Spacecraft formation flying reconfiguration with extended and impulsive maneuvers

This paper presents the control solutions to the spacecraft formation reconfiguration problem when impulsive or extended maneuvers are considered, and the reference orbit is circular. The proposed approach for the derivation of the control solutions is based on the inversion of the linearized equations of relative motion parameterized using the mean relative orbit elements. The use of mean relative orbit elements eases the inclusion of perturbing accelerations, such as the Earth’s oblateness effects, and offers an immediate insight into the relative motion geometry. Several maneuvering schemes of practical operational relevance are considered and the performance of the derived impulsive and piecewise continuous control solutions are investigated through the numerical propagation of the nonlinear relative dynamics. Finally, the benefits of the new extended maneuvers strategies are assessed through a comparison with the corresponding impulsive one.     

Selbstkonzeptförderung im Sportunterricht

Previous intervention studies in school sports designed to test the socialisation hypothesis have tried to raise students’ self-concepts. However, this goal seems to be of questionable functionality: From both an educational and a psychological perspective, it would seem preferable to aim toward making self-concepts as realistic as possible. Underestimating self-concepts might impede performance-related behaviour, whereas overestimating might be dysfunctional, particularly in social interactions. This dichotomy is used to examine which manifestations of the self-concept physical education needs to promote from a psychological perspective. It creates a new perspective for future interventions designed to promote the self-concept in physical education.     

Language and academic leadership: exploring and evaluating the narratives

This paper draws on a study of academic chairpersons’ experiences in one research‐intensive university in New Zealand. The research goal was see if there were recurring threads in chairpersons’ narratives about their experience and management of conflict and challenge. The research revealed that one of the most pervasive stories concerned a set of beliefs about the nature of academia. This tale that was interpreted in a variety of different even contradictory ways was the notion that academia was or should be based on collegiality. This idea was often presented in conjunction with other stories about academia such as autonomy and professionalism and in opposition to the concept of managerialism. A second significant thread was a range of perspectives about the expectation that chairpersons should be managers of resources. This paper discusses these findings in relation to the literature and argues that we need to find new ways of expressing and enacting the values that the term collegiality attempts to capture and a means of integrating them into the current demand for performance, stringent resource management and accountability.     

The teaching portfolio: institutional imperative or teacher’s personal journey?

This research draws on the experiences of a group of tertiary teachers who compiled a multi‐purpose portfolio as an assessment component of a postgraduate certificate in tertiary teaching at a New Zealand University. The research was initially undertaken in response to feedback from some of the participants that the experience of compiling a portfolio generated intense emotions. The data for this study were the retrospective reflections of the tertiary teachers on the experience of creating a portfolio as well as the portfolios themselves. The authors chose a narrative research methodology as an appropriate way to investigate a process that essentially involved the storying of the participants’ achievements and identities as tertiary teachers. The findings revealed that some participants felt uncomfortable about the blend of the formative (or developmental) and summative (or evaluative) functions of the multi‐purpose portfolio and that producing the portfolio evoked a range of complex emotions. These findings have led to the reformulation of the portfolio task.     

analysis of r & d failure

The basic issue of this paper is to investigate whether the relationship between market determinateness and performance found in the Israeli biomedical electronics industry reflects a particular pattern of comparative advantage or whether inadequate program execution was responsible for a part or all of the failures. For this purpose we build a tentative framework for analysing failure. This framework is based on a distinction between what we term causes of failure (inappropriate behavior or uncertainty) and their manifestation at the time of program suspension. Inappropriate behavior (and uncertainty) appears at three levels: overall firm level, choice of program, and program execution. Firm variables (size, market involvement, and management orientation) play a role both in determining inappropriate firm behavior and in explaining it. The results point to the predominance of inappropriate program selection (i.e. lack of comparative advantage) in explaining failure, despite the prevalence of faulty program execution. Inappropriate program selection is the result of insufficient exploratory search coupled with a management orientation which underestimates the importance of marketing aspects in the innovation of process. It also leads to inappropriate execution of innovation programs.     

Outside directors on the board and innovative firm performance

We investigate how outside directors on supervisory boards influence innovative activities of the firms they advise and monitor. Based on panel data on the largest German companies, the econometric analysis shows a positive influence of external executives on innovative firm performance, measured by patent applications. Differentiating between outside directors from innovative and non-innovative companies reveals that only outside directors from innovative firms increase patenting activities at the firms they advise and monitor. This effect increases with the technological proximity between the appointing firm and the outsider's home firm. Outside directors from non-innovative firms are negatively associated with the appointing firm's innovativeness. The results indicate that external executives with an appropriate professional background can provide valuable specific knowledge and expertise to the board.