239 research outputs found

    Constraint reasoning with local search for continuous optimization

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    Optimization is a very important field for getting the best possible value for the optimization function. Continuous optimization is optimization over real intervals. There are many global and local search techniques. Global search techniques try to get the global optima of the optimization problem. However, local search techniques are used more since they try to find a local minimal solution within an area of the search space. In Continuous Constraint Satisfaction Problems (CCSP)s, constraints are viewed as relations between variables, and the computations are supported by interval analysis. The continuous constraint programming framework provides branch-and-prune algorithms for covering sets of solutions for the constraints with sets of interval boxes which are the Cartesian product of intervals. These algorithms begin with an initial crude cover of the feasible space (the Cartesian product of the initial variable domains) which is recursively refined by interleaving pruning and branching steps until a stopping criterion is satisfied. In this work, we try to find a convenient way to use the advantages in CCSP branchand- prune with local search of global optimization applied locally over each pruned branch of the CCSP. We apply local search techniques of continuous optimization over the pruned boxes outputted by the CCSP techniques. We mainly use steepest descent technique with different characteristics such as penalty calculation and step length. We implement two main different local search algorithms. We use “Procure”, which is a constraint reasoning and global optimization framework, to implement our techniques, then we produce and introduce our results over a set of benchmarks

    The Role of a Deglycating Enzyme ‘Fructosamine-3-Kinase’ in Diabetes and COPD.

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    A thesis submitted in partial fulfilment of the requirements of the University of Wolverhampton for degree of Doctor of Philosophy.Recent statistics show that approximately 415 million people worldwide have diabetes. Glycated haemoglobin (HbA1c) measurements were introduced many years ago as the gold standard tool for detecting and monitoring treatment as well as making management decisions for diabetic patients. Glycated haemoglobins are formed by the non-enzymatic glycation of haemoglobin molecules. This non-enzymatic glycation process has been strongly related to pathogenesis of chronic complications associated to diabetes. It was suggested that this glycation process may be moderated by an enzymatic deglycation process thought to involve a deglycating enzyme known as Fructosamine-3-kinase (FN3K), an enzyme that deglycates the glycated haemoglobin in erythrocytes and other glycated proteins in other tissues. FN3K acts through phosphorylation of fructosamines on the third carbon of their sugar moiety, making them unstable and consequently causing them to detach from the protein. The degree of deglycation is thought to depend on the activity of the FN3K enzyme. Moreover, variation in the activity of FN3K between individuals is hypothesised to lead to apparent differences in glycated haemoglobin levels: some individuals have high rates of deglycation so that they tend to have lower average glycaemia than actually the case, while others with low rates of deglycation appear to have higher than actual glycaemia (known as the glycation gap, G-gap). The G-gap has been reported to be associated with alteration of diabetic complications risk. The G-gap reflects the discrepancy between average glycaemia as determined from glycated haemoglobin (measured as HbA1c) and that from the determination of fructosamine. The positive G-gap is defined as a higher level of glycation of proteins than expected whereas a negative G-gap means a lower level of glycation than expected. To explore the role of FN3K in diabetes and other associated morbidities, we decided to divide our research into 3 studies. Each study was categorised according to the type and the source of samples involved. The first study explored the correlation between FN3K activity and protein level with G-gap data; it involved 148 diabetic patients who were recruited at New Cross Hospital, Wolverhampton, selected as having a consistent positive G-gap > +0.5 and a consistent negative G-gap > -0.5 over a minimum of 2 estimations. Age, gender, race and BMI were collected from patients in this study. Blood samples were also 3 collected to measure FN3K activity, protein levels, and markers of CVD in relation to G-gap. The second study involved 23 AECOPD patients who were recruited from St George’s Hospital (London) and were treated with either metformin or a placebo. Serum samples were collected from these patients for a larger study: we assayed those 23 serum samples for FN3K protein levels to explore any possible correlation between FN3K with metformin therapy in COPD patients. The third study utilised 36 human peripheral lung samples from healthy individuals, asymptomatic smokers and stable COPD patients (GOLD 2) who were recruited at The Section of Respiratory Medicine, University Hospital of Ferrara, Italy. Those samples were assessed for FN3K expression by means of immunohistochemistry to explore the difference in FN3K activity between those three categories. It was found that the intracellular activity and protein expression of the FN3K enzyme in diabetic patients negatively correlated with the values of G-gaps where FN3K activity was high in patients with negative G-gap. FN3K serum protein levels were shown to be enhanced with metformin administration in COPD diabetic patients, suggesting a protective role for FN3K enzyme against protein damaged caused by the non-enzymatic glycation of proteins. Therefore, patients with positive G-gap have lower FN3K activity than those with negative G-gap, and in turn they are more susceptible to diabetes related complications. Our data also indicate that metformin has a beneficial effect in reducing damage caused by carbonyl stress from cigarette smoking in COPD patients by the action of FN3K. Our research has demonstrated that FN3K contributes to the protein repair system which protects against damage caused by non-enzymatic glycation. The high activity for the FN3K enzyme was associated with low levels of AGEs and low carbonyl stress levels in observed among patients with diabetes and COPD. In contrast, COPD patients tend to have low FN3K-mediated protection against protein damage in comparison to the normal population. These patients tend to be at risk for developing more complications, particularly CVD complications, than normal, healthy individuals. Treatment with metformin enhances FN3K action in COPD diabetic patients, possibly as a protective enzyme against the damaged caused by the non-enzymatic glycation

    Ensemble Classifier for Epileptic Seizure Detection for Imperfect EEG Data

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    Brain status information is captured by physiological electroencephalogram (EEG) signals, which are extensively used to study different brain activities.This study investigates the use of a new ensemble classifier to detect an epileptic seizure from compressed and noisy EEG signals. This noise-aware signal combination (NSC) ensemble classifier combines four classification models based on their individual performance. The main objective of the proposed classifier is to enhance the classification accuracy in the presence of noisy and incomplete information while preserving a reasonable amount of complexity.The experimental results show the effectiveness of the NSC technique, which yields higher accuracies of 90% for noiseless data compared with 85%, 85.9%, and 89.5% in other experiments. The accuracy for the proposed method is 80% when SNR = 1dB, 84% when SNR = 5dB, and 88% when SNR = 10dB, while the compression ratio (CR) is 85.35% for all of the datasets mentioned.NPRP 7-684-1-127, from the Qatar National Research Fund, a member of Qatar Foundation

    Effervescent Atomization of Suspensions in a Gaseous Cross Flow

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    Atomization of liquids (pure liquids and suspensions) plays an important role in numerous industrial fields and applications. One of the main important applications is in thermal spraying processes which is the primary motivation for this study. The main trend in thermal spray processes is to coat with sub-micron and nano sized particles due to the superior performance of fine microstructured coatings. Recently, thermal spraying processes are using the suspension spraying technique. The breakup of a suspension in the atomization process differs from that of a pure liquid by the influence of the suspended particles on the fragmentation kinetics. In suspension spraying process, different types of atomizers are used but clogging problems can occur due to the suspension properties. Effervescent atomizers have shown to be a good alternative to the conventional atomizers to solve clogging issue when liquids with large variety of viscosity and density such as suspensions are atomized. In this study, effervescent atomization of suspensions in a crossflow of air is investigated experimentally. The tests have been performed at different liquid-to-gas momentum flux ratios (q) and different gas to liquid ratios (GLR). Hydrophilic and hydrophobic particles are used in the experiments. Shadowgraphy and image processing have been used in order to capture the penetration height of the spray. New correlations have been developed to predict the spray penetration height of suspensions in case the non-aerated liquid jet (GLR= 0) and for the aerated liquid jet (GLR ≠ 0). Moreover, suspensions properties such as viscosity and surface tension have a crucial effect on the atomization process. Because the atomization process and droplet formation occur in a very short timescale of the order of milliseconds, it is necessary to analyze the rapid change of the affecting suspension properties related to this timescale especially surface tension. Therefore, the time changing (dynamic) surface tension is more appropriate to be analyzed than static surface tension. In this work, the dynamic surface tension of suspensions is investigated using a combined analytical and experimental approach based on the physics governing the oscillation of elliptical jets. The dynamic surface tension of suspensions liquids in the timescale of milliseconds is calculated. The effect of the dynamic surface tension of suspension on its atomization process has been analyzed

    A Multi-Objective Optimization Method for Hospital Admission Problem—A Case Study on Covid-19 Patients

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    The wide spread of Covid-19 has led to infecting a huge number of patients, simultaneously. This resulted in a massive number of requests for medical care, at the same time. During the first wave of Covid-19, many people were not able to get admitted to appropriate hospitals because of the immense number of patients. Admitting patients to suitable hospitals can decrease the in-bed time of patients, which can lead to saving many lives. Also, optimizing the admission process can minimize the waiting time for medical care, which can save the lives of severe cases. The admission process needs to consider two main criteria: the admission time and the readiness of the hospital that will accept the patients. These two objectives convert the admission problem into a Multi-Objective Problem (MOP). Pareto Optimization (PO) is a common multi-objective optimization method that has been applied to different MOPs and showed its ability to solve them. In this paper, a PO-based algorithm is proposed to deal with admitting Covid-19 patients to hospitals. The method uses PO to vary among hospitals to choose the most suitable hospital for the patient with the least admission time. The method also considers patients with severe cases by admitting them to hospitals with the least admission time regardless of their readiness. The method has been tested over a real-life dataset that consisted of 254 patients obtained from King Faisal specialist hospital in Saudi Arabia. The method was compared with the lexicographic multi-objective optimization method regarding admission time and accuracy. The proposed method showed its superiority over the lexicographic method regarding the two criteria, which makes it a good candidate for real-life admission systems

    Second law efficiency analysis of air injection into inner tube of double tube heat exchanger

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    At present study, thermal performance of a double tube heat exchanger due to stream of air/water two phase flow through inner tube is experimentally studied. Air and hot water were mixed in a T-junction outside heat exchanger and then were followed into inner tube of heat exchanger. Told water flow rate was kept constant and was equal to 2 lit/min. For hot water flow rate, four different flow rates of 3, 4, 5 and 6 lit/min was considered. Also inlet temperature of cold and hot water streams were almost constant and were within range of 17–19 C and 48–50 C. Also, for air flow rate five different flow rates of 1, 2, 3, 4 and 5 lit/min were considered. Volume fraction was within the range of 0.14 and 0.62. Obtained results were analyzed based on several energetic and exergitic parameters including pressure drop, effectiveness, Number of Transfer Units, heat transfer coefficient, dimensionless exergy loss and Witte-Shamsundar efficiency factor. Results presented an increment of 33% and 38% in heat transfer coefficient and Number of Transfer Units, respectively. Maximum value of Witte-Shamsundar efficiency factor was found to be 0.973 and was related to Volume fraction of 0.57 and has occurred at counter flo

    State-of-the-Art Antenna Technology for Cloud Radio Access Networks (C-RANs)

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    The cloud radio access network (C-RAN) is one of the most efficient, low-cost, and energy-efficient radio access techniques proposed as a potential candidate for the implementation of next-generation (NGN) mobile base stations (BSs). A high-performance C-RAN requires an exceptional broadband radio frequency (RF) front end that cannot be guaranteed without remarkable antenna elements. In response, we present state-of-the-art antenna elements that are potential candidates for the implementation of the C-RAN’s RF front end. We present an overview of C-RAN technology and different types of planar antennas operating at the future proposed fifth-generation (5G) bands that may include the following: (i) ultra-wide band (UWB) (3–12 GHz), (ii) 28/38 GHz, and (iii) 60-GHz radio. Further, we propose different planar antennas suitable for the implementation of C-RAN systems. We design, simulate, and optimize the proposed antennas according to the desired specifications covering the required frequency bands. The key design parameters are calculated, analyzed, and discussed. In our research work, the proposed antennas are lightweight, low-cost, and easy to integrate with other microwave and millimeter-wave (MMW) circuits. We also consider different implementation strategies that can be helpful in the execution of large-scale multiple-input multiple-output (MIMO) networks

    Performance comparison of classification algorithms for EEG-based remote epileptic seizure detection in wireless sensor networks

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    Identification of epileptic seizure remotely by analyzing the electroencephalography (EEG) signal is very important for scalable sensor-based health systems.Classification is the most important technique for wide-ranging applications to categorize the items according to its features with respect to predefined set of classes.In this paper, we conduct a performance evaluation based on the noiseless and noisy EEG-based epileptic seizure data using various classification algorithms including BayesNet, DecisionTable, IBK, J48/C4.5, and VFI.The reconstructed and noisy EEG data are decomposed with discrete cosine transform into several sub-bands.In addition, some of statistical features are extracted from the wavelet coefficients to represent the whole EEG data inputs into the classifiers.Benchmark on widely used dataset is utilized for automatic epileptic seizure detection including both normal and epileptic EEG datasets.The classification accuracy results confirm that the selected classifiers have greater potentiality to identify the noisy epileptic disorders

    Antisecretory and antiulcerative effects of ethyl acetate fraction of Nigella sativa (L.) Seed extract in rats

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    The present work was carried out to investigate the possible effects of ethyl acetate seed fraction of Nigella sativa on gastric ulcers and basal gastric secretions using the Non-Steroidal Anti-inflammatory Drug-induced (NSAID) model. Phytochemical screening according to Trease and Evans, 2002 and acute toxicity tests using the Lorke’s Method, 1983 were conducted. For the mucosal integrity study, ulcer and preventive indices were analysed, while volume of gastric juice, titratable acidity, acid output and pepsin concentration were assessed for basal gastric secretion parameters. Phytochemical screening revealed the presence of flavonoids, alkaloids, saponins, glucocinolates amongst others, while the acute toxicity studies revealed a median lethal dose above 5000mg/kg. The rats were grouped into 9 (n = 5), with the extract fraction administered at 50, 100 and 200mg/kg subcutaneously, followed by pyloric ligation with cimetidine used as the standard drug. Five rats received normal saline 1ml/kg/rat subcutaneously (S.C) as Negative Control, Five rats received indomethacin (20 mg/kg S.C), Ten rats for the study of the effect of two different doses of cimetidine 50 and 100 mg/kg S.C (5 rats for each dose). Ten rats for the study of effect of two different doses of cimetidine (50 mg and 100 mg/kg) S.C, given 30 minutes prior to indomethacin administration (5 rats for each dose). The three experimental doses of the extract at 50,100 and 200mg/kg showed a dosedependent decrease in both ulcer and preventive indices with the 200mg/kg dose at 0.6mm and 94% respectively. It also showed a significant (p<0.05) decrease in volume of gastric juice, titratable acidity, acid output and pepsin concentration in dose-dependent manner with the three experimental doses administered with the highest reduction at the 200mg/kg dose. The results obtained suggest that this fraction down-regulated all those parameters which might be attributed to the presence of the phytoconstituents present in this fraction, particularly the flavonoids. Therefore, the extract fraction of this plant possesses gastroprotective activity further explaining the folkloric use of this plant in the therapy of peptic ulcer disease.Keywords: Antiulcerative, Antisecretory, Nigella sativa, Phytochemicals, Rats, Seed Extracts
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