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Article
Publication date: 2 October 2017

Zhi Chen, Daobo Wang, Ziyang Zhen, Biao Wang and Jian Fu

This paper aims to present a control strategy that eliminates the longitudinal and lateral drifting movements of the coaxial ducted fan unmanned helicopter (UH) during autonomous…

307

Abstract

Purpose

This paper aims to present a control strategy that eliminates the longitudinal and lateral drifting movements of the coaxial ducted fan unmanned helicopter (UH) during autonomous take-off and landing and reduce the coupling characteristics between channels of the coaxial UH for its special model structure.

Design/methodology/approach

Unidirectional auxiliary surfaces (UAS) for terminal sliding mode controller (TSMC) are designed for the flight control system of the coaxial UH, and a hierarchical flight control strategy is proposed to improve the decoupling ability of the coaxial UH.

Findings

It is demonstrated that the proposed height control strategy can solve the longitudinal and lateral movements during autonomous take-off and landing phase. The proposed hierarchical controller can decouple vertical and heading coupling problem which exists in coaxial UH. Furthermore, the confronted UAS-TSMC method can guarantee finite-time convergence and meet the quick flight trim requirements during take-off and landing.

Research limitations/implications

The designed flight control strategy has not implemented in real flight test yet, as all the tests are conducted in the numerical simulation and simulation with a hardware-in-the-loop (HIL) platform.

Social implications

The designed flight control strategy can solve the common problem of coupling characteristics between channels for coaxial UH, and it has important theoretical basis and reference value for engineering application; the control strategy can meet the demands of engineering practice.

Originality/value

In consideration of the TSMC approach, which can increase the convergence speed of the system state effectively, and the high level of response speed requirements to UH flight trim, the UAS-TSMC method is first applied to the coaxial ducted fan UH flight control. The proposed control strategy is implemented on the UH flight control system, and the HIL simulation clearly demonstrates that a much better performance could be achieved.

Details

Aircraft Engineering and Aerospace Technology, vol. 89 no. 6
Type: Research Article
ISSN: 1748-8842

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Article
Publication date: 7 August 2019

Jian-Ming Fu, Hai-Min Tang and Hong-Quan Chen

The purpose of this paper is to develop a new approach for rapid computation of subsonic and low-transonic rotary derivatives with the available steady solutions obtained by Euler…

86

Abstract

Purpose

The purpose of this paper is to develop a new approach for rapid computation of subsonic and low-transonic rotary derivatives with the available steady solutions obtained by Euler computational fluid dynamics (CFD) codes.

Design/methodology/approach

The approach is achieved by the perturbation on the steady-state pressure of Euler CFD codes. The resulting perturbation relation is established at a reference Mach number between rotary derivatives and normal velocity on surface due to angular velocity. The solution of the reference Mach number is generated technically by Prandtl–Glauert compressibility correction based on any Mach number of interest under the assumption of simple strip theory. Rotary derivatives of any Mach number of interest are then inversely predicted by the Prandtl–Glauert rule based on the reference Mach number aforementioned.

Findings

The resulting method has been verified for three typical different cases of the Basic Finner Reference Projectile, the Standard Dynamics Model Aircraft and the Orion Crew Module. In comparison with the original perturbation method, the performance at subsonic and low-transonic Mach numbers has significantly improved with satisfactory accuracy for most design efforts.

Originality/value

The approach presented is verified to be an efficient way for computation of subsonic and low-transonic rotary derivatives, which are performed almost at the same time as an accounting solution of steady Euler equations.

Details

Engineering Computations, vol. 36 no. 9
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 17 August 2012

Jian Fu, Wen‐hua Chen and Qing‐xian Wu

This article proposes a chattering‐free sliding mode control scheme with unidirectional auxiliary surfaces (UAS‐SMC) for small miniature autonomous helicopters (Trex 250).

240

Abstract

Purpose

This article proposes a chattering‐free sliding mode control scheme with unidirectional auxiliary surfaces (UAS‐SMC) for small miniature autonomous helicopters (Trex 250).

Design/methodology/approach

The proposed UAS‐SMC scheme consists of a nested sequence of rotor dynamics, angular rate, Euler angle, velocity and position loops.

Findings

It is demonstrated that the UAS‐SMC strategy can eliminate the chattering phenomenon exhibiting in the convenient SMC method and achieve a better approaching speed.

Originality/value

The proposed control strategy is implemented on the helicopter and flight tests clearly demonstrate that a much better performance could be achieved, compared with convenient SMC schemes.

Details

International Journal of Intelligent Computing and Cybernetics, vol. 5 no. 3
Type: Research Article
ISSN: 1756-378X

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Article
Publication date: 21 August 2009

Lianyu Fu, Jian Li and Fan Yang

The purpose of this paper is to provide a method and system to achieve automated measurement of micro drill bit wear.

356

Abstract

Purpose

The purpose of this paper is to provide a method and system to achieve automated measurement of micro drill bit wear.

Design/methodology/approach

A method and system of automated measurement of micro drill bit wear on the basis of machine vision are presented. Experiments are conducted to verify the developed method and system.

Findings

The worn area of the primary face is an appropriate index to reflect the wear condition of a micro drill bit. A machine vision based technique is an applicable tool for capturing and characterising images of worn micro drill bit. The developed system can accurately measure and characterise the wear performance of micro drill bits with different materials and different parameter designs.

Originality/value

The paper highlights the method and the system for achieving automated measurement of micro drill bit wear. The developed method and system can provide fast and precise evaluation of micro drill bit wear.

Details

Circuit World, vol. 35 no. 3
Type: Research Article
ISSN: 0305-6120

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Article
Publication date: 16 July 2024

Wei Qian, Carol Tilt and Ping Zhu

This paper aims to examine the role of local/provincial government in influencing corporate social and environmental reporting (CSER) in China, and more specifically, how the…

106

Abstract

Purpose

This paper aims to examine the role of local/provincial government in influencing corporate social and environmental reporting (CSER) in China, and more specifically, how the underlying economic and political factors associated with local government have influenced the quality of CSER.

Design/methodology/approach

The authors used 234 environmentally sensitive companies listed on the Shanghai and Shenzhen Stock Exchanges during 2013 and 2015 as the research sample to test the relationship between CSER and local government’s political connection and economic prioritisation and the potential mediating effect of local economic prioritisation.

Findings

The analysis provides evidence that local/provincial government’s political geographical connectedness with the central government has directly and positively influenced the level of CSER, while local prioritisation of economic development has a direct but negative effect on CSER in China. In addition, local/provincial prioritisation of economic development has mediated the relationship between local–central political geographical connectedness and CSER.

Practical implications

While local/provincial governments are heavily influenced by the coercive pressure from the central government, they also act in their own political and economic interests in overseeing CSER at the local level. This study raises the question about the effectiveness of the top-down approach to improving CSER in China and suggests that the central government may need to focus more on coordinating and harmonising different local/provincial governments’ interests to enable achieving a common sustainability goal.

Originality/value

The authors provide evidence revealing how the economic and political contexts of local government have played a significant role in shaping CSER in China. More specifically, this paper addresses a gap in the literature by highlighting the importance of local government oversight power for CSER development and how such oversight is determined by local prioritisation of economic development and political geographical connectedness of local and central governments.

Details

Meditari Accountancy Research, vol. 32 no. 6
Type: Research Article
ISSN: 2049-372X

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Article
Publication date: 25 April 2008

John Chi‐kin Lee, Daoyong Ding and Huan Song

The purpose of this paper is to discuss recent developments in school developmental supervisory evaluation in the Pudong New Area of Shanghai in the Chinese Mainland.

3387

Abstract

Purpose

The purpose of this paper is to discuss recent developments in school developmental supervisory evaluation in the Pudong New Area of Shanghai in the Chinese Mainland.

Design/methodology/approach

The main research approach is qualitative, using documentary analysis and interviews of an inspector, principals and teachers from two primary schools.

Findings

There were perceived positive and negative impacts of school supervision and evaluation.

Originality/value

The paper highlights the implications for fostering a shared school‐government community of school supervision and evaluation, promoting a dynamic approach for addressing contextual differences as well as achieving better coherence among educational reform, supervision and evaluation policies.

Details

Quality Assurance in Education, vol. 16 no. 2
Type: Research Article
ISSN: 0968-4883

Keywords

Available. Content available
Article
Publication date: 18 November 2013

Martin Goosey

211

Abstract

Details

Circuit World, vol. 39 no. 4
Type: Research Article
ISSN: 0305-6120

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Book part
Publication date: 6 November 2013

Feng Yang, Qianqian Yuan, Zhimin Huang and Liang Liang

The current chapter is a tentative step toward investigating the allocation of advertising budget between the internet platform and the entity platform according to the long-term…

Abstract

The current chapter is a tentative step toward investigating the allocation of advertising budget between the internet platform and the entity platform according to the long-term and short-term achievement of advertising investment. We provide a decision-making framework on how to allocate the advertising budget to the two platforms for the best results. The integrated effect of advertising investment consists of two parts. Goodwill and customer scale reflect the long-term achievement, and sale profit represents the short-term achievement. We selected some representative feasible investment plans as decision-making units (DMUs), and calculated the values of sale profit, goodwill, and customer scale as three outputs. To determine the best advertising investment plan, we use data envelopment analysis (DEA) model to seek efficient plans, and then determine the best one from those efficient plans through preference investigation and super-efficiency technique.

Details

Applications of Management Science
Type: Book
ISBN: 978-1-78190-956-0

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Article
Publication date: 2 October 2023

Beatriz Lopes Cancela, Arnaldo Coelho and Maria Elisabete Neves

This study aims to investigate the role of green strategic alliances (GSAs) in fostering a green shared vision (GSVis) and green shared value (GSV) and their impact on green…

501

Abstract

Purpose

This study aims to investigate the role of green strategic alliances (GSAs) in fostering a green shared vision (GSVis) and green shared value (GSV) and their impact on green organizational identity (GOI) and sustainability.

Design/methodology/approach

The authors employed structural equation modeling to analyze data collected through a 60-item questionnaire administered in Portugal and China, allowing the authors to test their theoretical model.

Findings

The findings of the authors' study indicate that green strategic alliances have a positive influence on the development of a GSVis and GSV in both countries. This, in turn, contributes to improved sustainability and the establishment of a GOI. Furthermore, the authors' results demonstrate that these alliances enhance GSV, resulting in enhanced sustainability performance and a stronger green identity, with a notable increase in awareness of environmental and social practices.

Originality/value

This article is innovative as it applies organizational learning and value creation theories to gain a deeper understanding of how alliances can shape the green identity of companies and contribute to their overall sustainability.

Details

Benchmarking: An International Journal, vol. 31 no. 10
Type: Research Article
ISSN: 1463-5771

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Article
Publication date: 6 September 2022

Elena Fedorova, Pavel Drogovoz, Anna Popova and Vladimir Shiboldenkov

The paper examines whether, along with the financial performance, the disclosure of research and development (R&D) expenses, patent portfolios, patent citations and innovation…

271

Abstract

Purpose

The paper examines whether, along with the financial performance, the disclosure of research and development (R&D) expenses, patent portfolios, patent citations and innovation activities affect the market capitalization of Russian companies.

Design/methodology/approach

The paper opted for a set of techniques including bag-of-words (BoW) to retrieve additional innovation-related data from companies' annual reports, self-organizing maps (SOM) to perform visual exploratory analysis and panel data regression (PDR) to conduct confirmatory analysis using data on 74 Russian publicly traded companies for the period 2013–2019.

Findings

The paper observes that the disclosure of nonfinancial data on R&D, patents and primarily product and marketing innovations positively affects the market capitalization of the largest Russian companies, which are mainly focused on energy, raw materials and utilities and are operating on international markets. The study suggests that these companies are financially well-resourced to innovate at risk and thus to provide positive signals to stakeholders and external agents.

Research limitations/implications

Our findings are important to management, investors, financial analysts, regulators and various agencies providing guidance on corporate governance and sustainability reporting. However, the authors acknowledge that the research results may lack generalizability due to the sample covering a single national context. Researchers are encouraged to test the proposed approach further on other countries' data by using the compiled lexicons.

Originality/value

The study aims to expand the domains of signaling theory and market valuation by providing new insights into the impact that companies' reporting on R&D, patents and innovation activities has on market capitalization. New nonfinancial factors that previous research does not investigate – innovation disclosure indicators (IDI) – are tested.

Details

Kybernetes, vol. 52 no. 12
Type: Research Article
ISSN: 0368-492X

Keywords

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