Dissertations / Theses on the topic 'Ice Detection'
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Drummond, Krista. "Polarimetric road ice detection." Thesis, The University of Arizona, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1572997.
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This thesis investigated the science behind polarimetric road ice detection systems. Laboratory Mueller matrix measurements of a simulated road under differing surface conditions were collected searching for a discriminatory polarization property. These Mueller matrices were decomposed into depolarization, diattenuation, and retardance. Individual sample surface polarization properties were then calculated from these three unique matrices and compared. Specular and off-specular reflection responses of each sample were collected. Four polarization properties stood out for having high separation between dry and iced measurements: Depolarization Index, Linear Diattenuation, Linear Polarizance, and Linear Retardance.
Through our investigation polarimetric ice detection is possible. Continued research of the polarization properties of road ice can result in the development of a road ice detection system. Proposed deployment methods of such a system have been outlined following the analysis of the data collected in this experiment.
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Drummond, Krista. "Polarimetric Road Ice Detection." Thesis, The University of Arizona, 2014. http://hdl.handle.net/10150/347115.
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Ever since automobiles became affordable for the average American, with the introduction of the Ford Model T in 1908, making driving safer has been a priority. While driver intoxication and distraction are the leading causes of automotive fatalities, poor road conditions increase the frequency and deadliness of these incidents. Monitoring road conditions for thousands of miles of road is a huge undertaking, one too large for human surveillance. Automated systems capable of detecting and reacting to dangerous road conditions would be life-saving. These systems could be mounted to the sides of road and notify an operator of conditions in real-time. Drivers could be warned, action taken, and many lives saved. This thesis investigated the science behind polarimetric road ice detection systems. Laboratory Mueller matrix measurements of a simulated road under differing surface conditions were collected searching for a discriminatory polarization property. These Mueller matrices were decomposed into depolarization, diattenuation, and retardance. Individual sample surface polarization properties were then calculated from these three unique matrices and compared. Simulated road samples were measured under many wavelengths and angles, which gave us a larger data library from which to observe trends. Specular and off-specular reflection responses of each sample were also collected. Four polarization properties stood out for having high separation between dry and iced measurements: Depolarization Index, Linear Diattenuation, Linear Polarizance, and Linear Retardance. Through our investigation polarimetric ice detection is possible. Continued research of the polarization properties of road ice can result in the development of a road ice detection system. Proposed deployment methods of such a system have been outlined following the analysis of the data collected in this experiment. Not only is polarimetric ice detection an exciting and novel use of polarization, it has the potential to improve road safety through real-time ice response measures.
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Sohn, Hong-Gyoo. "Boundary detection using multisensor imagery: Application to ice sheet margin detection /." The Ohio State University, 1996. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487942476406942.
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Christner, Brent C. "Detection, recovery, isolation, and characterization of bacteria in glacial ice and Lake Vostok accretion ice." The Ohio State University, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=osu1015965965.
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Christner, Brent Craig. "Detection, recovery, isolation and characterization of bacteria in glacial ice and Lake Vostok accretion ice /." The Ohio State University, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=osu1486402288260857.
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Dershowitz, Adam L. (Adam Lee) 1967. "A passive infrared ice detection technique for helicopter applications." Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/44271.
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Böser, Sebastian. "Acoustic detection of ultra-high energy cascades in ice." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2007. http://dx.doi.org/10.18452/15670.
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Existierende Neutrinoteleskope sind für den Nachweis von Neutrinos aus astrophysikalischen Quellen mit Energien im TeV Bereich optimiert. Aufgrund der geringen Flüsse und Wirkungsquerschnitte wurden bislang keine extraterrestrischen hochenergetischen Neutrinos beobachtet. Erst die im Bau befindlichen kubikkilometer-großen Cherenkov-Neutrinodetektoren werden das notwendige Volumen haben, um diese nachzuweisen. Für Neutrinos aus Wechselwirkungen der kosmischen Strahlung im EeV-Bereich mit dem kosmischen Mikrowellenhintergrund wird dennoch nicht mehr als ein Ereignis im Jahr erwartet. Nachweisvolumen in der Größenordnung von 100 km^3 sind notwendig, um den Fluß dieser Neutrinos zu bestimmen und die vorhergesagten Wirkungsquerschnitte zu überprüfen. Alternative Meßtechniken sind erforderlich, um einen Detektor dieses Ausmaßes zu realisieren. Eine vielversprechende Idee ist die Erfassung akustischer Wellen aus den in der Neutrinowechselwirkung erzeugten hadronischen Kaskaden. Aufgrund der höheren Signalstärke und der großen Schalldämpfungslängen ist die Eisdecke des Südpols dem Wasser der Ozeane als Medium vorzuziehen. Zunächst sind jedoch geeignete Sensoren, eine Überprüfung der thermo-akustischen Schallerzeugung und Kenntnisse der akustischen Eigenschaften des Eises von Nöten. In einer theoretischen Ableitung konnte die Äquivalenz der Mechanismen der Erzeugung akustischer Wellen durch thermo-elastische Anregung in Flüßigkeiten und isotropen Festkörpern gezeigt werden. Einer Analyse des existierenden Wissensstandes folgte die Simulation eines kombinierten Cherenkov-Radiowellen-Ultraschall-Detektors. Für den Einsatz im Eis wurden spezielle akustische Sensoren entwickelt und zur Erfassung der Schallemission von intensiven Protonen- und Laserstrahlen eingesetzt. Darauf aufbauend wurde ein akustische Sender- und Empfänger-Aufbau entwickelt, mit dem Ziel, die Ultraschalleigenschaften des südpolaren Eises in-situ zu untersuchen. Die Ergebnisse dieser ersten Bemühungen werden in dieser Arbeit vorgestellt.Current neutrino telescopes are designed to detect neutrinos with energies in the TeV range. Due to the low fluxes and small cross sections, no high energy neutrinos of extraterrestrial origin have been observed so far. Only the Cherenkov neutrino detectors on the km^3 scale that are currently under construction will have the necessary volume to observe these rare interactions. Yet, for neutrinos from interactions of the ultra-high energy cosmic at EeV energies rays with the ambient cosmic microwave background, event rates of only one per year are expected. To measure the flux and verify the predicted cross sections of these cosmogenic neutrinos, an observed volume of around 100 km^3 will be necessary, that will not be feasible with existing detection techniques. Alternative methods are required to build a detector on these scales. One promising idea is to record the acoustic waves generated in cascades following the neutrino interaction. Higher amplitudes of the sonic signal and the large absorption length of sound favour South Polar ice instead of sea water as a medium. For an estimate of the potential of such a detector, suitable acoustic sensors, a verification of the model of thermo-acoustic sound generation and a determination of the acoustic properties of the ice are necessary. In a theoretical derivation the mechanism of thermo-elastic excitation of acoustic waves was shown to be equivalent for isotropic solids and liquids. A detailed analysis of the existing knowledge and a simulation study of a hybrid optical-radio-acoustic detector have been performed. Ultrasonic sensors dedicated to in-ice application were developed and have been used to record acoustic signals from intense proton and laser beams. Based on this, the hitherto largest array of acoustic sensors and transmitters was devised and implemented, with the aim to study the ultrasonic properties of the South Polar ice in-situ. Results from all of these first efforts are presented.
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Carlsson, Viktor. "Measuring routines of ice accretion for Wind Turbine applications : The correlation of production losses and detection of ice." Thesis, Umeå universitet, Institutionen för fysik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-37896.
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Wind power will play a major role in the future energy system in Sweden. Most of the major wind parks are planned to be built in sites where the cold climate and atmospheric icing can cause serious problems. This underlines the importance of addressing these issues. The major cause of these problems is in-cloud icing of the rotor blades due to super cooled liquid droplets of clouds. The droplets freeze upon impact with the rotor blade and form hard rime ice. This rime ice causes disruption in the aerodynamics that leads to production losses, extra loads on the rotor blades and when the ice is shed it poses a safety risk to people in the near environment. This master thesis focuses on how to measure the accretion of ice and the correlation between measured ice and production losses of two wind parks in northern Sweden. The results show a good correlation between the ice accretion on a stationary sensor and the production loss from a wind turbine. In most icing events the icing of the sensor and large production losses from the wind turbine correlated clearly. Attempts to quantify the production losses at a certain ice rate measured with the stationary sensors was done, however no clear results was produced. The reason for this is that the wind turbines often stop completely during an icing event and that the time series analyzed was too short to be able to quantify the losses at certain wind speed and ice rates. Recommendations on the type of sensor which should be used was to be produced, however the conclusion was that no single sensor has acted satisfactory and could be recommended to measure ice accretion for wind turbine applications. Due to this, at least two sensors are recommended to increase the redundancy in the measurement system. Modeling ice accretion with standard parameters measured has been done and the results show that the time of icing could be determined quite well when the sensors was ice free, however when the sensors and especially the humidity sensors was iced the time of icing was overestimated. The main conclusion drawn is that there is a clear relationship between the icing of a stationary sensor and the rotor blade. There is still no which fulfills all demands of measuring ice accretion for wind turbine applications, further it is possible with simple models to roughly determine when icing occurs with standard measurements.
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Eriksson, Carl-Johan. "Wireless Weather Station for the detection of black ice on roads." Thesis, Linköpings universitet, Institutionen för teknik och naturvetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-80470.
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Att hålla de svenska vägarna säkra under vinterhalvåret är något som kräver stora resurser och kostar samhället stora pengar. De system som idag finns för att ge information om hur väg förhållandena ser ut är inte tillräckliga. Det finns för få väderstationer utplacerade runt om i vägnätet för att kunna ge en bra geografisk upplösning åt de som beslutar om ut dirigering av insatser. Att ta fram en kostnadseffektiv och helt trådlös väderstation som kan placeras ut oavsett tillgång till strömförsörjning eller trådbunden kommunikation är något som funnits som önskan hos de stora aktörerna inom vinterväghållningen i Sverige en längre tid. Vid ökad geografisk upplösning av väderförhållandena i vägnätet kommer det möjliggöras mer riktade insatser av vinterväghållningen. Detta skulle resultera i minskat slitage på verktyg samt minskat användande av salt på vägbanan vilket innebär ekonomiska vinster och inte minst miljömässiga vinster. Intervjuer och enkätsvar har legat till grund för framtagning av ett underlag för en väderstation av detta slag. Under arbetet med väderstationens underlag har ytterligare önskemål och idéer från människor som är aktiva inom branschen dykt upp. Detta har lett till att examensarbetet inriktat sig framför allt på att ta fram ett nytt sensorsystem som helt kontaktfritt från vägbanans yta detekterar vad som finns på vägytan när det gäller torr, våt eller isig vägbanan. Ett komplett sensorsystem har utvecklats som placeras i vägbanan och mäter temperaturen samt helt kontaktfritt från vägytan detektera om vägbanan är torr, våt eller om det finns is på den. Sensorsystemet är helt batteriförsörjt och skickar data helt trådlöst från vägbanan. Detta gör det möjligt att använda flera sensorer i vägbanan och på detta sätt skapa ett sensornätverk som kan avgöra hur förhållandena ser ut på längre sträckor än i dagsläget endast i en punkt.Keeping the Swedish roads safe during winter months is something that requires large resources and costs society a lot of money. The systems that provide information on road condition today are not enough. There are too few weather stations located around the road network to provide a good spatial resolution to those who decide if there is a need for ice- or snow removal on the roads. To provide a cost effective and completely wireless weather station that can be deployed regardless of access to power or wired communications is something that existed as a desire by the major contractors for the winter road maintenance in Sweden for a long time. A higher spatial resolution of weather conditions in the road network will make it possible to use more focused efforts where the road conditions are not good. This would result in reduced wear on the tools, less fuel consumption and reduced use of salt on the roadway resulting in economic gains and not least environmental benefits. Interviews and questionnaires were the basis for creating a base for a weather station of this kind. While working on weather station data, additional requests and ideas from people who are active in the industry emerged. This has led to the thesis work focused primarily on developing a new sensor system that completely contact-free from the road surface detect what is on the road surface when it comes to distinguish dry, wet or icy road surface. A complete sensor system has been developed that is placed in the roadway and which measures the temperature and uses a sensor that doesn't have any contact with the road surface to detect if the road surface is dry, wet, or if there is ice on it. The sensor system is battery powered and transmits data wirelessly from the road. This makes it possible to use multiple sensors in the roadway, thereby creating a sensor network that can determine what the conditions are at longer distances than in only one point.
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Koçer, Zeynep A. "Detection of Influenza A Viruses From Environmental Lake and Pond Ice." Bowling Green State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1276804585.
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Jack, Landy. "Characterization of sea ice surface topography using Light Detection and Ranging (LiDAR)." Wiley, 2014. http://hdl.handle.net/1993/31170.
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Where once the Arctic basin held predominantly old, thick perennial sea ice, it is now increasingly occupied by young, thin seasonal ice. The sea ice surface topography, which affects and is affected by many of the physical processes operating at the interface between ocean, sea ice and atmosphere, is closely related to the age and type of sea ice cover. In this thesis, new methods are presented for measuring and understanding sea ice topography using Light Detection and Ranging (LiDAR) technology.
A new technique is presented for parameterizing the micro-scale roughness of sea ice using terrestrial LiDAR. Field, laboratory and numerical experiments have been carried out to test the precision and accuracy of the technique, and calibrations have been developed for correcting field observations of surface roughness for known biases. Results obtained using this technique have been applied in several microwave remote sensing and electromagnetic-wave scattering model studies of snow-covered and melting sea ice.
Terrestrial and satellite LiDAR observations are acquired and combined in a further study to examine how sea ice surface topography regulates the melting of ice during the Arctic summer. Observations from a field program in the Canadian Arctic show that minor variations in the roughness of pre-melt sea ice topography can affect significant variations in the melt pond coverage at the ice surface in summer. Numerical simulations are used to develop a quantitative understanding of these findings and, when applied to satellite observations, explain most of the spatial variation in Arctic summer ice melting rates. Results suggest that a recent reduction in sea ice roughness, caused by progressive changes in the type of sea ice resident in the Arctic Ocean, has accelerated the summer melting and decline of the Arctic sea ice cover.May 2016
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Werger, Jade. "Decision-making in ice hockey referees : officiating style and accurate detection of penalties." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/63405.
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Examining officiating in ice hockey has received limited attention, particularly in the area of decision-making at the grassroots, minor ice hockey level. The primary purpose of this research was to create a video tool from hockey game footage and examine minor hockey officials’ decision-making in the context of officiating style and experience. Minor hockey officials possessing three levels of officiating experience: (1) 1 y (n = 10), (2) 2 to 4 y (n = 13), and (3) 5 to 9 y (n=10) completed a Video-Based Infraction Detection Task. Referees were shown video clips of potential penalty scenarios from female AAA Bantam and Midget hockey games, according to four game information conditions: (1) No Information, Randomized (NR); (2) No Information, Sequential (NS); (3) Information, Randomized (IR); and (4) Information, Sequential (IS). Specifically, referees received game information (e.g., score) or no game information prior to clip viewing; and the clips were presented randomly or in the sequential order that they occurred during game play. After viewing each clip, referees were asked to determine whether an infraction occurred. The accuracy of the referee’s detection performance was calculated using Signal Detection Theory. A 3 (experience group) x 4 (condition) mixed factorial ANOVA, with repeated measures on the last factor, revealed that all officials performed similarly on the detection task irrespective of experience. A main effect was found for condition, F (3,90) = 40.0, p < .001 and post-hoc comparisons showed superior accuracy in the IR condition (81.8% ± 1.4), followed by the IS condition (74.3% ± 1.5), NS condition (68.5% ± 1.4), and NR condition (60.0% ± 2.2). These findings suggest that game information may assist referees attentional focus to the task, as well as put the referee into the context of the game resulting in superior performance for detecting an infraction. The data is discussed in the context of using video-based protocols for training hockey referees at the grassroots level of officiating. This work also provides future directions and recommendations for the development of video scenarios for referee training, including the incorporation of common stressors identified by minor hockey officials across experience levels.Education, Faculty of
Kinesiology, School of
Graduate
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Kunz, Lukas Brad. "A New Method for Melt Detection on Antarctic Ice-Shelves and Scatterometer Calibration Verification." Diss., CLICK HERE for online access, 2004. http://contentdm.lib.byu.edu/ETD/image/etd527.pdf.
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Semburg, Benjamin [Verfasser]. "HADES - an acoustic sensor for neutrino detection in ice Calibration, characterization andmeasurements / Benjamin Semburg." Wuppertal : Universitätsbibliothek Wuppertal, 2011. http://d-nb.info/101170935X/34.
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Bravo, Jimenez Ismael. "Detection and removal of wind turbine ice : Method review and a CFD simulation test." Thesis, Högskolan i Gävle, Energisystem, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-27798.
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Nowadays, the energy sector is facing a huge demand that needs to be covered. Wind energy is one of the most promising energy resources as it is free from pollution, clean and probably will arise as one of the main energy sources to prevent global warming from happening. Almost 10% of the global energy demand is coming from renewable resources. By 2050 this percentage is expected to grow to 60%. Therefore, efforts on wind turbine technology (i.e. reliability, design…) need to be coped with this growth. Currently, large wind energy projects are usually carried out in higher altitudes and cold climates. This is because almost all of the cold climates worldwide offer profitable wind power resources and great wind energy potential. Operating with wind turbines in cold climates bring interesting advantages as a result of higher air density and consequently stronger winds (wind power is around 10% higher in the Nordic regions). Not only benefits can be obtained but extreme conditions force to follow harsh conditions. Low temperatures and ice accretion present an important issue to solve as can cause several problems in fatigue loads, the balance of the rotor and aerodynamics, safety risks, turbine performance, among others. As wind energy is growing steadily on icy climates is crucial that wind turbines can be managed efficiently and harmlessly during the time they operate. The collected data for the ice detection, de-icing and anti-icing systems parts was obtained through the company Arvato Bertelsmann and is also based on scientific papers. In addition, computer simulations were performed, involving the creation of a wind tunnel under certain conditions in order to be able to carry out the simulations (1st at 0ºC, 2nd at -10ºC) with the turbine blades rotating in cold regions as a standard operation. In this project, Computational Fluids Dynamics (CFD) simulation on a 5MW wind turbine prototype with ice accretion on the blades to study how CL and CD can change, also different measures of ice detection, deicing and anti-icing systems for avoiding ice accumulation will be discussed. Simulation results showed a logical correlation as expected, increasing the drag force about 5.7% and lowering the lift force 17,5% thus worsening the turbine's efficiency.
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Fröjse, Linda. "Unsupervised Change Detection Using Multi-Temporal SAR Data : A Case Study of Arctic Sea Ice." Thesis, KTH, Geodesi och geoinformatik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-147007.
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The extent of Arctic sea ice has decreased over the years and the importance of sea ice monitoring is expected to increase. Remote sensing change detection compares images acquired over the same geographic area at different times in order to identify changes that might have occurred in the area of interest. Change detection methods have been developed for cryospheric topics. The Kittler-Illingworth thresholding algorithm has proven to be an effective change detection tool, but has not been used for sea ice. Here it is applied to Arctic sea ice data. The objective is to investigate the unsupervised detection of changes in Arctic sea ice using multi-temporal SAR images. The well-known Kittler-Illingworth algorithm is tested using two density function models, i.e., the generalized Gaussian and the log-normal model. The difference image is obtained using the modified ratio operator. The histogram of the change image, which approximates its probability distribution, is considered to be a combination of two classes, i.e., the changed and unchanged classes. Histogram fitting techniques are used to estimate the unknown density functions and the prior probabilities. The optimum threshold is selected using a criterion function directly related to classification error. In this thesis three datasets were used covering parts of the Beaufort Sea from the years 1992, 2002, 2007 and 2009. The SAR and ASAR C-band data came from satellites ERS and ENVISAT respectively. All three were interpreted visually. For all three datasets, the generalized Gaussian detected a lot of change, whereas the log-normal detected less. Only one small subset of a dataset was validated against reference data. The log-normal distribution then obtained 0% false alarm rate through all trials. The generalized Gaussian obtained false alarm rates around 4% for most of the trials. The generalized Gaussian achieved detection accuracies around 95%, whereas the log-normal achieved detection accuracies around 70%. The overall accuracies for the generalized Gaussian were about 95% in most trials. The log-normal achieved overall accuracies at around 85%. The KHAT for the generalized Gaussian was in the range of 0.66-0.93. The KHAT for log-normal was in the range of 0.68-0.77. Using one additional speckle filter iteration increased the accuracy for the log-normal distribution. Generally, the detection of positive change has been accomplished with higher level of accuracy compared with negative change detection. A visual inspection shows that the generalized Gaussian distribution probably over-estimates the change. The log-normal distribution consistently detects less change than the generalized Gaussian. Lack of validation data made validation of the results difficult. The performed validation might not be reliable since the available validation data was only SAR imagery and differentiating change and no-change is difficult in the area. Further due to the lack of reference data it could not be decided, with certainty, which distribution performed the best.Ytan av arktisk havsis har minskat genom åren och vikten av havsisövervakning förväntas öka. Förändrigsdetection jämför bilder från samma geografiska område från olika tidpunkter föra att identifiera förändringar som kan ha skett i intresseområdet. Förändringsdekteringsmetoder har utvecklats för kryosfäriska ämnen. Tröskelvärdesbestämning med Kittler-Illingworth algoritmen har visats sig vara ett effektivt verktyg för förändringsdetektion, men har inte änvänts på havsis. Här appliceras algoritmen på arktisk havsis. Målet är att undersökra oövervakad förändringsdetektion i arktisk havsis med multitemporella SAR bilder. Den välkända Kittler-Illingworth algoritmen testas med två täthetsfunktioner, nämligen generaliserad normaldistribution och log-normal distributionen. Differensbilden erhålls genom den modifierad ratio-operator. Histogrammet från förändringsbilden skattar dess täthetsfunktion, vilken anses vara en kombination av två klasser, förändring- och ickeförändringsklasser. Histogrampassningstekniker används för att uppskatta de okända täthetsfunktionerna och a priori sannolikheterna. Det optimala tröskelvärdet väljs genom en kriterionfunktion som är direkt relaterad till klassifikationsfel. I detta examensarbete användes tre dataset som täcker delar av Beaufort-havet från åren 1992, 2002, 2007 och 2009. SAR C-band data kom från satelliten ERS och ASAR C-band data kom från satelliten ENVISAT. Alla tre tolkades visuellt och för alla tre detekterade generaliserad normaldistribution mycket mer förändring än lognormal distributionen. Bara en mindre del av ett dataset validerades mot referensdata. Lognormal distributionen erhöll då 0% falska alarm i alla försök. Generalised normaldistributionen erhöll runt 4% falska alarm i de flesta försöken. Generaliserad normaldistributionen nådde detekteringsnoggrannhet runt 95% medan lognormal distributionen nådde runt 70%. Generell noggrannheten för generaliserad normaldistributionen var runt 95% i flesta försöken. För lognormal distributionen nåddes en generell noggrannhet runt 85%. KHAT koefficienten för generaliserad normaldistributionen var i intervallet 0.66-0.93. För lognormal distributionen var den i intervallet 0.68-0.77. Med en extra speckle-filtrering ökades nogranneheten för lognormal distributionen. Generellt sett, detekterades positiv förändring med högre nivå av noggrannhet än negativ förändring. Visuell inspektion visar att generaliserad normaldistribution troligen överskattar förändringen. Lognormal distributionen detekterar konsistent mindre förändring än generaliserad normaldistributionen. Bristen på referensdata gjorde valideringen av resultaten svårt. Den utförda valideringen är kanske inte så trovärdig, eftersom den tillgänliga referensdatan var bara SAR bilder och att särskilja förändring och ickeförändring är svårt i området. Vidare, på grund av bristen på referensdata, kunde det inte bestämmas med säkerhet vilken distribution som var bäst.
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Farris-Manning, Peter (Peter James) Carleton University Dissertation Geography. "Ice jam detection and flood monitoring using airborne synthetic aperture radar; Saint John River, New Brunswick, 1987." Ottawa, 1991.
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Klenner, Fabian [Verfasser]. "Experiments for the Detection of Biosignatures in Ice Grains by Space Missions to Enceladus and Europa / Fabian Klenner." Berlin : Freie Universität Berlin, 2021. http://d-nb.info/1228860343/34.
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Kinda, Gnouregma Bazile. "Acoustic remote sensing of Arctic sea ice from long term soundscape measurements." Thesis, Grenoble, 2013. http://www.theses.fr/2013GRENU032/document.
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La fonte rapide des glaces de l'Arctique dans le contexte actuel du réchauffement climatique est un sujet scientifique majeur de ces 30 dernières années. L'Arctique joue un rôle fondamental dans l'équilibre du climat et requiert une attention particulière. Les régions arctiques sont alors surveillées par des observations satellitaires et des mesures in-situ. L'impact climatique de la fonte totale de la glace arctique est encore spéculatif. Des recherches sont donc nécessaires pour le suivi à long terme de l'Océan Arctique, en particulier la dynamique spatio-temporelle de la couverture de glace et ses conséquences sur les écosystèmes. Notre travail s'inscrit dans ce contexte, et est porté sur le paysage sonore des régions polaires avant leur possible industrialisation qui accompagnera la fonte de la glace. Ainsi, nous avons d'abord examiné les conséquences de la disparition du couvert de glace sur les paysages sonores de ces régions. Nous avons alors étudié les variations saisonnières du bruit de fond et ses pilotes environnementaux. De ce fait, nous avons développé un algorithme d'estimation du bruit ambiant afin de pouvoir constituer des séries temporelles à partir des données acoustiques longue durée. Deuxièmement, nous avons étudié les transitoires générés par le comportement mécanique de la banquise en Arctique. Cette étude vise d'une part à comprendre le mécanisme de production de ces transitoires sous la glace, et d'autre part à évaluer leur potentiel comme moyen d'observation de la dynamique de la glace de merThe Arctic sea ice melting, in the global warming context, has become a major scientific topic during the last 30 years. The Arctic Ocean plays a fundamental role in the global climate balance and requires a particular attention. The Arctic Regions are then monitored by satellite observations and in-situ measurements. The climatic impact of the total melting of the Arctic sea ice is not yet understood and researches are still needed for long term monitoring of Arctic Ocean, particularly the dynamics of the ice cover and its consequences on the ecosystems. Our work focused on the natural soundscapes of these Polar Regions prior to their possible industrialization. So, we first examined the impact of climate warming alone on polar soundscapes by studying the seasonal variability of ambient noise and its environmental drivers. We then developed an ambient noise estimation algorithm for automatic extraction of this noise component from long term measurements. In second, we examined the acoustic transients generated by the mechanical behavior of the ice cover at its maximum extent. This aims to better understanding of the physical processes involved in under-ice noise production and their potential use for sea ice monitoring
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Hicks, Brandon R. "Melt Detection and Estimation in Greenland Using Tandem QuikSCAT and SeaWinds Scatterometers." BYU ScholarsArchive, 2006. https://scholarsarchive.byu.edu/etd/940.
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Ku-band dual-polarization radar backscatter measurements from the SeaWinds on QuikScat (QuikScat) and SeaWinds on ADEOS-2 (SeaWinds) scatterometers are used to classify the melt state and estimate melt severity in Greenland. Backscatter measurements are organized into high temporal and high spatial resolution images created using the Scatterometer Image Reconstruction (SIR) algorithm and a new temporal data segmentation technique. Melt detection is performed using a layered electromagnetic model combined with a Markov chain model. The new melt detection method allows classification of the snow-pack into three states: melt, refreeze, and frozen. Melt severity and refreeze severity indexes are also developed. The melt detection methods developed in this thesis are verified by using a one-dimensional geophysical/electromagnetic model simulation of the snow-pack under melting conditions and by comparison with in situ weather station data at the ETH Camp in western Greenland. The diurnal cycle of backscatter measurements is also analyzed at this location. The melt detection and estimation method is applied to the entire Greenland ice-sheet. The resulting melt classifications and melt severity indexes are used to generate a number of maps outlining the features of the 2003 melt season. Good agreement of the melt severity and a 1978 SASS Greenland ice facies map is observed.
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Toprak, Emre [Verfasser], and S. [Akademischer Betreuer] Norra. "Real Time Detection of Primary Biological Aerosol Particles (PBAP) in the context of atmospheric ice formation / Emre Toprak. Betreuer: S. Norra." Karlsruhe : KIT-Bibliothek, 2014. http://d-nb.info/105695597X/34.
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Matra, L., M. A. MacGregor, P. Kalas, M. C. Wyatt, G. M. Kennedy, D. J. Wilner, G. Duchene, et al. "Detection of Exocometary CO within the 440Myr Old Fomalhaut Belt: A Similar CO+ CO2 Ice Abundance in Exocomets and Solar System Comets." IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/624435.
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Recent Atacama Large Millimeter/submillimeter Array observations present mounting evidence for the presence of exocometary gas released within Kuiper Belt analogs around nearby main-sequence stars. This represents a unique opportunity to study their ice reservoir at the younger ages when volatile delivery to planets is most likely to occur. We here present the detection of CO J=2-1 emission colocated with dust emission from the cometary belt in the 440 Myr old Fomalhaut system. Through spectrospatial filtering, we achieve a 5.4s detection and determine that the ring's sky-projected rotation axis matches that of the star. The CO mass derived (0.65-42) x10(-7) M-circle plus is the lowest of any circumstellar disk detected to date and must be of exocometary origin. Using a steady-state model, we estimate the CO+ CO2 mass fraction of exocomets around Fomalhaut to be between 4.6% and 76%, consistent with solar system comets and the two other belts known to host exocometary gas. This is the first indication of a similarity in cometary compositions across planetary systems that may be linked to their formation scenario and is consistent with direct interstellar medium inheritance. In addition, we find tentative evidence that(49 +/- 27)% of the detected flux originates from a region near the eccentric belt's pericenter. If confirmed, the latter may be explained through a recent impact event or CO pericenter glow due to exocometary release within a steady-state collisional cascade. In the latter scenario, we show how the azimuthal dependence of the CO release rate leads to asymmetries in gas observations of eccentric exocometary belts.
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Beise, Jakob. "In-situ calibration device of firn properties for Askaryan neutrino detectors." Thesis, Uppsala universitet, Högenergifysik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-452702.
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Simulations have demonstrated that high-energy neutrinos (E > 1017 eV) are detected cost-efficiently via the Askaryan effect in ice, where a particle cascade induced by the neutrino interaction produces coherent radio emission that can be picked up by antennas installed below the surface. A good knowledge of the near surface ice (aka firn) properties is required to reconstruct the neutrino properties. In particular, a continuous monitoring of the snow accumulation (which changes the depth of the antennas) and the index-of-refraction profile are crucial for an accurate determination of the neutrino's direction and energy. 14 months of data of the ARIANNA detector on the Ross Ice Shelf, Antarctica, are presented where a prototype calibration system was successfully used to monitor the snow accumulation with unprecedented precision of 1 mm. Several algorithms to extract the time differences of direct and reflected (off the surface) signals (D'n'R time difference) from noisy data (including deep learning) are explored. This constitutes an in-situ test of the neutrino vertex distance reconstruction using the D'n'R technique which is needed to determine the neutrino energy. Additionally, an in-situ calibration system is proposed that extends the radio detector station with a radio emitter to continuously monitor the firn properties by measuring D'n'R time difference. In a simulation study the station layout is optimized and the achievable precision is quantified.
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Beise, Jakob. "Measurement of the snow accumulation in Antarctica with a neutrino radio detector and extension to the measurement of the index-of-refraction profile." Thesis, Uppsala universitet, Högenergifysik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-437647.
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High-energy neutrino physics offers a unique way to investigate the most violent phenomena in our universe. The detection of energies above E > 1017 eV is most efficient using the Askaryan effect, where a neutrino-induced particle shower produces coherent radio emission that is detectable with radio antennas. By using radio techniques large volumes can be covered with few stations at moderate cost exploiting the large attenuation length of radio in cold ice. Key to the reconstruction of the neutrino properties visa precise and continuous monitoring of the firn properties. In particular the snow accumulation (changing the absolute depth of the antennas thus the propagation path of the signal) and the index-of-refraction profile are crucial for the neutrino energy and direction reconstruction. This work presents an in-situ calibration design that acts as an detector extension by adding additional emitter antennas to the station design to continuously monitor the firn properties by measuring the direct and reflected signals (D’n’R). In a simulation study the optimal station layout is determined and the achievable precision is quantified. Furthermore 14 months of data from an ARIANNA station at the Ross Ice Shelf, Antarctica, are presented where a prototype of this calibration system has been successfully installed to monitor the snow accumulation with unprecedented precision of 1 mm. Several algorithms, including deep learning algorithms, to compute the D’n’R time difference from radio traces are considered.
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Idrisoglu, Alper. "Wireless Sensor System for Monitoring Sportsmen Exposed to Hazardous Concussions." Thesis, Blekinge Tekniska Högskola, Institutionen för tillämpad signalbehandling, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-18477.
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Sport-related Traumatic Brain injuries (TBI) are a major problem in ice hockey. Reports show that it occurs 160 concussion per 1000 hours of play time and 4.6% of head injuries leads to a concussion in Sweden. A system that can monitor the players in real time and indicate an impact can contribute to better understanding the biomechanical etiology of a concussion. Purpose of this project is to test the ability of a wireless sensor network for monitoring the g-Forces that affect the head of the ice hockey players in real-time. We build a wireless sensor network system called g-Force Monitoring System (GFMS) by implementing a Web Socket connection between the sensor nodes and the server. The sensor measures and transmits the data over the Web Socket protocol to the server and the server registers and allows monitoring of the g-Force values in real-time. We achieved a 6 ms sampling rate by using the g-Force Monitoring System. The system was able to operate during one hour play time without any significant problem. The stored data shows that the GFMS has an ability to indicate impact and its duration over a predefined threshold. The user of the system can monitor the g-Force data in real time or can do analyzes on stored values. The GFMS can deliver valuable indications. If the system can come to existence and be implemented into the ice hockey helmets, by letting medical experts to look at and analyze the g-Force data, it can decrease the diagnosis and recovery time of a concussion. It can help to make the Ice hockey arena to a safer place without having to change the rhythm of the game.
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Vallot, Dorothée. "Modelling calving and sliding of Svalbard outlet glaciers : Spatio-temporal changes and interactions." Doctoral thesis, Uppsala universitet, Luft-, vatten och landskapslära, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-334787.
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Future sea level rise associated to global warming is one of the greatest societal and environmental challenges of tomorrow. A large part of the contribution comes from glaciers and ice sheets discharging ice and meltwater into the ocean and the recent worldwide increase is worrying. Future predictions of sea level rise try to encompass the complex processes of ice dynamics through glacier modelling but there are still large uncertainties due to the lack of observations or too coarse parameterisation, particularly for processes occurring at the glacier interfaces with the bed (sliding) and with the ocean (calving). This thesis focuses on modelling these processes from two marine-terminating glaciers in Svalbard, Kronebreen and Tunabreen. By inverting three years of high temporal resolution time-series of surface velocities on Kronebreen, basal properties are retrieved with the ice flow model Elmer/Ice in Paper I. Results suggest that surface melt during the summer greatly influences the dynamics of the following season and that sliding laws for such glaciers should be adapted to local and global processes changing in space and time. The subglacial drainage system, fed by the surface melt, is modelled in Paper II during two melting seasons. Results show different configurations of efficient and inefficient drainage systems between years and the importance of using a sliding law dependent on spatio-temporal changes in effective pressure. The interaction with the ocean is incorporated in Paper III by combining a series of models, including an ice flow model, a plume model and a particle model for discrete calving and compares the output with observations. Results show the importance of glacier geometry, sliding and undercutting on calving rate and location. However, more observations and analytic methods are needed. Time-lapse imagery placed in front of Tunabreen have been deployed and a method of automatic detection for iceberg calving is presented in Paper IV. Results show the influence of the rising plume in calving and the front destabilisation of the local neighbourhood.
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Oliveira, Fernando Luiz Pereira de. "Nonparametric intensity bounds for the detection and delineation of spatial clusters." Universidade Federal de Minas Gerais, 2011. http://hdl.handle.net/1843/ICED-8GQJAE.
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There is considerable uncertainty in the disease rate estimation for aggregated area maps, especially for small population areas. As a consequence the delineation of local clustering is subject to substantial variation. Consider the most likely disease cluster produced by any given method, like SaTScan Kulldorff [2006], for the detection and inference of spatial clusters in a map divided into areas; if this cluster is found to be statistically signifcant, what could be said of the external areas adjacent to the cluster? Do we have enough information to exclude them from a health program of prevention? Do all the areas inside the cluster have the same importance from a practitioner perspective? We propose a criterion to measure the plausibility of each area being part of a possible localized anomaly in the map. In this work we assess the problem of finding error bounds for the delineation of spatial clusters in maps of areas with known populations and observed number of cases. A given map with the vector of real data (the number of observed cases for each area) shall be considered as just one of the possible realizations of the random variable vector with an unknown expected number of cases. In our methodology we perform m Monte Carlo replications: we consider that the simulated number of cases for each area is the realization of a random variable with average equal to the observed number of cases of the original map. Then the most likely cluster for each replicated map is detected and the corresponding m likelihood values obtained by means of the m replications are ranked. For each area, we determine the maximum likelihood value obtained among the most likely clusters containing that area. Thus, we construct the intensity function associated to each area's ranking of its respective likelihood value among the m obtained values. The method is tested in numerical simulations and applied for three different real data maps for sharply and diffusely delineated clusters. The intensity bounds found by the method re ect the geographic dispersion of the detected clusters. The proposed technique is able to detect irregularly shaped and multiple clusters, making use of simple tools like the circular scan. Intensity bounds for the delineation of spatial clusters are obtained and indicate the plausibility of each area belonging to the real cluster. This tool employs simple mathematical concepts and interpreting the intensity function is very intuitive in terms of the importance of each area in delineating the possible anomalies of the map of rates. The Monte Carlo simulation requires an effort similar to the circular scan algorithm, and therefore it is quite fast. We hope that this tool should be useful in public health decision making of which areas should be prioritized.texto completo
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Van, Liefferinge Brice. "Thermal state uncertainty assessment of glaciers and ice sheets: Detecting promising Oldest Ice sites in Antarctica." Doctoral thesis, Universite Libre de Bruxelles, 2018. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/268026.
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In a warming world, glaciers and ice sheets have an increasingly large influence on the environment, particularly through their contribution to sea level rise. Their response to anthropogenic climate change, in addition to natural variability, has a critical impact on dependent populations and will be key to predict future climates. Understanding the past natural transitions is also important as if the natural variability of the climate system is not well understood, we stand little change of accurately predicting future climate changes, especially in the context of rapid global warming. Ice cores represent the best time capsules for the recovery of paleo-climate informations. For that, the recovery of a suitable 1.5 million-year-old ice core in Antarctica is fundamental to better understand the natural climate reorganisation which occurred between 0.9 and 1.2 Ma. Constraining the englacial and basal temperature evolution of glaciers and ice sheets through time is the first step in understanding their temporal stability and therefore potential impacts on climate. Furthermore, obtaining the best constraints on basal conditions is essential as such million-year-old ice will be located very near to the bedrock, where the thermal regime has the strongest impact. However, measurements of current englacial and basal temperature have only been obtained at a few drill sites for glaciers and ice sheets. We must therefore turn to thermodynamical models to provide theoretical and statistical constraints on governing thermal processes. Thermodynamical models rely on a suite of governing equations, which we describe in this thesis. Our first study area is the McCall glacier, in Alaska (USA), where we show that the glacier cooled down in the warming climate of the last 50 years using a 1D thermodynamical model. We calculate the present-day englacial temperature distribution using recently acquired data in the form of englacial temperature measurements and radio-echo sounding surveys of the glacier. We show the important of absence of latent heat release due to the refreezing of meltwater inside an active surface layer and reconstruct the last 50 years of equilibrium line altitude (ELA) elevation changes. In the context of Beyond Epica Oldest Ice, a European project aimed at recovering a 1.5 million year-old ice core, we propose for the first time a map of the location of adequate drilling sites for the entire Antarctic Ice Sheet. We use a 3D thermomechanical model to calculate a new basal temperature map of the Antarctic Ice Sheet, as well as a 1D thermodynamical model to constrain the poorly known geothermal heat flux (GHF). These combined model runs use the latest acquired data sets for the GHF, ice flow velocity, ice thickness and subglacial lakes. In order to take into account 2 Ma of Antarctic climate history, we use a transient 1D thermodynamical model to provide constraints on GHF by calculating the maximum value of GHF allowed to keep frozen basal conditions everywhere underneath the ice sheet. These values are then statistically compared to published GHF data sets to propose a probabilistic map of frozen and thawed bedrock locations. This transient model uses high spatial resolution radar data acquired over the Dome Fuji and Dome C regions to examine their likelihood of having preserved 1.5-million-year ice. We define a number of important criteria such as GHF, bedrock variability, ice thickness and other parameter values for Oldest Ice survival. We anticipate that our methods will be highly relevant for Oldest Ice prospection in other areas of the ice sheet that so far remain little or un-surveyed, as well as for the thermal modelling of other glaciers and ice sheets, and in particular, of the Greenland Ice Sheet.Doctorat en Sciences
info:eu-repo/semantics/nonPublished
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Nicolet, Mathieu. "Characterization of ice crystals and water droplets with the ice optical detector device (IODE) using depolarization measurements /." Zürich : ETH, 2008. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=17659.
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Mengesha, T. (Tewodros). "ICT-based bracelet for early detection of depression." Master's thesis, University of Oulu, 2016. http://urn.fi/URN:NBN:fi:oulu-201605221847.
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Information communication technology (ICT) has opened a door for different sectors to benefit from ICT by using its potential tools. Health industry is one sector benefiting from ICT solutions for improving service quality and productivity. By using ICT as a tool, this study raised one of the major social and health concern, depression also known as depressive disorder. The aim of this study was to find the potential ICT based solution for an early detection and monitoring of depression.
Individuals go through different phases of life for instance psychological trauma, sadness, sorrow, grief, unemployment and so on. The different life aspects lead individuals to depression and majority of us are not all fully aware of it. Time to time everyone feels down and gets the blues in reaction to frustration or a disturbing event which lasts a day or two. On the other hand, can last a lifetime and the illness is much more disabling. Blues has never been a cause for suicide but depression is.
The society we live in and the social norms we follow can have an impact to some sort of depression. It is not intentional but unnoticed small acts in our daily life routine can contribute to depression too. To treat depression many practice therapy and/or medical treatments. Depending on the stage of depression some get cured, some still suffer, and some commit suicide. In addition to that, depression is risk factor for coronary artery disease, cardiovascular disease and stroke. It has been proved and witnessed that depressed individuals respond better to treatment at early stage of depression.
By applying design science research (DSR) methodology as an approach, the ultimate goal of this study was to find optimal ICT based solution that can be used to monitor depression at early stage. Literature review was used to gather earlier knowledge on wearable technology and depression itself. While conducting the research, senior citizens are on focus as they are more prone to depression than younger generations.
Criteria-based self-assessment questionnaire and interview are the methods used by physicians to diagnose depression and its stage. This trend is susceptible to misinterpretation and inaccuracy as the diagnosis often depends on patient’s subjective understanding of depression. Based on earlier knowledge, depression types and symptoms are listed on this study. From the major symptoms of depression; loss of interest in activity, stress and insomnia can be monitored using wrist worn device. As an artefact this thesis sets requirements for wearable device that can monitor heart rate, individual’s activity and sleep patterns. The collected data from the wearable device are physical and physiological data set, which can further be used as an additional input by physicians to determine the existence of depression and its current stage. This data input also helps in reducing the risk of misinterpreting diagnosis.
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Komarov, Alexander. "New methods for detecting dynamic and thermodynamic characteristics of sea ice from radar remote sensing." Institute of Electrical and Electronics Engineers, 2014. http://hdl.handle.net/1993/30225.
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This dissertation presents new methods for detecting dynamic and thermodynamic characteristics of Arctic sea ice using radar remote sensing.
A new technique for sea ice motion detection from sequential satellite synthetic aperture radar (SAR) images was developed and thoroughly validated. The accuracy of the system is 0.43 km obtained from a comparison between SAR-derived ice motion vectors and in-situ sea ice beacon trajectories. For the first time, we evaluated ice motion tracking results derived from co-polarization (HH) and cross-polarization (HV) channels of RADARSAT-2 ScanSAR imagery and formulated a condition where the HV channel is more reliable than the HH channel for ice motion tracking. Sea ice motion is substantially controlled by surface winds. Two new models for ocean surface wind speed retrieval from C-band SAR data have been developed and validated based on a large body of statistics on buoy observations collocated and coincided with RADARSAT-1 and -2 ScanSAR images. The proposed models without wind direction input demonstrated a better accuracy than conventionally used algorithms. As a combination of the developed methods we designed a wind speed-ice motion product which can be a useful tool for studying sea ice dynamics processes in the marginal ice zone.
To effectively asses the thermodynamic properties of sea ice advanced tools for modeling electromagnetic (EM) wave scattering from rough natural surfaces are required. In this dissertation we present a new analytical formulation for EM wave scattering from rough boundaries interfacing inhomogeneous media based on the first-order approximation of the small perturbation method. Available solutions in the literature represent special cases of our general solution. The developed scattering theory was applied to experimental data collected at three stations (with different snow thicknesses) in the Beaufort Sea from the research icebreaker Amundsen during the Circumpolar Flaw Lead system study. Good agreement between the model and experimental data were observed for all three case studies. Both model and experimental radar backscatter coefficients were considerably higher for thin snow cover (4 cm) compared to the thick snow cover case (16 cm). Our findings suggest that, winter snow thickness retrieval may be possible from radar observations under particular scattering conditions.
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Martinez, Mari-José. "Design and testing of an infrared ice detector system for helicopter blades." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/10510.
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Dettman, Joshua R. "Experimental Measurements and Modeling to Understand Sensitivity and Plasma Sample Loading in Inductively Coupled Plasma Optical Emission Spectrometry." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1325279039.
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Wintergerst, Mieke. "Detection of inositol phosphates with HPLC-ICP-AES : Method development." Thesis, Uppsala universitet, Analytisk kemi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-202003.
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Inositol phosphates (IPs) represent a major part of the organic phosphorus found in the environment, which makes their identification and quantification very important. The goal of this project was to explore the possibility of quantification of IPs with inductively coupled plasma - atomic emission spectrometry (ICP - AES). This paper deals with the creation of an in-house IP standard and the considerations for the successful linking of high performance liquid chromatography (HPLC) with ICP - AES. Experiments with different nebulizers, mobile phases, standard solutions and model substance were performed. The proposed optimal conditions for the ICP experiments are: the use of a modified Lichte nebulizer, mobile phase without methanol and the use of standards matched to the mobile phase. Adenosine monophosphate (AMP) was found to be a good model substance and showed that the band broadening from HPLC to ICP – AES was approximately a factor of 2. Limits of detection for AMP were 5 µM for HPLC and 20 µM for ICP – AES. The optimal way to create an in-house standard was using the potassium salt of IP6 and treating it for 90 minutes at a temperature of 120 ºC with 3.2 M acetic acid.
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Cakici, Baki. "The Informed Gaze : On the Implications of ICT-Based Surveillance." Doctoral thesis, Stockholms universitet, Institutionen för data- och systemvetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-92956.
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Information and communication technologies are not value-neutral. I examine two domains, public health surveillance and sustainability, in five papers covering: (i) the design and development of a software package for computer-assisted outbreak detection; (ii) a workflow for using simulation models to provide policy advice and a list of challenges for its practice; (iii) an analysis of design documents from three smart home projects presenting intersecting visions of sustainability; (iv) an analysis of EU-financed projects dealing with sustainability and ICT; (v) an analysis of the consequences of design choices when creating surveillance technologies. My contributions include three empirical studies of surveillance discourses where I identify the forms of action that are privileged and the values that are embedded into them. In these discourses, the presence of ICT entails increased surveillance, privileging technological expertise, and prioritising centralised forms of knowledge.At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Manuscript. Paper 5: Manuscript.
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Monzer, Mohamad-Houssein. "Model-based IDS design pour ICS." Thesis, Université Grenoble Alpes, 2020. http://www.theses.fr/2020GRALT056.
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Les systèmes industriels présentent des risques de sécurité liés à leurs vulnérabilités informatiques. Ces systèmes, répartis dans le monde, continuent d'être la cible d'attaques. Bien que les systèmes industriels partagent des vulnérabilités communes avec les systèmes informatiques, ils ont tendance à avoir plus de contraintes en raison de l'interaction entre les systèmes cyber et physiques.Les systèmes de détection d'intrusion donnent une visibilité au système et sont considérés comme l'une des solutions pour détecter les attaques ciblées. Il semble donc pertinent de s'appuyer sur un modèle physique du système cyber-physique pour obtenir un système de détection d'intrusion (IDS) pour les systèmes industriels. La plupart des IDS sont basés sur des règles qui définissent comment les attaques possibles sont détectées. Ces règles sont généralement utilisées pour décrire les scénarios d'attaque possibles sur les systèmes ou pour décrire le comportement normal du système. Cependant, la création et la maintenance manuels des règles pour un système complexe peuvent s'avérer être une tâche très difficile.Cette thèse propose une solution pour modéliser ICS et concevoir des IDS spécifiques pour les systèmes industriels. Un générateur de règles IDS basé sur un modèle est encore proposé, qui convertit un modèle de système en règles IDS basées sur des anomalies. Enfin, l'efficacité des règles générées est évaluéeIndustrial systems present security risks related to their IT vulnerabilities. These systems, spread over the world, continue to be targets of attacks. While Industrial systems share common vulnerabilities with IT systems, they tend to have more constraints due to the interaction between cyber and physical systems.Intrusion detection systems give visibility to the system and are considered as one of the solutions to detect targeting attacks. Hence, it seems relevant to rely on a physical model of the cyber-physical system to obtain an intrusion detection system (IDS) for industrial systems. Most IDSs are based on rules that define how possible attacks are detected. These rules are generally used to either describe possible attack scenarios on the systems or used to describe the normal system behavior of the system. However, manually creating and maintaining rules for a complex system can prove to be a very tedious and difficult task.This thesis proposes a solution to model ICS and to design specific IDS for industrial systems. A model-based IDS rule generator is also proposed, which converts a system model into anomaly-based IDS rules. Finally, the effectiveness of the generated rules is evaluated
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Kouchinsky, Alan J. "Determination of smoke algoritm [i.e. algorithm] activation for video image detection." College Park, Md.: University of Maryland, 2007. http://hdl.handle.net/1903/7223.
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Thesis (M.S.) -- University of Maryland, College Park, 2007.Thesis research directed by: Dept of Fire Protection Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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CASELLI, SERENA. "Fall risk detection and prediction in community-dwelling older adults." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2021. http://hdl.handle.net/10281/306605.
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Il rischio di caduta (RdC) e una lesione correlata aumentano con l'età e con l'associazione di patologie neurologiche. Le cadute sono un evento temibile per le conseguenze traumatiche e psicologiche, il loro costo sta diventando insostenibile e la loro prevenzione negli anziani è una priorità di sanità pubblica. Le linee guida internazionali raccomandano la rimozione dei fattori di RdC modificabili e l'attuazione di interventi efficaci. Tuttavia, non sono state utilizzate classificazioni univoche dei fattori di RdC, quindi l'uso delle Classificazioni Internazionali dell'OMS come riferimento universale può essere la soluzione più logica e naturale. Lo screening del RdC è la prima componente di programmi di prevenzione delle cadute efficaci. Ad oggi, nonostante l'utilizzo di numerosi strumenti di valutazione, non è possibile rilevare e prevedere il RdC con un’accuratezza diagnostica ottimale.
Gli obiettivi della tesi sono stati: 1) validare un algoritmo di screening seriale del RdC con alta accuratezza diagnostica in un campione di anziani in comunità, anche con PD e ictus, nella predizione di una, due e tre cadute nei successivi dodici mesi; 2a) valutare l'effetto delle patologie neurologiche sui test di screening; 2b) validare un core set ICD&ICF per il RdC nella stessa popolazione.
Utilizzando i dati raccolti nello studio PRE.C.I.S.A., abbiamo eseguito le seguenti analisi: 1) per validare un algoritmo di screening seriale abbiamo calibrato le scale VAE, VOE1 e VOE2 con tecniche classiche e Rasch analysis, calcolato i due FRAT-up e studiato l’accuratezza diagnostica degli strumenti e degli algoritmi di screening, ottenuti con combinazioni seriali delle scale e dei due FRAT-up e con modelli di regressione logistica, nella predizione degli outcome descritti; abbiamo confrontato le loro proprietà per validazione esterna; 2a) per valutare l'effetto delle patologie neurologiche sui test abbiamo condotto l’analisi del Differential Item Functioning (DIF) per le scale e il t-test per i due FRAT-up; 2b) per validare il core set ICD&ICF abbiamo revisionato i fattori di RdC e linkato alle categorie classificative.
Il campione disponibile dallo studio PRE.C.I.S.A. è stato di 768 anziani (femmine 65.3%; età media 75.8). Partendo da 29 variabili, abbiamo calibrato tre scale di misurazione (VAE, VOE1 e VOE), che hanno mostrato un fit soddisfacente al Rasch model (χ213=43.4; p=0.080; χ212=17.5, p=0.130; χ26=32.9, p=0.040). La loro affidabilità (Person Separation Index=0.912; 0.900; 0.800) è stata adeguata per la misurazione individuale (VAE, VOE1) e di gruppo (VOE2). La combinazione seriale con ‘AND’ rule delle scale ha generato algoritmi seriali con buona accuratezza diagnostica nella predizione degli outcome descritti in anziani in comunità, anche con PD e ictus, sulla base di cutoff definiti con un metodo ‘ad hoc’, che ha considerato un costo maggiore dei falsi negativi rispetto ai falsi positivi (1 caduta: sensibilità (SE)=62.4%; specificità (SP)=71.0%; accuratezza diagnostica (AD)=0.672; 2 cadute: SE=72.8%; SP=63.2%; AD=0.657; 3 cadute: SE=79.3%; SP=60.0%; AD=0.629). Abbiamo calcolato le probabilità cumulative post-test delle scale combinate con performance migliori di quelle dei singoli strumenti e costruito algoritmi aggiuntivi, basati su modelli di regressione logistica, utilizzando una combinazione parallela. Abbiamo realizzato una validazione esterna attraverso il confronto con algoritmi costruiti con i FRAT-up. Abbiamo dimostrato, poi, la gestione con Rasch analysis dell'effetto delle malattie neurologiche sulle prestazioni dei test (VAE: splitting analysis per DIF da malattie neurologiche). Infine, abbiamo validato un core set ICD&ICF per il RdC negli anziani in comunità, anche con PD e ictus (103 fattori di RdC linkati a 74 categorie).
Sono auspicabili ulteriori studi multicentrici di validazione per replicare questi risultati.The fall risk (FR) and a related injury increase with age and with the association of neurological diseases (Parkinson’s Disease (PD) or stroke). Falls represent a fearsome event for an elderly for traumatic and psychological consequences, and costs are becoming unsustainable. Hence, fall prevention in elderly at risk is a public health priority. All international guidelines recommend removing the modifiable FR factors and implementing effective interventions on people at risk. Nevertheless, investigators have not used consistent classifications for FR factors, so using the WHO Family of International Classifications can be the more natural and logical solution to cover the lack of a universal reference framework. FR screening is the first component of effective fall prevention programs. To date, despite the use of numerous FR assessment tools, it is not possible to detect and predict elderly fallers with optimal diagnostic accuracy. The aims of the thesis were: 1) to validate a FR serial screening algorithm with high diagnostic accuracy in a sample of community-dwelling elderly, also with PD and stroke, in the prediction of at least one, two, and three falls in the following twelve months; 2a) to assess the neurological disease's effect on FR tests; 2b) to validate an ICD& ICF core set for FR in the same population. Using data collected in the PRE.C.I.S.A. trial on fall risk, we performed the following analyses: 1) to validate a FR screening algorithm we calibrated the VAE, VOE1 and VOE2 scales with classical and Rasch analysis and we calculated the two FRAT-up; we studied the diagnostic accuracy of single tools and screening algorithms, obtained with serial combinations of the scales and the two FRAT-up tools, and with logistic regression models, in the prediction of the described outcomes; we compared their properties for external validation; 2a) to assess neurological disease’s effect on the tools we conducted a Differential Item Functioning (DIF) analysis for the scales and a t-test for the two FRAT-up; 2b) to validate the core set we reviewed the FR factors and we linked them to classification categories. The available sample from the PRE.C.I.S.A. trial was constituted by 768 older adults (female 65.3%; mean age 75.8). From 29 observed variables, we calibrated three measurement scales (VAE, VOE1, and VOE), which showed a satisfactory fit to the Rasch model (χ213=43.4; p=0.080; χ212=17.5, p=0.130; χ26=32.9, p=0.040). Their reliability (Person Separation Index=0.912; 0.900; 0.800) was adequate for individual (VAE, VOE1) and group measurement (VOE2). The serial combination with ‘AND’ rule of the scales generated FR serial algorithms, with good diagnostic accuracy, in the prediction of the described outcomes in community-dwelling elderly, also with PD and stroke, based on cutoffs defined using an ‘ad hoc’ method, which considered a higher cost of false negatives compared to false positives (≥1 fall: sensitivity (SE)=62.4%; specificity (SP)=71.0%; diagnostic accuracy (DA)=0.672; ≥2 falls: SE=72.8%; SP=63.2%; DA=0.657; ≥3 falls: SE=79.3%; SP=60.0%; DA=0.629). We calculated cumulative post-test probabilities of the combined scales, which performed more effectively than single tools, and we constructed additional algorithms based on logistic regression models using a parallel combination. We realized an external validation through the comparison with FRAT-up algorithms. Then, we demonstrated the management with Rasch analysis of the neurological disease effect on tools performance (e.g., VAE scale: splitting analysis for DIF by neurological diseases). Finally, we validated an ICD&ICF core set for the FR in community-dwelling elderly, also with PD and stroke (103 FR factors linked to 74 categories). Further projects are desirable to replicate these findings in larger, multicenter validation studies.
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Moudgil, Rashmi. "A Statistical and Circuit Based Technique for Counterfeit Detection in Existing ICs." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/23177.
Full textAbstract:
Counterfeit Integrated Circuits (ICs) are previously used ICs that are resold as new. They have become a serious problem in modern electronic devices. They cause lower performance, reduced life span and even catastrophic failure of systems and platforms. To prevent counterfeiting and the associated revenue loss, there is need for non-invasive and inexpensive techniques to establish the authenticity of devices. We describe a technique to detect a counterfeit IC that does not have any special anti-counterfeiting mechanisms built-in prior to deployment. Our detection criterion is based on measuring path delays. The experiments show that a single path delay cannot directly reveal the age, as it is also greatly influenced by process variation and this could result in large error in classifying ICs as authentic or counterfeit. �Instead, we establish that the relationship between the delays of two or more paths is a great indicator for the age of device. The idea is to project ICs from different age groups onto the space of the path delays and train a trusted reference hyper-surface for each age group. Ideally, the hyper-surfaces do not overlap. In this way, an IC under test can be assigned to one hyper-surface based on the distance of its footprint with respect to these hyper-surfaces, thus predicting its age. In our simulations, we observe over 97% correct prediction of identifying an aged IC from a new IC.Master of Science
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Schmidt, Benita. "Detection and Characterisation of Nanoparticles using Inductively Coupled Plasma Mass Spectrometry." Doctoral thesis, Humboldt-Universität zu Berlin, 2019. http://dx.doi.org/10.18452/20162.
Full textAbstract:
In dieser Doktorarbeit wurde eine analytische Methode zur Charakterisierung metallischer Nanopartikel (NPs) entwickelt und die Methode bei der Untersuchung natürlicher Proben angewendet. Mit einem analytisches System bestehend aus einem Mikrotropfengenerator (microdroplet generator, MDG) zusammen mit einem pneumatischen Zerstäuber und einem induktiv gekoppeltem Plasma-Massenspektrometer (ICP-MS) konnte eine quantitative und qualitative Charakterisierung von NPs durchgeführt werden.
Der MDG wurde verwendet um die Kalibrierungsfunktion für die massenspektrometrische Quantifizierung der Metalle in den Nanopartikelproben, die über den pneumatischen Zerstäuber eingeführt wurden, einzurichten. Der Hauptvorteil dieser Anordnung besteht darin, dass mit dem MDG für jedes Metall Tropfen einer gewünschten Größe hergestellt werden können und eine 100 %-ige Transporteffizienz gegeben ist. Die eingeführte Masse korrelierte mit der Signalintensität von Nanopartikeln, so dass die mit dem MDG generierten Tropfen für die Kalibrierung verwendet werden konnten ohne dass Referenzmaterial erforderlich war. Die aufwändige und fehleranfällige Bestimmung der Effizienz eines Zerstäubers, die für die Bestimmung des Metallgehaltes von NPs mittels eines Einzelpartikel-ICP-MS (spICP-MS) erforderlich ist, konnte dadurch vermieden werden.
Unter Anwendung dieser dualen Einführungsmethode wurden Größen und Konzentrationen einer Reihe von Standard Silber (Ag) NPs und Referenz Gold (Au) NPs mit hoher Genauigkeit bestimmt.
Zusätzlich wurde mit einem neuen kommerziell verfügbaren ICP-Flugzeitmassenspektrometer (ICP-TOF-MS) Ag und Au NPs in unterschiedlichen Matrices charakterisiert: in verschiedenen Salzsäure (HCl)- und Salpetersäure (HNO3)- Konzentrationen und in Gegenwart verschiedener Elemente. Bei den unterschiedlichen Matrices war die Größenbestimmung innerhalb der gegebenen Standardabweichungen korrekt.In this doctoral thesis an analytical method for characterising metal nanoparticles (NPs) was developed and its application for investigating natural samples verified. An analytical system consisting of a microdroplet generator (MDG) used in combination with a pneumatic nebuliser (PN) and an inductively coupled plasma mass spectrometer (ICP-MS) proved capable of quantitatively and qualitatively identifying NPs. The MDG was used to establish the calibration function for mass quantification of the metal present in the sample NPs introduced via the PN. The major advantage of this configuration is that the MDG generated droplets of tailored size for any given metal while offering a 100 % transport efficiency. The introduced mass correlated with signal intensities of NPs and thus the microdroplet generated droplets could be used for calibration purposes without the need for any reference material. Thus, the tedious and error-prone nebuliser efficiency determination step that is required when determining the NP metal content using the single particle mode ICP-MS (spICP-MS) approach, could be avoided. With this dual sample introduction method, the sizes and concentrations of a range of standard silver (Ag) NPs and gold (Au) reference NPs were determined with high accuracy. Additionally, together with a new commercially available ICP-time of flight-MS (ICP-TOF-MS) the characterisation of Ag- and Au-NPs was carried out in various matrices: In hydrochloric (HCl) and nitric acid (HNO3) at a range of concentration and in different elemental environments. In the presence of matrices, it was found that the size characterisation of the NPs is correct within the standard deviation.
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Banga, Mainak. "Partition based Approaches for the Isolation and Detection of Embedded Trojans in ICs." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/34924.
Full textAbstract:
This thesis aims towards devising a non-destructive testing methodology for ICs fabricated
by a third party manufacturer to ensure the integrity of the chip. With the growing trend of
outsourcing, the sanity of the final product has emerged to be a prime concern for the end
user. This is especially so if the components are to be used in mission-critical applications
such as space-exploration, medical diagnosis and treatment, defense equipments such as
missiles etc., where a single failure can lead to a disaster. Thus, any extraneous parts
(Trojans) that might have been implanted by the third party manufacturer with a malicious
intent during the fabrication process must be diagnosed before the component is put to use.
The inherent stealthy nature of Trojans makes it difficult to detect them at normal IC outputs. More so, with the restriction that one cannot visually inspect the internals of an IC after it has been manufactured. This obviates the use of side-channel signal(s) that acts like a signature of the IC as a means to assess its internal behavior under operational conditions.
In this work, we have selected power as the side-channel signal to characterize the internal
behavior of the ICs. We have used two circuit partitioning based approaches for isolating and
enhancing the behavioral difference between parts of a genuine IC and one with a sequence
detector Trojan in it. Experimental results reveal that these approaches are effective in
exposing anomalous behavior between the targeted ICs. This is reflected as difference in
power-profiles of the genuine and maligned ICs that is magnified above the process variation
ensuring that the discrepancies are observable.
Master of Science
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Yordán, López Fernando A. "Point cloud alignment in arm reconstruction for lymphedema detection by iterating pairwise ICP." Thesis, Massachusetts Institute of Technology, 2018. https://hdl.handle.net/1721.1/121644.
Full textAbstract:
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2018
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 59-62).
Arm lymphedema is a debilitating condition characterized by a large swelling of the patient arms. This thesis describes a system for measuring arm volume with the goal of providing a cost-effective, reliable, easy to use, comfortable, and informative alternative to the tedious water displacement method or the expensive perometer. The device consists of 8 inexpensive positionally fixed realsense sr300 depth cameras in a frame that can be placed on a flat surface, and used to scan a patient's arm in order to build a 3D mesh that can be used to extract not only the total volume of the arm but also the volume of specific segments. A special focus is given to the method of global registration of each camera's depth image, where camera positions are iteratively adjusted by applying ICP between one camera's point cloud and the point cloud generated by all-but-that-one camera. The system is then validated by taking a set of measurements of a human arm and comparing the values against those obtained from the water displacement method, in addition to also measuring objects of known volume and comparing those values with the ground truth. Despite a large non constant percentage error between expected and obtained values, early experiments show an 5_ correlation value of .99 between the expected and measured volumes. While additional work and experiments are needed to guarantee the reliability of this proposed method in order to be used in a clinical setting, these early findings show the potential of using such a system in small clinics where both space and money limits the accessibility of a large or expensive device. Keywords: lymphedema, global registration, realsense, point cloud alignment, volume measurement, 3D reconstruction
by Fernando A. Yordán López.
M. Eng.
M.Eng. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science
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Hussian, Mohamed. "Monotonic and Semiparametric Regression for the Detection of Trends in Environmental Quality Data." Doctoral thesis, Linköping : Dept. of Mathematics, Univ, 2005. http://www.bibl.liu.se/liupubl/disp/disp2005/stat7s.pdf.
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Sarah, Bouckoms. "Time distribution analysis for flasher data and simulations in the IceCube neutrino detector." Thesis, University of Canterbury. Physics and Astronomy, 2011. http://hdl.handle.net/10092/9659.
Full textAbstract:
The IceCube neutrino observatory is located in the deep glacial ice below the South Pole. IceCube
consists of over 5, 000 photomultiplier tubes regularly spaced throughout a cubic kilometre volume
of ice. The photomultiplier tubes are receptive to the light produced by high energy neutrino
interactions. As a means of evaluating our understanding of the physics of light propagation, a
comparison was made between the data taken from artificial light sources and Monte Carlo
simulations of these events. The evaluation was done by comparing the shape of the light
arrival-time distributions. The three icemodels compared were the Additionally Heterogeneous
Absorption (AHA), South Pole Ice - 1 (Spice) and South Pole Ice - Mie (Spice Mie). The artificial
light sources used are LEDs, known as flashers, located within each of the detector modules. The
data set used in this study was taken on string 63 with single- photoelectron settings (one LED).
Various orientations of the flashing LED and relative position of the light source in the detector,
were studied over 15 depths in instrumented ice. Through a χ2 comparison and distribution
characteristics it was found that for the majority of cases, simulations which used the
Spice Mie ice model matched the data best. There were, however, some isolated cases in which
simulations using the Spice 1 or AHA ice models matched the flasher data best.
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Myers, David. "Detecting cyber attacks on industrial control systems using process mining." Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/130799/1/David_Myers_Thesis.pdf.
Full textAbstract:
Industrial control systems conduct processes which are core to our lives, from the generation, transmission, and distribution of power, to the treatment and supply of water. These industrial control systems are moving from dedicated, serial-based communications to switched and routed corporate networks to facilitate the monitoring and management of an industrial processes. However, this connection to corporate networks can expose industrial control systems to the Internet, placing them at risk of cyber-attack. In this study, we develop and evaluate a process-mining based anomaly detection system to generate process models of, and detect cyber-attacks on, industrial control system processes and devices.
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Kabir-Querrec, Maëlle. "Cyber sécurité des systèmes industriels pour les smart-grids : détection d'intrusion dans les réseaux de communication IEC 61850." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAT032/document.
Full textAbstract:
Les systèmes de contrôle et d'automatisation industriels (IACS - Industrial Control and Automation Systems) reposent largement et de plus en plus sur les Technologies de l'Information et de la Communication. A l'origine, les IACS utilisaient des protocoles propriétaires sur des réseaux fermés, assurant ainsi une sécurité par obscurité et isolement. Mais les technologies et les usages ont évolué et cette sécurité intrinsèque n'existe plus désormais. Cette évolution concerne entre autre le domaine électrique : le réseau électrique devenant le "smart grid".Le standard IEC 61850 est un pilier pour le développement du smart grid. Il a pour objectif de rendre possible l'interopérabilité dans les "Systèmes et réseaux de communication pour l'automatisation des services de distribution d'énergie". Pour cela, la norme définit un modèle de données commun ainsi qu'une pile de protocoles répondant à divers besoins de communication.Le standard IEC 61850 n'aborde pas la question de la cyber sécurité malgré une prise de conscience générale qu'un risque cyber pèse sur les IACS.Ces travaux de recherche proposent de répondre à cette question de la cyber sécurité par de la détection d'intrusion dans les réseaux IEC 61850, et plus précisément dans les communications temps-réel GOOSE. L'idée est d'exploiter au maximum les sources d'informations que sont les spécifications du protocole et la configuration du système pour développer un système de détection d'intrusion réseau (NIDS - Network Intrusion Detection System) sur mesure. Cette approche comportementale déterministe est un gage de précision de détection.Ce manuscrit compte quatre chapitres. Les deux premiers consistent en un état de l'art détaillé sur les NIDS pour les IACS d'une part, et l'analyse du risque cyber d'autre part. Les deux autres chapitres présentent les contributions proprement dites de ces travaux de thèse. Le chapitre 3 explore tout d'abord le risque cyber pesant sur un poste électrique et pouvant compromettre la sûreté de fonctionnement du système. Dans un deuxième temps, est proposée une extension du modèle de données IEC 61850 dédiées à la détection d'intrusion dans les communication GOOSE. Le chapitre 4 commence avec la démonstration expérimentale de la faisabilité d'une attaque de type injection de données sur le protocole GOOSE, puis explique comment utiliser les fichiers de configuration du système pour spécifier les règles de détection. Un analyseur syntaxique pour le protocole GOOSE a été intégré à l'analyseur de trafic open source Bro, permettant l'implémentation d'un algorithme de détectionInformation and Communication Technologies have been pervading Industrial Automation and Control Systems (IACS) for a few decades now. Initially, IACS ran proprietary protocols on closed networks, thus ensuring some level of security through obscurity and isolation. Technologies and usages have evolved and today this intrinsic security does not exist any longer, though. This transition is in progress in the electricity domain, the power infrastructure turning into the "smart grid".The IEC 61850 standard is key to the smart grid development. It is aimed at making interoperability possible in ``Communication networks and systems for power utility automation''. It thus defines a common data object model and a stack of protocols answering different purposes.Although the cyber risk in IACS is now widely acknowledged, IEC 61850 does not address cyber security in any way whatsoever.This work tackles the question of cyber security through network intrusion detection in IEC 61850 networks, and more specifically in real-time GOOSE communications. The idea is to get the most out of the protocol specifications and system configuration while developing a tailored NIDS. This enables detection accuracy
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Syed, Sarah Sabeena. "Correlation of nebulizer performance with basic aerosol properties, response and detection limits in ICP-AES." Thesis, Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/27661.
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Weiss, Steven Michael. "Induction and detection of ventricular arrhythmias by ICD and the influences of antiarrhythmic drug therapy." Thesis, The University of Sydney, 1994. https://hdl.handle.net/2123/26862.
Full textAbstract:
The development of implantable cardioverter-defibrillators (ICDs) has been associated with three major areas of concern - how to accurately and rapidly detect and diagnose the patient's cardiac rhythm, how to induce ventricular fibrillation for device testing post-implant, and what influence concomitant antiarrhythmic medication may have on ICD performance. This thesis examines these three areas of concern.
Studies were undertaken in dogs to determine whether the electrical impedance (2) measured across both ventricles using defibrillation patch electrodes was modulated (AZ) by ventricular contraction, and furthermore, whether the amplitude of AZ reflected changes in ventricular pumping performance. The results of the studies showed that AZ did reflect ventricular pumping when measured using either acutely or chronically implanted patches and moreover, that changes in AZ amplitude more accurately reflected the onset of electromechanical dissociation, spontaneous ventricular tachycardia and electrical alternans than did changes in cycle length - the parameter currently used by all ICD manufacturers for the detection of and discrimination between ventricular arrhythmias. This study also determined that AZ could be measured using very little energy from the battery of an ICD. Furthermore, since AZ can be measured from defibrillation patches, thus obviating the need for additional implantable hardware, it appears to be a promising indicator of ventricular pumping performance for use with ICDs.
Since the pacemaker circuitry within ICDs suffers from voltage droop during rapid pacing, an alternative technique to induce ventricular fibrillation for noninvasive ICD testing post-implant was evaluated. The technique, which involved the delivery of a train of low amplitude cardioversion or defibrillation shocks, was found to be effective when delivered to any of a variety of epicardial and non-thoracotomy defibrillation electrode combinations.
The effects of commonly used antiarrhythmic drugs on A2 and fibrillation induction, as well as on several other aspects of ICD operation, was assessed in anaesthetised cross-breed dogs. AZ was shown to reflect the changes in ventricular pumping following quinidine, lignocaine and sotalol dosing more appropriately than cycle length. Furthermore, AZ was more appropriate than arterial pulse pressure in reflecting ventricular pumping following quinidine dosing. Although sotalol increased the energy required for fibrillation induction, fibrillation was always inducible.
This study showed that quinidine and sotalol significantly increased pacing thresholds. Since loss of pacing capture could lead to death in pacemakerdependent patients or those who require antitaohycardia pacing, pacing thresholds should be re-tested if a patient’s drug regimen is altered to include these drugs. In addition, lignocaine and verapamil significantly increased the voltages required for successful defibrillation and therefore, any ICD patient administered with either of these drugs should be re-tested for defibrillation efficacy. Since four of the six drugs tested increased the risk of death to ICD patients. it is advisable that pacing and defibrillation efficacy be re-tested in all ICD patients undergoing changes to their antiarrhythmic drug regimen.
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FREITAS, JOAO C. D. de. "Identificação de assinaturas químicas em resíduos de disparos de arma de fogo em diferentes alvos." reponame:Repositório Institucional do IPEN, 2010. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10023.
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Made available in DSpace on 2014-10-09T12:33:55Z (GMT). No. of bitstreams: 0Made available in DSpace on 2014-10-09T14:03:59Z (GMT). No. of bitstreams: 0
Dissertação (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Galvenius, Hugo. "Identifikation av icke-representativa svar i frågeundersökningar genom detektion av multivariata avvikare." Thesis, Uppsala universitet, Matematiska institutionen, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-219546.
Full textAbstract:
To United Minds, large-scale surveys are an important offering to clients, not least the public opinion poll Väljarbarometern. A risk associated with surveys is satisficing – sub-optimal response behaviour impairing the possibility of correctly describing the sampled population through its results. The purpose of this study is to – through the use of multivariate outlier detection methods - identify those observations assumed to be non-representative of the population. The possibility of categorizing responses generated through satisficing as outliers is investigated. With regards to the character of the Väljarbarometern dataset, three existing algorithms are adapted to detect these outliers. Also, a number of randomly generated observations are added to the data, by all algorithms correctly labelled as outliers. The resulting anomaly scores generated by each algorithm are compared, concluding the Otey algorithm as the most effective for the purpose, above all since it takes into account correlation between variables. A plausible cut-off value for outliers and separation between non-representative and representative outliers are discussed. The resulting recommendation is to handle observations labelled as outliers through respondent follow-up or if not possible, through downweighting, inversely proportional to the anomaly scores.