Inverse Integration Research Articles

Bridge Profile and Vehicle Property Determination Using Vehicle Fleet Monitoring Concept

Over the past 20 years, drive-by monitoring, using data from sensors in passing vehicles, has become increasingly popular due to its low cost and high efficiency at a network level. Despite significant advances, the dynamics of vehicles remains one of the main challenges to overcome before accurately identifying critical information about the infrastructure being crossed, bridges or road pavements. This paper introduces a novel approach to estimating bridge profiles (i.e. road surface profiles on the bridges) and vehicle properties using a fleet of passing vehicles. In this method, bridge profiles are first calculated using the innovative Inverse Newmark-beta integration method, and the cross-entropy optimization algorithm is employed to solve the problem. Numerical results demonstrate that the proposed approach is highly effective in extracting bridge profiles and predicting vehicle properties, even in scenarios with significant levels of measurement noise.

Analysis of fractional Euler-Bernoulli bending beams using Green’s function method

This paper deals with the effect of fractional order on the fractional Euler-Bernoulli beams model. This model is based on the elastic curve that can be approximated using tangent lines and the osculating circle. We introduce a general form of the fractional Green’s function for the highest-order term 1<α≤2, which gives a unique solution for the geometrical fractional bending beams with an inhomogeneous fractional differential equation. The analytical closed-form responses were obtained by inverse problem technique and integration over Green’s function kernel. The theory and properties of fractional Green’s function method are described by generalizing classical theory to the initial and two-point fractional boundary value problems. Static analysis of the numerical examples, such as determinate and indeterminate beams with typical loads and beam property boundary conditions, are presented and discussed. The results were verified using the direct integration method. The fractional conventional ratio indicates the beam's deformation deviation from its classical state. The analysis results reveal that changing the fractional parameter significantly impacts the deflection behavior of flexural beams due to the beam’s characteristics and the fractional order. The behavior of the fractional beam is identical to the classical state when the fractional parameter is an integer number.

Lithium battery health state assessment based on vehicle-to-grid (V2G) real-world data and natural gradient boosting model

Accurate state of health (SOH) estimation of batteries in vehicle-to-grid (V2G) applications is critical for the safety of vehicles, chargers, and grids. In this paper, a novel SOH estimation model based on inverse ampere-time integration and natural gradient boosting (NGBoost) is proposed and verified by real operating data from V2G electric vehicles (EVs). Raw data is segmented, where segments of charging and grid-feeding with relatively smooth currents are selected to constitute the dataset for research. On top of this, five model inputs have been selected through Pearson correlation and physical meaning analysis. Hyperparameters of the model are optimized and model performance is compared with the other nine commonly used machine learning methods. The results show that the NGBoost model has the highest estimation accuracy with the mean absolute percentage error and root mean squared error of 1.484% and 2.302 A h, respectively. To increase the transparency of the model, the Shapley additive explanation (SHAP) method is utilized to provide a full explanation of its predictions. Furthermore, the model is validated to be robust to noise and shows great potential for integration into embedded battery management systems for fast and accurate SOH estimation in V2G applications.

Summary and overview of the first ISMRM workshop onmagnetic resonance elastography, August 25-26, 2022, Berlin, Germany.

An ISMRM workshop on MR elastography was held at Charité-Universitätsmedizin Berlin on August 25-26, 2022. As an exclusively in-person event, 65 participants from 9 countries attended the workshop despite COVID-19-related restrictions. The topics of the workshop covered cellular and microtissue mechanical interactions, the development of MR elastography driver technology, approaches to inverse problems, clinical applications, and integration of MR elastography into multiparametric MRI protocols. The workshop was a great success by promoting direct knowledge exchange as well as for strategizing future directions for MR elastography. In this symposium review, we briefly summarized all oral presentations as well as the concluding panel discussion.

Design and Implementation of Simplified Symmetry Chaotic Circuit

In order to reduce the circuit cost and improve the stability and flexibility of the circuit, a simplified symmetry chaotic circuit was designed and implemented by using an inverse integration circuit and a voltage follower as isolators. The change of different symmetry chaotic dynamic behaviors caused by the change of parameters can be realized by adjusting the time constant. The behavior coexistence characteristics and amplitude control characteristics under different initial conditions were verified. The results of circuit experiments are in good agreement with those of numerical simulation and theoretical analysis. This method is effective and feasible.

Understanding the Regional Integration Process from the Perspective of Agglomeration and Urban Networks: Case Study in Central China.

Previously, urban planning approaches have tended to convert local agglomeration into network connections to advance urban development. However, is this successful experience learned from developed counties appropriate for developing countries? Scholars hold different opinions on this debate. To answer this question, we need to examine the effects of urban agglomeration in developing countries with a quantitative method. In this paper, we introduced a method of examining network connections from a geospatial perspective to explore the practice and spatial consequences of regional integration using a new concept of “coupling distance” based on metal valence bond theory. Then we applied this method to conduct an empirical case study of the urban agglomeration in the middle reaches of the Yangtze River region in China. We found that: (1) the real integration scale of the investigated urban areas was less than one-fourth the planned area, as most of interactions between cities are local, although we see the positive facilitation of urban networks on cross-provincial integration. (2) In terms of spatial consequences, the study area demonstrated phenomena of “agglomeration shadows”, “enclaves” and “inverse integration”. Specifically, these “agglomeration shadows” were all in their province’s geometric centers, which seemed to have suffered a “central position curse”. (3) Both “enclaves” and “inverse integration” call for a readjustment of government-led regional integration planning. Differently, the former has a positive attitude towards integration while the latter holds the opposite attitude. This study hopes to provide operationalizing methods and guidelines for planners and decision makers in the field of regional integration planning.

Railway Bridge Condition Monitoring Using Numerically Calculated Responses from Batches of Trains

This study introduces a novel method to determine apparent profile of the track and detect railway bridge condition using sensors on in-service trains. The concept uses a type of Inverse Newmark-β integration scheme on data from a batch of trains. In a self-calibration process, an optimization algorithm is used to find vehicle dynamic properties and speed. For bridge health monitoring, the apparent profile of the bridge is first determined, i.e., the true profile plus components of ballast and bridge deflection under the moving train. The apparent profile is used, in turn, to calculate the moving reference deflection influence line, i.e., the deflection due to a moving (static) unit load. The moving reference influence line is shown to be a good indicator of bridge stiffness. This numerical approach is assessed using an elaborate finite element model operated by an independent research group. The results show that the moving reference influence line can be found accurately and that it constitutes an effective indicator of the condition of a bridge.

A novel exponential‐type anti‐windup method applied to the power converter in marine electrical propeller system

This paper proposes a novel exponential anti-windup method for a high-proportional-load marine electrical propeller system, allowing the system to respond to changes in working conditions that would make the control system operate in the open-loop state and severely affect the system stability and dynamic response speed. First, the commonly used inverse calculation type and conditional integration type anti-windup methods are discussed, and the two methods are compared and analysed. The proposed exponential anti-integral saturation method is obtained by introducing an exponential link in the PI controller to weaken the effect of the integral link when the controller output is saturated to improve the control performance of the traditional anti-integral saturation method when the operating conditions of the marine electrical propeller system change. To verify the accuracy of the theoretical analysis, experiments were conducted using starsim. The experimental results verify that the theoretical analysis and parameter design are correct and superior and have the characteristics of fast desaturation and small overshoot of the system. The method has good theoretical research significance and practical application prospects for improving the comprehensive performance of marine electrical propeller systems.

Mathematical tricks for pseudopotentials in the theories of nonlinear waves in plasmas

In the analysis of nonlinear waves in plasma, especially for the search for periodic waves, shock waves, and solitons, mechanical analogy methods are widely applicable. The most famous of them is the Sagdeev pseudopotential method. However, sometimes mathematical difficulties arise when deriving formulas for pseudopotentials. The author proposes three mathematical tricks to get around these difficulties and obtain exact formulas for pseudopotentials in cases where the direct, Sagdeev method is considered inapplicable: a trick based on the Lambert W-function, a trick based on the inverse function integration, and a trick based on reducing the theory equations to the Bernoulli differential equation (the Bernoulli pseudopotential method). This article, which is methodological by nature, provides detailed examples of the application of each of these tricks when deriving formulas for pseudopotentials.

Light Recycling Using Perovskite Solar Cells in a Half‐Cylinder Photonic Plate for an Energy Efficient Broadband Polarized Light Emission

Energy efficiency in many illumination devices is far from optimal. For instance, in liquid crystal displays, a large fraction of the emitted light is lost provided absorbing polarizers are used for the image formation. Herein, a light‐guiding structure to achieve diffuse polarized light emission from the top of the guide, combined with light harvesting and conversion back into electricity of the light with the unwanted polarization is proposed. Key in achieving such a double goal is the use of a half‐cylinder photonic plate for an ergodic light‐guided propagation incorporating a nonabsorbing reflective multilayer light polarizer and perovskite (PVK) solar cells. In the complex combination of micro‐ and nanometric dimensions of the proposed structure, light propagation was resolved using ray optics tracing interlaced with a full wave vector inverse integration approach. A broadband polarization extinction ratio of 0.1 for the light diffused from the top surface is demonstrated, while close to 90% of the s‐polarized light remains trapped and can be recycled back to electricity by the PVK solar cells placed on the front and back ends of the guide. PVK cells are shown to be optimal in such conversion with an overall efficiency ranging from 38 to 52%.

Experimental investigation of the cryogenic [formula omitted]-cooling performance for an impinging jet configuration for different inflow conditions

This work focuses on the cryogenic impingement cooling performance depending on the given inflow conditions. An experimental setup is presented which allows a detailed observation of the time dependent temperature distribution in a solid body via a thermal imaging camera during the cooling process. The space- and time-dependent heat transport from the solid to the impinging fluid is calculated from the gained temperature data using the so-called inverse global integration method (IGIM). This method allows an accurate determination of the heat flux density without the necessity of a precise calculation of the sensible temperature gradients. An investigation of the LN2-impingement conditions such as mass flow rates and fluid density is conducted to bridge the gap between the inflow conditions and the resulting heat fluxes. Moreover, a variation of the working pressure and the nozzle geometry is also performed to assess the main dependencies of the cooling performance. Thus, some important conclusions regarding the heat flux and its governing physical phenomena can be drawn. In order to simplify the application of the gathered information, the corresponding heat transfer coefficients are calculated as a function of the time dependent surface temperature and the set inflow conditions. It is shown that the usage of a constant value results in a high inaccuracy because the heat flux density and the heat transfer coefficient show no trivial correlation for arbitrary impingement conditions.

Short-Term Retest Performance in Young versus Older Adults: Consideration of Integrated Speed-Accuracy Measures

ABSTRACT Objectives The current research addressed gaps in the literature regarding short-term computerized cognitive retest performance in young and older adults using two integrated speed-accuracy metrics. The aims were: (a) to advance the aging literature on short-term retest performance using a computerized cognitive battery and a retest schedule that included both within- and between-day time points, and (b) to assess the test-retest reliability of two integrated speed-accuracy metrics, inverse efficiency scores (IES) and balanced integration scores (BIS). Method Twenty young (18–23 years) and thirty older (65–71 years) men completed a battery measuring a range of cognitive functions, six times over three testing days, each 1 week apart. Result Compared to young adults, older adults exhibited steeper within- and between-day performance gains in IES and BIS, which may reflect a combination of lower initial cognitive ability and familiarity, indicating that older adults may require more familiarization on computerized tests. Relative to unadjusted reaction times, IES reliability appeared comparable in older adults, but slightly lower among young adults. The reliability of BIS was lower than unadjusted reaction times and IES in both age groups. Discussion Our findings provide guidance for researchers wanting to combine speed and accuracy into a single performance metric in repeated testing contexts.

Neuromorphic NEF-Based Inverse Kinematics and PID Control.

Neuromorphic implementation of robotic control has been shown to outperform conventional control paradigms in terms of robustness to perturbations and adaptation to varying conditions. Two main ingredients of robotics are inverse kinematic and Proportional–Integral–Derivative (PID) control. Inverse kinematics is used to compute an appropriate state in a robot's configuration space, given a target position in task space. PID control applies responsive correction signals to a robot's actuators, allowing it to reach its target accurately. The Neural Engineering Framework (NEF) offers a theoretical framework for a neuromorphic encoding of mathematical constructs with spiking neurons for the implementation of functional large-scale neural networks. In this work, we developed NEF-based neuromorphic algorithms for inverse kinematics and PID control, which we used to manipulate 6 degrees of freedom robotic arm. We used online learning for inverse kinematics and signal integration and differentiation for PID, offering high performing and energy-efficient neuromorphic control. Algorithms were evaluated in simulation as well as on Intel's Loihi neuromorphic hardware.

Non-linear dynamic analysis of reinforced concrete structures with hybrid mixed stress finite elements

This paper presents and discusses a hybrid-mixed stress (HMS) finite element model for the static and dynamic analysis of 2D reinforced concrete frame structures. It is assumed a physically non-linear behaviour for both concrete and steel. In this model, both the stress and the displacement fields are approximated in the domain of each element. Complete sets of orthonormal Legendre polynomials are used as approximation functions. The use of these functions makes possible the definition of analytical closed form solutions for the computation of all structural operators when a physically linear behaviour is assumed and leads to the development of very effective p- refinement procedures. Due to the nature of the HMS formulation, it is possible to consider the use of both inverse and direct integration schemes at the cross-section level. The time integration procedure uses classical step-by-step techniques, such as Newmark and α-HHT method. The latter is used in order to supress some numerical noise that may occur in the iterative procedure involved in the solution of dynamic non-linear problems. Three different types of damage models, with and without permanent strains, are used to model concrete behaviour. To validate the model, to illustrate its potential and to assess its accuracy and efficiency, several numerical examples are discussed, and comparisons are made with solutions provided by other numerical techniques.

Experimental determination of the cooling performance of liquid nitrogen for machining conditions

This paper presents an experimental investigation of cryogenic cooling with liquid nitrogen. A thermal imaging camera is used to measure the temperature distribution of a pre-heated titanium alloy (Ti-6Al-4V) specimen interacting with a flow of liquid nitrogen. The main objective of this work is to determine the surface heat transfer in a robust way. A new method, the so-called inverse global integration method (IGIM), is introduced which allows the calculation of the heat transfer from a solid body to the cryogenic medium using all available pixel points of a thermogram. Reproducible and accurate results could be achieved by ensuring well-defined initial and boundary conditions during the execution of the experiment. The parameters with the highest impact on the heat transfer are the surface temperature, nozzle distance, as well as the working pressure in the nitrogen tank. The work is completed by performing curve fitting on the experimental results in order to compare the cooling performance and to simplify the technical application.

Спеціалізований програмний калькулятор для обчислення значень функції Ламберта W0(X) і споріднених з нею функцій

Запропоновано спеціалізований програмний калькулятор, призначений для обчислення значень функції Ламберта W0(х) і споріднених з нею функцій. Описана його програмна реалізація і наведено приклади обчислень. Калькулятор надає обчислювати значення верхньої гілки функції Ламберта, величину обернену до величини функції Ламберта, логарифм функції Ламберта, експоненту, показник ступеня якої містить функції Ламберта, значення першої і другої похідних, значення узагальненого логарифма, узагальненого тангенса, узагальненого котангенса, узагальненого синуса, узагальненого косинуса, гіперболічний узагальнений тангенс, гіперболічний узагальнений котангенс, гіперболічний узагальнений синус, гіперболічний узагальнений косинус. Калькулятор дозволяє обчислювати значення двох найбільш поширених видів визначених інтегралів, підінтегральна функція яких містить функцію Ламберта. Проведено порівняння різних засобів обчислення значень функції Ламберта і рекомендовані області їх застосування.

Linear superposition of regular black hole solutions of Einstein nonlinear electrodynamics

In this paper we focus on certain properties of the Schwarzschild metrics that, to the best of our knowledge, have gone unnoticed. These properties include (i) the existence of a generalized Birkhoff theorem for general nonlinear electrodynamics, (ii) the existence of two double eigenvalues of the Einstein tensor ${{G}^{\ensuremath{\mu}}}_{\ensuremath{\nu}}$ coincident in number with the two pairs of eigenvalues of the electrodynamics energy-momentum tensors, (iii) the partial fitting of the dominant energy conditions, (iv) linear superpositions of solutions of the Einstein electrodynamics equations through the inverse integration method, and (v) the generating technique of solutions with a Reissner-Nordstr\om limit at spatial infinity. Each of these aspects are treated in detail, and a class of regular black hole solutions is reported and studied to some extent.

Las prácticas pedagógicas y la inclusión de los estudiantes con necesidades educativas especiales (NEE)

This article presents results from the research Analysis and Pedagogical Interventions: Identifying Successful Inclusive Pedagogical Practices, which aimed to characterize inclusive pedagogical practices in two classes of Inverse literacy integration, in schools of the public network of the Federal District and Brasilia-Brazil. The Methodology, with qualitative character, with participant observation, questionnaire, semi-structured interviews and analysis of documents and school records of students with Specific Educational Needs-NEEs involved. The results indicated the dynamic and flexible planning, the use of materials, diverse pedagogical strategies and evaluation, the organization of the physical space of the classroom for the collaborative work, as strategies that characterize the inclusive pedagogic practice and the need for greater investment in the training of teachers to respond to the diversity of learning styles of all students.

Investigation on mining subsidence over Appin–West Cliff Colliery using time-series SAR interferometry

ABSTRACTAdvanced Time Series InSAR (ATS-InSAR) generally refers to those TS-InSAR methods with an external distributed scatterer selection module, e.g. SqueeSAR™, and GEOS-ATSA (Advanced Time-Series Analysis). It is being known as a very efficient tool for monitoring ground deformation over suburban or non-urban regions with great success. However, research conducted using C-band Envisat-based ATS-InSAR failed to produce reasonable outcome within Appin Colliery primarily due to the underground mining effect, which is located in the southeastern corner of the Southern Coalfield, New South Wales, Australia; thus, the general underground mining pattern cannot be formed. This work presents a modified ATS-InSAR method for mapping the ground deformation over underground mining region. More specifically, in order to achieve the best outcome, a modified measurement scatterer (MS) pixel selection method is introduced by including less reliable MS pixels through an Inverse Distance Weighted-based integration method. In addition, the proposed method is also applied to C-band Sentinel-1 image stacks for testing purpose, and the final result proved to be efficient to offer sufficient information to the mining industry and government for risk management purpose.

Monolithic CIGS–Perovskite Tandem Cell for Optimal Light Harvesting without Current Matching

We present a novel monolithic architecture for optimal light harvesting in multijunction thin film solar cells. In the configuration we consider, formed by a perovskite (PVK) cell overlying a CIGS cell, the current extracted from the two different junctions is decoupled by the insertion of a dielectric nonperiodic photonic multilayer structure. This photonic multilayer is designed by an inverse integration approach to confine the incident sunlight above the PVK band gap in the PVK absorber layer, while increasing the transparency for sunlight below the PVK band gap for an efficient coupling into the CIGS bottom cell. To match the maximum power point voltages in a parallel connection of the PVK and CIGS cells, the latter is divided into two subcells by means of a standard three-laser scribing connection. Using realistic parameters for all the layers in the multijunction architecture we predict power conversion efficiencies of 28%. This represents an improvement of 24% and 26% over the best CIGS and PVK sin...