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Vertical electrical sounding (VES) and Rayleigh wave exploration are widely used in the exploration of near-surface structure, but both have limitations. This study aims to make full use of the advantages of the two methods, reduce the multiple solutions of single inversion and improve the accuracy of the inversion. Thus, a nonlinear joint inversion method of VES and Rayleigh wave exploration based on improved differential evolution (DE) algorithm was proposed.

Based on the DE algorithm, a new initialization strategy was proposed. Then, taking AK-type with high-velocity interlayer model and HA-type with low-velocity interlayer model near the surface as examples, the inversion results of different methods were compared and analyzed. Then, the proposed method was applied to the field data in Chengde, Hebei Province, China. The stratum structure was accurately depicted and verified by drilling.

The synthetic data and field data results showed that the joint inversion of VES and Rayleigh wave data based on the improved DE algorithm can effectively improve the interpretation accuracy of the single-method inversion and had strong stability and large generalizable ability in near-surface engineering problems.

A joint inversion method of VES and Rayleigh wave data based on improved DE algorithm is proposed, which can improve the accuracy of single-method inversion.

In the current study, corporate investment is examined by using a user cost of capital model for two important Latin American economies: Brazil and Mexico. In this paper, a dynamic user cost of capital model is employed. The extended model also accounts the investment model with the convex adjustment cost. Moreover, the link between structural change, financial liberalization and investment is also investigated. The present study, therefore, sheds new lights on the investment behavior of the Latin American emerging markets.

The differenced generalized method of moments approach is employed to control the endogeneity, heteroscedasticity and autocorrelation for modeling the corporate investment over 20 years for both countries.

The findings indicate that the dynamic user cost of capital-based investment model explains the corporate investment in Brazil and Mexico. Especially, the interest rate and depreciation explain the investment behavior of nonfinancial firms in both countries. At the same time, structural change and financial liberalization do not have a significant impact on interest rates, an important user cost of capital.

This is the first study examines the corporate investment using dynamic user costs of capital approach for an emerging market. The user cost of capital-based investment models is clearly understudied models for emerging markets. This study is particularly important for emerging markets as investment models need to have a theoretical background.

En el presente estudio se examina la inversión empresarial utilizando un modelo de coste de capital del usuario para dos importantes economías latinoamericanas: Brasil y México. En este trabajo se emplea un modelo dinámico de coste de capital para el usuario. El modelo ampliado también tiene en cuenta el modelo de inversión con el coste de ajuste convexo. Además, se investiga la relación entre el cambio estructural, la liberalización financiera y la inversión. El presente estudio, por tanto, arroja nueva luz sobre el comportamiento de la inversión en los mercados emergentes latinoamericanos.

Se emplea el método GMM diferenciado para controlar la endogeneidad, la heteroscedasticidad y la autocorrelación en la modelización de la inversión empresarial a lo largo de 20 años en ambos países.

Los resultados indican que el modelo dinámico de inversión basado en el coste de capital para el usuario explica la inversión empresarial en Brasil y México. Especialmente, el tipo de interés y la depreciación explican el comportamiento de la inversión de las empresas no financieras en ambos países. Al mismo tiempo, se constata que el cambio estructural y la liberalización financiera no tienen un efecto significativo sobre los tipos de interés, que es un importante coste de uso del capital.

Este es el primer estudio que examina la inversión empresarial utilizando un enfoque dinámico basado en los costes de capital para un mercado emergente. Los modelos de inversión basados en los costes de uso del capital son claramente modelos poco estudiados para los mercados emergentes. Este estudio es especialmente importante para los mercados emergentes, ya que los modelos de inversión deben tener un trasfondo teórico.

In the current manuscript, the authors examine the Belleville spring with the variable thickness. The thickness is assumed to be variable along the meridional and parallel coordinates of conical coordinate system. The calculation of the Belleville springs includes the cases of the free gliding edges and the edges on cylindric curbs, which constrain the radial movement. The equations developed here are based on common assumptions and are simple enough to be applied to the industrial calculations.

In the current manuscript, the authors examine the Belleville spring with the variable thickness. The calculation of the Belleville springs investigates the free gliding edges and the edges on cylindric curbs with the constrained radial movement. The equations developed here are based on common assumptions and are simple enough to be applied to the industrial calculations.

The developed equations demonstrate that the shift of the inversion point to the inside edge does not influence the bending of the cone. On the contrary, the character of the extensional deformation (circumferential strain) of the middle surface alternates significantly. The extension of the middle surface of free gliding spring occurs outside the inversion. The middle surface of the free gliding spring squeezes inside the inversion point. Contrarily, the complete middle surface of the disk spring on the cylindric curb extends. This behavior influences considerably the function of the spring.

A slotted disk spring consists of two segments: a disk segment and a number of lever arm segments. Currently, the calculation of slotted disk spring is based on the SAE formula (SAE, 1996). This formula is limited to a straight slotted disk spring with freely gliding inner and outer edges.

The equations developed here are based on common assumptions and are simple enough to be applied to the industrial calculations. The developed method is applicable for disk springs with radially constrained edges. The vertical displacements of a disk spring result from an axial load uniformly distributed on inner and outer edges. The method could be directly applied for calculation of slotted disk springs.

The nonlinear governing equations for the of Belleville spring centres were derived. The equations describe the deformation and stresses of thin and moderately thick washers. The variation method is applicable for the disc springs with free gliding and rigidly constrained edges. The developed method is applicable for Belleville spring with radially constrained edges. The vertical displacements of a disc spring result from an axial load uniformly distributed on inner and outer edges.

This study aims to examine the performance of environmental, social and governance (ESG) equity indices in Latin America (LA), evaluating their risk-return characteristics in comparison to conventional benchmark indices.

Using a quantitative empirical approach, the authors analyze ESG equity indices from Brazil, Mexico, Chile, Peru and Colombia, employing metrics such as Sharpe, Sortino and Omega ratios to measure risk-adjusted returns. Regression analysis is employed to assess the replicability of ESG indices by benchmark indices. Monte Carlo simulations are conducted to explore the potential increase in risk-adjusted returns when ESG equity indices are incorporated into portfolios.

The study addresses critical questions for investors: Can ESG indices outperform their benchmarks? Can these ESG indices be replicated by benchmark counterparts? Do ESG equity indices enhance portfolio diversification? The findings reveal that investing in ESG indices has the potential to enhance risk-adjusted returns and portfolio diversification.

While this study focuses on various LA economies, it’s important to note variations in currency and volatility.

For investors in LA, this study highlights the importance of considering ESG indices as part of their investment strategies. While not all ESG indices outperform conventional ones, some may improve diversification and risk-adjusted performance. Investors should carefully assess market-specific conditions and national factors when making investment decisions.

The primary contribution of this study is its focus on LA countries in the examination of diverse portfolios. The research provides valuable insights into the performance of ESG indices in this region compared to conventional benchmark indices. This approach addresses an important gap in the existing literature and offers a more comprehensive perspective on ESG investing and portfolio diversification.

Se examina el rendimiento de los índices-ESG en América Latina (AL), evaluando sus características de riesgo y retorno en comparación con los índices convencionales.

Utilizando un enfoque cuantitativo, analizamos los índices-ESG de Brasil, México, Chile, Perú y Colombia, empleando ratios de Sharpe, Sortino y Omega para medir los rendimientos ajustados al riesgo. Se utiliza análisis de regresión para evaluar la replicabilidad de los índices-ESG por parte de los índices de referencia. Se realizan simulaciones de Monte-Carlo para explorar el aumento en los rendimientos ajustados al riesgo cuando se incorporan los índices-ESG en las carteras.

El estudio aborda preguntas críticas: ¿Pueden los índices-ESG superar a sus índices de referencia? ¿Pueden estos índices-ESG ser replicados por sus contrapartes de referencia? ¿Mejoran los índices-ESG la diversificación de las carteras? Los hallazgos revelan que la inversión en índices-ESG tiene el potential de mejorar los rendimientos y la diversificación de las carteras de inversión.

Aunque este estudio se centra en diversas economías de AL, es importante tener en cuenta variaciones en moneda y volatilidad.

La principal contribución de este estudio radica en su enfoque en países de AL en el examen de carteras diversas; ofrece valiosos conocimientos sobre el rendimiento de los índices-ESG en esta región en comparación con los índices convencionales.

The purpose of this paper is using a model-free reinforcement learning (RL) algorithm to optimize manipulability which can overcome difficulties of dilemmas of matrix inversion, complicated formula transformation and expensive calculation time.

Manipulability optimization is an effective way to solve the singularity problem arising in manipulator control. Some control schemes are proposed to optimize the manipulability during trajectory tracking, but they involve the dilemmas of matrix inversion, complicated formula transformation and expensive calculation time.

The redundant manipulator trained by RL can adjust its configuration in real-time to optimize the manipulability in an inverse-free manner while tracking the desired trajectory. Computer simulations and physics experiments demonstrate that compared with the existing methods, the average manipulability is increased by 58.9%, and the calculation time is reduced to 17.9%. Therefore, the proposed method effectively optimizes the manipulability, and the calculation time is significantly shortened.

To the best of the authors’ knowledge, this is the first method to optimize manipulability using RL during trajectory tracking. The authors compare their approach to existing singularity avoidance and manipulability maximization techniques, and prove that their method has better optimization effects and less computing time.

In this paper, the authors study the nonlinear matrix equation Xp=Q±A(X-1+B)-1AT, that occurs in many applications such as in filtering, network systems, optimal control and control theory.

The authors present some theoretical results for the existence of the solution of this nonlinear matrix equation. Then the authors propose two iterative schemes without inversion to find the solution to the nonlinear matrix equation based on Newton's method and fixed-point iteration. Also the authors show that the proposed iterative schemes converge to the solution of the nonlinear matrix equation, under situations.

The efficiency indices of the proposed schemes are presented, and since the initial guesses of the proposed iterative schemes have a high cost, the authors reduce their cost by changing them. Therefore, compared to the previous scheme, the proposed schemes have superior efficiency indices.

Finally, the accuracy and effectiveness of the proposed schemes in comparison to an existing scheme are demonstrated by various numerical examples. Moreover, as an application, by using the proposed schemes, the authors can get the optimal controller state feedback of $x(t+1) = A x(t) + C v(t)$.

This paper aims to propose a bidirectional hidden converter (BHC)-based three-phase DC–AC conversion for energy storage application. BHC is the new concept to vary an energy storage device voltage into wide range. Hidden converter power loss and power rating are reduced by using zero-sequence injection-based carrier-based pulse-width modulation (CBPWM) strategy.

By using this control strategy, a BHC processes only little amount of power during double-stage conversion, mostly during direct or single-stage conversion of the three-phase three-port converter (TPTPC) only processing the maximum power.

TPTPC consists of two sets of positive group switches for inversion process, one set of switches is regular inverter switches called vertical positive group switches, and the second set is anti-series switches, which are horizontally connected for direct or single-stage conversion.

Characteristics, principles and implementations of proposed DC–AC 3Ø conversion system and its PWM strategy are analyzed. Through experimental outputs, the effectiveness and viability of the proposed solutions are validated.

A low-level controller is critical to the overall performance of multirotor unmanned aerial vehicles. The purpose of this paper is to propose a nonlinear low-level angular velocity controller for multirotor unmanned aerial vehicles in various operating conditions (e.g. different speed and different mode).

To tackle the above challenge, the authors have designed a nonlinear low-level controller taking the actuator dynamics into account. The authors first build the actuator subsystem by combining the actuator dynamics with the angular velocity dynamics model. Then, a recursive low-level controller is developed by designing a high-gain observer to estimate unmeasurable states. Furthermore, a detailed stability analysis is given with the Lyapunov theory.

Simulation tests and real-world flying experiments are provided to validate the proposed approach. In particular, we illustrate the performance of the proposed controller using violent random command test, attitude mode flight and high-speed flight of up to 18.7 m/s in real world. Compared with the classical method used in PX4 autopilot and the estimation-based incremental nonlinear dynamic inversion method, experimental results show that the proposed method can further reduce the control error.

Low-level control of multirotor UAVs is challenging due to the complex dynamic characteristics of UAVs and the diversity of tasks. Although some progress has been made, the performance of existing methods will deteriorate as operating conditions change due to the disregard for the electromechanical characteristics of the actuator.

To solve the low-level angular velocity control problem in various operating conditions of multirotor UAVs, this paper proposes a nonlinear low-level angular velocity controller which takes the actuator dynamics into account.

The paper aims to understand the role of sensory quality scoring used at the competition auctions on pricing outcomes and how the auction process could be improved to increase sustainability in the specialty coffee market.

The authors build a conceptual model explaining the potential role of sensory quality scoring in generating inequitable outcomes in specialty coffee auctions. The authors' research is exploratory. The authors base the propositions on the findings of the extant literature and our analysis of data from 24 Best of Panama (BOP) Auctions that took place between 2017 and 2021.

A striking feature in recent BOP Auctions is a winner-takes-all (WTA) outcome. The authors also document the presence of significant price inversion. The authors attribute these outcomes to the interactions of information-poor producers, information-rich intermediaries and conspicuous consumers in competition auctions, where the product quality measurement is highly unreliable.

Data need to be gathered more broadly to enable the operationalization of the current propositions into testable hypotheses.

These strategies intend to provide guidelines for producers, consumers and other value chain participants on creating equitable solutions to a thriving industry where a WTA phenomenon occurs.

The current study is the first to argue that existing quality scoring practices, as well as conspicuous consumption, contribute to the inequities. Finally, the study proposes novel interventions to standardize the quality grading protocols and communicate them transparently to both producers and consumers.

The purpose of this chapter is to characterize fictitious capital and fictitious profits as extreme expressions of the fetishism of capital. Considering the incessant search for valorization and allowing for fictitious forms of capital, the subject of this study is at the center of the dynamics of recent capitalist accumulation, especially when we take into account the capitalist crises over the last four or five decades. Its mechanism of fictitious valorization (M – M′), a decisive dimension of contemporary capitalism, is contradictory, based on the growing obstacles to the extraction of surplus value on an expanded scale, and therefore the real valorization of capital. At the same time, we support the idea that this mass of overaccumulated capital produces profits unrelated to surplus value, that is fictitious profits, further intensifying the fetishistic and contradictory nature of capitalism.