Browsing by Subject "design"
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Item An Exploration of Multi-touch Interaction Techniques(2013-08-16) Damaraju Sriranga, Sashikanth RajuResearch in multi-touch interaction has typically been focused on direct spatial manipulation; techniques have been created to result in the most intuitive mapping between the movement of the hand and the resultant change in the virtual object. As we attempt to design for more complex operations, the effectiveness of spatial manipulation as a metaphor becomes weak. We introduce two new platforms for multi-touch computing: a gesture recognition system, and a new interaction technique. I present Multi-Tap Sliders, a new interaction technique for operation in what we call non-spatial parametric spaces. Such spaces do not have an obvious literal spatial representation, (Eg.: exposure, brightness, contrast and saturation for image editing). The multi-tap sliders encourage the user to keep her visual focus on the tar- get, instead of requiring her to look back at the interface. My research emphasizes ergonomics, clear visual design, and fluid transition between modes of operation. Through a series of iterations, I develop a new technique for quickly selecting and adjusting multiple numerical parameters. Evaluations of multi-tap sliders show improvements over traditional sliders. To facilitate further research on multi-touch gestural interaction, I developed mGestr: a training and recognition system using hidden Markov models for designing a multi-touch gesture set. Our evaluation shows successful recognition rates of up to 95%. The recognition framework is packaged into a service for easy integration with existing applications.Item Analysis and Design of Smart PV Module(2012-12-10) Mazumdar, PoornimaThis thesis explores the design of a smart photovoltaic (PV) module- a PV module in which PV cells in close proximity are electrically grouped to form a pixel and are connected to dc-dc converter blocks which reside embedded in the back pane of the module. An auto-connected flyback converter topology processing less than full power is used to provide high gain and perform maximum power point tracking (MPPT). These dc-dc converters interface with cascaded H-bridge inverter modules operating on feed forward control for dc-link voltage ripple rejection. By means of feed forward control, a significant reduction in dc link capacitance is achieved by enduring higher dc link ripple voltages. The dc link electrolytic capacitors are replaced with film capacitors thus offering an improvement in the reliability of the smart PV module. The proposed configuration is capable of producing 120V/ 240V AC voltage. The PV module now becomes a smart AC module by virtue of embedded intelligence to selectively actuate the individual dc-dc converters and control the output AC voltages directly, thus becoming a true plug and power energy system. Such a concept is ideal for curved surfaces such as building integrated PV (BIPV) system applications where gradients of insolation and temperature cause not only variations from PV module-to-PV module but from group-to-group of cells within the module itself. A detailed analysis along with simulation and experimental results confirm the feasibility of the proposed system.Item Content-aware Caching and Traffic Management in Content Distribution Networks(2012-02-14) Amble, Meghana MukundThe rapid increase of content delivery over the Internet has lead to the proliferation of content distribution networks (CDNs). Management of CDNs requires algorithms for request routing, content placement, and eviction in such a way that user delays are small. Our objective in this work is to design feasible algorithms that solve this trio of problems. We abstract the system of front-end source nodes and back-end caches of the CDN in the likeness of the input and output nodes of a switch. In this model, queues of requests for different pieces of content build up at the source nodes, which route these requests to a cache that contains the content. For each request that is routed to a cache, a corresponding data file is transmitted back to the source across links of finite capacity. Caches are of finite size, and the content of the caches can be refreshed periodically. A requested but missing item is fetched to the cache from the media vault of the CDN. In case of a lack of adequate space at the cache, an existing, unrequested item may be evicted from the cache in order to accommodate a new item. Every such cache refresh or media vault access incurs a finite cost. Hence the refresh periodicity allowed to the system represents our system cost. In order to obtain small user delays, our algorithms must consider the lengths of the request queues that build up at the nodes. Stable policies ensure the finiteness of the request queues, while good polices also lead to short queue lengths. We first design a throughput-optimal algorithm that solves the routing-placement eviction problem using instantaneous system state information. The design yields insight into the impact of different cache refresh and eviction policies on queue length. We use this and construct throughput optimal algorithms that engender short queue lengths. We then propose a regime of algorithms which remedies the inherent problem of wastage of capacity. We also develop heuristic variants, and we study their performance. We illustrate the potential of our approach and validate all our claims and results through simulations on different CDN topologies.Item Design exploration: engaging a larger user population(2009-06-02) Moore, John MichaelSoftware designers must understand the domain, work practices, and user expectations before determining requirements or generating initial design mock-ups. Users and other stakeholders are a valuable source of information leading to that understanding. Much work has focused on design approaches that include users in the software development process. These approaches vary from surveys and questionnaires that garner responses from a population of potential users to participatory design processes where representative users are included in the design/development team. The Design Exploration approach retains the remote and asynchronous communication of surveys while making expression of feedback easier by providing users alternatives to textual communication for their suggestions and tacit understanding of the domain. To do this, visual and textual modes of expression are combined to facilitate communication from users to designers while allowing a broad user audience to contribute to software design. One challenge to such an approach is how software designers make use of the potentially overwhelming combination of text, graphics, and other content. The Design Exploration process provides users and other stakeholders the Design Exploration Builder, a construction kit where they create annotated partial designs. The Design Exploration Analyzer is an exploration tool that allows software designers to consolidate and explore partial designs. The Analyzer looks for patterns based on textual analysis of annotations and spatial analysis of graphical designs, to help identify interesting examples and patterns within the collection. Then software designers can use this tool to search and browse within the exploration set in order to better understand the task domain, user expectations and work practices. Evaluation of the tools has shown that users will often work to overcome expression constraints to convey information. Moreover, the mode of expression influences the types of information garnered. Furthermore, including more users results in greater coverage of the information gathered. These results provide evidence that Design Exploration is an approach that collects software and domain information from a large group of users that lies somewhere between questionnaires and face to face methods.Item Design guidelines and evaluation of an ergonomic chair feature capable of providing support to forward-leaning postures(Texas A&M University, 2005-02-17) Stevens, Edward MartinThis research investigated the need, design, and evaluation of a product capable of providing support to forward-leaning postures. Due to the high occurrence of low-back pain in industry potentially due to workers performing their tasks while assuming forward-leaning postures, along with the biological plausibility of these postures causing low-back pain, the need was established for a product that provides forward-leaning support. An envelope was quantified, ranging from the 5th percentile female to the 95th percentile male, to establish the range of potential forward-leaning postures. The design of a Support-Arm for use with current ergonomic chairs was discussed and design feature specifications were then provided. A Latin Square statistical design was employed to evaluate a Support-Arm model alongside 8 other commonly used chairs over 3 different postures. Subjects, overall, had lower peak pressures for the buttock-thigh region, increased productivity, higher comfort levels, and higher buttock-thigh contact areas when seated in the Support-Arm model chair as compared to the other chairs. Subjects, overall, also ranked this chair first over the other chairs for preferred use after having sitting experience in all 9 chairs. In an additional part of the evaluation, subjects chose their own set-up of the Support-Arm model chair. Eleven of the 18 subjects chose to use the Support-Arm when their workstation was located 36? above the floor. Subjects confirmed the need to design a Support-Arm capable of providing forward leaning support to the entire envelope of forward-leaning postures. Statistical evaluation revealed several significant differences between the chairs. The results gave no indication that the use of a Support-Arm for forward-leaning support may cause detrimental effects to users or overall chair ergonomics. Future research could track workers? use of a Support-Arm in industry and compare their occurrence of low-back pain to a control group.Item Design manual for excavation support using deep mixing technology(Texas A&M University, 2005-02-17) Rutherford, Cassandra JanelDeep mixing (DM) is the modification of in situ soil to increase strength, control deformation, and reduce permeability. Multi?axis augers and mixing paddles are used to construct overlapping columns strengthened by mixing cement with in situ soils. This method has been used for excavation support to increase bearing capacity, reduce movements, prevent sliding failure, control seepage by acting as a cut?off barrier, and as a measure against base heave. DM is effectively used in excavations both in conjunction with and in substitution of traditional techniques, where it results in more economical and convenient solutions for the stability of the system and the prevention of seepage. Although DM is currently used for excavation control in numerous projects, no standard procedure has been developed and the different applications have not been evaluated. As this technique emerges as a more economical and effective alternative to traditional excavation shoring, there is a need for guidelines describing proven procedures for evaluation of design, analysis and construction. The main objective of this research is to develop a methodology to design retaining systems using deep mixing technology. The method will be evaluated using numerical analysis of one selected case history.Item Design with Uncertain Technology Evolution(2012-10-19) Arendt, Jonathan LeeDesign is an uncertain human activity involving decisions with uncertain outcomes. Sources of uncertainty in product design include uncertainty in modeling methods, market preferences, and performance levels of subsystem technologies, among many others. The performance of a technology evolves over time exhibiting improving performance as research and development efforts continue. As the performance of a technology in the future is uncertain, quantifying the evolution of these technologies poses a challenge in making design decisions. Designing systems involving evolving technologies is a poorly understood problem. The objective of this research is to create a computational method allowing designers to make decisions encompassing the evolution of technology. Techniques for modeling evolution of a technology that has multiple performance attributes are developed. An S-curve technology evolution model is used. The performance of a technology develops slowly at first, quickly during heavy R&D effort, and slowly again as the performance approaches its limits. Pareto frontiers represent the set of optimal solutions that the decision maker can select from. As the performance of a technology develops, the Pareto frontier shifts to a new location. The assumed S-curve form of technology development allows the designer to apply the uncertainty of technology development directly to the S-curve evolution model rather than applying the uncertainty to the performance, giving a more focused application of uncertainty in the problem. Monte Carlo simulations are used to the propagate uncertainty through the decision. The decision-making methods give designers greater insight when making long-term decisions regarding evolving technologies. The scenario of an automotive manufacturing firm entering the electric vehicle market deciding which battery technology to include in their new line of electric cars is used to demonstrate the decision-making method. Another scenario of a wind turbine energy company deciding which technology to invest in demonstrates a more sophisticated technology evolution modeling technique and the decision making under uncertainty method.Item Developing a Framework for a New Visual-Based Interface Design in Autodesk Maya(2012-10-19) Withers, Timothy ClaytonIn this thesis, I develop an efficient and user-friendly node-based interface to be used in the creation of a particle system in Autodesk Maya. Maya's interface inconsistencies were identified and solutions were designed based on research in a number of fields related to human-computer interaction (HCI) as well as taking design queues from other highly successful 3D programs that employ a node-based interface. This research was used to guide the design of the interface in terms of organizing the data into logical chunks of information, using color to help the user develop working mental models of the system, and also using simple, easy to identify, graphical representations of a particle system. The result is an easy-to-use and intuitive interface that uses a visual-based approach in creating a particle system in Maya. By following guidelines laid out by previous researchers in the field of HCI, the interface should be a less frustrating to use and more organized version of Maya's current interface.Item Dreamhome: A Personal Space of Core Human Desire and Ambition(2012-08-15) Tanna, Hemali 1980-Dreamhome is a creative exploration of a prototype house designed with creative freedom using possible future technologies that may not be currently feasible. New and forthcoming technology in various scientific branches that could be applicable to architecture will be presented, and the applications discussed. Limitations of application to architecture of the reviewed technologies will be discussed. Prior works by architects and engineers who push boundaries to innovatively overcome technological limitations will be explored, as will examples in which advanced technology is applied to create unique architectural designs. Together these references will evoke inspirations to be translated into an architectural design and a virtual home. The house is desired to boast of a unique design with various aesthetic and functional features that are not usually seen in present day architecture. This visualization could be a glimpse of possible home design of the future.Item Hands as characters: designing for a large scale pipeline using limited characteristics(Texas A&M University, 2007-09-17) Chance, Franklin S., IVThis thesis concentrates on hands and their production as concerns a larger-scale pipeline with multiple secondary or tertiary characters. It establishes a platform from which many unique hands can be produced from a single, rigged hand. Emphasis is given to automating a large amount of the rigging and sculpting processes through use of high and low-level user interfaces so users of varying skill can use this thesis effectively. Systems for sculpting the hand and animating the hand are created for their own specific purposes and linked together through the interface to create a tool for modeling a new hand from an existing mesh, having the new hand automatically rigged for animation and ready to use with only minor adjustments by the user. A system is developed conclusively that allows for the efficient mass production of tertiary character assets. Unique hands are quickly and correctly created with the ability to connect them to digital characters. This method can be applied not only to hands, but other parts of characters as well. Eventually full secondary or tertiary characters can be created using this method of production.Item Healing design: a phenomenological approach to the relation of the physical setting to positive social interaction in pediatric intensive care units in the United States and Turkey(Texas A&M University, 2006-04-12) Ozcan, HilalThis study examines the impact of the physical setting in the care and healing process of hospitalized children, their families, and the caregivers in two selected pediatric intensive care units (PICUs) in the U.S. and Turkey. A holistic, cross-cultural, comparative, and naturalistic approach emphasized the importance of the total (i.e., physical, social, cultural, spiritual, organizational, political) environment and quality of life to health and healing. Information was gathered through qualitative methods such as participant observations, behavioral maps, in-depth interviews, and floor plan analysis. Despite some universal features of the PICU atmosphere, the value and place ascribed to pediatric critical care in Turkey and the U.S. present different worldviews. Field studies revealed social interaction as a universal healing function despite its cultural specificity stemming from socio-cultural, ethnic, economic, and religious differences between different groups. Crowding, parental absence, and over-stimulation, which stem from the lack of individual patient rooms, and organizational problems related with human resources and staffing shortage play against the critically ill child??s deep need to heal in the Turkish PICU. Despite spatial limitations, informal social interactions and cooperative relationships among caregivers, their devotion, and their ability to adapt to the existing physical and social environment enable care delivery. While staffing shortage continues to be a crucial problem in the U.S. model, specialization of labor and the systemic organization in general support care delivery, reducing the importance of informal social interactions and cooperation among caregivers. However, emphasizing the role of the family in the child??s care, social interaction is also identified as a healing function in this setting. Therefore, despite the significant role the physical setting may play in healing, social interaction is found to be more important for improving patient outcomes and the well-being of families and caregivers. The study focuses on six healing design interventions to increase the chances for positive social interaction and collaboration. These are programmatic (provisional, scale, locational), functional, ambient, symbolic, social and psychological interventions.Item Material and processes selection in conceptual design(Texas A&M University, 2005-02-17) Krishnakumar, KarthikeyanMaterials and manufacturing processes are an integral part of the design of a product. The need to combine materials and manufacturing processes selection during the early stages of the design has previously been realized. The work that generally attracts the most attention is by M.F. Ashby. This methodology, like others, concentrates on materials and manufacturing processes selection after the conceptual design is completed and before moving into embodiment design. The disadvantage of waiting until the conceptual design is completed to address materials and manufacturing processes is that the designer cannot search for conceptual solutions when dealing with issues relating to the materials and manufacturing processes domains. By not considering these issues early on in the design process, the scope for innovation is reduced and this results in the designer being fixated on the configuration at hand. It is well recognized that this is not the best way to address a design challenge and an even worse approach to innovation. The basic framework for which enhancements and improvements are suggested is the design methodology practiced and taught by the members of the Institute for Innovation and Design in Engineering (IIDE) at Texas A&M University. Conceptual design is very much a part of the IIDE design process; but the current format concentrates on functional parameters and how to search for conceptual solutions for these, and does not highlight materials and manufacturing issues in the preliminary design stages where it could be most helpful. The work documented in this thesis is an attempt to ensure that there is no disconnect between function oriented design and the materials and manufacturing processes that are applicable to that design. The core of the thesis is to incorporate a thought process which will help the designer during conceptual design phase to: 1. Consciously question if there materials and manufacturing issues; 2. Identify critical parameters in both of these domains; and 3. Search for conceptual solutions to these identified critical parameters.Item Optimal dimensionless design and analysis of jet ejectors as compressors and thrust augmenters(Texas A&M University, 2006-08-16) Mohan, GaneshA jet ejector may be used as a compressor or to enhance thrust of watercraft or aircraft. Optimization of jet ejectors as compressors and thrust augmenters was conducted using the software GAMBIT (Computer Aided Engineering (CAE) tool for geometry and mesh generation) and FLUENT (Computational Fluid Dynamics (CFD) solver kit). Scripting languages PYTHON and SCHEME were used to automate this process. The CFD model employed 2D axis symmetric, steady-state flow using the ??k method (including wall functions) to model turbulence. Initially, non-dimensionalization of the jet ejector as a gas compressor was performed with respect to scale, fluid, and operating pressure. Surprisingly, rather than the conventional parameters like Mach or Re number, the results showed a completely new parameter (christenedGM- Gauge Mach) that when kept constant will result in non-dimensionalization. Non-dimensionalization of a jet ejector for watercraft propulsion was conducted using 2D axis symmetric, steady-state flow modeling using the ??kmethod (including wall functions). It showed consistent results for the same velocity ratio (r) of nozzle velocity to free-stream velocity for different scales, fluids, and ambient pressures.Item Optimal fracture treatment design for dry gas wells maximizes well performance in the presence of non-Darcy flow effects(Texas A&M University, 2004-11-15) Lopez Hernandez, Henry De JesusThis thesis presents a methodology based on Proppant Number approach for optimal fracture treatment design of natural gas wells considering non-Darcy flow effects in the design process. Closure stress is taken into account, by default, because it is the first factor decreasing propped pack permeability at in-situ conditions. Gel damage was also considered in order to evaluate the impact of incorporating more damaging factors on ultimate well performance and optimal geometry. Effective fracture permeability and optimal fracture geometry are calculated through an iterative process. This approach was implemented in a spreadsheet. Non-Darcy flow is described by the ? factor. All ? factor correlations available in the literature were evaluated. It is recommended to use the correlation developed specifically for the given type of proppant and mesh size, if available. Otherwise, the Pursell et al. or the Martins et al. equations are recommended as across the board reliable correlations for predicting non-Darcy flow effects in the propped pack. The proposed methodology was implemented in the design of 11 fracture treatments of 3 natural tight gas wells in South Texas. Results show that optimal fracture design might increase expected production in 9.64 MMscf with respect to design that assumes Darcy flow through the propped pack. The basic finding is that for a given amount of proppant shorter and wider fractures compensate the non-Darcy and/or gel damage effect. Dynamic programming technique was implemented in design of multistage fractures for one of the wells under study for maximizing total gas production. Results show it is a powerful and simple technique for this application. It is recommended to expand its use in multistage fracture designs.Item Structural Thermomechanical Models for Shape Memory Alloy Components(2014-04-18) Rao, AshwinThermally responsive shape memory alloys (SMA) demonstrate interesting properties like shape memory effect (SME) and superelasticity (SE). SMA components in the form of wires, springs and beams typically exhibit complex, nonlinear hysteretic responses and are subjected to tension, torsion or bending loading conditions. Traditionally, simple strength of materials based models/tools have driven engineering designs for centuries, even as more sophisticated models existed for design with conventional materials. In light of this, an effort to develop strength of materials type modeling approach that can capture complex hysteretic SMA responses under different loading conditions is undertaken. The key idea here is of separating the thermoelastic and the dissipative part of the hysteretic response by using a Gibbs potential and thermodynamic principles. The dissipative part of the response is later accounted for by a discrete Preisach model. The models are constructed using experimentally measurable quantities (like torque?twist, bending moment?curvature etc.), since the SMA components subjected to torsion and bending experience an in-homogeneous non-linear stress distribution across the specimen cross-section. Such an approach enables simulation of complex temperature dependent superelastic responses including those with multiple internal loops. The second aspect of this work deals with the durability of the material which is of critical importance with increasing use of SMA components in different engineering applications. Conventional S-N curves, Goodman diagrams etc. that capture only the mechanical loading aspects are not adequate to capture complex thermomechanical coupling seen in SMAs. Hence, a novel concept of driving force amplitude v/s number of cycles equivalent to thermodynamical driving force for onset of phase transformations is proposed which simultaneously captures both mechanical and thermal loading in a single framework. Recognizing the paucity of experimental data on functional degradation of SMAs (especially SMA springs), a custom designed thermomechanical fatigue test rig is used to perform user defined repeated thermomechanical tests on SMA springs. The data from these tests serve both to calibrate the model and establish thermodynamic driving force and extent of phase transformation relationships for SMA springs. A drop in driving force amplitude would suggest material losing its ability to undergo phase transformations which directly corresponds to a loss in the functionality/smartness of SMA component. This would allow designers to set appropriate driving force thresholds as a guideline for analyzing functional life of SMA components.Item Technology Characterization Models and Their Use in Designing Complex Systems(2011-08-08) Parker, Robert ReedWhen systems designers are making decisions about which components or technologies to select for a design, they often use experience or intuition to select one technology over another. Additionally, developers of new technologies rarely provide more information about their inventions than discrete data points attained in testing, usually in a laboratory. This makes it difficult for system designers to select newer technologies in favor of proven ones. They lack the knowledge about these new technologies to consider them equally with existing technologies. Prior research suggests that set-based design representations can be useful for facilitating collaboration among engineers in a design project, both within and across organizational boundaries. However, existing set-based methods are limited in terms of how the sets are constructed and in terms of the representational capability of the sets. The goal of this research is to introduce and demonstrate new, more general set-based design methods that are effective for characterizing and comparing competing technologies in a utility-based decision framework. To demonstrate the new methods and compare their relative strengths and weaknesses, different technologies for a power plant condenser are compared. The capabilities of different condenser technologies are characterized in terms of sets defined over the space of common condenser attributes (cross sectional area, heat exchange effectiveness, pressure drop, etc.). It is shown that systems designers can use the resulting sets to explore the space of possible condenser designs quickly and effectively. It is expected that this technique will be a useful tool for system designers to evaluate new technologies and compare them to existing ones, while also encouraging the use of new technologies by providing a more accurate representation of their capabilities. I compare four representational methods by measuring the solution accuracy (compared to a more comprehensive optimization procedure's solution), computation time, and scalability (how a model changes with different data sizes). My results demonstrate that a support vector domain description-based method provides the best combination of these traits for this example. When combined with recent research on reducing its computation time, this method becomes even more favorable.