404 research outputs found
A framework for real time collaborative editing in a mobile replicated architecture
Mobile collaborative work is a developing sub-area of Computer Supported Collaborative Work (CSCW). The future of this field will be marked by a significant increase in mobile device usage as a tool for co-workers to cooperate, collaborate and work on a shared workspace in real-time to produce artefacts such as diagrams, text and graphics regardless of their geographical locations. A real-time collaboration editor can utilise a centralised or a replicated architecture. In a centralised architecture, a central server holds the shared document as well as manages the various aspects of the collaboration, such as the document consistency, ordering of updates, resolving conflicts and the session membership. Every user's action needs to be propagated to the central server, and the server will apply it to the document to ensure it results in the intended document state. Alternatively, a decentralised or replicated architecture can be used where there is no central server to store the shared document. Every participating site contains a copy of the shared document (replica) to work on separately. Using this architecture, every user's action needs to be broadcast to all participating sites so each site can update their replicas accordingly. The replicated architecture is attractive for such applications, especially in wireless and ad-hoc networks, since it does not rely on a central server and a user can continue to work on his or her own local document replica even during disconnection period. However, in the absence of a dedicated server, the collaboration is managed by individual devices. This presents challenges to implement collaborative editors in a replicated architecture, especially in a mobile network which is characterised by limited resource reliability and availability. This thesis addresses challenges and requirements to implement group editors in wireless ad-hoc network environments where resources are scarce and the network is significantly less stable and less robust than wired fixed networks. The major contribution of this thesis is a proposed framework that comprises the proposed algorithms and techniques to allow each device to manage the important aspects of collaboration such as document consistency, conflict handling and resolution, session membership and document partitioning. Firstly, the proposed document consistency algorithm ensures the document replicas held by each device are kept consistent despite the concurrent updates by the collaboration participants while taking into account the limited resource of mobile devices and mobile networks. Secondly, the proposed conflict management technique provides users with conflict status and information so that users can handle and resolve conflicts appropriately. Thirdly, the proposed membership management algorithm ensures all participants receive all necessary updates and allows users to join a currently active collaboration session. Fourthly, the proposed document partitioning algorithm provides flexibility for users to work on selected parts of the document and reduces the resource consumption. Finally, a basic implementation of the framework is presented to show how it can support a real time collaboration scenario
A theory and model for the evolution of software services
Software services are subject to constant change and variation. To control service development, a service developer needs to know why a change was made, what are its implications and whether the change is complete. Typically, service clients do not perceive the upgraded service immediately. As a consequence, service-based applications may fail on the service client side due to changes carried out during a provider service upgrade. In order to manage changes in a meaningful and effective manner service clients must therefore be considered when service changes are introduced at the service provider's side. Otherwise such changes will most certainly result in severe application disruption. Eliminating spurious results and inconsistencies that may occur due to uncontrolled changes is therefore a necessary condition for the ability of services to evolve gracefully, ensure service stability, and handle variability in their behavior. Towards this goal, this work presents a model and a theoretical framework for the compatible evolution of services based on well-founded theories and techniques from a number of disparate fields.
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Practical theorising for the implementation of educational change: Evidence from sub-Saharan Africa
New school curricula across Africa are calling for new approaches to learning and teaching. In response, much educational development work focuses on supporting pedagogic change. The successful implementation of educational change is challenging, attested by persistently low achievement levels, yet it remains under-theorised. However, âimplementationâ as a process is well-theorised in the field of healthcare. This paper explains a middle-range sociological theory â Normalisation Process Theory â which seeks to describe how new practices become normalised. Drawing on evidence from the field, it argues that NPT, although developed in healthcare settings, offers insights which could benefit the implementation of educational development project
A theory and model for the evolution of software services.
Software services are subject to constant change and variation. To control service development, a service developer needs to know why a change was made, what are its implications and whether the change is complete. Typically, service clients do not perceive the upgraded service immediately. As a consequence, service-based applications may fail on the service client side due to changes carried out during a provider service upgrade. In order to manage changes in a meaningful and effective manner service clients must therefore be considered when service changes are introduced at the service provider's side. Otherwise such changes will most certainly result in severe application disruption. Eliminating spurious results and inconsistencies that may occur due to uncontrolled changes is therefore a necessary condition for the ability of services to evolve gracefully, ensure service stability, and handle variability in their behavior. Towards this goal, this work presents a model and a theoretical framework for the compatible evolution of services based on well-founded theories and techniques from a number of disparate fields.
Handling High-Level Model Changes Using Search Based Software Engineering
Model-Driven Engineering (MDE) considers models as first-class artifacts during the software
lifecycle. The number of available tools, techniques, and approaches for MDE is increasing as its
use gains traction in driving quality, and controlling cost in evolution of large software systems.
Software models, defined as code abstractions, are iteratively refined, restructured, and evolved.
This is due to many reasons such as fixing defects in design, reflecting changes in requirements,
and modifying a design to enhance existing features.
In this work, we focus on four main problems related to the evolution of software models: 1) the
detection of applied model changes, 2) merging parallel evolved models, 3) detection of design
defects in merged model, and 4) the recommendation of new changes to fix defects in software
models.
Regarding the first contribution, a-posteriori multi-objective change detection approach has been
proposed for evolved models. The changes are expressed in terms of atomic and composite
refactoring operations. The majority of existing approaches detects atomic changes but do not
adequately address composite changes which mask atomic operations in intermediate models.
For the second contribution, several approaches exist to construct a merged model by
incorporating all non-conflicting operations of evolved models. Conflicts arise when the
application of one operation disables the applicability of another one. The essence of the problem
is to identify and prioritize conflicting operations based on importance and context â a gap in
existing approaches. This work proposes a multi-objective formulation of model merging that
aims to maximize the number of successfully applied merged operations.
For the third and fourth contributions, the majority of existing works focuses on refactoring at
source code level, and does not exploit the benefits of software design optimization at model
level. However, refactoring at model level is inherently more challenging due to difficulty in
assessing the potential impact on structural and behavioral features of the software system. This requires analysis of class and activity diagrams to appraise the overall system quality, feasibility,
and inter-diagram consistency. This work focuses on designing, implementing, and evaluating a
multi-objective refactoring framework for detection and fixing of design defects in software
models.Ph.D.Information Systems Engineering, College of Engineering and Computer ScienceUniversity of Michigan-Dearbornhttp://deepblue.lib.umich.edu/bitstream/2027.42/136077/1/Usman Mansoor Final.pdfDescription of Usman Mansoor Final.pdf : Dissertatio
Utilizing Reinforcement Learning and Computer Vision in a Pick-And-Place Operation for Sorting Objects in Motion
This master's thesis studies the implementation of advanced machine learning (ML) techniques in industrial automation systems, focusing on applying machine learning to enable and evolve autonomous sorting capabilities in robotic manipulators. In particular, Inverse Kinematics (IK) and Reinforcement Learning (RL) are investigated as methods for controlling a UR10e robotic arm for pick-and-place of moving objects on a conveyor belt within a small-scale sorting facility. A camera-based computer vision system applying YOLOv8 is used for real-time object detection and instance segmentation. Perception data is utilized to ascertain optimal grip points, specifically through an implemented algorithm that outputs optimal grip position, angle, and width. As the implemented system includes testing and evaluation on a physical system, the intricacies of hardware control, specifically the reverse engineering of an OnRobot RG6 gripper is elaborated as part of this study.
The system is implemented on the Robotic Operating System (ROS), and its design is in particular driven by high modularity and scalability in mind. The camera-based vision system serves as the primary input, while the robot control is the output. The implemented system design allows for the evaluation of motion control employing both IK and RL. Computation of IK is conducted via MoveIt2, while the RL model is trained and computed in NVIDIA Isaac Sim.
The high-level control of the robotic manipulator was accomplished with use of Proximal Policy Optimization (PPO). The main result of the research is a novel reward function for the pick-and-place operation that takes into account distance and orientation from the target object. In addition, the provided system administers task control by independently initializing pick-and-place operation phases for each environment. The findings demonstrate that PPO was able to significantly enhance the velocity, accuracy, and adaptability of industrial automation. Our research shows that accurate control of the robot arm can be reached by training the PPO Model purely by applying a digital twin simulation
Proposition de nouvelles fonctionnalités WikiSIG pour supporter le travail collaboratif en Geodesign
LâĂ©mergence du Web 2.0 se matĂ©rialise par de nouvelles technologies (API, AjaxâŠ), de nouvelles pratiques (mashup, geotaggingâŠ) et de nouveaux outils (wiki, blogâŠ). Il repose principalement sur le principe de participation et de collaboration. Dans cette dynamique, le Web Ă caractĂšre spatial et cartographique câest-Ă -dire, le Web gĂ©ospatial (ou GĂ©oWeb) connait lui aussi de fortes transformations technologiques et sociales. Le GĂ©oWeb 2.0 participatif se matĂ©rialise en particulier par des mashups entre wikis et gĂ©obrowsers (ArgooMap, Geowiki, WikiMapia, etc.). Les nouvelles applications nĂ©es de ces mashups Ă©voluent vers des formes plus interactives dâintelligence collective. Mais ces applications ne prennent pas en compte les spĂ©cificitĂ©s du travail collaboratif, en particulier la gestion de traçabilitĂ© ou lâaccĂšs dynamique Ă lâhistorique des contributions. Le Geodesign est un nouveau domaine fruit de lâassociation des SIG et du design, permettant Ă une Ă©quipe multidisciplinaire de travailler ensemble. Compte tenu de son caractĂšre Ă©mergent, le Geodesign nâest pas assez dĂ©fini et il requiert une base thĂ©orique innovante, de nouveaux outils, supports, technologies et pratiques afin de s'adapter Ă ses exigences complexes. Nous proposons dans cette thĂšse de nouvelles fonctionnalitĂ©s de type WikiSIG, bĂąties sur les principes et technologies du GĂ©oWeb 2.0 et visant en particulier Ă supporter la dimension collaborative du processus de Geodesign. Le WikiSIG est dotĂ© de fonctionnalitĂ©s wiki dĂ©diĂ©es Ă la donnĂ©e gĂ©ospatiale (y compris dans sa composante gĂ©omĂ©trique : forme et localisation) permettant dâassurer, de maniĂšre dynamique, la gestion documentĂ©e des versions des objets et lâaccĂšs Ă ces versions (et de leurs mĂ©tadonnĂ©es), facilitant ainsi le travail collaboratif en Geodesign. Nous proposons Ă©galement la deltification qui consiste en la capacitĂ© de comparer et dâafficher les diffĂ©rences entre deux versions de projets. Finalement la pertinence de quelques outils du gĂ©otraitement et « sketching » est Ă©voquĂ©e. Les principales contributions de cette thĂšse sont dâune part dâidentifier les besoins, les exigences et les contraintes du processus de Geodesign collaboratif, et dâautre part de proposer des nouvelles fonctionnalitĂ©s WikiSIG rĂ©pondant au mieux Ă la dimension collaborative du processus. Pour ce faire, un cadre thĂ©orique est dressĂ© oĂč nous avons identifiĂ© les exigences du travail collaboratif de Geodesign et proposĂ© certaines fonctionnalitĂ©s WikiSIG innovantes qui sont par la suite formalisĂ©s en diagrammes UML. Une maquette informatique est aussi dĂ©veloppĂ©e de façon Ă mettre en oeuvre ces fonctionnalitĂ©s, lesquelles sont illustrĂ©es Ă partir dâun cas dâĂ©tude simulĂ©, traitĂ© comme preuve du concept. La pertinence de ces fonctionnalitĂ©s dĂ©veloppĂ©es proposĂ©es est finalement validĂ©e par des experts Ă travers un questionnaire et des entrevues. En rĂ©sumĂ©, nous montrons dans cette thĂšse lâimportance de la gestion de la traçabilitĂ© et comment accĂ©der dynamiquement Ă lâhistorique dans un processus de Geodesign. Nous proposons aussi dâautres fonctionnalitĂ©s comme la deltification, le volet multimĂ©dia supportant lâargumentation, les paramĂštres qualifiant les donnĂ©es produites, et la prise de dĂ©cision collective par consensus, etc.The emergence of Web 2.0 is materialized by new technologies (APIs, Ajax ...), by new practices (mashup, geotagging ...) and by new tools (wiki, blog ...). It is primarily based on the principle of participation and collaboration. In this dynamic, the web mapping with spatial character or simply called Geospatial Web (or Geoweb) evolves by strong technological and social changes. Participatory GeoWeb 2.0 is materialized in particular by mashups among wikis and gĂ©obrowsers (ArgooMap, Geowiki, WikiMapia, etc.). The new applications resulting from these mashups are moving towards more interactive forms of collective intelligence. However, these applications do not take into account the collaborative work or the traceability management or the dynamic access to the history of contributions. The Geodesign is a new area, which is the coupling between GIS and design, allowing a multidisciplinary team to work together. As it is an emergent term, the Geodesign has not be well defined and it requires innovative theoretical basis, new tools, media, technologies and practices to fit its complex requirements. We propose precisely in this thesis new features of WikiGIS, which is built on Web 2.0 technologies, and GeoWeb 2.0 aiming in particular to support the collaborative dimension of Geodesign process. The WikiGIS consists of wiki features for the geospatial data (including its geometric component: shape and location) to ensure, dynamically, the documented release management objects and access to these versions (and metadata), facilitating collaborative work on Geodesign. It aims to produce geographic information, while ensuring the quality and credibility of data created. We propose the âdeltificationâ as one of the innovative features of WikiGIS, it is the ability to compare and display the differences between two versions of a project. Finally, the relevance of some geoprocessing and "sketching" tools is mentioned. The main contributions of the present thesis are firstly identifying the needs, requirements and constraints of collaborative Geodesign process, and secondly to offer new features of WikiSIG best meeting to the collaborative dimension of this process. For this, a theoretical framework is drawn up which we identified the requirements of the collaborative Geodesign process and we proposed some innovative features that are subsequently formalized by UML. A user mock-up is developed in order to show the WikiGIS features, which are illustrated on a simulated case study, treated as proof of concept. Finally, these concepts are ultimately validated by experts through a questionnaire and interviews. Briefly, we have amply demonstrated in this thesis the importance of traceability management and how to dynamically access in the historic of Geodesign process and we have proposed other features like deltification, multi-media component that supports the arguments, parameters describing the data produced, decision making by consensus, etc
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