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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Effective management of a virtual workforce

Van der Merwe, I. N. 31 August 2007 (has links)
The problem is that traditional jobs have been office-based, with close supervision. In the Virtual Office (VO) situation managers have a resistance towards the managing of the workforce because they do not know how to manage virtual workers off-site, workers that they cannot see. They feel that managing virtual workers off-site places a huge burden on them. The biggest difference is the shift in management style from direct control to management of results. The biggest challenge for most organisations is to manage the workforce of the VO. The objectives of this research project are to determine how managers can manage a virtual workforce, improve communication and control the workforce. Comprehensive research has been done on the topic VO that includes articles from magazines, newspapers, Internet and textbooks. As sufficient reference resources are not available in South Africa the research was especially based on USA reference resources, due to the reported successful implementation of Virtual Offices in that country. Managers can effective management a virtual workforce by making use of MBO and not by monitoring activities. They can improve communication with the workforce by staying connected and they can control the workforce through feedback and support. This research has proved that the paradigm shift in the corporate world of work, any time, anywhere, in real space or in cyberspace is here to stay. Virtual workers and managers working away from the office is now a reality, and will become more common in the future. Companies who wait for the future to allow the VO to effectively take shape may find themselves at a competitive disadvantage. Now is the time for companies to create the conditions for the VO to emerge. / Business Management / M. Tech. (Business Administration)
72

Contribution à l'agrandissement de l'espace de travail opérationnel des robots parallèles. Vérification du changement de mode d'assemblage et commande pour la traversée des singularités / Contribution to enlargement of parallel robot operationnal workspace. Detection of assembly mode change and advanced control for singularity crossing

Koessler, Adrien 19 December 2018 (has links)
En comparaison avec leurs homologues sériels, les robots parallèles possèdent de nombreux avantages : rigidité, temps de cycle et précision de positionnement. La faible taille de leur espace de travail opérationnel est cependant un inconvénient qui empêche leur développement. L’analyse cinématique décrit la division de l’espace de travail total en aspects, séparés entre eux par des singularités de Type 2. Parmi les solutions d’élargissement de l’espace de travail opérationnel issues de la littérature, que sont comparées entre elles, nous retiendrons la traversée des singularités grâce à une génération de trajectoire et une loi de commande dédiées. Cette solution est cependant sujette aux échecs de traversée et ne permet pas de certifier la réussite de l’opération. La première partie du travail consiste donc à développer un outil permettant de détecter le résultat des traversées. De tels algorithmes n’existent pas dans la littérature ; en effet, les solveurs du problème géométrique direct ne peuvent pas donner de résultats appropriés à proximité des singularités. Cependant les méthodes ensemblistes proposent une manière intéressante de tenir compte de la cinématique du robot. Nous nous basons sur cette considération pour développer un algorithme réalisant le suivi de la pose ainsi que de la vitesse de l’effecteur du robot. En simulation, nous démontrons sa capacité à détecter les changements de mode d’assemblage et son utilité pour générer des trajectoires permettant la traversée. La deuxième problématique consiste à améliorer le suivi de trajectoire par l’utilisation de techniques de commande avancée. Une revue de littérature nous permet d’identifier la commande adaptative et la commande prédictive comme deux schémas intéressants pour notre application. La synthèse d’un loi de commande adaptative par des outils linéaires est proposée et complétée par la prédiction des paramètres dynamiques suivant la méthode Predcitive Functionnal Control. Les gains apportés par les lois de commande proposées sont évalués en simulation. Afin de valider ces contributions, elles sont implémentées sur un robot parallèle plan à deux degrés de liberté nommé DexTAR. Nécessaire à la mise en oeuvre de l’algorithme de détection du mode d’assemblage, un étalonnage géométrique du robot est réalisé et les paramètres estimés sont certifiés de manière ensembliste. La capacité de l’algorithme à statuer sur le mode d’assemblage final est ensuite évaluée sur des trajectoires réelles. Ces résultats sont comparés avec ceux obtenus en simulation. De plus, les lois de commande développées sont implémentées sur le robot DexTAR et testés dans des cas de figure réalistes comme les traversées multiples ou la saisie d’objets.Les propositions formulées dans ce manuscrit permettent de répondre à ces problématiques, afin de faciliter l’utilisation des méthodes d’agrandissement de l’espace de travail par traversée de singularité de Type 2. / Compared to their serial counterparts, parallel robots have the edge in terms of rigidity,cycle time and positioning precision. However, the reduced size of their operationalworkspace is a drawback that limits their use in the industry. Kinematic analysis explainshow the workspace is divided in aspects, separated from each others by so-called Type 2singularities. Among existing solutions for workspace enlargement, which are evaluatedin this thesis, we chose to work on a method based on singularity crossing. This can beachieved thanks to dedicated trajectory generators and control strategies. Yet, failuresin crossing can still happen and crossing success cannot be certified.In consequence, the first part of the thesis consists in the development of an algorithmable to state on the results of a crossing attempt. Such a tool does not exist inthe literature, since solvers for the forward kinematics of parallel robots diverge aroundsingularities. Nonetheless, interval methods allow to bypass this problem by trackingend-effector velocity alongside with its pose. The ability of the algorithm to detect assemblymode change is proven in simulation, and its usefulness for reliable trajectoryplanning is shown.In a second part, we seek to improve trajectory tracking through the use of advancedcontrol techniques. A review on those techniques showed adaptive control and predictivecontrol methods to be well-fitted to our application. Linear synthesis of articularadaptive control is proposed and then derived in order to predict dynamic parametersthanks to the Predictive Functional Control method. Efficiency of the proposed controllaws is evaluated in simulation.1In order to validate both contributions, algorithms and control laws are implementedon a 2-degree of freedom planar parallel robot named DexTAR. As it is mandatory forassembly mode detection, the kinematic calibration of the robot is completed from whichcertified geometric parameters are derived. Assembly mode detection is performed onreal trajectories and results are compared to those obtained in simulation. Moreover,adaptive and predictive control laws are tested in realistic cases of singularity crossingand object manipulation.Overall, proposed contributions answer the problems that were stated previously andform an improvement to the workspace enlargement method based on Type 2 singularitycrossing.
73

ERP and MEG Correlates of Visual Consciousness : An Update

Förster, Jona January 2019 (has links)
Two decades of event-related potential (ERP) research have established that the most consistent correlates of the onset of visual consciousness are the early visual awareness negativity (VAN), a negative component in the N2 time range over posterior electrode sites, and the late positivity (LP), a positive component in the P3 time range over fronto-parietal electrode sites. A review by Koivisto & Revonsuo (2010) had looked at 39 studies and concluded that the VAN is the earliest and most reliable correlate of visual phenomenal consciousness, whereas the LP probably reflects later processes associated with reflective/access consciousness. However, an “early” vs. “late” debate still persists. This thesis provides an update to that earlier review. All ERP and MEG studies that have appeared since 2010 and directly compared ERPs of aware and unaware conditions are considered. The result corroborates the view that VAN is the earliest and most consistent signature of visual phenomenal consciousness, and casts further doubt on the LP as an ERP correlate of consciousness. Important new methodological, empirical, and theoretical developments in the field are described, and the empirical results are related to the theoretical background debates.
74

The Multi - Objective Path Placement Optimization Of Parallel Kinematic Machines

Kucuk, Ali 01 January 2013 (has links) (PDF)
The aim of this study is to obtain optimal position and orientation of a trajectory frame with respect to the fixed frame of the manipulator. The work path which is given in the trajectory frame is also constrained in the workspace of the 3 &ndash / PRS parallel kinematic machine. In the analysis, forward and inverse kinematics solutions are derived as well as the inverse dynamics model using Lagrange&rsquo / s Method. Several algorithms governing the motion of the manipulator are developed. Moreover, optimization goals are defined and evaluated with the genetic algorithm.
75

Enriching Web Applications Efficiently with Real-Time Collaboration Capabilities

Heinrich, Matthias 26 September 2014 (has links) (PDF)
Web applications offering real-time collaboration support (e.g. Google Docs) allow geographically dispersed users to edit the very same document simultaneously, which is appealing to end-users mainly because of two application characteristics. On the one hand, provided real-time capabilities supersede traditional document merging and document locking techniques that distract users from the content creation process. On the other hand, web applications free end-users from lengthy setup procedures and allow for instant application access. However, implementing collaborative web applications is a time-consuming and complex endeavor since offering real-time collaboration support requires two specific collaboration services. First, a concurrency control service has to ensure that documents are synchronized in real-time and that emerging editing conicts (e.g. if two users change the very same word concurrently) are resolved automatically. Second, a workspace awareness service has to inform the local user about actions and activities of other participants (e.g. who joined the session or where are other participants working). Implementing and integrating these two collaboration services is largely ine cient due to (1) the lack of necessary collaboration functionality in existing libraries, (2) incompatibilities of collaboration frameworks with widespread web development approaches as well as (3) the need for massive source code changes to anchor collaboration support. Therefore, we propose a Generic Collaboration Infrastructure (GCI) that supports the e cient development of web-based groupware in various ways. First, the GCI provides reusable concurrency control functionality and generic workspace awareness support. Second, the GCI exposes numerous interfaces to consume these collaboration services in a exible manner and without requiring invasive source code changes. And third, the GCI is linked to a development methodology that e ciently guides developers through the development of web-based groupware. To demonstrate the improved development e ciency induced by the GCI, we conducted three user studies encompassing developers and end-users. We show that the development e ciency can be increased in terms of development time when adopting the GCI. Moreover, we also demonstrate that implemented collaborative web applications satisfy end-user needs with respect to established software quality characteristics (e.g. usability, reliability, etc.). / Webbasierte, kollaborative Echtzeitanwendungen (z.B. Google Docs) erlauben es geografisch verteilten Nutzern, Dokumente gemeinschaftlich und simultan zu bearbeiten. Die Implementierung kollaborativer Echtzeitanwendungen ist allerdings aufwendig und komplex, da einerseits eine Nebenläufigkeitskontrolle von Nöten ist und andererseits die Nachvollziehbarkeit von nicht-lokalen Interaktionen mit dem gemeinsamen virtuellen Arbeitsraum gewährleistet sein muss (z.B. wer editiert wo). Um die Entwicklung kollaborativer Echtzeitanwendungen effizient zu gestalten, wurde eine Generische Kollaborationsinfrastruktur (GKI) entwickelt. Diese GKI stellt sowohl eine Nebenläufigkeitskontrolle als auch Komponenten zur Nachvollziehbarkeit von nicht-lokalen Interaktionen auf eine wiederverwendbare und nicht-invasive Art und Weise zur Verfügung. In drei dedizierten Studien, die sowohl Entwickler als auch Endanwender umfassten, wurde die Entwicklungseffizienz der GKI nachgewiesen. Dabei wurde die Entwicklungszeit, der Umfang des Quelltextes als auch die Gebrauchstauglichkeit analysiert.
76

La génération des connaissances et la conception des artefacts visuels : le cas de l'aménagement des espaces de travail dans les entreprises / Knowledge generation and visuel's artifact conception : case of workspace planning within the enterprises

Chouki, Mourad 26 November 2012 (has links)
Actuellement, le développement du travail en mode projet, ainsi que le travail en réseaux, entraînent de profondes modifications dans la manière de concevoir les espaces de travail et les bureaux. Les entreprises qui conçoivent ces espaces associent souvent des architectes et des designers.La thèse a pour objet de répondre à la question suivante : comment les connaissances nouvelles sont elles générées dans les activités de conception relatives au domaine de l'aménagement des espaces de travail ?Le premier chapitre s'articulera autour des différents travaux relatifs aux activités deconception (travaux de Lebahar, Hatchuel et Visser, etc.). Le second s'intéressera aux différentes théories relatives à la génération des connaissances (travaux de Nonaka, Tsoukas et Engeström, etc).Afin de répondre à notre question de recherche, nous avons mis en place un dispositif d'observation de longue durée au sein des entreprises étudiées (approche de nature ethnométhdologique). Il s'agit de deux entreprises parisiennes spécialisées dans l'aménagement des espaces de travail: Génie des Lieux et Workspace CBRE.Nous avons montré que des difficultés d'intercompréhension apparaissent dans les activités de conception. Ces obstacles sont dûs à l'existence des connaissances tacites relationnelles au sens d'Harry Collins. Ces dernières peuvent être rendues explicites par la conception d'objets intermédiaires. Nous avons vu également comment la conception des artefacts en deux dimensions et en trois dimensions permet la génération des connaissances nouvelles et utiles dans un projet d'aménagement d'espaces de travail. / The development of this work is currently carried out in a project mode, since working in the network requires deep modifications in a way of conceiving the workspaces as well as the offices. The enterprises that conceive these spaces often associate both the designers and the architects.The purpose of this present thesis is to answer the flowing question: how are the recent knowledges generated in the conception activities which appear in the field of work space planning?The first chapter focuses on the works related to the conception activities (works of Lebahar, Hatchuel and Visser...etc...). The second deals with the different theories relating to the generation of knowledge (works of Nonaka, Tsoukas and Engeström... etc...).To answer our research question, we have installed a device which requires a long_term intervention inside the enterprises meant for study (ethnomethodological approach). There are two Parisian enterprises that specialize in work space planning: (GENIE DES LIEUX and workspace CBRE).During the work, we have shown some difficulty intercomprehension that emerged in the conception activities. We have concluded, as a result, that these obstacles were due to relational tacit knowledges (RTK) according to Harry Collins theory. However these difficulties can be made explicit by the conception of intermediate objects.We have also noticed that ho when conceiving the artifacts into two and three dimensions, this allows the generation of new and useful knowledges in a project of work space planning.
77

Effective management of a virtual workforce

Van der Merwe, I. N. 31 August 2007 (has links)
The problem is that traditional jobs have been office-based, with close supervision. In the Virtual Office (VO) situation managers have a resistance towards the managing of the workforce because they do not know how to manage virtual workers off-site, workers that they cannot see. They feel that managing virtual workers off-site places a huge burden on them. The biggest difference is the shift in management style from direct control to management of results. The biggest challenge for most organisations is to manage the workforce of the VO. The objectives of this research project are to determine how managers can manage a virtual workforce, improve communication and control the workforce. Comprehensive research has been done on the topic VO that includes articles from magazines, newspapers, Internet and textbooks. As sufficient reference resources are not available in South Africa the research was especially based on USA reference resources, due to the reported successful implementation of Virtual Offices in that country. Managers can effective management a virtual workforce by making use of MBO and not by monitoring activities. They can improve communication with the workforce by staying connected and they can control the workforce through feedback and support. This research has proved that the paradigm shift in the corporate world of work, any time, anywhere, in real space or in cyberspace is here to stay. Virtual workers and managers working away from the office is now a reality, and will become more common in the future. Companies who wait for the future to allow the VO to effectively take shape may find themselves at a competitive disadvantage. Now is the time for companies to create the conditions for the VO to emerge. / Business Management / M. Tech. (Business Administration)
78

Outils numériques pour la conception de mécanismes / Numerical tools for mechanism design

Hentz, Gauthier 18 September 2017 (has links)
Dans le contexte médico-chirurgical, la robotique peut être d’un grand intérêt pour des procédures plus sûres et plus précises. Les contraintes d’encombrement sont cependant très fortes et des mobilités complexes peuvent être nécessaires. A ce jour, la conception de mécanismes non conventionnels dédiés est alors difficile à réaliser faute d’outils génériques permettant une évaluation rapide de leurs performances. Cette thèse associe la continuation de haut-degré et la différentiation automatique pour répondre à cette problématique en introduisant une méthode de modélisation et un formalisme génériques pour la conception de mécanismes. Nos contributions concernent en particulier le développement d’outils numériques pour l’évaluation de l’espace de travail, et de la localisation et la nature des singularités d’un mécanisme, et une analyse de sensibilité de haut-degré. Ceux-ci sont évalués sur des mécanismes de référence. / In the medical and surgical background, robotics can be of great interest for safer and more accurate procedures. Size constraints are however strong and complex movements may be necessary. To date, the design of dedicated non-conventional mechanisms is then a difficult task because of a lack of generic tools allowing a fast evaluation of their performances. This thesis combines higher-order continuation and automatic differentiation to adress this issue through the introduction of a generic modelling method and a generic formalism for mechanism design. Our contributions especially concern the development of numerical tools for the evaluation of the workspace, of the singularity localization and nature, and for a higher-order sensitivity analysis. These tools are evaluated on reference mechanisms.
79

The Activity-based Workspace Effect on Organisational Behaviour : A Case Study of Kognity

Färm Grufman, Nici, Roth de Albuquerque, Sara January 2018 (has links)
In light of contradictory findings in previous research regarding the activity-based workspaces’ effect on organisational behaviour, this study applies The Activity-based Flexible Office Model on the company Kognity, which recently implemented this office concept. The purpose is to test if this may increase understanding of consequences on organisational behaviour from implementing an activity-based workspace. Semi-structured interviews and observations at Kognity are used as methods for the collection of data for the study. As secondary data, results from web-based surveys conducted by Kognity are used. Furthermore, previous research within the field of organisational behaviour and activity-based office concepts are used to give the study credibility and to gain a deeper insight of the topic. The theoretical framework for this study is based on The Activity Based Flexible Office Model and Maslow's Hierarchy of Needs Theory. The conclusion is that the activity-based workspace does affect organisational behaviour. Applying the Activity Based Flexible Office Model increases the understanding of what the implementation of an activity-based workspace may lead to in terms of organisational behaviour. The model is a useful tool which shows that task-related moderators can determine in what extent the workspace effects organisational behaviour, depends on individual values and task requirements. Further, application of Maslow’s Hierarchy of Needs shows that the higher needs in Maslow’s hierarchy of needs may be met through the freedom of choice within an activity-based workspace. / Tidigare forskning, som berör vilka konsekvenser implementeringen av ett aktivitetsbaserat kontor har på de anställda samt hur det påverkar organisatoriskt beteende, har visat sig vara motsägelsefull. För att bidra till ökad kunskap, applicerar den här studien modellen The Activity-based Flexible Office Model på ett företag vid namn Kognity. Kognity har nyligen implementerat ett aktivitetsbaserat kontor. Semi-strukturerade intervjuer och observationer utfördes på Kognity. Studien använde sig även av sekundärdata i form av resultat från enkäter som Kognity utför själva. Den teoretiska referensramen som applicerades på den här studien var The Activity-based Flexible Office Model samt Maslows behovsteori. Studiens slutsatser är att organisatoriskt beteende påverkas av implementerandet av ett aktivitetsbaserat kontor. Genom att applicera The Activity-based Flexible Office Model ges bidrag till ökad förståelse för konsekvenserna av implementerandet av ett aktivitetsbaserat kontor. Modellen är ett användbart verktyg för att undersöka vilka faktorer som påverkar och vilka omständigheter som kan påverka ytterligare. Vidare visar applicerandet av Maslows behovsteori att ett aktivitetsbaserat kontor skulle kunna möta de högre behoven i teorin tack vare anställdas frihet att välja sin arbetsplats.
80

Event-related potential correlates of visual consciousness : a review of theories and empirical studies

Kastrati, Granit January 2012 (has links)
Two influential theories of consciousness disagree about if consciousness initially arises along the occipitotemporal cortex to later engage frontoparietal regions and attentional mechanisms, or if it necessarily requires the latter. Consequently, different predictions are made about the temporal emergence of consciousness. The event-related potential (ERP) technique can be used to resolve the issue. It can temporally track neural activity of consciously perceived stimuli relative to stimuli bypassing consciousness. This essay describes the two theories and reviews ERP studies on visual consciousness and its relationship to attention. Three ERP correlates of consciousness have been proposed. The question is if they should be interpreted as supporting the one or the other theory. Most plausibly, visual consciousness arises along occipitotemporal regions and later incorporates frontal areas engaging higher cognitive functions. Importantly it seems that consciousness cannot arise without spatial attention/parietal regions.

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