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Owsley, Lane M. D. "Classification of transient events in time series /". Thesis, Connect to this title online; UW restricted, 1998. http://hdl.handle.net/1773/5989.
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Santos, Rui Pedro Silvestre dos. "Time series morphological analysis applied to biomedical signals events detection". Master's thesis, Faculdade de Ciências e Tecnologia, 2011. http://hdl.handle.net/10362/10227.
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Dissertation submitted in the fufillment of the requirements for the Degree of Master in Biomedical EngineeringAutomated techniques for biosignal data acquisition and analysis have become increasingly powerful, particularly at the Biomedical Engineering research field. Nevertheless, it is verified the need to improve tools for signal pattern recognition and classification systems, in which the detection of specific events and the automatic signal segmentation are preliminary processing steps. The present dissertation introduces a signal-independent algorithm, which detects significant events in a biosignal. From a time series morphological analysis, the algorithm computes the instants when the most significant standard deviation discontinuities occur, segmenting the signal. An iterative optimization step is then applied. This assures that a minimal error is achieved when modeling these segments with polynomial regressions. The adjustment of a scale factor gives different detail levels of events detection. An accurate and objective algorithm performance evaluation procedure was designed. When applied on a set of synthetic signals, with known and quantitatively predefined events, an overall mean error of 20 samples between the detected and the actual events showed the high accuracy of the proposed algorithm. Its ability to perform the detection of signal activation onsets and transient waveshapes was also assessed, resulting in higher reliability than signal-specific standard methods. Some case studies, with signal processing requirements for which the developed algorithm can be suitably applied, were approached. The algorithm implementation in real-time, as part of an application developed during this research work, is also reported. The proposed algorithm detects significant signal events with accuracy and significant noise immunity. Its versatile design allows the application in different signals without previous knowledge on their statistical properties or specific preprocessing steps. It also brings added objectivity when compared with the exhaustive and time-consuming examiner analysis. The tool introduced in this dissertation represents a relevant contribution in events detection, a particularly important issue within the wide digital biosignal processing research field.
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Deshpande, Kshitija Bharat. "A Dedicated Search for Low Frequency Radio Transient Astrophysical Events using ETA". Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/35666.
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Astrophysical phenomena such as self-annihilation of primordial black holes (PBHs), gamma ray bursts (GRBs), and supernovae are expected to produce single dispersed pulses detectable in the low end of the radio spectrum. Analysis of these pulses could provide valuable information about the sources, and the surrounding and intervening medium. The Eight-meter-wavelength Transient Array (ETA) is a radio telescope dedicated to the search for these pulses in an 18 MHz bandwidth centered at 38 MHz. ETA consists of 10 dual-polarized active dipoles providing an all-sky field of view. This thesis describes the results of a search campaign using ETA, namely, a Crab giant pulse (CGP) search. CGPs are already known to exist, and thus provide an excellent diagnostic for system performance. We found 11 CGP candidates in 14 hours of data. Although there has not been a single compelling detection (signal-to-noise ratio > 6), our analysis shows that at least a few of these candidates may be CGPs. We also explain the analysis preparation for PBH and GRB searches. Additionally, we describe the instrument and a software "toolchain" developed for the analysis of data that includes calibration, radio frequency interference (RFI) mitigation, and incoherent dedispersion. A dispersed pulse simulation code was developed and used to test the toolchain. Finally, improvements are suggested.Master of Science
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Allgood, Michael David Baginski Michael E. "Finite element analysis of the mesosphere's electromagnetic response to large scale lightning associated with sprites and other transient luminous events". Auburn, Ala, 2008. http://repo.lib.auburn.edu/EtdRoot/2008/SPRING/Electrical_and_Computer_Engineering/Thesis/Allgood_Michael_37.pdf.
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Hoeker, Gregory Scott. "MECHANISMS OF CALCIUM-MEDIATED ARRHYTHMOGENESIS IN HEART FAILURE". Case Western Reserve University School of Graduate Studies / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=case1195243457.
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Hidalga, García-Bermejo Patricio. "Development and validation of a multi-scale and multi-physics methodology for the safety analysis of fast transients in Light Water Reactors". Doctoral thesis, Universitat Politècnica de València, 2021. http://hdl.handle.net/10251/160135.
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[ES] La tecnología nuclear para el uso civil genera más preocupación por la seguridad que muchas otras tecnologías que se usan a diario. La Autoridad Nuclear define las bases de cómo debe realizarse la operación segura de una Central Nuclear. De acuerdo a las directrices establecidas por la Autoridad Nuclear, una Central Nuclear debe analizar una envolvente de escenarios hipotéticos y comprobar de manera determinista que los criterios de aceptación para dicho evento se cumplen. El Análisis Determinista de Seguridad utiliza herramientas de simulación que aplican la física conocida sobre el comportamiento de la Central Nuclear para evaluar la evolución de una variable de seguridad y asegurar que los límites no se sobrepasan.
El desarrollo de la tecnología informática, de los métodos matemáticos y de la física que envuelve el comportamiento de una Central Nuclear han proporcionado herra-mientas de simulación potentes que son capaces de predecir el comportamiento de las variables de seguridad con una importante precisión. Esto permite analizar escenarios de manera más realista evitando asumir condiciones conservadoras que hasta la fecha compensaban la falta de conocimiento modelado en las herramientas de simulación. Las herramientas conocidas como De Mejor Estimación son capaces de analizar even-tos transitorios en diferentes escalas. Además, emplean modelos analíticos de las dife-rentes físicas más detallados, así como correlaciones experimentales más realistas y actuales. Un paso adelante en el Análisis Determinista de Seguridad pretende combinar las diferentes herramientas de Mejor Estimación que se emplean para analizar las dis-tintas físicas de una Central Nuclear, considerando incluso la interacción entre ellas y el análisis progresivo a diferentes escalas, llegando a analizar fenómenos más locales si es necesario.
Para este fin, esta tesis presenta una metodología de análisis multi-físico y multi-escala que emplea diferentes códigos de simulación analizando el escenario propuesto a dife-rentes escalas, es decir, desde un nivel de planta que incluye los distintos componentes, hasta el volumen de control que supone el refrigerante pasando entre las varillas de combustible. Esta metodología permite un flujo de información que va desde el análi-sis a mayor escala hasta el de menor escala. El desarrollo de esta metodología ha sido validado con datos de planta para poder evaluar el alcance de esta metodología y pro-porcionar nuevas líneas de trabajo futuro. Además, se han añadido los resultados de los distintos procesos de validación y verificación que han surgido a lo largo de este trabajo.[CA] La tecnologia nuclear per a l'ús civil genera més preocupació per la seguretat que moltes altres tecnologies d'ús quotidià. L'Autoritat Nuclear defineix les bases de com ha de realitzar-se l'operació segura d'una Central Nuclear. D'acord amb les directrius establertes per l'Autoritat Nuclear, una Central Nuclear ha d'analitzar una envoltant d'escenaris hipotètics I comprovar de manera determinista que els criteris d'acceptació per a l'esdeveniment seleccionat es compleixen. L'Anàlisi Determinista de Seguretat utilitza eines de simulació que apliquen la física coneguda sobre el comportament de la Central Nuclear per avaluar l'evolució d'una variable de seguretat i assegurar que els límits no es traspassen. El desenvolupament de la tecnologia informàtica, els mètodes matemàtics i de la física que envolta el comportament d'una Central Nuclear han proporcionat eines de simulació potents amb capacitat de predir el comportament de les variables de seguretat amb una precisió significativa. Això permet analitzar escenaris de manera realista evitant assumir condicions conservadores que fins al moment compensaven la mancança de coneixement. Les eines de simulació conegudes com De Millor Estimació son capaces d'analitzar esdeveniment transitoris a diferent escales. A més, utilitzen models analítics per a les diferents físiques amb més detall així com correlacions experimentals més actualitzades i realistes. Un pas més endavant en l'Anàlisi Determinista de Seguretat pretén combinar les diferents eines de Millor Estimació que se utilitzen per analitzar les distintes físiques d'una Central Nuclear, considerant inclús la interacció entre ells i l'anàlisi progressiu a diferents escales, amb la finalitat de poder analitzar fenòmens locals. Per a aquest fi, esta tesi presenta una metodologia d'anàlisi multi-física i multi-escala que utilitza diferents codis de simulació analitzant l'escenari proposat a diferents escales, és a dir, des d'un nivell de planta que inclou els distints components, fins al volum de control que suposa el refrigerant passant entre les varetes de combustible. Esta metodologia permet un flux de informació que va des de l'anàlisi d'una escala major a una menor. El desenvolupament d'aquesta metodologia ha sigut validada i verificada amb dades de planta i els resultats han sigut analitzats a fi d'avaluar la capacitat de la metodologia i les possibles línies de treball futur. A més s'han afegit els principals resultats de verificació i validació que han sorgit en les distintes etapes d'aquest treball.
[EN] The nuclear technology for civil use has generated more concerns for the safety than several other technologies applied to the daily life. The Nuclear Regulators define the basis of how the Safety Operation of Nuclear Power Plants is to be done. According to these guidelines, a Nuclear Power Plant must analyze an envelope of hypothetical events and deterministically define if the acceptance criteria for these events is met. The Deterministic Safety Analysis uses simulation tools that apply the physics known in the behavior of the Nuclear Power Plant to evaluate the evolution of a safety varia-ble and assure that the safety limits will not be exceeded. The development of the computer science, the numerical methods and the physics involved in the behavior of a Nuclear Power Plant have yield powerful simulation tools that are capable to predict the evolution of safety variables which significant accuracy. This allows to consider more realistic simulation scenarios instead of con-servative approaches in order to compensate the lack of knowledge in the applied prediction methods. The so called Best Estimate simulation tools are capable to analyze the transient events in different scales. Furthermore, they account more detailed analytical models and experimental correlations. A step forward in the Deterministic Safety Analysis intends to combine the Best Estimate simulation tools of the different physics considering the interaction among them and analyzing the different scales, considering more local approaches if necessary. For this purpose, this thesis work presents a multi-scale and multi-physics methodology that uses different physics codes and has the aim of modeling postulated scenarios in different scales, i.e. from system models representing the components of the plants to the subchannel models that analyze the behavior of the coolant between the fuel rods. This methodology allows a flow of information where the output of one scale is used as input in a more detailed scale to predict a more local analysis of parameters, such as the Critical Power Ratio, which are of great importance for the estimation of safety margins. The development of this methodology has been validated against plant data with the aim of evaluating the scope of this methodology and in order to provide future lines of development. In addition, different results of the validation and verifi-cation yielded in the development of the parts of this methodology are presented.
Hidalga García-Bermejo, P. (2020). Development and validation of a multi-scale and multi-physics methodology for the safety analysis of fast transients in Light Water Reactors [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/160135
TESIS
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Westlund, Kenneth P. (Kenneth Peter). "Recording and processing data from transient events". Thesis, Massachusetts Institute of Technology, 1988. https://hdl.handle.net/1721.1/129961.
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Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1988.Includes bibliographical references.
by Kenneth P. Westlund Jr.
Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1988.
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Boyd, Alistair Richard. "Fluid-structure interaction under fast transient dynamic events". Thesis, University of Edinburgh, 1999. http://hdl.handle.net/1842/10835.
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Underwater explosive loading resulting from rapid phase transitions (RPT's) is one example of a fast transient dynamic event. The leakage of substances such as LPG or LNG when stored underwater can cause an RPT. These substances are often stored in a combination of very low temperatures and high pressures with respect to the surrounding fluid (seawater) and their leakage can cause the equivalent of an underwater explosion. Such containers are usually found to be part of a much larger 'storage field' of containers. An RPT occurring in one container will cause underwater explosive loading on neighbouring containers. By simulating an RPT using explosive charges experiments were initially designed using theoretical and empirical techniques. The fluid and structural response of a prototype container subject to symmetric and axisymmetric underwater explosive (UNDEX) loading was then examined experimentally. Theoretical predictions using the finite element hydrocode LS-DYNA and boundary element code USA-DYNA3D were undertaken and compared with experimental observations. Several non-destructive techniques were employed to estimate dynamic collapse buckling criteria from both experimental and theoretical results. The experimental work concluded that the critical regions of the prototype container were the apex and the base under both forms of loading. The quality of the numerical predictions varied dependent on the form of the loading. In some cases the fluid and structural responses were overpredicted, and in others underpredicted. Within the limitations of these numerical procedures it was possible to predict a conservative estimate of a critical charge size under axisymmetric UNDEX loading using LS-DYNA. The critical stand off distance was also estimated from experimental results under symmetric UNDEX loading. The use of numerical approaches to predict fluid-structure interaction as successful for the shock phase of an underwater loading and both LS-DYNA and USA-DYnA3D have been validated for shock loading. Bubble loading simulations proved unsuccessful. Suggested improvements are proposed to increase the application of, and enhance the reliability of, the techniques used in this work.
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Dusek, Daniel P. "Ocean mixed layer biological response to transient ocean events". Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1997. http://handle.dtic.mil/100.2/ADA340990.
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Thesis (M.S. in Physical Oceanography) Naval Postgraduate School, September 1997."September 1997." Thesis advisor(s): Roland W. Garwood. Includes bibliographical references (p. 61-63). Also available online.
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Price, Daniel James. "Forward modelling of transient events in the solar atmosphere". Thesis, Aberystwyth University, 2017. http://hdl.handle.net/2160/50cf4525-e93c-4c15-9c63-c5ed7daba471.
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The solar atmosphere is a highly magnetised plasma covering a wide range of temperatures from the thousands of Kelvin to the millions. How exactly it reaches such extreme temperatures remains unknown. There are however numerous events that take place, concerned with the movement of energy and plasma throughout the solar atmosphere. This thesis makes use of four instruments that have studied the Sun in the past, and in three cases continue to do so today. Observations from these instruments are combined with synthetic observations obtained from a detailed non-equilibrium ionisation hydrodynamic radiation code to understand the nature of what was observed and deduce physical information. One study presents the replication of light curves of a loop obtained by the Atmospheric Imaging Assembly (AIA). It finds that it was a cold loop heated by a pulse of energy at its footpoint consistent with the energy of a nano are. Another study replicates line proles of a structure observed by the Extreme-Ultraviolet Imaging Spectrometer (EIS) within an outflow region. We find that it is best modelled by a long loop consisting of at least 100 strands undergoing a cyclical process of heating and cooling on timescales of approximately 80 minutes. A final study replicates line profiles from the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) instrument, and uses images from the Transition Region and Coronal Explorer (TRACE) to add context to the interpretation.
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Clark, Kenneth A. "Modeling single-event transients in complex digital systems". Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02Jun%5FClark%5FKenneth%5Fphd.pdf.
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Khan, Umair A. (Umair Azim). "A multiprocessing platform for transient event detection". Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/36662.
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Abler, Craig Bennett 1975. "Spectral envelope estimation for transient event detection". Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/47690.
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Thesis (S.B. and M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1998.Includes bibliographical references (p. 133-134).
A Nonintursive Load Monitor (NILM) is a device that determines the operating schedule of electric loads by properly locating and identifying transient events in the spectral envelopes of the current waveform measured at the utility service entry. The spectral envelopes of the current waveform are the coefficients of its time varying Fourier series representation and as such can be estimated by low-pass filtering the current mixed with appropriate basis sinusoids. Spectral envelope estimators have been termed pre-processors. In this thesis, two pre-processors were designed. The first utilizes magic sine waves as the basis functions instead of sinusoids. The second is a digital pre-processor developed on a digital signal processor. The digital design was used in complete NILM platforms and its performance is analyzed to determine the quality of the envelopes produced. Finally, avenues for further work on the digital pre-processing unit are suggested.
by Craig Bennett Abler.
S.B.and M.Eng.
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Gardiner, Kelvin Thomas. "Mitigating Single Event Transients in Dual Rail Muller Pipelines". Thesis, University of Newcastle Upon Tyne, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.506555.
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Gangadhar, Sreenivas. "ANALYTICAL METHODS TO PROPAGATE AND DIAGNOSE SINGLE EVENT TRANSIENTS". OpenSIUC, 2012. https://opensiuc.lib.siu.edu/dissertations/538.
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Rapidly shrinking technology node and aggressive scaling of voltage have increased the probability of soft errors. In the current deep sub-micron technology, a small inaccuracy in computing the probability of occurrence of a soft error results in an unacceptably large chip failure rate. We propose a method that considers timing information to determine accurately the probability of SET propagation resulting into an error. Disjoint covers of appropriately formulated functions are used for the probability computations in order to consider re-convergent paths in the circuit. The probabilities are calculated at the output gate at different time instants that SET can propagate within a latching window considering electrical attenuation. Bayes' theorem is used to model the SET injection. The method is extended to consider multiple SETs. A novel method is proposed to enhance SET propagation probability and is shown how it can assist the hardening process. A method to determine a set of patterns is also proposed that must be applied at the inputs to determine propagation characteristics of the SET that are meaningful for hardening purposes. A heuristic based on the probabilistic framework for SET propagation is proposed to diagnose (on-line or off-line) the location and time of strike based on errors observed at multiple points. The proposed diagnostic framework requires a new approach to calculate the probability for SET propagation to multiple non-independent variables. It is shown experimentally that the error appearances at multiple observable points help in SET diagnosis. The time performance of the proposed diagnostic framework is compared against an alternative implementation. This is particularly important in on-line diagnosis. The proposed methods are experimentally verified on ISCAS and ITC benchmarks considering both fixed gate delays and probability distribution function gate delays .
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Bailey, Matthew A. "Investigating Characteristics of Lightning-Induced Transient Luminous Events Over South America". DigitalCommons@USU, 2010. http://digitalcommons.usu.edu/etd/667.
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Sprites, halos, and elves are members of a family of short-lived, luminous phenomena known as Transient Luminous Events (TLEs), which occur in the middle atmosphere. Sprites are vertical glows occurring at altitudes typically ranging from ~40 to 90 km. In video imagery they exhibit a red color at their top, with blue tendril-like structure at low altitudes. Elves are disk-like glows that occur at the base of the ionosphere, with diameters of ~100-300 km, and have very short lifetimes (~2-3 ms). Halos are diffuse glows that occur at low altitudes, have diameters <100 km, and have a duration that may last up to 10s of ms.
A majority of the studies of TLEs have taken place over the Midwestern U.S. where they were first discovered. This area produces large thunderstorms, which in turn generate large lightning discharges that have been associated with the formation of TLEs. Studies have used the low frequency radiation that initiates with these strokes to study characteristics of these events. This low frequency radiation has been used to determine where large numbers of TLEs may occur. Extreme southern Brazil is a region of the globe believed to have many TLEs, but few studies on these phenomena.
Two collaborative campaigns involving Utah State University proceeded in 2002-2003, and in 2006. Multiple TLE images were made, proving this is, indeed, a region of the globe where these types of events are prominent. In particular, one storm in February 2003 produced over 440 TLEs imaged by USU video cameras. Of these events, over 100 of them had associated halos. Statistical studies for halos previously had been performed in the U.S., but never abroad. Also, several events from the February storm have been associated with negative cloud to ground lightning, a surprising occurrence, as to date, less than a handful of such events have ever been witnessed or published.
In analyzing the TLEs from this campaign, we have shown the halos are similar to those seen in the U.S., even though the storms may be somewhat different. Also, detailed analyses of the negative events show both temporal and spatial morphology heretofore never reported on.
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Kóta, J., e J. R. Jokipii. "Transient Cosmic-ray Events beyond the Heliopause: Interpreting Voyager-1 Observations". IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/624725.
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In 2013 March and 2014 May, Voyager-1 (V1) experienced small but significant increases in the flux of galactic cosmic rays (GCRs) in the hundred MeV/n range. Additionally, V1 also saw episodic depletion of GCR flux around perpendicular pitch angles. We discuss the pitch-angle distribution and the time profiles of these events. In a previous paper, we interpreted the 2013 "bump" as the GCRs remotely sensing a shock that reached the magnetic field line passing through V1: particles gained energy as they were reflected on the approaching region of the stronger magnetic field of the disturbance. Here, we point out that energy gain is not restricted to reflected particles -GCRs passing through the disturbance also gain energy. The effect should be present in a broad range of pitch angles with the maximum increase of GCR intensity predicted to occur at the critical reflection angle. In this paper, the shock is not step-like, but a gradual increase of the magnetic field strength, B, taking a few days, in agreement with V1 measurements. This smoothens the profile of the predicted bump in the GCR flux. We also address the linear episodic decreases seen around perpendicular pitch angles. These events are interpreted in terms of adiabatic cooling behind the shock due to the slow weakening of B. We present simple numerical model calculations and find that a gradual shock followed by a slow decrease of B, as observed, may account for both the episodic increases and the anisotropic depletion of GCR fluxes.
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Marshall, Robert Andrew. "Very low frequency radio signatures of transient luminous events above thunderstorms /". May be available electronically:, 2009. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Quispe, Raul Dario Chipana. "Single event transient effects in clock distribution networks". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/114809.
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A redução na escala dos semicondutores tem aumentado a suceptibilidade de componentes eletrônicos a radiação. Single event transient (SET) afeta cada vez mais os circuitos integrados. Os efeitos da radiação podem afetar as redes de relógio dos circuitos integrados. Durante o impacto de uma partícula ionizada, a carga pode ser coletada na saída do buffer da rede de relógio e provocar um clock glich, clock jitter e clock skew. Como consequência do impacto, é possivel notar erros no fluxo do controle e no fluxo de dados do sistema. A presente tese investiga a suscetibilidade ao SET nas redes de relógio dos circuitos. Nós estamos interessados nos caminhos mais sensíveis da rede e nos registros que apresentam mais probabilidade de mudar de estado (bit-flip). Alguns bit-flips tem mais probabilidade de provocar uma falha na saída do circuito, enquanto outros podem ser mascarados pela aplicação. Nesta tese propomos uma nova metodologia para identificar os nós mais sensíveis e calcular o soft error rate causado pelo SET nas redes de relógio. Nossa metodologia utiliza uma ferramenta desemvolvida para esta tese chamada EXT-CLK, a ferramenta extrai a rede de relógio dos archivos de desenho do circuito para realizar diferentes simulações de injeção de SET. Como estudo de caso foi selecionado o circuito SRAM arbiter. Centenas de simulações foram feitas com o intuito de identificar os nós mais sensíveis da rede de relógio. Os resultados mostram 17 registros do ciruito SRAM arbiter terem alto índice de suscetibilidade. A informação encontrada nos resultados poderão ajudar os desenhadores a escolher a técnica de mitigação mais apropriada para o circuito antes de ser fabricado.Technology scaling to semiconductor has increased the radiation-induced susceptibility of electronic devices. Single Event Transient (SET) are becoming increasingly problematic for integrated circuits (ICs). Radiation effects may occur in the clock distribution networks of the ICs. During the strike of an ionizing particle, charge may be collected on the output node of the clock buffer, provoking a clock glitch, clock jitter and clock skew. As consequence of the impact, it is possible to notice errors in the control flow or data flow of the system. This work investigates the SET susceptibility in the clock distribution network of the circuit. We are interested in the most sensitive paths of the network and registers that are most likely to flip in the clock network. Some bit-flips are most likely to provoke a fault in the IC output once a failure occur in those elements. In the present work we propose a new methodology to identify the most sensitive nodes and to calculate the soft error rate due to SET in clock distribution network. This new methodology uses a tool developed in this thesis named EXT-CLK. The tool extracts the clock network from layout design files, to perform different simulations of SET injection in electrical and logic level. The SRAM arbiter circuit has been chosen as a case study. Thousands of electrical simulations have been performed in order to identify the sensitive nodes of the clock network. Results show that 17 registers of SRAM arbiter exhibit high vulnerability factor. This information can help the designers to use some mitigation techniques on those registers before the manufacturing process.
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Crowell, Brendan W. "Using GPS to Rapidly Detect and Model Earthquakes and Transient Deformation Events". Thesis, University of California, San Diego, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3558086.
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The rapid modeling and detection of earthquakes and transient deformation is a problem of extreme societal importance for earthquake early warning and rapid hazard response. To date, GPS data is not used in earthquake early warning or rapid source modeling even in Japan or California where the most extensive geophysical networks exist. This dissertation focuses on creating algorithms for automated modeling of earthquakes and transient slip events using GPS data in the western United States and Japan. First, I focus on the creation and use of high-rate GPS and combined seismogeodetic data for applications in earthquake early warning and rapid slip inversions. Leveraging data from earthquakes in Japan and southern California, I demonstrate that an accurate magnitude estimate can be made within seconds using P wave displacement scaling, and that a heterogeneous static slip model can be generated within 2-3 minutes. The preliminary source characterization is sufficiently robust to independently confirm the extent of fault slip used for rapid assessment of strong ground motions and improved tsunami warning in subduction zone environments. Secondly, I investigate the automated detection of transient slow slip events in Cascadia using daily positional estimates from GPS. Proper geodetic characterization of transient deformation is necessary for studies of regional interseismic, coseismic and postseismic tectonics, and miscalculations can affect our understanding of the regional stress field. I utilize the relative strength index (RSI) from financial forecasting to create a complete record of slow slip from continuous GPS stations in the Cascadia subduction zone between 1996 and 2012. I create a complete history of slow slip across the Cascadia subduction zone, fully characterizing the timing, progression, and magnitude of events. Finally, using a combination of continuous and campaign GPS measurements, I characterize the amount of extension, shear and subsidence in the Salton Trough, one of the most complex zone of active faulting and seismicity in California. I show the implications that faulting in the Salton Trough has for the evolution of the Brawley Seismic Zone, and more importantly, the southern San Andreas fault.
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Cuellar, Sandra Milena Conde. "3D model magneto-acoustic waves in coronal loops observed during transient events". Instituto Nacional de Pesquisas Espaciais (INPE), 2017. http://urlib.net/sid.inpe.br/mtc-m21b/2017/05.05.02.33.
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We present a three-dimensional analysis of magneto-acoustic waves, along the seven coronal loops, observed on the active region NOAA 11272 during the class B and C flares. We found 19-, 9-, 5-, 2-, 1-, and 0.6-minute waves using the pixelised wavelet filtering method over images obtained from the Atmospheric Imaging Assembly instrument. We modelled the velocity of these waves along the extrapolated magnetic field lines that reproduce the observed loops in extreme ultraviolet. The extrapolation was made over magnetograms, got from the Helioseismic and Magnetic Imager instrument, using the linear force-free approximation. From our model, we found temperatures 10$^{3}$ (maior equivalente) T (menor equivalente) 1.8 x 10$^{7}$ K and densities 10$^{7}$ (maior equivalente) n (menor equivalente) 10$^{17}$ cm$^{−3}$, covering from photosphere to corona, as expected in the solar atmosphere. Hence, we obtained acoustic c$_{s}$ $\approx$ 10$^{2}$ km s$^{−1}$ and Alfvénic $\upsilon$$_{A}$ $\approx$ 10$^{4}$ km s$^{−1}$ velocities values which are in agreement with the literature. In addition, the brightness asymmetry observed along the coronal loops is explained by the magnetic field and Alfvén velocity distributions along the extrapolated field lines. We found fast magneto-acoustic waves at the beginning of B3.8 and C1.9 flares and slow modes along the loops during all flares. Our 3D model represents an unprecedented method to study waves in coronal loops. All results are coherent with expected values in the solar atmosphere conditions.Apresentamos uma análise tridimensional de ondas magnetoacústicas ao longo de sete loops coronais, observados na região ativa NOAA 11272 durante os flares de classe B e C. Encontramos ondas de 19, 9, 5, 2, 1 e 0.6 minutos usando o método Pixelised Wavelet Filtering sobre imagens obtidas com o instrumento Atmospheric Imaging Assembly. Modelamos as velocidades dessas ondas ao longo das linhas de campo magnético extrapoladas que reproduzem os loops observados em ultravioleta extremo. A extrapolação foi feita sobre os magnetogramas obtidos com o instrumento Helioseismic and Magnetic Imager, usando a aproximação Linear Force-Free. A partir do nosso modelo, encontramos temperaturas de 10$^{3}$ (maior equivalente) T (menor equivalente) 1.8 x 10$^{7}$ K e densidades de 10$^{7}$ (maior equivalente) n (menor equivalente) 10$^{17}$ cm$^{−3}$, cobrindo desde a fotosfera até a coroa, como esperado na atmosfera solar. Desta forma, obtivemos valores para as velocidades acústica e Alfvénica de c$_{s}$ $\approx$ 10$^{2}$ km s$^{−1}$ e $\upsilon$$_{A}$ $\approx$ 10$^{4}$ km s$^{−1}$ respectivamente, as quais estão acorde com a literatura. Adicionalmente, a assimetria no brilho observada ao longo dos loops coronais é explicada pelas distribuições do campo magnético e da velocidade Alfvén ao longo das linhas extrapoladas. Nós encontramos ondas magnetoacústicas rápidas no inicio dos flares B3.8 e C1.9 e modos lentos ao longo dos loops durante todos os flares. O nosso modelo representa um método inédito para estudar ondas em loops coronais. Todos os resultados são coerentes com os valores esperados nas condições da atmosfera solar.
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Kintscher, Thomas. "Rapid Response to Extraordinary Events: Transient Neutrino Sources with the IceCube Experiment". Doctoral thesis, Humboldt-Universität zu Berlin, 2020. http://dx.doi.org/10.18452/21948.
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Im Jahr 2013 ist es dem IceCube-Experiment gelungen, einen Fluss von Neutrinos extraterrestrischen Ursprungs nachzuweisen, und damit das Neutrino als weiteres kosmisches Botenteilchen zu etablieren. Die Frage nach dem Ursprung der Neutrinos, die einen komplementären Blick auf die Quellen bieten, kann möglicherweise die alte Frage nach dem Ursprung der kosmischen Strahlung lösen.
Zeitunabhängige Suchen nach Neutrinoquellen konnten bisher keine einzelnen Kandidaten isolieren. Zeitlich veränderliche Quellen kommen daher als Ursprung in Betracht. IceCube ermöglicht es, kontinuierlich den gesamten Himmel nach aufflackernden Neutrinoquellen abzusuchen und die astronomische Gemeinschaft schnellstmöglich zu benachrichtigen.
In dieser Arbeit wird die Echtzeitidentifikation und -rekonstruktion von Myonneutrinokandidaten mit IceCube verbessert. Die erreichte Sensitivität ist mit etablierten nicht-Echtzeit Analysen vergleichbar. Kontinuierlich vom Experiment am Südpol übermittelte Informationen werden sofort auf bemerkenswerte Ereignisse hin analysiert. Bekannte astrophysikalische Quellen von Gammastrahlung werden auf Neutrinoemission hin beobachtet. Eine verallgemeinerte Methode erlaubt die Suche nach Signalen überall, unbeeinflusst von vorher bekannten Quellen. Weiterhin werden die hochenergetischsten Neutrinokandidaten, die wahrscheinlich astrophysikalischen Ursprungs sind, sofort identifiziert und global bekannt gemacht.
Abschließend werden die Suchalgorithmen am Beispiel zweier Blazare demonstiert,
1ES 1959+650 und TXS 0506+56. In letzterem Fall wurden erstmals Anzeichen für eine Quelle hochenergetischer, kosmischer Neutrinos gefunden.
Die im Rahmen dieser Arbeit entwickelte Infrastruktur erlaubt es, die astronomische Gemeinschaft auf signifikante Neutrinoereignisse, oder sich entwickelnde Neutrinocluster
hinzuweisen. Auch die zügige Suche nach Neutrinos in Reaktion auf interessante astrophysikalische Ereignisse, wie z.B. Gravitationswellen, ist möglich.The discovery of an flux of neutrinos of astrophysical origin with the IceCube experiment in 2013 has broadened our understanding of cosmic messengers and opened a new window on the universe. By addressing the newly pertinent question about their sources, neutrinos can provide a complementary view on cosmic accelerators and may help solving the long-standing puzzle of the origin of the cosmic rays. As traditional time-integrated searches for sources of neutrinos have not been able to isolate individual candidates, variable and transient sources shift into focus. IceCube's design allows to continuously search the entire sky for neutrino flares, and alert the community with the lowest possible latency in the case of a detection. This thesis improves the identification and reconstruction of muon neutrino candidates with IceCube in real-time, achieving a sensitivity comparable to dedicated offline analyses. The stream of neutrino candidates is analyzed for interesting events in order to alert partner experiments and inspire follow-up observations. First, known gamma-ray emitters are monitored for time-variable neutrino emission. Second, a generalization of this method monitors the entire sky for neutrino flares, regardless of pre-defined source lists. Third, the most-energetic neutrino candidates with the highest chance to be of astrophysical origin are selected for alerts. Eventually, the search methods are applied to the blazars 1ES 1959+650 and TXS 0506+056. In the latter case, evidence for source of high-energetic, astrophysical neutrinos was found for the first time. The infrastructure built in this work allows to notify the community whenever significant neutrino events are recorded, or significant flares develop on time-scales from days to weeks. It also allows to quickly perform neutrino follow-up searches in response to interesting astrophysical events, such as the observation of gravitational waves.
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Irewall, Anna-Lotta. "Recurrent events and secondary prevention after acute cerebrovascular disease". Doctoral thesis, Umeå universitet, Medicin, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-130505.
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Background Patients who experience a stroke or transient ischemic attack (TIA) are at high risk of recurrent stroke, but little is known about temporal trends in unselected populations. Reports of low adherence to recommended treatments indicate a need for enhanced secondary preventive follow-up to achieve the full potential of evidence-based treatments. In addition, socioeconomic factors have been associated with poor health outcomes in a variety of contexts. Therefore, it is important to assess the implementation and results of secondary prevention in different socioeconomic groups. Aims The aims of this thesis were to assess temporal trends in ischemic stroke recurrence and evaluate the implementation and results of a nurse-led, telephone-based follow-up program to improve blood pressure (BP) and low-density lipoprotein cholesterol (LDL-C) levels after stroke/TIA. Methods In study I, we collected baseline data for unique patients with an ischemic stroke event between 1998 and 2009 (n=196 765) from the Swedish Stroke Register (Riksstroke). Recurrent ischemic stroke events within 1 year were collected from the Swedish National Inpatient Register (IPR) and the cumulative incidence was compared between four time periods using the Kaplan-Meier survival analysis and the logrank test. Implementation (study II) and 1-year results (study III-IV) for the secondary preventive follow-up were studied in the NAILED (Nurse-based Age-independent Intervention to Limit Evolution of Disease) study. Between 1 Jan 2010 and 31 Dec 2013, the baseline characteristics of consecutive patients admitted to Östersund Hospital for acute stroke or TIA were collected prospectively (n=1776). Consenting patients in a condition permitting telephone-based follow-up were randomized to nurse-led, telephone-based follow-up or follow-up according to usual care. Follow-up was cunducted at 1 and 12 months after discharge and the intervention included BP and LDL-C measurements, titration of medication, and lifestyle counseling. In study II, we analyzed factors associated with non-participation in the randomized phase of the NAILED study, including association with education level. In addition, we compared the 1-year prognosis in terms of cumulative survival between participants and non-participants. In study III, we compared differences in BP and LDL-C levels between the intervention and control groups during the first year of follow-up and, in study IV, in relation to level of education (low, ≤10 years; high, >10 years). Results The cumulative 1-year incidence of recurrent ischemic stroke decreased from 15.0% to 12.0%. Among surviving stroke and TIA patients, 53.1% were included for randomization, 35.7% were excluded mainly due to physical or cognitive disability, and 11.2% declined participation in the randomized phase. A low level of education was independently associated with exclusion, as well as the patient’s decision to abstain from randomization. Excluded patients had a more than 12-times higher risk of death within 1 year than patients who were randomized. After 1 year of follow-up, the mean systolic BP, diastolic BP, and LDL-C levels were 3.3 mmHg (95% CI 0.3 to 6.3), 2.3 mmHg (95% CI 0.5 to 4.2), and 0.3 mmol/L (95% CI 0.1 to 0.4) lower in the intervention group than among controls. Among participants with values above the treatment goal at baseline, the differences in systolic BP and LDL-C levels were more pronounced (8.0 mmHg, 95% CI 4.0 to 12.1; 0.6 mmol/L, 95% CI 0.4 to 0.9). In the intervention group, participants with a low level of education achieved similar or larger improvements in BP and LDL-C than participants with a high level of education. In the control group, BP remained unaltered and the LDL-C levels increased among participants with a low level of education. Conclusion The 1-year risk of ischemic stroke recurrence decreased in Sweden between 1998 and 2010. Nurse-led, telephone-based secondary preventive follow-up is feasible in just over half of the survivors of acute stroke and TIA and achieve better than usual care in terms of BP and LDL-C levels, and equality in BP improvements across groups defined by education level. However, a large proportion of stroke survivors are in a general condition precluding this form of follow-up, and their prognosis in terms of 1-year survival is poor. Patients with a low education level are over-represented within this group and among patients declining randomization for secondary preventive follow-up.
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Zhang, Rui. "Transformer modelling and influential parameters identification for geomagnetic disturbances events". Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/transformer-modelling-and-influential-parameters-identification-for-geomagnetic-disturbances-events(e7c8df5c-8fa9-491f-bc06-9cb90cbbf543).html.
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Power transformers are a key element in the transmission and distribution of electrical energy and as such need to be highly reliable and efficient. In power system networks, transformer core saturation can cause system voltage disturbances or transformer damage or accelerate insulation ageing. Low frequency switching transients such as ferroresonance and inrush currents, and increasingly what is now known as geomagnetic induce currents (GIC), are the most common phenomena to cause transformer core saturation. This thesis describes extensive simulation studies carried out on GIC and switching ferroresonant transient phenomena. Two types of transformer model were developed to study core saturation problems; one is the mathematical transformer magnetic circuit model, and the other the ATPDraw transformer model. Using the mathematical transformer magnetic circuit model, the influence of the transformer core structure on the magnetising current has been successfully identified and so have the transformers' responses to GIC events. By using the ATPDraw transformer model, the AC system network behaviours under the influence of the DC bias caused by GIC events have been successfully analysed using various simulation case studies. The effects of the winding connection, the core structure, and the network parameters including system impedances and transformer loading conditions on the magnetising currents of the transformers are summarised. Transient interaction among transformers and other system components during energisation and de-energisation operations are becoming increasingly important. One case study on switching ferroresonant transients was modelled using the available transformer test report data and the design data of the main components of the distribution network. The results were closely matched with field test results, which verified the simulation methodology. The simulation results helped establish the fundamental understanding of GIC and ferroresonance events in the power networks; among all the influential parameters identified, transformer core structure is the most important one. In summary, the five-limb core is easier to saturate than the three-limb transformer under the same GIC events; the smaller the side yoke area of the five-limb core, the easier it will be to saturate. More importantly, under GIC events a transformer core could become saturated irrespective of the loading condition of the transformer.
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West, Jeremy Michael. "The Expectation of Transition Events on Finite-state Markov Chains". BYU ScholarsArchive, 2009. https://scholarsarchive.byu.edu/etd/1731.
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Markov chains are a fundamental subject of study in mathematical probability and have found wide application in nearly every branch of science. Of particular interest are finite-state Markov chains; the representation of finite-state Markov chains by a transition matrix facilitates detailed analysis by linear algebraic methods. Previous methods of analyzing finite-state Markov chains have emphasized state events. In this thesis we develop the concept of a transition event and define two types of transition events: cumulative events and time-average events. Transition events generalize state events and provide a more flexible framework for analysis. We derive computable, closed-form expressions for the expectation of these two events, characterize the conditioning of transition events, provide an algorithm for computing the expectation of these events, and analyze the complexity and stability of the algorithm. As an application, we derive a construction of composite Markov chains, which we use to study competitive dynamics.
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Lundie, Casper H. "Cinematic space : events pavilion and digital media gallery at the union grounds Johannesburg". Diss., University of Pretoria, 2014. http://hdl.handle.net/2263/45298.
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The transition from Apartheid urban space to – something else – draws our attention from the fixing moments of historically divided cities to the experience of mobility, interaction and the dynamism of space.
(Robinson 1999: 163)
This dissertation will approach the modern, post-colonial and post-apartheid African city as experimental ground for exploring, understanding and expressing spatial dynamics through the visual language of cinema. The proposal intends to mediate between the complex historical context which is manifested in the built fabric of the city and the new dynamic and often unstable urban conditions of Johannesburg, by specifically focusing on the contrasting conditions of the Johannesburg Art Gallery and the Noord Street Taxi Rank.
The role of cinema as a philosophical device in this dissertation is to produce a point of inception, an assemblage, or a terrain of encounter through which the project will be further investigated and articulated. The principal aim of the dissertation is to effectively react to contrasting aspects of both heritage and transience, whilst simulating the Cinematic Gaze, by creating a public platform that serves as an aperture for viewing as well as an urban stage with the potential to be viewed.
The hypothesis states that, if successfully applied, cinematic space can accentuate the unique and vibrant conditions of the inner city. This will ultimately lead the city dweller to a better sense of association with his/her immediate surroundings and a better comprehension of his/her role in place-and-time in the urban environmentDissertation (MArch(Prof))--University of Pretoria, 2014.
Architecture
MArch(Prof)
Unrestricted
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Pai, Ajith V. "Air induction noise investigation during turbocharger surge events in petrol engines". Thesis, Loughborough University, 2015. https://dspace.lboro.ac.uk/2134/19449.
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Turbocharging is used as a means to downsize petrol engines, thereby, producing more power for a lower engine size, when compared with a naturally aspirated engine. Due to the presence of a throttle valve in the intake system in petrol engines, flow is restricted at the outlet pipe of the compressor during low load engine operation. For example, during transient tip out tip in maneuvers. Hence, there is a chance of the turbocharger operating in near surge or surge conditions and, thus, generating surge noise. This Thesis describes an experimental and simulation method to predict and measure the turbocharger surge noise. Initially, experimental transient tip-in and tip-out maneuver was performed on a non turbocharged car with a petrol engine. The measured noise level in the intake manifold, at a low frequency of up to 1200 Hz, was analysed and was shown not to represent surge noise. Next, a one dimensional simulation method was applied to simulate the noise of the engine and this demonstrated an increase in the acoustic pressure level in the intake manifold during the tip in and tip out maneuver. However, a surge noise pattern was not observed in the analysis of acoustic pressure signals in the intake system using Short Time Fourier Transform (STFT). The simulation procedure was also used to inform the design of an experimental rig to recreate the surge noise under laboratory conditions. An experimental turbocharger noise rig, designed and built for this purpose, is explained in the Thesis. Important component parts likely to be involved in the surge noise generation such as the intake system, compressor, throttle body, compressor recirculation valve and measurement and control systems were integrated into the test rig. Background noise contributions from the electric motor, AC mains, supercharger pulley, throttle body, inverter fan, throttle body gearing and structural vibration of the supporting structure were identified from the analysed frequency components of the signals from surface microphone measurements taken at the intake system. This helped to clearly identify the surge noise frequency components (3250 Hz) in the STFT analysis. The fundamental mechanism of noise generation was identified using an analysis of the experimental results and a frequency calculation for vortex shedding and the radial acoustic resonances. One of the main conclusions of the Thesis is that the compressor recirculation valve (CRV) open or close position, the CRV delay time and the throttle position are major contributing factors to the cause of the surge noise. Another major conclusion is that the radial acoustic resonance may be a mechanism of surge noise generation. Finally, a passive solution to reduce the surge noise is proposed. A pipe with cross ribs is designed as a passive solution using the radial acoustic resonance calculation and the corresponding nodal patterns. This solution demonstrated a measured intake system noise reduction of up to 10dB under compressor surge conditions.
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Kintscher, Thomas [Verfasser]. "Rapid Response to Extraordinary Events: Transient Neutrino Sources with the IceCube Experiment / Thomas Kintscher". Berlin : Humboldt-Universität zu Berlin, 2020. http://d-nb.info/1219065803/34.
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Silva, Michele Gusson Vieira da. "Análise automatizada dos efeitos do alargamento de pulso induzido em single event transients". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/171361.
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Aplicações em ambientes expostos a elevados níveis de radiação ionizante impõem uma série de desafios ao desenvolvimento de projetos de circuitos integrados na tecnologia Complementary Metal–Oxide–Semiconductor (CMOS), uma vez que circuitos CMOS estão sujeitos às falhas transientes oriundas de radiação externa. Num circuito do tipo CMOS, as áreas sensíveis aos efeitos da incidência de partículas ionizantes são as regiões dreno-substrato reversamente polarizadas, existentes nos transistores em regime de corte (VARGAS; NICOLAIDIS, 1994). Com o avanço tecnológico e consequente diminuição das dimensões dos dispositivos semicondutores, estes efeitos degradantes tornam-se uma preocupação constante devido às menores características físicas dos transistores (WANG et al., 2007). Os circuitos integrados apresentam, durante a sua vida útil, um processo de degradação das suas características iniciais. Assim, a esse processo de degradação também chamamos de envelhecimento (aging). É um processo lento e cumulativo provocado por todos os mecanismos que acabam por alterar os parâmetros físicos e eléctricos dos circuitos, diminuindo o seu tempo de vida útil (FU; LI; FORTES, 2008). Dentre os efeitos de variabilidade temporal, os que mais têm causado interesse da comunidade científica são o Randon Telegraph Noise (RTN) com sua origem na atividade de traps (armadilhas) de interface e Single Event Transients (SET) com sua origem na radiação ionizante ao qual o circuito é exposto. Em relação aos efeitos de degradação destaca-se o efeito Bias Temperature Instability (BTI) (VALDUGA, 2012), que da mesma forma que o RTS, tem sua origem vinculada aos efeitos das traps.Modelos padrão para simulação elétrica de circuitos não levam em consideração os efeitos causados por armadilhas de cargas tais como Bias Temperature Instability (BTI) e Random Telegraph Noise (RTN). Tais variabilidades em nível de dispositivo podem causar perda de confiabilidade, como por exemplo, o surgimento de Propagation-Induced Pulse Broadening (PIPB). Conforme o escalonamento (scaling) tecnológico, a velocidade das portas lógicas aumenta e os SETs podem ser propagados através de circuito combinacional e, inclusive, sofrer alargamento, caso a largura do pulso transiente supere um valor mínimo crítico que depende da tecnologia (DODD et al., 2004), caracterizando assim um PIPB. Com base nisso, técnicas de injeção de falhas usadas em circuitos complexos não se mostram eficientemente previsíveis, levando a uma subestimativa da sensibilidade de circuitos à propagação de SETs. Com a utilização de um simulador elétrico que agrega a análise de BTI, temos melhores estimativas dos efeitos de PIPB na degradação de um circuito, que pode provocar violações de temporização em sistemas síncronos. Dessa forma, pode-se então trabalhar em uma projeção do circuito de forma a torná-lo mais robusto em relação aos efeitos de envelhecimento e na proteção às falhas transientes. Com base no que foi anteriormente apresentado, este trabalho analisa o comportamento de circuitos através de simulações elétricas de radiação ionizante, permitindo avaliações da suscetibilidade e confiabilidade de circuitos integrados aos efeitos de falhas transientes. Para a realização destes experimentos, foram realizadas simulações elétricas considerando-se os efeitos de envelhecimento. Para uma cadeia lógica de 2000 inversores sequencialmente dispostos na tecnologia 32nm pode-se prever que o pulso transiente está sujeito a um alargamento de sete vezes sua largura inicial no momento da incidência, para transistores em suas dimensões mínimas. A partir da proposta apresentada, pode-se determinar a possibilidade de alargamento ou atenuação de um SET ao longo do circuito de maneira eficiente para que as devidas precauções possam ser tomadas.Applications in environments exposed to high levels of ionizing radiation impose a number of challenges for the development of integrated circuit designs in CMOS technology. CMOS circuits are vulnerable to transient faults from external radiation. In a CMOS circuit, areas sensitive to the effects of ionizing particle incidence are as reverse polarized drain-substrate regions in the transistors at cut-off (VARGAS; NICOLAIDIS, 1994). The technological advance and consequent downscaling of semiconductor devices, these degrading factors become a constant concern due to the higher vulnerability to transient faults (WANG et al., 2007). The integrated circuits have during their useful life a process of degradation of their initial characteristics. Thus, this process of degradation is also called aging. It is a slow and cumulative process caused by all the mechanisms that end up changing the physical and electrical parameters of the circuits, decreasing their useful timing life (FU; LI; FORTES, 2008). Among the temporal variability effects, the Randon Telegraph Noise (RTN) with its origin in the activity of traps (interface traps) and Single Event Transients (SET) with their origin in the ionizing radiation circuit is exposed. In terms of the effects of degradation, the Bias Temperature Instability (BTI) effect (VALDUGA, 2012) stands out, which, like the RTS, has its origin linked to the effects of the traps. Standard electrical simulation models do not take into account the effects caused by charged traps such as Bias temperature instability (BTI) and random telegraph noise (RTN). Such device-level variability can cause reduced reliability, for example, the Propagation-Induced Pulse Broadening (PIPB). According to the technological scaling, the speed of the logic gates increases and the SETs can be propagated through a combinational circuit and even may suffer broadening if the transient pulse width exceeds a critical minimum value that depends on the technology (DODD et al., 2004 ), characterizing a PIPB. Based on this, fault injection techniques in complex circuits are not efficiently in predicting, leading to an underestimation of circuit sensitivity to propagation of Single Event Transients (SETs). Using an electrical simulator that aggregates a BTI analysis, we have better estimates of PIPB effects on circuit degradation, which may lead to timing violations in synchronous systems. Then we can put effort in circuit design in order to make it more robust regarding to aging effects and transient faults protection. Based on what has been previously presented, this thesis analyzes the behavior of circuits through electrical simulations of ionizing radiation, allowing susceptibility and reliability evaluations of integrated circuits to the effects of transient faults using electrical simulations. For the accomplishment of these experiments, electrical simulations were performance considering the effects of aging. For a logic chain of 2000 inverters sequentially arranged in the 32nm technology it can be predicted that the transient pulse is subjected to a broadening of seven times its initial width at the time of incidence for transistors with minimum dimensions. From the analysis presented, we can evaluate the possibility of broadening or shrinking of SETs thought the circuit in an efficient way to improve radiation-hardening techniques.
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Bèges, Rémi. "Analysis and modeling methods for predicting functional robustness of integrated circuits during fast transient events". Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30046/document.
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La miniaturisation des circuits intégrés se poursuit de nos jours avec le développement de technologies toujours plus fines et denses. Elle permet une intégration des circuits toujours plus massive, avec des performances plus élevées et une réduction des coûts de production. La réduction de taille des circuits s'accompagne aussi d'une augmentation de leur sensibilité électrique. L'électronique automobile est un acteur majeur dans la nouvelle tendance des véhicules autonomes. Ce type d'application a besoin d'analyser des données et d'appliquer des actions sur le véhicule en temps réel. L'objectif à terme est d'améliorer la sécurité des usagers. Il est donc vital de garantir que ces modules électroniques pourront effectuer leurs tâches correctement malgré toutes les perturbations auxquelles ils seront exposés. Néanmoins, l'environnement automobile est particulièrement sévère pour l'électronique. Parmi tous les stress rencontrés, les décharges électrostatiques (ESD - Electrostatic Discharge) sont une importante source d'agression électrique. Ce type d'évènement très bref est suffisamment violent pour détruire des composants électroniques ou les perturber pendant leur fonctionnement. Les recherches présentées ici se concentrent sur l'analyse des défaillances fonctionnelles. À cause des ESD, des fonctions électroniques peuvent cesser temporairement d'être opérantes. Des méthodes d'analyse et de prédiction sont requises au niveau-circuit intégré afin de détecter des points de faiblesses susceptibles de générer des fautes fonctionnelles pendant l'exposition à un stress électrostatique. Différentes approches ont été proposées dans ce but. Une méthode hiérarchique de modélisation a été mise au point afin d'être capable de reproduire la forme d'onde ESD jusqu'à l'entrée du circuit intégré. Avec cette approche, chaque élément du système est modélisé individuellement puis son modèle ajouté au schéma complet. Un cas d'étude réaliste de défaillance fonctionnelle d'un circuit intégré a été analysé à l'aide d'outils de simulation. Afin d'obtenir plus de données sur cette faute, une puce de test a été développée, contenant des structures de surveillance et de mesure directement intégrées dans la puce. La dernière partie de ce travail de recherche est concentrée sur le développement de méthodes d'analyse dans le but d'identifier efficacement des fautes par simulation. Une des techniques développées consiste à modéliser chaque bloc d'une fonction individuellement puis permet de chaîner ces modèles afin de déterminer la robustesse de la fonction complète. La deuxième méthode tente de construire un modèle équivalent dit boite-noire d'une fonction de haut-niveau d'un circuit intégré. Ces travaux de recherche ont mené à la mise au point de prototypes matériels et logiciels et à la mise en évidence de points bloquants qui pourront constituer une base pour de futurs travauxMiniaturization of electronic circuits continues nowadays with the more recent technology nodes being applied to diverse fields of application such as automotive. Very dense and small integrated circuits are interesting for economic reasons, because they are cheaper to manufacture in mass and can pack more functionalities with elevated performances. The counterpart of size reduction is integrated circuits becoming more fragile electrically. In the automotive world, the new trend of fully autonomous driving is seeing tremendous progress recently. Autonomous vehicles must take decisions and perform critical actions such as braking or steering the wheel. Those decisions are taken by electronic modules, that have now very high responsibilities with regards of our safety. It is important to ensure that those modules will operate no matter the kind of disturbances they can be exposed to. The automotive world is a quite harsh environment for electronic systems. A major source of electrical stress is called the Electrostatic Discharge (ESD). It is a very sudden flow of electricity of large amplitude capable of destroying electronic components, or disturb them during their normal operation. This research focuses on functional failures where functionality can be temporarily lost after an ESD with various impact on the vehicle. To guarantee before manufacturing that a module and its components will perform their duty correctly, new analysis and prediction methods are required against soft-failures caused by electrostatic discharges. In this research, different approaches have been explored and proposed towards that goal. First, a modelling method for reproducing the ESD waveforms from the test generator up to the integrated circuit input is presented. It is based on a hierarchical approach where each element of the system is modelled individually, then added to the complete setup model. A practical case of functional failure at silicon-level is analyzed using simulation tools. To acquire more data on this fault, a testchip has been designed. It contains on-chip monitoring structures to measure voltage and current, and monitor function behavior directly at silicon-level. The last part of this research details different analysis methods developed for identifying efficiently functional weaknesses. The methods rely heavily on simulation tools, and prototypes have been implemented to prove the initial concepts. The first method models each function inside the chip individually, using behavioral models, then enables to connect the models together to deduce the full function's robustness. It enables hierarchical analysis of complex integrated circuit designs, to identify potential weak spots inside the circuit that could require more shielding or protection. The second method is focused on constructing equivalent electrical black box models of integrated circuit functions. The goal is to model the IC with a behavioral, black-box model capable of reproducing waveforms in powered conditions during the ESD. In summary, this research work has led to the development of several hardware and software prototypes. It has also highlighted important modelling challenges to solve in future works to achieve better functional robustness against electrostatic discharges
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Alkan, Atilla Kaan. "Natural Language Processing for Analyzing Messages of Astrophysical Observations". Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASG114.
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Cette thèse aborde l’un des défis majeurs dans l’analyse de textes non structurés en astrophysique : l’extraction et la synthèse d’information sur des objets célestes à partir de rapports d’observation astronomique. L'extraction d'information (EI) est un sous-domaine clé du traitement automatique des langues (TAL), qui vise à transformer des textes non structurés en une représentation formelle et exploitable, permettant ainsi de structurer les connaissances contenues dans les documents. Les tâches classiques de l’EI incluent la reconnaissance d’entités nommées (REN), l'extraction de relations, ainsi que la résolution de coréférences. Toutefois, les modèles d'apprentissage statistique nécessaires pour ces tâches requièrent de vastes ensembles de données annotées manuellement, une condition qui devient difficile à satisfaire dans des domaines spécialisés tels que l'astrophysique. En effet, le manque de données annotées est un obstacle majeur dans ce domaine. Cette constatation, a motivé notre première question de recherche : quels concepts astrophysiques doivent être définis pour identifier les entités nommées pertinentes et quelles relations sémantiques doivent être mises en lumière entre ces entités ? Afin de répondre à cette question, nous avons travaillé en collaboration avec des astrophysiciens pour établir un guide d'annotation adapté, qui couvre non seulement les entités célestes, mais aussi les mentions de coréférence et les relations sémantiques entre ces entités. L'une des contributions majeures de cette thèse est la création d’astroECR, un corpus astrophysique composé de rapports d'observation, annoté de manière détaillée en entités nommées, coréférences et relations sémantiques. Bien que crucial, l’annotation manuelle s’avère particulièrement coûteux et fastidieux en termes de temps et de ressources humaines. Cette situation nous a conduit à poser notre deuxième question de recherche : Comment peut-on enrichir les données annotées manuellement afin d’entraîner efficacement des systèmes d’EI ? Pour ce faire, nous avons donc exploré l'efficacité des méthodes d'augmentation de données, un ensemble de techniques visant à générer des données artificielles pour améliorer les performances des modèles dans des contextes de données limitées. Nous avons formulé deux autres questions de recherche : Les techniques d'augmentation de données peuvent-elles compléter les annotations humaines et ainsi combler le manque de ressources spécialisées en astrophysique ? Quelles méthodes d’augmentation sont les plus adaptées pour des tâches comme la REN ou la résolution de coréférences ? Pour répondre à ces questions, nous avons proposé une série de méthodes d'augmentation de données à la fois simples et flexibles, adaptées aux tâches spécifiques de l'EI. Nous avons étudié deux grandes catégories de techniques d'augmentation : la première introduit de nouvelles mentions d'entraînement dans les données, tandis que la seconde modifie le contexte autour des mentions déjà existantes. Nous avons ensuite évalué ces méthodes en les appliquant à divers modèles de langue pré-entraînés et en les testant sur des rapports astronomiques annotés. Nos résultats montrent que de simples méthodes d'augmentation améliorent les performances en contexte de ressources limitées, offrant des perspectives pour l’EI et d’autres domaines à faible ressourceThis thesis addresses one of the major challenges in analysing unstructured texts in astrophysics: extracting and synthesising information about celestial objects from astronomical observation reports. Information extraction is a key subfield of Natural Language Processing (NLP) that aims to transform unstructured texts into a formal and usable representation, thereby structuring the knowledge contained in the documents. The classic information extraction tasks include named entity recognition (NER), relation extraction, and coreference resolution. However, the statistical learning models required for these tasks necessitate large manually annotated datasets, a condition difficult to meet in specialized domains such as astrophysics. Indeed, the scarcity of annotated data is a major obstacle to improving models in this domain. The advent of pre-trained and generative language models has led to significant advances in various areas of NLP. However, they are not specifically designed to handle astronomical observation reports or extract information about celestial objects. This lack of annotated data motivated our first research question: which astrophysical concepts should be defined to identify relevant named entities, and what semantic relationships should be highlighted between these entities? To address this question, we collaborated with astrophysicists to establish an adapted annotation guide covering celestial entities, coreference mentions, and semantic relations between these entities. One of the major contributions of this thesis is the creation of astroECR, an astrophysical corpus composed of observation reports annotated in detail with named entities, coreferences, and semantic relations. Although crucial, manual annotation is particularly costly and time-consuming in terms of time and human resources. This situation led us to pose our second research question: how can the amount of annotated data required to train information extraction systems be reduced effectively? We explored the effectiveness of data augmentation methods, a set of techniques aimed at generating artificial data to improve model performance in contexts of limited data. We formulated two additional research questions: Can data augmentation techniques enhance human annotations and thus compensate for the lack of specialized resources in astrophysics? Which augmentation methods are most suitable for tasks such as NER or coreference resolution? To answer these questions, we proposed a series of data augmentation methods that are both simple and flexible and adapted to the specific information extraction tasks. We studied two categories of augmentation techniques: the first introduces new training mentions into the data, while the second modifies the context around already existing mentions. We then evaluated these methods by applying them to various pre-trained language models and testing them on annotated astronomical reports. Our results show that even simple augmentation methods can improve model performance in resource-constrained contexts, offering promising prospects for information extraction in fields where annotated data are scarce. Furthermore, the proposed methods are potentially applicable to other low-resource disciplines
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Tucker, Simon. "An ecological approach to the classification of transient underwater acoustic events : perceptual experiments and auditory models". Thesis, University of Sheffield, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.401126.
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Müller, Andreas. "Coupling analysis of transient cardiovascular dynamics". Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät, 2016. http://dx.doi.org/10.18452/17452.
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Die Untersuchung kausaler Zusammenhänge in komplexen dynamischen Systemen spielt in der Wissenschaft eine immer wichtigere Rolle. Ziel dieses aktuellen, interdisziplinären Forschungsbereiches ist ein grundlegendes, tiefes Verständnis der vorherrschenden Prozesse und deren Wechselwirkungen in solchen Systemen. Die Untersuchung von Zeitreihen mithilfe moderner Kopplungsanalysemethoden liefert dabei Möglichkeiten zur Modellierung der betreffenden Systeme und somit bessere Vorhersagemethoden und fortgeschrittene Interpretationsmöglichkeiten der Ergebnisse. In der vorliegenden Arbeit werden zunächst einige existierende Kopplungsmaße mit ihren jeweiligen Anwendungsgebieten vorgestellt. Eine Gemeinsamkeit dieser Maße liegt in der Voraussetzung stationärer Zeitreihen, um die Anwendbarkeit zu gewährleisten. Daher wird im Verlauf der Dissertation eine Möglichkeit zur Erweiterung solcher Maße vorgestellt, die eine Kopplungsanalyse mit einer sehr hohen Zeitauflösung und somit auch die Untersuchung nichtstationärer, transienter Ereignisse ermöglicht. Die Erweiterung basiert auf der Verwendung von Ensembles von Messreihen und der Schätzung der jeweiligen Maße über das Ensemble anstatt über die Zeit. Dies ermöglicht eine Zeitauflösung bei der Analyse in der Größenordnung der Abtastrate des ursprünglichen Signals, die nur von der Art der verwendeten Kopplungsmaße abhängt. Der Ensemble-Ansatz wird auf verschiedene Kopplungsmaße angewandt. Zunächst werden die Methoden ausführlich an verschiedenen theoretischen Modellen und unter verschiedenen Bedingungen getestet. Anschließend erfolgt eine zeitaufgelöste Kopplungsanalyse kardiovaskulärer Zeitreihen, die während transienter Ereignisse aufgenommen wurden. Die Ergebnisse dieser Analyse bestätigen zum einen aktuelle Studienresultate, liefern aber auch neue Erkenntnisse, die es in Zukunft ermöglichen können, Modelle des Herz-Kreislauf-Systems zu erweitern und zu verbessern.The analysis of causal relationships in complex dynamic systems plays a more and more important role in various scientific fields. The aim of this current, interdisciplinary field of research is a fundamental, deep understanding of predominant processes and their interactions in such systems. The study of time series using modern coupling analysis tools allows the modelling of the respective systems and thus better prediction methods and advanced interpretation possibilities for the results. In this work, initially some existing coupling measures and their fields of application are introduced. One trait these measures have in common is the requirement of stationary time series to ensure their applicability. Therefore, in the course of this thesis a possibility to extend these measures is presented, which allows a coupling analysis with a high temporal resolution and thus also the analysis of transient, nonstationary events. The extension is based on the use of ensembles of time series and the calculation of the respective measures across these ensembles instead of across time. This allows for a temporal resolution of the same order of magnitude as the sampling rate in the original signal. The resolution only depends on the kind of coupling analysis method employed. The ensemble extension is applied to different coupling measures. To begin with, the regarded tools are tested on various theoretical models and under different conditions. This is followed by a coupling analysis of cardiovascular time series recorded during transient events. The results on the one hand confirm topical study outcomes and on the other hand deliver new insights, which will allow to extend and improve cardiovascular system models in the future.
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Alexandrescu, Marian-Dan. "Outils pour la simulation des fautes transitoires". Grenoble INPG, 2007. http://www.theses.fr/2007INPG0084.
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Les événements singuliers proviennent de l'interaction d'une particule énergétique avec un circuit microélectronique. Ces perturbations peuvent modifier d'une manière imprévue le fonctionnement du circuit et introduire des fautes. La sensibilité des circuits augmentant à chaque nouvelle génération technologique, il devient nécessaire de disposer d'outils spécifiques pour la conception des circuits durcis face aux événements singuliers. Les travaux de cette thèse visent à étendre la compréhension de ces phénomènes et à proposer des outils CAO pour faciliter l'analyse de ces problèmes dans les circuits actuels. Nous avons développé des méthodologies pour l'analyse du comportement des cellules de la bibliothèque standard et des outils pour la simulation accélérée des fautes et pour l'évaluation probabiliste des effets singuliers. Les résultats fournis par ces outils vont permettre aux concepteurs d'évaluer et de choisir des méthodes adéquates pour améliorer la fiabilité des circuits intégrésSingle Events (SE) are produced by the interaction of charged particles with the transistors of a microelectronic circuit. These perturbations may alter the functioning of the circuit and cause logic faults and errors. As the sensitivity of circuits increases for each technological evolution, specific tools are needed for the design of hardened circuits. This thesis aims at furthering the comprehension of the phenomena and proposes EDA tools to help the analysis of these problems in today's ICs. We have developed methodologies for the characterization of the cells from the standard library and tools for accelerated fault simulation and probabilistic analysis of single events. The results provided by these tools allow the designer to correctly evaluate the sensitivity of his design and select the most adequate methods to improve the reliability of ICs
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Varghese, Rajan Albert. "Transient Waveform Clustering : Developing efficient data analytics toolchains applying unsupervised machine learning techniques on power quality events". Thesis, Linnéuniversitetet, Institutionen för fysik och elektroteknik (IFE), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-105742.
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High Voltage Direct Current (HVDC) transmission systems appropriate for bulk power transfer to meet increasing power demands and ideal for interconnecting power systems with distant renewable sources of energy without any chances of loss synchronism, efficiency, and reliability. The main obstacle is however connected with the DC grid protection where the timely diagnosis of faults is critical to prevent any rapid built-up leading to failure of the power electronic devices. Monitoring the Power Quality (PQ) necessitates establishing novel criteria and techniques to deal with the abundance of data that are ever-growing with data flow from sensors and measuring units in the electric grid. This study developed a scalable and efficient clustering methodology for a transient waveform database from a HVDC station. The output could help HVDC Service better characterize the data and develop qualitative criteria for monitoring and analytics. The thesis expects to contribute towards a sustainable and reliable electric grid.
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Hoagland, Steven. "TRANSIENT-BASED RISK ANALYSIS OF WATER DISTRIBUTION SYSTEMS". UKnowledge, 2016. http://uknowledge.uky.edu/ce_etds/39.
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Water distribution system utilities must be able to maintain a system’s assets (i.e., pumps, tanks, water mains, etc.) in good working condition in order to provide adequate water quantity and quality to its customers. Various asset management approaches are employed by utilities in order to make optimal decisions regarding the renewal of system components. Part of a good asset management approach is performing a comprehensive risk analysis which consists of considering all potential ways in which the system may fail, the likelihood failure of for each scenario, and the consequences of said failure. This study investigates a water distribution system’s risk of failure due to both acute transient events (e.g., pump trip) and standard pressure fluctuations due to daily system operations. Such an analysis may be useful in optimal decision making such as asset monitoring, scheduling of condition assessments or system renewal projects, policy implementation, and investment priorities in order to keep the utility’s total costs at a minimum. It may also be useful as a precautionary measure to help prevent catastrophic failures such as large main blowouts for which the utility would incur substantial costs, both direct and indirect.
As part of this thesis, a database of water distribution system models is used to analyze the effects of an acute transient event for different system configurations. The database was created at the University of Kentucky and has been made available to the research community to test newly developed algorithms for various studies including optimal system operations and optimal system design.
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Mól, Antônio Carlos de Abreu, e Instituto de Engenharia Nuclear. "Um sistema de identificação de transientes com inclusão de ruídos e indicação de eventos desconhecidos". Instituto de Engenharia Nuclear, 2002. http://carpedien.ien.gov.br:8080/handle/ien/1917.
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Esta tese apresenta uma metodologia, baseada em Redes Neurais Artificiais (RNA), para a identificação de transientes a qual permite tanto uma identificação dinâmica quanto a resposta “Não Sei” para eventos desconhecidos. O método usa duas RNA’s. A primeira rede é responsável pela identificação dinâmica, utilizando como entradas um pequeno conjunto (através de uma janela temporal móvel) dos valores recentes das variáveis de estado. A outra rede é utilizada para validar a identificação feita pela primeira através da identificação de cada variável, emitindo assim a resposta “Não Sei” para eventos desconhecidos. No processo de validação foi utilizado um conjunto de 15 acidentes postulados para uma usina nuclear PWR, gerados por simulação computacional e com ruído superposto ao dados. Os resultados obtidos mostraram a capacidade do método em analisar sistemas dinâmicos e emitir resposta “Não Sei” para eventos desconhecidos.
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Tueros-cuadros, Edith. "Modulação de raios cósmicos em diferentes escalas temporais e sua variação com eventos transientes solares". Universidade Presbiteriana Mackenzie, 2016. http://tede.mackenzie.br/jspui/handle/tede/1309.
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Previous issue date: 2016-02-02Fundação de Amparo a Pesquisa do Estado de São Paulo
Cosmic rays are strongly influenced by solar, geomagnetic and atmospheric phenomena. CARPET detector, conceived for cosmic rays observation with energies in the range between 105 - 1012 eV, is an important tool for the study of these phenomena. The Earth s atmosphere conditions are also affected by changes in the cosmic rays flux, therefore, cosmic rays characterization is important to define physical and chemical conditions of our atmosphere. To characterize the cosmic rays flux variations, detected on the ground, prior elimination of atmospheric pressure and temperature effects on ground level is needed, thus, data recorded by meteorological instruments on CASLEO were used for that corrections. To eliminate the effect of temperature through the whole vertical atmosphere it was applied the integral and the mass-average temperature method by using vertical temperature profiles. Both methods were tested using CARPET-TEL data for the year 2009, this data were previously corrected by pressure influences. The mass-average temperature method shows a better response when comparing the corrected CARPET date with neutron monitor observations .The whole cosmic rays flux data analysis, for CARPET-TEL data corrected by integral method (for the period 2006/04/01 - 2014/06/30), shows an anti-correlation with sunspot number and a clear seasonal variation after 2008. Two Forbush decreases (FD), were detected by CARPET which were produced by geo-effective CMEs. Both FD onsets coincided with the interplanetary shock instant, which preceded intense geomagnetic storms. With these results, we can reinforce that CARPET is an important tool to study long and short term cosmic rays behavior, because it has a similar response to experiments that operates at atmosphere particle energy ranges.
Os raios cósmicos são fortemente influenciados pelos fenômenos solares, geomagnéticos e atmosféricos. O detector CARPET, concebido para a observação dos raios cósmicos com energias na faixa compreendida entre 105 e 1012 eV, é uma ferramenta importante para o estudo desses fenômenos. As condições da nossa atmosfera são também afetadas pelas variações no fluxo de raios cósmicos que chegam a Terra, portanto sua caracterização é importante para se definir as condições físicas e químicas da mesma. Para caracterizar as variações do fluxo de raios cósmicos a partir de observações no solo é necessário a eliminação prévia da influência dos efeitos da pressão e temperatura atmosférica na superfície, para tal foram utilizados dados meteorológicos obtidos no CASLEO. Para a eliminação do efeito da temperatura ao longo de toda atmosfera foram utilizados o método integral e o método de temperatura ponderada pela massa que utilizam perfis verticais de temperatura. Os dois métodos foram testados para o ano de 2009 com os dados do canal TEL do CARPET previamente corrigidos pela pressão, sendo que o método de temperatura ponderada pela massa apresentou uma resposta melhor ao se comparar os dados corrigidos com os dados observados com monitores de nêutrons. A análise de todos os dados do fluxo raios cósmicos do canal TEL do CARPET (1/04/2006 a 30/06/2014) corrigidos pelo método integral, mostra a anti-correlação com o número de manchas solares, e uma variação sazonal pronunciada após 2008. Foram detectados dois decréscimos Forbush (FD) produzidos por CMEs geo-efetivos. O início de ambos FD coincidiu com o instante do choque interplanetário, que antecedeu tempestades geomagnéticas intensas. Com estes resultados reforçamos que o CARPET é uma ferramenta importante para estudo das modulações de raios cósmicos de longo e curto prazo porque apresenta uma resposta semelhante com os experimentos que fazem observações em outras faixas de energia.
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Guan, Ling. "Autonomic nervous system parameters to predict the occurrence of ischemic events after transient ischemic attack or minor stroke". Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/63274.
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The full abstract for this thesis is available in the body of the thesis, and will be available when the embargo expires.Medicine, Faculty of
Experimental Medicine, Division of
Medicine, Department of
Graduate
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Ribeiro, Ivandro da Silva. "Modelagem e caracterização da propagação de pulsos transientes causados por radiação ionizante". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2010. http://hdl.handle.net/10183/31119.
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A propagação de eventos transientes na lógica combinacional é estudada através da simulação elétrica do circuito, utilizando-se o simulador Hspice. Uma das fontes de falhas transientes é o pulso transiente causado por partículas ionizantes que atingem o circuito. O estudo é centrado nas propriedades de mascaramento elétrico das portas lógicas. Estuda-se a propagação do pulso transiente através de cada estágio da lógica até que alcance um elemento da memória. A partir do estudo das propriedades de mascaramento elétrico, propõe-se um modelo simples para a degradação e ampliação de um pulso transiente enquanto este é propagado através de uma cadeia de portas lógicas. O modelo considera as propriedades elétricas das portas, utilizando como parâmetro principal da modelagem o tempo de propagação (atraso) da porta lógica. O modelo é computacionalmente eficiente e adequado para implementação em ferramentas de auxilio de projeto automatizadas, como ferramentas de timing analysis. A ferramenta timing analysis poderia então executar um algoritmo para percorrer todos os nós de um circuito, determinando os nós mais sensíveis, ajudando a estimar e reduzir a taxa de falhas transientes do circuito. Visando no futuro, testar o modelo e o comportamento de circuitos combinacional sobre efeito de partículas radioativas, foram estudadas algumas arquiteturas existentes capazes de medir a largura dos pulsos transientes nos circuitos combinacionais on-chip, para compararmos com o modelo analítico proposto e os comportamentos elétricos obtidos através de simulação Hspice.Single Event Transients in Combinatorial Logic are studied using spice-level circuit simulation. The study is centered on the electrical masking properties of the gates. The propagation of the transient through each stage of logic until it reaches a memory element is characterized. Both duration and amplitude of the transient pulse are attenuated as it propagates through the logic gates. A simple, first order model for the degradation of a transient pulse as it is propagated through a chain of logic gates is proposed. The model considers the electrical properties of the logic gates through which the pulse propagates. The model is computationally efficient and intended to be implemented in a timing analysis tool. The timing analysis tool could then implement an algorithm to traverse all circuit nodes, determining the most sensitive nodes, helping to estimate and reduce the soft error failure rate of the whole circuit. Aiming at the future, test the model and the behavior of combinatorial circuits effect on radioactive particles, was studied some existing architectures capable of measuring the width of transient pulses in combinatorial circuits on-chip, to compare with the proposed analytical model and the electrical behaviors obtained by Hspice simulation.
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Kuttan, Chandrika Unnikrishnan. "Development of a New Algorithm for Automatic Detection and Rating of Squeak and Rattle Events in Automobiles". University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1248893155.
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Truyen, David. "Etude par simulation composant 3D des effets singuliers SEU et SET induits par ions lourds sur le noeud technologique CMOS bulk 180 nm". Montpellier 2, 2007. http://www.theses.fr/2007MON20139.
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Osborne, William Dale. "NPSNET : an accurate low-cost technique for real-time display of transient events : vehicle collisions, explosions and terrain modifications". Thesis, Monterey, California. Naval Postgraduate School, 1991. http://hdl.handle.net/10945/26651.
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Trueheart, Matthew Everett. "Simulating hydraulic interdependence between bridges along a river corridor under transient flood conditions". ScholarWorks @ UVM, 2019. https://scholarworks.uvm.edu/graddis/1042.
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The interactions between rivers, surrounding hydrogeological features, and hydraulic structures such as bridges are not well-established or understood at the network scale, especially under transient conditions. The cascading hydraulic effects of local perturbations up- and downstream of the site of perturbation may have significant, unexpected, and far-reaching consequences, and therefore often cause concern among stakeholders. The up- and downstream hydraulic impacts of a single structural modification may extend much farther than anticipated, especially in extreme events. This work presents a framework and methodology to perform an analysis of interdependent bridge-stream interactions along a river corridor. Such analysis may help prioritize limited resources available for bridge and river rehabilitations, allow better-informed cost/benefit analysis, facilitate holistic design of bridges, and address stakeholder concerns raised in response to planned bridge and infrastructure alterations. The stretch of the Otter Creek from Rutland to Middlebury, VT, is used as a test bed for this analysis.
A two-dimensional hydraulic model is used to examine the effects individual structures have on the bridge-stream network, particularly during extreme flood events. Results show that, depending on their characteristics, bridges and roadways may either attenuate or amplify peak flood flows up- and downstream, or have little to no impact at all. Likewise, bridges may or may not be sensitive to any changes in discharge that result from perturbation of existing structures elsewhere within the network. Alterations to structures that induce substantial backwaters may result in the most dramatic impacts to the network, which can be either positive or negative. Structures that do not experience relief (e.g., roadway overtopping) may be most sensitive to network perturbations.
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Gnawali, Krishna Prasad. "EMERGING MEMORY-BASED DESIGNS AND RESILIENCY TO RADIATION EFFECTS IN ICS". OpenSIUC, 2020. https://opensiuc.lib.siu.edu/dissertations/1863.
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The performance of a modern computing system is improving with technology scaling due to advancements in the modern semiconductor industry. However, the power efficiency along with reliability does not scale linearly with performance efficiency. High leakage and standby power in sub 100 nm technology are critical challenges faced by circuit designers. Recent developments in device physics have shown that emerging non-volatile memories are very effective in reducing power dissipation because they eliminate stand by power and exhibit almost zero leakage powerThis dissertation studies the use of emerging non-volatile memory devices in designing circuit architecture for improving power dissipation and the performance of the computing system. More specically, it proposes a novel spintronic Ternary Content AddressableMemory (TCAM), a novel memristive TCAM with improved power and performance efficiency. Our experimental evaluation on 45 nm technology for a 256-bit word-size spintronic TCAM at a supply voltage of 1 V with a sense margin of 50 mV show that the delay is lessthan 200 ps and the per-bit search energy is approximately 3 fJ. The proposed spintronic TCAM consumes at least 30% less energy when compared to state-of-the-art TCAM designs. The search delay on a 144-bit proposed memristive TCAM at a supply voltage of 1 V and a sense margin of 140 mV is 175 ps with per bit search energy of 1.2 fJ on a 45 nm technology. It is 1.12 x times faster and dissipates 67% less search energy per bit than the fastest existing 144-bit MTCAM design.Emerging non-volatile memories are well known for their ability to perform fast analog multiplication and addition when they are arranged in crossbar fashion and are especially suited for neural network applications. However, such systems require the on-chip implementation of the backpropagation algorithm to accommodate process variations. This dissertation studies the impact of process variation in training memristive neural network architecture. It proposes a low hardware overhead on-chip implementation of the backpropagation algorithm that utilizes effectively the very dense memristive cross-bar arrayand is resilient to process variations.Another important issue that needs a careful study due to shrinking technology node is the impact of space or terrestrial radiation in Integrated Circuits (ICs) because the probability of a high energy particle causing an error increases with a decrease in thethreshold voltage and the noise margin. Moreover, single-event effects (SEEs) sensitivity depends on the set of input vectors used at the time of testing due to logical masking. This dissertation analyzes the impact of input test set on the cross section of the microprocessorand proposes a mechanism to derive a high-quality input test set using an automatic test pattern generation (ATPG) for radiation testing of microprocessors arithmetic and logical units..
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Bartra, Walter Enrique Calienes. "Modelamento do single-Event effiects em circuitos de memória FDSOI". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/159203.
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Este trabalho mostra a comparação dos efeitos das falhas provocadas pelos Single-Event Effects em dispositivos 28nm FDSOI, 28nm FDSOI High-K e 32nm Bulk CMOS e células de memória 6T SRAM feitas com estes dispositivos. Para conseguir isso, foram usadas ferramentas TCAD para simular falhas transientes devido a impacto de íons pesados a nível dispositivo e nível circuito. As simulações neste ambiente tem como vantagem a simulação dos fatos e mecanismos que produz as falhas transientes e seus efeitos nos dispositivos, além de também servir para projetar virtualmente estes dispositivos e caraterizar eles para estas simulações. Neste caso, foram projetados três dispositivos para simulação: um transistor NMOS de 32nm Bulk, um transistor NMOS de 28nm FDSOI e um transistor NMOS de 28nm FDSOI High-K para fazer comparações entre eles. Estes dispositivos foram projetados, caraterizados e testados contra o impacto de íons pesados a níveis dispositivo e circuito. Como resultado obtido, transistor Bulk de 32nm teve, no pior caso, uma carga coletada de 7.57 e 7.19 vezes maior que a carga coletada pelo dispositivo FDSOI de 28nm e FDSOI High-K de 28nm respectivamente atingido pelo mesmo íon pesado de 100MeV-cm2/mg. Com estes dados foi possível modelar o comportamento da carga coletada de ambos dispositivos usando este íon pesado, atingindo os terminais de Fonte e Dreno em distintos lugares e ângulos. Usando a mesma ferramenta e os dados obtidos de carga coletada pelos testes anteriores, foram projetadas células de memória SRAM de 6 transistores. Isso foi para testar elas contra os efeitos do impacto de íons pesados nos transistores NMOS de armazenagem da dados. Neste caso, a Transferência Linear de Energia (LET) do íon necessária para fazer que o dado armazenado na SRAM Bulk mude é 12.8 vezes maior que no caso da SRAM FDSOI e 10 maior no caso da SRAM FDSOI High-K, embora a quantidade de carga coletada necessária para que o dado mude em ambas células seja quase a mesma. Com estes dados foi possível modelar os efeitos dos íons pesados em ambos circuitos, descobrir a Carga Crítica destes e qual é o mínimo LET necessário para que o dado armazenado nestas SRAMs mude.This work shows a comparison of faults due to Single-Event Effects in 28nm Fully Depleted SOI (FDSOI), 28nm FDSOI High-K and 32nm Bulk CMOS devices, and in 6T SRAM memory cells made with these devices. To provide this, was used TCAD tools to simulate transient faults due to heavy ion impacts on device and circuit levels. The simulations in that environment have the advantage to simulate the facts and mechanisms which produce the transient faults and this effects on the electronic devices, it also allow to simulate the virtual device fabrication and to characterize them. In this case, two devices were created for the simulations: a 32nm Bulk NMOS transistor and a 28nm FDSOI NMOS transistor for compare them. These devices were created, characterized and tested against heavy ion impacts at device and circuit levels. The results show that 32nm Bulk transistor has, in the worst case, a collected charge 7.57 and 7.19 times greater than the 28nm FDSOI and 28nm FDSOI High-K respectively collected charge with the same 100MeV-cm2/mg heavy ion. With these data it was possible to model the behavior of the collected charge in both devices with the same heavy-ion, reach the Source and Drain Terminal in different places and angles. Using the same tools and the obtained collected charge data of previous simulations, it was designed 6 transistors SRAM Memory Cells. That is done to test these circuits against the heavy ion effects on the data-storage NMOS transistor. In this case, the necessary Ion Linear Energy Transfer (LET) to flip the Bulk SRAM is 12.8 greater than the FDSOI SRAM and 10 times greater than the FDSOI High- K SRAM case, although the amount of charge to flip the cells is almost the same in both cases. With these data it was possible to model the heavy-ion effects in both circuits, discover the Critical Charge of them and the minimum LET to flips these SRAMs.
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Simionovski, Alexandre. "Sensor de corrente transiente para detecção do SET com célula de memória dinâmica". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2012. http://hdl.handle.net/10183/61132.
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Esta dissertação trata do projeto e avaliação de um novo circuito sensor de corrente com célula de memória dinâmica para a detecção de correntes transientes em circuitos integrados CMOS, provocadas pela incidência de partículas ionizantes. As propostas previamente existentes na literatura são avaliadas e suas deficiências são apontadas. É apresentada a topologia e o modo de funcionamento do novo circuito, juntamente com o detalhamento do projeto das versões destinadas à monitoração dos transistores PMOS e NMOS. É apresentado o layout do circuito final em tecnologia 130 nm, destinado à prototipação pelo programa MOSIS, contendo os sensores, os transistores-alvo, os estágios de saída e os circuitos de proteção contra os efeitos da eletricidade estática necessários. Os resultados obtidos através de simulação mostram que o novo circuito proporciona uma redução na área de silício necessária para a implementação, bem como um menor consumo de corrente quiescente em relação às propostas anteriores.This dissertation deals with the design and evaluation of a new current sensor circuit with dynamic memory cell intended to detect transient currents caused by incidence of ionizing particles in CMOS integrated circuits. Circuits previously proposed are analyzed and their drawbacks are pointed out. The new circuit topology and working principle is presented, along with the detailed design of the versions intended to monitoring PMOS and NMOS transistors. The final circuit is laid out in a 130 nm technology, intended to be prototyped through the MOSIS program. The complete design contains the sensor circuits, target transistors, output stages and electrostatic discharge protection circuitry. Results obtained by post layout simulation shown that the new circuit provides a reduction on silicon area and a smaller quiescent current consumption compared to previous circuits.
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Oesterreich, Mark H. "Transient response analysis of the 72 Inch TAC-4 ruggedized shipboard rack subjected to an underwater explosion event". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1998. http://handle.dtic.mil/100.2/ADA354298.
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Thesis (Degree of Mechanical Engineer and M.S. in Mechanical Engineering) Naval Postgraduate School, June 1998."June 1998." Thesis advisor(s): Young S. Shin. Includes bibliographical references (p. 97). Also available online.
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LANGE, THOMAS. "New Reliable Operation Infrastructure for Dynamic, High-dependability Applications". Doctoral thesis, Politecnico di Torino, 2021. http://hdl.handle.net/11583/2935598.
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Evans, Adrian. "Techniques d'abstraction pour l'analyse et la mitigation des effets dus à la radiation". Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENT035/document.
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Les effets dus à la radiation peuvent provoquer des pannes dans des circuits intégrés. Lorsqu'une particule subatomique, fait se déposer une charge dans les régions sensibles d'un transistor cela provoque une impulsion de courant. Cette impulsion peut alors engendrer l'inversion d'un bit ou se propager dans un réseau de logique combinatoire avant d'être échantillonnée par une bascule en aval.Selon l'état du circuit au moment de la frappe de la particule et selon l'application, cela provoquera une panne observable ou non. Parmi les événements induits par la radiation, seule une petite portion génère des pannes. Il est donc essentiel de déterminer cette fraction afin de prédire la fiabilité du système. En effet, les raisons pour lesquelles une perturbation pourrait être masquée sont multiples, et il est de plus parfois difficile de préciser ce qui constitue une erreur. A cela s'ajoute le fait que les circuits intégrés comportent des milliards de transistors. Comme souvent dans le contexte de la conception assisté par ordinateur, les approches hiérarchiques et les techniques d'abstraction permettent de trouver des solutions.Cette thèse propose donc plusieurs nouvelles techniques pour analyser les effets dus à la radiation. La première technique permet d'accélérer des simulations d'injections de fautes en détectant lorsqu'une faute a été supprimée du système, permettant ainsi d'arrêter la simulation. La deuxième technique permet de regrouper en ensembles les éléments d'un circuit ayant une fonction similaire. Ensuite, une analyse au niveau des ensemble peut être faite, identifiant ainsi ceux qui sont les plus critiques et qui nécessitent donc d'être durcis. Le temps de calcul est ainsi grandement réduit.La troisième technique permet d'analyser les effets des fautes transitoires dans les circuits combinatoires. Il est en effet possible de calculer à l'avance la sensibilité à des fautes transitoires de cellules ainsi que les effets de masquage dans des blocs fréquemment utilisés. Ces modèles peuvent alors être combinés afin d'analyser la sensibilité de grands circuits. La contribution finale de cette thèse consiste en la définition d'un nouveau langage de modélisation appelé RIIF (Reliability Information Ineterchange Format). Ce langage permet de décrire le taux des fautes dans des composants simples en fonction de leur environnement de fonctionnement. Ces composants simples peuvent ensuite être combinés permettant ainsi de modéliser la propagation de leur fautes vers des pannes au niveau système. En outre, l'utilisation d'un langage standard facilite l'échange de données de fiabilité entre les partenaires industriels.Au-delà des contributions principales, cette thèse aborde aussi des techniques permettant de protéger des mémoires associatives ternaires (TCAMs). Les approches classiques de protection (codes correcteurs) ne s'appliquent pas directement. Une des nouvelles techniques proposées consiste à utiliser une structure de données qui peut détecter, d'une manière statistique, quand le résultat n'est pas correct. La probabilité de détection peut être contrôlée par le nombre de bits alloués à cette structure. Une autre technique consiste à utiliser un détecteur de courant embarqué (BICS) afin de diriger un processus de fond directement vers le région touchée par une erreur. La contribution finale consiste en un algorithme qui permet de synthétiser de la logique combinatoire afin de protéger des circuits combinatoires contre les fautes transitoires.Dans leur ensemble, ces techniques facilitent l'analyse des erreurs provoquées par les effets dus à la radiation dans les circuits intégrés, en particulier pour les très grands circuits composés de blocs provenant de divers fournisseurs. Des techniques pour mieux sélectionner les bascules/flip-flops à durcir et des approches pour protéger des TCAMs ont étés étudiéesThe main objective of this thesis is to develop techniques that can beused to analyze and mitigate the effects of radiation-induced soft errors in industrialscale integrated circuits. To achieve this goal, several methods have been developedbased on analyzing the design at higher levels of abstraction. These techniquesaddress both sequential and combinatorial SER.Fault-injection simulations remain the primary method for analyzing the effectsof soft errors. In this thesis, techniques which significantly speed-up fault-injectionsimulations are presented. Soft errors in flip-flops are typically mitigated by selectivelyreplacing the most critical flip-flops with hardened implementations. Selectingan optimal set to harden is a compute intensive problem and the second contributionconsists of a clustering technique which significantly reduces the number offault-injections required to perform selective mitigation.In terrestrial applications, the effect of soft errors in combinatorial logic hasbeen fairly small. It is known that this effect is growing, yet there exist few techniqueswhich can quickly estimate the extent of combinatorial SER for an entireintegrated circuit. The third contribution of this thesis is a hierarchical approachto combinatorial soft error analysis.Systems-on-chip are often developed by re-using design-blocks that come frommultiple sources. In this context, there is a need to develop and exchange reliabilitymodels. The final contribution of this thesis consists of an application specificmodeling language called RIIF (Reliability Information Interchange Format). Thislanguage is able to model how faults at the gate-level propagate up to the block andchip-level. Work is underway to standardize the RIIF modeling language as well asto extend it beyond modeling of radiation-induced failures.In addition to the main axis of research, some tangential topics were studied incollaboration with other teams. One of these consisted in the development of a novelapproach for protecting ternary content addressable memories (TCAMs), a specialtype of memory important in networking applications. The second supplementalproject resulted in an algorithm for quickly generating approximate redundant logicwhich can protect combinatorial networks against permanent faults. Finally anapproach for reducing the detection time for errors in the configuration RAM forField-Programmable Gate-Arrays (FPGAs) was outlined