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Article
Publication date: 1 January 1983

R.G.B. Fyffe

This book is a policy proposal aimed at the democratic left. It is concerned with gradual but radical reform of the socio‐economic system. An integrated policy of industrial and…

11006

Abstract

This book is a policy proposal aimed at the democratic left. It is concerned with gradual but radical reform of the socio‐economic system. An integrated policy of industrial and economic democracy, which centres around the establishment of a new sector of employee‐controlled enterprises, is presented. The proposal would retain the mix‐ed economy, but transform it into a much better “mixture”, with increased employee‐power in all sectors. While there is much of enduring value in our liberal western way of life, gross inequalities of wealth and power persist in our society.

Details

International Journal of Sociology and Social Policy, vol. 3 no. 1/2
Type: Research Article
ISSN: 0144-333X

Keywords

Article
Publication date: 12 May 2022

Syed Awais Ali Shah, Bingtuan Gao, Ajeet Kumar Bhatia, Chuande Liu and Arshad Rauf

Barge-type offshore floating wind turbine (OFWT) commonly exhibits an under-actuated phenomenon in an offshore environment, which leads to a potential vibration-damping hazard…

Abstract

Purpose

Barge-type offshore floating wind turbine (OFWT) commonly exhibits an under-actuated phenomenon in an offshore environment, which leads to a potential vibration-damping hazard. This article aims to provide a new robust output feedback anti-vibrational control scheme for the novel translational oscillator with rotational actuator (TORA) based five-degrees of freedom (5-DOF) barge-type OFWT in the presence of unwanted disturbances and modeling uncertainties.

Design/methodology/approach

In this paper, an active control technique called TORA has been used to design a 5-DOF barge-type OFWT model, where the mathematical model of the proposed system is derived by using Euler–Lagrange's equations. The robust hierarchical backstepping integral nonsingular terminal sliding mode control (HBINTSMC) with an adaptive gain is used in conjunction with extended order high gain observer (EHGO) to achieve system stabilization in the presence of unwanted disturbances and modeling uncertainties. The numerical simulations based on MATLAB/SIMULINK have been performed to demonstrate the feasibility and effectiveness of the proposed model and control law.

Findings

The numerical simulation results affirm the accuracy and efficiency of the proposed control law for the TORA based OFWT system. The results demonstrate that the proposed control law is robust against unwanted disturbances and uncertainties. The unknown states are accurately estimated by EHGO which enables the controller to exhibit improved stabilization performance.

Originality/value

A new mathematical model of the 5-DOF barge-type OFWT system based on TORA is the major contribution of this research paper. Furthermore, it provides a new adaptive anti-vibration control scheme by incorporating the EHGO for the proposed model.

Book part
Publication date: 10 December 2015

Chun Kit Lok

Smart card-based E-payment systems are receiving increasing attention as the number of implementations is witnessed on the rise globally. Understanding of user adoption behavior…

Abstract

Smart card-based E-payment systems are receiving increasing attention as the number of implementations is witnessed on the rise globally. Understanding of user adoption behavior of E-payment systems that employ smart card technology becomes a research area that is of particular value and interest to both IS researchers and professionals. However, research interest focuses mostly on why a smart card-based E-payment system results in a failure or how the system could have grown into a success. This signals the fact that researchers have not had much opportunity to critically review a smart card-based E-payment system that has gained wide support and overcome the hurdle of critical mass adoption. The Octopus in Hong Kong has provided a rare opportunity for investigating smart card-based E-payment system because of its unprecedented success. This research seeks to thoroughly analyze the Octopus from technology adoption behavior perspectives.

Cultural impacts on adoption behavior are one of the key areas that this research posits to investigate. Since the present research is conducted in Hong Kong where a majority of population is Chinese ethnicity and yet is westernized in a number of aspects, assuming that users in Hong Kong are characterized by eastern or western culture is less useful. Explicit cultural characteristics at individual level are tapped into here instead of applying generalization of cultural beliefs to users to more accurately reflect cultural bias. In this vein, the technology acceptance model (TAM) is adapted, extended, and tested for its applicability cross-culturally in Hong Kong on the Octopus. Four cultural dimensions developed by Hofstede are included in this study, namely uncertainty avoidance, masculinity, individualism, and Confucian Dynamism (long-term orientation), to explore their influence on usage behavior through the mediation of perceived usefulness.

TAM is also integrated with the innovation diffusion theory (IDT) to borrow two constructs in relation to innovative characteristics, namely relative advantage and compatibility, in order to enhance the explanatory power of the proposed research model. Besides, the normative accountability of the research model is strengthened by embracing two social influences, namely subjective norm and image. As the last antecedent to perceived usefulness, prior experience serves to bring in the time variation factor to allow level of prior experience to exert both direct and moderating effects on perceived usefulness.

The resulting research model is analyzed by partial least squares (PLS)-based Structural Equation Modeling (SEM) approach. The research findings reveal that all cultural dimensions demonstrate direct effect on perceived usefulness though the influence of uncertainty avoidance is found marginally significant. Other constructs on innovative characteristics and social influences are validated to be significant as hypothesized. Prior experience does indeed significantly moderate the two influences that perceived usefulness receives from relative advantage and compatibility, respectively. The research model has demonstrated convincing explanatory power and so may be employed for further studies in other contexts. In particular, cultural effects play a key role in contributing to the uniqueness of the model, enabling it to be an effective tool to help critically understand increasingly internationalized IS system development and implementation efforts. This research also suggests several practical implications in view of the findings that could better inform managerial decisions for designing, implementing, or promoting smart card-based E-payment system.

Details

E-services Adoption: Processes by Firms in Developing Nations
Type: Book
ISBN: 978-1-78560-709-7

Keywords

Article
Publication date: 3 November 2020

Taki Eddine Lechekhab, Stojadin Manojlovic, Momir Stankovic, Rafal Madonski and Slobodan Simic

The control of a quadrotor unmanned aerial vehicle (UAV) is a challenging problem because of its highly nonlinear dynamics, under-actuated nature and strong cross-couplings. To…

Abstract

Purpose

The control of a quadrotor unmanned aerial vehicle (UAV) is a challenging problem because of its highly nonlinear dynamics, under-actuated nature and strong cross-couplings. To solve this problem, this paper aims to propose a robust control strategy, based on a concept of active disturbance rejection control (ADRC).

Design/methodology/approach

The altitude/attitude dynamics of a quadrotor is reformulated into the ADRC framework. Three distinct variations of the error-based ADRC algorithms, with different structures of generalized extended state observers (GESO), are derived for the altitude/attitude trajectory-following task. The convergence of the observation part is proved based on the singular perturbation theory. Through a frequency analysis and a quantitative comparison in a simulated environment, each design is shown to have certain advantages and disadvantages in terms of tracking accuracy and robustness. The digital prototypes of the proposed controllers for quadrotor altitude and attitude control channels are designed and validated through real-time hardware-in-the-loop (HIL) co-simulation, with field-programmable gate array (FPGA) hardware.

Findings

The effects of unavailable reference time-derivatives can be estimated by the ESO and rejected through the outer control loop. The higher order ESOs demonstrate better performances, but with reductions of stability margins. Time-domain simulation analysis reveals the benefits of the proposed control structure related to classical control approach. Real-time FPGA-based HIL co-simulations validated the performances of the considered digital controllers in typical quadrotor flight scenarios.

Practical implications

The conducted study forms a set of practical guidelines for end-users for selecting specific ADRC design for quadrotor control depending on the given control objective and work conditions. Furthermore, the paper presents detailed procedure for the design, simulation and validation of the embedded FPGA-based quadrotor control unit.

Originality/value

In light of the currently available literature on error-based ADRC, a comprehensive approach is applied here, which includes the design of error-based ADRC with different GESOs, its frequency-domain and time-domain analyses using different simulation of UAV flight scenarios, as well as its FPGA-based implementation and testing on the real hardware.

Article
Publication date: 6 May 2022

Lijia Cao, Xu Yang, Guoqing Wang, Yang Liu and Yu Hu

The purpose of this paper is to present an actuator fault detection method for unmanned aerial vehicles (UAVs) based on interval observer and extended state observer.

Abstract

Purpose

The purpose of this paper is to present an actuator fault detection method for unmanned aerial vehicles (UAVs) based on interval observer and extended state observer.

Design/methodology/approach

The proposed algorithm has very little model dependency. Therefore, a six-degree-of-freedom linear equation of UAVs is first established, and then, combined with actuator failure and external disturbances in flight control, a steering gear model with actuator failure (such as stuck bias and invalidation) is designed. Meanwhile, an extended state observer is designed for fault detection. Moreover, a fault detection scheme based on interval observer is designed by combining fault and disturbances.

Findings

The method is testified on the extended state observer and the interval observer under the failure of the steering gear and bounded disturbances. The simulation results show that the two types of fault detection schemes designed can successfully detect various types of faults and have high sensitivity.

Originality/value

This research paper studies the failure detection scheme of the UAVs’ actuator. The fault detection scheme in this paper has better performance on actuator faults and bounded disturbances than using regular fault detection schemes.

Details

Aircraft Engineering and Aerospace Technology, vol. 94 no. 10
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 2 November 2021

Nigar Ahmed and Syed Awais Ali Shah

In this research paper, an adaptive output-feedback robust active disturbance rejection control (RADRC) is designed for the multiple input multiple output (MIMO) quadrotor…

Abstract

Purpose

In this research paper, an adaptive output-feedback robust active disturbance rejection control (RADRC) is designed for the multiple input multiple output (MIMO) quadrotor attitude model subject to unwanted uncertainties and disturbances (UUDs).

Design/methodology/approach

In order to achieve the desired control objectives in the presence of UUDs, the low pass filter (LPF) and extended high gain observer (EHGO) methods are used for the estimation of matched and mismatched UUDs, respectively. Furthermore, for solving the chattering incurred in the standard sliding mode control (SMC), a multilayer sliding mode surface is constructed. For formulating the adaptive output-feedback RADRC algorithm, the EHGO, LPF and SMC schemes are combined using the separation principle.

Findings

The findings of this research work include the design of an adaptive output-feedback RADRC with the ability to negate the UUDs as well as estimate the unknown states of the quadrotor attitude model. In addition, the chattering problem is addressed by designing a modified SMC scheme based on the multilayer sliding mode surface obtained by utilizing the estimated state variables. This sliding mode surface is also used to obtain the adaptive criteria for the switching design gain parameters involved in the SMC. Moreover, the requirement of high design gain parameters in the EHGO is solved by combining it with the LPF.

Originality/value

Designing the flight control techniques while assuming that the state variables are available is a common practice. In addition, to obtain robustness, the SMC technique is widely used. However, in practice, the state variables might not be available due to unknown parameters and uncertainties, as well as the chattering due to SMC reduces the performances of the actuators. Hence, in this paper, an adaptive output-feedback RADRC technique is designed to solve the problems of UUDs and chattering.

Details

Engineering Computations, vol. 39 no. 4
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 1 July 2005

Sujatha Perera, Jill McKinnon and Graeme Harrison

This paper uses a stakeholder approach to examine how the role of accounting and the status of accountants changed over a 30 year period (1970 to 2000) in a major Australian…

5346

Abstract

This paper uses a stakeholder approach to examine how the role of accounting and the status of accountants changed over a 30 year period (1970 to 2000) in a major Australian government trading enterprise. Data are gathered from semi‐structured interviews with organizational participants and documentation. The study provides support for the importance of stakeholders in shaping organizational processes and practices, including accounting practices, and for the effects of changes in stakeholder constituency and agenda on such practices. The study also provides evidence of the roles accounting and accountants may play in implementing a stakeholder agenda, including both instrumental and symbolic roles, and how the status of accountants may rise and fall commensurate with those roles.

Details

Pacific Accounting Review, vol. 17 no. 2
Type: Research Article
ISSN: 0114-0582

Keywords

Article
Publication date: 1 March 1992

John Conway O'Brien

A collection of essays by a social economist seeking to balanceeconomics as a science of means with the values deemed necessary toman′s finding the good life and society enduring…

1155

Abstract

A collection of essays by a social economist seeking to balance economics as a science of means with the values deemed necessary to man′s finding the good life and society enduring as a civilized instrumentality. Looks for authority to great men of the past and to today′s moral philosopher: man is an ethical animal. The 13 essays are: 1. Evolutionary Economics: The End of It All? which challenges the view that Darwinism destroyed belief in a universe of purpose and design; 2. Schmoller′s Political Economy: Its Psychic, Moral and Legal Foundations, which centres on the belief that time‐honoured ethical values prevail in an economy formed by ties of common sentiment, ideas, customs and laws; 3. Adam Smith by Gustav von Schmoller – Schmoller rejects Smith′s natural law and sees him as simply spreading the message of Calvinism; 4. Pierre‐Joseph Proudhon, Socialist – Karl Marx, Communist: A Comparison; 5. Marxism and the Instauration of Man, which raises the question for Marx: is the flowering of the new man in Communist society the ultimate end to the dialectical movement of history?; 6. Ethical Progress and Economic Growth in Western Civilization; 7. Ethical Principles in American Society: An Appraisal; 8. The Ugent Need for a Consensus on Moral Values, which focuses on the real dangers inherent in there being no consensus on moral values; 9. Human Resources and the Good Society – man is not to be treated as an economic resource; man′s moral and material wellbeing is the goal; 10. The Social Economist on the Modern Dilemma: Ethical Dwarfs and Nuclear Giants, which argues that it is imperative to distinguish good from evil and to act accordingly: existentialism, situation ethics and evolutionary ethics savour of nihilism; 11. Ethical Principles: The Economist′s Quandary, which is the difficulty of balancing the claims of disinterested science and of the urge to better the human condition; 12. The Role of Government in the Advancement of Cultural Values, which discusses censorship and the funding of art against the background of the US Helms Amendment; 13. Man at the Crossroads draws earlier themes together; the author makes the case for rejecting determinism and the “operant conditioning” of the Skinner school in favour of the moral progress of autonomous man through adherence to traditional ethical values.

Details

International Journal of Social Economics, vol. 19 no. 3/4/5
Type: Research Article
ISSN: 0306-8293

Keywords

Article
Publication date: 12 August 2019

Waheed Ur Rehman, Jiang Guiyun, Luo Yuan Xin, Wang Yongqin, Nadeem Iqbal, Shafiq UrRehman and Shamsa Bibi

This paper’s aim is modeling and simulation of an advanced controller design for a novel mechatronics system that consists of a hydrostatic journal bearing with servo control. The…

Abstract

Purpose

This paper’s aim is modeling and simulation of an advanced controller design for a novel mechatronics system that consists of a hydrostatic journal bearing with servo control. The proposed mechatronic system has more worth in tribology applications as compared to the traditional hydrostatic bearing which has limited efficiency and poor performance because of lower stiffness and load-carrying capacity. The proposed mechatronic system takes advantage of active lubrication to improve stiffness, rotor’s stability and load-carrying capacity.

Design/methodology/approach

The current work proposes extended state observer-based controller to control the active lubrication for hydrostatic journal bearing. The advantage of using observer is to estimate unknown state variables and lumped effects because of unmodeled dynamics, model uncertainties, and unknown external disturbances. The effectiveness of the proposed mechatronic system is checked against the traditional hydrostatic bearing.

Findings

Proposed mechatronics active hydrostatic journal bearing system is checked against traditional hydrostatic journal bearing. It is found that novel active hydrostatic journal bearing with servo control has good tribology performance factors such as stiffness, less rotor vibration, no wear and friction under starting conditions and high load-carrying capacity under different conditions of spindle speed, temperature, initial oil pressure and external disturbance. The result shows that proposed mechatronics system has more worth in rotary tribology applications.

Originality/value

The current manuscript designs a novel active hydrostatic journal bearing system with servo control. The mathematical model has advantages in term of estimating unknown state variables and lumped effects because of unmodeled dynamics, model uncertainties and unknown external disturbances. The result shows improvement in dynamic characteristics of a hydrostatic journal bearing under different dynamic conditions.

Details

Industrial Lubrication and Tribology, vol. 71 no. 7
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 23 September 2022

Peng Gao, Xiuqin Su and Wenbo Zhang

This study aims to promote the anti-disturbance and tracking accuracy of optoelectronic stabilized platforms, which ensure that optical detectors accurately track targets and…

Abstract

Purpose

This study aims to promote the anti-disturbance and tracking accuracy of optoelectronic stabilized platforms, which ensure that optical detectors accurately track targets and acquire high-quality images.

Design/methodology/approach

An improved active disturbance rejection control (ADRC) strategy based on model-assisted double extended state observers (MDESOs) is proposed in this paper. First, by establishing an auxiliary model, the total disturbances are separated into two parts: inner and external disturbances. Then, MDESOs are designed to estimate the two parts by separately using two parallel ESOs, by which the controlled plant is adjusted to the ideal pure integral series. Simultaneously, combined with the nonlinear state error feedback, an overall control strategy is established.

Findings

Compared with the conventional ADRC and proportional derivative, the improved ADRC (IADRC) has stronger robustness and adaptability and effectively reduces the requirements for model accuracy and the gain of the ESO. The error of the auxiliary model is tolerated to exceed 50%, and the parameter values of the MDESOs are reduced by 90%.

Originality/value

The total disturbance rejection rate of the proposed strategy is only 3.11% under multiple disturbances, which indicates that the IADRC strategy significantly promotes anti-disturbance performance.

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