Control design for UAV quadrotors via embedded model control

In this paper, a control system for unmanned aerial vehicles (UAVs) is designed, tested in simulation by means of a high-fidelity simulator, and then applied to a real quadrotor UAV. A novel approach is proposed for the control design, based on the combination of two methodologies: feedback linearization (FL) and embedded model control (EMC). FL allows us to properly transform the UAV dynamics into a form suitable for EMC; EMC is then used to control the transformed system. A key feature of EMC is that it encompasses a so-called extended state observer (ESO), which not only recovers the system state but also gives a real-time estimate of all the disturbances/uncertainties affecting the system. This estimate is used by the FL-EMC control law to reject the aforementioned disturbances/uncertainties, including those collected via the FL, allowing a robustness and performance enhancement. This approach allows us to combine FL and EMC strengths. Most notably, the entire process is made systematic and application oriented. To set-up a reliable UAV attitude observer, an effective attitude sensors fusion is proposed and also benchmarked with an enhanced complementary filter. Finally, to enhance the closed-loop performance, a complete tuning procedure, encompassing frequency requirements, is outlined, based on suitably defined stability and performance metrics

Satellite-to-satellite attitude control of a long-distance spacecraft formation for the Next Generation Gravity Mission

The paperpresentsthedesignandsomesimulatedresultsoftheattitudecontrolofasatelliteformation under studybytheEuropeanSpaceAgencyfortheNextGenerationGravityMission.Theformation consists oftwospacecraftswhich fly morethan200kmapartatanaltitudefromtheEarth'sgroundof between 300and400km.Theattitudecontrolmustkeeptheopticalaxesofthetwospacecraftaligned with amicroradianaccuracy(pointingcontrol).Thisismadepossiblebyspecific opticalsensors accompanyingtheinter-satellitelaserinterferometer,whichisthemainpayloadofthemission.These sensors alloweachspacecrafttoactuateautonomousalignmentafterasuitableacquisitionprocedure. Pointing controlisconstrainedbytheangulardrag-freecontrol,whichisimposedbymissionscience (Earth gravimetryatalowEarthorbit),andmustzerotheangularaccelerationvectorbelow0.01 μrad/s2 in thesciencefrequencyband.Thisismadepossiblebyultrafine accelerometersfromtheGOCE-class, whose measurementsmustbecoordinatedwithattitudesensorstoachievedrag-freeandpointing requirements.EmbeddedModelControlshowshowcoordinationcanbeimplementedaroundthe embedded modelsofthespacecraftattitudeandoftheformationframequaternion.Evidenceand discussion aboutsomecriticalrequirementsarealsoincludedtogetherwithextensivesimulatedresults of twodifferentformationtypes

Luz solar e suicídio no trópico de Capricórnio, São Paulo, Brasil, 1996-2004

Estudos epidemiológicos têm confirmado que as taxas de suicídio apresentam variação sazonal relacionada às horas de insolação. O padrão de suicídios foi analisado na cidade de São Paulo, Brasil, no trópico de Capricórnio, de 1996 a 2004. A regressão de Poisson foi utilizada para estimar padrões de sazonalidade, bem como verificar a associação dia-a-dia entre duração da insolação e suicídio. Durante os nove anos houve 3.984 suicídios (76,9% homens; mediana de idade=38,7 anos). As médias de suicídio por estação do ano e por mês de suicídio foram similares. Segundo a regressão de Poisson, não houve associação entre insolação e suicídio (p=0,45) para ambos os sexos. Conclui-se que não houve padrão sazonal de suicídios na cidade de São Paulo.Several studies have confirmed seasonal variation in suicide rates according to hours of sunshine. The suicide pattern was assessed in São Paulo, southeastern Brazil, at the tropic of Capricorn from 1996 to 2004. Poisson regression was employed to estimate parameters of seasonality, as well as to verify associations for each day between daylight duration and suicide. During the nine-year study period, there were 3,984 suicides (76.9% in men; median age=38.7 years old). Seasonal averages of suicides were similar, as were monthly averages. Poisson regression did not reveal any association between suicide rates and hours of sunshine (p=0.45) for both sexes. In conclusion, no seasonal pattern was observed for suicides

Resultados de oito aplicações do Teste do Progresso na Faculdade de Medicina da Universidade de São Paulo

BACKGROUND: Progress testing is a longitudinal tool for evaluating knowledge gains during the medical school years. OBJECTIVES: (1) To implement progress testing as a form of routine evaluation; (2) to verify whether cognitive gain is a continuous variable or not; and (3) to evaluate whether there is loss of knowledge relating to basic sciences in the final years of medical school. METHODS: A progress test was applied twice a year to all students from 2001 to 2004. The mean percentage score was calculated for each school year, employing ANOVA with post hoc Bonferroni test evaluation for each test. RESULTS: Progress testing was implemented as a routine procedure over these 4 years. The results suggest a cognitive gain from first to sixth year in all eight tests, as a continuum (P for trend < .0001). Gain was found to be continuous for basic sciences (taught during the first 2 years), clinical sciences (P < .0001), and clerkship rotation (P < .0001). There was no difference between the performance of men and women. CONCLUSION: Progress testing was implemented as a routine, applied twice a year. Data suggest that cognitive gain during medical training appears to be a continuum, even for basic science issues.O Teste do Progresso foi introduzido na Faculdade de Medicina da Universidade de São Paulo em 2001. OBJETIVO: (1) Testar a viabilidade da aplicação rotineira do teste; (2) verificar se o ganho de conhecimentos era progressivo e contínuo durante a graduação; (3) determinar se esse ganho de conhecimento inclui também as disciplinas do curso básico. MÉTODOS: O teste foi aplicado duas vezes por ano entre 2001-2004. Em cada teste, calculou-se o escore médio de acertos por ano letivo usando-se ANOVA com correção de Bonferroni para múltiplas comparações. RESULTADOS: O Teste do Progresso foi implementado como rotina entre 2001-2004. Os resultados sugerem um ganho cognitivo contínuo e progressivo ao longo da graduação (P < 0,0001) nos oito testes aplicados até o momento. Esse ganho seria significativo mesmo para as disciplinas do curso básico (P < 0,05), curso clínico (P < 0.0001) e internato (P < 0.0001). Não houve diferença de performance em função do gênero. CONCLUSÃO: O Teste do Progresso foi implementado como rotina, sendo aplicado semestralmente. Os resultados sugerem que o ganho cognitivo parece ser contínuo e progressivo mesmo para as disciplinas do básico ao longo dos seis anos

Prevalência de doenças da tireóide em idosos: resultados do São Paulo Ageing & Health Study

This study aimed to estimate prevalence of thyroid disorders in the São Paulo Ageing & Health Study, an epidemiological study addressing several health-adverse outcomes among elderly people living in a poor area of São Paulo, Brazil. All participants answered a questionnaire and had a blood sample collected to assess levels of tireotropic hormone and free-thyroxine. Among 1,373 people (60.8% women), prevalence rates (95% confidence interval) for thyroid dysfunction (%) were: overt hyperthyroidism, 0.7% (0.2-1.1)[women: 0.8% (0.2-1.5); men: 0.4% (0.01-0.9)]; overt hypothyroidism, 5.7% (4.5-6.9) [women: 5.9% (4.3-7.5); men: 5.4% (3.5-7.3)]; subclinical hyperthyroidism, 2.4% (1.6-3.2) [women: 2.8% (1.6-3.9); men: 1.9% (0.7-3.0)]; and subclinical hypothyroidism, 6.5% (5.2-7.8) [women: 6.7% (5.0-8.4); men: 6.1% (4.1-8.2)]. There was no difference in prevalence rates according to gender, but almost 40% of women were diagnosed and under treatment compared to 9% of men. The burden of thyroid disorders in this sample is high and most participants were not aware of them.O objetivo da pesquisa foi avaliar a prevalência de doenças da tireóide no São Paulo Ageing & Health Study, estudo epidemiológico focado em desfechos de saúde adversos em amostra de idosos moradores de São Paulo, Brasil. Todos os participantes responderam a questionário e colheram sangue para dosagem de hormônio tireotrópico e tiroxina-livre. Entre os 1.373 participantes (60,8% mulheres), a prevalência (intervalo de 95% de confiança) de hipertireoidismo clínico foi de 0,7% (0.2-1,1) [mulheres: 0,8% (0,2-1,5); homens: 0,4% (0,01-0,9)]; hipotireoidismo clínico, 5,7% (4,5-6,9) [mulheres: 5,9% (4,3-7,5); homens: 5,4% (3,5-7,3)]; hipertireoidismo subclínico, 2,4% (1,6-3,2) [mulheres: 2,8% (1,6-3,9); homens: 1,9% (0,7-3,0)]; e hipotireoidismo subclínico, 6,5% (5,2-7,8) [mulheres: 6,7% (5,0-8,4); homens: 6,1% (4,1-8,2)]. Não houve diferença na prevalência de doenças da tireóide por sexo. Quarenta por cento das mulheres tinham diagnóstico e estavam tratando, comparadas a 9% dos homens. A prevalência de disfunção tireoidiana foi elevada e a maioria dos participantes desconhecia o diagnóstico.(FAPESP) São Paulo Research Foundatio

How doctors diagnose diseases and prescribe treatments: an fMRI study of diagnostic salience

Understanding the brain mechanisms involved in diagnostic reasoning may contribute to the development of methods that reduce errors in medical practice. In this study we identified similar brain systems for diagnosing diseases, prescribing treatments, and naming animals and objects using written information as stimuli. Employing time resolved modeling of blood oxygen level dependent (BOLD) responses enabled time resolved (400 milliseconds epochs) analyses. With this approach it was possible to study neural processes during successive stages of decision making. Our results showed that highly diagnostic information, reducing uncertainty about the diagnosis, decreased monitoring activity in the frontoparietal attentional network and may contribute to premature diagnostic closure, an important cause of diagnostic errors. We observed an unexpected and remarkable switch of BOLD activity within a right lateralized set of brain regions related to awareness and auditory monitoring at the point of responding. We propose that this neurophysiological response is the neural substrate of awareness of one’s own (verbal) response. Our results highlight the intimate relation between attentional mechanisms, uncertainty, and decision making and may assist the advance of approaches to prevent premature diagnostic closure

The influence of the day of the week of hospital admission on the prognosis of stroke patients

This study aimed to evaluate the weekday and weekend distribution of stroke case hospital admissions and their respective prognosis based on a sample from the Estudo de Mortalidade e Morbidade do Acidente Vascular Cerebral (EMMA), a cohort of stroke patients admitted to a community hospital in the city of São Paulo, Brazil. We ascertained all consecutive cases of first-time strokes between April 2006 and December 2008 and performed a subsequent one-year follow-up. No association was found between frequency of hospital admissions due to ischemic and hemorrhagic strokes and the specific day of the week on which the admission occurred. However, ten-day and twelve-month case-fatality was higher in hemorrhagic stroke patients admitted at the weekend. We also found that intracerebral hemorrhage patients admitted on weekends had a worse survival rate (50%) compared with those admitted during weekdays (25.6%, P log-rank = 0.03). We found a multivariate hazard ratio of 2.49 (95%CI: 1.10-5.81, P trend = 0.03) for risk of death at the weekend compared to weekdays for intracerebral hemorrhage cases. No difference in survival was observed with respect to the overall sample of stroke or ischemic stroke patients

The Acute-Phase Proteins Serum Amyloid A and C Reactive Protein in Transudates and Exudates

The distinction between exudates and transudates is very important in the patient management. Here we evaluate whether the acute-phase protein serum amyloid A (SAA), in comparison with C reactive protein (CRP) and total protein (TP), can be useful in this discrimination. CRP, SAA, and TP were determined in 36 exudate samples (27 pleural and 9 ascitic) and in 12 transudates (9 pleural and 3 ascitic). CRP, SAA, and TP were measured. SAA present in the exudate corresponded to 10% of the amount found in serum, that is, the exudate/serum ratio (E/S) was 0.10 ± 0.13. For comparison, the exudate/serum ratio for CRP and TP was 0.39 ± 0.37 and 0.68 ± 0.15, respectively. There was a strong positive correlation between serum and exudate SAA concentration (r = 0.764;p < 0.0001). The concentration of SAA in transudates was low and did not overlap with that found in exudates (0.02-0.21 versus 0.8–360.5 g/mL). SAA in pleural and ascitic exudates results mainly from leakage of the serum protein via the inflamed membrane. A comparison of the E/S ratio of SAA and CRP points SAA as a very good marker in discriminating between exudates and transudates

Nível de escolaridade e dependência funcional em sobreviventes de acidente vascular cerebral isquêmico

We evaluated the functional dependence of stroke survivors from the Study of Stroke Mortality and Morbidity, using the Rankin Scale. Out of 355 ischemic stroke survivors (with a mean age of 67.9 years), 40% had some functional dependence at 28 days and 34.4% had some functional dependence at 6 months. Most predictors of physical dependence were identified at 28 days. These predictors were: low levels of education [illiterate vs. &gt;= 8 years of education, multivariate odds ratio (OR) = 3.7; 95% confidence interval (95%CI): 1.60-8.54] and anatomical stroke location (total anterior circulation infarct, OR = 16.9; 95%CI: 2.93-97.49). Low levels of education and ischemic brain injury influenced functional dependence in these stroke survivors. Our findings reinforce the necessity of developing strategies for the rehabilitation of stroke patients, more especially in formulating specific strategies for care and treatment of stroke survivors with low socioeconomic status.Foi avaliada a dependência funcional em sobreviventes de acidente vascular cerebral (AVC) do Estudo da Mortalidade e Morbidade do Acidente Vascular Cerebral, utilizando a Escala de Rankin. De 355 sobreviventes com AVC isquêmico (idade média de 67,9 anos), 40% tinham dependência funcional em 28 dias e 34,4% em 6 meses. Os principais indicadores de dependência física foram identificados em 28 dias, e eram: baixa escolaridade (analfabetos vs. > 8 anos de educação, RC = 3,7; IC95%: 1,60-8,54) e localização do AVC (infarto circulação total anterior, RC = 16,9; IC95%: 2,93-97,49). Baixo nível educacional e insulto cerebral isquêmico influenciaram o grau de dependência funcional nesses sobreviventes de AVC. Nossos achados reforçam a necessidade de desenvolvimento de estratégias para reabilitação de pacientes com AVC e formulação de estratégias específicas de atenção e tratamento para essas pessoas, especialmente na população com baixo nível socioeconômico.CNPqFAPES