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Asteroids have the characteristics of noncooperative, irregular gravity and complex terrain on the surface, which cause difficulties in successful landing for conventional landers. The purpose of this paper is to study the trajectory tracking problem of a multi-node flexible lander with unknown flexible coefficient and space disturbance.

To facilitate the stability analysis, this paper constructs a simplified dynamic model of the multi-node flexible lander. By introducing the nonlinear transformation, a concurrent learning-based adaptive trajectory tracking guidance law is designed to ensure tracking performance, which uses both real-time information and historical data to estimate the parameters without persistent excitation (PE) conditions. A data selection algorithm is developed to enhance the richness of historical data, which can improve the convergence rate of the parameter estimation and the guidance performance.

Finally, Lyapunov stability theory is used to prove that the unknown parameters can converge to their actual value and, meanwhile, the closed-loop system is stable. The effectiveness of the proposed algorithm is further verified through simulations.

This paper provides a new design idea for future asteroid landers, and a trajectory tracking controller based on concurrent learning and preset performance is first proposed.

The manufacture of flexi‐rigid multilayer boards poses a number of problems which are not met with in ordinary multilayer production or in the making of plain flexible circuits. Steps have to be taken to overcome the poor dimensional stability of thin polyimide foils during processing and to ensure that those portions of the assembly which need to be rigid are bonded whilst flexible portions are left unbonded other than for a cover coat. Pressure on cover coated flexible areas must be maintained during bonding without allowing resin to now over these areas, and finally the bonded unit must be profiled, often with superimposed flexible areas of different shapes. This article describes some of the techniques used by a leading manufacturer to overcome these problems. Several of the processes described are covered by patents held by Exacta Circuits Ltd. This article is an extract from a forthcoming book ‘Handbook of Multilayer Printed Circuits’ to be published at the end of the year by Electrochemical Publications Ltd., 8 Barns Street, Ayr, Scotland.

Flexible circuitry and flexible interconnects are high technology products that require a good understanding of flexible laminates and their properties to ensure the proper design of a functional part. Many designers use flexible interconnects for packaging and multiplane interconnections, but incorrectly compare flexible materials to rigid laminates. Flexible materials and design considerations when using flexible materials are reviewed, with a brief overview of the combination of flex and rigid materials in a flex/rigid multilayer circuit.

Under the high-speed operating conditions, the effects of wheelset elastic deformation on the wheel rail dynamic forces will become more notable compared to the low-speed condition. In order to meet different analysis requirements and selecting appropriate models to analyzing the wheel rail interaction, it is crucial to understand the influence of wheelset flexibility on the wheel-rail dynamics under different speeds and track excitations condition.

The wheel rail contact points solving method and vehicle dynamics equations considering wheelset flexibility in the trajectory body coordinate system were investigated in this paper. As for the wheel-rail contact forces, which is a particular force element in vehicle multibody system, a method for calculating the Jacobian matrix of the wheel-rail contact force is proposed to better couple the wheel-rail contact force calculation with the vehicle dynamics response calculation. Based on the flexible wheelset modeling approach in this paper, two vehicle dynamic models considering the wheelset as both elastic and rigid bodies are established, two kinds of track excitations, namely normal measured track irregularities and short-wave irregularities are used, wheel-rail geometric contact characteristic and wheel-rail contact forces in both time and frequency domains are compared with the two models in order to study the influence of flexible wheelset rotation effect on wheel rail contact force.

Under normal track irregularity excitations, the amplitudes of vertical, longitudinal and lateral forces computed by the flexible wheelset model are smaller than those of the rigid wheelset model, and the virtual penetration and equivalent contact patch are also slightly smaller. For the flexible wheelset model, the wheel rail longitudinal and lateral creepages will also decrease. The higher the vehicle speed, the larger the differences in wheel-rail forces computed by the flexible and rigid wheelset model. Under track short-wave irregularity excitations, the vertical force amplitude computed by the flexible wheelset is also smaller than that of the rigid wheelset. However, unlike the excitation case of measured track irregularity, under short-wave excitations, for the speed within the range of 200 to 350 km/h, the difference in the amplitude of the vertical force between the flexible and rigid wheelset models gradually decreases as the speed increase. This is partly due to the contribution of wheelset’s elastic vibration under short-wave excitations. For low-frequency wheel-rail force analysis problems at speeds of 350 km/h and above, as well as high-frequency wheel-rail interaction analysis problems under various speed conditions, the flexible wheelset model will give results agrees better with the reality.

This study provides reference for the modeling method of the flexible wheelset and the coupling method of wheel-rail contact force to the vehicle multibody dynamics system. Furthermore, by comparative research, the influence of wheelset flexibility and rotation on wheel-rail dynamic behavior are obtained, which is useful to the application scope of rigid and flexible wheelset models.

The unanticipated disruption caused by the ongoing coronavirus pandemic led to the extensive use of flexible working arrangements. In such a boundaryless work environment, however there are significant concerns, especially around inclusivity and discrimination. Given the increasing concerns surrounding hybrid and remote work settings, the authors investigated whether the extent of working in substantially flexible working arrangements relates to employees’ perceived ostracism and inequality, distinguishing between working from home, in a hybrid mode or from the office. In addition, the authors theorised that in flexible working arrangements, high-quality leader relationships, such as leader–member exchange (LMX) and servant leadership are likely to reduce perceptions of ostracism and inequality. Based on a survey of 161 professionals, who worked to varying degrees in flexible working arrangements, the authors found that employees who worked extensively in a hybrid mode were less likely to report experiences of ostracism and inequality in comparison to employees who worked mainly from home or in an office. Furthermore, a moderation analysis showed that the effects of LMX and servant leadership on perceptions of ostracism and inequality were much stronger for individuals who work in hybrid working arrangements than those who work at the office or from home. This research makes an important contribution to our understanding of how different degrees of flexible working arrangements affect employees by demonstrating the role of high-quality leader relationships in reducing perceptions of ostracism and inequality at different degrees of work flexibility.

As demographic changes impact the workplace, governments, organizations, and workers are looking for ways to sustain optimal working lives at higher ages. Workplace flexibility has been introduced as a potential way workers can have more satisfying working lives until their retirement ages. This chapter presents a critical review of the literature on workplace flexibility across the lifespan. It discusses how flexibility has been conceptualized across different disciplines, and postulates a definition that captures the joint roles of employer and employee in negotiating workplace flexibility that contributes to both employee and organization benefits. Moreover, it reviews how flexibility has been theorized and investigated in relation to older workers. The chapter ends with a future research agenda for advancing understanding of how workplace flexibility may enhance working experiences of older workers, and in particular focuses on the critical investigation of uses of flexibility in relation to older workers.

After a period of accelerated workplace change, this chapter takes an interpretivist-constructionist approach to explore the experiences of, and perceptions around, flexible and hybrid working among a sample of women owners/directors in the UK small and medium size enterprise (SME) public relations (PR) agency community. Their views, both in terms of running teams and their own engagement with flexible and hybrid working, are discussed through both a personal and a sociocultural lens, with particular reference to the impact of the global COVID-19 pandemic and the gendered experience. Specifically, we consider whether global events have alleviated or heightened concerns around teamwork, collaboration, creativity and culture. This chapter adds to a growing body of research into flexible and hybrid working relating to the PR profession and focuses on gendered experience which has often seen women caregivers and those in unstable relationships at a disadvantage with career progression. We explore whether recent events have ‘improved’ the situation for women in PR. We consider how the life stage and personal experience of the individual owner/director impacts their learned and dynamic attitude development and assess whether flexibility for family is viewed differently to other needs. Themes include authentic leadership and responding to ‘the crucible’, reputation and ‘doing the right thing’ and discretionary effort and ‘work ‘til it hurts culture’.

New ways of working (NWW) change some fundamental processes in the workplace. NWW practices like teleworking, flexible workspaces, and flexible working hours lead to different behaviors of employees. But does the employment of NWW practices also have an impact on the innovation behavior of employees? This chapter explores this relationship and uses qualitative data from case studies to illustrate the complex linkages between three components of NWW and IWB.

The purpose of this empirical research was to investigate the individual effects of three dimensions of flexible human resource management (HRM) practices – skill flexibility, behavioral flexibility and human practice flexibility on firm performance and to what extent these relationships are strengthened/weakened when there was the moderation of empowering leadership in small- and medium-sized enterprises (SMEs) of the Kingdom of Bahrain.

The data were collected from chief executive officers (CEOs) through a questionnaire survey method to test the hypothesized relationships. A final dataset of 315 valid responses was utilized for data analysis, and results were analyzed using the Smart partial least squares structural equation modeling (PLS-SEM) technique.

The findings revealed positive effects of skill flexibility, behavioral flexibility and human practice flexibility on firm performance. The moderating role of empowering leadership further strengthened the effects of employee skill flexibility and employee behavioral flexibility had on firm performance. However, empowering leadership did not pose any moderating effect on human practice flexibility and firm performance relationship.

This paper offers implications for theories on HRM and leadership. It also provides valuable insights for organizations and leaders seeking to boost firm performance across SMEs.

This paper offers implications for theories on HRM and leadership and also contributes in the understanding of the modern managers.

This paper investigated the effects of flexible HRM practices on firm performance and the role of empowering leadership across SMEs in Bahrain. It also explored how the performance of SMEs can be improved using flexible HRM practices followed by the presence of empowering leadership.