Дисертації з теми "Stance prediction"
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Ruggeri, Federico. "Predizione della struttura di un argomento con feature di stance classification." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/15009/.
Повний текст джерелаWojatzki, Michael Maximilian [Verfasser], and Torsten [Akademischer Betreuer] Zesch. "Computer-assisted understanding of stance in social media : formalizations, data creation, and prediction models / Michael Maximilian Wojatzki ; Betreuer: Torsten Zesch." Duisburg, 2019. http://d-nb.info/1177681471/34.
Повний текст джерелаLeeTiernan, Scott. "Modeling and predicting stable response variation across situations /." Thesis, Connect to this title online; UW restricted, 2002. http://hdl.handle.net/1773/9076.
Повний текст джерелаBingham, Jeffrey Thomas. "A framework to quantify neuromechanical contributions to stable standing balance: Modeling predictions and experimental observations." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/52161.
Повний текст джерелаChevalier, Samuel Chapman. "Inference, estimation, and prediction for stable operation of modern electric power systems." Thesis, Massachusetts Institute of Technology, 2021. https://hdl.handle.net/1721.1/130842.
Повний текст джерелаCataloged from the official PDF of thesis.
Includes bibliographical references (pages 261-277).
To keep pace with social-ecological disruptions and technological progressions, electrical power systems must continually adapt. In order to address the stability-related challenges associated with these adaptations, this thesis develops a set of analytically rigorous yet practically oriented methods for ensuring the continued stability of modern power systems. By leveraging inference, estimation, and predictive modeling techniques, the proposed methods capitalize on the unprecedented amount of real time data emerging from modernizing smart grids. For each method, we provide simulated test results from IEEE benchmark systems. Newly deployed Phasor Measurement Units (PMUs) are observing the presence of detrimental low frequency forced oscillations (FOs) in transmission grid networks. To begin this thesis, we address the problem of locating the unknown sources of these FOs.
To perform source identification, we develop an equivalent circuit transformation which leverages suitably constructed transfer functions of grid elements. Since FO sources appear in this equivalent circuit as independent current injections, a Bayesian framework is applied to locate the most probable source of these injections. Subsequently, we use our equivalent circuit to perform a systematic investigation of energy-based source identification methods. We further leverage this equivalent circuit transformation by developing "plug-and-play" stability standards for microgrid networks that contain uncertain loading configurations. As converter-based technology declines in cost, microgrids are becoming an increasingly feasible option for expanding grid access. Via homotopic parameterization of the instability drivers in these tightly regulated systems, we identify a family of rotational functions which ensure that no eigenmodes can be driven unstable.
Any component which satisfies the resulting standards can be safely added to the network, thus allowing for plug-and-play operability. High-fidelity linearized models are needed to perform both FO source identification and microgrid stability certification. Furthermore, as loss of inertia and real-time observability of grid assets accelerate in tandem, real-time linearized modeling is becoming an increasingly useful tool for grid operators. Accordingly, we develop tools for performing real-time predictive modeling of low frequency power system dynamics in the presence of ambient perturbations. Using PMU data, we develop a black-box modeling procedure, known as Real-Time Vector Fitting (RTVF), that takes explicit account for initial state decay and concurrently active input signals. We then outline a proposed extension, known as stochastic-RTVF, that accounts for the corrupting effects of unobservable stochastic inputs.
The surrogate modeling utilized by vector fitting can also be applied to the steady state power flow problem. Due to an unprecedented deployment of distributed energy resources, operational uncertainty in electrical distribution networks is increasing dramatically. To address this challenge, we develop methodology for speeding up probabilistic power flow and state estimation routines in distribution networks. We do so by exploiting the inherently low-rank nature of the voltage profile in these systems. The associated algorithms dynamically generate a low-dimensional subspace which is used to construct a projection-based reduced order model (ROM) of the full nonlinear system. Future system solves using this ROM are highly efficient.
by Samuel Chapman Chevalier.
Ph. D. in Mechanical Engineering and Computation
Ph.D.inMechanicalEngineeringandComputation Massachusetts Institute of Technology, Department of Mechanical Engineering
Handl, Tomáš. "Algoritmus Vivaldi pro nalezení pozice stanice v Internetu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-218110.
Повний текст джерелаWangerin, Spencer D. "Development and validation of a human knee joint finite element model for tissue stress and strain predictions during exercise." DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/1129.
Повний текст джерелаVerde, Joshua A. "Lake Powell Food Web Structure: Predicting Effects of Quagga Mussel." BYU ScholarsArchive, 2017. https://scholarsarchive.byu.edu/etd/6702.
Повний текст джерелаOh, Yunje. "Prediction of steady state response in dynamic mode atomic force microscopy and its applications in nano-metrology." The Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=osu1135222817.
Повний текст джерелаHopf, Konstantin [Verfasser], and Thorsten [Akademischer Betreuer] Staake. "Predictive Analytics for Energy Efficiency and Energy Retailing / Konstantin Hopf ; Betreuer: Thorsten Staake." Bamberg : University of Bamberg Press, 2019. http://d-nb.info/1191183580/34.
Повний текст джерелаVedin, Ola. "Prevalence and Prognostic Impact of Periodontal Disease and Conventional Risk Factors in Patients with Stable Coronary Heart Disease." Doctoral thesis, Uppsala universitet, Institutionen för medicinska vetenskaper, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-260564.
Повний текст джерелаOesting, Marco [Verfasser], Martin [Akademischer Betreuer] Schlather, and Robert [Akademischer Betreuer] Schaback. "Spatial Interpolation and Prediction of Gaussian and Max-Stable Processes / Marco Oesting. Gutachter: Martin Schlather ; Robert Schaback. Betreuer: Martin Schlather." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2012. http://d-nb.info/1042970890/34.
Повний текст джерелаAsiimwe, Alex. "Morbidity and mortality in patients with stable and unstable COPD : construction and validation of a prediction model using routinely collected data." Thesis, University of Portsmouth, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.478895.
Повний текст джерелаStange, Michael [Verfasser], and Albrecht E. [Akademischer Betreuer] Melchinger. "QTL mapping and genomic prediction of complex traits based on high-density genotyping in multiple crosses of maize (Zea mays L.) / Michael Stange. Betreuer: Albrecht E. Melchinger." Hohenheim : Kommunikations-, Informations- und Medienzentrum der Universität Hohenheim, 2013. http://d-nb.info/1045276243/34.
Повний текст джерелаGembiczká, Adriana. "Analýza trhu bydlení pro seniory: stane se zajištění sociálních služeb v oblasti bydlení pro seniory podnikatelským cílem budoucnosti?" Master's thesis, Vysoká škola ekonomická v Praze, 2011. http://www.nusl.cz/ntk/nusl-125200.
Повний текст джерелаEdwards, Keith. "A proposed methodology for predicting the carbon and nitrogen stable isotope measures of K'inich Yax K'uk Mo', Copan dynastic founder." Master's thesis, University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4887.
Повний текст джерелаID: 030423403; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (M.A.)--University of Central Florida, 2011.; Includes bibliographical references (p. 72-79).
M.A.
Masters
Anthropology
Sciences
Gunaratnam, Bakeerathan. "TOPICS IN STOCHASTICS AND STATISTICS: SHOCK CREATION AND DISSOLUTION FOR STABLE AND LINNIK CONSERVATION LAWS AND TARGET STUDENT RECRUITMENT USING PREDICTIVE MODELING." Case Western Reserve University School of Graduate Studies / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=case1363709622.
Повний текст джерелаŠvéda, Jaroslav. "Nalezení pozice stanic v Internetu pomocí umělých souřadnicových systémů." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-218001.
Повний текст джерелаLi, Yuan. "Computational Methods for Analyzing RNA Folding Landscapes and its Applications." Doctoral diss., University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5400.
Повний текст джерелаID: 031001558; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Adviser: Shaojie Zhang.; Title from PDF title page (viewed August 26, 2013).; Thesis (Ph.D.)--University of Central Florida, 2012.; Includes bibliographical references (p. 132-140).
Ph.D.
Doctorate
Computer Science
Engineering and Computer Science
Computer Science
Škvor, Martin. "Lokalizace stanic v síti Internet pomocí umělých souřadnicových systémů." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2010. http://www.nusl.cz/ntk/nusl-218229.
Повний текст джерелаKahaei, Mohammad Hossein. "Performance analysis of adaptive lattice filters for FM signals and alpha-stable processes." Thesis, Queensland University of Technology, 1998. https://eprints.qut.edu.au/36044/7/36044_Digitised_Thesis.pdf.
Повний текст джерелаBrogno, Luigi. "Nocturnal low-level jets over complex terrain: driving mechanisms and analytical modeling." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/20539/.
Повний текст джерелаBalzotti, Christopher Stephen. "Multidisciplinary Assessment and Documentation of Past and Present Human Impacts on the Neotropical Forests of Petén, Guatemala." BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2129.
Повний текст джерелаAmey, Katherine Springer. "Hydrology And Predictive Model Of Headwater Streams And The Groundwater/Surface Water Interactions Supporting Brook Trout Habitat In Northeast Ohio." Kent State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=kent1301618586.
Повний текст джерелаGrecian, William James. "Factors influencing the marine spatial ecology of seabirds : implications for theory, conservation and management." Thesis, University of Plymouth, 2011. http://hdl.handle.net/10026.1/873.
Повний текст джерела(7460849), Aldo Fabrizio Porco. "USING MODULAR ARCHITECTURES TO PREDICT CHANGE OF BELIEFS IN ONLINE DEBATES." Thesis, 2019.
Знайти повний текст джерелаResearchers studying persuasion have mostly focused on modeling arguments to understand how people’s beliefs can change. However, in order to convince an audience the speakers usually adapt their speech. This can be seen often in political campaigns when ideas are phrased - framed - in different ways according to the geo-graphical region the candidate is in. This practice suggests that, in order to change people’s beliefs, it is important to take into account their previous perspectives and topics of interest.
In this work we propose ChangeMyStance, a novel task to predict if a user would change their mind after being exposed to opposing views on a particular subject. This setting takes into account users’ beliefs before a debate, thus modeling their preconceived notions about the topic. Moreover, we explore a new approach to solve the problem, where the task is decomposed into ”simpler” problems. Breaking the main objective into several tasks allows to build expert modules that combined produce better results. This strategy significantly outperforms a BERT end-to-end model over the same inputs.
Stanke, Mario [Verfasser]. "Gene prediction with a hidden Markov model / vorgelegt von Mario Stanke." 2004. http://d-nb.info/970841310/34.
Повний текст джерелаOesting, Marco. "Spatial Interpolation and Prediction of Gaussian and Max-Stable Processes." Doctoral thesis, 2012. http://hdl.handle.net/11858/00-1735-0000-000D-F069-0.
Повний текст джерелаTi-ChenYeh and 葉廸珺. "Establishing A Stable and Loyal Customers Prediction Model with Bootstrap." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/7ks9c9.
Повний текст джерелаHofacker, I. L., B. Priwitzer, and P. F. Stadler. "Prediction of locally stable RNA secondary structures for genome-wide surveys." 2004. https://ul.qucosa.de/id/qucosa%3A32116.
Повний текст джерелаTung, Chi-Feng, and 董其豐. "Mobility Prediction-Based Relay Selection Scheme for Stable Connections in VANETs." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/05103792050876499135.
Повний текст джерела國立中央大學
資訊工程研究所
99
Vehicular ad hoc network (VANET) is a novel class of wireless network. Vehicles implemented with on board unit (OBU), which can communicate with each other by vehicle-to-vehicle (V2V) and vehicle to infrastructure (V2R) network architecture. In the V2V network environment, vehicular network topology is changing dynamically all the time with high mobility, the communications occurred in this architecture is intermittent pattern. To solve this problem, numerous researchers have proposed different kinds of VANET routing protocol to enhance the success of packets delivery ratio through choosing the path with high density. After determining the routing path, the choosing of relay nodes usually follow the mobile ad hoc networks (MANETs) routing protocol, that is, it selects the closest node with the destination or consider the power supply and computation ability of node. However, In MANET, mobile nodes are moving in a random and irregular pattern hence, it is very hard to predict their movements. Unlike unpredictable mobility in MANET, vehicles are limited by predefined road segments, traffic rules and driver behaviors. Furthermore, nowadays Vehicular on board units are able to equip a much more powerful vehicle rechargeable battery and a larger volume of communication device than before; therefore, it becomes inappropriate to take power supply volume and computing into account. Therefore, it is unsuitable to determine the relay node by these terms. What’s more important is that the vehicle moves too fast to make the relay node easily to leave the transmission range of sender, as a result, it wastes a lot of network bandwidth for route maintenance and re-discovery. In order to solve the above mentioned problems, this thesis proposed a mobility prediction-based relay selection scheme for stable connections in VANETs which takes both direction of vehicles and routing path into account. It makes packet routing and vehicles keep moving in the same direction, for reducing the link disconnection. This thesis takes GPS errors into consideration when determining the lane position to predict the vehicles mobility, for a even more accurate mobility prediction. Finally, the proposal is examined by the conducted simulation— the simulation results show that the proposed mechanism, on average, can increase connecting time by 25.6% but decrease number of link disconnection by 20.2%; furthermore, the prediction accuracy of connecting time is improved within the absolute error of 5.09%. This proves that in the multi-lanes scenarios, the proposed mechanism can provide even more stable connecting time than others.
Wu, De-Wei, and 武德偉. "Prediction of stable limit cycles in feedback bilinear systems:Bellman-Gronwall Inequality." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/53987709200160653334.
Повний текст джерела義守大學
電機工程學系
91
Limit cycles are unique phenomenon of nonlinear networks and have been a main concern of the researchers over the years. Prediction of limit cycles is very significant, because limit cycles can happen in any kind of physical system. In this thesis, the existence of limit cycles for a class of feedback bilinear systems is explored. Using the Bellman-Gronwall inequality, not only the exponentially stable limit cycles phenomenon of such systems can be guaranteed but also the oscillation behaviors of such systems can be correctly predicted. Finally, some numerical examples is provided to illustrate the use of the main result.
Ralhan, Sameer. "Robust model predictive control of stable and integrating linear systems." Thesis, 2000. http://hdl.handle.net/1911/19549.
Повний текст джерелаCHANG, YA-LING, and 張雅羚. "Adaptive Stable Generalized Predictive Temperature Control for Air Conditioning System." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/52338199575334726641.
Повний текст джерела國立中興大學
電機工程學系
91
This thesis aims at developing methodologies and techniques for adaptive stable generalized predictive control of small air conditioning systems. Such techniques are used to control the rotational speed of pump of ice-water machine of small air-condition system with air-cooling, thereby adjusting the rate of heat exchange for the cold store in a refrigerated circulatory system in order to accomplish temperature set-point tracking. To achieve satisfactory temperature control performance, two predictive control strategies, adaptive stable generalized predictive control and adaptive stable generalized predictive control with fuzzy modeling, are proposed. Computer simulations for several industrial processes and experimental results of temperature control in the air-condition system show that both the two proposed control methods have been proven to be capable of stability, disturbance rejection capability and good tracking performance.
葉雲碩. "Stable Predictive Control for an AC Induction Motor-Driven Servo System." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/76690187743309866281.
Повний текст джерела國立中興大學
機械工程學系
92
This thesis considers the system identification and infinite horizon stable predictive control (IHSPC) design for an AC induction motor-driven servo system. The RLS (recursive least squares) algorithm is used for obtaining the optimal parameters of a discrete-time linear estimation model with a constant bias term. Based on the estimated model, the IHSPC design methodology is adopted for synthesizing a stable predictive control law for the actual servo system. Finally, the control law is developed in the MATLAB/SIMULINK environment and implemented using a dSPACE DS1102 control board. Experimental results validate the feasibility of the suggested approach.
Liu, Shu Chen, and 劉淑貞. "The Stable Regions of Multi-Block Predictor-Corrector Method for ODE's." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/75407656621700670775.
Повний текст джерела國立中正大學
數學研究所
91
The multi-block predictor-corrector method(BPC) is one of the efficient and accurate method for solving the numerical solution of the ordinary differential equations. By choosing some suitable matrix coefficients in two schemes with repeated self-correcting processes, P(EC)^nE,n=1,2,...,we investigate and compare the corresponging changes of the stable regions. We also vary the coefficients matrix in the local truncation error to study the responses about the stable respectively.
Lin, Shu-Kai, and 林書楷. "Unified Predictive Control Applied to Stable First-Order-Plus-Dead-Time Processes." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/66639704776612243853.
Повний текст джерела國立交通大學
機械工程學系
98
In the field of the motion control, dead-time process with model uncertainty and disturbance are widely studied because of the practical importance. This thesis is divided into two parts to deal with these problems, respectively; Part I (based on the concept of robust control): One applies Unified Predictive Control (UPC) to first-order-plus-dead-time (FOPDT) stable processes with concerns of model uncertainty and deterministic disturbance, and analyzed the robustness and nominal performance of the system. A simple and useful parameter tuning method is proposed. The results of this part guarantees optimal nominal performance based on robust stable condition. Part II (based on the concept of adaptive control): one proposes an Adaptive Unified Predictive Control (Adaptive-UPC) and applied it to first-order-plus-dead-time (FOPDT) process model to eliminate effects of model uncertainties and unknown deterministic disturbance. This new control structure is designed based on one of the concepts of adaptive control, Indirect Self-tuning Regulator, and constructed by combining UPC controller, Recursive Least-Squares Estimation with forgetting factor (RLS with forgetting factor) and Variable Regression Estimation (VRE). The results of this part can be effectively used to first-order-plus-dead-time (FOPDT) process models and can accurately estimate the process parameters (gain, time constant and dead-time) with elimination of unknown deterministic disturbance. For practical purpose, the problem of measurement noise must be concerned. Therefore the Modified Adaptive Unified Predictive Control (Modified Adaptive-UPC) is proposed to decrease the effect caused by measurement noise.
ZHU, MU-FENG, and 朱穆鳳. "On stable algorithm of block predictor-corrtctor method for five-CPU computers." Thesis, 1992. http://ndltd.ncl.edu.tw/handle/90819929001981379027.
Повний текст джерелаAdnan, Adnan. "Evaluation of near infrared spectroscopy for prediction of quality attributes and authentication of green coffee beans." Doctoral thesis, 2017. http://hdl.handle.net/21.11130/00-1735-0000-0005-14B3-A.
Повний текст джерелаOliveira, Henrique Martim Aguiar Sobral. "Bitcoin price movement direction prediction : a comparison between Decision Tree SVM and LSTM." Master's thesis, 2021. http://hdl.handle.net/10400.14/35339.
Повний текст джерелаEsta tese explora a capacidade dos métodos de machine learning em conjunto com o uso de características da blockchain, um proxy de stable coins e indicadores técnicos para prever corretamente o movimento do preço da Bitcoin. Esta tese tenta provar que modelos de machine learning podem superar uma estratégia Buy & Hold com as variáveis selecionadas e compara o desempenho de uma árvore de decisão, uma SVM e uma rede neural recorrente LSTM. Os resultados da seleção de variáveis apoiam a literatura existente. Além disso, os resultados também sugerem que a dificuldade de mineração e características do blockchain relacionadas com atividade transacional podem fornecer informações complementares sobre a Bitcoin. Em termos de desempenho dos modelos, os resultados mostraram que o modelo de árvore de decisão tem predisposição para sobre ajustar devido à sua baixa complexidade e ao tipo de dados. Os resultados do SVM mostraram que, embora tenha alcançado a maior precisão, apenas conseguiu identificar a tendência geral e, portanto, não foi capaz de superar a estratégia Buy & Hold. Mesmo que o LSTM não tenha superado os benchmarks, foi o modelo que mostrou os resultados mais promissores, e seu desempenho provavelmente melhoraria realizando ajuste adicional dos híper-parâmetros. Logo, a incapacidade de superar o benchmark não foi conclusivo. Finalmente, o facto de o modelo de regressão logística ter sido capaz de superar a estratégia Buy & Hold em termos de retornos e volatilidade, leva-nos a concluir que machine learning pode ser eficaz na previsão da Bitcoin com as variáveis selecionadas.
Chang, Chih-Peng, and 張志鵬. "Control of stable and integrating processes with dead-time based on PDOB and Smith predictor structure." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/10971257948311630919.
Повний текст джерела國立交通大學
機械工程系所
98
Significantly the dead-time has a great influence on the stability of systems, which make the process more difficult to control. Therefore, this thesis presents a discrete dead-time compensator to improve the performance and capability of disturbance rejection for dead-time systems. It applied predictive DOB and Smith predictor structure to compensate output delay and input disturbance for stable and integrating plants. The proposed structure consists of two parts: the inner loop and the outer loop. Firstly the PDOB can be designed to reject any kind of deterministic disturbances, including step disturbance, ramp disturbance and sine disturbance. Also, the property of DOB structure can approach the real plant to the nominal plant. The PDOB based on DOB structure has an additional predictive filter, which eliminate the time delay of estimated disturbance. Because of the property enhances disturbance rejection performance of traditional DOB for dead-time systems especially for periodic disturbance. Secondly, the Smith predictor structure is capable to suppress the effects of time delay. Seeing that the stability is influenced by the model mismatch and model mismatch will always exist in the process. In this thesis, we propose a robust controller which compensates the effect of time delay and reject deterministic disturbance to satisfy the robust stability.
Bade, Darren Lee. "Predicting stable isotope signatures of dissolved inorganic carbon in lakes models to aid in the understanding of carbon cycling across many lakes /." 2002. http://catalog.hathitrust.org/api/volumes/oclc/51552605.html.
Повний текст джерелаTypescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 26-31).
Schauble, Edwin Arthur. "I. Predicting equilibrium stable isotope fractionations of iron, chlorine, and chromium. II. Oxygen-isotope investigation of mesozoic and cenozoic granitoids of the northeastern Great Basin, Nevada and Utah." Thesis, 2002. https://thesis.library.caltech.edu/6899/1/Schauble_ea_2002.pdf.
Повний текст джерелаTheoretical studies of the stable isotope geochemistry of iron, chlorine, and chromium are presented, with the goal of providing a framework to aid interpretations of new measurements and to identify promising areas for future study. In addition, new oxygen-isotope measurements of Mesozoic and Cenozoic granitoids from the northeastern Great Basin are used to constrain the temporal evolution of magmatic sources in the region.
The stable isotope compositions of elements heavier than sulfur (atomic no. 16) are generating great geochemical interest, now that new mass-spectrometry techniques make it possible to measure their isotopic abundances with high precision. Theoretical calculations for three of these elements (iron, chlorine, and chromium) are made using published infrared, Raman, and inelastic neutron scattering measurements of vibrational frequencies, in combination with empirical and ab initio force-field estimates of unknown frequencies. The calculations suggest that a number of natural processes can drive significant stable isotope fractionations of heavy elements, including oxidation/reduction during the precipitation or dissolution of dissolved metals (inorganically or organically), and bond-partner exchange during hydrothermal alteration, or degradation of Cl-bearing organic compounds. At equilibrium and 25°C, ^(56)Fe/^(54)Fe will be ~5‰ higher in [Fe(H_2O)_6]^(3+) than in coexisting [Fe(H_2O)_6]^(2+), ^(53)Cr/^(52)Cr will be ~6-7‰ higher in [CrO_4]^(2-) than in coexisting [Cr(H_2O)_6]^(3+) or Cr_2O_3, and aqueous Cl- will be ~2-3‰ lighter than coexisting alteration minerals like mica and amphibole.
Oxygen isotope measurements of whole-rock samples from granitoid plutons in the northeastern Great Basin suggest that two or three different types of source rocks were melted in varying proportions during the three stages of magmatism in this region in the Late Jurassic, Late Cretaceous, and mid-Cenozoic. Radiogenic-isotope measurements were previously made on the same samples. Late Cretaceous (90-70 Ma) granites have high δ^(18)O (+9.3 to + 12.1) and ^(87)Sr/^(86)Sr_i (0.711 to 0.734), and low εNd (-13 to -23) indicating that their source was dominated by evolved crustal sediments and basement. However, late Jurassic plutons in this region span a larger range of δ^(18)O values (+7.2 to + 13.2), despite having Sr and Nd isotopic compositions that are much less suggestive of an ancient crustal component (^(87)Sr/^(86)Sr_i = 0.705 to 0.711, εNd = -2.5 to -6.5) than the Late Cretaceous plutons, suggesting moderate to extensive mixing or assimilation of high-δ^(18)O sedimentary rocks into a more mafic parent melt. The 40-25 Ma Cenozoic plutons (δ^(18)O = +7.0 to + 9.7, ^(87)Sr/^(86)Sr_i = 0.707 to 0.717, εNd= -13.2 to -26.3) probably have a source dominated by continental basement. The Cenozoic plutons can be subdivided into a higher δ^(18)O (+8.6 to + 9.7) southern group and a lower δ^(18)O (+7.0 to + 8.2) northern group across a Crustal Age Boundary (CAB) at roughly 40° 40' N; this CAB coincides with a radiogenic isotope boundary defined with the same samples, as well as with the approximate southern limit of exposure of Archean basement. The low δ^(18)O values and depleted lead isotope compositions of the Lower Array (northern) samples indicate that Archean age basement is present beneath a large area of the most northeasterly part of the Great Basin. A further, speculative conclusion is that δ^(18)O of the (meta)sedimentary source region may have dropped by 2-3‰ as a result of fluid-rock interaction sometime between the Jurassic and Late Cretaceous magmatic episodes.
Cuinala, Hildair Panfílio Mendes de Carvalho. "Previsão numérica da vida à fadiga em peças entalhadas sujeitas a cargas cíclicas multiaxiais." Master's thesis, 2019. http://hdl.handle.net/10316/93623.
Повний текст джерелаA fadiga é na grande maioria das vezes a razão associada a ruína dos componentes mecânicos solicitados ciclicamente. Este fenómeno é fortemente influenciado por várias propriedades, das quais destacamos a geometria do material solicitado e o tipo de carregamento aplicado. Quanto maior for a descontinuidade geométrica apresentada no material maior a sua sensibilidade ao fenómeno de fadiga.Atualmente a grande maioria dos componentes mecânicos utilizados nas transmissões mecânicas, apresentam várias descontinuidades geométricas severas e estão sujeitos a carregamentos combinados e cíclicos, implicando elevada sensibilidade a falha por fadiga. Salientamos que muitas das vezes é inevitável a presença das descontinuidades geométricas, uma vez que, podem nascer por necessidades de projeto, por questões funcionais, ambientais ou orçamentais.Visando os aspetos listados no parágrafo anterior, neste estudo pretendemos desenvolver uma metodologia de previsão de vida à fadiga para peças de secção circular sujeitas a histórias de cargas multiaxiais. Para tal utilizamos a liga de aço martensítico de alta resistência DIN 34CrNiMo6, que apresenta elevada ductilidade e tenacidade, bem como tem grande destaque no sector automóvel e aeronáutico. Não podemos deixar de referir, que quanto maior a complexidade do carregamento aplicado, maior é a dificuldade do método em prever a falha por fadiga, o que torna o estudo bastante elaborado pois estamos presentes a carregamentos proporcionais multiaxiais, considerados para duas relações entre momento fletor (B) e momento torsor (T), (B=2T e B=T) e três ângulos de aplicação do momento fletor relativamente à raiz do entalhe (0º, 45º e 90º).O estudo procedeu-se em três fases, sendo que na primeira fase determinamos os estados de tensão e de deformação nas zonas críticas das descontinuidades geométricas, obtidos a partir de modelos numéricos elasto-plásticos. Nesta fase foi estimada a vida de fadiga usando o modelo energético de Ellyin e que posteriormente foi comparada com os resultados obtidos em trabalhos anteriores pelo método de Glinka.Numa segunda fase, as previsões numéricas foram comparadas com resultados experimentais, de fadiga oligocíclica, obtidos para as mesmas condições de serviço.Por fim, fizemos uma análise dos resultados apurados para cada modelo de previsão e repararmos que os mesmos são satisfatórios, pois 88,9% dos resultados encontram-se no regime conservativo e os que não estão dentro desta zona estão localizados nos intervalos de dispersão propostos.
Fatigue is most often the reason associated with the failure of cyclically ordered mechanical components. This phenomenon is strongly influenced by several properties, of which we highlight the geometry of the material requested and the type of loading applied. The greater the geometric discontinuity presented in the material, the greater its sensitivity to the phenomenon of fatigue.Currently, the vast majority of mechanical components used in mechanical transmissions have several severe geometric discontinuities and are subject to combined and cyclic loading, implying high sensitivity to fatigue failure. We emphasize that often the presence of geometric discontinuities is inevitable since they can be born due to project needs, functional, environmental or budgetary issues.Aiming at the aspects listed in the previous paragraph, in this study we intend to develop a fatigue life prediction methodology for circular section parts subjected to multiaxial load histories. For this, we use the high strength martensitic alloy steel DIN 34CrNiMo6, which high ductility and toughness, as well as being prominent in the automotive and aeronautics sector. We can not fail to mention that the greater the complexity of loading applied, the greater the difficulty of the method to predict fatigue failure, which makes the study quite elaborate because we are present with multiaxial proportional loads, considered for two relationships between bending moment. (B) and torsional moment (T), (B = 2T and B = T) and three angles of application of the bending moment relative to the notch root (0º, 45º and 90º).The study proceeded in three phases, and in the first phase we determined the stress and strain states in the critical zones of geometric discontinuities, obtained from elastoplastic numerical models. In this phase, the fatigue life was estimated using the Ellyin energy model and later compared with the results obtained in previous works by the Glinka method.In the second phase, the numerical predictions were compared with experimental oligocyclic fatigue results obtained for the same service conditions.Finally, we made an analysis of the results obtained for each prediction model and noticed that they are satisfactory because 88.9% of the results are in the conservative regime and those that are not within this zone are located in the proposed dispersion intervals.
Van, der Walt Koert Nicolaas. "Selected anthropometric, physical and motor performance predictors of lower body explosive power in adolescents : the PAHL study / Koert Nicolaas van der Walt." Thesis, 2014. http://hdl.handle.net/10394/12207.
Повний текст джерелаMSc (Sport Science), North-West University, Potchefstroom Campus, 2014
Brouillette-Alarie, Sébastien. "L’évaluation du risque de récidive des agresseurs sexuels : vers une approche centrée sur les construits psychologiques." Thèse, 2016. http://hdl.handle.net/1866/18446.
Повний текст джерелаLes outils actuariels servant à évaluer le risque de récidive criminelle des agresseurs sexuels ont souvent été critiqués pour leurs fondements « athéoriques ». En effet, ces derniers ont été constitués en rassemblant les caractéristiques les plus fortement associées à la récidive, sans qu’une théorie ne les unisse à priori. Si cette méthode a assuré une bonne validité prédictive à ces instruments, elle leur a insufflé très peu de résonnance clinique; plusieurs professionnels n’y voient qu’une liste de corrélats statistiques vides de sens. La présente thèse a entrepris de relativiser ces critiques en appliquant des modèles de facteurs latents aux différents items des outils actuariels. Les modèles de facteurs latents postulent que les comportements manifestes (observables) d’un individu renseignent sur ses caractéristiques psychologiques latentes (non observables) – de la même manière que les symptômes d’une maladie permettent d’inférer sa présence chez un patient. Puisque les items des outils actuariels correspondent à divers comportements ou caractéristiques criminogènes manifestes, il devrait être possible de les rassembler en dimensions pour identifier les principaux construits psychologiques latents associés à la récidive des agresseurs sexuels. Les articles de la présente thèse ont donc proposé d’identifier les dimensions de la Statique-99R et de la Statique-2002R, la famille d’outils actuariels pour agresseurs sexuels la plus utilisée mondialement. Trois dimensions ont été extraites par analyse factorielle : 1) la persistance dans les délits sexuels/paraphilies sexuelles, 2) la délinquance générale et 3) le jeune âge/victimes sexuelles non familières. La première dimension était exclusivement associée à la récidive sexuelle, tandis que les deux dernières étaient associées à tous les types de récidives. Leur validité convergente a ensuite été explorée afin d’évaluer à quelles caractéristiques psychologiques ces dernières référaient. La persistance/paraphilie a convergé avec des indicateurs d’intérêts sexuels déviants non coercitifs, alors que la délinquance générale a convergé avec une constellation de traits antisociaux. Finalement, le jeune âge/victimes sexuelles non familières a convergé avec l’intention claire de blesser ses victimes. Ces résultats ont mené au développement d’un modèle tridimensionnel du risque de récidive des agresseurs sexuels ayant plusieurs implications pratiques pour le domaine. D’une part, les outils actuariels gagneraient à utiliser des scores dimensionnels plutôt que des scores totaux. Par exemple, en retirant la dimension de persistance/paraphilie de la Statique-99R/2002R, il est possible de prédire efficacement la récidive violente non sexuelle et non sexuelle non violente des agresseurs sexuels, ce que l’instrument ne permettait pas précédemment. D’autre part, la connaissance des grandes dimensions de facteurs de risque est susceptible d’aider les évaluateurs à choisir et intégrer plusieurs mesures actuarielles. Cela se révèle particulièrement pertinent lorsque deux mesures du risque divergent, malgré qu’elles aient été conçues pour la même population. Finalement, nos résultats indiquent que les facteurs de risque statiques sont susceptibles de renseigner (imparfaitement) la pratique clinique quant aux besoins criminogènes des agresseurs sexuels. Bien que nous ne suggérions aucunement de substituer cette pratique à la cotation d’outils actuariels de troisième génération, elle pourrait se révéler pertinente pour les établissements n’ayant pas les ressources nécessaires pour coter de tels instruments. Au plan théorique, le modèle tridimensionnel comporte plusieurs avantages par rapport aux modèles à deux dimensions, traditionnellement constitués de la déviance sexuelle et de la délinquance générale/psychopathie (ex. : Doren, 2004). D’une part, les données empiriques supportent clairement la présence de trois dimensions du risque de récidive des agresseurs sexuels, et non deux. D’autre part, la troisième dimension permet d’intégrer une nuance importante au modèle, soit la distinction entre les intérêts sexuels déviants par leur objet de désir (ex. : pédophilie) et les intérêts sexuels déviants par leur aspect coercitif (ex. : sadisme sexuel). Cette distinction est primordiale, dans la mesure où ces intérêts sexuels ne prédisent pas les mêmes types de récidives. Finalement, notre modèle s’intègre au modèle étiologique du risque de Beech et Ward (2004), qui, lorsque complètement validé, pourra donner lieu à des efforts de prévention – une denrée rare dans le domaine.
Actuarial scales for the prediction of sexual violence have been criticised because they are purely based on atheoretical correlates. Therefore, they are unlikely to provide clinical and theoretical insight on the psychological traits and mechanisms that underlie criminal recidivism. However, according to latent variable models commonly used in psychology, patterns of behavior, thought, and emotion are caused by latent psychological constructs, such as extraversion and neuroticism. Because static and stable risk factors in actuarial scales are mostly behavioral, it should be possible to use them to infer the major psychological constructs responsible for recidivism risk. The current thesis applied latent variable models to nonredundant items from the Static-99R and Static-2002R, the two most commonly used risk tools for sexual offenders. Three dimensions were identified: 1) persistence in sexual crimes/paraphilia, 2) general criminality, and 3) youthful stranger aggression. To understand the psychological meaning of these dimensions, convergent and predictive validity analyses were conducted. Results indicated that persistence/paraphilia was related to dysregulation of sexuality towards atypical objects, without intent to harm, while general criminality was related to antisocial traits. Finally, youthful stranger aggression was related to a clear intent to harm victims. All three constructs predicted sexual recidivism with similar accuracy, but only general criminality and youthful stranger aggression predicted nonsexual recidivism. These results suggest that a tridimensional model of sexual offender risk is viable. That model has numerous practical implications. First, actuarial scales should sort items by constructs rather than rely on total scores. Total scores focus the predictive utility of risk scales to the specific outcome for which they were developed (usually sexual recidivism). When constructs are known, it is possible to improve the prediction of other outcomes by removing constructs unrelated to each of these new outcomes (e.g., removing sexual criminality items to improve the prediction of nonsexual recidivism). Second, construct-level approaches facilitate the integration of potentially conflicting risk scales. By understanding the constructs assessed by each scale, an evaluator can deduce which measures should be combined, and which should not. Finally, static risk constructs significantly correlate with psychological features that are found in dynamic risk scales. Consequently, scales composed entirely of static risk factors could – albeit imperfectly – inform the treatment needs of sexual offenders. These results could assist settings lacking the resources to implement dynamic risk tools. The tridimensional model also has theoretical implications. First, our model showed better statistical fit than classical two factor models based on sexual deviance and psychopathy (e.g., Doren, 2004), suggesting that there are more than two substantive dimensions related to sexual offender recidivism risk. Second, the presence of a third factor enabled an important distinction between noncoercive (e.g., fixated pedophilia) and coercive (e.g., sexual sadism) deviant sexual interests. Such a distinction is particularly relevant in the field of risk assessment, because they do not predict the same types of recidivism. Finally, our model can be integrated in Beech and Ward’s (2004) etiological model of risk, which, once fully validated, could enable primary and secondary prevention efforts.