6,357 research outputs found

    CAD Tool for Burn Diagnosis

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    In this paper a new system for burn diagnosis is proposed. The aim of the system is to separate burn wounds from healthy skin, and the different types of burns (burn depths) from each other, identifying each one. The system is based on the colour and texture information, as these are the characteristics observed by physicians in order to give a diagnosis. We use a perceptually uniform colour space (L*u*v*), since Euclidean distances calculated in this space correspond to perceptually colour differences. After the burn is segmented, some colour and texture descriptors are calculated and they are the inputs to a Fuzzy-ARTMAP neural network. The neural network classifies them into three types of burns: superficial dermal, deep dermal and full thickness. Clinical effectiveness of the method was demonstrated on 62 clinical burn wound images obtained from digital colour photographs, yielding an average classification success rate of 82 % compared to expert classified images

    Mitral Annular and Coronary Artery Calcification Are Associated with Mortality in HIV-Infected Individuals.

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    BackgroundHIV infection increases cardiovascular risk. Coronary artery calcification (CAC) and mitral annular calcification (MAC) identify patients at risk for cardiovascular disease (CVD). The purpose of this study was to examine the association between MAC, CAC and mortality in HIV-infected individuals.Methods and resultsWe studied 152 asymptomatic HIV-infected individuals with transthoracic echocardiography (TTE) and computed tomography (CT). MAC was identified on TTE using standardized criteria. Presence of CAC, CAC score and CAC percentiles were determined using the modified Agatston criteria. Mortality data was obtained from the Social Security and National Death Indices (SSDI/NDI). The median age was 49 years; 87% were male. The median duration of HIV was 16 years; 84% took antiretroviral therapy; 64% had an undetectable viral load. CVD risk factors included hypertension (35%), smoking (62%) and dyslipidemia (35%). Twenty-five percent of individuals had MAC, and 42% had CAC. Over a median follow-up of 8 years, 11 subjects died. Subjects with CAC had significantly higher mortality compared to those with MAC only or no MAC. The Harrell's C-statistic of CAC was 0.66 and increased to 0.75 when MAC was added (p = 0.05). MAC, prior CVD, age and HIV viral load were independently associated with higher age- and gender-adjusted CAC percentiles in an adjusted model (p < 0.05 for all).ConclusionIn HIV patients, the presence of MAC, traditional risk factors and HIV viral load were independently associated with CAC. Presence of CAC and MAC may be useful in identifying HIV-infected individuals at higher risk for death

    Segmentation and classification of burn images by color and texture information

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    In this paper, a burn color image segmentation and classification system is proposed. The aim of the system is to separate burn wounds from healthy skin, and to distinguish among the different types of burns (burn depths). Digital color photographs are used as inputs to the system. The system is based on color and texture information, since these are the characteristics observed by physicians in order to form a diagnosis. A perceptually uniform color space (L *u*v *) was used, since Euclidean distances calculated in this space correspond to perceptual color differences. After the burn is segmented, a set of color and texture features is calculated that serves as the input to a Fuzzy-ARTMAP neural network. The neural network classifies burns into three types of burn depths: superficial dermal, deep dermal, and full thickness. Clinical effectiveness of the method was demonstrated on 62 clinical burn wound images, yielding an average classification success rate of 82

    SOFT TOOL DEVELOPEMENT FOR CHARACTERIZATION OF LUNG NODULE FROM CHEST X-RAY IMAGE

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    CAD (Computer Aided Diagnosis) is a concept established by taking into account equally the roles of physician and computer to comment on disease. With CAD system, the performance given by computer does not have to be comparable to or better than that by physician, but need to be complementary to that by physician. To reduce the false positive and false negative diagnosis in determining whether the tumor is malignant or benign, doctors are taking help of CAD system. CAD using image processing technique has become one of the major research subjects in medical imaging and diagnostic radiology. Radiologist uses the CAD system output as a ‘second opinion’ and make the final decision to conform the disease. In present paper, suspicious area is segmented from the chest X-ray image after doing pre-processing of the image. Characterization of lung nodule means describing distinctive essential features. By doing segmentation, the features are extracted from the segmented region. All features are calculated from their respective mathematical formulas. Calculated features values vary according to arrangement of pixels in the image. Further this information can be used as an input to the CAD system for determining whether the segmented suspicious tumor area is malignant or benign. The proposed system will not replace the doctor’s role in detection of cancer but it will help doctor to take correct decision in short time with accuracy. It will act as second opinion before conformation of cancer

    Assessment of fuel consumption reduction strategies on a gasoline turbocharged direct injection engine with a cooled EGR system

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    [EN] This research work presents the study of a low pressure EGR loop influence on a SI gasoline turbocharged direct injection engine in steady and transient testing conditions, with an optimization process of the original engine calibration in order to minimize the engine fuel consumption when cooled EGR is introduced in steady testing conditions. The cooled EGR strategy was also evaluated operating in synergy with other fuel consumption reduction strategies, such as: lean burn, multi-injection, higher coolant temperature and in-cylinder induced swirl motion. To fulfill the main objectives of this research work, firstly, a methodical process was followed, where a global methodology was first developed in order to obtain high accuracy engine tests, based on the experimental tools chosen that could comply with the requirements of the testing conditions, and the appropriate theoretical tools and procedure to post-process the tests performed. Secondly, a specific methodology was developed for each stage of the study and testing conditions, taking into account optimization processes or parametric tests in order to study the effect of a single parameter on engine's outputs or optimize an engine parameter in order to minimize the engine fuel consumption. As a first stage of the study, a basic analysis of the impact of cooled EGR on the engine combustion, performance, air management and exhaust emissions is presented. Afterwards, an optimization of the combustion phasing in order to minimize the fuel consumption was performed, and therefore the potential of cooled EGR in order to reduce the engine fuel consumption was observed for low load, part load and full load engine conditions, for two different engine speeds. In addition, a study in transient conditions of the engine operating with cooled EGR was performed. NEDC cycles were performed with different EGR valve openings and therefore a comparison of different cooled EGR rates influence on the engine performance, air management and accumulated exhaust emissions was presented. The second stage, consisted in a methodology developed to optimize the VVT setting and injection timing, for part load engine conditions, in order to maximize the cooled EGR potential to reduce engine fuel consumption. After this optimization, a synergy analysis of the optimum engine condition operating with cooled EGR and three other engine fuel consumption reduction strategies was performed. These strategies were tested to investigate and evaluate the potential of increasing the cooled EGR operational range to further decrease the engine fuel consumption. Furthermore, a basic study of the potential to reduce the engine fuel consumption and impact on combustion, air management and exhaust emissions of a lean burn strategy, in part load engine conditions, was presented as introduction of the final study of the cooled EGR strategy operating in synergy with the lean burn strategy in order to investigate the potential to control the exhaust emissions and reduce the engine fuel consumption.[ES] El objetivo de este trabajo de investigación es estudiar la influencia de un lazo de baja presión de EGR en las prestaciones de un motor de gasolina de encendido provocado turbosobrealimentado e inyección directa, en condiciones de ensayos estacionarios y transitorios, con un proceso de optimización de la calibración original del motor para minimizar el consumo de combustible del motor. La estrategia de "cooled EGR" fue también evaluada operando en sinergia con otras estrategias usadas para reducir el consumo de combustible del motor, entre ellas: mezcla pobre, múltiples inyecciones, operación a alta temperatura del fluido refrigerante del motor y movimiento de "swirl" inducido en el cilindro. Para cumplir con los objetivos mencionados, se siguió un proceso metódico donde previamente se desarrolló una metodología global para obtener resultados de indudable calidad, basados en el uso de herramientas experimentales que cumplieran con los requerimientos de las condiciones de ensayo, y las apropiadas herramientas teóricas y procedimiento para post-procesar los ensayos realizados. En segundo lugar, se desarrolló una metodología específica para cada etapa del estudio, teniendo en cuenta los procesos de optimización o estudios paramétricos que se pudieran realizar. Como primera etapa, se presenta un estudio básico del impacto del "cooled EGR" en la combustión, prestaciones, renovación de la carga y emisiones contaminantes del motor. Seguidamente, se procedió a la optimización del centrado de la combustión con la finalidad de minimizar el consumo de combustible del motor y poder analizar el potencial del "cooled EGR" como estrategia de reducción de consumo de combustible. El estudio presentado se realizó para baja, media y alta carga del motor con dos diferentes regímenes de giro del motor. Adicionalmente, se llevó a cabo un estudio del motor operando en condiciones transitorias con "cooled EGR". Se realizaron una serie de ensayos usando el ciclo NEDC como base y se probaron diferentes estrategias sencillas de control de la apertura de la válvula de EGR para analizar la influencia del "cooled EGR" en condiciones transitorias. La segunda etapa consiste en el desarrollo de una metodología para optimizar los parámetros del diagrama de distribución (VVT) y el inicio de inyección, para cargas medias del motor, con la finalidad de maximizar el potencial de reducción de consumo de combustible de la estrategia "cooled EGR". Una vez realizada la optimización, se llevó a cabo un estudio usando la configuración óptima encontrada, operando en sinergia con otras tres estrategias usadas para reducir el consumo de combustible del motor. Estas estrategias fueron evaluadas con la finalidad de incrementar el rango de operación de la estrategia "cooled EGR" para lograr reducir aún más el consumo de combustible del motor. Adicionalmente, se llevó a cabo un estudio básico sobre la influencia de operar con mezcla pobre en la combustión, prestaciones, renovación de la carga y emisiones contaminantes del motor, como introducción al último estudio llevado a cabo sobre la posibilidad de usar la estrategia de mezcla pobre en conjunto con la estrategia de "cooled EGR", con la finalidad de analizar el potencial de controlar las emisiones contaminantes y reducir el consumo de combustible del motor al mismo tiempo.[CA] L'objectiu d'este treball d'investigació és estudiar la influència d'un llaç de baixa pressió d'EGR en les prestacions d'un motor de gasolina d'encesa provocat turbosobrealimentat i injecció directa, en condicions d'assajos estacionaris i transitoris, amb un procés d'optimització del calibratge original del motor per a minimitzar el consum de combustible del motor. L'estratègia de "cooled EGR" va ser també avaluada operand en sinergia amb altres estratègies usades per a reduir el consum de combustible del motor, entre elles: mescla pobra, múltiples injeccions, operació a alta temperatura del fluid refrigerant del motor i moviment de `"swirl" induït en el cilindre. Per a complir amb els objectius mencionats, es va seguir un procés metòdic on prèviament es va desenrotllar una metodologia global per a obtindre resultats d'indubtable qualitat, basats en l'ús de ferramentes experimentals que compliren amb els requeriments de les condicions d'assaig, i les apropiades ferramentes teòriques i procediment per a post- processar els assajos realitzats. En segon lloc, es va desenrotllar una metodologia específica per a cada etapa de l'estudi, tenint en compte els processos d'optimització o estudis paramètrics que es pogueren realitzar. Com a primera etapa, es presenta un estudi bàsic de l'impacte del "cooled EGR" en la combustió, prestacions, renovació de la càrrega i emissions contaminants del motor. A continuació, es va procedir a l'optimització del centrat de la combustió amb la finalitat de minimitzar el consum de combustible del motor i poder analitzar el potencial del "cooled EGR" com a estratègia de reducció de consum de combustible. L'estudi presentat es va realitzar per a baixa, mitja i alta càrrega del motor amb dos diferents règims de gir del motor. Addicionalment, es va dur a terme un estudi del motor operand en condicions transitòries amb "cooled EGR". Es van realitzar una sèrie d'assajos usant el cicle NEDC com a base i es van provar diferents estratègies senzilles de control de l'obertura de la vàlvula d'EGR per a analitzar la influència del "cooled EGR" en condicions transitòries. La segona etapa consistix en el desenrotllament d'una metodologia per a optimitzar els paràmetres del diagrama de distribució (VVT) i l'inici d'injecció, per a càrregues mitges del motor, amb la finalitat de maximitzar el potencial de reducció de consum de combustible de l'estratègia "cooled EGR". Una vegada realitzada l'optimització, es va dur a terme un estudi usant la configuració òptima trobada, operant en sinergia amb altres tres estratègies usades per a reduir el consum de combustible del motor. Estes estratègies van ser avaluades amb la finalitat d'incrementar el rang d'operació de l'estratègia "cooled EGR" per a aconseguir reduir encara més el consum de combustible del motor. Addicionalment, es va dur a terme un estudi bàsic sobre la influència d'operar amb mescla pobra en la combustió, prestacions, renovació de la càrrega i emissions contaminants del motor, com a introducció a l'últim estudi dut a terme sobre la possibilitat d'usar l'estratègia de mescla pobra en conjunt amb l'estratègia de "cooled EGR", amb la finalitat d'analitzar el potencial de controlar les emissions contaminants i reduir el consum de combustible del motor al mateix temps.Rivas Perea, ME. (2016). Assessment of fuel consumption reduction strategies on a gasoline turbocharged direct injection engine with a cooled EGR system [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/68497TESI

    Genomic architecture and prediction of censored time-to-event phenotypes with a Bayesian genome-wide analysis

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    While recent advancements in computation and modelling have improved the analysis of complex traits, our understanding of the genetic basis of the time at symptom onset remains limited. Here, we develop a Bayesian approach (BayesW) that provides probabilistic inference of the genetic architecture of age-at-onset phenotypes in a sampling scheme that facilitates biobank-scale time-to-event analyses. We show in extensive simulation work the benefits BayesW provides in terms of number of discoveries, model performance and genomic prediction. In the UK Biobank, we find many thousands of common genomic regions underlying the age-at-onset of high blood pressure (HBP), cardiac disease (CAD), and type-2 diabetes (T2D), and for the genetic basis of onset reflecting the underlying genetic liability to disease. Age-at-menopause and age-at-menarche are also highly polygenic, but with higher variance contributed by low frequency variants. Genomic prediction into the Estonian Biobank data shows that BayesW gives higher prediction accuracy than other approaches

    An investigation into the effects of commencing haemodialysis in the critically ill

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    <b>Introduction:</b> We have aimed to describe haemodynamic changes when haemodialysis is instituted in the critically ill. 3 hypotheses are tested: 1)The initial session is associated with cardiovascular instability, 2)The initial session is associated with more cardiovascular instability compared to subsequent sessions, and 3)Looking at unstable sessions alone, there will be a greater proportion of potentially harmful changes in the initial sessions compared to subsequent ones. <b>Methods:</b> Data was collected for 209 patients, identifying 1605 dialysis sessions. Analysis was performed on hourly records, classifying sessions as stable/unstable by a cutoff of >+/-20% change in baseline physiology (HR/MAP). Data from 3 hours prior, and 4 hours after dialysis was included, and average and minimum values derived. 3 time comparisons were made (pre-HD:during, during HD:post, pre-HD:post). Initial sessions were analysed separately from subsequent sessions to derive 2 groups. If a session was identified as being unstable, then the nature of instability was examined by recording whether changes crossed defined physiological ranges. The changes seen in unstable sessions could be described as to their effects: being harmful/potentially harmful, or beneficial/potentially beneficial. <b>Results:</b> Discarding incomplete data, 181 initial and 1382 subsequent sessions were analysed. A session was deemed to be stable if there was no significant change (>+/-20%) in the time-averaged or minimum MAP/HR across time comparisons. By this definition 85/181 initial sessions were unstable (47%, 95% CI SEM 39.8-54.2). Therefore Hypothesis 1 is accepted. This compares to 44% of subsequent sessions (95% CI 41.1-46.3). Comparing these proportions and their respective CI gives a 95% CI for the standard error of the difference of -4% to 10%. Therefore Hypothesis 2 is rejected. In initial sessions there were 92/1020 harmful changes. This gives a proportion of 9.0% (95% CI SEM 7.4-10.9). In the subsequent sessions there were 712/7248 harmful changes. This gives a proportion of 9.8% (95% CI SEM 9.1-10.5). Comparing the two unpaired proportions gives a difference of -0.08% with a 95% CI of the SE of the difference of -2.5 to +1.2. Hypothesis 3 is rejected. Fisher’s exact test gives a result of p=0.68, reinforcing the lack of significant variance. <b>Conclusions:</b> Our results reject the claims that using haemodialysis is an inherently unstable choice of therapy. Although proportionally more of the initial sessions are classed as unstable, the majority of MAP and HR changes are beneficial in nature

    Exploring the Mysteries of System-Level Test

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    System-level test, or SLT, is an increasingly important process step in today's integrated circuit testing flows. Broadly speaking, SLT aims at executing functional workloads in operational modes. In this paper, we consolidate available knowledge about what SLT is precisely and why it is used despite its considerable costs and complexities. We discuss the types or failures covered by SLT, and outline approaches to quality assessment, test generation and root-cause diagnosis in the context of SLT. Observing that the theoretical understanding for all these questions has not yet reached the level of maturity of the more conventional structural and functional test methods, we outline new and promising directions for methodical developments leveraging on recent findings from software engineering.Comment: 7 pages, 2 figure

    Advantages of hydrogen addition in a passive pre-chamber ignited SI engine for passenger car applications

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    [EN] Hydrogen is one of the most promising alternative fuels for the transportation industry. The use of hydrogen to enable lean burn in internal combustion engines is an attractive solution for reducing CO2 emissions from two points of views: the substitution of carbon-based fuels and the increased thermal efficiency due to lean operation. Combining this strategy with the passive pre-chamber ignition system with gasoline/hydrogen blends is even more interesting. The main limitations of the passive pre-chamber concept in a high compression ratio spark-ignition engine were shown through engine experiments. A numerical study was then performed to evaluate the chance of extending the dilution limit by using hydrogen along with this technology. Results show how the use of hydrogen provides considerable benefits in the main chamber combustion process by enhancing the thermo-chemical properties of the mixture, increasing the flame speed, and improving the flame structure. Using an adequate gasoline-hydrogen blend proved to enable optimum burning rates at lean conditions, leading to a relevant thermal efficiency gain.Ministerio de Economia, Industria y Competitividad, Gobierno de Espana, Grant/Award Number: TRA2017-89139-C2-1-R; Universitat Politecnica de Valencia, Grant/Award Number: FPI-S1-2019-0033Benajes, J.; Novella Rosa, R.; Gómez-Soriano, J.; Barbery-Avila, II.; Libert, C. (2021). Advantages of hydrogen addition in a passive pre-chamber ignited SI engine for passenger car applications. International Journal of Energy Research. 45(9):13219-13237. https://doi.org/10.1002/er.6648132191323745

    An information technology view of manufacturing automation - Product life-cycle management

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    Different approaches of product life-cycle management will be demonstrated to show that unlike several engineering paradigms it is easy to understand, however difficult to implement and to follow. This can be accepted as a common philosophy of product development and production. At the same time product life-cycle management is a software framework, or a kind of guideline to approach digital manufacturing, which is the highest level of recently known and applied ways of manufacturing automation. The paper will show some components of manufacturing automation and their relation to the life-cycle view. © 2016 Akadémiai Kiadó, Budapest
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