An improved model predictive control of back-to-back three-level NPC converters with virtual space vectors for high power PMSG-based wind energy conversion systems.

In this study, an improved virtual space vector (VSV)-based two-stage model predictive control (MPC) scheme is presented for neutral point clamped (NPC) converters in high power-rated permanent magnet synchronous generator (PMSG)-based wind energy conversion system applications. The presented MPC scheme utilizes the VSVs and involves two-stage prediction for effectively reducing computation complexity. In stage-I prediction, a virtual space vector is identified based on the optimum cost function. Then, a set of sub-sector vectors are placed in stage II prediction based on the capacitor voltage levels. From this, the cost function predicts the optimum switching state. At the same time, the conditional selection of small voltage vectors in stage II prediction eliminates the neutral point voltage balancing constraint. Finally, the presented method is verified by the simulation of the back-to-back NPC converter of a high-power-rated PMSG-based wind energy conversion system. Further, the adaptability of the presented scheme for maximum power point tracking, reactive power control, and dc-link voltage control is also verified by simulation.

Stabilization analysis of fractional-order nonlinear permanent magnet synchronous motor model via interval type-2 fuzzy memory-based fault-tolerant control scheme.

The main objective of this study is to improve the convergence rate performance and analyze the stability properties of the FOPMSM model considering the load-torque external disturbances and actuator faults. Due to the complex nonlinearity, the presented FONPMSM model in the d-q frame is approximated by an IT-2 T-S fuzzy modeling technique. Besides, the fuzzy memory-based FTC is designed to eliminate the typical characteristics of chaotic behaviors and stabilize the proposed nonlinear model even if load torque disturbances, actuator faults in the controller, and time delays occur. Further, by employing the fractional order-based fuzzy LKF, some sufficient conditions are carried out in terms of LMIs to guarantee the asymptotic stability conditions, and simultaneously, disturbance reduction is confirmed. And then, the desired control gain matrices are determined from solvable LMIs, which can help to enhance the system stability performance. Finally, the numerical simulation of T-S fuzzy-based FOPMSM model is given to validate the applicability and efficiency of the proposed controller.

Learning dynamic spatial-temporal regularized correlation filter tracking with response deviation suppression via multi-feature fusion.

Visual object tracking (VOT) for intelligent video surveillance has attracted great attention in the current research community, thanks to advances in computer vision and camera technology. Meanwhile, discriminative correlation filter (DCF) trackers garnered significant interest owing to their high accuracy and low computing cost. Many researchers have introduced spatial and temporal regularization into the DCF framework to achieve a more robust appearance model and further improve tracking performance. However, these algorithms typically set fixed spatial and temporal regularization parameters, which limit flexibility and adaptability under cluttered and challenging scenarios. To overcome these problems, in this work, we propose a new dynamic spatial-temporal regularization for the DCF tracking model that emphasizes the filter to concentrate on more reliable regions during the training stage. Furthermore, we present a response deviation-suppressed regularization term for responses to encourage temporal consistency and avoid model degradation by suppressing relative response changes between two consecutive frames. Moreover, we introduce a multi-memory tracking framework to exploit various features and each memory contributes to tracking the target across all frames. Significant experiments on the OTB-2013, OTB-2015, TC-128, UAV-123, UAVDT, and DTB-70 datasets have revealed that the performance thereof outperformed many state-of-the-art trackers based on DCF and deep-based frameworks in terms of tracking accuracy and tracking success rate.

Association of Metabolic Syndrome with the Risk of Head and Neck Cancer: A 10-Year Follow-Up Study of 10 Million Initially Healthy Individuals.

The aim of this national population-based retrospective study was to analyze the relationship between MetS and the incidence of HNC. In this Korean population-based cohort study, 9,598,085 subjects above the age of 20 were monitored from 1 January 2009 to 31 December 2018. In the study population, a total of 10,732 individuals were newly diagnosed with HNC during the 10-year follow-up. The hazard ratio (HR), after adjusting for age, gender, smoking status, alcohol intake, and exercise, indicated that participants with MetS were at a 1.06-fold (95% CI: 1.01-1.10) higher risk of having HNC than those without MetS. Participants with MetS showed an increased risk of developing oral cavity cancer (HR, 1.12; 95% CI, 1.03-1.23) and laryngeal cancer (HR, 1.18; 95% CI, 1.09-1.27). Among the components of MetS, elevated fasting glucose (HR = 1.04, 95% CI: 1.00-1.08) and elevated blood pressure (HR = 1.08, 95% CI: 1.04-1.13) were significantly associated with an increased HR for HNC in an adjusted multivariable model. The association between HNC and MetS remained significant even among individuals who had never smoked or were ex-smokers (HR: 1.09; 95% CI: 1.04-1.15), as well as those who did not drink or were mild drinkers (HR: 1.07; 95% CI: 1.02-1.12). The findings of this cohort study suggest MetS was associated with an increased risk for some types of HNCs. The results of this study could assist with etiological investigations and prevention strategies.

Decentralized Sampled-Data Control for Stochastic Disturbance in Interconnected Power Systems With PMSG-Based Wind Turbines.

The presented work is concerned with the stability performance of frequency response for interconnected power systems (IPSs) with permanent magnet synchronous generator (PMSG)-based wind turbines (WTs) via a decentralized control scheme against external and stochastic disturbances. To do this, initially, the state-space model is derived when a PMSG is penetration into IPSs. Differing from existing works, IPSs with PMSG-based WTs, including the stochastic disturbance, are modeled as a stochastic state-space model. Then, decentralized sampled-data load frequency control is designed to regulate the frequency response of the proposed model against the deterministic and stochastic noises. By constructing bilateral looped Lyapunov functional and using Itôs formula, stochastic sufficient conditions are derived, which ensure that the closed-loop form of the proposed model is asymptotically stable in the mean square with H∞ performance index γ . Finally, three-area IPSs with PMSG-based WTs are validated with derived sufficient conditions. The simulation results confirmed the better-stability performance of frequency response for the proposed stochastic IPSs with PMSG-based WTs.

Formation Control and Tracking of Mobile Robots using Distributed Estimators and A Biologically Inspired Approach.

This paper investigates the formation control problem for multiple nonholonomic wheeled mobile robots using distributed estimators and a biologically inspired approach. The formation pattern of the system adopts leader-follower structure and the communication topology among the multi-robot system is modelled by an undirected graph. In our proposed methodology, first, we develop an adaptive trajectory tracking control for the leader robot to follow the desired trajectory. Second, a distributed estimator is designed for each follower mobile robot, which uses its own information to estimate the leader's states, such as position, orientation, and linear velocity. Then, distributed formation tracking control laws are designed based on the distributed estimator. Furthermore, a bioinspired controller is developed to address the impractical velocity jump problem. The closed-loop system stability is analysed with the Lyapunov stability theory showing that tracking errors are asymptotically converge to zero. Finally, simulation results are provided to demonstrate the effectiveness of the proposed methods.

Oncological and functional outcomes of partial or total laryngopharyngectomy for hypopharyngeal cancer with thyroid or cricoid cartilage invasion.

BACKGROUND: Patients with cartilage invasion in hypopharyngeal squamous cell carcinoma (HPSCC) would benefit from partial laryngopharyngectomy (PLP). AIMS/OBJECTIVES: The purpose of this study was to examine the treatment outcomes of PLP for HPSCC with cartilage invasion, with a focus on the oncological safety and the function preservation. MATERIALS AND METHODS: We performed a retrospective review of 28 patients with HPSCC with thyroid or cricoid cartilage invasion who had undergone upfront surgery and were followed for more than one year between 1993 and 2019. RESULTS: Twelve patients treated with PLP (42.9%) and 16 patients treated with total laryngopharyngectomy (TLP) for cartilage invasion in HPSCC were identified. There was no significant difference in recurrence between the PLP group (7/12, 58.3%) and the TLP group (8/16, 50.0%) (p = .718). PLP was not associated with decreased five-year disease free survival (p = .662) or disease specific survival (p = .883) rates compared to TLP. Nine patients receiving PLP could be decannulated and retained intelligible speech (9/12, 75%). Gastrostomy tubes were placed in the PLP group (5/12, 42.9%) and TLP group (1/16, 6.2%) (p = .057). CONCLUSIONS AND SIGNIFICANCE: PLP appears to be a feasible option for the treatment of thyroid or cricoid cartilage invasion in HPSCC.

Predictive factors of distant metastasis in surgically treated HPV-positive tonsil cancer.

BACKGROUND: Human papilloma virus (HPV)-related tonsil cancer is associated with favorable outcomes. OBJECTIVE: The purpose of this study was to define factors affecting distant metastasis in patients with surgically treated HPV-positive tonsil cancer. METHODS: The present study enrolled 76 patients diagnosed with HPV-positive tonsil cancer who underwent primary surgery between January 2010 and December 2021. RESULTS: Twelve (15.7%) patients experienced a distant failure with a median follow-up time of 43 months. Sites of distant metastasis included the lung (n = 10), liver (n = 1), and brain (n = 1). Upon multivariate analysis, an advanced T stage (odds ratio [OR]: 13.94, 95% confidence interval [CI]: 1.29-149.863, p = 0.003) and margin involvement (OR: 5.96, 95% CI: 1.33-26.76, p = 0.02) were independent predictors of distant metastases. The five-year disease-specific survival for the entire cohort was 85%. The multivariate analysis confirmed that distant metastasis (hazard ratio [HR]: 12.688, 95% CI: 3.424-47.016; p < 0.001) and margin involvement (HR: 6.243; 95% CI: 1.681-23.191; p = 0.006) were significant factors associated with the five-year disease-specific survival. CONCLUSION: HPV-positive tonsil cancer patients with an advanced T stage and a positive surgical margin have a substantial risk of distant metastases. Distant metastasis and margin involvement are factors that affect their survival.

Guideline for the Surgical Management of Locally Invasive Differentiated Thyroid Cancer From the Korean Society of Head and Neck Surgery.

The aim of this study was to develop evidence-based recommendations for determining the surgical extent in patients with locally invasive differentiated thyroid cancer (DTC). Locally invasive DTC with gross extrathyroidal extension invading surrounding anatomical structures may lead to several functional deficits and poor oncological outcomes. At present, the optimal extent of surgery in locally invasive DTC remains a matter of debate, and there are no adequate guidelines. On October 8, 2021, four experts searched the PubMed, Embase, and Cochrane Library databases; the identified papers were reviewed by 39 experts in thyroid and head and neck surgery. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess the quality of evidence, and to develop and report recommendations. The strength of a recommendation reflects the confidence of a guideline panel that the desirable effects of an intervention outweigh any undesirable effects, across all patients for whom the recommendation is applicable. After completing the draft guidelines, Delphi questionnaires were completed by members of the Korean Society of Head and Neck Surgery. Twenty-seven evidence-based recommendations were made for several factors, including the preoperative workup; surgical extent of thyroidectomy; surgery for cancer invading the strap muscles, recurrent laryngeal nerve, laryngeal framework, trachea, or esophagus; and surgery for patients with central and lateral cervical lymph node involvement. Evidence-based guidelines were devised to help clinicians make safer and more efficient clinical decisions for the optimal surgical treatment of patients with locally invasive DTC.

Role of local flaps in the prevention of soft tissue necrosis after transoral robotic surgery for tonsillar cancer.

OBJECTIVE: Soft tissue necrosis (STN) can occur after transoral robotic surgery (TORS) with radiation therapy (RT). We investigated the usefulness of local flap reconstruction for preventing STN after TORS in patients with tonsillar cancer. METHODS: This case-control study retrospectively reviewed clinicopathological data of patients who underwent TORS for tonsillar cancer at a tertiary referral center. The incidence of STN was compared in patients who underwent secondary intention healing or local flap reconstruction, and factors predicting STN were identified. RESULTS: STN occurred in 20 (25%) of 80 patients in the study. The incidence of STN was higher in the secondary intention healing than the flap reconstruction group. Mucositis grade (odds ratio [OR] 3.694, p = 0.02), RT dose (OR 4.667, p = 0.001), and secondary intention healing (OR 14.985, p = 0.035) were predictive factors for STN. CONCLUSION: Flap reconstruction can prevent STN after TORS with RT in patients with tonsillar cancer. The use of local flaps preserves the minimally invasive nature of TORS.

Association of dietary factors with noise-induced hearing loss in Korean population: A 3-year national cohort study.

Noise-induced hearing loss (NIHL) is a hearing impairment (HI) caused by various clinical factors. Identifying the relationship between NIHL and nutrient consumption could help in reducing the prevalence of hearing loss. The aim of this study was to analyze the relationship between NIHL and dietary factors using data of the Korea National Health and Nutrition Examination survey (KNHANES). The data were collected from The Fifth KNHANES 2010-2012. The survey was taken by a total of 10,850 participants aged 20-65 years. Air conduction audiometry was measured at 500, 1000, 2000, and 4000 Hz in both ears. Metabolic syndrome, noise exposure, alcohol consumption, smoking, income level, marital status, and nutritional intake were evaluated. The differences between non-HI and HI participants in the noise-exposed group showed statistically significant differences in age, sex, marital and smoking status, alcohol consumption, and fasting glucose and triglyceride levels (p<0.05). In a multiple regression analysis of the noise-exposed group, age showed a significant association with HI (OR: 0.604; 95% CI: 0.538-0.678) after adjusting for confounders. In multivariate analysis for dietary factors affecting HI in noise-exposed groups, retinol (OR: 1.356; 95% CI: 1.068-1.722), niacin (OR: 1.5; 95% CI: 1.022-2.201), and carbohydrates (OR: 0.692; 95% CI: 0.486-0.985) showed a significant association with NIHL. Age was identified as the only factor significantly affecting NIHL. When the dietary factors of the noise-exposed group were analyzed, high intake of niacin and retinol and low intake of carbohydrates appeared to reduce the risk of hearing loss.

Association of smoking status, duration and amount with the risk of head and neck cancer subtypes: a national population-based study.

Smoking is positively associated with multiple cancer types including head and neck cancer (HNC). We sought to confirm the effect of smoking in HNC and subtypes through big data analysis. All data used in this study originated from the Korean National Health Insurance Service database. We analyzed subjects who had undergone health check-ups in 2009 with follow-up until 2018 (n=10,585,852). We collected data on smoking and other variables that could affect the risk of HNC. The overall incidence of HNC was highest in current smokers (HR: 1.822, 95% CI: 1.729-1.920), followed by ex-smokers (HR: 1.242, 95% CI: 1.172-1.317). Laryngeal cancer, hypopharynx cancer, oral cancer, oropharyngeal cancer, and salivary gland cancer showed increasing incidence rates from ex-smokers to current smokers. Smoking duration and amount showed a dose-dependent relationship with the occurrence of HNC. However, the incidence of HNC did not increase significantly when smoking duration was less than 10 years, or when the smoking amount was less than 10 pack-years in ex-smokers. Smoking is associated with the risk of HNC. Smoking cessation before 10 years or 10 pack-years can prevent the development of HNC.

Association of Estimated Glomerular Filtration Rate with Risk of Head and Neck Cancer: A Nationwide Population-Based Study.

In this study, through a cohort study of 10 million people, we investigated the association between estimated glomerular filtration rate (eGFR) and head and neck cancer (HNC) incidence. This is an observational cohort study using data from the national health claims database established by the Korean National Health Insurance Service (NHIS). We selected 9,598,085 participants older than 20 years who had undergone health checkups in 2009. A health checkup involves the history of any diseases, current health status, and results of several physical and blood exams including eGFR. We investigated the presence of HNC diagnosis in their national health insurance data from 2010 to 2018. Of the 9,598,085 participants, 10,732 had been newly diagnosed with HNC in the 9-year follow-up. In the multivariate Cox proportional hazard model, participants with elevated eGFR were associated with a risk of HNC incidence (HR = 1.129; 95% CI = 1.075−1.186 for eGFR = 90−104 mL/min/1.73 m2 and HR = 1.129; 95% CI = 1.076−1.194 for eGFR ≥ 105 mL/min/1.73 m2) compared with those with eGFR 60−89 mL/min/1.73 m2. Among HNC, the incidences of oral cavity, oropharyngeal, hypopharyngeal, and laryngeal cancers were significantly increased in the elevated eGFR group. According to the subgroup analysis, participants with eGFR ≥ 60 mL/min/1.73 m2 were correlated with risk of HNC incidence in middle age, non/mild drinker, low BMI, no diabetes, and no hypertension patients compared with those with eGFR < 60 mL/min/1.73 m2. Elevated eGFR was associated with the risk of some type of HNC, even in individuals with adjusted hypertension and diabetes without chronic diseases. The results of this study have implications for etiological investigations and preventive strategies.

Associations of Body Mass Index and Waist Circumference with the Risk of Head and Neck Cancer: A National Population-Based Study.

Background: We investigated the association between BMI and HNC subtype incidence in a cohort study of ten million people, adjusting for the effect of smoking and drinking. We also investigated the relationship between waist circumference (WC) and HNC subtype. Methods: All data used in this study originated from the Korean National Health Insurance Service database. We analysed subjects who had undergone health check-ups in 2009 and monitored subjects until 2018 (n = 10,585,852). Finally, 9,598,085 subjects were included after exclusions. We collected variables that could affect the risk of HNC. Cox proportional hazards regression analysis was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). Results: The overall incidence of HNC was higher in the low BMI category (BMI < 18.5 according to WHO recommendations for Asian people) (HR: 1.322; 95% CI: 1.195−1.464) compared with the normal BMI category. Among the HNC cases, the incidence rates of laryngeal (HR: 1.3; 95% CI: 1.085−1.558), oral cavity (HR: 1.277; 95% CI: 1.011−1.611), and oropharyngeal (HR: 1.584; 95% CI: 1.25−2.008) cancers were higher in the low BMI category compared with the normal BMI category. No significant association was detected between low BMI and sinus cancer, salivary gland cancer, or nasopharyngeal cancer. The low WC category (<80 cm in men and <75 cm in women) was related to a risk of hypopharyngeal (HR: 1.268; 95% CI: 1.061−1.514) and laryngeal (HR: 1.118; 95% CI: 1.007−1.241) cancers. The HR for occurrence of HNC was high in underweight participants according to smoking status (1.219 for never smoker vs. 1.448 for ever smoker, p for interaction = 0.0015) and drinking status (1.193 for never drinker vs. 1.448 for ever drinker, p for interaction = 0.0044). Conclusions: Low BMI was associated with the risk of some types of HNC. The results of this study could assist etiological investigations and prevention strategies.

Association between γ-Glutamyltransferase and Head and Neck Cancer in Korean Population: A National Population-Based Study.

BACKGROUND: Gamma-glutamyltransferase (GGT) is positively associated with several cancer types. The objective of this study was to investigate the association between GGT and head and neck cancer (HNC) incidence in a cohort of 10 million people, considering effects of smoking and alcohol consumption. METHODS: All data used in this study were obtained from the Korean National Health Insurance Service database. We analyzed subjects who underwent health check-ups in 2009 and monitored them until 2018 (n = 9,597,952). Using proportional hazards models, quartiles of GGT as independent predictors for HNC incidence were evaluated. RESULTS: The overall incidence of HNC increased in the highest quartile [r-GPT ≥ 40 U/L; HR, 1.452; 95% confidence interval (CI), 1.354-1.557]. Among HNC cases, the HR for hypopharyngeal cancer (HR, 2.364; 95% CI, 1.818-3.074) was significantly higher. HRs for HNC (larynx, sino-nasal, oropharynx, oral cavity, and nasopharynx, except salivary glands) were also significant. CONCLUSIONS: Elevated GGT was associated with the risk of some types of HNCs, such as hypopharyngeal, laryngeal, sinonasal, oropharyngeal, oral cavity, and nasopharyngeal cancer. IMPACT: Results of this study have implications for etiologic investigations and preventive strategies.

Close Surgical Margins in Oral and Oropharyngeal Cancer: Do They Impact Prognosis?

Introduction. Mucosal margins exhibit a mean shrinkage of 30−40% after resection of oral and oropharyngeal cancers, and an adequate in situ surgical margin frequently results in a pathological close margin. However, the impact on prognosis remains unclear. We investigated the impact of a pathological close margin on disease-free survival (DFS) and overall survival (OS). Methods. We retrospectively reviewed the clinicopathological data of 418 patients diagnosed with squamous cell carcinomas of the oral cavity or oropharynx who underwent initial surgery (with curative intent) at our institute between 2010 and 2016. Results. Of the total population, the pathological marginal status of 290 (69.4%) patients was reported as clear (>5 mm), 61 (14.6%) as close (>1 mm, ≤5 mm), and 67 (16.0%) as positive (≤1 mm). The 5-year DFSs were 79.3%, 65.1%, and 52% in patients in the negative margin (group 1), close margin (group 2), and positive margin (group 3) groups, respectively. The difference between groups 1 and 2 was not significant (p = 0.213) but the difference between groups 2 and 3 was (p = 0.034). The 5-year OSs were 79.4%, 84%, and 52.3% in groups 1, 2, and 3, respectively. The difference between groups 1 and 2 was not significant (p = 0.824) but the difference between groups 2 and 3 was (p = 0.001). In multivariate analysis, older age, advanced T stage, and a positive margin were independently prognostic of the 5-year DFS and OS. Conclusion. In conclusion, the OS of patients with close margins was no different than that of others when appropriate postoperative adjuvant and/or salvage treatment were/was prescribed. However, we could not determine the impact of close margins on locoregional recurrence given various biases in our study setting. A future prospective study is needed.

Sex Differences in the Prevalence of Head and Neck Cancers: A 10-Year Follow-Up Study of 10 Million Healthy People.

Background: Descriptive epidemiologists have repeatedly reported that males are more susceptible to head and neck cancers. However, most published data are those of cross-sectional studies, and no population-based cohort study has yet been published. The aim of this study was to compare the prevalence of head and neck cancers in healthy males with females. Methods: A retrospective cohort study using the Korean National Health Insurance Service database on 9,598,085 individuals who underwent regular health checkups from 1 January to 31 December 2009. We sought head and neck cancers developed during the 10-year follow-up. Results: A total of 10,732 (incidence rate (IR) per 1000 person-years 0.25) individuals were newly diagnosed with head and neck cancer among the 9,598,085 individuals during the 10-year follow-up. The IR was 0.19 in males (8500 affected) and 0.06 in females (2232 affected). Notably, the male−female ratio increased with age below 70 years but decreased thereafter. The male−female difference was most apparent for laryngeal cancer; the male IR was 11-fold higher in the 40 s and 20-fold higher in the 60 s, followed by hypopharyngeal cancer (6.8- and 24.2-fold). Males smoked more and drank more alcohol than females (p < 0.0001 *, p < 0.0001 *). When never-smokers/-drinkers (only) were compared, males remained at a 2.9-fold higher risk of head and neck cancer than females. The hazard ratios for head and neck cancers in males tended to increase in the lower part of the upper aerodigestive tract: larynx (13.9) > hypopharynx (10.9) > oropharynx (4.4) > nasopharynx (2.9) > sinonasal region (1.8) > oral (1.6). Only the salivary gland cancer incidence did not differ between the sexes; the gland is not in the upper aerodigestive tract. Conclusion: Males are much more susceptible to head and neck cancers than females regardless of whether they drink alcohol or smoke tobacco. Sex differences in the incidence of head and neck cancer are most evident in the 60 s in the lower part of the upper aerodigestive tract, such as the larynx and hypopharynx.

Prophylactic contralateral neck dissection has no advantage in patients with early stage HPV-positive tonsil cancer.

BACKGROUND: Patients with locally advanced HPV-positive tonsil cancer would benefit from prophylactic contralateral neck dissection (pCND). AIMS/OBJECTIVES: The aim of this study was to analyze rates of contralateral lymph node metastases (LNM) and their prognostic effects on locally advanced HPV-positive tonsillar squamous cell carcinoma. MATERIALS AND METHODS: Medical records of 54 patients who underwent upfront primary surgery and pCND were retrospectively reviewed. RESULTS: Six (11.1%) patients had contralateral LNM in 54 locally advanced HPV-positive tonsil cancer. Of these, five patients had contralateral level II LNM and one patient had contralateral level II and III LNM. Contralateral LNM showed significant positive correlations with advanced T stage (p = .017) and the presence of extracapsular spread (p = .007). Contralateral lymph node metastasis had no significant association with five-year disease-specific survival. CONCLUSIONS AND SIGNIFICANCE: This study demonstrated no advantage in performing pCND in early stage HPV-positive tonsil cancer.

Stabilization of Interval Type-2 Fuzzy-Based Reliable Sampled-Data Control Systems.

This article investigates the stabilization problem of the Takagi-Sugeno (T-S) fuzzy-based interval type-2 (IT-2) reliable sampled-data control system. Different from the existing studies, the information for the entire sampling interval with a relation of the augmented state vectors is considered for designing the reliable sampled-data control of IT-2 T-S fuzzy systems. In this regard, we construct the suitable looped Lyapunov-Krasovskii functional (LKF) with the information of the fuzzy membership function that feeds back the time derivative of the membership function to derive sufficient conditions. These sufficient conditions are established in the form of linear matrix inequalities (LMIs), which ensure the global asymptotic stability of T-S fuzzy systems under the designed control technique. Finally, the applicability and superiority of developed reliable sampled-data control techniques were validated by three practical systems.

Retarded Sampled-Data Control Design for Interconnected Power System With DFIG-Based Wind Farm: LMI Approach.

In this article, we investigate the robust stabilization for an interconnected power system with a doubly fed induction generator (DFIG)-based wind farm via retarded sampled-data control (RSDC). Generally, the interconnected power system with DFIG-based wind farm considers a mechanical torque, and load deviation, which is taken into disturbance of the proposed model. The main concern of this article is to stabilize and mitigate the frequency fluctuation, and speed deviation of the DFIG-based wind farm. To do this, a more general sampled-data control strategy, involving the effect of constant time delay is considered and the sampling period is assumed to vary within an interval. In addition, the defined disturbances are attenuated by using the H∞ performance-based RSDC scheme. An appropriate Lyapunov Krasovskii functional (LKF) is constructed to obtain the delay-dependent sufficient conditions in the form of linear matrix inequalities (LMIs) by using the RSDC strategy. The obtained conditions ensure the proposed closed-loop system is asymptotically stable under the designed controller. Finally, simulation results and comparative results are given to illustrate the effectiveness of the designed control scheme.