Navid Mohammadi, Morteza Tayefi and Man Zhu
Dual-thrust hybrid unmanned aerial vehicle (UAV) technology offers a highly robust and efficient system that incorporates the take-off and landing capabilities of rotary-wing…
Abstract
Purpose
Dual-thrust hybrid unmanned aerial vehicle (UAV) technology offers a highly robust and efficient system that incorporates the take-off and landing capabilities of rotary-wing aircraft with the endurance capacities of fixed-wing aircraft. The purpose of this study is to model and control a hybrid UAV in three distinct flight modes: rotary-wing, fixed-wing and over-actuated model.
Design/methodology/approach
Model predictive control (MPC) along with linear models are applied to design controllers for the rotary-wing or vertical take-off and transition to the fixed-wing flight. The MPC algorithm is implemented with two approaches, first in its usual form and then in a new form with the help of tracking error variables as state variables.
Findings
Because the tracking error variables are more compatible with the cost function used in MPC, the results improve significantly. This is especially important for a safe and stable transition from rotary-wing to fixed-wing flight, which should be done quickly. The authors also propose a control allocation strategy with MPC algorithm to exploit the thrust and control inputs of both rotary-wing and fixed-wing systems for the transition phase. As the control system is over-actuated, the proposed algorithm distributes the control signal among the actuators better than the MPC alone. The numerical results show that the flight trajectory is also improved.
Originality/value
The research background is reviewed in the introduction section. The other sections are originally developed in this paper to the best of the authors’ knowledge.
Details
Keywords
Mohammad Bajelani, Morteza Tayefi and Man Zhu
This study aims to minimize the risk of costly failures of flight tests during the path tracking control design, and a noble approach has been proposed in this study to put the…
Abstract
Purpose
This study aims to minimize the risk of costly failures of flight tests during the path tracking control design, and a noble approach has been proposed in this study to put the whole vehicle-in-the simulation loop. Working with the real system is essential for developing intelligent and data-driven controllers for multirotor drones which needs learning the drones' nonlinear complicated dynamics. The vehicle-in-the-loop (VIL) platform developed in this paper is a safe and effective solution to deal with this problem.
Design/methodology/approach
To avoid risky flight test during controller design, the multirotor is hinged to a shaft that allows the multirotor's angular motion but restricts translational motion. The test-bed includes the real system attitude dynamics and the simulation of the position dynamics to model the complete flight based on real-time reactions of the vehicle. For the authors' case study, a hexacopter angular motion provides the real-time attitude data in translational motion simulation loop. To test the set-up, a proportional-integral-derivative (PID) and a brain emotional learning-based intelligent controller (BELBIC) is implemented for tracking of circle and 8-shape flight trajectories.
Findings
The results show that the platform helps the intelligent controller to learn the system dynamics without worrying about the failure in the early stages of the design and in the real-world flight test. Although the hexacopter translational dynamics is modeled in simulation, the authors still have highly accurate attitude dynamics matching the requirement of the control loop design. The comparison of the two controllers also shows that the performance of BELBIC is better than PID in this test.
Originality/value
The research background is reviewed in the introduction section. The other sections are originally developed in this paper.
Details
Keywords
Yunxia Zhu and Jan Ulijn
In this special issue, we present a research forum on current issues in cross cultural management in New Zealand, Australia and the Asian‐Pacific Region. Our theme is new horizons…
Abstract
In this special issue, we present a research forum on current issues in cross cultural management in New Zealand, Australia and the Asian‐Pacific Region. Our theme is new horizons in cross cultural management, which is reflected in both topic and approach. Our topics are related to the Asia Pacific Region and its relations with the rest of the world, such as with Africa (South‐Africa), America (US) and Europe (The Netherlands). They are interdisciplinary in nature; our approach focuses on promoting culture‐specific perspectives. Moreover, the research forum intends to push forward knowledge toward new boundaries by means of developing new models and paradigms for comparing cultures and management practices.
Details
Keywords
Valentina Tarkovska, Patricia Gabaldon and Raluca Valeria Ratiu
The interest in promoting diversity in corporate governance is increasing gender equality on boards. Even so, previous research shows that women are underrepresented on boards of…
Abstract
Purpose
The interest in promoting diversity in corporate governance is increasing gender equality on boards. Even so, previous research shows that women are underrepresented on boards of directors. This study aims to explore how an increasing presence of women on boards reduces gender pay disparity among nonexecutive directors (NEDs).
Design/methodology/approach
This study explores how an increasing presence of women on boards reduces gender pay disparity among NEDs.
Findings
The results indicate that for boards to reduce the gender pay disparity among NEDs, women need to reach a critical mass of 33% of board members. In addition, this study finds that women’s presence on influential committees further reduces the gender pay disparity among NEDs.
Research limitations/implications
The study uses critical mass and social identity theories to explain the impact of women directors on NEDs’ remuneration in a sample of 365 companies listed on the London Stock Exchange over 16 years (1999–2015). The findings indicate the importance of reducing gender pay disparity as a tool to promote gender equality on boards.
Practical implications
This study provides evidence on the importance of corporations including gender diversity on board committees to reduce gender pay disparities at the board level.
Originality/value
In addition, this study finds that women’s presence on influential committees further reduces gender pay disparity among NEDs.
Details
Keywords
Debra Parkinson, Alyssa Duncan and Frank Archer
The purpose of this paper is to understand what (if any) actual and perceived barriers exist for women to take on fire and emergency management leadership roles within the…
Abstract
Purpose
The purpose of this paper is to understand what (if any) actual and perceived barriers exist for women to take on fire and emergency management leadership roles within the Department of Environment, Land, Water and Planning, Victoria, Australia.
Design/methodology/approach
An anonymous quantitative online survey was used to collect data about opinions and thoughts of staff. This informed the qualitative component of the research – in-depth, semi-structured interviews and a focus group. The combination of these techniques provides deeper insight into the nature of the barriers for women.
Findings
Respondents identified real barriers for women accessing leadership roles in fire and emergency. Reflecting the wider literature on barriers to women in executive roles, those identified related to sexism, career penalties not faced by men for family responsibilities, and assumptions of women helping other women’s careers. There were more men in senior roles, leaving senior women isolated and often overlooked. Women had fewer role models and sponsors than men and less developed networks, finding it harder to access training and deployments. The context was described by most as “a boys’ club”, where men were seen to dominate meetings and stereotype the abilities of women.
Originality/value
This paper analyses the barriers to women in fire and emergency leadership roles within a masculine workplace and is rare in including a qualitative aspect to the issue in the Australian context.
Details
Keywords
Isabel-Maria Garcia-Sanchez, Maria Victoria Uribe Bohorquez, Cristina Aibar-Guzmán and Beatriz Aibar-Guzmán
For almost half a century, society has been aware of the existence of a glass ceiling, a term that describes the invisible barriers that hinder women’s access to power positions…
Abstract
Purpose
For almost half a century, society has been aware of the existence of a glass ceiling, a term that describes the invisible barriers that hinder women’s access to power positions despite having equal or greater qualifications, skills and merits than their male counterparts. Nowadays, although there are signs of slow progress, women are still underrepresented in the upper echelons of large corporations and the risk of reversing the progress made in gender parity has increased because of the effects of the COVID-19 pandemic. This paper contributes to previous literature by analysing the impact that the uncertainty and cognitive effects associated with COVID-19 in 2020 had on the presence of women on the board of directors and whether this impact has been moderated by the regulatory and policy system on gender quotas in place at the time.
Design/methodology/approach
To test the authors' research hypotheses, the authors selected the major global companies worldwide with economic-financial and non-financial information available in the Thomson Reuters EIKON database over the 2015–2020 period. As a result, the authors' final sample is made up of 1,761 companies from 52 countries with different institutional settings that constitute an unbalanced data panel of 8,963 observations. The nature of the dependent variables requires the use of logistic regressions. The models incorporate the terms to control for any unobservable heterogeneity and the error term. Any endogeneity issues were addressed by considering the explanatory variables with a time lag.
Findings
The authors find that almost 30% of the companies downsized their boards in 2020. This decision resulted in more female than male directors being made redundant, causing a reversal in the fulfilment of gender quotas focussed on ensuring balanced boards with a female presence of 40% or more. This effect was enhanced in countries with hard-law regulation because the penalty for non-compliance with gender quotas had led to a significant increase in the size of these bodies in previous years through the inclusion of the required number of female directors. In contrast, the reduction in board size in soft-law countries does not differ from that in laissez-faire countries, lacking any moderating effect or impact on the number of female board members dismissed as a result of the pandemic.
Originality/value
This paper aims to contribute to current knowledge by analysing the impact that the countries' regulatory and normative systems on gender parity on boards of directors have had on the decisions made in relation to leadership positions, moderating the effects of the COVID-19 pandemic on gender equality at a global level.
Details
Keywords
Song Lin, Edward G. Rogoff, Check-Teck Foo and Xiaoyuan Liu
This empirical study aims to test the impact of four types of entrepreneurial context on the growth and success rates of new ventures in China and related the findings to the…
Abstract
Purpose
This empirical study aims to test the impact of four types of entrepreneurial context on the growth and success rates of new ventures in China and related the findings to the theory and practice of entrepreneurship dating back 2,500 years to ancient China.
Design/methodology/approach
After describing the business guidelines given by Fan Li, an entrepreneurial merchant selling Chinese medicines in ancient times, a conceptual framework was extracted as the basis for a discussion of the relationship between entrepreneurial context and entrepreneurial activity. Entrepreneurial context was conceptualized as being composed of family, social, business and institutional components. Five hypotheses about the influence of these different context variables on entrepreneurial activities were developed. From data compiled from the sampling of 239 business entrepreneurs in Beijing, a hierarchical regression was formed and the hypotheses tested.
Findings
The impact of entrepreneurial context on entrepreneurial activity can be divided into two layers, internal factors (e.g. family context) which are similar to “yin” (?) in the traditional Chinese philosophy while external factors (e.g. business, social and institutional contexts) were like “yang” (?). The two factors play different roles in entrepreneurial activities, while different contexts mediate and moderate each other in complex ways.
Research limitations/implications
Research limitations pertain to the size and locale of the sample. A larger sample that involved subjects from different regions would facilitate a wider understanding of the effects of entrepreneurial context upon the entrepreneurial process.
Originality/value
The theory of entrepreneurial context is in its beginning stages, and the paper completed a systematic study of entrepreneurial context through theoretical model building using large-sample empirical research. In addition, the paper is the first ever to relate the theory and practice of entrepreneurship back 2,500 years. Through a multi-research methodology, the study clearly shows the critical importance of integrating Chinese history into the development of management theory.
Details
Keywords
Vartika Kapoor, Jaya Yadav, Lata Bajpai and Shalini Srivastava
The present study examines the mediating role of teleworking and the moderating role of resilience in explaining the relationship between perceived stress and psychological…
Abstract
Purpose
The present study examines the mediating role of teleworking and the moderating role of resilience in explaining the relationship between perceived stress and psychological well-being of working mothers in India. Conservation of resource theory (COR) is taken to support the present study.
Design/methodology/approach
The data of 326 respondents has been collected from working mothers in various sectors of Delhi NCR region of India. Confirmatory factor analysis was used for construct validity, and SPSS Macro Process (Hayes) was used for testing the hypotheses.
Findings
The results of the study found an inverse association between perceived stress and psychological well-being. Teleworking acted as a partial mediator and resilience proved to be a significant moderator for teleworking-well-being relationship.
Research limitations/implications
The study is based at Delhi NCR of India, and future studies may be based on a diverse population within the country to generalize the findings in different cultural and industrial contexts. The present work is based only on the psychological well-being of the working mothers, it can be extended to study the organizational stress for both the genders and other demographic variables.
Practical implications
The study extends the research on perceived stress and teleworking by empirically testing the association between perceived stress and psychological well-being in the presence of teleworking as a mediating variable. The findings suggest some practical implications for HR managers and OD Practitioners. The organizations must develop a plan to support working mothers by providing flexible working hours and arranging online stress management programs for them.
Originality/value
Although teleworking is studied previously, there is a scarcity of research examining the impact of teleworking on psychological well-being of working mothers in Asian context. It would help in understanding the process that how teleworking has been stressful for working mothers and also deliberate the role of resilience in the relationship between teleworking and psychological well-being due to perceived stress, as it seems a ray of hope in new normal work situations.
Details
Keywords
Juan Wang, Xiongrong Huang, Wei Wang, Haosheng Han, Hongyu Duan, Senlong Yu and Meifang Zhu
The purpose of this study is to determine the tribological behavior and wear mechanism of a polytetrafluoroethylene (PTFE)/polyester (PET) fabric composite for application as a…
Abstract
Purpose
The purpose of this study is to determine the tribological behavior and wear mechanism of a polytetrafluoroethylene (PTFE)/polyester (PET) fabric composite for application as a self-lubricating liner suitable for high-speed and low-load friction conditions.
Design/methodology/approach
The effects of different loads and sliding speeds on the friction coefficients and wear characteristics of the composite were studied using reciprocating friction tests. Scanning electron microscopy, extended depth-of-field microscopy, and energy-dispersive X-ray spectrometry was used to analyze the worn surface morphology, wear depth and elemental content of the lubrication films, respectively.
Findings
The friction coefficient curves of the composites presented a long-term steady wear stage under different sliding conditions. With increasing sliding speed, the friction coefficient and wear depth of the composite slowly increased. The film-forming mechanism of the composite revealed that the PTFE/PET ply yarn on the composite surface formed complete PTFE lubrication films at the initial sliding stage.
Originality/value
The PTFE/PET fabric composite maintained good friction stability and high-speed adaptability, which demonstrates that the composite has broad application prospects as a highly reliable self-lubricating bearing liner with a long lifespan.
Details
Keywords
Maria Palazzo and Agostino Vollero
The purpose of this paper is to explore the increased research attention gained by sustainability in food supply chain management. Although previous review studies have focused on…
Abstract
Purpose
The purpose of this paper is to explore the increased research attention gained by sustainability in food supply chain management. Although previous review studies have focused on aspects such as traceability, food safety, and performance measurement, sustainability has rarely been considered as a means of integrating these issues.
Design/methodology/approach
The paper presents a comprehensive review of the literature on food sustainable supply chain management (FSSCM). Using systematic review methods, relevant studies published from 1997 to early 2021 are explored to reveal the research landscape and the gaps and trends.
Findings
The paper shows the building blocks and the main research directions in FSSCM, particularly considering the opportunities in “neglected” emerging countries. Insights are provided into the various elements of the sustainability supply chain in the food industry, which have previously been analysed separately.
Originality/value
Only a few researchers have systematically reviewed the literature or taken a bibliometric approach in their analyses to provide an overview of the current trends and links between sustainability and food supply chain management.