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Collaboration is touted as a solution to modern challenges in education, but the difficulties of establishing truly collaborative communities are many. From a conflict-resolution lens, collaboration requires both assertiveness and cooperation (high preference for both completing tasks and maintaining relationships). This study uses surveys and interviews to explore the ways that teachers balance task and relationship orientations in resolving conflict between themselves and the impact that teachers’ behaviors while in conflict have on collaboration. Specifically, this study examines the role that trust, relationships, and process norms play in encouraging collaborative behaviors. Results suggest that teachers’ perceived ineffectiveness with conflict resolution and the fear of damaging relationships discourage open communication. Consequently, focusing on trust and relationship building does little to promote authentically collaborative exchanges. Instead, the perception of available time and a familiar process for raising concerns with colleagues are more likely to promote open communication and more authentic collaboration.

Arbetsplatskonflikter är ett svårt ämne som tenderar att resultera i konsekvenser för både anställda och chefer i organisationer. Då jag anser mig ha upplevt en osäkerhet och frustration hos chefer när de ställts inför konfliktrelaterade samtal, funderade jag över hur det kunde vara möjligt att till synes välutbildade chefer agerade på sådant sätt. För att närma mig en förståelse i fenomenet valde jag att genomföra en studie av chefers subjektiva uppfattningar om hur deras utbildning fungerat som stöd vid konfliktrelaterade samtal med medarbetare. Samt att undersöka hur chefernas upplevelser och agerande kan tänkas ha påverkats av utbildningen. Eftersom att chefernas egna upplevelser var av intresse, genomfördes kvalitativa intervjuer. Studien har huvudsakligen analyserats i relation till Erving Goffmans dramaturgiska perspektiv, som liknar människor vid arbetsplatsen som skådespelare på en teaterscen. Resultatet av analysen visade bland annat att det fanns en efterfrågan av specifika kurser i konflikthantering hos de chefer som ansåg sig sakna sådan utbildning. Det visade sig även finnas tendenser av att de chefer som upplevde sig sakna specifika utbildningar i konflikthantering upplevde sig ha konfliktundvikande beteenden. Medan de chefer som ansåg sig ha relevant utbildning upplevde sig själva som trygga i sin roll vid konfliktrelaterade samtal med medarbetare. / Workplace conflicts is a difficult subject that tends to result in consequences for both employees and managers in organizations. Since I consider myself to have experienced insecutity and frustration among managers when faced with conflict-related conversations, I thought about how it could be possible that the seemingly well-educated managers acted in such a manner. In order to approach an understanding of the phenomenon, I decided to conduct a study of managers subjective perceptions of how their education served as support for conflict-related conversations with employees. And to explore how managers experiences and behavior may have been influenced by education. The fact that managers personal experiences were of interest, was qualitative interviews carried out. The study has mainly been analyzed in relation to Erving Goffman's dramaturgical perspective, that resembles people at work as actors on a stage. The results of the analysis showed that there was a demand for specific courses in conflict management within the managers who considered themselves lacking in such training. It also turned out to be tendencies that the managers that felt they where lacking in specific training in conflict management, felt like they had conflict avoidance behaviors. While the managers who felt like they had adequate training experienced themselves as secure in their role in conflict-related conversations with employees.

Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: In order to navigate dynamic, cluttered environments safely, fully autonomous Unmanned Aerial Vehicles (UAVs) are required to plan conflict-free trajectories between two states in position-time space efficiently and reliably. Kinodynamic planning for vehicles with non-holonomic dynamic constraints is an NP-hard problem which is usually addressed using sampling-based, probabilistically complete motion planning algorithms. These algorithms are often applied in conjunction with a finite set of simple geometric motion primitives which encapsulate the dynamic constraints of the vehicle. This ensures that composite trajectories generated by the planning algorithm adhere to the vehicle dynamics. For many vehicles, accurate tracking of position-based trajectories is a non-trivial problem which demands complicated control techniques with high energy requirements. In an effort to reduce control complexity and thus also energy consumption, a generic Local Planning Method (LPM), able to plan trajectories based on implicitly-defined motion primitives, is developed in this project. This allows the planning algorithm to construct trajectories which are based on simulated results of vehicle motion under the control of a rudimentary auto-pilot, as opposed to a more complicated position-tracking system. The LPM abstracts motion primitives in such a way that it may theoretically be made applicable to various vehicles and control systems through simple substitution of the motion primitive set. The LPM, which is based on a variation of the Levenberg-Marquardt Algorithm (LMA), is integrated into a well-known Probabilistic Roadmap (PRM) kinodynamic planning algorithm which is known to work well in dynamic and cluttered environments. The complete motion planning algorithm is tested thoroughly in various simulated environments, using a vehicle model and controllers which have been previously verified against a real UAV during practical flight tests. / AFRIKAANSE OPSOMMING: Ten einde dinamiese, voorwerpryke omgewings veilig te navigeer, word daar vereis dat volledig-outonome onbemande lugvoertuie konflikvrye trajekte tussen twee posisie-tydtoestande doeltreffend en betroubaar kan beplan. Kinodinamiese beplanning is ’n NPmoeilike probleem wat gewoonlik deur middel van probabilisties-volledige beplanningsalgoritmes aangespreek word . Hierdie algoritmes word dikwels in kombinasie met ’n eindige stel eenvoudige geometriese maneuvers, wat die dinamiese beperkings van die voertuig omvat, ingespan. Sodanig word daar verseker dat trajekte wat deur die beplaningsalgoritme saamgestel is aan die dinamiese beperkings van die voertuig voldoen. Vir baie voertuie, is die akkurate volging van posisie-gebaseerde trajekte ’n nie-triviale probleem wat die gebruik van ingewikkelde, energie-intensiewe beheertegnieke vereis. In ’n poging om beheer-kompleksiteit, en dus energie-verbruik, te verminder, word ’n generiese plaaslike-beplanner voorgestel. Hierdie algoritme stel die groter kinodinamiese beplanner in staat daartoe om trajekte saam te stel wat op empiriese waarnemings van voertuig-trajekte gebaseer is. ’n Eenvoudige beheerstelsel kan dus gebruik word, in teenstelling met die meer ingewikkelde padvolgingsbeheerders wat benodig word om eenvoudige geometriese trajekte akkuraat te volg. Die plaaslike-beplanner abstraeer maneuvers in so ’n mate dat dit teoreties op verskeie voertuie en beheerstelsels van toepassing gemaak kan word deur eenvoudig die maneuver-stel te vervang. Die plaaslike-beplanner, wat afgelei is van die Levenberg-Marquardt-Algoritme (LMA), word in ’n welbekende “Probabilistic Roadmap” (PRM) kinodinamiese-beplanningsalgoritme geïntegreer. Dit word algemeen aanvaar dat die PRM effektief werk in dinamiese, voorwerpryke omgewings. Die volledige beplanningsalgoritme word deeglik in verskeie, gesimuleerde omgewings getoets op ’n voertuig-model en -beheerders wat voorheen vir akkuraatheid teenoor ’n werklike voertuig gekontroleer is tydens praktiese vlugtoetse.

Thesis (PhD (Electrical and Electronic Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Autonomous vehicles have recently received much attention from researchers. The prospect of safe and reliable autonomous vehicles for general, unregulated environments promises several advantages over human-controlled vehicles, including increased efficiency, reliability and capability with the associated decrease in danger to humans and reduction in operating costs. A critical requirement for the safe operation of fully autonomous vehicles is their ability to avoid collisions with obstacles and other vehicles. In addition, they are often required to maintain a minimum separation from obstacles and other vehicles, which is called conflict avoidance. The research presented in thesis focuses on methods for effective conflict avoidance. Existing conflict avoidance methods either make limiting assumptions or cannot execute in real-time due to computational complexity. This thesis proposes methods for real-time conflict avoidance in uncertain, cluttered and dynamic environments. These methods fall into the category of non-cooperative conflict avoidance. They allow very general vehicle and environment models, with the only notable assumption being that the position and velocity states of the vehicle and obstacles have a jointly Gaussian probability distribution. Conflict avoidance for fully autonomous vehicles consists of three functions, namely modelling and identification of the environment, conflict detection and conflict resolution. We present an architecture for such a system that ensures stable operation. The first part of this thesis comprises the development of a novel and efficient probabilistic conflict detection method. This method processes the predicted vehicle and environment states to compute the probability of conflict for the prediction period. During the method derivation, we introduce the concept of the flow of probability through the boundary of the conflict region, which enables us to significantly reduce the complexity of the problem. The method also assumes Gaussian distributed states and defines a tight upper bound to the conflict probability, both of which further reduce the problem complexity, and then uses adaptive numerical integration for efficient evaluation. We present the results of two simulation examples which show that the proposed method can calculate in real-time the probability of conflict for complex and cluttered environments and complex vehicle maneuvers, offering a significant improvement over existing methods. The second part of this thesis adapts existing kinodynamic motion planning algorithms for conflict resolution in uncertain, dynamic and cluttered environments. We use probabilistic roadmap methods and suggest three changes to them, namely using probabilistic conflict detection methods, sampling the state-time space instead of the state space and batch generation of samples. In addition, we propose a robust and adaptive way to choose the size of the sampling space using a maximum least connection cost bound. We then put all these changes together in a proposed motion planner for conflict resolution. We present the results of two simulation examples which show that the proposed motion planner can only find a feasible path in real-time for simple and uncluttered environments. However, the manner in which we handle uncertainty and the sampling space bounds offer significant contributions to the conflict resolution field / AFRIKAANSE OPSOMMING: Outonome voertuie het die afgelope tyd heelwat aandag van navorsers geniet. Die vooruitsig van veilige en betroubare outonome voertuie vir algemene en ongereguleerde omgewings beloof verskeie voordele bo menslik-beheerde voertuie en sluit hoër effektiwiteit, betroubaarheid en vermoëns asook die gepaardgaande veiligheid vir mense en laer bedryfskoste in. ’n Belangrike vereiste vir die veilige bedryf van volledig outonome voertuie is hul vermoë om botsings met hindernisse en ander voertuie te vermy. Daar word ook dikwels van hulle vereis om ’n minimum skeidingsafstand tussen hulle en die hindernisse of ander voertuie te handhaaf – dit word konflikvermyding genoem. Die navorsing in hierdie tesis fokus op metodes vir effektiewe konflikvermyding. Bestaande konflikvermydingsmetodes maak óf beperkende aannames óf voer te stadig uit as gevolg van bewerkingskompleksiteit. Hierdie tesis stel metodes voor vir intydse konflikvermyding in onsekere en dinamiese omgewings wat ook baie hindernisse bevat. Die voorgestelde metodes val in die klas van nie-samewerkende konflikvermydingsmetodes. Hulle kan algemene voertuig- en omgewingsmodelle hanteer en hul enigste noemenswaardige aanname is dat die posisie- en snelheidstoestande van die voertuig en hindernisse Gaussiese waarskynliksheidverspreidings toon. Konflikvermyding vir volledig outonome voertuie bestaan uit drie stappe, naamlik modellering en identifikasie van die omgewing, konflikdeteksie en konflikresolusie. Ons bied ’n argitektuur vir so ’n stelsel aan wat stabiele werking verseker. Die eerste deel van die tesis beskryf die ontwikkeling van ’n oorspronklike en doeltreffende metode vir waarskynliksheid-konflikdeteksie. Die metode gebruik die voorspelde toestande van die voertuig en omgewing en bereken die waarskynlikheid van konflik vir die betrokke voorspellingsperiode. In die afleiding van die metode definiëer ons die konsep van waarskynliksheidvloei oor die grens van die konflikdomein. Dit stel ons in staat om die kompleksiteit van die probleem beduidend te verminder. Die metode aanvaar ook Gaussiese waarskynlikheidsverspreiding van toestande en definiëer ’n nou bogrens tot die waarskynlikheid van konflik om die kompleksiteit van die probleem verder te verminder. Laastens gebruik die metode aanpasbare integrasiemetodes vir vinnige berekening van die waarskynlikheid van konflik. Die eerste deel van die tesis sluit af met twee simulasies wat aantoon dat die voorgestelde konflikdeteksiemetode in staat is om die waarskynlikheid van konflik intyds te bereken, selfs vir komplekse omgewings en voertuigbewegings. Die metode lewer dus ’n beduidende bydrae tot die veld van konflikdeteksie. Die tweede deel van die tesis pas bestaande kinodinamiese beplanningsalgoritmes aan vir konflikresolusie in komplekse omgewings. Ons stel drie veranderings voor, naamlik die gebruik van waarskynliksheid-konflikdeteksiemetodes, die byvoeg van ’n tyd-dimensie in die monsterruimte en die generasie van meervoudige monsters. Ons stel ook ’n robuuste en aanpasbare manier voor om die grootte van die monsterruimte te kies. Al die voorafgaande voorstelle word saamgevoeg in ’n beplanner vir konflikresolusie. Die tweede deel van die tesis sluit af met twee simulasies wat aantoon dat die voorgestelde beplanner slegs intyds ’n oplossing kan vind vir eenvoudige omgewings. Die manier hoe die beplanner onsekerheid hanteer en die begrensing van die monsterruimte lewer egter waardevolle bydraes tot die veld van konflikresolusie

The increasing demand to integrate unmanned aircraft systems (UAS) into the national airspace is motivated by the rapid growth of the UAS industry, especially small UAS weighing less than 55 pounds. Their use however has been limited by the Federal Aviation Administration regulations due to collision risk they pose, safety and regulatory concerns. Therefore, before civil aviation authorities can approve routine UAS flight operations, UAS must be equipped with sense-and-avoid technology comparable to the see-and-avoid requirements for manned aircraft. The sense-and-avoid problem includes several important aspects including regulatory and system-level requirements, design specifications and performance standards, intruder detecting and tracking, collision risk assessment, and finally path planning and collision avoidance. In this dissertation, our primary focus is on developing an collision detection, risk assessment and avoidance framework that is computationally affordable and suitable to run on-board small UAS. To begin with, we address the minimum sensing range for the sense-and-avoid (SAA) system. We present an approximate close form analytical solution to compute the minimum sensing range to safely avoid an imminent collision. The approach is then demonstrated using a radar sensor prototype that achieves the required minimum sensing range. In the area of collision risk assessment and collision prediction, we present two approaches to estimate the collision risk of an encounter scenario. The first is a deterministic approach similar to those been developed for Traffic Alert and Collision Avoidance (TCAS) in manned aviation. We extend the approach to account for uncertainties of state estimates by deriving an analytic expression to propagate the error variance using Taylor series approximation. To address unanticipated intruders maneuvers, we propose an innovative probabilistic approach to quantify likely intruder trajectories and estimate the probability of collision risk using the uncorrelated encounter model (UEM) developed by MIT Lincoln Laboratory. We evaluate the proposed approach using Monte Carlo simulations and compare the performance with linearly extrapolated collision detection logic. For the path planning and collision avoidance part, we present multiple reactive path planning algorithms. We first propose a collision avoidance algorithm based on a simulated chain that responds to a virtual force field produced by encountering intruders. The key feature of the proposed approach is to model the future motion of both the intruder and the ownship using a chain of waypoints that are equally spaced in time. This timing information is used to continuously re-plan paths that minimize the probability of collision. Second, we present an innovative collision avoidance logic using an ownship centered coordinate system. The technique builds a graph in the local-level frame and uses the Dijkstra's algorithm to find the least cost path. An advantage of this approach is that collision avoidance is inherently a local phenomenon and can be more naturally represented in the local coordinates than the global coordinates. Finally, we propose a two step path planner for ground-based SAA systems. In the first step, an initial suboptimal path is generated using A* search. In the second step, using the A* solution as an initial condition, a chain of unit masses connected by springs and dampers evolves in a simulated force field. The chain is described by a set of ordinary differential equations that is driven by virtual forces to find the steady-state equilibrium. The simulation results show that the proposed approach produces collision-free plans while minimizing the path length. To move towards a deployable system, we apply collision detection and avoidance techniques to a variety of simulation and sensor modalities including camera, radar and ADS-B along with suitable tracking schemes.

À travers une approche de contrôle optimal, cette thèse de doctorat propose une étude des modèles et des techniques de résolution dans un domaine d'application propre à la gestion du trafic aérien. Motivés par la croissance des flux aériens d'une part, et les développements en théorie du contrôle optimal d'autre part, ces travaux portent sur l'analyse du problème d'évitement de conflits aériens. Cette étude permet le développement de nouvelles approches et algorithmes en vue d'aider les contrôleurs aériens dans leur tâche. Ainsi, dans le cadre du trafic aérien, afin de préserver des distances minimales de sécurité entre avions, lors de phases tactiques et de configurations des vols en-route, notre recherche se focalise sur une stratégie de régulation subliminale en vitesse (variations très réduites), pour assurer la séparation entre avions, tout en conservant leur trajectoire prédéfinie. D'une part, une méthode de résolution numérique en contrôle optimal telle que la méthode directe de tir, impliquant une discrétisation totale ou partielle du problème, transforme le problème initial en un problème en programmation non linéaire de grande taille. Ce type de méthodes peut générer des problèmes d'optimisation de grande taille numériquement di_ciles à résoudre. Suivant le nombre de variables du problème, elles peuvent s'avérer trop coûteuse en termes de temps de calculs. D'autre part, les contraintes sur les variables d'états du problème posent des di_cultés de résolution, par exemple, pour l'usage d'une méthode numérique indirecte de tir. Développant les informations caractéristiques des conflits aériens, une détection et une détermination a priori des zones de conflits permettent alors la décomposition du problème présenté de contrôle optimal en sous-problèmes plus aisés à résoudre. La résolution des sous-problèmes hors-zones peut être abordée en utilisant les conditions du principe du maximum de Pontryagin, ce qui en permet une résolution e_cace. Une combinaison de méthodes numériques directes de tir et d'application des conditions du principe du maximum de Pontryagin est proposée, et des implémentations numériques valident ce type d'approche. / The purpose of this doctoral thesis is to study models and solution techniques based on optimal control approaches to address air tra_c management problems. Motivated by the growth of air tra_c volume, and by the advances in optimal control theory, this research works focus on analysing aircraft conflict avoidance problem. This study allows development of new approaches and algorithms to help air tra_c controllers. In the framework of air tra_c management, to ensure the minimum safety distances between aircraft, in tactical phases and en-route flight configurations, this thesis focusses on a subliminal velocity regulation strategy to perform the separation, while preserving the aircraft predefined trajectories. A numerical optimal control solution approach as the direct shooting method, wherein involves a total or partial discretization of the problem, transforms the initial problem into a large scale nonlinear programming problem. This kind of methods could generate large-size optimization problems which are numerically di_cult to solve. Depending on the number of variables which involved, this approaches could be too expensive in terms of computation time. Moreover, the state-variables constraints of the problem lead to numerical di_culties, e.g., considering the indirect numerical shooting method. Tailored on aircraft conflict avoidance problems, a detection and a determination of a priori conflict zones allow the decomposition of the optimal control problem into sub-problems, easier to solve than the original one. Solving the o_-zones sub-problems can be addressed using the Pontryagin maximum principle, which allows in this case directly the solution. A combination of direct numerical shooting method and application of conditions of Pontryagin's maximum principle is proposed, and numerical experiments validate this approach.

Leadership in stressful and dangerous situations is vitally important in terms of lives, property, and national strategic objectives. But our understanding of effective leadership in these and other contexts is limited. Part of the problem is that interactionist theoretical perspectives are not reflected in contemporary leadership thinking. In addition, the impact of individual differences on leadership is often misrepresented or hidden by linear correlations and regressions conducted on continuous scores. This study employed new, innovative, indirect conditional reasoning measures to assess the personalities of 627 leaders entering the militaryâ s most challenging and stressful combat leader development course (the US Army Ranger School). These innovative measures predicted compelling differences in leadership, attrition, and in the peer evaluations made during the training. Analyses conducted on the continuous personality scores demonstrate that these findings are misrepresented or hidden by linear correlations and regressions. As an alternative, I present a configural scoring scheme, couched in a poker analogy, to explain how these individual differences combine to predict the odds of success for each of the 18 personality types studied.