NON-LINEAR MODEL PREDICTIVE CONTROL STRATEGIES FOR PROCESS PLANTS USING SOFT COMPUTING APPROACHES

The developments of advanced non-linear control strategies have attracted a considerable research interests over the past decades especially in process control. Rather than an absolute reliance on mathematical models of process plants which often brings discrepancies especially owing to design errors and equipment degradation, non-linear models are however required because they provide improved prediction capabilities but they are very difficult to derive. In addition, the derivation of the global optimal solution gets more difficult especially when multivariable and non-linear systems are involved. Hence, this research investigates soft computing techniques for the implementation of a novel real time constrained non-linear model predictive controller (NMPC). The time-frequency localisation characteristics of wavelet neural network (WNN) were utilised for the non-linear models design using system identification approach from experimental data and improve upon the conventional artificial neural network (ANN) which is prone to low convergence rate and the difficulties in locating the global minimum point during training process. Salient features of particle swarm optimisation and a genetic algorithm (GA) were combined to optimise the network weights. Real time optimisation occurring at every sampling instant is achieved using a GA to deliver results both in simulations and real time implementation on coupled tank systems with further extension to a complex quadruple tank process in simulations. The results show the superiority of the novel WNN-NMPC approach in terms of the average controller energy and mean squared error over the conventional ANN-NMPC strategies and PID control strategy for both SISO and MIMO systemsPetroleum Training Development Fun

Evaluation of Jaundice meter in the assessment of jaundice among Nigerian preterm neonates

Background: The objective assessment of the severity of neonatal jaundice is Total Serum Bilirubin (TSB) determination, which requires multiple blood sampling. This has inherent problems, including risks of anaemia and infection. Transcutaneous Bilirubinometry (TcB) is a reliable, non-invasive alternative, however there is paucity of data on its performance in black preterm neonates.Objectives: To evaluate the correlation between transcutaneous bilirubin (TcB) and total serum bilirubin (TSB) among Nigerian preterm neonates, and to determine the parameters affecting the relationship.Method: Jaundiced preterm neonates delivered between 28 and 36 weeks of gestation admitted at the Irrua Specialist Teaching Hospital (ISTH), Nigeria were recruited . The TSB levels were determined by spectrophotometry while the corresponding TcB levels were obtained using Jaundice Meter (JM-103). The neonates were stratified into gestational age and birth weight groups.Results: A total of 189 paired TcB and TSB levels were obtained from 60 neonates. The Mean (sd) TcB level of 11.4 (3.1) mg/dl was significantly higher than the mean TSB level of 10.2 (2.8)mg/dl (p= 0.028). The overall correlation coefficient between TcB and TSB was 0.98 and it was not significantly affected by the gestational age, birth weight and bilirubin levels.Conc lusion: Transcutneous bilirubin strongly correlates with total serum bilirubin levels among Nigerian preterm neonates, irrespective of gestational age, birth weight and the degree of jaundice.Keywords: hyperbiliruinaemia, jaundice meter, Nigerian, preterm, neonates, transcutaneous bilirubinometr

Taguchi based Design of Sequential Convolution Neural Network for Classification of Defective Fasteners

Fasteners play a critical role in securing various parts of machinery. Deformations such as dents, cracks, and scratches on the surface of fasteners are caused by material properties and incorrect handling of equipment during production processes. As a result, quality control is required to ensure safe and reliable operations. The existing defect inspection method relies on manual examination, which consumes a significant amount of time, money, and other resources; also, accuracy cannot be guaranteed due to human error. Automatic defect detection systems have proven impactful over the manual inspection technique for defect analysis. However, computational techniques such as convolutional neural networks (CNN) and deep learning-based approaches are evolutionary methods. By carefully selecting the design parameter values, the full potential of CNN can be realised. Using Taguchi-based design of experiments and analysis, an attempt has been made to develop a robust automatic system in this study. The dataset used to train the system has been created manually for M14 size nuts having two labeled classes: Defective and Non-defective. There are a total of 264 images in the dataset. The proposed sequential CNN comes up with a 96.3% validation accuracy, 0.277 validation loss at 0.001 learning rate.Comment: 13 pages, 6 figure

Persistent hypertension up to one year postpartum among women with hypertensive disorders in pregnancy in a low-resource setting:A prospective cohort study

BACKGROUND: Hypertensive disorders in pregnancy (HDPs) are associated with lifelong cardiovascular disease risk. Persistent postpartum hypertension in HDPs could suggest progression to chronic hypertension. This phenomenon has not been well examined in low- and middle-income countries (LIMCs), and most previous follow-ups typically last for maximally six weeks postpartum. We assessed the prevalence of persistent hypertension up to one year in women with HDPs in a low resource setting and determined associated risk factors. METHODOLOGY: A prospective cohort study of women conducted at eight tertiary health care facilities in seven states of Nigeria. Four hundred and ten women with any HDP were enrolled within 24 hours of delivery and followed up at intervals until one year postpartum. Descriptive statistics were performed to express the participants’ characteristics. Univariable and multivariable logistic regressions were conducted to identify associated risk factors. RESULTS: Of the 410 women enrolled, 278 were followed up to one year after delivery (follow-up rate 68%). Among women diagnosed with gestational hypertension and pre-eclampsia/eclampsia, 22.3% (95% CI; 8.3–36.3) and 62.1% (95% CI; 52.5–71.9), respectively, had persistent hypertension at six months and this remained similar at one year 22.3% (95% CI; 5.6–54.4) and 61.2% (95% CI; 40.6–77.8). Maternal age and body mass index were significant risk factors for persistent hypertension at one year [aORs = 1.07/year (95% CI; 1.02–1.13) and 1.06/kg/m(2) (95% CI; 1.01–1.10)], respectively. CONCLUSION: This study showed a substantial prevalence of persistent hypertension beyond puerperium. Health systems in LMICs need to be organized to anticipate and maintain postpartum monitoring until blood pressure is normalized, or women referred or discharged to family physicians as appropriate. In particular, attention should be given to women who are obese, and or of higher maternal age

Metabolic syndrome following hypertensive disorders in pregnancy in a low-resource setting:A cohort study

Objectives: Hypertensive disorders in pregnancy (HDPs) are associated with risk of future metabolic syndrome. Despite the huge burden of HDPs in sub-Saharan Africa, this association has not been adequately studied in this population. Study design: This was a prospective cohort study on pregnant women recruited between August 2017 - April 2018 and followed up to one year after their deliveries and evaluated for presence of metabolic syndrome at delivery, nine weeks, six months and one year. Main outcome measures: Prevalence of metabolic syndrome Results: A total of 488 pregnant women were included: 410 and 78 with HDPs and normotensive, respectively. None of the normotensive had metabolic syndrome until one year (1.7% = 1 out of 59 observations), while among those with HDPs were 17.4% (71 of 407), 8.7% (23 of 263), 4.7% (11 of 232) and 6.1% (17 of 278), at delivery, nine weeks, six months and one year postpartum, respectively. High BMI and blood pressure were the drivers of metabolic syndrome in this population. The incidence rate in HDPs versus normotensive at one year were, respectively, 57.5/1000 persons’ year (95%CI; 35.8 – 92.6) and 16.9/1000 persons’ years (95%CI; 2.4-118.3), with incidence rate ratio of 3.4/1000 person's years. Only parity significantly predicted the presence of metabolic syndrome at one year [(aOR= 3.26/delivery (95%CI; 1.21-8.79)]. Conclusion: HDPs were associated with a higher incidence of metabolic syndrome up to one year postpartum. Women with HDPs should be routinely screened for metabolic syndrome within the first year postpartum to reduce cardiometabolic risks.</p

Adherence to Guidelines in Postpartum Management of Hypertensive Disorders in Pregnancy in Tertiary Health Facilities in Nigeria: A Multi-centre Study

Hypertensive disorders in pregnancy (HDPs) are a leading cause of maternal morbidity and mortality. Available guidelines for their postpartum management are expected to be optimally utilized. This study aimed to determine adherence to guidelines in selected Nigerian tertiary hospitals. It was nested in a cohort of women with HDPs who delivered in eight facilities between October 2017 and June 2018. Nine weeks after delivery, their cases were evaluated on prespecified indicators and supplemented with interviews. The level of adherence to the guidelines was determined using descriptive analyses, including frequencies, percentages, means, and standard deviations, as well as charts. Of the 366 participants, 33 (9%), 75 (20%), 200 (55%), and 58 (16%) had chronic hypertension, gestational hypertension, preeclampsia, and eclampsia, respectively. Only about a third had their blood pressure measured between postpartum days three and five. Similarly, a third of those with persistent hypertension (≥140/90 mmHg) were not on antihypertensive medications within the first week postpartum. In addition, 37% and 42% of participants were not counseled on contraceptives and early subsequent antenatal visits, respectively. Among those with preeclampsia/eclampsia, 93% were not offered postpartum screening for thromboprophylaxis. Although all women with preeclampsia/eclampsia remained hypertensive two weeks after discharge, only 24% had medical reviews. Overall, only 58% and 44% of indicators were adhered to among all HDPs and preeclampsia/eclampsia-specific indicators, respectively. Level of adherence to guidelines on postpartum management of HDPs in Nigerian tertiary hospitals is poor. It is recommended that institutionalization of guidelines be prioritized and linked to the entire continuum from preconception through longer term postpartum care

Metabolic syndrome following hypertensive disorders in pregnancy in a low-resource setting: A cohort study

Objectives: Hypertensive disorders in pregnancy (HDPs) are associated with risk of future metabolic syndrome. Despite the huge burden of HDPs in sub-Saharan Africa, this association has not been adequately studied in this population. Study design: This was a prospective cohort study on pregnant women recruited between August 2017 - April 2018 and followed up to one year after their deliveries and evaluated for presence of metabolic syndrome at delivery, nine weeks, six months and one year. Main outcome measures: Prevalence of metabolic syndrome Results: A total of 488 pregnant women were included: 410 and 78 with HDPs and normotensive, respectively. None of the normotensive had metabolic syndrome until one year (1.7% = 1 out of 59 observations), while among those with HDPs were 17.4% (71 of 407), 8.7% (23 of 263), 4.7% (11 of 232) and 6.1% (17 of 278), at delivery, nine weeks, six months and one year postpartum, respectively. High BMI and blood pressure were the drivers of metabolic syndrome in this population. The incidence rate in HDPs versus normotensive at one year were, respectively, 57.5/1000 persons’ year (95%CI; 35.8 – 92.6) and 16.9/1000 persons’ years (95%CI; 2.4-118.3), with incidence rate ratio of 3.4/1000 person's years. Only parity significantly predicted the presence of metabolic syndrome at one year [(aOR= 3.26/delivery (95%CI; 1.21-8.79)]. Conclusion: HDPs were associated with a higher incidence of metabolic syndrome up to one year postpartum. Women with HDPs should be routinely screened for metabolic syndrome within the first year postpartum to reduce cardiometabolic risks