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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.
261

A contextual AR model based system on-site construction planning

Moore, Nigel Jonathan January 2013 (has links)
The creation of an effective construction schedule is fundamental to the successful completion of a construction project. Effectively communicating the temporal and spatial details of this schedule are vital, however current planning approaches often lead to multiple or misinterpretations of the schedule throughout the planning team. Four Dimensional Computer Aided Design (4D CAD) has emerged over the last twenty years as an effective tool during construction project planning. In recent years Building Information Modelling (BIM) has emerged as a valuable approach to construction informatics throughout the whole lifecycle of a building. Additionally, emerging trends in location-aware and wearable computing provide a future potential for untethered, contextual visualisation and data delivery away from the office. The purpose of this study was to develop a novel computer-based approach, to facilitate on-site 4D construction planning through interaction with a 3D construction model and corresponding building information data in outdoor Augmented Reality (AR). Based on a wide ranging literature review, a conceptual framework was put forward to represent software development requirements to support the sequencing of construction tasks in AR. Based on this framework, an approach was developed that represented the main processes required to plan a construction sequence using an onsite model based 4D methodology. Using this proposed approach, a prototype software tool was developed, 4DAR. The implemented tool facilitated the mapping of elements within an interactive 3D model with corresponding BIM data objects to provide an interface for two way communication with the underlying Industry Foundation Class (IFC) data model. Positioning data from RTK-GPS and an electronic compass enabled the geo-located 3D model to be registered in world coordinates and visualised using a head mounted display fitted with a ii forward facing video camera. The scheduling of construction tasks was achieved using a novel interactive technique that negated the need for a previous construction schedule to be input into the system. The resulting 4D simulation can be viewed at any time during the scheduling process, facilitating an iterative approach to project planning to be adopted. Furthermore, employing the IFC file as a central read/write repository for schedule data reduces the amount of disparate documentation and centralises the storage of schedule information, while improving communication and facilitating collaborative working practices within a project planning team. Post graduate students and construction professionals evaluated the implemented prototype tool to test its usefulness for construction planning requirements. It emerged from the evaluation sessions that the implemented tool had achieved the essential requirements highlighted in the conceptual framework and proposed approach. Furthermore, the evaluators expressed that the implemented software and proposed novel approach to construction planning had potential to assist with the planning process for both experienced and inexperienced construction planners. The following contributions to knowledge have been made by this study in the areas of 4D CAD, construction applications of augmented reality and Building Information Modelling; · 4D Construction Planning in Outdoor Augmented Reality (AR) · The development of a novel 4D planning approach through decomposition · The deployment of Industry Foundation Classes (IFC) in AR · Leveraging IFC files for centralised data management within real time planning and visualisation environment.
262

Convergence in mixed reality-virtuality environments : facilitating natural user behavior

Johansson, Daniel January 2012 (has links)
This thesis addresses the subject of converging real and virtual environments to a combined entity that can facilitate physiologically complying interfaces for the purpose of training. Based on the mobility and physiological demands of dismounted soldiers, the base assumption is that greater immersion means better learning and potentially higher training transfer. As the user can interface with the system in a natural way, more focus and energy can be used for training rather than for control itself. Identified requirements on a simulator relating to physical and psychological user aspects are support for unobtrusive and wireless use, high field of view, high performance tracking, use of authentic tools, ability to see other trainees, unrestricted movement and physical feedback. Using only commercially available systems would be prohibitively expensive whilst not providing a solution that would be fully optimized for the target group for this simulator. For this reason, most of the systems that compose the simulator are custom made to facilitate physiological human aspects as well as to bring down costs. With the use of chroma keying, a cylindrical simulator room and parallax corrected high field of view video see-though head mounted displays, the real and virtual reality are mixed. This facilitates use of real tool as well as layering and manipulation of real and virtual objects. Furthermore, a novel omnidirectional floor and thereto interface scheme is developed to allow limitless physical walking to be used for virtual translation. A physically confined real space is thereby transformed into an infinite converged environment. The omnidirectional floor regulation algorithm can also provide physical feedback through adjustment of the velocity in order to synchronize virtual obstacles with the surrounding simulator walls. As an alternative simulator target use, an omnidirectional robotic platform has been developed that can match the user movements. This can be utilized to increase situation awareness in telepresence applications.
263

Assessing the effects of augmented reality on the spatial skills of postsecondary construction management students in the U.S.

Kim, Jeff 27 May 2016 (has links)
There is a continual challenge within the construction industry to meet schedule, budget, and quality expectations. At the same time, there is an underlying problem where the older and more experienced workforce is retiring from industry at a faster rate than the newer workforce can replace them. As the more experienced workforce departs from the industry, they are taking with them much-needed skills and experience that fail to get transitioned to the newer and less experienced workforce. Among these skills are spatial skills. The construction industry has already caught on that this is a serious problem that they must contend with, and so, they have looked to the postsecondary institutions to help resolve it. However, the postsecondary institutions have a problem of their own, whereby they commonly default to passive teaching techniques that are not well suited to teaching spatial skills. So, therefore, there is a need to graduate construction management students with better spatial skills in order to meet the necessities of industry. Along with this, is the need for academia to reconsider teaching styles to better train spatial skills. Spatial skills, it has been found, are better retained when active and collaborative teaching engagements are arranged. Therefore, identifying and testing a practical and non-interfering classroom tool that students can easily use, would be the most favorable way to overcome academia’s tendency towards passive teaching. Spatial skills are needed in every part of the construction industry. In fact, everyday simple tasks require spatial skills and while these skills are honed over time, more refined skills, capable of interpreting abstract space, are required to assemble a complex construction project. Construction projects are getting more complex and often the design involves some measure of abstract thinking. Teaching these abstract-based spatial skills in postsecondary institutions has typically been done through drafting and plan reading courses, with some success. However, the need from industry is not being fully met with these skills and so an alternative solution is recommended. While Building Information Modeling (BIM) has become an adequate solution to aid in the understanding and planning of highly abstract designs, successfully using it requires excellent spatial skills. Consequently, it would be advantageous if those spatial skills were developed before students were introduced to BIM. Augmented reality is a collection of technologies that allows a user to view the “real” world with additional information that is intended to provide a better understanding of what is being observed. Augmented reality already has applications in many industries and is fast becoming a proven technology. With the availability of smaller and more powerful consumer mobile devices, augmented reality has the potential of becoming a more ubiquitous and practical tool. Recognizing that this technology can be practical, non-interfering, and known by the masses makes it an excellent solution for the classroom. Therefore, this research will study the use of an augmented reality tool to determine if there is an improvement of spatial skills in terms of accuracy, time to execute, and the retention of concepts over time. Furthermore, a separate analysis will be conducted to determine if the teaching tool is a benefit or disruption to the overall learning experience.
264

Going Beyond the Desktop Computer with an Attitude

Sokoler, Tomas January 2004 (has links)
This dissertation is based upon the work within a number of research projects, five of which are presented in detail. The work follows the direction of research laid out by the Ubiquitous Computing and Augmented Reality research programs and concerns the broad question of where to go as we seek to take digital technology, and human interactions with this technology, beyond the traditional desktop computer. The work presented takes a design-oriented approach to Human Computer Interaction research. Five prototype systems are presented: Ambient displays for remote awareness, a navigation device providing guidance through tactile cues, a personal device for wastewater plant operators, paper cards enabling control of video playback, and a cell phone that enables you to ‘talk silent’. It is discussed how these prototypes, despite obvious differences, all reflect the same overall attitude towards the role of digital technology. It is an attitude emphasizing that integration of digital technology with everyday human activities means making computational power manifest as part of a larger patchwork of resources. Furthermore, it is an attitude promoting the design of digital technology that leaves the control and initiative with people and their earned ability to take appropriate action when faced with the particularities of the social and physical settings encountered in everyday life beyond the computer screen. In other words, this dissertation brings forward, by using five prototypes as examples, an attitude that encourages us to recognize, embrace, and take advantage of, the fact that human interaction with digital technology takes place, not in a vacuum, but in a rich and diverse world full of many resources for human action other than the digital technology we bring about. / <p>In collaboration with School of Arts and Communication, Malmö University, Sweden.</p>
265

LOCATIVE MEDIA, AUGMENTED REALITIES AND THE ORDINARY AMERICAN LANDSCAPE

Boulton, Andrew 01 January 2013 (has links)
This dissertation investigates the role of annotative locative media in mediating experiences of place. The overarching impetus motivating this research is the need to bring to bear the theoretical and substantive concerns of cultural landscape studies on the development of a methodological framework for interrogating the ways in which annotative locative media reconfigure experiences of urban landscapes. I take as my empirical cases i) Google Maps with its associated Street View and locational placemark interface, and ii) Layar, an augmented reality platform combining digital mapping and real-time locational augmentation. In the spirit of landscape studies’ longstanding and renewed interest in what may be termed “ordinary” residential landscapes, and reflecting the increasing imbrication of locative media technologies in everyday lives, the empirical research is based in Kenwick, a middleclass, urban residential neighborhood in Lexington, Kentucky. Overall, I present an argument about the need to consider the digital, code (i.e. software), and specifically locative media, in the intellectual context of critical geographies in general and cultural landscape studies in particular.
266

Security and privacy in perceptual computing

Jana, Suman 18 September 2014 (has links)
Perceptual, "context-aware" applications that observe their environment and interact with users via cameras and other sensors are becoming ubiquitous on personal computers, mobile phones, gaming platforms, household robots, and augmented-reality devices. This dissertation's main thesis is that perceptual applications present several new classes of security and privacy risks to both their users and the bystanders. Existing perceptual platforms are often completely inadequate for mitigating these risks. For example, we show that the augmented reality browsers, a class of popular perceptual platforms, contain numerous inherent security and privacy flaws. The key insight of this dissertation is that perceptual platforms can provide stronger security and privacy guarantees by controlling the interfaces they expose to the applications. We explore three different approaches that perceptual platforms can use to minimize the risks of perceptual computing: (i) redesigning the perceptual platform interfaces to provide a fine-grained permission system that allows least-privileged application development; (ii) leveraging existing perceptual interfaces to enforce access control on perceptual data, apply algorithmic privacy transforms to reduce the amount of sensitive content sent to the applications, and enable the users to audit/control the amount of perceptual data that reaches each application; and (iii) monitoring the applications' usage of perceptual interfaces to find anomalous high-risk cases. To demonstrate the efficacy of our approaches, first, we build a prototype perceptual platform that supports fine-grained privileges by redesigning the perceptual interfaces. We show that such a platform not only allows creation of least-privileged perceptual applications but also can improve performance by minimizing the overheads of executing multiple concurrent applications. Next, we build DARKLY, a security and privacy-aware perceptual platform that leverages existing perceptual interfaces to deploy several different security and privacy protection mechanisms: access control, algorithmic privacy transforms, and user audit. We find that DARKLY can run most existing perceptual applications with minimal changes while still providing strong security and privacy protection. Finally, We introduce peer group analysis, a new technique that detects anomalous high-risk perceptual interface usages by creating peer groups with software providing similar functionality and comparing each application's perceptual interface usages against those of its peers. We demonstrate that such peer groups can be created by leveraging information already available in software markets like textual descriptions and categories of applications, list of related applications, etc. Such automated detection of high-risk applications is essential for creating a safer perceptual ecosystem as it helps the users in identifying and installing safer applications with any desired functionality and encourages the application developers to follow the principle of least privilege. / text
267

Augmented Reality for Spatial Perception in the Computer Assisted Surgical Trainer

Wagner, Adam, Wagner, Adam January 2017 (has links)
Traditional laparoscopic surgery continues to require significant training on the part of the surgeon before entering the operating room. Augmented Reality (AR) has been investigated for use in visual guidance in training and during surgery, but little work is available investigating the effectiveness of AR techniques in providing the user better awareness of depth and space. In this work we propose several 2D AR overlays for visual guidance in training for laparoscopic surgery, with the goal of aiding the user's perception of depth and space in that limiting environment. A pilot study of 30 subjects (22 male and 8 female) was performed with results showing the effect of the various overlays on subject performance of a path following task in the Computer Assisted Surgical Trainer (CAST-III) system developed in the Model Based Design Lab. Deviation, economy of movement, and completion time are considered as metrics. Providing a reference indicator for the nearest point on the optimal path is found to result in significant reduction (p < 0.05) in subject deviation from the path. The data also indicates a reduction in subject deviation along the depth axis and total path length with overlays designed to provide depth information. Avenues for further investigation are presented.
268

Master ’s Programme in Information Technology: Using multiple Leap Motion sensors in Assembly workplace in Smart Factory

Karimi, Majid January 2016 (has links)
The new industry revolution creates a vast transformation in the manufacturing methods. Embedded Intelligence and communication technologies facilitate the execution of the smart factory. It can provide lots of features for strong customization of products. Assembly system is a critical segment of the smart factory. However, the complexity of production planning and the variety of products being manufactured, persuade the factories to use different methods to guide the workers for unfamiliar tasks in the assembly section. Motion tracking is the process of capturing the movement of human body or objects which has been used in different industrial systems. It can be integrated to a wide range of applications such as interacting with computers, games and entertainment, industry, etc. Motion tracking can be integrated to assembly systems and it has the potential to create an improvement in this industry as well. But the integration of motion tracking in industrial processes is still not widespread. This thesis work provides a fully automatic tracking solution for future systems in manufacturing industry and other fields. In general a configurable, flexible, and scalable motion tracking system is created in this thesis work to amend the tracking process. According to our environment, we have done a research between different motion tracking methods and technologies including Kinect and Leap Motion sensor, and finally the leap motion sensor is selected as the most appropriate method, because it fulfils our demands in this project. Multiple Leap motion sensors are used in this work to cover areas with different size. Data fusion between multiple leap motion sensors can be considered as another novel contribution of this thesis work. To achieve this goal data from multiple sensors are combined. This system can improve the lack of accuracy in order to creating a practical industrial application. By fusion of several sensors in order to achieve accuracies that allow implementation in practice, a motion tracking system with higher accuracy is created.
269

Latency and Distortion compensation in Augmented Environments using Electromagnetic trackers

Himberg, Henry 17 December 2010 (has links)
Augmented reality (AR) systems are often used to superimpose virtual objects or information on a scene to improve situational awareness. Delays in the display system or inaccurate registration of objects destroy the sense of immersion a user experiences when using AR systems. AC electromagnetic trackers are ideally for these applications when combined with head orientation prediction to compensate for display system delays. Unfortunately, these trackers do not perform well in environments that contain conductive or ferrous materials due to magnetic field distortion without expensive calibration techniques. In our work we focus on both the prediction and distortion compensation aspects of this application, developing a “small footprint” predictive filter for display lag compensation and a simplified calibration system for AC magnetic trackers. In the first phase of our study we presented a novel method of tracking angular head velocity from quaternion orientation using an Extended Kalman Filter in both single model (DQEKF) and multiple model (MMDQ) implementations. In the second phase of our work we have developed a new method of mapping the magnetic field generated by the tracker without high precision measurement equipment. This method uses simple fixtures with multiple sensors in a rigid geometry to collect magnetic field data in the tracking volume. We have developed a new algorithm to process the collected data and generate a map of the magnetic field distortion that can be used to compensation distorted measurement data.
270

Subjective Evaluation of Marker-Based and Marker-Less AR for an Exhibition of a Digitally Recreated Swedish Warship

Stridbar, Lucas, Henriksson, Emma January 2019 (has links)
Background: In recent years, research in the field of Augmented Reality (AR) in cultural heritage has been rapidly expanding, due to the advancement of technology and availability of cheaper “off the shelf” hardware. It is, amongst other things, being used as a means to increase availability and regain the public’s interest in cultural heritage.Objectives: This study compares marker-based and marker-less AR in perceived usability and perceived performance through a user study. Methods: With the use of the software Unity3D and Vuforia, two AR applications were implemented. Both applications display a model of an 18th-century Swedish warship, based on a wooden ship model, each using one of the two AR methods. The digital model was remade in Autodesk Maya, to suit the needs of an AR application used on mobile devices. The applications were evaluated in a user study with 14 participants. Each participant was asked to perform a simple task of walking around the displayed ship and then answering a questionnaire on usability. This process was done for both applications, followed by a post-experiment questionnaire on perceived performance where the two methods were compared. Results: The result of the study showed that both applications were perceived as usable and well performing. The result of the usability questionnaire showed that the applications were considered usable, with an average of 90.5 points for marker-based AR and 86.8 points for marker-less AR on a 0-100 point scale. Regarding performance, the marker-based method was perceived as better performing. Conclusions: The participants felt that with just a few instructions, the applications were easy to use, even though 50% of them had no previous experience in using AR, that it could enhance a museum exhibition. Possible further development of the app would be to complete the ship-model by adding more details that are currently missing.

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