Adaptive optimal control of under-actuated robotic systems using a self-regulating nonlinear weight-adjustment scheme: Formulation and experimental verification

This paper formulates an innovative model-free self-organizing weight adaptation that strengthens the robustness of a Linear Quadratic Regulator (LQR) for inverted pendulum-like mechatronic systems against perturbations and parametric uncertainties. The proposed control procedure is devised by using an online adaptation law to dynamically adjust the state weighting factors of LQR's quadratic performance index via pre-calibrated state-error-dependent hyperbolic secant functions (HSFs). The updated state-weighting factors re-compute the optimal control problem to modify the state-compensator gains online. The novelty of the proposed article lies in adaptively adjusting the variation rates of the said HSFs via an auxiliary model-free online self-regulation law that uses dissipative and anti-dissipative terms to flexibly re-calibrate the nonlinear function's waveforms as the state errors vary. This augmentation increases the controller's design flexibility and enhances the system's disturbance rejection capacity while economizing control energy expenditure under every operating condition. The proposed self-organizing LQR is analyzed via customized hardware-in-loop (HIL) experiments conducted on the Quanser's single-link rotational inverted pendulum. As compared to the fixed-gain LQR, the proposed SR-EM-STC delivers an improvement of 52.2%, 16.4%, 55.2%, and 42.7% in the pendulum's position regulation behavior, control energy expenditure, transient recovery duration, and peak overshoot, respectively. The experimental outcomes validate the superior robustness of the proposed scheme against exogenous disturbances

Surgery for pelvic organ prolapse and stress urinary incontinence and female sexual functions: A quasi-experimental study

Objectives: To assess the effect of pelvic organ prolapse (POP) and/or stress urinary incontinence (SUI) on various domains of female sexual functions in patients before and after reconstructive surgery for these pelvic floor disorders.Methods: We conducted a quasi-experimental study of 126 women aged 25-65 years, presenting with POP / SUI, from January 1st 2019 to December 31st 2019 at Aga Khan University Hospital. POP surgery was performed only in patients with symptomatic POP ≥ stage 2 according to POP-Q (quantification). Sexual functions were assessed using Female Sexual Function Index (FSFI) questionnaire, among sexually active women at baseline and 18 months after surgery.Results: Mean age of the participants was 51.6, with a mean parity of four. Out of 126 patients, 31 patients underwent vaginal hysterectomy, pelvic floor repair and mid-urethral sling (MUS), 55 had vaginal hysterectomy with pelvic floor repair, 12 women had only pelvic floor repair and 10 patients had uterine suspension surgery for prolapse, while 18 patients underwent MUS operation alone for SUI. There was a statistically significant difference in female sexual functions after surgery for POP and/or SUI (p\u3c0.01). This improvement was observed in both total and individual scores of each domain of FSFI with an overall improvement in sexual function from a mean of 18.5 pre-surgery to 20.8 post-surgery.Conclusions: This study reveals that women sexual functions are affected by POP and SUI and improve remarkably after reconstructive surgeries for these pelvic floor disorders

Facial Expression Recognition Based on Deep Learning Convolution Neural Network: A Review

Facial emotional processing is one of the most important activities in effective calculations, engagement with people and computers, machine vision, video game testing, and consumer research. Facial expressions are a form of nonverbal communication, as they reveal a person's inner feelings and emotions. Extensive attention to Facial Expression Recognition (FER) has recently been received as facial expressions are considered. As the fastest communication medium of any kind of information. Facial expression recognition gives a better understanding of a person's thoughts or views and analyzes them with the currently trending deep learning methods. Accuracy rate sharply compared to traditional state-of-the-art systems. This article provides a brief overview of the different FER fields of application and publicly accessible databases used in FER and studies the latest and current reviews in FER using Convolution Neural Network (CNN) algorithms. Finally, it is observed that everyone reached good results, especially in terms of accuracy, with different rates, and using different data sets, which impacts the results

An Investigation of the Relationship between Compulsory Citizenship Behaviour and Psychological Withdrawal

This study used Lazarus and Folkman’s stress and coping theory to develop and test a model of the way employees’ cope with compulsory citizenship behavior at workplace. The model identifies psychological withdrawal as an emotion focused coping behavior. Factor analysis and linear regression were used to analyze the data collected from 368 clerical staff working in four large universities of Faisalabad, Pakistan. Analysis found that employees who experienced frequent compulsory citizenship behavior used psychological withdrawal to cope with it. This study contributes to the limited research on compulsory citizenship behavior at work. Recommendations for future research and implications are discussed

An Investigation of the Relationship between Compulsory Citizenship Behaviour and Psychological Withdrawal

This study used Lazarus and Folkman’s stress and coping theory to develop and test a model of the way employees’ cope with compulsory citizenship behavior at workplace. The model identifies psychological withdrawal as an emotion focused coping behavior. Factor analysis and linear regression were used to analyze the data collected from 368 clerical staff working in four large universities of Faisalabad, Pakistan. Analysis found that employees who experienced frequent compulsory citizenship behavior used psychological withdrawal to cope with it. This study contributes to the limited research on compulsory citizenship behavior at work. Recommendations for future research and implications are discussed

An innovative approach for hyperproduction of cellulolytic and hemicellulolytic enzymes by consortium of Aspergillus niger MSK-7 and Trichoderma viride MSK-10

The present work describes the production of cellulolytic enzymes (CMC-ase, FP-ase, β-glucosidase) and hemicellulolytic enzyme (xylanase) along with total extracellular protein by Aspergillus niger and Trichoderma viride using submerged fermentation. Among seven different kinds of experiments, secretion rate of protein and enzymes was investigated by mono- and co-cultures of A. niger and T. viride using wheat bran as substrate with the supply of Eggins and Pugh salt medium. Co-culture of A. niger and T. viride (when both were mixed together simultaneously) gave 30-50% higher production of total protein (0.58 mg/ml) and enzymes; CMC-ase (2.79 U/ml/min), FP-ase (1.75 U/ml/min) and xylanase (189.7 U/ml/min) than mono-cultures and all other combinations. Biosynthesis of β-glucosidase was found higher i.e., 4.66 U/ml/min in co-culture of A. niger and T. viride (when T. viride was mixed with 24 hours old culture of A. niger). Simultaneous co-culture of A. niger and T. viride was further optimized with fermentation rate, different carbon sources, incubation temperature and different pH of fermentation media.Key words: Strain compatibility, co-culture, mono-culture, fermentation

Performance enhancement of multivariable model reference optimal adaptive motor speed controller using error-dependent hyperbolic gain functions

The main contribution of this paper is to formulate a robust-adaptive and stable state-space speed control strategy for DC motors. The linear-quadratic-integral (LQI) controller is utilized as the baseline controller for optimal speed-regulation, accurate reference-tracking and elimination of steady-state fluctuations in the motor’s response. To reject the influence of modelling errors, the LQI controller is augmented with a Lyapunov-based model reference adaptation system (MRAS) that adaptively modulates the controller gains while maintaining the asymptotic stability of the controller. To further enhance the system’s robustness against parametric uncertainties, the adaptation gains of MRAS online gain-adjustment law are dynamically adjusted, after every sampling interval, using smooth hyperbolic functions of motor’s speed-error. This modification significantly improves the system’s response-speed and damping against oscillations, while ensuring its stability under all operating conditions. It dynamically re-configures the control-input trajectory to enhance the system’s immunity against the detrimental effects of random faults occurring in practical motorized systems such as bounded impulsive-disturbances, modelling errors, and abrupt load–torque variations. The efficacy of the proposed control strategy is validated by conducting credible hardware-in-the-loop experiments on QNET 2.0 DC Motor Board. The experimental results successfully validate the superior tracking accuracy and disturbance-rejection capability of the proposed control strategy as compared to other controller variants benchmarked in this article

Pakistani Physicians: Exploring the Paradox of Public Service Motivation and User Orientation

The desire to support single beneficiary of public services (user orientation) has divergence with desire to support society at large, both motivations compete in same dimensional space. Extra ordinary usage of broad spectrum antibiotics creates negative externalities for society as large because excessive use of antibiotics creates resistance among bacteria that become hard and expensive to cure. There exists large gap to comprehend difference between discrete choices of both motivations of public service. The antibiotics prescriptions behavior of Pakistani general physicians (Doctors) has been analyzed in this study to investigate the association between Public Service Motivation and user orientation with this behavior. 250 Pakistani general practitioners were chosen in both private and public sector to investigate the PSM relationship with user orientation. The findings indicate that there is different association between Public Service Motivation and user orientation regarding prescription behavior of the general physicians (Doctors). This entails that it is necessary to investigate this behavior difference to know whether the public service provider is fascinated towards helping single beneficiary or be concerned more about society

Synthesis and characterization of some new Schiff base derivatives of gabapentin, and assessment of their antibacterial, antioxidant and anticonvulsant activities

Purpose: To synthesize and characterize some new gabapentin Schiff base derivatives, and to assess their antibacterial, antioxidant and antiepileptic activities.Methods: Four Schiff base derivatives of gabapentin, termed G1, G2, G3 and G4, were synthesized by condensation with benzoin, vanillin, acetophenone, and benzophenone, respectively. Their chemical identities were established by FTIR, 1 H NMR and 13C NMR techniques. The new compounds were screened for antibacterial activity using agar well method, antioxidant activity by DPPH assay, and anticonvulsant activity against pentylenetetrazole (PTZ) induced seizures in mice.Results: All the compounds showed antibacterial activity against the test strains to variable degrees, while the parent drug did not exhibit antibacterial activity. The zones of inhibition of compound G2 against Micrococcus luteus (36.2 ± 1.0 mm) and Serratia marcescens (28.2 ± 1.0 mm), and of compound G4 against Stenotrophomonas maltophilia (36.8 ± 1.0 mm) were larger compared to thestandard drug, doxycycline, exhibiting zones of inhibition 28.2 ± 1.3, 28.2 ± 0.9 and 20.0 ± 0.9 mm, respectively. In addition, compounds G1 and G2 possessed significantly greater (p < 0.05) radical scavenging activity (82.3 ± 1.8 and 92.3 ± 2.2 %, respectively) than the precursor drug, gabapentin (63.2± 2.6 %). The seizure scores for compounds G1 (0.7 ± 0.06) and G2 (0.9 ± 0.07) were comparable(p ˃ 0.05) with gabapentin (0.8 ± 0.06), while compounds G3 and G4 were less active (p < 0.05) than gabapentin.Conclusion: Compounds G1 and G2 exhibit good antibacterial and antioxidant activities while retaining the anticonvulsant activity of the parent drug, gabapentin, thus making them suitable candidates for further development for the treatment of neurodegenerative pathologies associated with bacterial infections. Keywords: Gabapentin, Antibacterial, Seizures, Antioxidant, Anticonvulsan