112 research outputs found

    Optimal multisensor data fusion for linear systems with missing measurements

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    Multisensor data fusion has attracted a lot of research in recent years. It has been widely used in many applications especially military applications for target tracking and identification. In this paper, we will handle the multisensor data fusion problem for systems suffering from the possibility of missing measurements. We present the optimal recursive fusion filter for measurements obtained from two sensors subject to random intermittent measurements. The noise covariance in the observation process is allowed to be singular which requires the use of generalized inverse. Illustration example shows the effectiveness of the proposed filter in the measurements loss case compared to the available optimal linear fusion methods.<br /

    Robust filtering for uncertain discrete-time systems with uncertain noise covariance and uncertain observations

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    The use of Kalman filtering is very common in state estimation problems. The problem with Kalman filters is that they require full prior knowledge about the system modeling. It is also assumed that all the observations are fully received. In real applications, the previous assumptions are not true all the time. It is hard to obtain the exact system model and the observations may be lost due to communication problems. In this paper, we consider the design of a robust Kalman filter for systems subject to uncertainties in the state and white noise covariances. The systems under consideration suffer from random interruptions in the measurements process. An upper bound for the estimation error covariance is proposed. The proposed upper bound is further minimized by selection of optimal filter parameters. Simulation example shows the effectiveness of the proposed filter.<br /

    Ablative Fractional 10 600 nm Carbon Dioxide Laser Versus Non-ablative Fractional 1540 nm Erbium-Glass Laser in Egyptian Post-acne Scar patients

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    Introduction: Non-ablative fractional erbium-doped glass 1540 nm and fractional ablative 10600 nm carbon dioxide lasers are regarded as effective modalities for treating acne atrophic scars. In this study, we aimed to compare the effectiveness of fractional CO2 laser and fractional non-ablative 1540 nm erbium doped glass laser in treating post acne atrophic scars in Egyptian patients.Methods: Fifty-eight patients complaining of moderate and severe acne atrophic scars were randomly divided into 2 groups of 29 patients each. Both groups were subjected to 4 treatment sessions with 3 weeks interval and were followed up for 3 months. In group A, enrolled patients received CO2 laser, while in group B, patients were treated with 1540 nm erbium glass fractional laser.Results: Clinical assessment revealed that the mean grades of progress and improvement were higher with fractional 10600 nm CO2 laser but with non-significant difference between both treatments (P = 0.1). The overall patients’ satisfaction with both lasers were not significantly different (P = 0.44).Conclusion: Both fractional ablative CO2 and fractional non-ablative erbium glass lasers are good modalities for treating acne scars with a high efficacy and safety profile and good patient satisfaction. The fractional ablative laser showed higher efficacy while non-ablative laser offered less pain and shorter downtime

    A Review on Robot Manipulation Methods in Human-Robot Interactions

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    Robot manipulation is an important part of human-robot interaction technology. However, traditional pre-programmed methods can only accomplish simple and repetitive tasks. To enable effective communication between robots and humans, and to predict and adapt to uncertain environments, this paper reviews recent autonomous and adaptive learning in robotic manipulation algorithms. It includes typical applications and challenges of human-robot interaction, fundamental tasks of robot manipulation and one of the most widely used formulations of robot manipulation, Markov Decision Process. Recent research focusing on robot manipulation is mainly based on Reinforcement Learning and Imitation Learning. This review paper shows the importance of Deep Reinforcement Learning, which plays an important role in manipulating robots to complete complex tasks in disturbed and unfamiliar environments. With the introduction of Imitation Learning, it is possible for robot manipulation to get rid of reward function design and achieve a simple, stable and supervised learning process. This paper reviews and compares the main features and popular algorithms for both Reinforcement Learning and Imitation Learning

    Dynamic MR-Mammography as the best method for diagnosis of invasive lobular breast carcinoma: A retrospective study

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    AbstractAim of the studyIt is a retrospective study aiming to provide diagnostic characterization of ILC in Dynamic MR-Mammography and to compare its diagnostic performance to mammography and ultrasonography.Material and MethodA total of 56 cases of ILC were selected in retrospective review of mammography, ultrasonography and Dynamic MRM of 420 patients with invasive breast cancer.ResultsAsymmetric density was the commonest mammography finding and the measured sensitivity of mammography in detecting ILC was 87.5% (9/56 FN).The most common US manifestation of ILC was focal shadowing without a discrete mass and its sensitivity in detecting ILC was 84.9% (10/56 FN). At MR imaging, the most common manifestation of ILC was a solitary irregular or angular mass with speculated or ill-defined margins (33.9%of cases [n=19]).The measured sensitivity is 96.5% (2/56 FN). Additional data such as those affected the patient management including the presence of multifocal or multicentric disease, chest wall involvement and contralateral breast cancer were encountered in 48.2% of cases [n=27]. ILC has a tendency to demonstrate delayed maximum enhancement with washout exhibited by only a minority of lesions (21.4% [n=12]).ConclusionMR imaging has proved to be superior to mammography and US in the detection and management of ILC. It provides useful information for further management and pre-surgical planning

    Radiometric Characterization, Solar and Thermal Radiation in a Greenhouse as Affected by Shading Configuration in an Arid Climate.

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    Shading the greenhouses is necessary in summer to reduce the solar radiation load. This however generates a considerable amount of thermal radiation heat load that needs to be removed via cooling systems. This study aimed to evaluate the effect of different shading configurations on the solar and thermal radiation in a greenhouse. Nets at four different locations were employed to shade the roof and side-walls of a polycarbonate, mechanically ventilated greenhouse. The spectral radiative properties of all these plastic materials were measured in short and long wave spectrum bands. The net solar and thermal radiations and air temperature were measured outside and inside two identical shaded and unshaded greenhouses. The results showed that external roof-shading is desirable, as it reduced the generated thermal radiation in the greenhouse by 21% and 15% during the day and night time, respectively and reduced the greenhouse air temperature during the day. The internal shading (roof and side walls) is undesirable, since it drastically increased the generated thermal radiation in the greenhouse by 147% and strongly increased the greenhouse air temperature during the day. Shading the side-walls is not recommended because it significantly reduces the transmitted solar radiation in the morning and afternoon (when the outside irradiance is low) and is useless at around noon when the outside irradiance is extremely high

    Nitric oxide levels in chronic liver disease patients with and without oesophageal varices

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    Introduction Patients with chronic liver disease ultimately progress to develop cirrhosis and portal hypertension. Recently it seems well established that nitric oxide disturbances play a key role in the pathogenesis of chronic liver disease and portal hypertension. The aim of this work was to clarify the correlation between chronic liver disease stages, liver function status, esophageal varices presence and nitric oxide disturbances. Subjects and methods All subjects (n = 120) in the present study were classified into; group I which included 15 age and sex matched healthy volunteers (taken as control), group II which included 20 patients with chronic active hepatitis, and group III which included 85 patients with hepatic cirrhosis. All subjects included were subjected to full clinical assessment, routine laboratory investigations, serum nitrate level determination using colorimetric method, abdominal ultrasonography and upper endoscopy. Results Increased serum nitrate level could not be detected in patients with chronic active hepatitis as well as those with early cirrhosis (Child’s class A). Progressive and significant increase of serum nitrate levels were detected in more advanced stages of cirrhosis (Child’s class B & C). The best non-invasive predictor for the presence of oesophageal varices was a combination of platelet count <150.000/mm3, splenomegaly >18 cm, Child’s class B or C and serum nitrate ≥38 μmol/l, with 93.3% sensitivity and 100% specificity. Conclusion Serum nitrate level can be used as a non-invasive predictor for progression of chronic liver disease as well as for the presence of oesophageal varices

    Chicory abrogates oxidative stress, inflammation and caspase-dependent apoptosis in acute hepatic injury model induced by acetaminophen in rats

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    In this study the protective effect of chicory leaves hydroalcoholic extract (CIE) against acute liver injury induced by a single dose of acetaminophen (700 mg/kg, i.p.) was investigated in rats. The CIE and silymarin treatment (standard reference) were given in a dose of (100 mg/kg, p.o.) for 3 days before and at 1 and 12 h following acetaminophen administration. Treatment with CIE significantly reduced the levels of serum ALT, AST, alkaline phosphatase, bilirubin, total cholesterol, triglycerides, urea, creatinine, TNF-α and hepatic contents of malondialdehyde (MDA), nitric oxide, caspase-3 and hydroxyproline, with significant increases in serum total protein, albumin, HDL- cholesterol and hepatic activities of reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) as compared with the acetaminophen group. The histopathological alterations mediated by acetaminophen were ameliorated by CIE. It was concluded that CIE protects rat liver against acetaminophen hepatotoxicity, most probably through abrogation of oxidative stress, inflammation and caspase-3 dependent apoptosis

    Neurocognitive Function and Its Related Potentials in Children with Beta Thalassemia Major: An Egyptian Study

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    BACKGROUND: Repeated blood transfusions and hemolysis in β-Thalassemia major children lead to iron overload in various organs, including the brain which may cause neurodegeneration. AIM: To evaluate intelligence quotient in children with β-thalassemia major and healthy counterparts and to assess risk factors that cause cognitive problems. SUBJECTS AND METHODS: This case-control study was performed on 50 children aged 6-16 years old with β-thalassemia major as patients group and compared with 50 healthy children as a control group of matched age, sex, and social class. Cognitive functions were evaluated by using the Wechsler Intelligence Scale for Children. Serum ferritin and iron were measured by ELISA. RESULTS: There were significantly lower mean performance and full-scale IQ scores of patients group in comparison with controls, whereas no significant differences between both groups as regards to a verbal IQ score. In thalassemic children, block design, comprehension and arithmetic were negatively correlated with age of disease onset, duration of illness and onset of chelation therapy. Serum iron and ferritin were negatively correlated with similarities and digit span. Serum iron levels were negatively correlated with performance IQ score. CONCLUSION: Children with β-thalassemia major need to receive more academic attention and cognitive assessment to improve their IQ
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