Dissertations / Theses on the topic 'Sensor failures'
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Paturu, Raghunatha Rao Nityananda Suresh. "Path Planning under Failures in Wireless Sensor Networks." Thesis, North Dakota State University, 2013. http://hdl.handle.net/10365/22971.
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This paper explores how an all pair shortest path can be obtained in a wireless sensor network when sensors fail. Sensors are randomly deployed in a predefined geographical area, simulating the deployment of sensors from an airplane, and finding shortest path between all the sensors deployed based on distance. A major problem to address in wireless sensor networks is the impact of sensor failures on existing shortest paths in the network. An application is developed to simulate a network and find shortest paths affected by a sensor failure and find alternative shortest path. When a sensor fails, all the shortest paths and all the remaining sensors in the network are checked to see if the sensor failure has any impact on the network. Alternative shortest path is calculated for those paths affected by sensor failures.
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Thimmapuram, Aravind. "Distributed recovery of actor failures in wireless sensor and actor networks /." Available to subscribers only, 2008. http://proquest.umi.com/pqdweb?did=1559859581&sid=7&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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Philipps, Joseph Caleb. "Sensor characterization for long-term remote monitoring of bridge piers." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/4907.
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Thesis (M.S.)--University of Missouri-Columbia, 2007.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on April 2, 2008) Includes bibliographical references.
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Vemulapalli, Shanthi. "Mobility-based route recovery from multiple node failures in movable sensor networks /." Available to subscribers only, 2009. http://proquest.umi.com/pqdweb?did=1967797561&sid=5&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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VEMULAPALLI, SHANTHI. "MOBILITY-BASED ROUTE RECOVERY FROM MULTIPLE NODE FAILURES IN MOVABLE SENSOR NETWORKS." OpenSIUC, 2009. https://opensiuc.lib.siu.edu/theses/80.
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In wireless sensor networks (WSNs), maintaining connectivity with the sink node is a crucial issue to collect data from sensors without any interruption. While sensors are typically deployed in abundance to tolerate possible node failures, a number of such failures within the same region simultaneously may result in losing the connectivity with the sink node which eventually reduces the quality and efficiency of the network operation. Given that WSNs are deployed in inhospitable environments, such multiple node failures are very likely due to storms, volcano eruptions, floods, etc. To recover from these multiple node failures, in this thesis, we first present a local partition detection algorithm which makes the sensors aware of the partitioning in the network. We then utilize this information to recover the paths by exploiting sensor mobility. The idea is to locate the failed nodes by keeping complete routing information from each sensor to the sink node and move some of the sensors to such locations to re-establish the routes with the sink node. When performing the recovery, we make sure that the least number of nodes will be moving so that total movement distance can be minimized to improve the lifetime of the WSN. Our proposed approach depends only on the local information to not only minimize the messaging overhead on the sensors but also to ensure the scalability when large-scale Failures and larger networks are considered. The effectiveness of the proposed route recovery approach is validated through simulation experiments.
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Kaur, Amardeep. "Vehicle positioning using image processing." Diss., Rolla, Mo. : Missouri University of Science and Technology, 2009. http://scholarsmine.mst.edu/thesis/pdf/Kaur_09007dcc80665391.pdf.
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Thesis (M.S.)--Missouri University of Science and Technology, 2009.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed May 27, 2009) Includes bibliographical references (p. 72-74).
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Zhang, Guangfan. "Optimum Sensor Localization/Selection In A Diagnostic/Prognostic Architecture." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/6846.
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Optimum Sensor Localization/Selection in
A Diagnostic/Prognostic Architecture
Guangfan Zhang
107 Pages
Directed by Dr. George J. Vachtsevanos
This research addresses the problem of sensor localization/selection for fault diagnostic purposes in Prognostics and Health Management (PHM)/Condition-Based Maintenance (CBM) systems. The performance of PHM/CBM systems relies not only on the diagnostic/prognostic algorithms used, but also on the types, location, and number of sensors selected. Most of the research reported in the area of sensor localization/selection for fault diagnosis focuses on qualitative analysis and lacks a uniform figure of merit. Moreover, sensor localization/selection is mainly studied as an open-loop problem without considering the performance feedback from the on-line diagnostic/prognostic system. In this research, a novel approach for sensor localization/selection is proposed in an integrated diagnostic/prognostic architecture to achieve maximum diagnostic performance.
First, a fault detectability metric is defined quantitatively. A novel graph-based approach, the Quantified-Directed Model, is called upon to model fault propagation in complex systems and an appropriate figure-of-merit is defined to maximize fault detectability and minimize the required number of sensors while achieving optimum performance.
Secondly, the proposed sensor localization/selection strategy is integrated into a diagnostic/prognostic system architecture while exhibiting attributes of flexibility and scalability. Moreover, the performance is validated and verified in the integrated diagnostic/prognostic architecture, and the performance of the integrated diagnostic/prognostic architecture acts as useful feedback for further optimizing the sensors considered. The approach is tested and validated through a five-tank simulation system.
This research has led to the following major contributions:
??generalized methodology for sensor localization/selection for fault diagnostic purposes.
??quantitative definition of fault detection ability of a sensor, a novel Quantified-Directed Model (QDG) method for fault propagation modeling purposes, and a generalized figure of merit to maximize fault detectability and minimize the required number of sensors while achieving optimum diagnostic performance at the system level.
??novel, integrated architecture for a diagnostic/prognostic system.
??lidation of the proposed sensor localization/selection approach in the integrated diagnostic/prognostic architecture.
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Rusek, Bartosz [Verfasser]. "Digital Modeling and Simulations of High Voltage Circuit Breaker Failures for Optimization of Sensor Technique / Bartosz Rusek." Aachen : Shaker, 2007. http://d-nb.info/1166512703/34.
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An, Younghwan. "A design of fault tolerant flight control systems for sensor and actuator failures using on-line learning neural networks." Morgantown, W. Va. : [West Virginia University Libraries], 1998.
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Thesis (Ph. D.)--West Virginia University, 1998.Title from document title page. Document formatted into pages; contains xix, 179 p. : ill. Includes abstract. Includes bibliographical references (p. 173-178).
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Abhinav, Abhinav. "Sensor Failure Mode Detection and Self-Validation." University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1227254283.
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Castro, Bruno Albuquerque de [UNESP]. "Localização de descargas parciais em transformadores de potência por meio de sensores piezelétricos de baixo custo e sistemas inteligentes." Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/138944.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O monitoramento e a localização precoce de descargas parciais em aparelhos de alta tensão, como nos transformadores de potência, são de fundamental importância para a prevenção de problemas funcionais associados à degradação contínua dos materiais que compõe o isolamento elétrico destes tipos de aparelho. Alguns fatores críticos na operação dos transformadores, como o funcionamento em sobrecarga, superaquecimento, transitórios e sinais elétricos de grande conteúdo harmônico vinculados a sistemas chaveados, em longo prazo, fazem com que o sistema de isolação de um transformador apresente degradação de suas propriedades físicas e químicas intrínsecas aos diversos tipos de materiais utilizados para esta finalidade e, deste modo, surjam descargas parciais. Este trabalho teve como objetivo aplicar sensores piezelétricos de baixo custo para a identificação e localização de descargas parciais em transformadores de potência por meio de sistemas inteligentes do tipo Redes Neurais e sistema de inferência neuro fuzzy adaptativos. Ambos os sistemas foram treinados com algumas métricas de processamento de sinais e os resultados de erro médio de localização chegaram na casa dos milímetros. Variou-se o número de sensores acoplados e foi realizado um estudo sobre os resultados de localização obtidos.
Partial discharge damages in power transformers require high cost monitoring procedures based on corrective maintenance or even interruptions of the power system. The development of online non-invasive monitoring systems to detect partial discharges in power transformers has great relevance since it can reduce significant maintenance costs. Some critical factors in the operation of transformers such as overload, nonlinear loads, transient voltage surges by atmospheric origin and switching, can make the insulation system of transformers to lose their physical and chemical properties. Therefore, these operating conditions can cause early deterioration of the insulation, causing internal partial discharges that may develop into major defects and thus shorten the useful life of electrical equipment. This research aimed to apply a low cost piezoelectric sensors for partial discharge identification and location in power transformers through intelligent systems such as neural networks and adaptive fuzzy inference system. Both systems were trained with some signal processing metrics and the results for location error was in the region of millimeters. It was varied the number of coupled sensors and a study was conducted on the obtained location results.
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Smeltz, Jeremy M. Valerius Andrew J. "Sensor failure detection through introspection." Monterey, Calif. : Naval Postgraduate School, 2007. http://bosun.nps.edu/uhtbin/hyperion-image.exe/07Jun%5FSmeltz.pdf.
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Thesis (M.S. in Computer Science)--Naval Postgraduate School, June 2007.Thesis Advisor(s): Craig Martell, Kevin Squire. "June 2007." Includes bibliographical references (p. 39-40). Also available in print.
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Valerius, Andrew J., and Jeremy M. Smeltz. "Sensor failure detection through introspection." Thesis, Monterey, California. Naval Postgraduate School, 2007. http://hdl.handle.net/10945/3518.
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The advancement of robot technology holds many opportunities for military applications. One area of research being done is simultaneous localization and mapping (SLAM). SLAM uses a robot's sensors to generate a map of the area while maintaining its current position within that map. SLAM research is built upon the assumption that all of the sensors are working correctly. Since field conditions are likely to cause erratic sensor function due to damage or inclement weather conditions, this assumption must be addressed. The goal of our research is to discover methods of effectively performing self-diagnostic checks on robots to detect failures and malfunctions in sensors. There has been little work in the area of error detection in sensors, and what little work has been done has limited applications. This thesis will perform a series of experiments using a variety of different error detection techniques. It is our hope that the methods developed will prove to be applicable to a variety of real world systems.
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Jantvik, Tamas. "Sensory integration - success and failure /." Luleå : Luleå university of technology, 2009. http://pure.ltu.se/ws/fbspretrieve/3283467.
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Jia, Huamin. "Data fusion methodologies for multisensor aircraft navigation systems." Thesis, Cranfield University, 2004. http://hdl.handle.net/1826/781.
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The thesis covers data fusion for aircraft navigation systems in distributed sensor
systems. Data fusion methodologies are developed for the design, development,
analysis and simulation of multisensor aircraft navigation systems. The problems of
sensor failure detection and isolation (FDI), distributed data fusion algorithms and
inertial state integrity monitoring in inertial network systems are studied.
Various existing integrated navigation systems and Kalman filter architectures are
reviewed and a new generalised multisensor data fusion model is presented for the
design and development of multisensor navigation systems. Normalised navigation
algorithms are described for data fusion filter design of inertial network systems.
A normalised measurement model of skewed redundant inertial measurement units
(SRIMU) is presented and performance criteria are developed to evaluate optimal
configurations of SRIMUs in terms of the measurement accuracy and FDI capability.
Novel sensor error compensation filters are designed for the correction of SRIMU
measurement errors. Generalised likelihood ratio test (GLRT) methods are improved
to detect various failure modes, including short time and sequential moving-window
GLRT algorithms.
State-identical and state-associated fusion algorithms are developed for two forms of
distributed sensor network systems. In particular, innovative inertial network sensing
models and inertial network fusion algorithms are developed to provide estimates of
inertial vector states and similar node states. Fusion filter-based integrity monitoring
algorithms are also presented to detect network sensor failures and to examine the
consistency of node state estimates in the inertial network system.
The FDI and data fusion algorithms developed in this thesis are tested and their
performance is evaluated using a multisensor software simulation system developed
during this study programme. The moving-window GLRT algorithms for optimal
SRIMU configurations are shown to perform well and are also able to detect jump
and drift failures in an inertial network system. It is concluded that the inertial
network fusion algorithms could be used in a low-cost inertial network system and
are capable of correctly estimating the inertial vector states and the node states.
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Kotari, Ravi Teja. "Node failure detection and data retrieval in wireless sensor networks." Thesis, California State University, Long Beach, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10108190.
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This project presents a method for detecting node failure in a wireless sensor network. The defective node is identified using round-trip delay measurements. Data transfer from the transmitter section to the receiver section is accomplished via the ZigBee protocol. As soon as a node has been identified as defective, the node is removed from the sensor network. Information about the failed node is provided to users with registered mobile device through the Global System for Mobile (GSM) module. The proposed method has been successfully implemented and tested experimentally on a small sensor network using the LPC2148 ARM7 microcontroller.
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Benkherouf, A. "Failure identification methods for detecting leaks in pipelines and sensor faults." Thesis, University of Manchester, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375341.
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Piercy, Neil Philip. "A redundancy approach to sensor failure detection : with application to turbofan engines." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305488.
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Tunstall, Glen Alan. "Dynamic characterisation of the head-media interface in hard disk drives using novel sensor systems." Thesis, University of Plymouth, 2002. http://hdl.handle.net/10026.1/1643.
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Hard disk drives function perfectly satisfactorily when used in a stable environment, but in certain applications they are subjected to shock and vibration. During the work reported in this thesis it has been found that when typical hard disk drives are subjected lo vibration, data transfer failure is found to be significant at frequencies between 440Hz and 700Hz, at an extreme, failing at only Ig of sinusoidal vibration. These failures can largely be attributed to two key components: the suspension arm and the hard disk. At non-critical frequencies of vibration the typical hard disk drive can reliably transfer data whilst subjected to as much as 45g. When transferring data to the drive controller, the drive's operations are controlled and monitored using BIOS commands. Examining the embedded error signals proved that the drive predominantly failed due lo tracking errors. Novel piezo-electric sensors have been developed to measure unobtrusively suspension arm and disk motion, the results from which show the disk to be the most significant failure mechanism, with its First mode of resonance at around 440Hz. The suspension arm movement has been found to be greatest at IkHz. Extensive modelling of the flexure of the disk, clamped and unclamped, has been undertaken using finite element analysis. The theoretical modelling strongly reinforces the empirical results presented in this thesis. If suspension arm movement is not directly coupled with disk movement then a flying height variation is created. This, together with tracking variations, leads to data transfer corruption. This has been found to occur at IkHz and 2kHz. An optical system has been developed and characterised for a novel and inexpensive flying height measurement system using compact disc player technology.
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Mathew, Jose. "Behaviour of NOx sensors at their end of life." Thesis, KTH, Förbränningsmotorteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-282531.
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NOx-sensorn är grundläggande i det moderna efterbehandlingssystemet och dess pålitlighet är avgörande för att kunna leva upp till rådande emissionslagkrav. Livslängden samt sensorns beteende i slutet av denna varierar betydligt. Om en NOx sensor med oberäkneligt beteende inte upptäcks av fordonets styrsystemet kan det orsaka omfattande verkstadsbesök eller i värsta fall brott mot emissionslagkrav. Examensarbetet involverar identifiering av olika sensorfellägen, tidiga tecken till dessa fellägen, förstå och identifiera förhållanden mellan olika sensorparametrar och analysera sensorbeteendet vid sensorlivslängdens slutskede. NOx sensorn är en relativt ny sensor och fordonsindustrin har ännu inte en fullständig förståelse för dess beteende. Litteraturstudien täcker olika fellägena så som fastnat värde, förskjutet värde, förstärkning av värdet, felaktiga svängningar samt långsam respons. Även effekterna av åldrande i NOx sensorn beskrivs. Litteraturstudien diskuterar också diagnoser av sensorer i allmänhet samt diagnoser specifikt för NOx sensorer. Uppsatsarbetet involverar också en experimentell studie där NOx sensorer utsätts för statiska och fluktuerande gasflöden i en motortestbädd. Fellägen i NOx sensorer kan observeras i parametrarna för NOx-värde och oxidationsnivå. I den version av NOx sensorn som användes observerades det också att parametrarna felaktig NOx och felaktig O2 visar samma felkod samtidigt. Dock är inte parametrarna för felaktig NOx och felaktig O2 relaterade till parametrarna för värmningsstatus, felaktig värmare och värmeelementets temperatur. Sensorns status gällande ogiltiga NOx-mätningar är större än eller lika med antalet ogiltiga O2-mätningar. Resultatet gäller framför allt sensormodell Continental 2.8 NOx sensorer. Även logik för en monitor gällande felaktiga svängningar utvecklas baserat på standardavvikelse och NOx statusparametern för ogiltig mätning.The NOx sensor is essential in the modern after-treatment system and the reliability of the sensor is crucial for any emission-based legislation. The life span of a sensor varies a lot as well as the behaviour previous to its end of life. If a NOx sensor with erratic behaviour is not discovered by the control system it may cause extensive workshop effort or in worst case exceed legal requirements. The thesis work involves identifying different sensor failure modes, precursors to these failure modes, understanding and identifying relationships between different sensor parameters, and analysing the sensor behaviour especially towards the end of life. The NOx sensor is a relatively new sensor and the vehicle industry does not yet have a complete understanding of its behaviour. The literature study covers the different failure modes namely stuck, offset, gain, oscillations, and slow response and their causes along with the effects of ageing in NOx sensors. It also discusses the diagnosis of faulty sensors in general and faulty NOx sensors. The thesis work also involves an experimental study where the NOx sensors are subjected to static and transient gas flow tests in an engine testbed. Failure modes in NOx sensors are observable in NOx concentration and actual oxidation measurement parameters. It was also observed in the version of the NOx sensor used that Error NOx and Error O2 parameters show the same fault code at the same time. Although, the Error NOx and Error O2 parameters are not related to the heater parameters, Heater status, Error heater, and Temperature of heating element. The number of invalid flags set in NOx status is greater than or equal to the number of invalid flags in O2 status. The mentioned parameters are concerning Continental 2.8 NOx sensors. The logic for the oscillatory fault monitor is developed based on standard deviation and an invalid flag check on the NOx status parameter.
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Maalel, Nourhene. "Reliability in wireless sensor networks." Thesis, Compiègne, 2014. http://www.theses.fr/2014COMP1944/document.
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Vu les perspectives qu'ils offrent, les réseaux de capteur sans fil (RCSF) ont perçu un grand engouement de la part de la communauté de recherche ces dernières années. Les RCSF couvrent une large gamme d'applications variant du contrôle d'environnement, le pistage de cible aux applications de santé. Les RCSFs sont souvent déployés aléatoirement. Ce dispersement des capteurs nécessite que les protocoles de transmission utilisés soient résistants aux conditions environnementales (fortes chaleurs ou pluies par exemple) et aux limitations de ressources des nœuds capteurs. En effet, la perte de plusieurs nœuds capteurs peut engendrer la perte de communication entre les différentes entités. Ces limitations peuvent causer la perte des paquets transmis ce qui entrave l'activité du réseau. Par conséquent, il est important d'assurer la fiabilité des transmissions de données dans les RCSF d'autant plus pour les applications critiques comme la détection d'incendies. Dans cette thèse, nous proposons une solution complète de transmission de données dans les RCSF répondant aux exigences et contraintes de ce type de réseau. Dans un premier temps, nous étudions les contraintes et les challenges liés à la fiabilisation des transmissions dans les RCSFs et nous examinons les travaux proposés dans la littérature. Suite à cette étude nous proposons COMN2, une approche distribuée et scalable permettant de faire face à la défaillance des nœuds. Ensuite, nous proposons un mécanisme de contrôle d'erreur minimisant la perte de paquets et proposant un routage adaptatif en fonction de la qualité du lien. Cette solution est basée sur des acquittements implicites (overhearing) pour la détection des pertes des paquets. Nous proposons ensuite ARRP une variante de AJIA combinant les avantages des retransmissions, de la collaboration des nœuds et des FEC. Enfin, nous simulons ces différentes solutions et vérifions leurs performances par rapport à leurs concurrents de l'état de l'artOver the past decades, we have witnessed a proliferation of potential application domainsfor wireless sensor networks (WSN). A comprehensive number of new services such asenvironment monitoring, target tracking, military surveillance and healthcare applicationshave arisen. These networked sensors are usually deployed randomly and left unattendedto perform their mission properly and efficiently. Meanwhile, sensors have to operate ina constrained environment with functional and operational challenges mainly related toresource limitations (energy supply, scarce computational abilities...) and to the noisyreal world of deployment. This harsh environment can cause packet loss or node failurewhich hamper the network activity. Thus, continuous delivery of data requires reliabledata transmission and adaptability to the dynamic environment. Ensuring network reliabilityis consequently a key concern in WSNs and it is even more important in emergencyapplication such disaster management application where reliable data delivery is the keysuccess factor. The main objective of this thesis is to design a reliable end to end solution for data transmission fulfilling the requirements of the constrained WSNs. We tackle two design issues namely recovery from node failure and packet losses and propose solutions to enhance the network reliability. We start by studying WSNs features with a focus on technical challenges and techniques of reliability in order to identify the open issues. Based on this study, we propose a scalable and distributed approach for network recovery from nodefailures in WSNs called CoMN2. Then, we present a lightweight mechanism for packetloss recovery and route quality awareness in WSNs called AJIA. This protocol exploitsthe overhearing feature characterizing the wireless channels as an implicit acknowledgment(ACK) mechanism. In addition, the protocol allows for an adaptive selection of therouting path by achieving required retransmissions on the most reliable link. We provethat AJIA outperforms its competitor AODV in term of delivery ratio in different channelconditions. Thereafter, we present ARRP, a variant of AJIA, combining the strengthsof retransmissions, node collaboration and Forward Error Correction (FEC) in order toprovide a reliable packet loss recovery scheme. We verify the efficiency of ARRP throughextensive simulations which proved its high reliability in comparison to its competitor
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Garrett, Ryan Charles. "Sensor Network for In-Situ Failure Identification in Woven Composites after Impact Events." NCSU, 2007. http://www.lib.ncsu.edu/theses/available/etd-03262007-144306/.
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This study investigates the development of a fiber Bragg grating (FBG) optical sensor network to measure and monitor damage in a composite material induced by low velocity impact events occurring at a single location. The effects of the embedded optical fibers on the host material and their interaction with each other are first considered on both a micro- and macro-mechanics scale. The mechanical low-velocity impact response of two-dimensional woven composite laminates with and without various densities of embedded optical fibers is therefore investigated. Modifications to the specimen fabrication process are then developed to facilitate the embedment of a large density of optical fibers. The light transmission capabilities of embedded optical fibers are also studied to demonstrate that the current fabrication processes permits sufficient light transmission to allow interrogation of the embedded FBG sensor network. The FBG sensor network is finally embedded in a woven composite sample which is then subjected to multiple low velocity impacts events until complete failure of the material system. The FBG sensor data is collected after each impact event, providing a map of the internal strain field in the composite through the progression of damage until failure of the laminate.
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Ullah, Muhammad, and Waqar Ahmad. "Evaluation of Routing Protocols in Wireless Sensor Networks." Thesis, Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-2500.
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The evolution of wireless communication and circuit technology has enabled the development of an infrastructure consists of sensing, computation and communication units that makes administrator capable to observe and react to a phenomena in a particular environment. The building block of such an infrastructure is comprised of hundreds or thousands of small, low cost, multifunctional devices which have the ability to sense compute and communicate using short range transceivers known as sensor nodes. The interconnection of these nodes forming a network called wireless sensor network (WSN). The low cost, ease of deployment, ad hoc and multifunctional nature has exposed WSNs an attractive choice for numerous applications. The application domain of WSNs varies from environmental monitoring, to health care applications, to military operation, to transportation, to security applications, to weather forecasting, to real time tracking, to fire detection and so on. By considering its application areas WSN can be argue as a traditional wired or wireless network. But in reality, these networks are comprised of battery operated tiny nodes with limitations in their computation capabilities, memory, bandwidth, and hardware resulting in resource constrained WSN. The resource constrained nature of WSN impels various challenges in its design and operations degrading its performance. On the other hand, varying numbers of applications having different constraints in their nature makes it further challenging for such resources constrained networks to attain application expectations. These challenges can be seen at different layer of WSNs starting from physical layer up to application layer. At routing layer, routing protocols are mainly concerned with WSN operation. The presence of these challenges affects the performance of routing protocols resulting in overall WSN performance degradation. The aim of this study is to identify the performance challenges of WSN and analyze their impact on the performance of routing protocols. For this purpose a thorough literature study is performed to identify the issues affecting the routing protocols performance. Then to validate the impact of identified challenges from literature, an empirical study has been conducted by simulating different routing protocols, taking into consideration these challenges and results are shown. On the basis of achieved results from empirical study and literature review recommendations are made for better selection of protocol regarding to application nature in the presence of considered challenges.
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Ainchwar, Arpit. "Determination of Cycle Time Constraints in Case of Link Failure in Closed Loop Control in Internet of Things." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/36906.
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In today’s era of the Internet of Things, it is crucial to study the real-time dependencies of the web, its failures and time delays. Today, smart grids, sensible homes, wise water networks, intelligent transportation, infrastructure systems that connect our world over are developing fast. The shared vision of such systems is typically associated with one single conception Internet of Things (IoT), where through the deployment of sensors, the entire physical infrastructure is firmly fastened with information and communication technologies; where intelligent observation and management is achieved via the usage of networked embedded devices.
The performance of a real-time control depends not only on the reliability of the hardware and software used but also on the time delay in estimating the output, because of the effects of computing time delay on the control system performance. For a given fixed sampling interval, the delay and loss issues are the consequences of computing time delay. The delay problem occurs when the computing time delay is non-zero but smaller than the sampling interval, while the loss problem occurs when the computing time delay is greater than, or equal to, the sampling interval, i.e., loss of the control output. These two queries are analyzed as a means of evaluating real-time control systems. First, a general analysis of the effects of computing time delay is presented along with necessary conditions for system stability. In this thesis, we will focus on the experimental study of the closed loop control system in the internet of things to determine the cycle time constraints in case of link failure.
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Martin, Anthony Russell. "Impact damage detection in filament wound tubes using embedded optical fibre sensors." Thesis, Brunel University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266542.
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Hu, Kai. "Solving Inverse Problems Using Particle Swarm Optimization: An Application to Aircraft Fuel Measurement Considering Sensor Failure." Cincinnati, Ohio : University of Cincinnati, 2006. http://www.ohiolink.edu/etd/view.cgi?acc%5Fnum=ucin1141398269.
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Thesis (M.S.)--University of Cincinnati, 2006.Title from electronic thesis title page (viewed Apr. 19, 2006). Includes abstract. Keywords: Inverse Problem, Particle Swarm Optimization, Neural Networks, Aircraft Fuel Measurement, Sensor Failure Includes bibliographical references.
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Lesho, Jeffrey Carl. "Embedded damage sensor using triboluminescence as a transduction mechanism for detecting failure of a material under load." Available to US Hopkins community, 2002. http://wwwlib.umi.com/dissertations/dlnow/3068181.
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Pahome, Thanadon, and Narat Amorntatkul. "How sensory marketing applies to the hotel and restaurant industry in order to influence customer’s behaviour in Thailand." Thesis, Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-12634.
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Monteuuis, Jean-Philippe. "Resilience by design & failures forecasting for a connected autonomous vehicle." Thesis, Institut polytechnique de Paris, 2020. http://www.theses.fr/2020IPPAT003.
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Les véhicules autonomes dotés d'un niveau d'automatisation 5 conduiront de manière autonome dans tous les scénarios routiers tels que les autoroutes, les routes enneigées, les zones urbaines ou les embouteillages. L'intégration de la communication V2X, en tant que nouvelle source de perception du véhicule, pourrait supprimer les limitations de la perception locale en communiquant avec un piéton caché par un obstacle ou en détectant à l'avance la présence d'un véhicule caché par un brouillard épais. Cependant, cette communication V2X peut constituer une nouvelle source d'attaques menaçant la perception du véhicule. Les contre-mesures actuelles ne sont pas conçues pour toutes les architectures de véhicules autonomes, car elles requièrent l'assistance du conducteur ou fonctionnent avec un ensemble spécifique de capteurs. La thèse vise donc à proposer une architecture de perception générique et résiliante aux défaillances pour tous les types de véhicules connectés et autonomes. Dans cette thèse, nous proposons une architecture de perception générique nommée GPA avec son algorithme de perception résiliante aux défaillances (FRPA). Nous proposons une nouvelle méthode d'analyse de menaces et d'évaluation des risques nommée SARA, qui identifie et évalue le risque d'attaques ciblant les véhicules connectés et automatisés de niveau 5. Pour identifier où et comment ces attaques ont lieu, nous proposons un modèle d'attaquant et un modèle d'objectifs de sécurité pour tous les systèmes de perception automobile. Nous avons implémenté deux modules de notre algorithme FRPA: un module classification des défaillances basé sur une méthode de Machine Learning et un module de corrélation V2X-Capteur en considérant trois sources d'information: radar, camera et V2X. Nous avons mis en évidence plusieurs nouvelles attaques dans le cycle de perception et soulevé le besoin de nouvelles contre-mesures de sécurité centrées sur l'intégrité physique des infrastructures routières et sur les algorithmes de perception fiables. De plus, nos contre-mesures basées sur l'apprentissage automatique et la corrélation entre capteurs sont très précises pour détecter et classifier les défaillances de perception (score de précision supérieur à 90 %). Enfin, les idées développées dans la thèse ont abouti à 10 brevets déposés et à plusieurs publicationsAutonomous vehicles with an automation level 5 will drive autonomously in any road scenarios such as highways, snowy roads, urban areas, or traffic jams. The integration of V2X communication, as a new source of perception for the vehicle could remove the limitations of local perception by communicating with an occluded pedestrian or by detecting in advance the presence of a vehicle under a heavy mist. However, this V2X communication may be a new source of attacks threatening the vehicle perception. Current countermeasures are not designed for all autonomous vehicles because these countermeasures require the driver assistance or work with a specific set of sensors. Therefore, the thesis aims to propose a generic failure resilient perception architecture for all types of connected and autonomous vehicles supporting different kinds of sensors. In this thesis, we propose a generic perception architecture named GPA with its failure resilient perception algorithm (FRPA). We propose a new threat analysis and risk assessment method named SARA that identifies and assess the risk of attacks targeting connected and automated vehicles with an automation level 5. To identify where and how these attacks occur, we propose an attacker and a security goal model for all automotive perception systems. We implemented two modules of our failures resilient perception algorithm (FRPA): a Machine Learning based Failure Classifier and a V2X-Sensor Correlation Module considering three kinds of source: camera, radar, and V2X. We highlighted several new attacks in the perception pipeline and raise the need for new security countermeasures such as the physical integrity of road infrastructures and trustworthy perception algorithms. Besides, our countermeasures based on machine learning and sensor correlation showed very accurate results to detect and classifies perception failures (over 90% accuracy score). Finally, the ideas developed in the thesis resulted in 10 filled patents and several publications
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Nolan, Melissa A. "Microfabricated iridium arrays : failure mechanisms, investigation of the Hg-Ir interface and their use in Cu or Hg determination /." Thesis, Connect to Dissertations & Theses @ Tufts University, 1999.
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Thesis (Ph.D.)--Tufts University, 1999.Adviser: Samuel P. Kaunaves. Submitted to the Dept. of Chemistry. Includes bibliographical references (leaves 190). Access restricted to members of the Tufts University community. Also available via the World Wide Web;
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Skuba, Andrew. "In vivo imaging analysis of the regeneration failure of dorsal root axons in adult mice." Diss., Temple University Libraries, 2014. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/292900.
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Cell BiologyPh.D.
After injury, dorsal root (DR) axons regenerate in the peripheral nervous system (PNS), but turn around or stop at the dorsal root entry zone (DREZ), the entrance into the central nervous system (CNS). Examination of the dynamic axon regeneration that occurs following injury to the DR provides the opportunity to advance our understanding of what happens to sensory axons as they approach and arrive at the DREZ and expands our knowledge of sensory axon regeneration failure at the entrance to the spinal cord. Additionally, findings from these studies may offer potential avenues to provide insight into regeneration failure elsewhere in the central nervous system. Nevertheless, our understanding of the cellular and molecular processes underlying the failure of DR axons to regenerate through the DREZ is incomplete. The goal of my thesis work was to determine whether application of the time lapse-in vivo imaging technique is feasible and useful in studying dorsal root regeneration. I have also applied recently developed post-mortem analyses to the axons monitored in vivo, which provided additional insights into the mechanisms that prevent axon regeneration at the DREZ. Results in Chapters 2 and 3 demonstrate that wide-field microscopy is indeed feasible and useful for monitoring regenerating sensory axons immediately before, during, and in the days to weeks after lumbar (L5) DR crush. I was surprised to find that most axons were immobilized abruptly and chronically at the CNS portion of the DREZ, with their axon tips and shafts exhibiting features of differentiated nerve terminals. This observation raises the possibility, which has not been appreciated previously, that DR axons stop at the DREZ because their regeneration is terminated prematurely by forming synaptic contacts with unidentified postsynaptic cells. To confirm the immobilization of DR axons at the DREZ, I applied two-photon microscopy to examine the axon behavior at the DREZ at high resolution. Results described in Chapter 4 confirm those obtained with the time-lapse imaging performed with wide-field microscopy: axons arrested soon after their arrival at the DREZ did not exhibit even subtle movements. Light microscopic analyses of the failed axon tips monitored in vivo demonstrated that almost all axons stopped at the CNS territory of the DREZ, and that axon tips and adjacent shafts intensely immunolabeled with synapse markers. Ultrastructural analyses revealed that numerous axonal profiles had the characteristic features of pre- but not postsynaptic endings. Findings from these studies lead us to speculate that most, if not all, dorsal root axons become arrested as they enter the CNS territory of the DREZ by forming presynaptic terminals on non-neuronal cellular elements that differ from the dystrophic-like endings formed by a few axons. In the chapter 5, I discuss what I have found to be the key factors for successful monitoring of regenerating dorsal root axons in living animals; the feasibility, usefulness and limitations of the available techniques and future directions for studying spinal root injury and regeneration. My thesis work represents the first to employ in vivo imaging to study DR regeneration directly in living animals. This approach was more challenging to develop than we had anticipated but provided unexpected insights into the mechanisms preventing sensory nerve regeneration. Continuous application of the powerful in vivo imaging technique in combination with conventional analyses will elucidate critically important issues that previous static analyses could not decipher.
Temple University--Theses
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Wichern, Donald Monte. "A Framework for an Implantable Wireless Pressure and Volume Sensor Focusing on the Diagnosis and Treatment of Shunt Failure in Hydrocephalus Patients." Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1162.pdf.
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Speer, Ngoc Anh Phan. "Design and Analysis of Adaptive Fault Tolerant QoS Control Algorithms for Query Processing in Wireless Sensor Networks." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/27221.
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Data sensing and retrieval in WSNs have a great applicability in military, environmental, medical, home and commercial applications. In query-based WSNs, a user would issue a query with QoS requirements in terms of reliability and timeliness, and expect a correct response to be returned within the deadline. Satisfying these QoS requirements requires that fault tolerance mechanisms through redundancy be used, which may cause the energy of the system to deplete quickly. This dissertation presents the design and validation of adaptive fault tolerant QoS control algorithms with the objective to achieve the desired quality of service (QoS) requirements and maximize the system lifetime in query-based WSNs. We analyze the effect of redundancy on the mean time to failure (MTTF) of query-based cluster-structured WSNs and show that an optimal redundancy level exists such that the MTTF of the system is maximized.
We develop a hop-by-hop data delivery (HHDD) mechanism and an Adaptive Fault Tolerant Quality of Service Control (AFTQC) algorithm in which we utilize "source" and "path" redundancy with the goal to satisfy application QoS requirements while maximizing the lifetime of WSNs. To deal with network dynamics, we investigate proactive and reactive methods to dynamically collect channel and delay conditions to determine the optimal redundancy level at runtime. AFTQC can adapt to network dynamics that cause changes to the node density, residual energy, sensor failure probability, and radio range due to energy consumption, node failures, and change of node connectivity. Further, AFTQC can deal with software faults, concurrent query processing with distinct QoS requirements, and data aggregation. We compare our design with a baseline design without redundancy based on acknowledgement for data transmission and geographical routing for relaying packets to demonstrate the feasibility. We validate analytical results with extensive simulation studies. When given QoS requirements of queries in terms of reliability and timeliness, our AFTQC design allows optimal â sourceâ and â pathâ redundancies to be identified and applied dynamically in response to network dynamics such that not only query QoS requirements are satisfied, as long as adequate resources are available, but also the lifetime of the system is prolonged.Ph. D.
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Bowersox, Linda. "Implementation of a Heart Failure Self-care to Success Program in Underserved Community Dwelling Seniors." Thesis, The William Paterson University of New Jersey, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10933709.
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The purpose of this partial replication study was to explore the effectiveness of APRN driven educational interventions implemented through the Heart Failure Self Care to Success (HF S2S) program, for underserved urban seniors in four senior housing buildings. The effectiveness of the HF S2S program on pre and post scores on the SCHFI v 6.2 tool was measured to determine if scores improved post educational intervention.
A mixed methods approach was utilized with the qualitative component using a paired samples t test. For the qualitative aspect, a focus group of eight participants was added to gain a better understanding of the barriers in HF self-care.
There were differences in mean scores for pre versus post test on the SCHFI Tool, for Section A, Self-Care Maintenance and Section C, Self-care confidence with the post-test scores being higher by 18.98 and 22.15 points, respectively. Those differences were statistically significant at the p<.05, indicating a strong and significant impact from the HFS2S Program. There was no statistically significant difference between pre and post test scores following educational intervention in Section B, Self-Care Management, p>.05.
For the qualitative component of the research, a total of 64 responses were generated from a focus group of eight. The vast majority of the group felt that their biggest barrier was self-care adherence as it relates to their HF. Cost of medication, lack of transportation, decreased mobility, ineffective access to care and the inability to locally purchase healthy foods were prominent obstacles. The findings of this APRN led initiative demonstrates that APRN educational interventions on HF were effective in improving self-care maintenance and self-care confidence.
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Megahed, Mohamed Helmy Mostafa. "SurvSec Security Architecture for Reliable Surveillance WSN Recovery from Base Station Failure." Thèse, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/31154.
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Surveillance wireless sensor networks (WSNs) are highly vulnerable to the failure of the base station (BS) because attackers can easily render the network useless for relatively long periods of time by only destroying the BS. The time and effort needed to destroy the BS is much less than that needed to destroy the numerous sensing nodes.
Previous works have tackled BS failure by deploying a mobile BS or by using multiple BSs, which requires extra cost. Moreover, despite using the best electronic countermeasures, intrusion tolerance systems and anti-traffic analysis strategies to protect the BSs, an adversary can still destroy them. The new BS cannot trust the deployed sensor nodes. Also, previous works lack both the procedures to ensure network reliability and security during BS failure such as storing then sending reports concerning security threats against nodes to the new BS and the procedures to verify the trustworthiness of the deployed sensing nodes. Otherwise, a new WSN must be re-deployed which involves a high cost and requires time for the deployment and setup of the new WSN. In this thesis, we address the problem of reliable recovery from a BS failure by proposing a new security architecture called Surveillance Security (SurvSec).
SurvSec continuously monitors the network for security threats and stores data related to node security, detects and authenticates the new BS, and recovers the stored data at the new BS. SurvSec includes encryption for security-related information using an efficient dynamic secret sharing algorithm, where previous work has high computations for dynamic secret sharing. SurvSec includes compromised nodes detection protocol against collaborative work of attackers working at the same time where previous works have been inefficient against collaborative work of attackers working at the same time.
SurvSec includes a key management scheme for homogenous WSN, where previous works assume heterogeneous WSN using High-end Sensor Nodes (HSN) which are the best target for the attackers. SurvSec includes efficient encryption architecture against quantum computers with a low time delay for encryption and decryption, where previous works have had high time delay to encrypt and decrypt large data size, where AES-256 has 14 rounds and high delay. SurvSec consists of five components, which are:
1. A Hierarchical Data Storage and Data Recovery System.
2. Security for the Stored Data using a new dynamic secret sharing algorithm.
3. A Compromised-Nodes Detection Algorithm at the first stage.
4. A Hybrid and Dynamic Key Management scheme for homogenous network.
5. Powerful Encryption Architecture for post-quantum computers with low time delay.
In this thesis, we introduce six new contributions which are the followings:
1. The development of the new security architecture called Surveillance Security (SurvSec) based on distributed Security Managers (SMs) to enable distributed network security and distributed secure storage.
2. The design of a new dynamic secret sharing algorithm to secure the stored data by using distributed users tables.
3. A new algorithm to detect compromised nodes at the first stage, when a group of attackers capture many legitimate nodes after the base station destruction. This algorithm is designed to be resistant against a group of attackers working at the same time to compromise many legitimate nodes during the base station failure.
4. A hybrid and dynamic key management scheme for homogenous network which is called certificates shared verification key management.
5. A new encryption architecture which is called the spread spectrum encryption architecture SSEA to resist quantum-computers attacks.
6. Hardware implementation of reliable network recovery from BS failure.
The description of the new security architecture SurvSec components is done followed by a simulation and analytical study of the proposed solutions to show its performance.
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Šimoník, Martin. "Funkční bezpečnost snímačů tlaku BD SENSORS, s.r.o." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2015. http://www.nusl.cz/ntk/nusl-221099.
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This master thesis examines the functional safety of the pressure sensor XMP i which is produced by BD SENSORS Company. The aim of this thesis is the demonstration of compliance of the pressure sensor XMP I with functional safety integrity level SIL3 requirements. The thesis is divided into three parts. The first part deals with the concept of functional safety, defines the basic concepts of functional safety, compares the approaches of functional safety according to selected standards and provides a general procedure for the functional safety determination. The second part deal with technical systems reliability defines reliability indicators and describes selected types of reliability analysis used in practice, especially the FMEA/FMECA analysis. Third part deals with the reliability analysis of the sensor XMP i and with evaluation of results.
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Conradie, Nelene. "The development and testing of recipes for patients with chronic renal failure." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/4060.
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Thesis (MNutr (Human Nutrition))--University of Stellenbosch, 2009.ENGLISH ABSTRACT: Background Patients with chronic renal failure must deal not only with the disease itself, but also have to follow a strict dietary regimen. In South Africa there is currently a great demand for new and updated recipes based on the South African Renal Exchange Lists. The focus of this research was the development and testing of recipes commonly used by renal patients following a westernised diet. Objectives The main objectives of the study were to develop and test recipes that meet the nutritional requirements of patients with chronic renal failure. The secondary objectives were to determine the gender and racial differences in participants’ responses during consumer sensory testing. Methodology The study population consisted of patients with chronic renal failure on hemodialysis and continuous ambulatory peritoneal dialysis from Tygerberg Academic Hospital (TAH). Data was collected in three phases, using census sampling: Phase 1 included the development and adaptation of recipes to suit the renal diet. Phase 2 included the consumer sensory testing of the recipes by the dialysis patients, using the 9-point hedonic scale. Phase 3 included the rating of the recipes, the final nutritional analysis and allocation of renal exchanges to one portion of each recipe, as well as the final formatting of the recipe to make it more user-friendly for the renal patient. Results In total, 45 patients took part in the sensory evaluation of 30 recipes. Eighty percent of the subjects were coloured, 4% were white while 16% were black. Fifty-one percent (n=23) were female and 49% (n=22) were male. Of the 30 recipes that were evaluated for overall acceptance, appearance, smell, texture and taste, only 7 were deemed unacceptable. Recipes were unacceptable when less than 80% of the study participants gave a mean overall score of more than 6. Significant differences in the overall acceptability scores were found between the male and female subgroups for the Fish and Vegetable Pie (p=0.031), Chicken Pilaf (p=0.008) and Date Fingers (p=0.002). The females showed a greater preference for these two main meals while the males showed a greater preference for the Date Fingers. Significant differences were found between the black and westernised subgroups for the Rice Salad (p=0.006), Wheat and Mushroom Casserole (p=0.022), Curried Wheat Salad (p=0.043) and the Coconut Ice (p=0.005), with the westernised subgroup showing a greater preference for the dishes than the black subgroup. Conclusion The 23 recipes that were acceptable to the study participants are recommended for inclusion in the RenalSmart Software programme. These recipes are suitable for patients following a westernised diet. It is proposed that recipes suitable for the black and Indian population must be developed in future research.
AFRIKAANSE OPSOMMING: Agtergrond Pasiënte met chroniese nierversaking moet nie net slegs die siektetoestand hanteer nie, maar moet ook ‘n streng dieet regime volg. Daar is huidiglik in Suid-Afrika ‘n groot behoefte vir nuwe en opgedateerde resepte gebasseer op die Suid-Afrikaanse Nier Ruillyste. Die fokus van hierdie navorsing was om resepte te ontwikkel en te toets wat algemeen ingeneem word deur nierversaking pasiënte wat ‘n westerse dieet volg. Doelwitte Die hoof doelwitte van die studie was om resepte te identifiseer en te toets wat voldoen aan die nutrisionele behoeftes van nierpasiënte met kroniese nierversaking. Die sekondêre doelwitte was om geslag en ras verskille in die deelnemers se reaksies tydens verbruiker sensoriese evaluering te bepaal. Metodologie Die studie populasie het bestaan uit pasiënte met chroniese nierversaking op hemodialise en aaneenlopende ambulatoriese peritoneale dialise van Tygerberg Akademiese Hospitaal (TAH). Data was versamel in drie fases deur gebruik te maak van sensus steekproeftrekking: Fase 1 het die ontwikkeling en aanpassings van die resepte, om dit toepaslik te maak vir die nier dieet, ingesluit. Fase 2 het die verbruiker sensoriese evaluering van die resepte deur die dialise pasiënte, met behulp van die 9-punt hedoniese skaal, ingesluit. Fase 3 het die klassifisering van die resepte, die finale nutrisionele analise en die toekenning van nier ruile per porsie van elke resep, sowel as die finale formatering om die resep meer gebruikersvriendelik te maak vir die nierpasiënt, ingesluit. Resultate In totaal het 45 pasiënte aan die sensoriese evaluering van die 30 resepte deelgeneem. Tagtig persent van die deelnemers was kleurling, 4% was wit en 16% was swart. Een en vyftig persent (n=23) was vroulik en 49% (n=22) was manlik. Van die 30 resepte wat geevalueer is vir algehele aanvaarding, voorkoms, reuk, tekstuur en smaak, was slegs 7 onaanvaarbaar gevind. Resepte is as onaanvaarbaar beskou indien minder as 80% van die deelnemers ‘n gemiddelde algehele telling van meer as 6 gegee het. Beduidende verskille in die algehele aanvaarbaarheid tellings is gevind tussen die mans en vroue vir die Vis en Groente Pastei (p=0.031), Hoender Pilaf (p=0.008) en Dadelvingers (p=0.002). Die vrouens het ‘n groter voorkeur vir die twee hoofgeregte getoon terwyl die mans ‘n groter voorkeur vir die Dadelvingers getoon het. Beduidende verskille is gevind tussen die swart en westerse sub-groepe vir die Rysslaai (p=0.006), Koring en Sampioen Kasserol (o=0.022), Kerrie Koringslaai (p=0.043) en die Klapperys (p=0.005), met die westerse sub-groep wat ‘n groter voorkeur vir dié geregte toon as die swartes. Gevolgtrekking Die 23 resepte wat aanvaarbaar gevind is sal voorgestel word om ingesluit te word in die RenalSmart Sagteware program. Die resepte is toepaslik vir pasiënte wat ‘n westerse dieet volg. Daar word voorgestel dat resepte toepaslik vir die swart en Indiër populasie ontwikkel word in toekomstige navorsing.
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Del, Rio Reina. "Quality of Life and Hospital Readmissions among Patients with NYHA Class III Heart Failure Following Implantation of Cardiomems(TM) Sensor| A Mixed Methods Study." Thesis, Sage Graduate School, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10974669.
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Heart failure is a disease with high morbidity and mortality in the U.S. and globally. There are about 5.7 million people in the U.S with heart failure, and about 10 million in Europe. The disease is present more frequently in patients over 65 years old. Data from the ongoing Framingham Heart Study has shown that the one-year mortality rate is 22% and the 5-year mortality rate is 42%. While there have been significant advancements in the care of patients with heart failure, there is still no cure. In addition, Medicare has estimated that the number one cause for hospital admissions in the U.S. is heart failure, according to ICD-9 and ICD-10 reimbursement codes.
The CardioMEMS™ Heart Failure System is the first implantable device in the U.S. that has shown to decrease the number of HF-related hospital readmissions in patients implanted with the sensor and reported in the original CHAMPION trial. This study focused upon the evaluation of HF patients’ perception of quality of life and whether there was a statistically significant decrease in the number of HF-related hospital readmissions among those implanted with the CardioMEMS™ sensor.
This study was conducted in three phases: one qualitative and two quantitative phases. The qualitative aspect included individual interviews with NYHA Class III HF patients who had the CardioMEMS™ sensor implanted.
Qualitative study findings revealed that patients with HF experienced fatigue that impacted their activities of daily living, particularly those involving family. It also revealed that despite the fact that none of the respondents had been hospitalized for a HF-related reason, most did not perceive an improvement in their quality of life since implantation of the CardioMEMS™ sensor based on individual participant interviews.
The first quantitative aspect of the study assessed the perception of quality of life of these same patients based upon individual MLFHQ scores. Findings from MLHFQ results revealed that there was a negative impact in respondents’ quality of life, particularly in the physical dimensions of the MLHFQ. Interestingly, those scores were somewhat lower than what is found in the literature.
The second of the quantitative phase analyzed the number of HF-related hospital admissions in patients with the CardioMEMS™ sensor based on a 1:28 retrospective case-control matching study design. Analysis showed that patients implanted with the CardioMEMS™ sensor had a statistically significant decrease in the number of HF-related hospital admissions. Incidental findings also showed a statistically significant decrease in the number of HF-related hospital readmissions in patients with NYHA Class III HF after implantation of the CardioMEMS™. This is compelling evidence of the need for further studies in this new technology and its impact on patients with NYHA Class III HF.
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Moretto, Simone Alvarez. "Análise da correlação existente entre Senso de Coerência e adesão ao tratamento em pacientes com diagnóstico de insuficiência cardíaca crônica." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/7/7139/tde-20092013-085831/.
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Introdução: a insuficiência cardíaca (IC) caracteriza-se por uma síndrome complexa, que apresenta, como principais sintomas, falta de ar, fadiga e função cardíaca anormal, o que exige, dos pacientes, mudanças no estilo de vida. Observa-se que as orientações de cuidado, muitas vezes, não são incorporados pelo portador de IC, sendo este um importante aspecto para a piora clínica deste paciente. Na perspectiva do enfrentamento, o Senso de Coerência proposto por Aaron Antonovsky, referencial adotado nesta pesquisa, é um construto que, se bem aplicado aos portadores de IC, pode revelar aos profissionais de saúde a percepção que os pacientes apresentam acerca de sua condição de doença. Objetivo: analisar a existência de correlação entre a adesão ao tratamento e o senso de coerência em pacientes ambulatoriais com diagnóstico de IC. Material e Método: estudo exploratório, descritivo, prospectivo e de abordagem quantitativa, realizado no ambulatório especializado em Insuficiência Cardíaca e Transplante do Instituto do Coração do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, com amostra de 100 pacientes. Os instrumentos utilizados na análise foram o Questionário de Senso de Coerência e o Questionário de Adesão em Pacientes com Insuficiência Cardíaca, além de um roteiro de entrevista semiestruturada para a caracterização da amostra da população de estudo. Os dados clínicos foram coletados do prontuário eletrônico dos pacientes. A regressão linear múltipla foi a estratégia utilizada para identificação dos fatores associados à adesão e ao senso de coerência, enquanto o nível de significância utilizado foi 5%. Resultados: o perfil biossocial da amostra foi predominantemente de homens (70%), com idade superior a 40 anos (89%), casados ou com companheiros (66%), baixa escolaridade (65% ensino fundamental), vinculados à religião católica (66%), aposentados (44%), com antecedentes clínicos de hipertensão (54%), dislipidemias (31%) e diabetes (25%). O principal diagnóstico responsável pelo quadro de IC foram as miocardiopatias (91%). Com relação ao senso de coerência, a distribuição da pontuação na amostra da população estudada variou entre 79 e 196, com média de 147,99 e desvio padrão de 23,101. A pontuação do questionário podia variar entre 29 e 203 pontos. A pontuação no questionário de adesão variou entre 26 e 58 pontos, média de 43,13, desvio padrão em 8,099. Neste questionário, a pontuação poderia variar entre 0 e 60 pontos. A idade foi o único fator preditor de adesão ao tratamento. Gênero e renda familiar apareceram como fatores preditores do domínio compreensão do senso de coerência. O gênero, isoladamente, foi determinado como fator preditor dos domínios Manuseio, Significado e para o senso de coerência. A correlação entre senso de coerência e adesão ao tratamento não foi significativa. Houve correlação significativa e negativa entre idade e adesão ao tratamento. A miocardiopatia mostrou-se como significativa, quando se refere à adesão ao tratamento. Neste caso, dentre os indivíduos que apresentaram valores menores ou iguais à média para o escore adesão (51%), 43% eram miocardiopatas. A hipertensão arterial sistêmica apresentou-se como variável significativa para o domínio compreensão do construto senso de coerência. Dentre os indivíduos que apresentaram valores menores ou iguais à média, para o escore em questão (51%), 22% eram hipertensos. Conclusões: a análise do Senso de Coerência e sua relação com a adesão ao tratamento em doenças crônicas é, em geral, pouco estudada. Não houve correlação entre Senso de Coerência e adesão ao tratamento, porém o instrumento de adesão não apresentou consistência interna relevante para a análise. Os resultados desta pesquisa poderão ser utilizados para a melhoria da prática assistencial de enfermeiros no cuidado a pacientes com IC.Introduction: heart failure (HF) is characterized by a complex syndrome that has as its main symptoms shortness of breath, fatigue, and abnormal cardiac function. It demands a change of lifestyle in patients, that most of the time, are not adequately adopted, causing problems in treatment Compliance. In the confrontation perspective, the Sense of Coherence proposed by Aaron Antonovsky, used in this research as reference, is a construct that, if well applied to the sufferers of heart failure, it could reveal to the health professional, the perception patients have around their illness. Objective: Analyze the existence of a correlation between compliance to treatment and Sense of Coherence in clinical patients with a diagnosis of heart failure. Materials and Method: This is a exploratory study, descriptive, prospective, of a quantitative approach, which took place in the Heart Failure and Transplant Specialty Clinic at the Instituto do Coração (Heart Institute) of Hospital das Clínicas of the Medical College of the University of São Paulo (InCor-HC FMUSP), with a sample of 100 patients. The means used for analysis were Sense of Coherence and Treatment Compliance Questionnaire, as well as a directed semi-structured interview for the characterization of the sample of the population in the study. The clinical data was collected from the patients electronic medical records. Multiple Linear Regression was the strategy used to identify the factors associated to Treatment Compliance and Sense of Coherence, and the significance level used was 5%. Results: The Biosocial profile of the sample was predominantly of males (70%), over 40 years old (89%), married or with partners (66%), retired (44%), with a history of clinical hypertension (54%), dyslipidemia (31%) and diabetes (25%). The primary diagnosis responsible for the Heart Failure Clinical profile was Cardiomyopathy (91%). As for the Sense of Coherence, the distribution of scoring points in the sample of the population studied varied between 79 and 196, with an average of 147, 99 and standard deviation of 23.101. The scoring in the Questionnaire can vary between 29 and 203 points. The scoring in the Treatment Compliance Questionnaire varied between 26 and 58 points, average of 43,13 and Standard Deviation in 8.099. In this questionnaire the scoring can vary between 0 and 60 points. Age was the only predictor in Treatment Compliance. Gender and family income appear as predicting factors in the domain of Sense of Coherence comprehension. Isolated, gender was a determinant as a predicting factor in the domains of handling, Significance and Sense of Coherence. The correlation between Sense of Coherence and Compliance of Treatment wasnt significant. There was a significant and negative correlation between age and Treatment Compliance. Cardiomyopathy appeared as significant when dealing with Treatment Compliance. In this case, among the individuals that showed lower or equal values to the average score of Treatment Compliance (51%), 43% had Cardiomyopathy. Systemic Arterial Hypertension, appeared as a significant variable for the domain of Comprehension of the Sense of Coherence Construct. Among the individuals that showed lower or equal to the average score in question values (51%), 22% were hypertensive. Conclusion: The Analysis of the Sense of Coherence in relation to Treatment Compliance in chronic diseases is in general, not very well researched. There was no correlation between Sense of Coherence and Treatment Compliance, although the Treatment Compliance instrument did not present internal consistence relevant to the analysis. The conclusions of this research can be employed in the improvement of clinical practice of nurses in the caring of patients with Heart Failure.
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Beech, J. G. "An investigation into the notions of 'success' and 'failure' held by senior UK airline executives and their perceptions of the causes of 'success'." Thesis, Cranfield University, 2003. http://hdl.handle.net/1826/112.
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This study explores the notions of 'success' and 'failure' held by senior executives in the UK and Irish airline industry. Previous studies of this industry have tended to be from a positivist perspective, focusing on financial performance at the level of 'airline' or 'airline industry'. This study takes the airline executive as the unit of analysis and is conducted from a phenomenological perspective.
A methodology using interviews, causal mapping and postal questionnaires is applied to surface the notions of 'success' and 'failure' and the perception of the causes of 'success' held by board-level airline executives. Standardised data published by the Civil Aviation Authority Economic Research Group is used to establish a range of objective measures, both financial and operational, and these objective measures are compared with the rankings of the senior executives' perceptions of the success of UK and Irish airlines.
The research establishes that senior airline executives do not see 'success' in terms of financial objective measures such as Added Value or Operating Ratio; they use profit as the primary financial measure of 'success' and frequently hold notions of 'success' that are based in other functional areas such as operations and marketing. The causes of 'success' are seen as coming from the breadth of functional areas. The influence of HRM factors becomes clearer at deeper levels of abstraction when considering 'success'. There is limited evidence of the stereotyping of perceptions when the success of specific airlines is considered, but not for airlines' success in general.
Recommendations for further research into the management of human resources within airlines are made.
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Bongela, Knobel Sakhiwo. "An investigation into the causes of the high failure rate in std. 10 Xhosa in the Transkei Senior Secondary Schools between 1981 and 1985." University of the Western Cape, 1992. http://hdl.handle.net/11394/8200.
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Magister Educationis - MEdThis study1 which followed immediately after a sub-dissertation entitled "An investigation into the problems and pitfalls inherent in the teaching and learning of Xhosa in the .Senior Secondary schools of Transkei" and which was part of the re~earcher's Bachelor of Education academic study programme, was designed to probe deeper into the problems discoverd earlier in the study mentioned above, and to further investigate the root causes of the high rate of failure in Xhosa which has become a source of worry to the Transkei Education Department today. To gather all the data needed during investigation, use of questions and intervi•ews was made. Questionnaires were sent to Std 10 pupils, Std 10 teachers, Std 10 External Examiners and libraries. Files of the Xhosa Subject Commit.tee, the Xhosa Action Committee, the Nguni and Sesotho Language Board and the Transkei Examinations Board were consulted with a view to extracting information that would reveal records pertaining to high failure rate in Xhosa. After observing for several years, as a teacher and examiner of Xhosa language, the performance of Std 10 pupils writing Xhosa, the researcher came tot.he conclusion that there was indeed high failure rate in Xhosa. The period 1981 to 1985 became the focus of his attention because it was the worst in the history of the Transkei Std 10 results in Xhosa. Records of the Transkei Examinations Board reflected that the mean average during that period was only 46'l. (See· Table 1.1). The poor results also became the source of worry to the Department of Education which took steps to remedy the situation by forming a special Committee known as the Xhosa Action Committee which was given the task of devising ways and means of improving the Std 10 Xhosa results as from 1985. The Department further sent out circulars to all schools in Transkei threatening to take disciplinary measures against Std 10 Xhosa teachers whose candidates had failed to .secure less than 50% aggregate in the external examinations.
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Hamadi, Hussein. "Fault-tolerant control of a multirotor unmanned aerial vehicle under hardware and software failures." Thesis, Compiègne, 2020. http://www.theses.fr/2020COMP2555.
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Le but de ce travail est de proposer des mécanismes pour les drones multirotors qui permettent d'une part de tolérer des fautes sur le drone, et d'autre part de prendre en compte les effets du vent en extérieur. Les fautes visées comportent des fautes d'actionneurs, de capteurs, mais également des fautes logicielles sur les algorithmes de fusion de données. Dans nos travaux, nous avons développé un contrôleur robuste et un observateur des perturbations extérieures capables de coopérer avec la méthode de reconfiguration des commandes, pour tolérer de façon simultanée les défaillances de moteurs et les perturbations extérieures du vent par des techniques de tolérance aux fautes active. Egalement, nous avons proposé une nouvelle technique de tolérance aux fautes des actionneurs pour un drone octorotor coaxial. Cette technique est basée sur une loi de commande robuste avec des gains reconfigurables "self tuning sliding mode control (STSMC)", où les gains de contrôle sont réajustés en fonction de l'erreur détectée afin de maintenir la stabilité du système. Des expériences à l'intérieur ont été menées pour montrer et comparer notre solution avec deux autres techniques de tolérances aux fautes. L'efficacité et le comportement de chaque méthode ont été étudiés après des injections de fautes successives dans les actionneurs. Les principaux avantages et inconvénients de chaque méthode sont déduits en analysant les résultats obtenus. En outre, nous proposons une approche pour la tolérance aux fautes des capteurs et mécanismes logiciels de fusion de données du drone. Cette approche est basée sur la redondance des capteurs et la diversification des composants logicielsThe aim of this work is to propose mechanisms for multirotor drones that allow, on the one hand, to tolerate faults on the drone, and on the other hand to take into account the effects of the wind outdoors. The faults targeted include fault in actuators, sensors, but also software faults on the data fusion algorithms. ln our work, we have developed a robust controller and an exterior disturbance observer capable of cooperating with th, contrai reconfiguration method, to simultaneously tolerate motor failures and exterior wind disturbances through active fault tolerance techniques… We have also proposed a new technique for tolerating actuator faults for a coaxial octorotor drone. This technique is based on a robust command law with reconfigurable "self tuning sliding mode control (STSMC)" gains, where the control gains are readjusted according to the detected error in order to maintain the stability of the system. lndoor experiments are conducted to show and compare our solution with two other fault tolerance techniques. The efficiency and behavior of each method are studied after successive fault injections into the actuators. The main advantages and disadvantages of each method are deduced by analyzing the results obtained. Additionally, we provide an approach for fault tolerance of drone data fusion sensors and software mechanisms. This approach is based on the redundancy of sensors and the diversification of software components
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Boudjaoui, Selim. "Développement et optimisation de capteurs de gaz à base de silicium : analyse des composés organiques volatils contenus dans l’air expiré par les patients atteints d’insuffisance cardiaque." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1113/document.
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Les travaux développés dans ce manuscrit de thèse entrent dans le cadre du projet européen intitulé « Hearten », « A co-operative mHealth environment targeting adherence and management of patients suffering from Heart Failure (HF) ». Les acteurs de ce projet cherchent à développer une plateforme réseau multi compétences dont le but est le diagnostic précoce et le suivi des patients atteints d'insuffisance cardiaque. Elle permet l'enregistrement de différents paramètres vitaux de ces patients, comme la pression artérielle, le poids, les biomolécules contenus dans les biofluides, et leur consultation immédiate par les différents acteurs en charge du suivi des patients. L'objectif des travaux de recherche présentés dans ce manuscrit est de développer un capteur de gaz conductimétrique portable et miniaturisé, permettant la mesure en temps réel des VOCs caractéristiques du syndrome HF dans l'air expiré par les patients. La molécule d'acétone, connue dans la littérature pour être l'un des biomarqueurs les plus discriminants d'HF, a été particulièrement ciblée. Le capteur ainsi conçu est formé de paires de microélectrodes interdigitées (µIDEs) en or déposées sur substrat de silicium. La partie sensible du capteur consiste en une membrane polymérique électro-déposée à la surface du capteur qui est sensible à l'acétone. Les paramètres géométriques des µIDES ont été analysés et optimisés au cours de ces travaux afin d'améliorer la réponse et la sensibilité du capteur. Une plateforme d'analyse des gaz contenant l'ensemble de l'instrumentation associée à notre capteur a été développé. Les paramètres de l'instrumentation ont également été analysés et optimisés dans le même but. Nous avons ainsi étudié deux types de membranes polymériques sensibles à l'acétone. La première couche sensible développée est basée sur la co-polymérisation d'un polymère et de nanomatériaux dopants, le chitosan et les zéolites. La seconde couche sensible développée est quant à elle basée sur la co-polymérisation de polypyrrole et de métallophthalocyanines. Le capteur développé présente des performances optimales pour ce projet, dont notamment une limite de détection de l'ordre du ppm, ainsi que des temps de réponse et de recouvrement très courts. L'utilisation de ce capteur dans le cas de mesures cliniques est ainsi très prometteuse puisqu'il permet d'analyser plusieurs échantillons en temps réel, et ceux sur une durée de fonctionnement de plus d'une semaine. Le diagnostic rapide et la prise en charge du patient est donc facilité grâce à ce dispositif, dont les couts de fabrication sont très réduitsThe work presented in this manuscript is part of the European project « Hearten », « A co-operative mHealth environment targeting adherence and management of patients suffering from Heart Failure (HF) ». The actors of this project are seeking for developing a multi-competence network platform whose goal is the early diagnosis and follow-up of patients with heart failure. It allows the recording of various vital parameters of these patients, such as blood pressure, weight, biomolecules contained in biofluids, and their immediate consultation by the different actors in charge of patient follow-up.The objective of research presented in this manuscript is to develop a portable conductometric gas sensor, allowing the measurement of characteristic VOCs of HF syndrome in exhaled air by patients. Acetone molecule, known in the literature as one of the most discriminating biomarkers of HF, has been particularly targeted. The sensor thus designed is based on pairs of gold interdigitated microelectrode etched on a silicon substrate. The sensitive part of the sensor consists of a polymeric membrane sensitive to acetone and electro-deposited on the surface of the sensor. The geometrical parameters of the µIDES have been analyzed and optimized during these works to improve the response and sensitivity of the sensor. A gas analysis platform including all the instrumentation associated with our sensor has been developed. The instrumentation parameters have also been analyzed and optimized for the same purpose.We studied two types of polymeric membranes sensitive to acetone. The first sensitive layer developed was based on the co-polymerization of a polymer and doping nanomaterials, chitosan and zeolites. The second sensitive layer developed was based on the co-polymerization of polypyrrole and metallophthalocyanines. The developed sensor provides optimal performance for this project, including a detection limit in the order of ppm level, as well as very short response and recovery times. The sensor can therefore be considered in the case of clinical measurements.The use of this sensor in the case of clinical measurements is very promising because it allows to analyze several samples in real time, and those over a period of operation of more than one week. Rapid diagnosis and patient management is therefore facilitated by this device, whose manufacturing costs are very low
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Martins, Leonardo Guedes da Luz. "MÉTODO HÍBRIDO DE DETECÇÃO DE DEFEITOS EM REDES DE SENSORES MÓVEIS UTILIZANDO ALGORITMO DE LOCALIZAÇÃO." Universidade Federal de Santa Maria, 2012. http://repositorio.ufsm.br/handle/1/5412.
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The technological advances resulting from electronic systems miniaturization were crucial to the reach of current technology. The microelectronics and studies to reduce power consumption in electronic devices provided that mobile sensor networks become increasingly used. A mobile sensor network is composed of several sensors nodes, which work collaboratively to achieve a certain goal. Each network node has layers and applications for specific purposes, two of the most important algorithms present in most applications in sensor networks are failure detectors and localization algorithms.
Failure detectors are algorithms that check faulty nodes in the network by exchanging messages. This algorithm is a fundamental block in distributed applications and fault tolerant. Moreover, the localization algorithm is an alternative to GPS use. Using the content of messages transmitted by nodes, the algorithm computes a location coordinates of the node from a reference point.
Several methodologies have been proposed in literature for both algorithms. However, even with functional similarities are not found searches uniting these algorithms in one in order to save resources and improve efficiency in wireless sensor networks.
This study proposes a hybrid method in which the failure detector takes advantage of messages sent by localization algorithm to perform its task. This solution optimizes the messages exchange sent by nodes, reducing the transmission of data packets. As result, the solution reduces the power consumption of nodes and improves system performance.Os avanços tecnológicos decorrentes da miniaturização de sistemas eletrônicos nas últimas décadas foram determinantes para o alcanço da tecnologia atual. A microeletrônica, em conjunto com estudos de redução de consumo de energia em dispositivos eletrônicos, propiciou que as redes de sensores móveis se difundissem rapidamente ao redor do mundo. Uma rede de sensores móveis é composta por diversos nodos sensores, que trabalham colaborativamente para alcançar um determinado objetivo. Cada nodo da rede possui camadas e aplicações com fins específicos, dois dos mais importantes algoritmos presentes na maioria das aplicações em redes de sensores são os detectores de defeitos e os algoritmos de localização. Os detectores de defeitos são algoritmos que normalmente são executados na camada de aplicação e seu objetivo é detectar através da troca de mensagem entre eles possíveis nodos falhos na rede. O algoritmo detector de defeitos é bloco fundamental em aplicações distribuídas e tolerantes a falhas. Por outro lado, o algoritmo de localização é uma proposta alternativa a utilização do GPS. Por meio da troca de mensagem entre os nodos, a partir de um ponto de referência o algoritmo de localização calcula as coordenadas do nodo no espaço. Diversas metodologias já foram propostas na bibliografia para ambos os algoritmos. Porém, mesmo com similaridades funcionais, não são encontradas pesquisas que integrem estes algoritmos, a fim de economizar recursos e melhorar a eficiência das redes de sensores. Este trabalho propõe um método híbrido em que o detector de defeitos aproveita a troca de mensagens realizada pelo algoritmo de localização para realizar sua tarefa. A solução aperfeiçoa a troca de mensagens enviadas pelos nodos, evitando o envio de pacotes de dados. Como resultado, a solução diminui o consumo de energia dos nodos e melhora o desempenho do sistema.
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Novotný, Bohumil. "Multiplatformní komunikace v přístupových sítích." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2017. http://www.nusl.cz/ntk/nusl-364613.
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Doctoral thesis deals with failure detection methods in wireless access network using distributed stochastic algorithms. A new method of detecting a fault based on the push-sum algorithm has been designed and simulated. Within the scope of the work objectives, the statistical credibility of the average push-sum protocol convergence rate representative and the effect of message loss during the calculation on the robustness of the system using this protocol were compared. Based on the acquired knowledge, the ability of the protocol to mathematically derive deviations from the real average of the values in the specified topology was demonstrated and thereby the existence of an abnormality in the network has been proved or refuted.
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Lutz, Mary Laura. "An exploration of the relationship between failed senior pastor appointments in three large United Methodist churches and seminary preparation, professional identity, and person-environment." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1196185082.
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Bousghiri, Souad. "Diagnostic de fonctionnement des procédés continus par réconciliation d'état généralisé : application à la détection de pannes de capteurs et d'actionneurs." Nancy 1, 1994. http://www.theses.fr/1994NAN10396.
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Les travaux présentés, dans ce mémoire, concernent l'étude de la détection et de la localisation de défauts de fonctionnement de capteurs ou d'actionneurs de systèmes continus en régime dynamique. Après un rappel sur la notion de détection, nous présentons différentes approches du diagnostic en insistant plus particulièrement sur les méthodes utilisant la rebondance analytique. Un bref aperçu de la théorie de la réconciliation de données est exposée. Différentes méthodes permettant une estimation simultanée des états et des commandes (état généralisé) sont présentées dans le cas général, c'est-à-dire dans le cas où toutes les grandeurs ne sont pas nécessairement mesurées. La solution proposée donne une estimation en temps diffère, car du point de vue temps et volume de calcul, son application directe s'avère inexploitable. A partir de la formulation du problème d'estimation, nous donnons des solutions adaptées à un traitement en ligne sous deux formes. La première forme montre que l'estimation est une fonction linéaire des mesures antérieures. La seconde forme est récursive, la solution à l'instant courant est fonction de celle obtenue à l'instant précédent. Pour cette seconde forme, nous utilisons la formulation des systèmes singuliers pour l'estimation de l'état et de la commande. Ces méthodes sont comparées sur des exemples permettant de mieux cerner les avantages et les inconvénients de chacune d'entre elles pour une application au diagnostic. Nous présentons ensuite, compte tenu du choix de l'estimateur à fenêtre glissante, une stratégie de détection et de localisation de défaut de capteurs ou d'actionneurs. La sensibilité de l'estimateur vis-à-vis des incertitudes de modèle est alors abordée. Nous développons ensuite une fonction de localisation de l'élément défaillant. L'application à deux systèmes réels: un pendule inversé et un procède hydraulique, montre les bonnes qualités de notre stratégie
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Abeykoon, A. Gedara Tharindu Bhagya Bandara. "Developing an economical and reliable real-time warning system for rainfall-induced individual landslides." Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/227324/1/A%20Gedara%20Tharindu%20Bhagya%20Bandara_Abeykoon_Thesis.pdf.
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This project was a step forward in developing a reliable, economical and accurate real-time warning system for rainfall-induced individual landslides based on physical-based, optimised slope monitoring and statistical and numerical approaches. The physical-based system involved experimental and numerical analyses in implementing a low-cost slope monitoring system in critical slopes in North Maleny, evaluating parameters of tilt angle (and tilt rate), the volumetric water content of soil and rainfall. The thesis further investigated auxiliary landslide prediction approaches, including rainfall intensity–duration thresholds and analytical time to failure predictions to enhance the accuracy and reliability of outcomes.
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Júnior, Amleto Landucci. "Manutenção pré-corretiva em transformadores de potência: um novo conceito de manutenção." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/18/18154/tde-01092009-112719/.
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Um importante diferencial competitivo das empresas distribuidoras de energia elétrica é a gestão da utilização dos seus ativos elétricos. Dentre eles destaca-se o transformador de potência em função de sua importância estratégica no fornecimento de energia aos grandes centros de carga. Para minimizar os impactos operacionais e sociais associados às interrupções constantemente monitoradas para que haja controle efetivo e garantia de funcionamento adequado e otimizado. O monitoramento das suas principais características é um ponto crítico que deve ser constantemente aprimorado, pela indiscutível importância destes ativos elétricos na continuidade do fornecimento de energia elétrica. Este trabalho apresenta proposta para avaliação em tempo real de falhas em transformadores de potência, para que sejam monitorados remotamente pela distribuidora, através do seu respectivo centro de operação do sistema elétrico, propiciando assertividade e rápida tomada de decisão gerencial em ocorrências de falhas internas, reduzindo os custos associados à interrupção do fornecimento de energia elétrica, diminuindo significativamente os tempos de restabelecimento do fornecimento e consequentemente minimizando impactos nos principais Indicadores de qualidade operacional da distribuidora.An important competitive edge of electric power distribution companies is their electric assets utilization management. Among them stands outs the power transformers because of its strategic importance in the energy supply to high demand areas. To minimize operational and social impacts associated to the electric energy supply interruptions these equipments must to have their main characteristics constantly monitored to have effective control and optimizer functioning warranty. The main characteristics monitoring is a critical point which must be constantly improved, for the unquestionable importance of these electric assets in the electric energy supply continuity. This work shows a proposal to the real time power transformer failure, to remote monitoring by the utilities thru its respective electric system operation center, enabling assertively and fast management decision making in internal failure occurrences, reducing costs associated with electric energy supply interruption, decreasing the supply reestablishing times and consequently minimizing the impacts on the main distribution operational quality indicators.
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Santos, Elaine Cristina Vasconcelos dos. "Insucesso escolar: o ponto de vista das crianças que o vivenciaram." Pontifícia Universidade Católica de São Paulo, 2010. https://tede2.pucsp.br/handle/handle/15952.
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This study, which can be inserted in socio-historical tradition of Psychology, investigated senses and meanings attributed by children to their unsuccessful school experiences. Seeking to fight school failure, it attempts to explore how children view such issues, aiming to make a positive contribution to the discussion of educational status in Brazil. The participants were two 10-year-old students, a boy and a girl, who faced, according to the teacher, difficulties to follow explanation and, therefore, were taking the risk of missing a school year. The children were attending 5th grade of primary school, in a public institution in São Paulo City. The method involved one month systematic classroom observation in 2010, complimented by interviews with classroom teacher and individual meetings with mentioned students. During those occasions, the students described how they viewed school, their teachers and school experience, while drawing situations related to those matters. Data systematization and analysis were collected in compliance with procedures recommended by Aguiar and Ozella (2006), building clutters of meanings, through construction and agglutination of indicators. Data were interpreted under a socio-historical theory perspective, presenting, among other things, children doing homework with fear and intense pain, whilst becoming progressively skeptical about their skills to meet criteria which define a good student. Under such circumstances, school wastes its function and purposes: ability to comprise an adequate mediation, in order to provide important learning and, consequently, development of new possibilities of being. Recommendations are made in terms of both initial and continuous teachers training, with emphasis on ethical and political aspects which are involved in teachers occupation
Esse estudo, que se insere na vertente sócio-histórica em Psicologia, investigou os sentidos e os significados que crianças atribuem as suas experiências escolares mal sucedidas. Ao inserir-se na tradição que procura combater o fracasso escolar, buscou explorar o ponto de vista infantil sobre essa questão, no sentido de contribuir na discussão acerca da situação educacional brasileira. Participaram da pesquisa dois alunos de 10 anos, uma menina e um menino, que apresentavam, segundo seu professor, dificuldades para acompanhar a turma e, por esse motivo, estavam arriscados a perderem o ano. As crianças cursavam o 5º ano do Ensino Fundamental I, em uma escola vinculada à rede pública paulista. O método envolveu observação sistemática em sala de aula, durante o período de um mês do ano letivo de 2010, além de entrevistas com o professor da classe e encontros individuais, no contraturno, com os alunos, momentos em que desenharam e contaram sua forma de ver a escola, seus professores e a experiência escolar. A sistematização e análise dos dados foram realizadas recorrendo-se aos procedimentos sugeridos por Aguiar e Ozella (2006), segundo o qual se constroem, via identificação de pré-indicadores e indicadores, núcleos de significação. Os dados foram interpretados à luz da teoria sócio-histórica e sua análise demonstrou, entre outras coisas, que as crianças vivem com temor e intenso sofrimento diante das tarefas propostas pelo docente, descrentes que são de sua capacidade de alcançar os critérios de bom aluno. A escola, nessas circunstâncias, perde sua função e principal objetivo: constituir-se em mediação adequada, capaz de promover aprendizagens importantes e, conseqüentemente, o desenvolvimento que permite novas possibilidades de aprender. Recomendações são feitas em termos de formação inicial e continuada de professores, com ênfase nos aspectos éticos e políticos inerentes à profissão docente