Xiangjian Chen, Di Li, Zhijun Xu and Yue Bai
Quadrotor micro aerial vehicle (MAV) is nonlinear and under actuated plant, and it is difficult to obtain an accurate mathematical model for quadrotor MAV due to uncertainties…
Abstract
Purpose
Quadrotor micro aerial vehicle (MAV) is nonlinear and under actuated plant, and it is difficult to obtain an accurate mathematical model for quadrotor MAV due to uncertainties. The purpose of this paper is to propose one robust control strategy for quadrotor MAV to accommodate system uncertainties, variations, and external disturbances.
Design/methodology/approach
The robust control strategy is composed of two self‐organizing interval type‐II fuzzy neural networks (SOIT‐IIFNNs) and one PD controller: the PD controller is adopted to control the attitude and position; one of the SOIT‐IIFNNs is designed to learn the inverse model of quadrotor MAV online; the other SOIT‐IIFNNs is the copy of the former one to compensate for model errors, system uncertainties and external disturbances, both structure and parameters of SOIT‐IIFNNs are tuned online at the same time, and then the stability of the resulting quadrotor MAV closed‐loop control system is proved using Lyapunov stability theory.
Findings
The validity of the proposed control method has been verified through real‐time experiments. The experimental results show that the performance of SOIT‐IIFNNs is significantly improved compared with Backstepping‐based controller.
Practical implications
This approach has been used in quadrotor MAV, the controller works well, and it could guarantee quadrotor MAV control system with good performances under uncertainties, variations, and external disturbances.
Originality/value
The proposed SOIT‐IIFNNs controller is interesting for the design of an intelligent control scheme. The main contributions of this paper are: the overall closed‐loop control system is globally stable, demonstrated by Lyapunov stable theory; the tracking error can be asymptotically attenuated to a desired small level around zero by appropriate chosen parameters and learning rates; and the quadrotor MAV control system based on SOIT‐IIFNNs controller can achieve favorable tracking performance.
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Xiangjian Chen, Di Li, Zhijun Xu and Yue Bai
Micro aerial vehicle is nonlinear plant; it is difficult to obtain stable control for MAV attitude due to uncertainties. The purpose of this paper is to propose one robust stable…
Abstract
Purpose
Micro aerial vehicle is nonlinear plant; it is difficult to obtain stable control for MAV attitude due to uncertainties. The purpose of this paper is to propose one robust stable control strategy for MAV to accommodate system uncertainties, variations, and external disturbances.
Design/methodology/approach
First, by employing interval type-II fuzzy neural network (ITIIFNN) to approximate the nonlinearity function and uncertainty functions in the attitude angle dynamic model of micro aircraft vehicle (MAV). Then, the Lyapunov stability theorem is used to testify the asymptotic stability of the closed-loop system, the parameters of the ITIIFNN and gain of sliding mode control can be tuned on-line by adaptive laws based on Lyapunov synthesis approach, and the Lyapunov stability theorem has been used to testify the asymptotic stability of the closed-loop system.
Findings
The validity of the proposed control method has been verified through real-time experiments. The experimental results show that the performance of interval type-II fuzzy neural network based gain adaptive sliding mode controller (GASMC-ITIIFNN) is significantly improved compared with conventional adaptive sliding mode controller (CASMC), type-I fuzzy neural network based sliding mode controller (GASMC-TIFNN).
Practical implications
This approach has been used in one MAV, the controller works well, and which could guarantee the MAV control system with good performances under uncertainties, variations, and external disturbances.
Originality/value
The main original contributions of this paper are: the proposed control scheme makes full use of the nominal model of the MAV attitude control model; the overall closed-loop control system is globally stable demonstrated by Lyapunov stable theory; the tracking error can be asymptotically attenuated to a desired small level around zero by appropriate chosen parameters and learning rates; and the MAV attitude control system based on GASMC-ITIIFNN controller can achieve favourable tracking performance than GASMC-TIFNN and CASMC.
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ZhiJun Xu, Xiaobing Liu, Chunguang Bai and Lijie Hu
As green marketing is a critical function of green supply chain management, it has generated a great deal of discussion in public discourse and academic research. Interestingly…
Abstract
As green marketing is a critical function of green supply chain management, it has generated a great deal of discussion in public discourse and academic research. Interestingly, there is a gap in the research on how a company can effectively invest and manage various green marketing activities. Thus this paper aims to introduce a grey multiple criteria decision-making methodology to investigate the relationships between green marketing activities and performance outcomes (environmental and business performance). This paper seeks to make the following contributions to the green supply chain management literature. First, review the literature to identify implementation activities for green marketing from green supply chain management literature. Second, develop a methodology to evaluate relationships of green marketing activities by integrating grey number and rough set method. Third, obtain various decision rules relating the various green marketing activities to the environmental and/or business performance outcomes through an illustrative application within an incomplete information system. Knowing those rules to help in the implementation, management, and evaluation of these green marketing activities is valuable to both researchers and practitioners. Included in the discussion are insights into how these rules for individual and aggregated performance (environmental, business, and joint performance) may be evaluated. Practical and research implications of this work are detailed in the final section of this paper.
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The paper aims to identify the challenges faced by Huawei Technologies, China's biggest telecommunications equipment manufacturer, as it makes the transition from an…
Abstract
Purpose
The paper aims to identify the challenges faced by Huawei Technologies, China's biggest telecommunications equipment manufacturer, as it makes the transition from an indigenously‐owned business to a potentially competitive global giant.
Design/methodology/approach
This is an inductive, interpretative case study complimented by hands‐on experience with the industry.
Findings
The paper finds that Huawei lies at a crossroads in a transitional telecommunication sector that is no longer isolated from global reforms and advancement. Through internationalisation the company has learned to compete by adjusting their mechanisms, learning instruments and focus.
Originality/value
The paper is useful for practitioners in that it shows how indigenous companies in latecomer industrialising countries like China can overcome the late mover position in some of the advanced markets they have entered. For academics it highlights the role of government in helping to construct competitive indigenous firms that could take on global giants.
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Shuntao Liu, Zhixiong Yang, Zhijun Zhu, Liangliang Han, Xiangyang Zhu and Kai Xu
Slim and dexterous manipulators with long reaches can perform various exploration and inspection tasks in confined spaces. This paper aims to present the development of such a…
Abstract
Purpose
Slim and dexterous manipulators with long reaches can perform various exploration and inspection tasks in confined spaces. This paper aims to present the development of such a dexterous continuum manipulator for potential applications in the aviation industry.
Design/methodology/approach
Benefiting from a newly conceived dual continuum mechanism and the improved actuation scheme, this paper proposes a design of a slim and dexterous continuum manipulator. Kinematics modeling, simulation-based dimension synthesis, structural constructions and system descriptions are elaborated.
Findings
Experimental validations show that the constructed prototype possesses the desired dexterity to navigate through confined spaces with its kinematics calibrated and actuation compensation implemented. The continuum manipulator with different deployed tools (e.g. graspers and welding guns) would be able to perform inspections and other tasks at remote locations in constrained environments.
Research limitations/implications
The current construction of the continuum manipulator possesses quite some friction inside its structure. The bending discrepancy caused by friction could accumulate to an obvious level. It is desired to further reduce the friction, even though the actuation compensation had been implemented.
Practical implications
The constructed continuum manipulator could perform inspection and other tasks in confined spaces, acting as an active multi-functional endoscopic platform. Such a device could greatly facilitate routine tasks in the aviation industry, such as guided assembling, inspection and maintenance.
Originality/value
The originality and values of this paper mainly lay on the design, modeling, construction and experimental validations of the slim and dexterous continuum manipulator for the desired mobility and functionality in confined spaces.
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Huihuang Zhao, Jianzhen Chen, Shibiao Xu, Ying Wang and Zhijun Qiao
The purpose of this paper is to develop a compressive sensing (CS) algorithm for noisy solder joint imagery compression and recovery. A fast gradient-based compressive sensing…
Abstract
Purpose
The purpose of this paper is to develop a compressive sensing (CS) algorithm for noisy solder joint imagery compression and recovery. A fast gradient-based compressive sensing (FGbCS) approach is proposed based on the convex optimization. The proposed algorithm is able to improve performance in terms of peak signal noise ratio (PSNR) and computational cost.
Design/methodology/approach
Unlike traditional CS methods, the authors first transformed a noise solder joint image to a sparse signal by a discrete cosine transform (DCT), so that the reconstruction of noisy solder joint imagery is changed to a convex optimization problem. Then, a so-called gradient-based method is utilized for solving the problem. To improve the method efficiency, the authors assume the problem to be convex with the Lipschitz gradient through the replacement of an iteration parameter by the Lipschitz constant. Moreover, a FGbCS algorithm is proposed to recover the noisy solder joint imagery under different parameters.
Findings
Experiments reveal that the proposed algorithm can achieve better results on PNSR with fewer computational costs than classical algorithms like Orthogonal Matching Pursuit (OMP), Greedy Basis Pursuit (GBP), Subspace Pursuit (SP), Compressive Sampling Matching Pursuit (CoSaMP) and Iterative Re-weighted Least Squares (IRLS). Convergence of the proposed algorithm is with a faster rate O(k*k) instead of O(1/k).
Practical implications
This paper provides a novel methodology for the CS of noisy solder joint imagery, and the proposed algorithm can also be used in other imagery compression and recovery.
Originality/value
According to the CS theory, a sparse or compressible signal can be represented by a fewer number of bases than those required by the Nyquist theorem. The new development might provide some fundamental guidelines for noisy imagery compression and recovering.
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Zhijun Wang, Hezeng Li and Jingyuan Zhang
In a mobile ad hoc network (MANET), design of energy‐efficient routing schemes is essential for prolonging the network lifetime. The purpose of this paper is to show that one way…
Abstract
Purpose
In a mobile ad hoc network (MANET), design of energy‐efficient routing schemes is essential for prolonging the network lifetime. The purpose of this paper is to show that one way to achieve energy efficiency in routing is to utilize location information, which becomes practical due to the recent increasing availability of low‐cost and reliable positioning devices.
Design/methodology/approach
This paper proposes an eight‐direction forwarding virtual grid aided (VGA) routing scheme that uses location information to save energy. As a grid‐based scheme, VGA divides the whole network area into virtual grids.
Findings
By using eight‐direction forwarding, the proposed VGA scheme outperforms the previous four‐direction forwarding geographical adaptive fidelity (GAF) protocol. The proposed VGA scheme is motivated by the fact that, in the GAF protocol, forwarding to the four diagonal neighboring grids cannot be done in one single hop, although most nodes in these grids can hear the signal.
Originality/value
Theoretical analysis shows the eight‐direction forwarding protocol performs better than the four‐direction one unless the forwarding direction has an angle of less than 15○ with the horizontal or vertical grid axis. Simulation supports the fact that the eight‐direction forwarding VGA scheme has better energy performance than the four‐direction forwarding GAF scheme without sacrificing any routing performance.
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Silu Pang, Guihong Hua and Zhijun Yan
This study investigates the heterogeneous impact of R&D capital market distortions (CMDs) on the quantity and quality of innovation in Chinese firms by exploring key pathways from…
Abstract
Purpose
This study investigates the heterogeneous impact of R&D capital market distortions (CMDs) on the quantity and quality of innovation in Chinese firms by exploring key pathways from a dual-arbitrage perspective.
Design/methodology/approach
Using data from Chinese A-share listed companies (2015–2021), we employ a multidimensional fixed effects model to validate the research hypotheses. Under the Systems of National Accounts (SNA, 2008) framework, we use the Bureau of Economic Analysis method to estimate enterprise R&D capital stock and the Cobb-Douglas production function to estimate R&D CMDs.
Findings
Results show that R&D CMDs drive firms toward strategic innovation, emphasizing quantity over quality. Policy arbitrage, including policy catering and rent-seeking, emerges as a pivotal mechanism under R&D CMDs, encouraging firms to prioritize quantity over quality in innovation. High-technology firms and those in the decline stage are more inclined to spearhead strategic innovation within the context of R&D CMDs.
Practical implications
These findings help policymakers promote high-quality innovation in Chinese enterprises by enhancing patent review mechanisms and shifting policies from quantity-driven to quality-oriented goals.
Originality/value
This study enriches the research on factor market distortions and innovation in emerging markets from the perspective of R&D CMDs, based on the “emerging + transitional” comprehensive framework. Unlike previous studies, which generally use enterprise R&D expenditure flow data, we apply the theory of R&D capitalization accounting to the micro-enterprise level under the SNA (2008) framework, enhancing the accuracy of R&D CMD estimations.
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Lichao Zhu, Hangzhou Yang and Zhijun Yan
The purpose of this paper is to develop a new method to extract medical temporal information from online health communities.
Abstract
Purpose
The purpose of this paper is to develop a new method to extract medical temporal information from online health communities.
Design/methodology/approach
The authors trained a conditional random-filed model for the extraction of temporal expressions. The temporal relation identification is considered as a classification task and several support vector machine classifiers are built in the proposed method. For the model training, the authors extracted some high-level semantic features including co-reference relationship of medical concepts and the semantic similarity among words.
Findings
For the extraction of TIMEX, the authors find that well-formatted expressions are easy to recognize, and the main challenge is the relative TIMEX such as “three days after onset”. It also shows the same difficulty for normalization of absolute date or well-formatted duration, whereas frequency is easier to be normalized. For the identification of DocTimeRel, the result is fairly well, and the relation is difficult to identify when it involves a relative TIMEX or a hypothetical concept.
Originality/value
The authors proposed a new method to extract temporal information from the online clinical data and evaluated the usefulness of different level of syntactic features in this task.
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Qingyi Li, Hong Zhu, Yayu Zhou, Zhijun Li and Chunqu Xiao
The purpose of this study is to assist brand and product managers in selecting appropriate ingredient names for environmentally friendly products. It investigates the effects of…
Abstract
Purpose
The purpose of this study is to assist brand and product managers in selecting appropriate ingredient names for environmentally friendly products. It investigates the effects of unfamiliar ingredients on consumers’ evaluations of environmental friendliness and their purchase intentions, based on the cue consistency theory.
Design/methodology/approach
Five experimental studies (n = 968) were conducted to achieve the research objectives. Study 1 found that consumers tended to avoid choosing unfamiliar ingredients. Study 2 examined the impact of ingredient familiarity on consumers’ perceived greenness. Study 3 investigated the mediating role of perceived naturalness. Studies 4 and 5, respectively, explored the moderating effects of emphasizing the importance of technology in environmental conservation and product category.
Findings
The findings indicate that when environmentally friendly products are labeled with unfamiliar ingredients (vs. familiar), consumers’ perceived greenness and purchase intentions decrease. This effect is mediated by perceived naturalness. Moreover, the negative impact of unfamiliar ingredients is mitigated by emphasizing the importance of technology and the high-tech product category.
Originality/value
This paper reveals the unique role of unfamiliar ingredients in shaping consumer attitudes toward environmentally friendly products. Based on cue consistency theory, it uncovers how unfamiliar ingredients influence the perceived greenness of environmentally friendly products through perceived naturalness. Furthermore, the paper demonstrates the impact of emphasizing the importance of technology (emphasis vs. control) and product category (high-tech vs. low-tech) on consumer attitudes and behaviors toward environmentally friendly products.