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This article discusses a quantiser-based stabilisation problem for uncertain nonlinear systems with the aid of robust $ \mathcal {[K, KL]} $ [ K , KL ] sector. We confirmed that the quantised-feedback control steers the state trajectories of the uncertain nonlinear systems within the robust $ \mathcal {[K, KL]} $ [ K , KL ] sector in finite time by adjusting the quantisation parameters. Furthermore, control-Lyapunov functions are helpful to obtain sufficient conditions for ensuring the closed-loop system's asymptotic stability and the reachability of the robust $ \mathcal {[K, KL]} $ [ K , KL ] sector. Finally, a nonlinear electronic circuit is provided to test the effectiveness of the designed control law. [ABSTRACT FROM AUTHOR]

This article is concerned with the problem of stabilising nonlinear uncertain systems subject to signal quantisation using nonlinear sector design. The boundary of nonlinear sector decided by the behaviour of the system showing an input-to-state stability is equivalent to $ \mathcal {KL} $ K L -stability. A novel control design based on supervisory-based quantised hands-off control is introduced. With this, the true state of the nonlinear plant is estimated and the quantised control steers the trajectory of the system inside the nonlinear sector in finite time and further to the origin asymptotically. The proposed approach is validated through an illustrative example to demonstrate its theoretical effectiveness. [ABSTRACT FROM AUTHOR]

To describe a concept of ideal 'puncture zone' as against any single ideal 'puncture tract' for percutaneous nephro-lithotomy (PCNL) and present our results. Through this narrative, we aim to reduce the gaps in inter-understanding of an erstwhile description of ideal tract and real-life puncture making. The puncture zone principle was applied for our novel puncture making technique during PCNL. The largest imaginary cone that can fit into a respective calyx, with its tip in the pelvis defines the 'puncture zone' for that calyx. This concept allows fine-tuning of the ideal puncture tract based upon the desired corresponding manipulation zone and also shifts the focus of puncture making to infundibulum anatomy from the tip of calyx. The surgical technique and retrospective review of 136 cases done between 2015 and 2021 using this concept are presented. Primary outcome included stone-free rate, pseudo-aneurysm and blood transfusion at 3 months of follow-up. 33 cases had multiple (> 3) stones, 21 only calyceal/infundibular stones, eight partial staghorn and 12 were complete staghorn stones. Mean stone size was 29 ± 15 (Range: 5–53) mm. Complete clearance was achieved in 127 cases, four of which required two tracts. Blood transfusion was required in one case. No pseudo-aneurysms were encountered. The puncture zone concept has provided good results in our hands. It may help easier understanding of PCN puncture making and provides a background for reconciliation between description of an ideal tract and practical puncturing techniques used by different surgeons. [ABSTRACT FROM AUTHOR]

This paper addresses the invariant [ K , K L ] sector as a special class of [ K , K L ] sector that holds the invariant characteristics with some appropriate control input, i.e. the energy of the system drastically decreases and state trajectory always remains inside the sector once it moves into it by the suitable control signal. The analysis of the nonlinear sector is regarded in comparison function prospective to outreach the property of uniformity. Here, the construction of [ K , K L ] sector and invariant [ K , K L ] sector relies on the selection of well-suited control-Lyapunov function. The switching control with invariant [ K , K L ] sector is designed to ensure the state trajectories move inside the nonlinear sector in finite-time and stay inside for all future time. Finally, the effectiveness of the proposed algorithm is illustrated with real physical examples. [ABSTRACT FROM AUTHOR]

A case study of a 43‑year‑old male without any co‑morbidity presented with acute onset and progressive weakness of bilateral upper and lower limbs. Topics include Fluoro‑deoxy‑glucose positron emission tomography (FDG PET) screening for underlying occult malignancy revealed a solid nodule with circumscribed margins; and possibility of inflammatory myopathy was considered dermatomyositis (DM) or viral myositis.

Lower urinary tract symptoms in females can be due to various factors. Most of the time it is due to simple urinary tract infection and lower urinary tract pathology such as urethral stricture, meatal stenosis, bladder stones, underactive detrusor, and primary bladder neck obstruction. Commonly found neurologic causes among females are detrusor–external sphincter dyssynergia, associated with various brain and spine diseases and diabetic neuropathy. Labial fusion is a rare cause of female voiding difficulty. We herein present two elderly postmenopausal diabetic female patients who had nearly total urethral occlusion due to labial fusion. After thorough history taking and local genitourinary examination, the patients were operated. Treatment included surgical correction followed by the local application of 1% estrogen ointment. Both patients were symptom-free after the procedure. Thus, with a correct diagnosis followed by simple operative procedure, we can treat such patients successfully. [ABSTRACT FROM AUTHOR]

In this article, an implicit Euler algorithm for digital implementation of constrained stabilization is studied for the second‐order systems. For that, a switching controller is designed in a discrete‐time framework such that the system's position output converges to some predefined range, that is, ϱ ∈ (−ε, ε) in finite‐time while the velocity output converges to the origin, that is, ϱ˙=0, in finite‐time. The switching controller is switched to the implicit Euler implementation of twisting algorithm when ϱ ∉ (−ε, ε) and to an implicit Euler implementation of first‐order sliding mode control when ϱ ∈ (−ε, ε). The combination of the two implicit Euler implementations achieves discrete‐time constrained stabilization of second‐order systems, avoiding the chattering caused by conventional explicit integration schemes. The usefulness of the proposed algorithm for constrained stabilization is illustrated by considering the container‐slosh coupled dynamical system. [ABSTRACT FROM AUTHOR]

This paper addresses a quantized feedback hands‐off control for a class of nonlinear systems. Here, [K,KL] sector is constructed with the suitable choice of control‐Lyapunov function. With adjustment policy of quantization parameters, the quantized feedback hands‐off control can force the states of the nonlinear feedback system to the interior of a continuous‐time [K,KL] sector infinite time and the Lyapunov‐candidate function decreases automatically inside the designed sector. Finally, the effectiveness of the proposed method is illustrated by numerical examples. [ABSTRACT FROM AUTHOR]

Summary: This article presents a hands‐off control design for discrete‐time nonlinear system with a special type of nonlinear sector termed as "discrete‐time [𝒦,𝒦ℒ] sector." The design method to define the boundary of a discrete‐time [𝒦,𝒦ℒ] sector is done with control‐Lyapunov function. The generalization of nonlinear system is viewed in the perspective of a comparison function. By means of a proposed sector, a switching control is designed such that no control action is experienced inside the sector thus, saving unnecessary control efforts. However, to study the robustness for discrete‐time system, a hands‐off control is modified to ensure the monotonic decrease in the energy of the system. Finally, the proposed approach is verified with the simulation results. [ABSTRACT FROM AUTHOR]

This paper addresses the problem of traditional sliding mode control design subject to the mismatched disturbance. Existing methods fail to provide an efficient and simple solution. To counteract the unmatched disturbance in the system, a new sliding mode control strategy based on a non-smooth integral sliding manifold is proposed. The proposed sliding manifold has two important features. First, it acts like a reduced order disturbance observer since it estimates the mismatched disturbances by itself without any requirement of an additional observer design. Secondly, the system always starts from the sliding surface, hence, there is no reaching phase dynamics. Thus, the system trajectory is insensitive towards the disturbance from the initial point. The proposed method is tested on a coupled tank system to demonstrate its effectiveness. Both the simulation and experimental results are provided. • A non-smooth integral sliding manifold is proposed with modified sliding mode control design. • Act as reduced order disturbance observer to estimate mismatched disturbances without any additional observer design. • System trajectory is insensitive towards the disturbance as there is no reaching phase dynamics. • Proposed work is tested on a coupled tank system to demonstrate its effectiveness. [ABSTRACT FROM AUTHOR]

Peutz-Jeghers syndrome (PJS) is an autosomal dominant disorder characterized by intestinal hamartomatous polyps in association with skin and mucosal macular melanin deposition. There is a lifetime chance of 93% of cancers when all cancers are combined and the incidence of the disease is variable between 1 in 8300 and 1 in 280,000 live births (Daniell et al., Familial Cancer 17(3):421-427, 2018). Here, we present a 14-year-old Indian boy presenting to surgical emergency with intestinal obstruction secondary to jejunojejunal intussusception for which resection and anastomosis were done. Post-operative histopathological examination showed a single polyp leading to intussusception. He classically showed mucocutaneous pigmentation on general examination. Early identification of Peutz-Jeghers syndrome on a routine visit to healthcare can decrease complications like intestinal obstruction and help in starting early surveillance for cancers. [ABSTRACT FROM AUTHOR]

Horseshoe kidney is a rare congenital anomaly resulting from the fusion of the lower pole leading to medial and caudal deviation of kidneys that pose challenges to successful stone clearance. We evaluated the various patient- and treatment-related factors that can impact successful stone clearance. A total of 34 patients with 36 renal moieties with urolithiasis in horseshoe kidneys from 2015 to 2021 were included with a median age of 38 years (11–56 years). The mean calculus size was 39.27 mm (21–70 mm). Twenty-two patients had left, 10 had right, and 2 had bilateral disease. Twelve patients (33%) had previous interventions done. As per Guy stone score (GSS), 14 patients had grade IV, 16 patients had grade III, and 4 patients had grade II disease. Of these patients, 22 underwent unilateral percutaneous nephrolithotomy (PCNL), 2 underwent bilateral PCNL, 6 had pyelolithotomy, 2 had right nephrectomy, and 2 patients underwent shockwave lithotripsy (SWL). Six patients undergoing pyelolithotomy had complete clearance. In PCNL, infra-costal puncture was done uniformly. Complete clearance was seen in 12 out of 16 with superior calyceal access (75% stone-free rates, SFR), 2 out of 8 with middle calyceal puncture (25% SFR), and both the cases with inferior calyceal puncture (100% SFR). Factors affecting stone clearance are as follows: GSS, i.e., grade < IV vs ≥ IV (71.4 vs 50%, P = 0.42), STONE score < 12 vs ≥ 12 (83.3 vs 28.5%, P = 0.048), stone size < 40 vs ≥ 40 mm (50 vs 71.4%, P = 0.42). Our analysis showed that stone clearance was independent of mode of access, GSS, or stone size, although STONE score was a predictor of successful outcomes in PCNL. [ABSTRACT FROM AUTHOR]

This paper introduces a new approach to designing a disturbance observer called a modified extended state observer (ESO). The existing ESO technique ensures that the trajectories of estimation error dynamics globally asymptotically converge to zero in the absence of time varying disturbances. However, for perturbed systems, where time varying disturbances affect system behavior, these trajectories never reach zero but rather remain bounded around the origin within a constant value. Consequently, this discrepancy leads to challenges in accurately estimating state trajectories and discerning information about disturbances. This, in turn, complicates the precise estimation of state dynamics and disturbances and poses difficulties in designing control laws for stability analysis of the system. Unlike existing ESO methods, the distinguishing characteristic of this modified ESO is its capability to achieve global and asymptotic convergence of observation error in the presence of unknown bounded time varying disturbances. This unique property enables the exact estimation of state trajectories. Information about the bounded time varying disturbances is obtained and significantly attenuate more efficiently compared to existing ESO techniques. Based on the estimated disturbances, any classical controller can be designed for the system to achieve set-point tracking subject to time varying disturbances. To validate the performance of the proposed modified ESO, the model of a coupled-tank setup is simulated for the stabilization problem and its experimental setup is demonstrated for the tracking problem. For carrying out the experiment on a real-time hardware setup, an input of step change at every 60 s with water level variation of ± 2 cm from initial set value of 15 cm to achieve the set-point tracking of the water levels in the both the tanks along with good transient performance in the presence of time-varying external disturbances. • Development of modified extended state observer in presence of unknown disturbances. • The observation error converges to zero globally and asymptotically. • Achieves higher accuracy for disturbance estimation and complete elimination. • Proposed work is tested on a coupled tank system to demonstrate its effectiveness. [ABSTRACT FROM AUTHOR]

In the past mooring chain failure probabilities have been much higher than the design failure probabilities. The high failure rates are attributed to prolonged exposure to various degradation mechanisms in harsh offshore conditions. In addition to understanding failure mechanisms, researchers have stressed on reducing the risk of failures through regular and reliable inspections. Current inspection techniques involve both in-air and in-water inspections. However, current in-air inspections are time consuming and expensive, while in-water inspection techniques are not yet reliable. The present paper proposes a condition monitoring and strength estimation methodology based on three-dimensional (3D) scans of links. The study first identifies and estimates changes in simple geometrical features of chain links using finite element (FE) modeling for condition monitoring. The methodology has two stages: 3D general imaging (3D-GI) to identify degraded chain links using feature monitoring, followed by 3D detailed imaging (3D-DI) of the identified weak links. The weak links 3D point clouds could be further converted to solid FE models for residual strength estimation by employing a suitable material degradation model. The geometrical feature monitoring methodology is verified by 3D scans of an undeformed and a deformed studded link. • In-water three-dimensional (3D) imaging for condition assessment of mooring chains. • Identification of geometrical features which could be monitored during the underwater 3D inspections. • Scanning of chain links to generate 3D point clouds and conversion to solid Finite Element (FE) models for analysis. • Strength estimation of degraded chain links using FE models generated using 3D point cloud data. [ABSTRACT FROM AUTHOR]

Mooring chains in many offshore floating facilities have failed due to overloading under extreme environmental events. The ductile failure in chains due to overloading has not been addressed in past studies. Therefore, the present study aims to analyze the ductile failure in chain links using micromechanics and phenomenology based numerical models. The material damage model parameters are established using material stress-strain plots obtained from tensile tests on coupons, extracted from a R3 grade steel chain link. The validation of material degradation models is achieved by comparing results from numerical studies and monotonic loading tests on mooring chain links of 76 mm nominal diameter. The material models successfully capture the failure mode and strength of the chain links. • Non-linear behavior estimation of 76 mm stud chain specimens of R3 grade steel using monotonic loading tests. • Material strength tests on tensile coupon specimens extracted from R3 grade steel stud chain link. • Identification and calibration of micromechanics and phenomenology based material failure models. • Use of material damage models in conjunction with elastic-plastic material definition established using material tests. • ABAQUS/Explicit analysis is utilized for ductile fracture modeling in the stud chain links. [ABSTRACT FROM AUTHOR]

This paper proposes a distributed artificially delayed output feedback‐based leader–follower and leaderless consensus control for the uncertain general linear multiagent systems (MASs) with an arbitrary relative degree. Based on the measured relative output and their delayed information with respect to neighbours, two distributed controllers are designed, which relaxes the requirement of all relative states information of agents. Through the Lyapunov–Krasovskii functional, linear matrix inequalities (LMIs) are formulated, and these LMIs are feasible for arbitrary small delays selected by the user. Delay‐dependent sufficient conditions are provided to guarantee the asymptotic convergence of nominal error systems and ultimately uniform boundedness in the case of a perturbed error system, using the input to state stability (ISS) theory. Finally, the efficacy of the proposed method is illustrated through numerical examples. [ABSTRACT FROM AUTHOR]

The application of microgrids (MG) has a vital role in grid modernization. However, a larger number of installations of electronically coupled distributed energy resources (DER) units in MGs have created opportunities and threats for grid operations. Therefore, efficient and reliable control strategies for MG operation are essential. This article introduces the concept of sector design to show the stabilization of voltage source converter-interfaced DER units in MG applications. The sliding sector design is advanced sliding mode control to obtain a region of attraction such that the state space is divided into attractive and nonattractive regions. In addition, a variable structure-based controlling method has been introduced to drive the trajectories of a plant from the exterior to the interior of the sector and strictly inside throughout the process. In autonomous MG operation, the proposed controller focuses on stabilizing the electronically coupled DER unit's voltage and frequency response. Besides, it confirms the safety of the power conversion system from external disturbances. The system stability is proven using the Lyapunov candidate function. The proposed strategy has been effectively validated through PSCAD/EMTDC. The simulation results have examined the impact of balanced, unbalanced, nonlinear, and dynamic loading patterns in islanded MG. [ABSTRACT FROM AUTHOR]

Numerous studies have been done for markers of lung injury especially in animal models and it remains relatively unexplored whether these biomarkers clinically correlate with the outcome of patients or with the extent of lung parenchymal injury as deduced by MDCT. This prospective study was conducted to assess the serum level of Clara cell secretory protein (CC16) and volume of the uninvolved lung by MDCT and to ascertain the correlation between levels of CC16 with the volume of the injured lung in the clinical outcome of patients of blunt thoracic trauma. Serum CC16 levels and mean uninvolved lung volumes of both lungs were compared in between groups of eventless recovery, need for mechanical ventilation and mortality with p value < 0.05 considered to be significant. Sixty-two patients of blunt chest trauma, age range from 18 to 60 years, were evaluated in our study. Out of them, 43 (69%) were male. Higher level (more than 100 ng/mL) of serum Clara cell protein was associated with the requirement of ventilator and mortality. Total mean uninvolved lung volume of 1075.71 ± 327.5 and 2329.23 ± 776.01 was significantly associated with the requirement of mechanical ventilation and eventless recovery of patients respectively. A mild negative correlation (− 0.4) between the remaining volume of the lung after injury and serum Clara cell protein levels were also noted. Serum CC16 levels may obviate the need of MDCT in the selected group of patients and thereby avoiding its radiation hazards. [ABSTRACT FROM AUTHOR]