects on the yield stress, dislocation creep, and fatigue crack growth rate with the experimental results of macroscopic phenomena, as well as to link them with theoretical results obtained by the concept of static, continuously distributed infinitesimal dislocations for the equilibrium state under low strain or stress rate conditions. This will be useful to holistic research approaches with concern for time and space scales, that is, in a time scale ranging from results under high strain rate condition to those under static or low strain rate condition, and in a space scale ranging from meso-scale to macro-scale mechanics. The originality of results obtained by these analyses were found by deriving the analytical formulations of number of dislocation emitted from a stressed source and a local dynamic stress intensity factor at the pile-up site of dislocations as a function of applied stress or stress rate and temperature material constants. This enabled us to develop the predictive law of yield stress, creep deformation rate, and fatigue crack growth rate of metals dominated by dislocation motion. Especially, yielding phenomena such as the stress rate and grain size dependence of yield stress and the delayed time of yielding were clarified as a holistic phenomenon composed of sequential processes of dislocation release from a solute atom, dislocation group moving, and stress concentration by pile-up at the grain boundary.

The article considers the organizational and methodological approaches for realization of the analysis of condition, movement and dynamics of fixed assets on the example of meat-processing enterprises. Various approaches to characteristics of fixed assets, ranging from Adam Smith to modern authors, have been considered. Most authors associate fixed assets with capital assets, as well as fixed assets with capital funds. As a result of the generalization of different points of view, we have proposed the following definition of fixed assets. For the realization of the analysis of the movement and updating of fixed assets, tasks and ways of organizing the analysis have been defined as well as indicators with the help of which the results of the movement and updating of fixed assets will be determined. Based on general methods, the analysis of the movement of fixed assets was carried out using the index of input, retirement and updating. The results of the analysis showed that enterprises have a very low index of retirement, which negatively affects the results of the updating of fixed assets and indicates an irrational use of fixed assets. Analysis of suitability and depreciation of fixed assets was proposed to carry out taking into specific gravity the percentage of the active part of fixed assets. As a result of the analysis that was carried out, it was found that the index of suitability at the enterprises is less than fifty percent. It was also found that the useful life significantly exceeds the standard, which is recommended in the Tax Code of Ukraine. During the analysis, it was established that the index of real value of fixed assets, both by their full cost and by their active part, is in the critical interval. This fact lengthens the use of obsolete fixed assets and makes it impossible to implement an intensive and innovative policy of the development of meat processing enterprises. [ABSTRACT FROM AUTHOR]