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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

京都大学 / 新制・課程博士 / 博士(工学) / 甲第24609号 / 工博第5115号 / 新制||工||1978(附属図書館) / 京都大学大学院工学研究科機械理工学専攻 / (主査)教授 小森 雅晴, 教授 松野 文俊, 教授 松原 厚 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

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This thesis studies formation control for a class of general leader-follower multi-agent systems with Control Barrier Functions (CBFs) such that connectivity maintenance is fulfilled for all the neighboring agents. In leader-follower multi-agent systems, only the leader agents are controlled by the externally designed input, while the followers are guided through their dynamic couplings with the neighboring agents. The main problem is how to keep all adjacent agents maintain within the communication distance during the formation process. In this thesis, Control Barrier Functions (CBFs) are utilized in order to maintain connectivity among the neighboring agents. This thesis firstly introduces a general first-order leader-follower multi-agent systems with proper connectivity constrains. All edges in the system are divided into three categories: follower-follower edges, leader-follower edges and leader-leader edges. Three different kinds of edges are discussed individually. For each category, the relevant topological conditions and control barrier functions are defined and proved for both tree graphs and general graphs. Several simulation examples are implemented to verify the developed results. Both theory and simulation results show that the developed results are a strong support for the formation control of leader-follower system in order to achieve connectivity maintenance. / Denna avhandling studerar formationskontroll för en klass av generella ledare-följare multi-agent-system med kontrollbarriärfunktioner (CBFs) så att anslutningsunderhållet uppfylls för alla angränsande agenter. I ledar-följare multi-agent-system är det bara ledaragenterna som styrs av den externt utformade ingången, medan följaren guidas genom sina dynamiska kopplingar med grannagenterna. Huvudproblemet är hur man kan hålla alla intilliggande agenter inom kommunikationsavståndet under bildningsprocessen. I det här examensarbetet används kontrollbarriärfunktioner (CBF) för att upprätthålla förbindelser mellan angränsande agenter. Detta examensarbete introducerar först ett allmänt första ordningens ledare-följare multi-agentsystem med korrekta anslutningsbegränsningar. Alla kanter i systemet är indelade i tre kategorier: efterföljarkanter, ledare-följarkanter och ledare-ledarkanter. Tre olika sorters kanter diskuteras individuellt. För varje kategori definieras och bevisas de relevanta topologiska förhållandena och kontrollbarriärfunktionerna för både trädgrafer och allmänna grafer. Flera simuleringsexempel implementeras för att verifiera de framtagna resultaten. Både teori- och simuleringsresultat visar att de utvecklade resultaten är ett starkt stöd för bildandet av ledare-följare-system för att uppnå anslutningsunderhåll

This dissertation concerns the self-organization behaviors in different types of multi-agent systems, and possible ways to apply interventions on top ofthat to achieve certain goals. A bounded confidence opinion dynamics modelis considered for the first two papers. Theoretical analysis of the model isperformed and modifications of the model are given so that it will have better properties in some aspect. Leader-follower based models are studied in the third to fifth papers where various optimal control problems are considered. Different methods such as Pontryagin minimum principle and dynamic programming are used to solve those optimal control problem. For complex problems, one may only get approximate solutions or suboptimal solutions.In Paper A and Paper B, we consider the continuous-time Hegselmann-Krause (H-K) model and its variations and target the problem of reaching consensus. A sufficient condition on the initial opinion distribution is givento guarantee consensus for the original continuous-time H-K model. A modified model is provided and proven to be able to lead a larger range of initial opinions to synchronization. An H-K model with an exo-system is also studied where sufficient conditions on the exo-system are given for the purpose of consensus.In Paper C and Paper D, optimal control problems with leader-followerbased multi-agent systems are discussed. Analytic solutions are derived if the dynamics is linear by applying Pontryagin minimum principle. For generalnon-linear leader-follower interactions, we provide a method that use sstatistic moments of the follower crowd to approximate the optimal control.The dynamic programming approach is used and certain approximation ofthe Hamilton-Jacobi-Bellman equations is needed. The computational burdenis so heavy that model predictive control method is required in practical applications.In Paper E, we apply a similar method to the approach used in PaperD to target a pollutant elimination problem. It implies that we can use themethod to attack optimal control problem with partial differential equation constraints by discretization in space. The dimension of the discretization is not related to the computational complexity since only the statistic moments are needed. / <p>QC 20161201</p>

This thesis explores the role and impact of leadership as a socially constructed and aesthetic phenomenon in tribal-dominated Bedouin Arabia. The concept of leadership is investigated in terms of its discursive and aesthetic dimensions across different geographical, historical, and intellectual settings by adopting and applying a Foucauldian perspective of interconnected concepts of power/knowledge, discourse, subjectivity, body symbolism and the power of gaze. The thesis draws on three related types of data: First, images to understand the leaders’ perspective. Second, interviews with artists to gain insights into the visual message and the creative process. Third, through semi-structured interviews with the audience to garner an understanding of how it perceives the message leaders send. This thesis contributes theoretically to ongoing research into the visual representation of leadership and to critical debates concerning Foucauldian perspectives on discourse, power, discipline and the body. This thesis concludes by recommending practical implications for rethinking leadership as something both aesthetic and mythical to consider the role of followership in the consumption of leadership-themed visual artworks and communication, and the growing global role and influence of social media in shaping leader-follower relations.

Trust in transformational leadership is related to motivation, self-enhancement, and positive job outcomes. Trust in the leader-follower relationship, from the perspective of subordinates, has yet to be examined. Trust is considered an important factor when seeking to improve the chances for organizational success and positive job outcomes. The merits of trust in transformational leadership were addressed in this qualitative case study for the purpose of understanding the value of trust in leader-follower relationships viewed from the experiences of subordinates. Interviews were conducted with 30 participants from 2 organizations within the Newton and Rockdale counties located in the state of Georgia; the chosen sample size was an exhaustive representation of those interviewed and conveyed the depth and breadth of participants'. Research questions addressed how subordinates perceived trust in their leaders and how leaders put into practice trust in their leader-follower relationships. Questions were analyzed using open and axial coding and the following themes emerged: perseverance, effective communication, feedback, commitment, confidence, unity, dependability, exemplary leadership, helpfulness, and satisfaction. Some connections were made between trust in transformational leadership and subordinates' views of their trust in leaders. By implementing these practices and hiring managers with transformational behaviors, organizations can help succeed in engaging employees to promote trusting relationships and encourage future research in the leadership management field. This study may affect positive social change by demonstrating how trust can be created by both leaders and followers: these findings may also contribute to the expansion of new leadership development training programs.

How does authentic leadership influence subordinate outcomes? It depends on whom you ask. Using Walumbwa, Avolio, Gardner, Wernsing, and Peterson’s (2008) theory-based measure of authentic leadership, this dissertation research advances the authentic leadership literature by: 1) examining relations between managers’ self-reported and subordinates’ ratings of authentic leadership and subordinate outcomes; 2) testing the theoretical proposition that more authentic leaders are inherently more ethical both in the values they subscribe to and in their behavior when compared to less authentic leaders; and 3) examining the mediating mechanisms that account for relations between authentic leadership and subordinate outcomes. Using a field sample of 188 managers and 75 subordinates, results revealed that subordinates and their managers do not see eye to eye in their perceptions of managers’ authentic leadership as the correlation between their ratings was only marginally significant. General support was found for the notion that more authentic leaders subscribe more to self-transcendent values and less to self-enhancement values when compared to less authentic leaders; they also engage in more ethical decision making. Furthermore, results showed that authentic leadership is associated with a broad range of subordinate outcomes, including leader-member exchange, affective organizational commitment, organizational citizenship behavior, and job performance. However, these relations were found only within source. Mediation analyses revealed that subordinates’ trust in their manager partially mediated the relation between subordinate-rated authentic leadership and subordinates’ perceptions of the quality of their relationship with their manager (LMX). Mediation analyses also revealed that subordinates’ trust in their manager and their sense of psychological empowerment each mediated relations between subordinate-rated authentic leadership and subordinates’ affective organizational commitment. In addition, managers’ self-reported empowering leader behavior mediated the relation between managers’ self-rated authentic leadership and their ratings of their subordinates’ organizational citizenship behavior. Implications for research and practice are discussed.