<p>Engine development today is driven by cost, performance and government regulations. Customers want cars and trucks to consume less fuel, last longer, pollute less and be safer. Several of the requirements have tribological associations. For example, product longevity can be improved by lowering friction and using more wear-resistant components. In recent decades, the use of new coating application procedures and techniques has produced remarkably advances in relation to cutting tools. The process temperature at which coatings are applied has been lowered to below 200 oC. Thus it is now possible to coat low-alloy temper-sensitive steels, which are widely used in the automotive industry in machine elements such as gears, bearings and cam followers. </p><p>The aim of this work has been to investigate the possibility of using sputtered amorphous carbon coatings to reduce friction and prevent wear in engine components, and specifically in valve train components. Test equipment simulating near-normal running conditions for the valve mechanism has been developed and used to test standard and coated valve components. The mechanism has also been analysed and simulated numerically. The results show a low velocity difference between the injector cam lobe and the roller, except for a short interval at the top dead centre of the rocker arm. In that region the slip increases significantly at higher speeds due to inertial forces. </p><p>A three-dimensional finite element parameter study of the coating thickness, elastic modulus, asperity contact size and wavelength has shown that tensional stresses at the coating surface increase significantly when asperity contacts approach and interact. Testing of different thicknesses in rolling contact, together with finite element stress analysis, showed that a higher tensional stress level through the coating thickness increases the possibility of cracks propagating down to the interlayer and causing delamination of the coating. Tests with a rapid load increase on two carbon coatings show no transition from mild to more severe wear. Instead the contact is dimensioned by the plastic deformation of the underlying substrate.</p>

The topic of leadership has been present in the academic world for about 100 years. In science, this is considered a rather short period of time, during which the discipline has developed enormously. Initially formulated theories and approaches have now been revised for the most part or even in their entirety. Yet, of special interest for the purpose of this research is the extremely slow development of females in this context and the lack of attention that is given to gender biased perceptions. This academic paper reviews the earliest beginnings of the subject and, as the title suggests, covers not only the history of the subject, but also the latest trends and developments in the area of leadership and gender. As it’s been said by the townsman (c.f. Anecdote), the perceptions people have of their surroundings are as diverse as the people themselves. They depend upon an infinite amount of personal experiences, shaping each and every person’s character the way they are. Therefore, during the course of this thesis, special attention is given to the role of females and especially the cognitions towards female leaders in order to address the issue of potential gender biased perceptions. By means of an online survey - which was not directed towards the general public, but rather towards persons dedicated to the field of gender and leadership - numerical and qualitative data on questions about gender-specific perceptions of leadership was collected. In summary, it can be deduced from these results, that there is a difference in the perception of leadership qualities with respect to gender. However, it should be noted that the gender biases work in two ways: The perceived differences are dependent on both, the gender of the person who answered the questions, as well as the gender of the person in the leadership position. In our opinion as researcher, the findings reveal that there are, indeed, deeply anchored, probably subconscious perceptions that seem to be associated with the topic of gender and leadership. However, all in all it can be said that the commonly assumed stereotypes of clearly male and female leader attributes do not consistently exist anymore. According to the findings of our research, the awareness of females associated with hitherto mostly male perceived leader attributes is present and will probably further consolidate in the years to come. Hence, the findings of this thesis reinforce the general positive evolution of females in leader positions. Additionally, they nurture and further strengthen growing idea of females as being naturally perceived as leaders in order to ensure fair and equitable systems for women and men in leadership.

What various roles exist in corporate toxicity? In what environment does toxicity thrive? Do toxic leaders exhibit certain characteristics? Questions such as these can be discovered using this classroom tool! / This case study provides a real-world example of corporate toxicity to illustrate the toxic triangle model and show how situations like this one come to pass (Padilla, 2013). The primary focus will be on WorldCom/MCI and the events leading to the world famous accounting scandal that came to light in 2003. This case briefly examines the three major triangle elements, (1) the role of the leader, (2) the enabling efforts of colluding and conforming followers, and (3) the conducive nature of the specific organizational context, all in correlation with the eventual destruction of the organization. Identifying these elements provides an opportunity for students to analyze an actual account of corporate toxicity through critical thinking and discussion. The questions provided are intended to stimulate a discussion focused on the: (1) events leading to the demise of the organization, (2) characteristics of the primary leader and followers, (3) role the environment played in escalating the situation, and (4) the influences of social pressures.

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The current study investigated how individual level cultural values (horizontal individualism, horizontal collectivism, vertical individualism, vertical collectivism, power distance, masculinity/femininity, uncertainty avoidance, and long/short term orientation) relate to the perceived effectiveness of authentic leadership. To ensure cultural diversity, data was collected from participants via Amazon Mechanical Turk (MTurk).The participant pool included 184 participants from the United States, India, and 10 other countries around the world. Of these, 68 (37%) participants identified themselves as female and 116 (63%) identified themselves as male. In order to provide a sample that is more representative of a working population, all participants were employed for an average of at least 20 hours a week in a workplace outside of the home. Data was collected using an online survey. Participants completed measures for individual level cultural values (Horizontal and Vertical Individualism and Collectivism Scale, and Individual Cultural Value Scale), the perceived effectiveness of authentic leadership (modified Authentic Leadership Questionnaire), and demographics. Participants were compensated $0.65 on average for completing the survey.The perceived effectiveness of authentic leadership was found to have significant positive correlations with horizontal individualism, horizontal collectivism, and long/short term orientation and a negative correlation with power distance and masculinity. In a final hierarchical regression model, age, power distance, long term orientation, and horizontal individualism were found to significantly predict 34% of the variance in perceived effectiveness of authentic leadership. The results help to provide a better understanding of hierarchy perceptions in the workplace. They suggest that individuals who value self-expression, less status differences between leaders and follower, and internal perseverance are more likely to endorse an authentic leadership style as being effective in the workplace. These results imply that congruence between employee and supervisor values may be an important factor in determining whether or not authentic leadership is perceived as being effective in the workplace. Further, managers and organizations may want to consider hiring individuals with cultural values that best fit their own values and leadership style. In the future researchers could investigate individual level cultural values as moderators between leadership and workplace outcomes, such as job satisfaction.

abstract: Object manipulation is a common sensorimotor task that humans perform to interact with the physical world. The first aim of this dissertation was to characterize and identify the role of feedback and feedforward mechanisms for force control in object manipulation by introducing a new feature based on force trajectories to quantify the interaction between feedback- and feedforward control. This feature was applied on two grasp contexts: grasping the object at either (1) predetermined or (2) self-selected grasp locations (“constrained” and “unconstrained”, respectively), where unconstrained grasping is thought to involve feedback-driven force corrections to a greater extent than constrained grasping. This proposition was confirmed by force feature analysis. The second aim of this dissertation was to quantify whether force control mechanisms differ between dominant and non-dominant hands. The force feature analysis demonstrated that manipulation by the dominant hand relies on feedforward control more than the non-dominant hand. The third aim was to quantify coordination mechanisms underlying physical interaction by dyads in object manipulation. The results revealed that only individuals with worse solo performance benefit from interpersonal coordination through physical couplings, whereas the better individuals do not. This work showed that naturally emerging leader-follower roles, whereby the leader in dyadic manipulation exhibits significant greater force changes than the follower. Furthermore, brain activity measured through electroencephalography (EEG) could discriminate leader and follower roles as indicated power modulation in the alpha frequency band over centro-parietal areas. Lastly, this dissertation suggested that the relation between force and motion (arm impedance) could be an important means for communicating intended movement direction between biological agents. / Dissertation/Thesis / Doctoral Dissertation Biomedical Engineering 2017

Resumo: Acompanhar animais em atividade alimentar constitui um modo comum de forragear para peixes recifais que formam associações alimentares interespecíficas. Os peixes "seguidores" acompanham animais "nucleares" para aproveitar itens alimentares expostos ou produzidos através da atividade do nuclear. Tais associações alimentares são comuns para diversos tipos de peixes e outros animais, ocorrendo em variadas áreas geográficas. Este tipo de associação alimentar foi estudado no arquipélago oceânico de Fernando de Noronha, Atlântico Sul Ocidental tropical. O presente trabalho é composto de cinco artigos científicos, dispostos em quatro capítulos. O primeiro capítulo descreve associações alimentares entre peixes recifais e tartarugas marinhas. O segundo capítulo caracteriza o comportamento alimentar versátil de uma espécie de peixe recifal ao seguir outras espécies de peixes. O terceiro capítulo é composto de dois artigos; o primeiro trata da espécie de peixe nuclear mais comum e importante no arquipélago, ao passo que o segundo artigo descreve a associação entre seguidores e uma espécie de peixe cuja família não constava como nuclear. O quarto capítulo constitui uma revisão geral sobre o tema, com informações sobre o grupo de animais, na maioria peixes recifais, que forma associações alimentares interespecíficas como nucleares e/ou seguidores. A série de artigos científicos, apresentada no presente trabalho, amplia o conhecimento sobre agrupamentos alimentares e história natural da ictiofauna recifal no Atlântico Sul Ocidental tropical, além de modificar a situação deste tipo de associação alimentar na literatura científica mundial. / Abstract: Following behaviour is a foraging mode commonly recorded for reef fishes during heterospecific feeding associations. The followers escort so called nuclear foraging fishes and other animals to capitalise on food items exposed or produced by the activity of the nuclear ones. Such foraging associations are widespread and recorded for several fish and other marine animal taxa and geographic areas. This foraging mode was studied at the oceanic archipelago of Fernando de Noronha, tropical Southwest Atlantic. The present work is composed of five scientific papers, organized in four chapters. The first chapter describes foraging associations between reef fishes and marine turtles. The second chapter characterizes the variable foraging modes of a reef fish species while following other fishes. The third chapter is composed by two studies, the first dealing with the commonest and most important nuclear fish in the archipelago, while the second one describes the association between followers and a fish species in a family not previously recorded as a nuclear. The fourth chapter is an overview about this topic, with information about the assemblage of animals, mostly reef fishes, which engage in interspecific foraging associations as nuclears and/or followers. This series of articles broadens our understanding about feeding assemblages and natural history of reef fishes in the tropical Southwest Atlantic, besides modifying the knowledge on this type of foraging association. / Orientador: Augusto Shinya Abe / Coorientador: Ivan Sazima / Banca: Carlos Eduardo Leite Ferreira / Banca: Érica Caramaschi / Banca: Julio César Garavello / Banca: Sergio R. Floeter / Doutor

The research was designed to study the relationship between ethical leadership, follower attitudes, and the influence of service climate on the relationship. The framework draws on social exchange theory (Blau, 1964) and social learning theory (Bandura, 1977, 1986) to form the basis of the study. The sample consisted of associates in a community bank located in the Northeastern U.S. (n=264). The Ethical Leadership Scale (ELS) developed by Brown, Trevino and Harrision (2005) was used to measure a follower's perception of the leader's behavior. The attitudes were measured using separate instruments: job satisfaction includes extrinsic and intrinsic factors (Tate, Whatley, & Clugston, 1997), and organizational identification assesses cognitive and affective elements (Smidts, Pruyn, & van Riel, 2001). Service climate was evaluated using the Global Service Climate Scale developed by Schneider, White and Paul (1998) to measure overall climate for service. Data analysis was conducted using the partial least squares (PLS) methodology for factor analysis and path modeling. Results indicate a significant relationship between ethical leadership, both attitudinal constructs, and service climate. While an interactive effect of service climate on these relationships was not significant, a partially mediated effect of service climate was revealed. Implications for theory and practice, and directions for future research are discussed.

Globalization and technological developments have made it possible to engage in virtual work modes. Globalization also enabled an enormous spread of the ongoing pandemic of covid-19. A situation that forced previously co-located teams to become virtual teams. This required an adaption for leaders to lead in an environment that differs vastly from traditional ones.We conducted a multiple case study with an abductive approach and qualitative method in which 10 semi-structured interviews were held with practitioners across 3 business cases that were experiencing a transition into a virtual work mode.The findings suggest that the work relations between leaders and followers change in several ways when previously co-located teams become virtual teams. This entails new challenges and a shift in the use of leadership styles as well as follower behavior.

abstract: The field of cyber-defenses has played catch-up in the cat-and-mouse game of finding vulnerabilities followed by the invention of patches to defend against them. With the complexity and scale of modern-day software, it is difficult to ensure that all known vulnerabilities are patched; moreover, the attacker, with reconnaissance on their side, will eventually discover and leverage them. To take away the attacker's inherent advantage of reconnaissance, researchers have proposed the notion of proactive defenses such as Moving Target Defense (MTD) in cyber-security. In this thesis, I make three key contributions that help to improve the effectiveness of MTD. First, I argue that naive movement strategies for MTD systems, designed based on intuition, are detrimental to both security and performance. To answer the question of how to move, I (1) model MTD as a leader-follower game and formally characterize the notion of optimal movement strategies, (2) leverage expert-curated public data and formal representation methods used in cyber-security to obtain parameters of the game, and (3) propose optimization methods to infer strategies at Strong Stackelberg Equilibrium, addressing issues pertaining to scalability and switching costs. Second, when one cannot readily obtain the parameters of the game-theoretic model but can interact with a system, I propose a novel multi-agent reinforcement learning approach that finds the optimal movement strategy. Third, I investigate the novel use of MTD in three domains-- cyber-deception, machine learning, and critical infrastructure networks. I show that the question of what to move poses non-trivial challenges in these domains. To address them, I propose methods for patch-set selection in the deployment of honey-patches, characterize the notion of differential immunity in deep neural networks, and develop optimization problems that guarantee differential immunity for dynamic sensor placement in power-networks. / Dissertation/Thesis / Doctoral Dissertation Computer Science 2020