Wenjing Wu, Ning Zhao, Liang Zhang and Yuhang Wu
This paper aims to investigate the problem of adaptive bipartite tracking control in nonlinear networked multi-agent systems (MASs) under the influence of periodic disturbances…
Abstract
Purpose
This paper aims to investigate the problem of adaptive bipartite tracking control in nonlinear networked multi-agent systems (MASs) under the influence of periodic disturbances. It considers both cooperative and competitive relationships among agents within the MASs.
Design/methodology/approach
In response to the inherent limitations of practical systems regarding transmission resources, this paper introduces a novel approach. It addresses both control signal transmission and triggering conditions, presenting a two-bit-triggered control method aimed at conserving system transmission resources. Additionally, a command filter is incorporated to address the problem of complexity explosion. Furthermore, to model the uncertain nonlinear dynamics affected by time-varying periodic disturbances, this paper combines Fourier series expansion and radial basis function neural networks. Finally, the effectiveness of the proposed methodology is demonstrated through simulation results.
Findings
Based on neural networks and command filter control method, an adaptive two-bit-triggered bipartite control strategy for nonlinear networked MASs is proposed.
Originality/value
The proposed control strategy effectively addresses the challenges of limited transmission resources, nonlinear dynamics and periodic disturbances in networked MASs. It guarantees the boundedness of all signals within the closed-loop system while also ensuring effective bipartite tracking performance.
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The publication of Capital in the Twenty-First Century by Piketty (2014) propelled the debate about the prospects of the evolution of income and wealth inequalities in this…
Abstract
The publication of Capital in the Twenty-First Century by Piketty (2014) propelled the debate about the prospects of the evolution of income and wealth inequalities in this century. One of the main controversies is about the effects on the income and wealth inequalities of a decrease in the growth rate g. In Piketty (2014), it is claimed that a decrease in g will cause an increase in the wealth inequality, through an increase in the difference r−g, where r is the rate of return on capital. This claim was criticized by many authors. In this chapter, the author presents a neoclassical growth model with heterogeneous agents and uses it to shed more light on this issue. The author’s model generalizes and improves previous models introduced in Piketty and Zucman (2015) and in Aoki and Nirei (2016). The author also presents a result, relating income, wealth, and wage inequalities.
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Nasiru Salihu, Poom Kumam, Sulaiman Mohammed Ibrahim and Huzaifa Aliyu Babando
Previous RMIL versions of the conjugate gradient method proposed in literature exhibit sufficient descent with Wolfe line search conditions, yet their global convergence depends…
Abstract
Purpose
Previous RMIL versions of the conjugate gradient method proposed in literature exhibit sufficient descent with Wolfe line search conditions, yet their global convergence depends on certain restrictions. To alleviate these assumptions, a hybrid conjugate gradient method is proposed based on the conjugacy condition.
Design/methodology/approach
The conjugate gradient (CG) method strategically alternates between RMIL and KMD CG methods by using a convex combination of the two schemes, mitigating their respective weaknesses. The theoretical analysis of the hybrid method, conducted without line search consideration, demonstrates its sufficient descent property. This theoretical understanding of sufficient descent enables the removal of restrictions previously imposed on versions of the RMIL CG method for global convergence result.
Findings
Numerical experiments conducted using a hybrid strategy that combines the RMIL and KMD CG methods demonstrate superior performance compared to each method used individually and even outperform some recent versions of the RMIL method. Furthermore, when applied to solve an image reconstruction model, the method exhibits reliable results.
Originality/value
The strategy used to demonstrate the sufficient descent property and convergence result of RMIL CG without line search consideration through hybrid techniques has not been previously explored in literature. Additionally, the two CG schemes involved in the combination exhibit similar sufficient descent structures based on the assumption regarding the norm of the search direction.
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Bushi Chen, Xunyu Zhong, Han Xie, Pengfei Peng, Huosheng Hu, Xungao Zhong and Qiang Liu
Autonomous mobile robots (AMRs) play a crucial role in industrial and service fields. The paper aims to build a LiDAR-based simultaneous localization and mapping (SLAM) system…
Abstract
Purpose
Autonomous mobile robots (AMRs) play a crucial role in industrial and service fields. The paper aims to build a LiDAR-based simultaneous localization and mapping (SLAM) system used by AMRs to overcome challenges in dynamic and changing environments.
Design/methodology/approach
This research introduces SLAM-RAMU, a lifelong SLAM system that addresses these challenges by providing precise and consistent relocalization and autonomous map updating (RAMU). During the mapping process, local odometry is obtained using iterative error state Kalman filtering, while back-end loop detection and global pose graph optimization are used for accurate trajectory correction. In addition, a fast point cloud segmentation module is incorporated to robustly distinguish between floor, walls and roof in the environment. The segmented point clouds are then used to generate a 2.5D grid map, with particular emphasis on floor detection to filter the prior map and eliminate dynamic artifacts. In the positioning process, an initial pose alignment method is designed, which combines 2D branch-and-bound search with 3D iterative closest point registration. This method ensures high accuracy even in scenes with similar characteristics. Subsequently, scan-to-map registration is performed using the segmented point cloud on the prior map. The system also includes a map updating module that takes into account historical point cloud segmentation results. It selectively incorporates or excludes new point cloud data to ensure consistent reflection of the real environment in the map.
Findings
The performance of the SLAM-RAMU system was evaluated in real-world environments and compared against state-of-the-art (SOTA) methods. The results demonstrate that SLAM-RAMU achieves higher mapping quality and relocalization accuracy and exhibits robustness against dynamic obstacles and environmental changes.
Originality/value
Compared to other SOTA methods in simulation and real environments, SLAM-RAMU showed higher mapping quality, faster initial aligning speed and higher repeated localization accuracy.
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Zhongwen Cao, Liang Zhang, Adil M. Ahmad, Fawaz E. Alsaadi and Madini O. Alassafi
This paper aims to investigate an adaptive prescribed performance control problem for switched pure-feedback non-linear systems with input quantization.
Abstract
Purpose
This paper aims to investigate an adaptive prescribed performance control problem for switched pure-feedback non-linear systems with input quantization.
Design/methodology/approach
By using the semi-bounded continuous condition of non-affine functions, the controllability of the system can be guaranteed. Then, a constraint variable method is introduced to ensure that the tracking error satisfies the prescribed performance requirements. Meanwhile, to avoid the design difficulties caused by the input quantization, a non-linear decomposition method is adopted. Finally, the feasibility of the proposed control scheme is verified by a numerical simulation example.
Findings
Based on neural networks and prescribed performance control method, an adaptive neural control strategy for switched pure-feedback non-linear systems is proposed.
Originality/value
The complex deduction and non-differentiable problems of traditional prescribed performance control methods can be solved by using the proposed error transformation approach. Besides, to obtain more general results, the restrictive differentiability assumption on non-affine functions is removed.
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Abstract
Let
Guotao Yang, Yue Wang, Huibin Chang and Qinghua Chen
This study examines the relative efficiencies of anti-poverty policies implemented in 28 Chinese provinces.
Abstract
Purpose
This study examines the relative efficiencies of anti-poverty policies implemented in 28 Chinese provinces.
Design/methodology/approach
This study uses meta-frontier undesirable dynamic two-stage data envelopment analysis. The authors divide the poverty reduction process into two stages: agricultural production and poverty reduction. Public expenditure is the input for the second stage, and the population below the poverty line is the undesirable output. The authors compute the efficiencies (overall efficiency, efficiency of each stage and the efficiencies of individual inputs and outputs) using meta-frontier analysis for the 28 provinces.
Findings
The results show that: (1) a significant imbalance exists between the eastern and western regions in terms of input-output efficiencies; (2) the poverty reduction stage generally fared better than the agricultural production stage did. In particular, most provinces saw increases in poverty reduction efficiencies between 2013 and 2017; (3) the place-based poverty relief policies introduced in recent years are effective at reducing the poverty rate and reaching the government-set goals and (4) while disposable income has increased steadily over the past few years, income inequality has been exacerbated.
Research limitations/implications
The results show that: (1) a significant imbalance exists between the eastern and western regions in terms of input-output efficiencies; (2) the poverty reduction stage generally fared better than the agricultural production stage did. In particular, most provinces saw increases in poverty reduction efficiencies between 2013 and 2017; (3) the place-based poverty relief policies introduced in recent years are effective at reducing the poverty rate and reaching the government-set goals and (4) while disposable income has increased steadily over the past few years, income inequality has exacerbated.
Originality/value
A large amount of attention and public resources are devoted to fighting poverty and associated market failures in China. The extant literature focuses either on the agricultural production itself or the relationship between human capital and productivity levels. Making use of recent developments of the DEA method, the authors propose a new framework for evaluating the efficiencies of the poverty reduction process. Such a framework has the advantage of giving researchers and policymakers a more detailed diagnosis with regard to the components in the endeavor to eliminate poverty and providing useful information for policymakers to optimize public funds use. Methodologically, the framework is flexible enough to be employed for future research in similar appraisals, at different geographic and scale aggregation levels, for public projects including but not limited to poverty reduction.
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The objective of this study is to present a successful strategy to promote Korea as the logistics hub of Northeast Asia. Firstly, we introduce the necessity of a logistic hub…
Abstract
The objective of this study is to present a successful strategy to promote Korea as the logistics hub of Northeast Asia. Firstly, we introduce the necessity of a logistic hub strategy for Korea. In order to develop a successful strategy, we consider the 'free trade zone' model of the Netherlands and China. We develop a realistic and suitable model for Korea based on this Jree trade zone' model. Our proposal for a successful logistic hub strategy for Korea is the fulfillment of the following six objectives: 1) security of market accessibility, 2) improvement of the logistic system, 3) improvement of the education system, 4) improvement of the tax system, 5) assurance of labor market flexibility, and 6) development of an appealing living environment for foreigners.
Godwin Amechi Okeke and Daniel Francis
The authors prove the existence and uniqueness of fixed point of mappings satisfying Geraghty-type contractions in the setting of preordered modular G-metric spaces. The authors…
Abstract
Purpose
The authors prove the existence and uniqueness of fixed point of mappings satisfying Geraghty-type contractions in the setting of preordered modular G-metric spaces. The authors apply the results in solving nonlinear Volterra-Fredholm-type integral equations. The results extend generalize compliment and include several known results as special cases.
Design/methodology/approach
The results of this paper are theoretical and analytical in nature.
Findings
The authors prove the existence and uniqueness of fixed point of mappings satisfying Geraghty-type contractions in the setting of preordered modular G-metric spaces. apply the results in solving nonlinear Volterra-Fredholm-type integral equations. The results extend, generalize, compliment and include several known results as special cases.
Research limitations/implications
The results are theoretical and analytical.
Practical implications
The results were applied to solving nonlinear integral equations.
Social implications
The results has several social applications.
Originality/value
The results of this paper are new.
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Liang Zhang, Changzhu Wei, Yin Diao and Naigang Cui
This paper aims to investigate the problem of on-line orbit planning and guidance for an advanced upper stage.
Abstract
Purpose
This paper aims to investigate the problem of on-line orbit planning and guidance for an advanced upper stage.
Design/methodology/approach
The double impulse optimal transfer orbit is planned by the Lambert algorithm and the improved particle swarm optimization (IPSO) method, which can reduce the total velocity increment of the transfer orbit. More specially, a simplified formula is developed to obtain the working time of the main engine for two phases of flight based on the theorem of impulse. Subsequently, the true anomalies of the start position and the end position for both two phases are planned by the Newton iterative algorithm and the Kepler equation. Finally, the first phase of flight is guided by a novel iterative guidance (NIG) law based on the true anomaly update with respect to the geometrical relationship. Also, a completely analytical powered explicit guidance (APEG) law is presented to realize orbital injection for the second phase of flight.
Findings
Simulations including Monte Carlo and three typical orbit transfer missions are carried out to demonstrate the efficiency of the proposed scheme.
Originality/value
A novel on-line orbit planning algorithm is developed based on the Lambert problem, IPSO optimization method and Newton iterative algorithm. The NIG and APEG are presented to realize the designed transfer orbit for the first and second phases of flight. Both two guidance laws achieve higher orbit injection accuracies than traditional guidance laws.