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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.
141

Biomimetic Visual Navigation Architectures for Autonomous Intelligent Systems

Pant, Vivek January 2007 (has links)
Intelligent systems with even the bare minimum of sophistication require extensive computational power and complex processing units. At the same time, small insects like flies are adept at visual navigation, target pursuit, motionless hovering flight, and obstacle avoidance. Thus, biology provides engineers with an unconventional approach to solve complicated engineering design problems. Computational models of the neuronal architecture of the insect brain can provide algorithms for the development of software and hardware to accomplish sophisticated visual navigation tasks. In this research, we investigate biologically-inspired collision avoidance models primarily based on visual motion. We first present a comparative analysis of two leading collision avoidance models hypothesized in the insect brain. The models are simulated and mathematically analyzed for collision and non-collision scenarios. Based on this analysis it is proposed that along with the motion information, an estimate of distance from the obstacle is also required to reliably avoid collisions. We present models with tracking capability as solutions to this problem and show that tracking indirectly computes a measure of distance. We present a camera-based implementation of the collision avoidance models with tracking. The camera-based system was tested for collision and non-collision scenarios to verify our simulation claims that tracking improves collision avoidance. Next, we present a direct approach to estimate the distance from an obstacle by utilizing non-directional speed. We describe two simplified non-directional speed estimation models: the non-directional multiplication (ND-M) sensor, and the non-directional summation (ND-S) sensor. We also analyze the mathematical basis of their speed sensitivity. An analog VLSI chip was designed and fabricated to implement these models in silicon. The chip was fabricated in a 0.18 um process and its characterization results are reported here. As future work, the tracking algorithm and the collision avoidance models may be implemented as a sensor chip and used for autonomous navigation by intelligent systems.
142

Supporting the Use of Causally Related Functions in Biomimetic Design

Cheong, Hyunmin 07 January 2014 (has links)
Biomimetic design uses biological analogies to produce innovative engineering solutions. However, designers face challenges in identifying useful biological analogies and correctly applying the analogies identified to design solutions. To overcome these challenges, this thesis proposes the use of causally related functions in biomimetic design. Causally related functions describe how a desired function is enabled by another function. To support the use of causally related functions, a set of tools was developed. First, the causal relation template and mapping techniques (one-to-one mapping instructions and problem-independent scenario mapping) were devised to assist designers to identify and apply causally related functions from descriptions of biological phenomena. In pen-and-paper experiments with senior undergraduate engineering students, the causal relation template, if used correctly, facilitated the development of design concepts that were analogous to biological phenomena provided as sources of analogy. In addition, the mapping techniques reduced the percentage of participants who made non-analogous associations from biological phenomena to develop design concepts. Another tool developed was the causal relation retrieval method. The method uses syntactic information in natural language sentences to explicitly identify causally related functions. A modified verbal protocol study with graduate engineering students revealed that the retrieval method increased the likelihood of locating biological phenomena relevant to given design problems compared to a single verb-keyword search method. Also, the search matches located with the retrieval method were more likely to facilitate functional association to develop design concepts. These results demonstrate that the knowledge structure of causally related functions can support both the identification of relevant biological phenomena in natural language text and use of analogical reasoning between the biological phenomena and design solutions. The causal relation template and mapping strategies developed contribute to the field of biomimetic design as training methods for designers; and the causal relation retrieval method could serve a technique to bridge the gap between the natural language approach and the modeling approach to biomimetic design.
143

Supporting the Use of Causally Related Functions in Biomimetic Design

Cheong, Hyunmin 07 January 2014 (has links)
Biomimetic design uses biological analogies to produce innovative engineering solutions. However, designers face challenges in identifying useful biological analogies and correctly applying the analogies identified to design solutions. To overcome these challenges, this thesis proposes the use of causally related functions in biomimetic design. Causally related functions describe how a desired function is enabled by another function. To support the use of causally related functions, a set of tools was developed. First, the causal relation template and mapping techniques (one-to-one mapping instructions and problem-independent scenario mapping) were devised to assist designers to identify and apply causally related functions from descriptions of biological phenomena. In pen-and-paper experiments with senior undergraduate engineering students, the causal relation template, if used correctly, facilitated the development of design concepts that were analogous to biological phenomena provided as sources of analogy. In addition, the mapping techniques reduced the percentage of participants who made non-analogous associations from biological phenomena to develop design concepts. Another tool developed was the causal relation retrieval method. The method uses syntactic information in natural language sentences to explicitly identify causally related functions. A modified verbal protocol study with graduate engineering students revealed that the retrieval method increased the likelihood of locating biological phenomena relevant to given design problems compared to a single verb-keyword search method. Also, the search matches located with the retrieval method were more likely to facilitate functional association to develop design concepts. These results demonstrate that the knowledge structure of causally related functions can support both the identification of relevant biological phenomena in natural language text and use of analogical reasoning between the biological phenomena and design solutions. The causal relation template and mapping strategies developed contribute to the field of biomimetic design as training methods for designers; and the causal relation retrieval method could serve a technique to bridge the gap between the natural language approach and the modeling approach to biomimetic design.
144

The Effect of Natural Language Processing in Bioinspired Design

Burns, Madison Suzann 1987- 14 March 2013 (has links)
Bioinspired design methods are a new and evolving collection of techniques used to extract biological principles from nature to solve engineering problems. The application of bioinspired design methods is typically confined to existing problems encountered in new product design or redesign. A primary goal of this research is to utilize existing bioinspired design methods to solve a complex engineering problem to examine the versatility of the method in solving new problems. Here, current bioinspired design methods are applied to seek a biologically inspired solution to geoengineering. Bioinspired solutions developed in the case study include droplet density shields, phosphorescent mineral injection, and reflective orbiting satellites. The success of the methods in the case study indicates that bioinspired design methods have the potential to solve new problems and provide a platform of innovation for old problems. A secondary goal of this research is to help engineers use bioinspired design methods more efficiently by reducing post-processing time and eliminating the need for extensive knowledge of biological terminology by applying natural language processing techniques. Using the complex problem of geoengineering, a hypothesis is developed that asserts the usefulness of nouns in creating higher quality solutions. A designation is made between the types of nouns in a sentence, primary and spatial, and the hypothesis is refined to state that primary nouns are the most influential part of speech in providing biological inspiration for high quality ideas. Through three design experiments, the author determines that engineers are more likely to develop a higher quality solution using the primary noun in a given passage of biological text. The identification of primary nouns through part of speech tagging will provide engineers an analogous biological system without extensive analysis of the results. The use of noun identification to improve the efficiency of bioinspired design method applications is a new concept and is the primary contribution of this research.
145

Movement and Force Measurement Systems as a Foundation for Biomimetic Research on Insects

Mills, Clayton Harry January 2008 (has links)
During the undertaken research and development, two major systems were designed. These were; a prototype force sensor, and a movement measurement system. Both the developed systems were designed for the intended field of insect research, but were developed using very different underlying principles. The force measurement system uses the piezo-electric effect induced in piezo-electric bimorph elements to produce a measure of force exerted on the sensor. The movement measurement system on the other hand uses computer vision (CV) techniques to find and track the three dimensional (3D) position of markers on the insect, and thereby record the pose of the insect. To further increase the usefulness of the two measurement systems, a prototype graphical user interface (GUI) was produced to encapsulate the functionality of the systems and provide an end user with a more complete and functional research tool. The GUI allows a user to easily define the parameters required for the CV operations and presents the results of these operations to the user in an easily understood visual format. The GUI is also intended to display force measurements in a graphical means to make them easily interpreted. The GUI has been named Weta Evaluation Tracking and Analysis (WETA). Testing on the developed prototype force sensor shows that the piezo-electric bimorph elements provide an adequate measure of force exerted on them, when the voltage signal produced by an element is integrated. Furthermore, the testing showed that the developed force sensor layout produces an adequate measure of forces in the two horizontal linear degrees of freedom (DOF), but the prototype did not produce a good measure of forces in the vertical linear DOF. Development and testing of the movement measurement system showed that stereo vision techniques have the ability to produce accurate measurements of 3D position using two cameras. Although, when testing these techniques with one of the cameras replaced by a mirror, the system produced less than satisfactory results. Further testing on the feature detection and tracking portions of the movement system showed that even though these systems were implemented in a relatively simple way, they were still adequate in their associated operations. However, it was found that with some simple changes in colour spaces used during feature detection, the performance of the feature detection system in varying illumination was greatly improved. The tracking system on the other hand, operated adequately using just its associated basic principles. During the development of both prototype measurement systems, a number of conclusions were formulated that indicated areas of future development. These areas include; advanced force sensor configurations, force sensor miniaturisation, design of a force plate, improvement of feature detection and tracking, and refining of the stereo vision equipment.
146

The Development and Biocompatibility of Low Temperature Co-Fired Ceramic (LTCC) for Microfluidic and Biosensor Applications

Luo, Jin 01 January 2014 (has links)
Low temperature co-fired ceramic (LTCC) electronic packaging materials are applied for their electrical and mechanical properties, high reliability, chemical stability and ease of fabrication. Three dimensional features can also be prepared allowing integration of microfluidic channels and cavities inside LTCC modules. Mechanical, optical, electrical, microfluidic functions have been realized in single LTCC modules. For these reasons LTCC is attractive for biomedical microfluidics and Lab-on-a-Chip systems. However, commercial LTCC systems, optimized for microelectrics applications, have unknown cytocompatibility, and are not compatible with common surface functionalization chemistries. The first goal of this work is to develop biocompatible LTCC materials for biomedical applications. In the current work, two different biocompatible LTCC substrate materials are conceived, formulated and evaluated. Both materials are based from well-known and widely utilized biocompatible materials. The biocompatibilities of the developed LTCC materials for in-vitro applications are studied by cytotoxicity assays, including culturing endothelial cells (EC) both in LTCC leachate and directly on the LTCC substrates. The results demonstrate the developed LTCC materials are biocompatible for in-vitro biological applications involving EC. The second goal of this work is to develop functional capabilities in LTCC microfluidic systems suitable for in-vitro and biomedical applications. One proposed application is the evaluation of oxygen tension and oxidative stress in perfusion cell culture and bioreactors. A Clark-type oxygen sensor is successfully integrated with LTCC technique in this work. In the current work, a solid state proton conductive electrolyte is used to integrate an oxygen sensor into the LTCC. The measurement of oxygen concentration in Clark-type oxygen sensor is based on the electrochemical reaction between working electrode and counter electrode. Cyclic voltammetry and chronoamperometry are measured to determine the electrochemical properties of oxygen reduction in the LTCC based oxygen sensor. The reduction current showed a linear relationship with oxygen concentration. In addition, LTCC sensor exhibits rapid response and sensitivity in the physiological range 1─9 mg/L. The fabricated devices have the capabilities to regulate oxygen supply and determination of local dissolved oxygen concentration in the proposed applications including perfusion cell culture and biological assays.
147

NANOMETER-SCALE MEMBRANE ELECTRODE SYSTEMS FOR ACTIVE PROTEIN SEPARATION, ENZYME IMMOBILIZATION AND CELLULAR ELECTROPORATION

Chen, Zhiqiang 01 January 2014 (has links)
Automated and continuous processes are the future trends in downstream protein purification. A functionalized nanometer-scale membrane electrode system, mimicking the function of cell wall transporters, can selectively capture genetically modified proteins and subsequently pump them through the system under programmed voltage pulses. Numerical study of the two-step pulse pumping cycles coupled with experimental His-GFP releasing study reveals the optimal 14s/1s pumping/repel pulse pumping condition at 10 mM bulk imidazole concentration in the permeate side. A separation factor for GFP: BSA of 9.7 was achieved with observed GFP electrophoretic mobility of 3.1×10-6 cm2 s-1 V-1 at 10 mM bulk imidazole concentration and 14 s/1 s pumping/repel duration. The purification of His6-OleD Loki variant directly from crude E. coli extracts expression broth was demonstrated using the pulse pumping process, simplifying the separation process as well as reducing biopharmaceutical production costs. The enzymatic reactions showed that His6-OleD Loki was still active after purification. A nanoporous membrane/electrode system with directed flow carrying reagents to sequentially attached enzymes to mimic nature’s enzymes-complex system was demonstrated. The substrates residence time on the immobilized enzyme can be precisely controlled by changing the pumping rate and thereby prevent a secondary hydrolysis reaction. Immobilized enzyme showed long term storage longevity with activity half-life of 50 days at 4℃ and the ability to be regenerated. One-step immobilization and purification of His-tagged OleD Loki variant directly from expression broth, yielded 98% Uridine Diphosphate glycosylation and 80% 4-methylumbelliferone glycosylation conversion efficiency for the sequential reaction. A flow-through electroporation system, based on a novel membrane/electrode design, for the delivery of membrane-impermeant molecules into Model Leukocyte cells was demonstrated. The ability to apply low voltage between two short distance electrodes contributes to high cell viability. The flow-through system can be easily scaled-up by varying the micro-fluidic channel geometry and/or the applied voltage pulse frequency. More importantly, the system allows the electrophoretical pumping of molecules from the reservoir across the membrane/electrode system to the micro-fluidic channel for transfection, which reduces large amount of reagents used.
148

The protein and peptide mediated syntheses of non-biologically-produced oxide materials

Dickerson, Matthew B. 09 July 2007 (has links)
The research detailed in this dissertation is focused on the use of biomolecules (i.e., peptides and proteins) to form non-biologically produced materials under mild reaction conditions (i.e, neutral pH, aqueous solutions, and room temperature). The peptides utilized in the studies detailed in this dissertation were identified through the screening of single crystal rutile TiO2 substrates or Ge powder with a phage-displayed peptide library. Twenty-one peptides were identified which possessed an affinity for Ge. Those peptides possessing a basic isoelectric point as well as hydroxyl- and imidazole-containing amino acid residues were found to be the most effective in precipitating amorphous germania from an alkoxide precursor. The phage-displayed peptide library screening of TiO2 substrates yielded twenty peptides. The titania formation activity of these peptides was found to correlate with the number of positive charges they carried. The titania materials generated by the library-identified and designed peptides were found to be composed of amorphous titania as well as <10 nm anatase and/or monoclinic TiO2 crystallites. Four recombinant proteins, derived from the amino acid sequences of proteins (silaffins) associated with biosilicification in diatoms, were also investigated for titania precipitation activity. The two most basic of these recombinant silaffins, rSil1L and rSilC, were able to induce the formation of titania. The titania precipitates generated by rSil1L were found to be similar to those produced by the phage-displayed library identified peptides. The second recombinant silaffin, rSilC, was found to produce hollow spheres of titania, which, following dehydration, were observed to transform into larger, solid spheres composed of radially aligned columns of rutile TiO2. The highly repetitive nature of the rSilC s amino acid sequence is believed to be responsible for the differences in TiO2 polymorph generated by the different recombinant silaffins and peptides. This dissertation also details research conducted on the formation of titania utilizing rSilC conjugated to synthetic and biogenic silica surfaces. These silica surfaces were functionalized with a newly developed drendritic growth technique. The dendritic functional-group amplification process was demonstrated to increase the loading of hexahisitidine tagged proteins on silica surfaces by more than 40%, as compared to traditional immobilization procedures.
149

訪生科技應用在瑪瑙斯市建築的限制:需求面分析 / A Biomimetic Lodge District for Manaus: A Demand Side Analysis

毛祿生, Marmolejo, Luis Unknown Date (has links)
Emerging environmental designs have reacted toward a new environmental scope and agenda to provide a better understanding of functionality and sustainability. Biomimicry is a recent environmental approach that mimics nature for improving processes and structures design. This has important consequences for urban development and planning. The most relevant for us is that these new structures help us to breakdown the false dichotomy between landscape and architecture and therefore are ideal to integrate urban planning and to rethink environmental standards within ongoing development. The main objective of this study is to determine the feasibility of building a peripheral district in Manaus using biomimicry designed lodges. Our main interest is to identify the types of customers that could be involved in this urban development project. This study analyzes the willingness of customers to go for a biomimicry lodge. The analyzed information will come from a survey of a non-randomized population. Our target group are mature postmodern societies -sorted out by country of residence and willingness to travel-. The sample tested different attitudes, values and beliefs on environment which will help us to break down patterns of consumption using the literature review as reference. The study uses ordinary least squares (OLS) to determine significant predictors for different types of customers. This survey might help environmental activists, local authorities and social entrepreneurs with data for successfully developing alternative environmental designs. Our direct clients are real estate developers, social entrepreneurs and the business community in general. However, these results have also an indirect effect on the actual state of environmental design trends and on policy making. Local authorities might consider these results for agenda setting and as well for mobilizing civil society for better ecological practices.
150

Molecularly imprinted polymer sensors for the detection of phosphate in agriculture

Storer, Christopher January 2017 (has links)
Molecularly imprinted polymers (MIPs) are biomimetic sensing elements that combine the accuracy and highly specific binding affinity of a biosensor, with the robustness and reusability associated with artificial electrochemical sensors. This thesis investigates the application of a MIP sensor to address the challenge of phosphate detection in precision agriculture. Traditional chemical sensing approaches using portable electrochemical sensors display a significant cross-interference between inorganic phosphate and other nutrient ions. This is due to the low position of phosphate in the Hofmeister Selectivity Series for anions, its high electronegativity and its pH dependent structure, resulting in a molecule that is very difficult to detect. To address this challenge, a sensor was created by spin coating a phosphate selective MIP onto a substrate containing a series of electrodes. These electrode devices allowed for electrical measurements to be taken using an inductance, capacitance and resistance (LCR) testing station, and to observe the change in the materials dielectric constant as the binding sites become occupied by the target analyte. The devices underwent several design reiterations to produce an optimised setup consisting of 100 interdigitated chrome electrodes with a width of 1 μm and a separation distance of 1 μm on a quartz substrate. The final electrode design was used to carry out a nutrient cross-interference study across several polymer permutations. The purpose of this was to develop an optimised MIP formulation for binding specifically to inorganic phosphate ions. From this study, an optimal phosphate selective MIP was identified, based upon a binding site constructed from methacrylic acid around a diphenyl phosphate template molecule. During capacitance measurements, this MIP formulation demonstrated a clear preferential response to phosphate (1610 pF) over the average capacitance results observed following exposure to the competing nitrate (1286 pF) and sulphate (1212 pF) nutrients tested in the cross-interference study.

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