Combining synergetic control and super twisting algorithm to reduce the active power undulations of doubly fed induction generator for dual-rotor wind turbine system

Aim. This work presents the amelioration of direct power control using synergetic-super twisting algorithms for asynchronous generators integrated into dual-rotor wind turbine systems. Method. The main role of the direct power control is to control the active and reactive powers and reduce the harmonic distortion of stator current of asynchronous generator for variable speed dual-rotor wind turbine systems. The traditional strategy is more attractive due to its high efficiency and simple algorithm. Super twisting algorithms are a non-linear command strategy; characterized by robustness against the parameters change or disturbances, it gives a good power quality under different conditions such as changing generator parameters. Novelty. Synergetic-super twisting algorithms are designed. Synergetic-super twisting algorithms construction is based on synergetic command and super twisting algorithms in order to obtain a robust control strategy and a fast system with acceptable precision. We use in our study a 1.5 MW asynchronous generator integrated to dual-rotor wind turbine system in order to regulate the active and reactive powers. Results. As shown in the results figures using synergetic-super twisting algorithms the ameliorate performances especially minimizes the torque, active and reactive power undulations, and reduces harmonic distortion of stator current (THD = 0.19 %) compared to traditional strategy.Мета. Робота представляє вдосконалення безпосереднього регулювання потужності за допомогою синергетичих алгоритмів супер-скручування для асинхронних генераторів, інтегрованих у системи вітряних генераторів з подвійним ротором. Метод. Основна роль безпосереднього регулювання потужності полягає у керуванні активною та реактивною потужностями та зменшенні гармонічних спотворень струму статора асинхронного генератора для вітряних генераторів з подвійним ротором зі змінною швидкістю обертання. Традиційна стратегія є більш привабливою завдяки її високій ефективності та простому алгоритму. Алгоритми супер-скручування – це нелінійна командна стратегія; характеризується стійкістю до зміни параметрів або порушень, це забезпечує хорошу якість енергії в різних умовах, таких як зміна параметрів генератора. Новизна. Розроблені синергетичні алгоритми супер-скручування. Побудова алгоритмів синергетичного супер-скручування базується на алгоритмах синергетичних команд та супер-скручування, для того щоб отримати надійну стратегію керування та швидку систему з прийнятною точністю. У нашому дослідженні ми використовуємо асинхронний генератор потужністю 1,5 МВт, інтегрований в систему вітряних турбін з подвійним ротором для регулювання активної та реактивної потужностей. Результати. Як показано на рисунках з результатами, із використанням алгоритмів синергетичного супер-скручування, покращені характеристики особливо мінімізують крутний момент, коливання активної та реактивної потужності та зменшують гармонічні спотворення струму статора (THD = 0,19%) порівняно з традиційною стратегією

INCIDENCE, DEPENDENT AND INDEPENDENT RISK FACTORS ASSOCIATED TO NOSOCOMIAL INFECTIONS AND TO THE MORTALITY AT THE INTENSIVE CARE UNIT OF THE TIMONE UNIVERSITY HOSPITAL

ICU (intensive care unit) patients are highly concerned by a risk of nosocomial infection. This is due to the seriousness of the treated pathologies, and more and more to invasive medical procedures, in short, a day-to-day hazard of health care. The aim of this study is to assess the risk factors of nosocomial infections and mortality in ICU, to estimate the proportion of predominant organisms, and to record the disease resistance profiles. This study was based on a total of 250 patients who were at least 16-year old and who had spent at least 72 hours in ICU.Among the 46 patients who developed at least one nosocomial episode, 42 (91.3%) had been hospitalized for a minimum of 6 days (this being the average stay for patients without any nosocomial episode). The mortality rate was 23.9%. The most frequently reported infection was pneumonia contracted through mechanical ventilation, with a percentage of 47.8%, followed by lung infections with a rate of 23.9%. Bacteremia and urinary infections represented 17.4% and 10.4%, respectively. 41.3 % of isolated bacteria were Gram-positive. All of the 46 patients received antibiotics during their stay at the intensive care unit. The results of logistic regression and multivariate analysis (P < 0.05) conclude that the nosocomial event was significantly related to the length of stay OR: 1.073 [1.009 – 1.149], neurological disease OR: 3.21 [1.28 – 8.33] and the presence of a CVC (central venous catheter) OR: 15.3 [1.68 – 507.4]. Additionally, age OR: 1.02 [1.002 – 1.054], cancer OR: 3.07 [1.32– 7.21] and SOFA score >4 OR: 7.58 [2.63 - 29.03] are related to the death risk.In light of this study, we concluded that CVC and neurological disease are high-risk factors for nosocomial infection whereas SOFA score >4 and cancer are identified as high risk factors for mortality

RISK FACTORS’ IDENTIFICATION ACCORDING TO THE DEVELOPMENT OF HEALTHCARE ASSOCIATED INFECTIONS AND MORTALITY BY USING COMPETING MODELS AT TIMONE UNIVERSITY HOSPITAL’S ICU

Whatever their specialty (surgical, medical or both), intensive care units have to take care of patients due to life-threatening conditions as the result of one or even several organ failures. They register the highest mortality rates (Sheng WH, 2005), and the highest numbers of nosocomial infections (Mathieu LM, 2001). There have been numerous studies intended to evaluate the risk factors and the consequences of these infections in ICU (Intensive Care Unit) patients. However the analyses in most of these studies disregard the fact that there are additional competing events such as discharge or death. The study is retrospective. It is based on a total of 250 patients of at least 16 years old and having spent at least 72 hours in ICU in the Timone University Hospital. Several risk factors were studied in two distinct competitive risk models. In the first model, we investigated the nosocomial infections risk factors with such a competing risk model as discharge (patients dead or living). The mortality risk factors were studied in the second model in which the patient being discharged faces the mortality competing risk. 46 patients developed at least one nosocomial episode, and 65 died. The nosocomial infection objectified risk factors are: CVC (causespecific hazard ratio = 9.08; 95% CI 1.10 to 75.20), chronic renal failure (8.99; 95% CI 1.92 to 42.12) and tracheotomy (2.69; 95% CI 1.45 to 5.01). Cancer (2.69; 95% CI 1.48 to 4.89), transplant (7.30; 95% CI 1.83 to 29.19) and the SOFA score (1.36; 95% CI 1.23 to 1.51) are the target factors for mortality risk. Of all the documented scores in the present study the SOFA is the score with the highest predictive capacity as far as death risk is concerned. On the other hand, even if the nosocomial infection alters the event discharge, its impact on mortality is not completely establishe

Indirect active and reactive powers control of doubly fed induction generator fed by three-level adaptive-network-based fuzzy inference system – pulse width modulation converter with a robust method based on super twisting algorithms

Aim. This paper presents the minimization of reactive and active power ripples of doubly fed induction generators using super twisting algorithms and pulse width modulation based on neuro-fuzzy algorithms. Method. The main role of the indirect active and reactive power control is to regulate and control the reactive and active powers of doubly fed induction generators for variable speed dual-rotor wind power systems. The indirect field-oriented control is a classical control scheme and simple structure. Pulse width modulation based on an adaptive-network-based fuzzy inference system is a new modulation technique; characterized by a simple algorithm, which gives a good harmonic distortion compared to other techniques. Novelty. adaptive-network-based fuzzy inference system-pulse width modulation is proposed. Proposed modulation technique construction is based on traditional pulse width modulation and adaptive-network-based fuzzy inference system to obtain a robust modulation technique and reduces the harmonic distortion of stator current. We use in our study a 1.5 MW doubly-fed induction generator integrated into a dual-rotor wind power system to reduce the torque, current, active power, and reactive power ripples. Results. As shown in the results figures using adaptive-network-based fuzzy inference system-pulse width modulation technique ameliorate effectiveness especially reduces the reactive power, torque, stator current, active power ripples, and minimizes harmonic distortion of current (0.08 %) compared to classical control.Мета У статті представлено мінімізацію пульсацій реактивної та активної потужності асинхронних генераторів подвійного живлення з використанням алгоритмів суперскрутки та широтно-імпульсної модуляції на основі нейро-нечітких алгоритмів. Метод. Основна роль непрямого управління активною та реактивною потужністю полягає у керуванні та регулюванні реактивної та активної потужностей асинхронних генераторів з подвійним живленням для вітроенергетичних систем з подвійним ротором змінної швидкості. Непряме керування, орієнтоване на поле, - це класична схема керування та проста структура. Широтно-імпульсна модуляція, заснована на системі нечітких висновків на основі адаптивної мережі, є новим методом модуляції; характеризується простим алгоритмом, який дає гарні гармонічні спотворення порівняно з іншими методами. Новизна. Пропонується адаптивна мережа на основі нечіткого висновку із широтно-імпульсною модуляцією. Запропонована побудова методу модуляції базується на традиційній широтно-імпульсній модуляції та системі нечітких висновків на основі адаптивних мереж для отримання надійного методу модуляції та зменшення гармонічних спотворень струму статора. У нашому дослідженні ми використовуємо асинхронний генератор з подвійним живленням потужністю 1,5 МВт, інтегрований у вітроенергетичну систему з подвійним ротором, щоб зменшити пульсації крутного моменту, струму, активної потужності та реактивної потужності. Результати. Як показано на рисунках з результатами, використання методу широтно-імпульсної модуляції на основі нечітких висновків системи адаптивних мереж покращує ефективність, особливо зменшує реактивну потужність, крутний момент, струм статора, пульсації активної потужності, та мінімізує гармонійне спотворення струму (0,08 %) порівняно з класичним керуванням

STRONG REPRESENTATION OF THE QUANTILE FUNCTION FOR LEFT TRUNCATED AND DEPENDENT DATA

International audienceLet (X i) i≥1 be a sequence of strong-mixing random variables with common unknown absolutely continuous distribution function F subject to random left truncation. Let F −1 (p) denote the pth (p ∈]0, 1[) quantile function of the marginal distribution function of the X i 's which is estimated by the sample quantile F −1 n (p). In this paper, we derive the strong consistency and a strong representation for F −1 n (p), the quantile function of the Lynden-Bell estimator of F for strong-mixing processes

Likelihood Ratio Testing for Admixture Models with Application to Genetic Linkage Analysis

We consider likelihood ratio tests (LRT) and their modifications for homogeneity in admixture models. The admixture model is a special case of two component mixture model, where one component is indexed by an unknown parameter while the parameter value for the other component is known. It has been widely used in genetic linkage analysis under heterogeneity, in which the kernel distribution is binomial. For such models, it is long recognized that testing for homogeneity is nonstandard and the LRT statistic does not converge to a conventional 2 distribution. In this paper, we investigate the asymptotic behavior of the LRT for general admixture models and show that its limiting distribution is equivalent to the supremum of a squared Gaussian process. We also provide insights on the connection and comparison between LRT and alternative approaches in the literature, mostly modifications of LRT and score tests, including the modified or penalized LRT (Fu et al., 2006). The LRT is an omnibus test that is powerful against general alternative hypothesis. In contrast, alternative approaches may be slightly more powerful against certain type of alternatives, but much less powerful for other types. Our results are illustrated by simulation studies and an application to a genetic linkage study of schizophrenia

User-centered visual analysis using a hybrid reasoning architecture for intensive care units

One problem pertaining to Intensive Care Unit information systems is that, in some cases, a very dense display of data can result. To ensure the overview and readability of the increasing volumes of data, some special features are required (e.g., data prioritization, clustering, and selection mechanisms) with the application of analytical methods (e.g., temporal data abstraction, principal component analysis, and detection of events). This paper addresses the problem of improving the integration of the visual and analytical methods applied to medical monitoring systems. We present a knowledge- and machine learning-based approach to support the knowledge discovery process with appropriate analytical and visual methods. Its potential benefit to the development of user interfaces for intelligent monitors that can assist with the detection and explanation of new, potentially threatening medical events. The proposed hybrid reasoning architecture provides an interactive graphical user interface to adjust the parameters of the analytical methods based on the users' task at hand. The action sequences performed on the graphical user interface by the user are consolidated in a dynamic knowledge base with specific hybrid reasoning that integrates symbolic and connectionist approaches. These sequences of expert knowledge acquisition can be very efficient for making easier knowledge emergence during a similar experience and positively impact the monitoring of critical situations. The provided graphical user interface incorporating a user-centered visual analysis is exploited to facilitate the natural and effective representation of clinical information for patient care

Does biological maturity actually confound gender-related differences in physical activity in preadolescence?

Aim To examine: (i) if maturity-related gender differences in moderate-to-vigorous physical activity (MVPA) depend on how maturity status is defined and measured; and (ii) the influence of maturity level on compliance with PA recommendations. Methods The study involved 253 children (139 boys) aged 9.9 ± 0.9 years, with mean stature and weight of 1.39 ± 0.08 m and 35.8 ± 8.8 kg respectively. Their PA was evaluated using an Actigraph accelerometer (Model 7164). Maturity was assessed using the estimated age at peak height velocity (APHV) and a standardized APHV by gender (i.e. centred APHV). Results Boys engaged in significantly more MVPA than girls (P < 0.0001). There was a significant correlation between the centred APHV and MVPA in boys (r = 0.20; P = 0.016), but not in girls (r = 0.13; P = 0.155). An ancova controlling for the estimated APHV showed no significant interactions between gender and APHV, and the main effect of gender on MVPA was negated. Conversely, there was a significant main effect of APHV on MVPA (F 1,249 = 6.12; P = 0.014; η p 2 = 0.024). Only 9.1% of children met the PA recommendations, including 14.4% of boys and 2.6% of girls (P < 0.01). This observation also applies in both pre-APHV (12.7% of boys vs. 2.4% of girls, P < 0.001) and post-APHV children (23.8% of boys vs. 3.4% of girls, P < 0.0001). No differences in PA guidelines were observed between pre-APHV and post-APHV children. Conclusions Among prepubescent children, the influence of biological maturity on gender differences in PA may be a function of how maturity status is determined. The most physically active prepubescent children were those who were on time according to APHV

Analysis of out-of-hospital cardiac arrest and ozone pollution: A qualitative study

Background: Air pollution is increasingly associated with cardiovascular events. As for ozone (O3) pollution, results are inconsistent though O3 levels are associated with hospital admissions, global mortality, and respiratory, and cardiovascular mortality. Methods: In this time-stratified case-crossover study, the associations between short-term exposure to O3 (on an hourly and daily scale) and out-of-hospital cardiac arrests (OHCA) were investigated. Specific subgroups were explored by sex, age, diabetes status, for OHCA during non-holiday periods. Data were collected in the Nord-Pas-de-Calais region, France, in 2015. Data were statistically analyzed using conditional logistic regression (CLR). Results: The study included 1039 cases of OHCA. Significant negative associations were found between OHCA and O3 levels measured in 3 or 4 days before the arrest for all the people, and 1, 2 or 3 days before the arrest for men. As for OHCA during non-holiday periods, there was no significant negative associations but a positive association was revealed for women between OHCA and O3 levels measured in 5 days before the arrest (OR=1.53, P = 0.008). Conclusion: According to the results, OHCA should be investigated during non-holiday periods to control potential confounders that would lead to negative associations. Women might be a susceptible subgroup to O3 pollution. Keywords: Heart arrest, Ozone, Air pollution, Epidemiology, Environmental healt