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DYNAMIC FAILURE OF POLYMER BONDED EXPLOSIVE SYSTEMS: FROM IDEALIZED SINGLE CRYSTAL TO VARIATIONS OF THE TRADITIONAL PARTICULATE REINFORCED COMPOSITEKerry Ann M Stirrup (16405512) 24 July 2023 (has links)
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<p>Polymer bonded explosives (PBX) are a particle reinforced composite containing a high solids loading of explosive particulates bound in a polymer matrix. Commercially produced energetic particulates contain some percentage of flaws in the form of contaminants, porosity, and preexisting fractures. Additional large-scale porosity within the composite is generated during PBX formulation. The introduction of novel additive manufacturing techniques to the energetics field alters the known composite structure and introduces a porosity variable that has not been fully characterized. Porosity collapse during deformation is believed to be a predominant mechanism for hotspot formation, which dominates shock initiation behaviors. These phenomena are difficult to experimentally characterize due to inherent small spectral and temporal scales, and as such numerical and computational models are relied upon to inform fundamental physics. Experimental characterization of the behaviors of energetic materials during deformation is necessary to better inform computational studies and improve our understanding of hotspot formation mechanisms. </p>
<p>This dissertation experimentally evaluates the high-rate deformation of porosity in individual explosive particulates and within the overall composite structure. This has included the development of a novel micromachining technique for pore generation in energetic single crystals using the focused ion beam (FIB), resulting in precise and controllable porosity generation that is easily reproducible in collaboration with computational studies. FIB was shown to be an effective pore generation technique, verified by assessing surface roughness and pore quality compared to contemporary manufacturing methods. Three experimental subsets are evaluated: surface cracks in HMX single crystals, polygonal pores in HMX single crystals, and large-scale porosity variations in mock vibration assisted print (VAP) produced composites of borosilicate glass beads and Sylgard 184® binder. A single stage light gas gun was used to impact the samples at 400 m/s and the impact event and resultant material response were observed in real time using x-ray phase contrast imaging (PCI). Machined surface cracks were shown to have negligible effect on the final fracture behaviors of HMX crystals. In polygonal pores fractures were shown to originate due to stress concentration during impact followed by otherwise expected brittle fracture behaviors. For wedge-like pores, the shockwave culminates on the front face of the pore and contributed to early fracture in some samples as well as a consistent open fracture opposite the impact along the shockwave direction in later stages of impact. For the blunt rectangular-like pores two differing behaviors were observed, wherein either the pore condensed and fracture at the pore was not seen during the impact event or large open fractures formed at the pore corners opposite the shockwave. The variance in response is attributed to the energy of fracture dissipating somewhere else in the material bulk, like the behaviors observed in the milled slot samples. Finally, additively manufactured PBX deformation behaviors were observed to be dominated by the collapse of the existing ordered porosity in the bulk which occurred at an increased rate relative to the bulk material compression. This resulted in a three-stage progression of deformation, consisting of a rapid collapse of large-scale ordered porosity, followed by the densification of the remaining features, and ultimately ending in compaction of the bulk as the impact projectile fully compressed the samples. Future work includes exploration of further FIB produced pore effects on dynamic fractures, evaluation of printed material deformation behaviors at additional rates, as well as application and evaluation of additional VAP printed material formulations. </p>
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Treatment Effect of Percutaneous Coronary Intervention in Dialysis Patients With ST-Elevation Myocardial InfarctionKawsara, Akram, Sulaiman, Samian, Mohamed, Mohamed, Paul, Timir K., Kashani, Kianoush B., Boobes, Khaled, Rihal, Charanjit S., Gulati, Rajiv, Mamas, Mamas A., Alkhouli, Mohamad 15 October 2021 (has links)
RATIONALE & OBJECTIVE: Patients receiving maintenance dialysis have higher mortality after primary percutaneous coronary intervention (pPCI) than patients not receiving dialysis. Whether pPCI confers a benefit to patients receiving dialysis that is similar to that which occurs in lower-risk groups remains unknown. We compared the effect of pPCI on in-hospital outcomes among patients hospitalized for ST-elevation myocardial infarction (STEMI) and receiving maintenance dialysis with the effect among patients hospitalized for STEMI but not receiving dialysis. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: We used the National Inpatient Sample (2016-2018) and included all adult hospitalizations with a primary diagnosis of STEMI. PREDICTORS: Primary exposure was PCI. Confounders included dialysis status, demographics, insurance, household income, comorbidities, and the elective nature of the admission. OUTCOME: In-hospital mortality, stroke, acute kidney injury, new dialysis requirement, vascular complications, gastrointestinal bleeding, blood transfusion, mechanical ventilation, palliative care, and discharge destination. ANALYTICAL APPROACH: The average treatment effect (ATE) of pPCI was estimated using propensity score matching independently within the group receiving dialysis and the group not receiving dialysis to explore whether the effect is modified by dialysis status. Additionally, the average marginal effect (AME) was calculated accounting for the clustering within hospitals. RESULTS: Among hospitalizations, 4,220 (1.07%) out of 413,500 were for patients receiving dialysis. The dialysis cohort was older (65.2 ± 12.2 vs 63.4 ± 13.1, P < 0.001), had a higher proportion of women (42.4% vs 30.6%, P < 0.001) and more comorbidities, and had a lower proportion of White patients (41.1% vs 71.7%, P < 0.001). Patients receiving dialysis were less likely to undergo angiography (73.1% vs 85.4%, P < 0.001) or pPCI (57.5% vs 79.8%, P < 0.001). Primary PCI was associated with lower mortality in patients receiving dialysis (15.7% vs 27.1%, P < 0.001) as well as in those who were not (5.0% vs 17.4%, P < 0.001). The ATE on mortality did not differ significantly (P interaction = 0.9) between patients receiving dialysis (-8.6% [95% CI, -15.6% to -1.6%], P = 0.02) and those who were not (-8.2% [95% CI, -8.8% to -7.5%], P < 0.001). The AME method showed similar results among patients receiving dialysis (-9.4% [95% CI, -14.8% to -4.0%], P < 0.001) and those who were not (-7.9% [95% CI, -8.5% to -7.4%], P < 0.001) (P interaction = 0.6). Both the ATE and AME were comparable for other in-hospital outcomes in both groups. LIMITATIONS: Administrative data, lack of pharmacotherapy and long-term outcome data, and residual confounding. CONCLUSIONS: Compared with conservative management, pPCI for STEMI was associated with comparable reductions in short-term mortality among patients irrespective of their receipt of maintenance dialysis.
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Cognitive Deficits in Cardiac Rehabilitation: A Comparison of Post-Bypass and Post-Angioplasty PatientsBui, Matthew January 2017 (has links)
Mild cognitive deficits that negatively impact self-management education-related outcomes may be present in a proportion of cardiac rehabilitation patients and the degree of impairment may vary by the type of coronary revascularization procedure. The purpose of this study was to compare cognitive function, as measured by the Montreal Cognitive Assessment (MoCA), between coronary artery bypass graft surgery (CABG) and percutaneous coronary intervention (PCI) patients, and to determine independent variables of MoCA score. In a cross-sectional study, 78 cardiac rehabilitation patients (CABG n = 38, PCI n = 40) completed the MoCA. Demographics were collected and disease burden was calculated using the age-adjusted Charlson Comorbidity Index (ACCI). Mild cognitive deficits (MoCA ≤26) were present in 55.3% CABG and 30.0% PCI patients. An independent Student’s t test showed that MoCA scores were significantly lower among CABG patients (mean = 24.5, SD = 3.3) compared to PCI patients (M = 26.7, SD = 2.7), t (76) = 3.15, p < 0.01. Descriptive analyses of cognitive domain scores indicated that deficits in short-term memory and language were present among CABG patients. Using a backward regression, coronary revascularization procedure (CABG vs. PCI) (p = 0.006) and disease burden (ACCI) (p = 0.015) remained significant, while heart failure diagnosis became non-significant and was removed from the model (F (2, 75) = 8.382, p < 0.001). The final model explained 16.1% of the total variance in MoCA score (adjusted R2 = 0.161). Results indicate that cognitive deficits were present in cardiac rehabilitation participants and associated with the type of coronary revascularization procedure, suggesting the need for formal cognitive screening and adaptation of education interventions in cardiac rehabilitation. A future prospective cohort study is required to establish temporality, and to measure education-related outcomes, such as health-related quality of life (HRQOL) and self-management. / Thesis / Master of Science (MSc) / Cardiac rehabilitation (CR) is a multifaceted program consisting of exercise and education that is essential to the care of post-coronary revascularization patients. While exercise has shown to improve health outcomes, education has demonstrated inconsistent effects. Since education has imposed cognitive demands, this discrepancy in outcomes may, in part, be due to cognitive deficits present in a proportion of program attendees: the degree of impairment may vary by type of coronary revascularization procedure prior to CR. This study compared cognitive function between two groups of coronary revascularization patients, post-coronary bypass surgery and post-coronary angioplasty, and determined independent variables for cognitive function. Results showed that coronary bypass surgery patients had significantly lower cognitive function than coronary angioplasty patients at program intake. Coronary bypass surgery and accumulated disease burden were weakly associated with decreased cognitive function. Cognitive screening and adapted education for patients with cognitive deficits should be considered to improve CR outcomes.
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Pressurized intraperitoneal aerosol chemotherapy (PIPAC) in patients with peritoneal surface malignancies (PSM): a prospective single-center registry studyEberth, Jonas Alexander 27 June 2024 (has links)
Malignome des Peritoneums (peritoneal surface malignancies, PSMs) treten als Mesotheliome oder Metastasen auf. Ihre Diagnose bedeutet häufig eine schlechtere Prognose als bei anderen Fernmetastasen. Die Standardtherapie in palliativer Intention ist in der Regel eine systemische Chemotherapie (sCHT).
Intraperitoneale Druck-Aerosol-Chemotherapie (Pressurized intraperitoneal aerosol chemotherapy, PIPAC) ist eine neue, palliative Behandlungsmöglichkeit für ausgewählte Personen mit PSMs. Das Prinzip der laparoskopischen Vernebelung von Chemotherapeutika soll die Bioverfügbarkeit im Vergleich zu und anderen intraabdominellen Applikationen erhöhen. Sie wird meist in Kombination mit sCHT eingesetzt und zielt darauf ab, die Symptom- und Asziteslast der Behandelten zu reduzieren.
Diese monozentrische, prospektive Registerstudie untersucht die Sicherheit, Durchführbarkeit und Wirksamkeit der PIPAC. Einschlusskriterien waren ein histologisch gesichertes PSM und eine positive Tumorboard-Entscheidung. Ausschlusskriterien waren extraperitoneale Fernmetastasen und ein Eastern Cooperative Oncology Group (ECOG) Performance Status größer als 2.
Vor jeder PIPAC wurde eine strukturierte Anamnese, eine körperliche Untersuchung, sowie eine ausführliche chirurgische und onkologische Aufklärung durchgeführt.
Die PIPAC-Prozeduren wurden laparoskopisch in Allgemeinanästhesie gemäß interner Standard Operating Procedure durchgeführt. Zunächst wurde Aszites aspiriert und quantifiziert. Anschließend wurde eine diagnostische Laparoskopie durchgeführt, der Zugang zum Abdomen als „access“ oder „non access“ beschrieben, sowie der peritoneale Adhäsionsindex (peritoneal adhesion index, PAI) nach Coccolini und der peritoneale Krebsindex (peritoneal cancer index, PCI) nach Sugarbaker erhoben. Sechs Peritonealbiopsien wurden standardisiert entnommen. Nach Präparation und Färbung mit Hämatoxylin und Eosin wurde die relative Tumormenge bestimmt.
Nacheinander wurden Cisplatin und Doxorubicin in einer an die Körperoberfläche angepassten Dosierung appliziert. Die Chemotherapeutika wurden mit einer Injektionspumpe bei 200 psi und mit einer Flussrate von 0,5 ml/min über einen Hochdruckschlauch zum Vernebler gefördert. Dieser wurde auf dem 12 mm Trokar befestigt und verteilte die Medikamente im Abdomen. Währenddessen befand sich das gesamte Operationspersonal im separaten Einleitungsraum. Die Applikation wurde über einen Fußschalter gesteuert und durch ein Sichtfenster überwacht. Über den Druck im Kapnoperitoneum konnte freiwerdendes Aerosol detektiert werden. Nach 30 min wurde das Aerosol analog zu Narkosegasen in die Krankenhausentlüftung abgeleitet. Anschließend wurden die Behandelten für einige Stunden im Aufwachraum überwacht und dann auf die Normalstation gebracht. Postoperative Komplikationen wurden nach der Clavien Dindo Klassifikation (CDC) dokumentiert.
Insgesamt wurden 108 Patient:innen (n = 55 Frauen, n = 53 Männer) mit einem medianen Alter von 60 Jahren (Interquartilsabstand [IQA] 53–69 Jahre) eingeschlossen. Sie wiesen Primärtumore verschiedener Entitätsgruppen auf: n = 41 (38 %) gastral, n = 26 (24 %) kolorektal, n = 9 (8 %) gynäkologisch und n = 15 (14 %) weitere (n = 7 Mesotheliome, n = 3 Pseudomyxoma peritonei, n = 5 Krebserkrankungen mit unbekanntem Primärtumor). Im Median wurden zwei PIPAC-Prozeduren pro Patient:in durchgeführt (IQA 1–3). Bei 12 Patient:innen wurde zuvor eine zytoreduktive Chirurgie (CRS) mit hyperthermer intraperitonealer Chemoperfusion (HIPEC) durchgeführt.
Von 230 geplanten PIPAC-Prozeduren konnten 189 durchgeführt werden. 41 Prozeduren mussten abgebrochen oder storniert werden: 9 Patient:innen zeigten bei der Aufnahmeuntersuchung einen verschlechterten Allgemeinzustand (z. B. neue Fernmetastasen im Computertomogramm). 3 Patient:innen aspirierten während der Narkoseeinleitung. Bei 7 Laparoskopien war makroskopisch kein PSM mehr nachweisbar. In 22 Fällen war das Abdomen nicht zugänglich (non-access) und/oder es kam zu Darmläsionen.
Bei der Aufnahmeuntersuchung vor jeder PIPAC-Prozedur wiesen die Patient:innen in den meisten Fällen keine der spezifisch erhobenen Symptome auf. 55 (24 %) klagten über Bauchschmerzen, 47 (21 %) über Übelkeit oder Erbrechen, 16 (7 %) über Obstipation und 4 (2 %) über Dysphagie (mehrere Symptome gleichzeitig möglich). Die folgenden prä- und perioperativ erhobenen Werte änderten sich nicht signifikant mit aufeinanderfolgenden PIPAC-Prozeduren pro Patient:in (Varianzanalyse [analysis of variance, ANOVA], p > 0,1): ECOG Performance Status (Median 1, IQA 0–1), American Society of Anesthesiologists Klassifikation (Median 3, IQA 2–3), nutritional risk screening (NRS) (Median 2, IQA 2–3), global health status der European Organization for Research and Treatment of Cancer (EORTC) (Median 50, IQA 33–67), Operationsdauer (Mittelwert 104 min, Standardfehler des Mittelwertes 1,5 min), PCI (Median 15, IQA 6–24), PAI (Median 4, IQA 0–12) und maximaler histologischer Tumoranteil (Median 24 %, IQA 5–60 %). Die ersten drei konsekutiven PIPAC-Prozeduren zeigten eine signifikante Reduktion des Aszitesvolumens (ANOVA, p = 0,016). Die mediane postoperative Liegedauer betrug 4 Tage (IQA 3 4 Tage). Bei 31 von 213 PIPAC-Prozeduren (14,6 %), bei denen die Patient:innen in den Operationstrakt gebracht worden waren, traten postoperative Komplikationen auf (10,8 % Grad II, 2,4 % Grad IV, 1,4 % Grad V nach CDC).
Insgesamt wurden 21 non access-Fälle (9,9 % der 213 PIPAC-Prozeduren, bei denen die Patient:innen in den Operationstrakt gebracht worden waren) und 14 intraoperative Komplikationen (6,6 %) dokumentiert. In den 21 non access-Situationen traten 8 Darmläsionen auf (n = 4 Serosaläsionen, n = 4 transmurale Perforationen). Postoperativ kam es bei den non access Fällen zu 4 Komplikationen Grad II nach CDC und keinen höhergradigen Komplikationen. Bei 3 weiteren Prozeduren traten Darmläsionen ohne non access auf (n = 1 Serosa, n = 2 transmural). Ein:e Patient:in verstarb nach Darmläsion mit nachfolgender Nahtinsuffizienz, Peritonitis und Sepsis. Bei 3 Narkoseeinleitungen aspirierten die Patient:innen und entwickelten daraufhin eine Pneumonie. Auf der Intensivstation wurde sofort eine kalkulierte Antibiotikatherapie eingeleitet. Dennoch verstarben 2 von 3 Patient:innen nach 3 bzw. 4 Tagen. Ein:e Patient:in konnte erfolgreich behandelt und nach 15 Tagen entlassen werden.
Aufgrund der hohen Inzidenz von non access und Darmläsionen wurde nach prädiktiven Markern gesucht. Patient:innen mit einer CRS mit HIPEC in der Vorgeschichte hatten ein signifikant erhöhtes Risiko für non access (Odds Ratio [OR] 5,9, χ², p < 0,01) und Darmläsionen (OR 6,4, χ², p < 0,01). Patient:innen mit mehr als zwei Voroperationen im Bauchraum wiesen ebenso ein signifikant erhöhtes Risiko für non-access (OR 4,9, χ², p < 0,01) und Darmläsionen (OR 4,9, χ², p = 0,01) auf.
Am Ende des Studienzeitraums befanden sich noch 6 Patient:innen in Therapie. Bei den Übrigen (bei denen mindestens eine PIPAC-Prozedur durchgeführt wurde) gab es unterschiedliche Gründe für die Beendigung der Therapie: n = 26 (34 %) verstorben, n = 20 (26 %) Progression der Grunderkrankung, n = 12 (16 %) Regression der Grunderkrankung (n = 7 ohne weitere Therapie, n = 5 anschließend CRS mit HIPEC), n = 6 (8 %) non-access, n = 5 (6 %) Patient:innenwunsch, n = 8 (10 %) kein Grund dokumentiert. Das mediane Gesamtüberleben ab der ersten geplanten PIPAC-Prozedur betrug 264 Tage (IQA 108–586).
Insgesamt stellt die PIPAC eine neuartige off-label-Therapie für Patient:innen mit PSMs dar, deren Wirksamkeit und Sicherheit untersucht werden muss. Sie sollte daher nur im Rahmen klinischer Studien durchgeführt werden. Die vorliegende Studie liefert eine genaue Dokumentation von Symptomen, Komplikationen und unerwünschten Ereignissen im Zusammenhang mit PIPAC.
In Zusammenschau der vorhandenen Studien scheint die PIPAC gut geeignet zu sein, PSMs und Lebensqualität zu stabilisieren. Zum Nachweis eines kausalen Effekts sind jedoch randomisierte, kontrollierte Studien nötig.:Einführung 1
Epidemiologie 1
Magenkarzinom 1
Kolorektales Karzinom 1
Ovarialkarzinom 1
Pankreaskarzinom 2
Mesotheliom 2
Pseudomyxoma peritonei 2
Pathophysiologie 2
Ablösung vitaler Krebszellen 2
Intraperitonealer Transport 3
Adhäsion und Invasion 3
Wachstum und Metastasierung 3
Symptome/Klinik 3
Diagnostik 3
Bildgebende Verfahren 3
Peritonealer Krebsindex 5
Peritonealer Adhäsionsindex 5
Therapie 5
Systemische Therapie 6
Zytoreduktive Chirurgie 6
Hypertherme intraperitoneale Chemoperfusion 6
Intraperitoneale Druck-Aerosol-Chemotherapie 7
Weitere Therapieoptionen 8
Zielsetzung 8
Publikation 9
Zusammenfassung 21
Literaturverzeichnis 24
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Modelagem e controle linear de um sistema de levitação de imã permanente. / Modeling and linear control of a permanent magnet levitation system.Botelho, Izaias José 08 February 2008 (has links)
O objetivo deste trabalho é apresentar um novo tipo de sistema de levitação baseado na força de interação magnética entre uma bobina de núcleo não-magnético e um imã permanente, em casos de simetria axial entre os dispositivos, nos moldes do problema 23 proposto no TEAM Workshop. Este tema é bastante atual e vários métodos têm sido estudados e propostos em razão da complexidade na determinação precisa das forças sobre os imãs permanentes imersos em um campo magnético em um circuito magnético aberto. O primeiro grande desafio deste trabalho é obter uma expressão analítica para esta força de interação magnética em casos de simetria axial usando o método de cargas magnéticas ligadas. Para tal, algumas hipóteses simplificadoras foram adotadas como considerar o campo magnético gerado pela bobina aproximadamente uniforme em toda a face do imã permanente e assumir que a magnetização do imã é constante e independente da variação de sua distância para a bobina. Pretende-se aproveitar o sistema implementado neste trabalho como bancada experimental no Laboratório de Controle da Universidade de São Paulo. Foi projetado um controlador PID através de ferramentas gráficas obedecendo a alguns critérios de desempenho, tanto no domínio do tempo como no domínio da freqüência. Uma vez sintonizado, foi utilizado o toolbox Real-Time Windows Target do Simulink e a placa de aquisição PCI 6221 (da National Instruments) para controlar em tempo real a planta de levitação em malha fechada. Os resultados experimentais foram muito satisfatórios de modo que o modelo analítico foi considerado válido. O sistema apresentou boas características como, por exemplo, um bom acompanhamento do sinal de referência, mesmo em grandes excursões, erro de regime nulo, levitação estável em distâncias relativamente grandes e uma boa estabilidade radial. O uso de dois sensores Hall mostrou-se eficiente na determinação da posição do imã permanente. / The objective of this work is to present a new kind of levitation system based on the interaction force between a non-magnetic core coil and a permanent magnet, in the case of axial symmetry between devices, as proposed by TEAM Workshop problem 23. This theme is very current and various methods have been studied and proposed in face of the complexity in determining precisely the force over permanent magnets immersed in a magnetic field in an open magnetic circuit. The first big challenge of this work is to obtain an analytical expression for this interaction magnetic force in the case of axial symmetry using the equivalent magnetic charge method. For this, some simplifying hypothesis have been adopted like considering the magnetic field created by the coil approximately uniform over all the permanent magnets face and assuming that magnets magnetization is constant and independent of the variation of its distance to the coil. The system implemented in this work is intended to be used as an experimental bench for the Laboratory of Control of Sao Paulo University. A PID controller was projected by means of graphical tools according to some criteria for performance, both in the field of time as in the frequency domain. Once tuned, the toolbox Real-Time Windows Target of Simulink and the PCI-6221 acquisition board (of National Instruments) were used to control in real time the levitation plant in closed loop. The experimental results were very satisfactory so that the analytical model was considered valid. The system showed good characteristics as, for instance, a good tracking of reference signal, even in large excursions of it, null stationary error, stable levitation at relatively big gaps and a good radial stability. The use of two Hall-effect sensors proved to be efficient in the determination of permanent magnets position.
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Novos ataques de canal secundário a dispositivos de entrada manual de dados confidenciais. / New side-channel attacks on devices for manual input of sensitive data.Faria, Gerson de Souza 09 December 2016 (has links)
Esta tese apresenta três novos ataques a equipamentos de pagamento eletrônico que possuem teclado mecânico, conhecidos como \"PIN pads\". Mostramos de três formas distintas como tais equipamentos possuem vulnerabilidades de segurança na camada física que permitem o vazamento do PIN (Personal Identification Number) quando o mesmo é digitado. Demonstramos experimentalmente que é possível inferir com elevada taxa de acerto (100% em um dos ataques) a senha digitada, de forma não-invasiva. Os ataques desenvolvidos são baseados na introdução de sensores nos próprios equipamentos ou em seu ambiente de operação: acelerômetros para análise de vibração, microfones para análise acústica e células de carga para medição de forças do pressionamento. Devido à massificação no uso de sensores por dispositivos de consumo, o roubo de informação por meios não convencionais é atividade crescente. Os resultados dos ataques de baixo custo realizados expõem sérias deficiências no processo de certificação de segurança de tais equipamentos. / This thesis presents three new attacks on electronic payment equipment having mechanical keypads, known as \"PIN pads\". We show in three different ways how they have security vulnerabilities at the physical layer allowing the leak of the PIN (Personal Identification Number) when it is entered. We experimentally demonstrated that it is possible to infer with high success rate (100% in one of the attacks) the password entered on the device, in a non-invasive way. The attacks are based on the placement of sensors inside the equipment itself or in its operating environment: accelerometers for doing vibration analysis, microphones for acoustic analysis and load cells for measuring the pressing force. Due to massive deployment of sensors in consumer devices, information theft by unconventional means is increasing. The results of the low-cost attacks here developed expose serious shortcomings in the process of security certification of such equipment.
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Novos ataques de canal secundário a dispositivos de entrada manual de dados confidenciais. / New side-channel attacks on devices for manual input of sensitive data.Gerson de Souza Faria 09 December 2016 (has links)
Esta tese apresenta três novos ataques a equipamentos de pagamento eletrônico que possuem teclado mecânico, conhecidos como \"PIN pads\". Mostramos de três formas distintas como tais equipamentos possuem vulnerabilidades de segurança na camada física que permitem o vazamento do PIN (Personal Identification Number) quando o mesmo é digitado. Demonstramos experimentalmente que é possível inferir com elevada taxa de acerto (100% em um dos ataques) a senha digitada, de forma não-invasiva. Os ataques desenvolvidos são baseados na introdução de sensores nos próprios equipamentos ou em seu ambiente de operação: acelerômetros para análise de vibração, microfones para análise acústica e células de carga para medição de forças do pressionamento. Devido à massificação no uso de sensores por dispositivos de consumo, o roubo de informação por meios não convencionais é atividade crescente. Os resultados dos ataques de baixo custo realizados expõem sérias deficiências no processo de certificação de segurança de tais equipamentos. / This thesis presents three new attacks on electronic payment equipment having mechanical keypads, known as \"PIN pads\". We show in three different ways how they have security vulnerabilities at the physical layer allowing the leak of the PIN (Personal Identification Number) when it is entered. We experimentally demonstrated that it is possible to infer with high success rate (100% in one of the attacks) the password entered on the device, in a non-invasive way. The attacks are based on the placement of sensors inside the equipment itself or in its operating environment: accelerometers for doing vibration analysis, microphones for acoustic analysis and load cells for measuring the pressing force. Due to massive deployment of sensors in consumer devices, information theft by unconventional means is increasing. The results of the low-cost attacks here developed expose serious shortcomings in the process of security certification of such equipment.
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Modelagem e controle linear de um sistema de levitação de imã permanente. / Modeling and linear control of a permanent magnet levitation system.Izaias José Botelho 08 February 2008 (has links)
O objetivo deste trabalho é apresentar um novo tipo de sistema de levitação baseado na força de interação magnética entre uma bobina de núcleo não-magnético e um imã permanente, em casos de simetria axial entre os dispositivos, nos moldes do problema 23 proposto no TEAM Workshop. Este tema é bastante atual e vários métodos têm sido estudados e propostos em razão da complexidade na determinação precisa das forças sobre os imãs permanentes imersos em um campo magnético em um circuito magnético aberto. O primeiro grande desafio deste trabalho é obter uma expressão analítica para esta força de interação magnética em casos de simetria axial usando o método de cargas magnéticas ligadas. Para tal, algumas hipóteses simplificadoras foram adotadas como considerar o campo magnético gerado pela bobina aproximadamente uniforme em toda a face do imã permanente e assumir que a magnetização do imã é constante e independente da variação de sua distância para a bobina. Pretende-se aproveitar o sistema implementado neste trabalho como bancada experimental no Laboratório de Controle da Universidade de São Paulo. Foi projetado um controlador PID através de ferramentas gráficas obedecendo a alguns critérios de desempenho, tanto no domínio do tempo como no domínio da freqüência. Uma vez sintonizado, foi utilizado o toolbox Real-Time Windows Target do Simulink e a placa de aquisição PCI 6221 (da National Instruments) para controlar em tempo real a planta de levitação em malha fechada. Os resultados experimentais foram muito satisfatórios de modo que o modelo analítico foi considerado válido. O sistema apresentou boas características como, por exemplo, um bom acompanhamento do sinal de referência, mesmo em grandes excursões, erro de regime nulo, levitação estável em distâncias relativamente grandes e uma boa estabilidade radial. O uso de dois sensores Hall mostrou-se eficiente na determinação da posição do imã permanente. / The objective of this work is to present a new kind of levitation system based on the interaction force between a non-magnetic core coil and a permanent magnet, in the case of axial symmetry between devices, as proposed by TEAM Workshop problem 23. This theme is very current and various methods have been studied and proposed in face of the complexity in determining precisely the force over permanent magnets immersed in a magnetic field in an open magnetic circuit. The first big challenge of this work is to obtain an analytical expression for this interaction magnetic force in the case of axial symmetry using the equivalent magnetic charge method. For this, some simplifying hypothesis have been adopted like considering the magnetic field created by the coil approximately uniform over all the permanent magnets face and assuming that magnets magnetization is constant and independent of the variation of its distance to the coil. The system implemented in this work is intended to be used as an experimental bench for the Laboratory of Control of Sao Paulo University. A PID controller was projected by means of graphical tools according to some criteria for performance, both in the field of time as in the frequency domain. Once tuned, the toolbox Real-Time Windows Target of Simulink and the PCI-6221 acquisition board (of National Instruments) were used to control in real time the levitation plant in closed loop. The experimental results were very satisfactory so that the analytical model was considered valid. The system showed good characteristics as, for instance, a good tracking of reference signal, even in large excursions of it, null stationary error, stable levitation at relatively big gaps and a good radial stability. The use of two Hall-effect sensors proved to be efficient in the determination of permanent magnets position.
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Datalogger pro sběrnici typu Profibus / Datalogger for ProfibusBráblík, Radim January 2010 (has links)
This thesis deals with creating application Datalogger for PROFIBUS. Describes communications standard Profibus, PLC and PC communication via PROFIBUS, API used for Profibus-PCI card, used programming language and development tool, a description of graphic and software parts of developed application Datalogger and finally describes the testing of developed applications datalogger.
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MIGRATING FROM A VAX/VMS TO AN INTEL/WINDOWS-NT BASED GROUND STATIONPenna, Sergio D., Rios, Domingos B. 10 1900 (has links)
International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Upgrading or replacing production systems is always a very resource-consuming task, in particular if the systems being replaced are quite specialized, such as those serving any Flight Test Ground Station. In the recent past a large number of Ground Station systems were based in Digital’s VAX/VMS architecture. The computer industry then expanded very fast and by 1990 realtime PCM data processing systems totally dependent on hardware and software designed for IBM-PC compatible micro-computers were becoming available. A complete system replacement in a typical Ground Station can take from one to several years to become a reality. It depends on how complex the original system is, how complex the resulting system needs to be, how much resources are available to support the operation, how soon the organization needs it, etc. This paper intends to review the main concerns encountered during the replacement of a typical VAX/VMS-based by an Intel-Windows NT-based Ground Station. It covers the transition from original requirements to totally new requirements, from mini-computers to micro-computers, from DMA to high-speed LAN data transfers, while conserving some key architectural features. This 8-month development effort will expand EMBRAER’s capability in acquiring, processing and archiving PCM data in the next few years at a lower cost, while preserving compatibility with old legacy flight test data.
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