Stabilizing regions of dominant pole placement for second order lead processes with time delay using filtered PID controllers.

In order to handle second order lead processes with time delay, this paper provides a unique dominant pole placement based filtered PID controller design approach. This method does not require any finite term approximation like Pade to obtain the quasi-polynomial characteristic polynomial, arising due to the presence of the time delay term. The continuous time second order plus time delay systems with zero (SOPTDZ) are discretized using a pole-zero matching method with specified sampling time, where the transcendental exponential delay terms are converted into a finite number of poles. The pole-zero matching discretization approach with a predetermined sampling period is also used to discretize the continuous time filtered PID controller. As a result, it is not necessary to use any approximate discretization technique, such as Euler or Tustin, to derive the corresponding discrete time PID controller from its continuous time counterpart. The analytical expressions for discrete time dominant pole placement based filtered PID controllers are obtained using the coefficient matching approach, while two distinct kinds of non-dominant poles, namely all real and all complex conjugate, have been taken into consideration. The stabilizable region in the controller and design parameter space for the chosen class of linear second order time delay systems with lead is numerically approximated using the particle swarm optimization (PSO) based random search technique. The efficacy of the proposed method has been validated on a class of SOPTDZ systems including stable, integrating, unstable processes with minimum as well as non-minimum phase zeros.

Surya Namaskar: As an Alternative for Aerobic Fitness.

Context: "Surya Namaskar" (SN) may be used as a need-based short-duration aerobic activity in a confined space to establish as a substitute of an equivalent routine physical training in challenging stressful conditions. Materials and Methods: Noninvasive oxygen-kinetics metabolic responses between SN and endurance work on bicycle ergometry (BE) were compared across different phases of maximal oxygen uptake percentage (%VO2 max). SN, comprising three complete rounds per min (36 beats/min of a metronome; SN consists of 12 poses per round), was performed rhythmically and continuously for 5 min to simulate an incremental BE test (25 watts/2 min at 60 rpm). Results: SN results in a significant (P < 0.05) greater increase of arteriovenous oxygen difference at 71%-80% VO2 max while keeping a low respiratory exchange ratio (P < 0.01 and 0.001) at 41%-80% VO2 max exercising state. Conclusions: SN could be an ideal form of aerobic exercise instead of BE.

Autonomous Collision Avoidance Using MPC with LQR-Based Weight Transformation.

Model predictive control (MPC) is a multi-objective control technique that can handle system constraints. However, the performance of an MPC controller highly relies on a proper prioritization weight for each objective, which highlights the need for a precise weight tuning technique. In this paper, we propose an analytical tuning technique by matching the MPC controller performance with the performance of a linear quadratic regulator (LQR) controller. The proposed methodology derives the transformation of a LQR weighting matrix with a fixed weighting factor using a discrete algebraic Riccati equation (DARE) and designs an MPC controller using the idea of a discrete time linear quadratic tracking problem (LQT) in the presence of constraints. The proposed methodology ensures optimal performance between unconstrained MPC and LQR controllers and provides a sub-optimal solution while the constraints are active during transient operations. The resulting MPC behaves as the discrete time LQR by selecting an appropriate weighting matrix in the MPC control problem and ensures the asymptotic stability of the system. In this paper, the effectiveness of the proposed technique is investigated in the application of a novel vehicle collision avoidance system that is designed in the form of linear inequality constraints within MPC. The simulation results confirm the potency of the proposed MPC control technique in performing a safe, feasible and collision-free path while respecting the inputs, states and collision avoidance constraints.

Improvement in resilience and stress-related blood markers following ten months yoga practice in Antarctica.

BACKGROUND: Wintering is associated with distress to humans who work in the isolated and confined environment of Antarctica and yoga has been proved helpful for coping with stress. Therefore, a study was conducted on 14 winter expedition members of Indian Scientific Antarctic Expedition (2016) to find out the effects of yoga on stress-related markers. METHODS: Participants were divided into yoga, and control (non-yoga) groups. The yoga group practiced yoga for 10 months (from January to October 2016) daily in the morning for an hour. The Resilience test questionnaire was administrated at baseline and endpoint of the study. Blood samples were collected during the study at different intervals for the estimation of 8-hydroxydeoxyguanosine (8-OHdG), brain-derived neurotrophic factor (BDNF), serotonin and cortisol using ELISA. RESULTS: A trend of improvement was observed in the resilience test score in the yoga group. From January to October, 8-OHdG serum values in the yoga group declined by 55.9% from 1010.0 ± 67.8 pg/mL to 445.6 ± 60.5 pg/mL (Mean ± SD); in the control group, the decline was 49.9% from 1060.4 ± 54.6 pg/mL to 531.1 ± 81.8 pg/mL. In serotonin serum levels in the yoga group, there was a 3.1% increase from 6.4 ± 1.6 ng/mL to 6.6 ± 0.4 ng/mL while no increase was noticed in the control group. Cortisol values in the yoga group decreased by 19.9% from 321.0 ± 189.6 ng/mL to 257.1 ± 133.8 ng/mL; in the control group it increased by 2.8% from 241.2 ± 51.8 ng/mL to 247.8 ± 90.9 ng/mL. CONCLUSIONS: It could be concluded from the present study that following 10 months yoga practice may be useful for better resilience and management of stress-related blood markers for the polar sojourners.

Stability and Performance Analysis of Networked Control Systems: A Lifted Sample-Time Approach with L2 Induced Norm.

The lifted sample-time approach has been extensively applied to analyze the behavior of a Networked Control System (NCS) under instances of packet-drop and/or variable communication latency (jitter) of varying durations. This paper combines the simplicity of the lifted sample-time approach in modeling an NCS under arbitrary but bounded instances of packet-drop and/or jitter with the proven L2induced norm based approach of controller design to realize an NCS which is capable of preserving the designed value of the norm under assumed conditions of packet-drop and/or jitter and hence a satisfactory time response under these conditions. The design methodology presented in this paper assumes a state feedback controller and uses a simple criterion based on a Linear Matrix Inequality (LMI). The methodology is validated using credible offline and real-time simulations.

Age related differences of selected Hatha yoga practices on anthropometric characteristics, muscular strength and flexibility of healthy individuals.

BACKGROUND: Physiological benefits of yoga on volunteers of a particular age group are available. However, reports on efficacy of a specific yoga package on the populace of different age groups from similar occupational background is still very limited. Therefore, the present study was conducted to appraise the effect of a specific Hatha yoga package on anthropometric characteristics, flexibility and muscular strength of healthy individuals of different age groups from similar occupational trade. MATERIALS AND METHODS: A total of 71 participants (Group All) from Indian Air Force ground personnel volunteered and age wise divided into 3 groups - (i) Group I (Gr. - I) (n1 = 27, 20-29 years), (ii) Group II (Gr. - II) (n2 = 21, 30-39 years) and (iii) Group III (Gr. - III) (n3 = 23, 40-49 years). All the participants undergone selected Hatha yoga training for 1 h daily for a period of 12 weeks. Parameters were recorded before and after the training. Pre and post training differences were assessed by Student's t-test. RESULTS: Body weight (All, Gr. - II and Gr. - III [all P < 0.05]), body mass index (Gr. - II and Gr. - III [both P < 0.01]) and fat% (Gr. - II and III [both P < 0.05]) were decreased significantly. Neck circumference was increased significantly in Gr. - I (P < 0.05) but decreased significantly in Gr. - III (P < 0.05). Chest circumference (All (P < 0.001), in Gr. - I and II [both P < 0.05]), grip strength (All [left: P < 0.01 and right: P < 0.05], in Gr. - I [left: P < 0.05 and right: P < 0.01], in Gr. - II [right: P < 0.05] and in Gr. - III [left: P < 0.05 and right: P < 0.01]), back leg strength (group wise P < 0.001, P < 0.05, P < 0.01 and P < 0.05 respectively) and flexibility (all P < 0.001) were increased significantly. SUMMARY AND CONCLUSION: Hatha yoga can improve anthropometric characteristics, muscular strength and flexibility among volunteers of different age group and can also be helpful in preventing and attenuating age related deterioration of these parameters.

Effects of Yogic Practice on Metabolism and Antioxidant-Redox Status of Physically Active Males.

BACKGROUND: This study was conducted to evaluate the effects of yogic practice on resting metabolism and redox status. METHODS: The study was conducted on 64 physically trained male volunteers selected randomly at the Air Force Academy. The yoga group (n = 34) practiced yogasana, pranayama, and meditation for 3 months (February-May 2011) and the control group (n = 30) performed physical training. Antioxidant variables in blood samples along with physiological parameters were estimated before and after 3 months. RESULTS: No significant difference was noted between baseline data of the control group and yoga group. Reduced glutathione, vitamin C, and vitamin E; the ratio of reduced to oxidized glutathione; and total antioxidant status were increased significantly following yogic practice. Activities of superoxide dismutase, glutathione S-transferase, and glutathione reductase were significantly increased, whereas activity of glutathione peroxidase was significantly decreased following yogic practice. Oxidized glutathione decreased significantly following yogic practice. A nonsignificant decrease of hydroperoxides, protein carbonyl, malondialdehyde, and blood sugar was noted in the yoga group. Carbon dioxide elimination and peripheral oxygen saturation increased significantly following yogic practice. No significant changes were observed in the control group following 3 months of physical training. CONCLUSIONS: Regular yogic practice can improve resting metabolism and redox status of the practitioner.

Utility of imprint cytology for early presumptive diagnosis in clinically suspicious cervical cancer.

OBJECTIVE: To determine the utility of imprint cytology (IC) in providing an early presumptive diagnosis of clinically suspected cervical carcinoma. STUDY DESIGN: A total of 219 clinically suspicious cervical cancer cases underwent Pap test, punch biopsy and IC at the same sitting. Correlations were performed between these diagnostic modalities to determine the sensitivity and specificity of IC in diagnosis of cervical cancer. RESULTS: The overall accuracy of IC in detecting cervical cancers was 96.2%. About 78% of squamous cell carcinomas (SCC), 60% of adenocarcinomas and 100% of small cell carcinoma could be accurately typed on imprints. Twelve malignant lesions were diagnosed on IC among 26 unsatisfactory biopsies. Although there was no false positive result, 3.5% false negative diagnoses were given on IC. The sensitivity and specificity of imprint smear cytology to detect malignancy was 96.2% and 100%. Agreement between imprint cytology and Pap smear diagnosis of malignancy was 95.3%. kappa Statistics revealed excellent agreement between imprints and biopsies and between imprints and Pap smears in diagnosis of malignant lesions. CONCLUSION: IC can be used as an adjunctive technique for an early and reliable preliminary presumptive diagnosis of cancer of the uterine cervix.

Spectrum of epithelial cell abnormalities of uterine cervix in a cervical cancer screening programme: implications for resource limited settings.

OBJECTIVE: (1) To compute the frequencies and peak age incidences of epithelial cell abnormalities (ECA) of uterine cervix in a cytology-based screening programme and (2) to analyze the comparative frequencies of squamous intraepithelial lesions (SIL) and malignancies in age groups <40 and > or =40 years, in order to assess the implications for screening protocol in resource limited settings. STUDY DESIGN: Pap smears form 29,475 women were cytologically screened over a 4-year period as a part of hospital-based screening programme. The frequencies, peak age incidences and mean age of various ECA detected were computed. The data was further stratified in to age groups <40 (Gp 1) and > or =40 (Gp 2) and comparative profile of the lesions was analyzed. RESULTS: On cytologic screening of the smears 5.6% ECA were detected. Atypical squamous cells-undetermined significance (ASC-US) and low grade SILs (LSIL) were diagnosed more frequently in Gp 1 (p<0.001) while atypical glandular cells (AGC) and malignancies were more significantly more frequent in Gp 2 (p<0.001). The frequency of HSIL was similar in the two groups. The SILs predominated in the fourth decade while the malignant lesions were most frequent in age >50 years. The mean age for LSIL and HSIL was 34.7 and 37.7 years, respectively, while for malignancy it was 51.8 years thus corroborating the hypothesis that a prolonged latent phase exists between the precursor lesions and the onset of invasive cancer. CONCLUSIONS: Since the goal of any screening programme should be to pick up majority of the precursor lesions and not frank cancers, it is desirable to initiate screening before 40 years of age. The WHO recommendation of once in a life time screening between 35 and 40 years of age seems appropriate for resource limited settings like ours.

Sensitivity of the Pap test in detecting high grade lesions: what should be the acceptable cytologic threshold for colposcopic referral?

OBJECTIVE: To devise an optimal cytology threshold for colposcopy referral in resource-limited settings. STUDY DESIGN: Four hundred seventy-two symptomatic women 20-60 years old were screened by both cytology and colposcopy. Onsite biopsy was taken if lesions grade 1 or above were detected on colposcopy. Women found to have cervical intraepithelial neoplasia (CIN) 2 and above lesions on histopathology were stratified according to their cytologic diagnosis (atypical squamous cells of undetermined significance [ASCUS]+ threshold, low grade squamous intraepithelial lesion [LSIL]+ threshold, and high grade squamous intraepithelial lesion [HSIL]+ threshold). The comparative sensitivity, specificity and predictive values in each group were calculated, taking biopsy as the gold standard. RESULTS: The sensitivity of LSIL + cytology to detect CIN 2+ lesions was 91.5% (referral load, 30.7%). While the sensitivity of ASCUS+ cytology threshold was almost the same (92.3%), the referral load was much higher (42.2%). With HSIL+ cytology threshold, though the referral load was reduced substantially (21.9%), the sensitivity also decreased, to 81.5%. CONCLUSION: The results indicate that in order to achieve high sensitivity, the LSIL cytology threshold appears to be optimum for colposcopic referrals.