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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.
1

BEMS-assisted Commissioning of HVAC System Energy Conservation Designs

Chen, Lin-Hung 20 July 2008 (has links)
In recent years, Green Building Promotion program has made a significant progress where 1359 cases have acquired the Green Building Candidate Certificate. Among them, 245 cases or 18% in total, eventually received the Green Building Label which is considered low and need to be improved. On the other hand, in United States where LEED is applied, the Commissioning, abbreviated as Commissioning, has been deemed as a Pre-Requisite Requirement for all LEED Projects. In ASHRAE design guides, Commissioning has been defined as a procedure through testing, adjusting, and balancing, to Perform in Conformity with the Design Intent. The goals of Owners, designers, and engineering contractors can all be integrated and optimized where design intent can be fulfilled with traceable records during the Commissioning process. Though Testing, Adjusting, Balancing, and Commissioning, building energy efficiency can be upgraded where energy savings and CO2 emission reduction can be obtained.
2

Frameworks for Part Generation in Multiple CAD Systems and for CAD Simulation with Multiple Users

Sadler, Jonathan Edwin 10 December 2020 (has links)
Companies often require designers to work with and operate between different computer-aided design (CAD) systems. To interoperate between these systems, a neutral design standard for CAD models is needed that allows for generation, customization, and parameterization. Current standards often fail to incorporate file history and design intent. The research proposes a simplified, neutral design format that can be used to generate models in different CAD systems. The format proposes additional functionality not yet found in existing neutral formats or scripts. The system was tested by generating models in both NX and CATIA, then comparing the models for accuracy, flexibility, and similarity of the results. Utilizing the principles established with the neutral framework, a system was developed that facilitates a collaborative CAD modeling environment that supports the interaction of models within virtual reality (VR). A framework is presented that allows for the models to be created and then used in VR without the need for conversion. Strategies are discussed for minimizing the impacts of latency and unit testing was conducted to evaluate functionality. Furthermore, feasibility of using modern game engines such as Unity, Unreal Engine, and Godot to aid in the development of both VR and physics simulations are discussed. The above foundation and frameworks enhance collaboration in training and simulation in VR environments. This research demonstrates that by using neutral design standards, collaboration could be improved between different software, as well as between different engineers. Common strategies can be used for solving issues with conversions across the design space and integrated into future VR systems. This research will be indispensable to furthering studies of collaboration and design in remote environments.
3

Frameworks for Part Generation in Multiple CAD Systems and for CAD Simulation with Multiple Users

Sadler, Jonathan Edwin 10 December 2020 (has links)
Companies often require designers to work with and operate between different computer-aided design (CAD) systems. To interoperate between these systems, a neutral design standard for CAD models is needed that allows for generation, customization, and parameterization. Current standards often fail to incorporate file history and design intent. The research proposes a simplified, neutral design format that can be used to generate models in different CAD systems. The format proposes additional functionality not yet found in existing neutral formats or scripts. The system was tested by generating models in both NX and CATIA, then comparing the models for accuracy, flexibility, and similarity of the results. Utilizing the principles established with the neutral framework, a system was developed that facilitates a collaborative CAD modeling environment that supports the interaction of models within virtual reality (VR). A framework is presented that allows for the models to be created and then used in VR without the need for conversion. Strategies are discussed for minimizing the impacts of latency and unit testing was conducted to evaluate functionality. Furthermore, feasibility of using modern game engines such as Unity, Unreal Engine, and Godot to aid in the development of both VR and physics simulations are discussed. The above foundation and frameworks enhance collaboration in training and simulation in VR environments. This research demonstrates that by using neutral design standards, collaboration could be improved between different software, as well as between different engineers. Common strategies can be used for solving issues with conversions across the design space and integrated into future VR systems. This research will be indispensable to furthering studies of collaboration and design in remote environments.
4

ANNOTATION MECHANISMS TO MANAGE DESIGN KNOWLEDGE IN COMPLEX PARAMETRIC MODELS AND THEIR EFFECTS ON ALTERATION AND REUSABILITY

Dorribo Camba, Jorge 12 January 2015 (has links)
El proyecto de investigación propuesto se enmarca dentro del área de diseño de producto con aplicaciones de modelado sólido CAD/CAM (Computer Aided Design/Computer Aided Manufacturing). Concretamente, se pretende hacer un estudio de las herramientas de anotación asociativas disponibles en las aplicaciones comerciales de modelado CAD con el fin de analizar su uso, viabilidad, eficiencia y efectos en la modificación y reutilización de modelos digitales 3D, así como en la gestión y comunicación del conocimiento técnico vinculado al diseño. La idea principal de esta investigación doctoral es establecer un método para representar y evaluar el conocimiento implícito de los ingenieros de diseño acerca de un modelo digital, así como la integración dinámica de dicho conocimiento en el propio modelo CAD, a través de anotaciones, con el objetivo de poder almacenar y comunicar eficientemente la mayor cantidad de información útil acerca del modelo, y reducir el tiempo y esfuerzo requeridos para su alteración y/o reutilización. / Dorribo Camba, J. (2014). ANNOTATION MECHANISMS TO MANAGE DESIGN KNOWLEDGE IN COMPLEX PARAMETRIC MODELS AND THEIR EFFECTS ON ALTERATION AND REUSABILITY [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/45997 / TESIS
5

Developing Intelligent Engineering Collaboration Tools Through the use of Design Rationale

Ryskamp, Jordan David 16 September 2010 (has links) (PDF)
This thesis presents a new method that improves upon the existing approaches to developing collaborative tools. The new method uses automatically inferred and manually recorded design rationale to intelligently filter the information that is shared by a collaborative tool. This represents an improvement upon the existing state of the art in collaborative engineering tools. To demonstrate the viability of the method three collaborative tools were created. The first is a multi-user collaborative design environment tool named SimulPart and built upon the NX CAD package. SimulPart uses the new method to limit the amount of communication required to keep every user in synch during a multi-user co-design session. The second implementation is a visual history tool named VisiHistory that allows designers to watch time lapse videos of the creation of a design that are automatically generated using the new method. The final tool is an intelligent user directory named SmartHelp that uses the new method to allow designers to identify which of their peers have expertise in certain CAD operations. Validation was performed for each of these tools by benchmarking the tool against the leading commercial solution or industry process. The results of the validation showed that the new method does in fact offer a superior collaborative solution as it outperforms the existing tools and methods in several key collaborative metrics. As a result of this work future efforts are encouraged into both improving upon the quality of the inferred design rationale and increasing the functionality of the three tools created using the new method.
6

Digitisation of the splinting process : exploration and evaluation of a computer aided design approach to support additive manufacture

Paterson, Abby January 2013 (has links)
Upper extremity splinting is a popular treatment method for a range of conditions, such as rheumatoid arthritis. The intent of this treatment approach is multifaceted, but fundamentally, the provision of tools to enable and encourage patients to carry out everyday activities and to improve their quality of life is paramount. However, the aesthetic and functional limitations of wrist immobilisation splints demonstrate various weaknesses in terms of wear duration and frequency. Patient compliance is often compromised due to a number of factors, including the perceived stigma associated with assistive devices. Additive Manufacturing (AM) has proved its worth in a number of applications relating to the design of assistive devices; builds of complex, bespoke fitting geometries make AM an ideal fabrication method for upper extremity splints. However, recent advances in system technology to enable multi-material builds have been limited in this field, and a distinct need for a specialised three-dimensional (3D) Computer Aided Design (CAD) software approach is required to allow therapists to design splints for AM. Furthermore, the intent to keep practising therapists at the forefront of splint prescription is of utmost importance. This research proposes a digitised splinting approach, specifically through development of a 3D CAD software strategy to allow therapists to capture their design intent without compromising creativity. Furthermore, the approach proposes the exploration of AM build capabilities by allowing the integration of more creative features, such as aesthetically pleasing lattice structures for increased skin ventilation. The approach also proposes the integration of multiple materials to replicate and improve upon current splint design and fabrication practises. The approach therefore explores an exciting new paradigm for upper extremity splinting, the driving characteristics of which have not been proposed before as a collective medium. This research describes the feasibility of capturing therapists design intent in a 3D CAD virtual environment, whilst capturing therapists opinions of the approach with suggestions for future research and development. Results concluded that therapists were excited by the proposed transition in AM splinting, but that significant development is required elsewhere to establish a supporting infrastructure in order to make the approach a viable option in future upper extremity splinting.
7

none

Liang, Mei-Sheue 05 February 2002 (has links)
none
8

Knowledge Guided Non-Uniform Rational B-Spline (NURBS) for Supporting Design Intent in Computer Aided Design (CAD) Modeling

Rajab, Khairan 01 January 2011 (has links)
For many years, incompatible computer-aided design (CAD) packages that are based on Non-uniform Rational B-Spline (NURBS) technology carried out the exchange of models and data through either neutral file formats (IGES or STEP) or proprietary formats that have been accepted as quasi industry standards. Although it is the only available solution at the current time, the exchange process most often produces unsatisfactory results. Models that are impeccable in the original modeling system usually end up with gaps or intersections between surfaces on another incompatible system. Issues such as loss of information, change of data accuracy, inconsistent tolerance, and misinterpretation of the original design intent are a few examples of problems associated with migrating models between different CAD systems. While these issues and drawbacks are well known and cost the industry billions of dollars every year, a solution to eradicate problems from their sources has not been developed. Meanwhile, researchers along with the industries concerned with these issues have been trying to resolve such problems by finding means to repair the migrated models either manually or by using specialized software. Designing in recent years is becoming more knowledge intensive and it is essential for NURBS to take its share of the ever increasing use of knowledge. NURBS are very powerful modeling tools and have become the de facto standard in modeling. If we stretch their strength and make them knowledge driven, benefits beyond current expectations can be achieved easily. This dissertation introduces knowledge guided NURBS with theoretical and practical foundations for supporting design intent capturing, retrieval, and exchange among dissimilar CAD systems. It shows that if NURBS entities are tagged with some knowledge, we can achieve seamless data exchange, increase robustness, and have more reliable computations, all of which are ultimate objectives many researchers in the field of CAD have been trying to accomplish for decades. Establishing relationships between a NURBS entity and its origin and destinations can aid with seamless CAD model migration. The type of the NURBS entity and the awareness of any irregularities can lead to more intelligent decisions on how to proceed with many computations to increase robustness and achieve a high level of reliability. As a result, instead of having models that are hardly modifiable because of migrating raw numerical data in isolation, the knowledge driven migration process will produce models that are editable and preserve design intent. We have addressed the issues not only theoretically but also by developing a prototype system that can serve as a test bed. The developed system shows that a click of a button can regenerate a migrated model instead of repairing it, avoiding delay and corrective processes that only limit the effective use of such models.
9

Associative CAD References in the Neutral Parametric Canonical Form

Staves, Daniel Robert 01 March 2016 (has links)
Due to the multiplicity of computer-aided engineering applications present in industry today, interoperability between programs has become increasingly important. A survey conducted among top engineering companies found that 82% of respondents reported using 3 or more CAD formats during the design process. A 1999 study by the National Institute for Standards and Technology (NIST) estimated that inadequate interoperability between the OEM and its suppliers cost the US automotive industry over $1 billion per year, with the majority spent fixing data after translations. The Neutral Parametric Canonical Form (NPCF) prototype standard developed by the NSF Center for e-Design, BYU Site offers a solution to the translation problem by storing feature data in a CAD-neutral format to offer higher-fidelity parametric transfer between CAD systems. This research has focused on expanding the definitions of the NPCF to enforce data integrity and to support associativity between features to preserved design intent through the neutralization process. The NPCF data structure schema was defined to support associativity while maintaining data integrity. Neutral definitions of new features was added including multiple types of coordinate systems, planes and axes. Previously defined neutral features were expanded to support new functionality and the software architecture was redefined to support new CAD systems. Complex models have successfully been created and exchanged by multiple people in real-time to validated the approach of preserving associativity and support for a new CAD system, PTC Creo, was added.
10

An ethnographically informed analysis of design intent communication in BIM-enabled architectural practice

Abdelmohsen, Sherif Morad Abdelkader 05 July 2011 (has links)
The building information model (BIM) is assumed to encompass all the required parameters, rules and attributes about a design product and process for Architecture-Engineering-Construction (AEC) practitioners in a way that is comprehendible by all participants sharing the model and that communicates their needs and intentions. The socio-cognitive day-to-day interactions that occur in the workplace imply however that there are discrepancies between what is exchanged as design information when sharing a model and what is exchanged as goals, needs and possibly conflicting intentions and interests when sharing a common ill-structured problem. The findings of an ethnographic study are presented. The study investigates affordances and limitations in BIM-enabled practice regarding the communication of design intent among design teams in the context of an architectural project. Grounded theory coding was used as a basis for analytic induction through constant comparison and examination of data from field observation, interviews and design meetings, to identify emergent conceptual categories central to the research inquiry. A "thick description" was provided that took into account the dynamic interactions among teams, including interdisciplinary, intradisciplinary and non-disciplinary interaction. By dissecting hypothetical models of shared project information offered by BIM, the dissertation identified interfaces of information exchange, states of the BIM model as a boundary object, and emergent and overlapping communities of practice that delineate the degree of completeness and correctness of a BIM model and describe its effectiveness in capturing and conveying the intent of participants upon interaction. To draw parallels to other contexts, the assumptions central to the study were discussed in relation to a spectrum of possible scenarios within the larger population of AEC firms. In light of the findings and "persona" descriptions identified in the study, the dissertation examined and proposed amendments and richer descriptions to existing surveys and market reports that address the use and benefits of BIM in the AEC industry, including topics such as the internal business value of BIM, top ways to improve value of BIM, and impact of project factors on BIM value.

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