Dissertations / Theses on the topic 'Motion response'
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Hofmann, Lorenz M. "The flow response to actuator motion /." The Ohio State University, 1996. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487941504296049.
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Ohnishi, Yusuke. "Temporal impulse response function of the visual system estimated from ocular following responses in humans." 京都大学 (Kyoto University), 2017. http://hdl.handle.net/2433/225484.
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Piolatto, Alex. "Structural response including vertical component of ground motion /." Available to subscribers only, 2009. http://proquest.umi.com/pqdweb?did=1966541941&sid=4&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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Jeong, Seokho. "Topographic amplification of seismic motion including nonlinear response." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50325.
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Topography effects, the modification of seismic motion by topographic features, have been long recognized to play a key role in elevating seismic risk. Site response, the modification of ground motion by near surface soft soils, has been also shown to strongly affect the amplitude, frequency and duration of seismic motion. Both topography effects and 1-D site response have been extensively studied through field observations, small-scale and field experiments, analytical models and numerical simulations, but each one has been studied independently of the other: studies on topography effects are based on the assumption of a homogeneous elastic halfspace, while 1-D site response studies are almost exclusively formulated for flat earth surface conditions.
This thesis investigates the interaction between topographic and soil amplification, focusing on strong ground motions that frequently trigger nonlinear soil response. Recently, a series of centrifuge experiments tested the seismic response of single slopes of various inclination angles at the NEES@UCDavis facility, to investigate the effects of nonlinear soil response on topographic amplification. As part of this collaborative effort, we extended the search space of these experiments using finite element simulations. We first used simulations to determine whether the centrifuge experimental results were representative of free-field conditions. We specifically investigated whether wave reflections caused by the laminar box interfered with mode conversion and wave scattering that govern topographic amplification; and whether this interference was significant enough to qualitatively alter the observed amplification compared to free-field conditions. We found that the laminar box boundaries caused spurious reflections that affected the response near the boundaries; however its effect to the crest-to-free field spectral ratio was found to be insignificant. Most importantly though, we found that the baseplate was instrumental in trapping and amplifying waves scattered and diffracted by the slope, and that in absence of those reflections, topographic amplification would have been negligible. We then used box- and baseplate-free numerical models to study the coupling between topography effects and soil amplification in free-field conditions.
Our results showed that the complex wavefield that characterizes the response of topographic features with non-homogeneous soil cannot be predicted by the superposition of topography effects and site response, as is the widespread assumption of engineering and seismological models. We also found that the coupling of soil and topographic amplification occurs both for weak and strong motions, and for pressure-dependent media (Nevada sand), nonlinear soil response further aggravates topographic amplification; we attributed this phenomenon to the reduction of apparent velocity that the low velocity layers suffer during strong ground motion, which intensifies the impedance contrast and accentuates the energy trapping and reverberations in the low strength surficial layers. We finally highlighted the catalytic effects that soil stratigraphy can have in topographic amplification through a case study from the 2010 Haiti Earthquake. Results presented in this thesis imply that topography effects vary significantly with soil stratigraphy, and the two phenomena should be accounted for as a coupled process in seismic code provisions and seismological ground motion predictive models.
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Piolatto, Alex Joseph. "Structural Response Including Vertical Component of Ground Motion." OpenSIUC, 2009. https://opensiuc.lib.siu.edu/theses/112.
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Evidence indicates that the vertical component of ground motion is more significant than previously thought, especially for near fault events. However, many design codes do not reflect the importance of the vertical component of ground motion. Therefore, the purpose of this thesis is to determine what effects the vertical component of ground motion has on a structure by way of comparison. Specifically, structural response due to the lateral components of ground acceleration is compared to structural response due to all three components of ground acceleration. Structural response includes the following parameters: story drift; axial force; shear; torsion; and bending moment. Variables are fundamental period of vibration, ground motion record, and presence of cross-bracing. Through nonlinear dynamic time history analysis, it is shown that the vertical component of ground motion greatly affects axial force response for these short-period frames. However, the story drift is unaffected for the short, medium, and long-period frames. Other parameters show varying degrees of dependence or independence in relation to the vertical component of ground motion.
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Cornforth, Whitney Alan 1977. "Simulation of motion response of spar type oil platform." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/91351.
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Chase, Robert Edward. "Structural Response and Risk Considering Regional Ground Motion Characteristics." Thesis, University of Colorado at Boulder, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=10981024.
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Regions of the U.S. have different tectonic environments and, correspondingly, seismic ground motion characteristics can vary significantly across the country. Structures’ seismic risk depends greatly on these characteristics, which can significantly influence structural seismic response. Current seismic design procedures and many typical assessments only consider ground motion intensity at a structure’s fundamental period, and not motion characteristics like frequency content and ground motion duration. This dissertation explores the relationships between regional ground motion characteristics and structural risk through three studies that aim to fill this gap in the literature.
Chapter 2 investigates induced earthquakes in the central U.S. to investigate the characteristics of ground motions and resulting structural response. Ground motion suites of induced motions and tectonic motions with similar earthquake source characteristics are gathered for dynamic analysis on a numerical model of a residential chimney. Tectonic motions are found to produce slightly higher probabilities of chimney collapse, when compared to induced motions of the same intensity. These higher probabilities are due to differences in the frequency content, which stem from differences in depth, stress drop, and regional seismic environment between the two ground motion sets.
Chapter 3 analyzes light-frame wood buildings in sequences of induced motions, through dynamic simulations, to investigate damage and seismic loss accumulation in multiple shaking events. The study finds that, although cracks widen and elongate in subsequent events, the vulnerability of new light-frame wood construction does not increase when initially damaged at levels observed in recent induced events. However, seismic losses or repair costs may increase dramatically if owners are repairing after every event.
In Chapter 4, light-frame wood buildings are simulated using hazard-consistent incremental dynamic analysis to assess collapse capacities and expected seismic loss, for one to four-story commercial and multifamily buildings at sites in California and the Pacific Northwest. Modification factors for design base shear are developed for these buildings to account for site-specific spectral shape. Collapse risk, losses, and design base shear are found to be higher for sites with larger contributions from subduction hazards, due to broader motion frequency content and, to a lesser extent, longer shaking durations.
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Koukleri, Stavroula. "Inelastic earthquake response and design of multistorey torsionally unbalanced structures." Thesis, University College London (University of London), 2000. http://discovery.ucl.ac.uk/1349433/.
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Structures exhibit coupled torsional and translational responses to earthquake ground motion input if their centres of floor mass and their centres of resistance do not coincide. However, torsional motions may occur even in nominally symmetric structures due to accidental eccentricity and torsional ground motions. The sources giving rise to accidental eccentricity include the difference between the assumed and actual distributions of mass and stiffness, asymmetric yielding strength, non-linear patterns of force-deformation relationships, and differences in coupling of the structural foundation with the supporting soil. Symmetric and regular buildings that are properly designed have a much higher ability to survive a strong earthquake event than asymmetric buildings and their response to earthquake loading is far more straightforward to predict and design for. On the other hand, even though the response of asymmetric buildings is more unpredictable, designers still have to compromise structural regularity to accommodate functional and aesthetic needs. As a result, serious and widespread damage associated with structural asymmetry has been observed repeatedly in past major earthquakes. In the first studies examining torsional effects in buildings, attention was focused on the elastic structural behaviour of single-storey buildings and the main purpose was to achieve a complete understanding of the effects of mass and stiffness eccentricities and to evaluate them by simple static models. However, as the response of real structures is mainly inelastic, these studies gave poor information on torsional behaviour and interest has moved towards non-linear response studies. In an effort to clarify some of the issues influencing the inelastic torsional response of multistorey asymmetric structures, this thesis presents a series of coherent parametric investigations. These investigations include comparing the response of various reference models to the performance of code-designed torsionally unbalanced structures. An extensive parametric investigation of torsionally responding structures designed as stipulated by a selection of major earthquake building codes is presented and the adequacy of the static torsional provisions is assessed for a wide range of structural configurations and parameters. Detailed investigations of torsionally asymmetric structures incorporating frame elements oriented along both orthogonal axes of the structure are also conducted and the effect of including the second earthquake component to simultaneously excite the structural models is quantified. The relative merits and deficiencies of each code provision are discussed and a new proposed optimised method is tested. All fundamental conclusions from the investigations conducted are presented and various topics for further research are proposed, which are considered to be both necessary and pertinent for increasing and refining the knowledge and understanding the complex behaviour of multistorey torsionally asymmetric buildings.
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Misovec, Kathleen. "The effect of flight simulator motion on modelled vestibular response." Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/83660.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1986.Microfiche copy available in Archives and Barker.
Bibliography: leaves [133]-[134].
by Kathleen M. Misovec.
M.S.
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Wallis, Barbara Diana. "Mathematical modelling of the dynamic response, in six degrees of freedom, of small vessels in a seaway." Thesis, University of Plymouth, 1997. http://hdl.handle.net/10026.1/1725.
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This thesis treats the motion of a small vessel described in six degrees of freedom. There are three are translation equations of motion and the other three are equations of angular motion. The aim is to develop a model with a sound mathematical base and use experimentation to find forces to aid the completion of the model, with the intention of use in an auto pilot, by the following means: 1) By solving the equations of motion for large movements, with given sea and wind conditions and also with given control forces and moments. 2) Deduce the forces and moments being applied from the sea etc., from the motion of the vessel. Thus to enable the auto pilot to deduce the required additional forces and the forces and moments applied by the water and wind and the control devices, such as the propeller and rudder. These two aims are achieved by analysing the transformation of axes using the standard Euler equations. However, as Euler's angles are ordered and therefore cannot cope with large angles which are present in the motion of a small vessel, another set of angles relating to axes and planes have been deduced. These are then rotated and the set of three measured angles are found in terms of the Euler angles. This is the main pan of original work in the thesis. The rest of the thesis is then based upon these set of measured angles and a general case mathematical model is deduced using them. This is proceeded by a functional analysis of the vessel's motion, environment and control action's. After that the general case model is theoretically validated by analysing the work done by ARJM Lloyd and showing how his work is a specific case of the general case. Experimental work performed on a small vessel is then used in the building of a mathematical model for the specific case of a small vessel, using a set of measured angles.
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Zamiran, Siavash. "Numerical Analysis on Seismic Response of Cantilever Retaining Wall Systems and Fragility Analysis on Motion Response." OpenSIUC, 2017. https://opensiuc.lib.siu.edu/dissertations/1475.
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In this investigation, seismic response of retaining walls constructed with cohesive and cohesionless backfill materials was studied. Fully dynamic analysis based on finite difference method was used to evaluate the performance of retaining walls during the earthquake. The analysis response was verified by the experimental study conducted on a retaining wall system with cohesive backfill material in the literature. The effects of cohesion and free-field peak ground acceleration (PGA) on seismic earth thrust, the point of action of earth thrust, and maximum wall moment during the earthquake were compared with analytical and experimental solutions. The numerical results were compared with various analytical solutions. The motion characteristics of the retaining wall during the earthquake were also considered. The relative displacement of the walls with various backfill cohesions, under different ground motions, and free-field PGAs were investigated. Current analytical and empirical correlations developed based on Newmark sliding block method for estimating retaining wall movement during earthquakes were compared with the numerical approach. Consequently, fragility analyses were conducted to determine the probability of damage to the retaining walls. To evaluate the fragility of the studied models, specific failure criterion was chosen for retaining walls based on the suggested methods in practice. Using numerical approaches, the effects of soil-wall interaction and wall rigidity on the seismic response of retaining walls were also evaluated in earthquake conditions for both cohesive and cohesionless backfill materials. According to the findings, practical correlations were presented for conducting the seismic design of retaining walls.
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Chen, Shin-Juh. "Response of blade-row to upstream vortical disturbance in relative motion." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/47382.
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Kiyono, Junji. "IDENTIFICATION AND SYNTHESIS OF SEISMIC GROUND MOTION IN STRUCTURAL RESPONSE ANALYSES." Kyoto University, 1992. http://hdl.handle.net/2433/74615.
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Motamed, Maryam. "Effects of Site Response on the Correlation Structure of Ground Motion Residuals." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/25333.
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Seismic hazard analyses require an estimate of earthquake ground motions from future events. These predictions are achieved through Ground Motion Prediction Equations, which include a prediction of the median and the standard deviation of ground motion parameters. The differences between observed and predicted ground motions, when normalized by the standard deviation, are referred to as epsilon (𝜖). For spectral accelerations, the correlation structure of normalized residuals across oscillator periods is important for guiding ground motion selection. Correlation structures for large global datasets have been studied extensively. These correlation structures reflect effects that are averaged over the entire dataset underlying the analyses. This paper considers the effects of site response, at given sites, on the correlation structure of normalized residuals. This is achieved by performing site response analyses for two hypothetical soil profiles using a set of 85 rock input motions. Results show that there is no significant difference between correlation coefficients for rock ground motions and correlation coefficients after considering the effects of site response for the chosen sites.Master of Science
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Tsujii, Masato. "Response and design of steel-concrete composite frames subjected to earthquake motion." Thesis, Imperial College London, 2001. http://hdl.handle.net/10044/1/7454.
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Fisher, Karl Albert. "Structural and acoustic response of motion sensors mounted on a compliant coating." Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/16637.
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Musselman, Ryan William. "Effect of Ornamentation on the Emotion Response and Perception of Motion Graphics." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/23265.
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This study explores the effect of ornamentation on the emotional response and perception of motion graphics. A series of motion graphics were created, eye tracked, and tested for changes in emotional responses and perceptions based on the amount of ornamentation in the design. This study collected both quantitative and qualitative data to gain a better understanding of the viewer\'s overall emotional responses and perceptions of each video. Eye tracking data was studied to validate focal points and areas of interest. The quantitative data was analyzed by looking for correlations and trends. The qualitative data was analyzed for trends and reoccurring ideas.This study found that the amount of ornamentation in logo animations has a direct effect on the viewer\'s emotional responses and perceptions. More ornamentation led to overall positive changes in the emotional responses and perceptions of the brand or message, however there can be a turning point where the ornamentation can cause a negative response from the viewer.
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Sedlackova, Anna. "Replicating Motion Vision and Response in Insects Using a Synthetic Nervous System." Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case1593309220545937.
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Esbjörnsson, Liljedahl Mona. "Human muscle response to sprint exercise in a gender perspective /." Stockholm, 2000. http://diss.kib.ki.se/2000/91-630-8825-8/.
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Bidwell, Nicola Jane. "Response characteristics of motion-sensitive descending neurons in the worker honeybee (Apis mellifera)." Thesis, Queen Mary, University of London, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249823.
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Šimic, Marko, and Niko Herakovič. "High-response hydraulic linear drive with integrated motion sensor and digital valve control." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-199381.
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Main purpose of the paper is to present high-response hydraulic linear drive, which is controlled with new digital piezo valve and where the new position transducer is integrated as a part of hydraulic cylinder. Hydraulic digital piezo valve with main static and dynamic characteristics as well as its functionality is presented in detail. The main static and dynamic characteristics of dygital piezo valve which influence directly on the linear drive performance are high resolution of the volume flow rate and high resposne of the valve. Beside valve characteristics the new integrated position transducer, the digital controller and control method, presented in the paper, have major impact on linear drive preformance. At the end of the paper the step response and position
resolution of the hydraulic linear drive controlled with the new digital valve is compared with the results of reference hydraulic drive controlled with high response proportional valve.
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Sugito, Masata. "EARTHQUAKE MOTION PREDICTION, MICROZONATION, AND BURIED PIPE RESPONSE FOR URBAN SEISMIC DAMAGE ASSESSMENT." Kyoto University, 1987. http://hdl.handle.net/2433/138405.
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Sugita, Yuko. "Principal Fourier component of motion stimulus dominates the initial optokinetic response in mice." Kyoto University, 2013. http://hdl.handle.net/2433/174825.
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Lee, Bryce Kenji Tim-Sung. "Design of a Humanoid Robot for Disaster Response." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/47492.
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This study focuses on the design and implementation of a humanoid robot for disaster response. In particular, this thesis investigates the lower body design in detail with the upper body discussed at a higher level. The Tactical Hazardous Operations Robot (THOR) was designed to compete in the DARPA Robotics Challenge where it needs to complete tasks based on first-responder operations. These tasks, ranging from traversing rough terrain through driving a utility vehicle, suggest a versatile platform in a human sized form factor. A physical experiment of the proposed tasks generated a set of joint range of motions (RoM). Desired limb lengths were determined by comparing existing robots, the test subject in the experiment of proposed tasks, and an average human. Simulations using the desired RoM and limb lengths were used to calculate baseline joint torques.
Based on the generated design constraints, THOR is a 34 degree of freedom humanoid that stands 1.78 [m] tall and weighs 65 [kg]. The 12 lower body joints are driven by series elastic linear actuators with multiple joints actuated in parallel. The parallel actuation mimics the human body, where multiple muscles pull on the same joint cooperatively. The legs retain high joint torques throughout their large RoM with some joints achieving torques as high as 289 [Nm]. The upper body uses traditional rotary actuators to drive the waist, arms, and head. The proprioceptive sensor selection was influenced by past experience on humanoid platforms, and perception sensors were selected to match the competition.Master of Science
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Malm, Christer. "Immunological changes in human blood and skeletal muscle in response to physical exercise /." Stockholm : Karolinska Univ. Press, 2001. http://diss.kib.ki.se/2001/91-7349-035-0/.
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Rana, Suman. "RISK-TARGETED GROUND MOTION FOR PERFORMANCE- BASED BRIDGE DESIGN." OpenSIUC, 2017. https://opensiuc.lib.siu.edu/theses/2137.
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The seismic design maps on ASCE 7-05, International Building Code- 2006/2009, assumed uniform hazard ground motion with 2% probability of exceedance in 50 years for the entire conterminous U.S. But, Luco et al in 2007 pointed out that as uncertainties in collapse capacity exists in structures, an adjustment on uniform hazard ground motion was proposed to develop new seismic design maps. Thus, risk-targeted ground motion with 1% probability collapse in 50 years is adopted on ASCE 7-10. Even though these seismic design maps are developed for buildings, performance-based bridge design is done using same maps. Because significance difference lies on design procedure of buildings and bridges this thesis suggests some adjustment should be made on uncertainty in the collapse capacity(β) when using for bridge design. This research is done in 3 cities of U.S— San Francisco, New Madrid and New York. Hazard curve is drawn using 2008 version of USGS hazard maps and risk- targeted ground motion is calculated using equation given by Luco et al adjusting the uncertainty in collapse capacity(β) to be 0.9 for bridge design instead of 0.8 as used for buildings. The result is compared with existing result from ASCE 7-10, which uses β=0.6. The sample design response spectrum for site classes A, B, C and D is computed for all 3 cities using equations given in ASCE 7-10 for all β. The design response spectrum curves are analyzed to concluded that adjustment on uncertainty in collapse capacity should be done on ASCE 7-10 seismic design maps to be used for performance-based bridge design.
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Eklund, Frida. "Make people move : Utilizing smartphone motion sensors to capture physical activity within audiences during lectures." Thesis, KTH, Visualisation - Interaction - Collaboration, VIC, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-233369.
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It takes only about 10-30 minutes into a sedentary lecture before audience attention is decreasing. There are different ways to avoid this. One is to use a web-based audience response systems (ARS), where the audience interact with the lecturer through their smartphones, and another is to take short breaks, including physical movements, to re-energize both the body and the brain. In this study, these two methods have been combined and explored. By utilizing the motion sensors that are integrated in almost every smartphone, a physical activity for a lecture audience was created and implemented in the ARS platform Mentimeter. The proof of concept was evaluated in two lectures, based on O’Brien and Toms' model of engagement. The aim was to explore the prerequisites, both in terms of design and implementation, for creating an engaging physical activity within a lecture audience, using smartphone motion sensors to capture movements and a web-based ARS to present the data. The results showed that the proof of concept was perceived as fun and engaging, where important factors for creating engagement were found to be competition and a balanced level of task difficulty. The study showed that feedback is complicated when it comes to motion gesture interactions, and that there are limitations as to what can be done with smartphone motion sensors using web technologies. There is great potential for further research in how to design an energizing lecture activity using smartphones, as well as in exploring the area of feedback in motion gesture interaction.Efter bara 10-30 minuter på en stillasittande föreläsning börjar publiken tappa i koncentration. Det går undvika på olika sätt. Ett sätt kan vara genom att låta publiken bli mer aktiva i föreläsningen med hjälp av ett webb-baserat röstningsverktyg, där de använder sina smartphones för att interagera med föreläsaren, och ett annat sätt kan vara att ta korta pauser där publiken får röra på sig för att syresätta hjärna och kropp. I den här studien kombinerades dessa två metoder genom att utnyttja rörelsesensorerna som finns inbyggda i de flesta smartphones. En fysisk aktivitet för en föreläsningspublik togs fram och implementerades i ARS-plattformen Mentimeter och konceptet utvärderades sedan under två föreläsningar baserat på O’Brien and Toms' modell för engagemang. Målet var att utforska förutsättningarna, både inom teknik och design, för att skapa en engagerande fysisk aktivitet för en föreläsningspublik, där smartphonens rörelsesensorer används för att fånga rörelse och ett webb-baserat röstningssystem för att presentera data. Resultatet visade att konceptet upplevdes som kul och engagerande, där viktiga faktorer för att skapa engagemang fanns i att ha ett tävlingsmoment och en lagom svårighetsgrad. Studien visade även att feedback är komplicerat när det kommer till rörelseinteraktion, och att det finns begräsningarna i vad som kan göras med rörelsesensorerna i en smartphone med hjälp av webbteknologi. Det finns stor potential för ytterligare undersökningar både inom hur man kan skapa interaktiva aktiviteter på föreläsningar som ger publiken mer energi, men också inom området kring feedback för rörelseinteraktion.
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Ay, Bekir Ozer. "A Proposed Ground Motion Selection And Scaling Procedure For Structural Systems." Phd thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12615359/index.pdf.
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This study presents a ground-motion selection and scaling procedure that preserves the inherent uncertainty in the modified recordings. The proposed procedure provides a set of scaled ground-motion records to be used in the response estimation of structural systems for a pre-defined earthquake hazard level. Given a relatively larger ground-motion dataset, the methodology constrains the selection and scaling of the accelerograms to the differences between individual records and corresponding estimations from a representative ground-motion predictive model. The procedure precisely calculates the distribution parameters of linear structural systems whereas it provides estimations of these parameters for nonlinear structural response. Thus this method is not only useful for ground-motion selection and scaling but also for probability based performance assessment studies. The proposed procedure is also capable of matching with a pre-defined target elastic response spectrum and corresponding variance over a period range. Case studies that compare the performance of the proposed procedure with some other record selection and scaling methods suggest its usefulness for the accurate verification of structural systems and rapid loss estimation studies.
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Ng, Hoi-shan Crystal. "Rewriting Louis Cha's classical characters in filmic representation in response to the political and cultural mutation of Hong Kong 90S - Wong Kar Wai and Tsui Hark." Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B20272662.
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Guettler, Allison Jean. "Quantifying the Response of Relative Brain/Skull Motion to Rotational Input in the PMHS Head." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/82400.
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Post-mortem human surrogate (PMHS) head specimens were subjected to two different angular speed pulses. Each pulse was approximately a half-sine with either a peak angular speed of either 40 or 20 rad/s and duration of either 30 or 60 milliseconds. High-speed biplane x-ray was used to record the motion of the brain and skull via radio-opaque markers implanted at specified locations in the brain, and lead markers on the skull. Specimens were perfused to physiologic conditions throughout preparation and testing to maintain the integrity of the brain tissue and ensure coupling of the brain and skull. Intracranial pressure was measured anteriorly and posteriorly. The test event was controlled by a cam-follower-flywheel mechanism, which facilitated control of pulse parameters and provided a form of "infinite energy" so that the device and therefore the test input would not be influenced by the characteristics of the object under test. This approach kept the independent and dependent variables separated. The brain targets were also deployed in a prescribed manner with two methodologies that were scalable to different specimens. The repeatable input and target deployment schemes helped reduce experimental variation (between tests and subjects) to produce consistent response data. Displacement of the brain was calculated with respect to a body-fixed basis on the skull. The relative motion of the brain with respect to the skull was shown to be dependent on the location of the target in the brain. The major deformation axis of each target followed the contour of the skull or bony landmark to which it was closest. Intracranial pressure was relatively low because the changes were due to inertial effects in the absence of impact. Tests with lower speeds and longer durations produced less deformation, lower intracranial pressures, and longer pressure durations than the tests that were high-speed, short-duration. The response of the brain to rotation of the head was quantified at two test levels and on two PMHS specimens.Master of Science
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Lester, Alanna Paige. "An Examination of Site Response in Columbia, South Carolina: Sensitivity of Site Response to "Rock" Input Motion and the Utility of Vs(30)." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/33467.
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This study examines the sensitivity of calculated site response in connection with alternative assumptions regarding input motions and procedures prescribed in the IBC 2000 building code, particularly the use of average shear wave velocity in the upper 30 meters as an index for engineering design response spectra. Site specific subsurface models are developed for four sites in and near Columbia, South Carolina using shear wave velocity measurements from cone penetrometer tests. The four sites are underlain by thin coastal plain sedimentary deposits, overlying high velocity Paleozoic crystalline rock. An equivalent-linear algorithm is used to estimate site response for vertically incident shear waves in a horizontally layered Earth model. Non-linear mechanical behavior of the soils is analyzed using previously published strain-dependent shear modulus and damping degradation models.
Two models for material beneath the investigated near-surface deposits are used: B-C outcrop conditions and hard rock outcrop conditions. The rock outcrop model is considered a geologically realistic model where a velocity gradient, representing a transition zone of partially weathered rock and fractured rock, overlies a rock half-space. Synthetic earthquake input motions are generated using the deaggregations from the 2002 National Seismic Hazard Maps, representing the characteristic Charleston source. The U. S. Geological Survey (2002) uniform hazard spectra are used to develop 2% in 50 year probability of exceedance input ground motions for both B-C boundary and hard rock outcrop conditions. An initial analysis was made for all sites using an 8 meter thick velocity gradient for the rock input model. Sensitivity of the models to uncertainty of the weathered zone thickness was assessed by randomizing the thickness of the velocity gradient. The effect of the velocity gradient representing the weathered rock zone increases site response at high frequencies.
Both models (B-C outcrop conditions and rock outcrop conditions) are compared with the International Building Code (IBC 2000) maximum credible earthquake spectra. The results for both models exceed the IBC 2000 spectra at some frequencies, between 3 and 10 Hz at all four sites. However, site 2, which classifies as a C site and is therefore assumed to be the most competent of the four sites according to IBC 2000 design procedures, has the highest calculated spectral acceleration of the four sites analyzed. Site 2 has the highest response because a low velocity zone exists at the bottom of the geotechnical profile in immediate contact with the higher velocity rock material, producing a very large impedance contrast. An important shortcoming of the IBC 2000 building code results from the fact that it does not account for cases in which there is a strong rock-soil velocity contrast at depth less than 30 meters. It is suggested that other site-specific parameters, specifically, depth to bedrock and near-surface impedance ratio, should be included in the IBC design procedures.Master of Science
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Chang, Tsu-Sheng. "A study of seismic response of rotating machines subjected to multi-component base excitation." Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-05042010-020148/.
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Su, Yan. "Numerical and experimental study of the wave response of floating support with partially filled tank." Thesis, Ecole centrale de Marseille, 2014. http://www.theses.fr/2014ECDM0007/document.
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Ce travail traite du ballottement d'un fluide dans une cuve rectangulaire en mouvement et du couplage avec un corps flottant. Nous exposons premièrement une théorie linéaire basée sur la décomposition des mouvements dans la base des modes propres de la cuve. Pour les mouvements plus importants la théorie linéaire atteint ses limites, nous proposons un modèle de type Boussinesq et un modèle d'équations intégrales avec des conditions de surface libre complètement non-linéaires. Nous considérons également un terme d'amortissement linéarisé. Nous comparons les résultats numériques à des résultats expérimentaux pour une cuve à fond plat et pour un fond légèrement incliné. Le taux de remplissage varie également. Le couplage de la cuve avec une barge rectangulaire est réalisé par développement en série de fonctions propres et par leur raccordement aux frontières des différents sous-domaines. Tous ces résultats, numériques et expérimentaux , sont comparés dans le domaine fréquentiel et temporelThis work focuses on the sloshing of the fluid in rectangular tanks with forced motions and of the coupling with a floating body. A linear theory is firstly given for the sloshing which is represented by the superposition of natural sloshing modes. Compared with linear theory, the extended Boussinesq-type models are used for the simulations of nonlinear sloshing motions. The fully nonlinear free surface conditions are adopted and linear damping term is considered in the model. The integral equation method with fully nonlinear free surface conditions are also applied. A flat bottom rectangular tank with different filling levels are discussed based on these numerical methods and experiences. The solutions of an inclined bottom tank are studied and compared with experimental results. The sea-keeping of a rectangular barge is modeled by a series of eigen-functions. The coupled computations of the sloshing in the tank and the sea-keeping of floating body are studied in both the frequency domain and time domain. The numerical results are compared with experimental results
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Zirbel, Shannon Alisa. "Characterization of the Mechanical Response of the Lumbar Spine." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2783.
Full textAbstract:
The primary objective of this research is to associate lumbar segmental mechanical response with intervertebral disc degeneration under physiologic testing conditions. Because no mathematical model exists for lumbar spine segmental rotations, a portion of this thesis evaluates potential methods for curve fitting the torque-rotation curves. The Dual Inflection Point (DIP) Boltzmann equation was developed during the course of this research and is presented here as a method for fitting spinal motion data wherein a physical meaning can be assigned to each of the model coefficients. This model can tell us more about the effects of degeneration, testing conditions, and other factors that are expressed in the change in spinal motion. Previous studies have investigated the relationship between the degeneration grade and flexibility of the intervertebral disc, but were completed without the presence of a compressive follower load. This study builds on past work by performing the testing under a compressive follower load. Segmental stiffness, range of motion (ROM), hysteresis area, and normalized hysteresis (hysteresis area/ROM) were evaluated and the effect of degeneration, segment level, temperature, and follower load were analyzed. Twenty-one functional spinal units (FSUs) were tested in the three primary modes of loading at both body temperature and room temperature in a near 100% humidity environment. A compressive follower load of 440 N was applied to simulate physiologic conditions. Fifteen of the twenty-one segments were also tested without the follower load to determine the effects of the load on segmental biomechanics. The grade of degeneration for each segment was determined using the Thompson scale and the torque-rotation curves were fit with the DIP-Boltzmann sigmoid curve.The effect of degeneration was statistically significant (α = 0.05) for stiffness, ROM, and hysteresis area in axial rotation (AR) and lateral bending (LB); it was also statistically significant for ROM and normalized hystersis in flexion-extension (FE). The lumbosacral joint (L5-S1) was significantly stiffer in AR and LB; the decrease in ROM and hysteresis area in AR and LB were also statistically significant for the lumbosacral joint compared to L1-L2 and L3-L4. Temperature had a significant effect on stiffness and hysteresis area in AR and on hysteresis area in LB. The follower load increased stiffness in all three modes of loading, but was significant only in AR and LB; it also reduced ROM and increased normalized hysteresis in all three modes of loading.
35
Choi, Hoon. "Effects of near-fault ground motion and fault-rupture on the seismic response of reinforced concrete bridges." abstract and full text PDF (free order & download UNR users only), 2007. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3289465.
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Matheson, A. L. "The influence of facial motion on the neural response during emotion perception in typical and atypical development." Thesis, University College London (University of London), 2012. http://discovery.ucl.ac.uk/1346471/.
Full textAbstract:
The ability to interpret emotional expressions is the key to understanding our social environment. In our everyday lives we are exposed to a huge variety of facial expressions which are constantly updated in response to environmental cues. The neural networks underpinning our cognitive ability to perceive dynamic emotional expressions are poorly understood. This thesis aims to address the effects of motion on our perception of emotional expression from a developmental perspective. The overall aim was to compare the neural correlates of emotion perception of static and dynamic images for the six basic facial expressions in typical and atypical development. Three populations were studied: 1) typically developed adults; 2) atypically developed adults, i.e. young adults who have undergone a surgical resection for paediatric temporal lobe epilepsy; and 3) typically developing infants (4-12-month-olds). Initially, morphed dynamic images for the six basic facial expressions were created, to be used in subsequent studies. These were validated, alongside static photographs, with ratings for accuracy, confidence and intensity. The first and second ERP studies, involving typically developed adults and atypically developed adults respectively, explored the amplitude and latency of the P1 and N170 event-related potential (ERP) components in response to observing static and dynamic images of facial expressions. The final study, involving typically developing infants, explored the amplitude and latency of the P1 and N290 (the N170 precursor). The impact of motion on the development of emotion perception is discussed in relation to the findings presented in this thesis.
37
Lewis, Benjamin C. "Radiotherapy Response Using Intravoxel Incoherent Motion Magnetic Resonance Imaging in Liver Patients Treated with Stereotactic Body Radiotherapy." VCU Scholars Compass, 2019. https://scholarscompass.vcu.edu/etd/5821.
Full textAbstract:
Magnetic resonance imaging is utilized as an important tool in radiation oncology for delineation of healthy and cancerous tissues, and evaluating the functionality of those tissues, structures, and organs. Currently, the clinical imaging protocol at Virginia Commonwealth University includes anatomical imaging for tissue and structure delineation, and to observe treatment induced changes. Diffusion weighted imaging (DWI) is also acquired for calculation of apparent diffusion coefficient (ADC) values to provide quantitative information on tissue diffusivity and microstructure. However, anatomical images and ADC values may not display the true extent of changes in tissue. This work seeks to further utilize the capabilities of MRI and expand its role in treatment response monitoring for liver cancer patients treated with stereotactic body radiotherapy (SBRT). To do so, an imaging protocol and image analysis methodology to evaluate treatment changes on pre- and post-treatment image sets was developed. An extension of DWI, termed intravoxel incoherent motion (IVIM) imaging, was utilized to quantitatively assess levels of perfusion and diffusion within the liver and tumor. Acquisition of high-quality diffusion weighted images of the liver necessitated the development of an MR safe respiratory motion management device, which was designed, constructed and evaluated in this work. An imaging protocol was developed providing anatomical and functional images of the liver, acquired under breath hold, utilizing the respiratory motion management device. An IVIM parameter calculation and texture analysis workflow was developed using MATLAB, and applied to acquired data sets from multiple studies, including past clinical cases, investigator, healthy volunteer, and liver cancer patient . Differences in IVIM and texture analysis parameters were investigated for healthy and diseased tissue, and for select dose regions from pre- and post-treatment imaging sessions. Significant differences, at a voxel level, were found between healthy and diseased tissue, and pre- and post-treatment volumes, for multiple parameters, including apparent diffusion coefficient, pure diffusion, and perfusion, as well as for various texture features. Overall, this study showed the potential of IVIM and texture analysis to be used for discriminating between healthy and diseased tissues in the liver, and for indication of treatment response.
38
Syed, Riaz. "Development of Computational Tools for Characterization, Evaluation, and Modification of Strong Ground Motions within a Performance-Based Seismic Design Framework." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/36435.
Full textAbstract:
One of the most difficult tasks towards designing earthquake resistant structures is the determination of critical earthquakes. Conceptually, these are the ground motions that would induce the critical response in the structures being designed. The quantification of this concept, however, is not easy. Unlike the linear response of a structure, which can often be obtained by using a single spectrally modified ground acceleration history, the nonlinear response is strongly dependent on the phasing of ground motion and the detailed shape of its spectrum. This necessitates the use of a suite (bin) of ground acceleration histories having phasing and spectral shapes appropriate for the characteristics of the earthquake source, wave propagation path, and site conditions that control the design spectrum. Further, these suites of records may have to be scaled to match the design spectrum over a period range of interest, rotated into strike-normal and strike-parallel directions for near-fault effects, and modified for local site conditions before they can be input into time-domain nonlinear analysis of structures. The generation of these acceleration histories is cumbersome and daunting. This is especially so due to the sheer magnitude of the data processing involved.
The purpose of this thesis is the development and documentation of PC-based computational tools (hereinafter called EQTools) to provide a rapid and consistent means towards systematic assembly of representative strong ground motions and their characterization, evaluation, and modification within a performance-based seismic design framework. The application is graphics-intensive and every effort has been made to make it as user-friendly as possible. The application seeks to provide processed data which will help the user address the problem of determination of the critical earthquakes. The various computational tools developed in EQTools facilitate the identification of severity and damage potential of more than 700 components of recorded earthquake ground motions. The application also includes computational tools to estimate the ground motion parameters for different geographical and tectonic environments, and perform one-dimensional linear/nonlinear site response analysis as a means to predict ground surface motions at sites where soft soils overlay the bedrock.
While EQTools may be used for professional practice or academic research, the fundamental purpose behind the development of the software is to make available a classroom/laboratory tool that provides a visual basis for learning the principles behind the selection of ground motion histories and their scaling/modification for input into time domain nonlinear (or linear) analysis of structures. EQTools, in association with NONLIN, a Microsoft Windows based application for the dynamic analysis of single- and multi-degree-of-freedom structural systems (Charney, 2003), may be used for learning the concepts of earthquake engineering, particularly as related to structural dynamics, damping, ductility, and energy dissipation.Master of Science
39
Sakurai, Atsunori. "Exploring Nonlinear Responses of Quantum Dissipative Systems from Reduced Hierarchy Equations of Motion Approach." 京都大学 (Kyoto University), 2013. http://hdl.handle.net/2433/179368.
Full text
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Jin, Di. "Cell-cycle dependent motility of Chlamydomonas reinhardtii and its collective motion in response to a Hagen-Poiseuille flow." Thesis, University of Cambridge, 2019. https://www.repository.cam.ac.uk/handle/1810/284912.
Full textAbstract:
Motility of unicellular algal cells, especially its ability to respond to environmental cues, is crucial in industrial and ecological contexts and has been studied extensively with the model organism Chlamydomonas. However, little is known about the relationship between motility and the cell-cycle, despite the apparent link of mitosis dependent morphological changes which involve the flagella and the dependency on light/dark conditions of the cellular reactions. In this study, the cell swimming speed, the rotational diffusivity and its swimming bias against gravity were measured with high-speed video microscopy with Chlamydomonas reinhardtii cultures highly synchronised to a diurnal cycle. A simulation of gravitactic cell trajectories was developed to assist the statistical analysis of the cell trajectories from the images, which subject to a projection effect and has not been addressed previously. Its morphological changes, including cell size, shape, mass density, and presence of flagella were also evaluated. Un unforeseen change of cell motility at a critical mitosis time point was discovered, and our analysis suggests a connection to the alternating cell energetic regimes rather than the cell morphology. As indicated by results obtained from imaging based experimental measurements and by computational methods, the motility variation has direct consequences on the collective motion of algal cells in a Hagen-Poiseuille flow, a relevant component flow for air-lift photobioreactors. The cell number density profiles were calculated by an individual-based simulation and a continuum system inclusive of the buoyancy effect imposed by the aggregated cells on their surrounding fluid. Qualitative experimental-theoretical agreement suggests that the models can be employed for optimisation problems of photobioreactor flow designs inclusive of the non-negligible cell-cycle effects, which has been commonly overlooked in previous studies.
41
Petrunak, Denise. "Violence in Film: Narrative and Contextual Importance in Subjective Response." Honors in the Major Thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/790.
Full textAbstract:
This item is only available in print in the UCF Libraries. If this is your Honors Thesis, you can help us make it available online for use by researchers around the world by following the instructions on the distribution consent form at http://library.ucf.edu/Systems/DigitalInitiatives/DigitalCollections/InternetDistributionConsentAgreementForm.pdf You may also contact the project coordinator, Kerri Bottorff, at kerri.bottorff@ucf.edu for more information.Bachelors
Arts and Sciences
Psychology
42
Yenier, Emrah. "Limitations On Point-source Stochastic Simulations In Terms Of Ground-motion Models." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/3/12610308/index.pdf.
Full textAbstract:
In this study, the limitations of point-source stochastic simulations are investigated in terms of fundamental geophysical parameters. Within this context, a total of 6000 synthetic ground motions are generated for various magnitude (5.0 ≤
Mw &
#8804
7.5), source-to-site distance (less than 100 km), faulting style (shallow dipping and strike-slip) and site class (soft, stiff and rock) bins. The simulations are performed in two main stages: (1) the acceleration time series at outcropping very hard rock sites are simulated based on the stochastic method proposed by Boore (1983, 2003) and (2) they are modified through 1-D equivalent linear site response analysis to generate the free-field motions at soft, stiff and rock sites. Thus, as a part of this study, a probability-based soil profile model that considers the random variation of S-wave slowness as a function of depth is derived. The synthetic ground motions are assessed with several recent empirical ground-motion models to constitute the limitations of the simulation procedure. It is believed that the outcomes of this study will realistically describe the limitations of stochastic point-source simulation approach that can be employed further for the studies on improvements of this simulation technique.
43
Jiwaji, Aamera Hamzaali. "Negotiating the global : how young women in Nairobi shape their local identities in response to aspects of the mexican telenovela, Cuando seas mia." Thesis, Rhodes University, 2010. http://hdl.handle.net/10962/d1013364.
Full textAbstract:
Latin American telenovelas have been exported to more than a hundred countries across the globe. While they are popular in their country of production because their messages resonate with their audience’s everyday experiences, their popularity amongst global audiences with whom they share neither a social nor a cultural history is unexplained. Kenya has been importing and airing Latin American telenovelas since the early 1990s, and telenovelas have permeated many aspects of Kenyan daily life, when compared to other foreign globally-distributed media products that are aired on Kenyan television. As global media products, telenovelas remain open to criticisms from the media imperialism thesis. This research adopts an ethnographic approach to the study of audiences, and looks at the reception of a Mexican telenovela, Cuando Seas Mia, by a group of young Kenyan women in Nairobi. It reflects upon the media imperialism thesis from an African perspective by investigating the meanings that these women make from Cuando Seas Mia, and how these shape their changing local identities and cultures. The young women in this study, most of whom have moved to the city from the rural areas, are influenced by traditional, patriarchal Kenyan society and by the modern, Western influences of an urban environment. They experience a tension between their evolving rural and urban roles and identities and are drawn to telenovelas because their exploration of rural-urban themes holds a relevance to their own lives. They negotiate their contemporary African youth identities, gender roles and heterosexual relationships in relation to representations in the telenovela, questioning and destabilising African and Western definitions. These women select aspects from their traditional, African cultures and from their modern, Western experiences (and consumption of global media) and reconstruct them into a transitional youth identity which suits their day to day lives as young women living in an urban African environment.
44
TOMBARI, ALESSANDRO. "Seismic response of extended pile shafts considering nonlinear soil-pile interaction." Doctoral thesis, Università Politecnica delle Marche, 2013. http://hdl.handle.net/11566/242686.
Full textAbstract:
Il sistema pila-palo è largamente diffuso nelle strutture da ponte grazie ai suoi vantaggi
economici e tecnici. Tuttavia questo sistema è fortemente influenzato dagli effetti
dell’interazione dinamica terreno-palo-struttura. In aggiunta all’allungamento del periodo
fondamentale della struttura, la cedevolezza della fondazione induce una componente
rotazionale del moto sismico sul sistema globale che non può essere considerata mediante
le comuni procedure di progettazione sismica. Sebbene siano stati sviluppati modelli
avanzati per considerare l’interazione terreno-palo-struttura sia in campo lineare e non
lineare, i modelli alla Winkler rappresentano uno degli approcci più versatili.
In questo lavoro, un modello nonlineare di trave su suolo alla Winkler è stata utilizzato per
indagare l’effetto sulla risposta della struttura dei principali aspetti legati al comportamento
nonlineare del sistema terreno-fondazione, come ad esempio la plasticizzazione del terreno
, la formazione di distacco all’interfaccia palo-terreno, il collasso delle pareti del foro e il
degrado o incrudimento ciclico del terreno in prossimità del palo.
Sono state eseguite analisi dinamiche incrementali per valutare gli effetti della durata del
moto sismico e le non linearità del terreno sulle prestazioni della pila-palo in vari profili di
terreno omogeneo e bistrato sia di argilla satura che di sabbia nello stato asciutto o saturo
considerando differenti livelli di compattazione.
Si è stabilita una procedura per eseguire le analisi dinamiche incrementali considerando gli
effetti sia sulla risposta sismica locale sia sulle prestazioni strutturali. Gli effetti
dell’interazione cinematica ed inerziale in campo non lineare sono stati analizzati mediante
un’ampia indagine parametrica. Le analisi hanno evidenziato il ruolo determinante della
componente rotazionale e della durata del moto sismico sulla risposta sismica della pilapalo.
I risultati ottenuti sono inoltre stati confrontati con quelli ottenuti mediante un
modello lineare. Infine, vengono fatte alcune considerazioni evidenziando le aree grigie
della comune pratica di progettazione.Single column bents on extended pile shafts are widely used in bridges for their economical and technical advantages. Nevertheless, this system is strongly affected by Dynamic Soil- Pile-Structure Interaction. In addition to the lengthening of the fundamental period of the structure, the compliance of the foundation induces a rocking component of the seismic motion experienced by the overall system that cannot be considered by following the procedures of a common seismic design practice. Although advanced models have been developed in order to account for Soil-Pile-Structure Interaction both in the linear and nonlinear range, Winkler-type models represent one of the most feasible approaches. In this work, a Beam on Nonlinear Winkler Foundation model is used to investigate the importance of features typical in soil nonlinear behaviour such as yielding, gapping, soil cave-in and cyclic hardening/degradation effects on the performance of extended pile shafts. A procedure to estimate the model parameters from geotechnical soil characterization is presented. Incremental Dynamic Analyses are performed to evaluate the effects of Ground Motion Duration and soil nonlinearity on the performance of extended pile shafts in various homogeneous and two-layered soil profiles, including saturated clay and sand in either fully dry or saturated state with different levels of compaction. A procedure to perform Incremental Dynamic Analysis, including effects on both site response analysis and on the structural performance, is established. Nonlinear kinematic and inertial interaction effects are analyzed by means of an exhaustive parametric investigation. The significant effects of the rocking component and the Ground Motion Duration on the seismic response of extended pile shafts are demonstrated. Comparisons with results obtained with a linear model are also presented. Finally, some considerations are drawn pointing out grey areas of the common design practice.
45
Yoder, Steven J. "Occupant Response Metrics and Their Applicability to a Roll Simulator." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1322625198.
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Büch, Florian. "Seismic response of Little Red Hill - towards an understanding of topographic effects on ground motion and rock slope failure." Thesis, University of Canterbury. Geological Sciences, 2008. http://hdl.handle.net/10092/1251.
Full textAbstract:
A field experiment was conducted at near Lake Coleridge in the Southern Alps of New Zealand, focusing on the kinematic response of bedrock-dominated mountain edifices to seismic shaking. The role of topographic amplification of seismic waves causing degradation and possible failure of rock masses was examined. To study site effects of topography on seismic ground motion in a field situation, a small, elongated, and bedrock-dominated mountain ridge (Little Red Hill) was chosen and equipped with a seismic array. In total seven EARSS instruments (Mark L-4-3D seismometers) were installed on the crest, the flank and the base of the 210 m high, 500 m wide, and 800 m long mountain edifice from February to July 2006. Seismic records of local and regional earthquakes, as well as seismic signals generated by an explosive source nearby, were recorded and are used to provide information on the modes of vibration as well as amplification and deamplification effects on different parts of the edifice. The ground motion records were analyzed using three different methods:comparisons of peak ground accelerations (PGA), power spectral density analysis (PSD), and standard spectral ratio analysis (SSR). Time and frequency domain analyses show that site amplification is concentrated along the elongated crest of the edifice where amplifications of up to 1100 % were measured relative to the motion at the flat base. Theoretical calculations and frequency analyses of field data indicate a maximum response along the ridge crest of Little Red Hill for frequencies of about 5 Hz, which correlate to wavelengths approximately equal to the half-width or height of the edifice (~240 m). The consequence of amplification effects on the stability and degradation of rock masses can be seen: areas showing high amplification effects overlap with the spatial distribution of seismogenic block fields at Little Red Hill. Additionally, a laboratory-scale (1:1,000) physical model was constructed to investigate the effect of topographic amplification of ground motion across a mountain edifice by simulating the situation of the Little Red Hill field experiment in a smallscale laboratory environment. The laboratory results show the maximum response of the model correlates to the fundamental mode of vibration of Little Red Hill at approximately 2.2 Hz. It is concluded that topography, geometry and distance to the seismic source, play a key role causing amplification effects of seismic ground motion and degradation of rock mass across bedrock-dominated mountain edifices.
47
Isbiliroglu, Levent. "Strategy for Selecting Input Ground Motion for Structural Seismic Demand Analysis." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAU009/document.
Full textAbstract:
Les signaux accélérométriques enregistrés lors de l’occurrence d’un événement sismique est très large présentent une forte variabilité, par conséquent ils ne sont pas utilisé dans les analyse dynamiques de tenue sismique des structures. En effet, l’utilisation des accélérogrammes réels, pour les analyses dynamiques non linéaires, s’avère couteuse en termes de temps de calcul. La pratique courante prévoit la minimisation (voir suppression) de telle variabilité, mais les conséquences d’une telle opération sur la réponse des structures ne sont pas clairement indiquées. L’étude ci-présente a pour scope la quantification de l’impact des méthodes de sélection qui gardent la variabilité du signal sur les résultats de l’analyse de la réponse des structures (exprimée en termes d’engineering demand parameters EDPs). En particulier les questions suivantes seront investiguées :Quel est le niveau de variabilité des accélérogrammes réels et comment ce niveau est modifié par les techniques couramment utilisées ?Quelle est l’impact de la variabilité sur la réponse de plusieurs types de structures ?Pour un scénario sismique donné, un spectre cible est défini à partir de plusieurs équation de prédiction du mouvement sismique, sélection parmi celles disponibles en littérature. Les accélérogrammes sont sélectionnés à partir de quatre familles d’accélérogrammes, chacune relative à une méthode de modification : réels (enregistrés); mise à l’échelle (multiplication, par un facteur) ; calés aux spectres cibles avec large tolérance ; calés aux spectres cibles dans une plage de tolérance étroite.Chaque jeu de signaux est composé de cinq accélérogrammes et la sélection des signaux est faite en tenant compte de deux sources de variabilité : la variabilité au sein de chaque jeu de données (intraset), et la variabilité entre les différents jeux de données (interset) tous compatibles avec le même spectre cible. Les tests sur les EDPs menés sur les signaux accélérométriques réels mènent à la quantification de la variabilité naturelle (pour le scénario considéré). Les analyses basées sur les signaux réels sont utilisés comme benchmark afin d’évaluer non seulement de combien la distribution des EDPs (en termes de valeur moyenne et variabilité) est réduite par les différentes méthodes testées, mais aussi d’évaluer l’impact des choix de l’équation de prédiction du mouvement, des plages de tolérance, du nombre d’accélérogrammes constituant chaque jeu, du nombre de jeux, de le scope de l’analyse structurale et le modèle de structure.Ce travaille nous conduit à conclure que un seul jeu d’accélérogramme, tel qu’utilisé dans la pratique courante, est insuffisant pour assurer le niveau d’EDPs indépendamment de la méthode de modification utilisés, cela est lié à la variabilité des signaux et entre les jeux d’accélérogrammes. Les signaux réels, compatibles avec le spectre définis pour le scénario sismique, are l’option plus réaliste pour l’analyse dynamique non-linéaire ; si une méthode de modification du signal est nécessaire, la plus adaptées dépend du scope de l’analyse spectrale et du modèle. Le choix de l’équation de prédiction du mouvement sismique utilisée pour définir le spectre cible impacte significativement les caractéristiques des mouvements sismiques et des EDPs. Cette observation ne dépend pas de la stratégie de de modification du signalThe observed variability is very large among natural earthquake records, which are not consolidated in the engineering applications due to the cost and the duration. In the current practice with the nonlinear dynamic analysis, the input variability is minimized, yet without clear indications of its consequences on the output seismic behavior of structures. The study, herein, aims at quantifying the impact of ground motion selection with large variability on the distribution of engineering demand parameters (EDPs) by investigating the following questions:What is the level of variability in natural and modified ground motions?What is the impact of input variability on the EDPs of various structural types?For a given earthquake scenario, target spectra are defined by ground motion prediction equations (GMPEs). Four ground motion modification and selection methods such as (1) the unscaled earthquake records, (2) the linearly scaled real records, (3) the loosely matched spectrum waveforms, and (4) the tightly matched waveforms are utilized. The tests on the EDPs are performed on a record basis to quantify the natural variability in unscaled earthquake records and the relative changes triggered by the ground motion modifications.Each dataset is composed by five accelerograms; the response spectrum compatible selection is then performed by considering the impact of set variability. The intraset variability relates to the spectral amplitude dispersion in a given set, and the interset variability relates to the existence of multiple sets compatible with the target.The tests on the EDPs are performed on a record basis to quantify the natural variability in unscaled earthquake records and the relative changes triggered by the ground motion modifications. The distributions of EDPs obtained by the modified ground motions are compared to the observed distribution by the unscaled earthquake records as a function of ground motion prediction equations, objective of structural analysis, and structural models.This thesis demonstrates that a single ground motion set, commonly used in the practice, is not sufficient to obtain an assuring level of the EDPs regardless of the GMSM methods, which is due to the record and set variability. The unscaled real records compatible with the scenario are discussed to be the most realistic option to use in the nonlinear dynamic analyses, and the ‘best’ ground motion modification method is demonstrated to be based on the EDP, the objective of the seismic analysis, and the structural model. It is pointed out that the choice of a GMPE can provoke significant differences in the ground motion characteristics and the EDPs, and it can overshadow the differences in the EDPs obtained by the GMSM methods
48
Fitoz, Hatice Eda. "Response Of Asymmetric Isolated Buildings Under Bi-directionalexcitations Of Near-fault Ground Motions." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614121/index.pdf.
Full textAbstract:
Isolator displacements, floor accelerations, roof displacements, base shear and
torsional moments are basic parameters that are considered in the design of
seismically isolated structures. The aim of this study is to evaluate the effects of bidirectional
earthquake excitations of near fault records on the response of base
isolated structures in terms of basic parameters mentioned above. These parameters
computed from nonlinear response history analysis (RHA) and they are compared
with the parameters computed from equivalent lateral force procedure (ELF). Effect
of asymmetry in superstructure is also examined considering mass eccentricity at
each floor level. Torsional amplifications in isolator displacements, floor
accelerations, roof displacements and base shear are compared for different level of
eccentricities. Two buildings with different story heights are used in the analyses.The building systems are modeled in structural analysis program SAP2000. The
scaling of ground motion data are taken from the study of &ldquoResponse of Isolated Structures Under Bi-directional Excitations of Near-fault ground Motions&rdquo
(Ozdemir, 2010). Each ground motion set (fault normal and fault parallel) are applied simultaneously for different range of effective damping of lead rubber bearing (LRB) and for different isolation periods.
49
Tsinias, Vasileios. "A hybrid approach to tyre modelling based on modal testing and non-linear tyre-wheel motion." Thesis, Loughborough University, 2014. https://dspace.lboro.ac.uk/2134/17852.
Full textAbstract:
The current state-of-the-art tyre models tend to be demanding in parameterisation terms, typically requiring extensive and expensive testing, and computational power. Consequently, an alternative parameterisation approach, which also allows for the separation of model fidelity from computational demand, is essential. Based on the above, a tyre model is introduced in this work. Tyre motion is separated into two components, the first being the non-linear global motion of the tyre as a rigid body and the second being the linear local deformation of each node. The resulting system of differential equations of motion consists of a reduced number of equations, depending on the number of rigid and elastic modes considered rather than the degrees of freedom. These equations are populated by the eigenvectors and the eigenvalues of the elastic tyre modes, the eigenvectors corresponding to the rigid tyre modes and the inertia properties of the tyre. The contact sub-model consists of bristles attached to each belt node. Shear forces generated in the contact area are calculated by a distributed LuGre friction model while vertical tread dynamics are obtained by the vertical motion of the contact nodes and the corresponding bristle stiffness and damping characteristics. To populate the abovementioned system of differential equations, the modal properties of the rigid and the elastic belt modes are required. In the context of the present work, rigid belt modes are calculated analytically, while in-plane and out-of-plane elastic belt modes are identified experimentally by performing modal testing on the physical tyre. To this end, the eigenvalue of any particular mode is obtained by fitting a rational fraction polynomial expression to frequency response data surrounding that mode. The eigenvector calculation requires a different approach as typically modes located in the vicinity of the examined mode have an effect on the apparent residue. Consequently, an alternative method has been developed which takes into account the out-of-band modes leading to identified residues representing only the modes of interest. The validation of the proposed modelling approach is performed by comparing simulation results to experimental data and trends found in the literature. In terms of vertical stiffness, correlation with experimental data is achieved for a limited vertical load range, due to the nature of the identified modal properties. Moreover, the tyre model response to transient lateral slip is investigated for a range of longitudinal speeds and vertical loads, and the resulting relaxation length trends are compared with the relevant literature.
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Alsaleem, Fadi M. "An investigation into the effect of the PCB motion on the dynamic response of MEMS devices under mechanical shock loads." Diss., Online access via UMI:, 2007.
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