Применение кластерного анализа с элементами нечеткой логики для оценки окружающей обстановки группы робототехнических средств

Возникновение чрезвычайных ситуаций, которые угрожают жизни и здоровью людей, резко повышает требования к полноте и точности представления информации о текущей ситуации. Современные робототехнические средства оснащены датчиками, работающими на различных физических принципах. Это приводит к росту входной информации, поступающей в управляющую систему. С учетом ограниченной производительности бортовой вычислительной системы, а также высокой априорной неопределенности наземной обстановки робототехнические средства не могут быть эффективно использованы без объединения получаемой информации от группы робототехнических средств и создания единой картины наземной обстановки. Решить задачу отождествления вектор-признаков, относящихся к одному объекту, а также оценить эффективность полученных решений можно по известным формулам теории проверки статистических гипотез и теории вероятностей только при нормальном законе распределения с известными математическим ожиданием вектор-признака и корреляционной матрицей. Однако перечисленные условия на практике, как правило, не выполняются. Предложен новый метод решения задачи отождествления вектор-признаков, не опирающийся на статистический подход, и, следовательно, не требующий знание вида закона распределения и значений его параметров. Предлагаемый метод основан на идее сочетания кластерного анализа и нечеткой логики и отличается сравнительной простой по отношению к базовым методам многомерной непараметрической статистики. Обсуждаются математические аспекты метода нечеткой кластеризации и возможное упрощение алгоритма нечеткого отождествления при временных ограничениях. Установлено, что применение нечеткой кластеризации объектов в сложной наземной обстановке позволяет уменьшить количество ложных распознаваний объектов по сравнению с существующим статистическим подходом, ориентированным на использование нормального закона распределения. Показано преимущество предлагаемого метода отождествления вектор-признаков объектов, даны сравнительные значения по количеству ложных распознаваний. Даны рекомендации построения правил нечеткого вывода при создании базы знаний экспертной системы

Bi2Se3 interlayer treatments affecting the Y3Fe5O12 (YIG) platinum spin Seebeck effect

In this work, we present a method to enhance the longitudinal spin Seebeck effect at platinum/yttrium iron garnet (Pt/YIG) interfaces. The introduction of a partial interlayer of bismuth selenide (Bi2Se3, 2.5% surface coverage) interfaces significantly increases (by ∼380%–690%) the spin Seebeck coefficient over equivalent Pt/YIG control devices. Optimal devices are prepared by transferring Bi2Se3 nanoribbons, prepared under anaerobic conditions, onto the YIG (111) chips followed by rapid over-coating with Pt. The deposited Pt/Bi2Se3 nanoribbon/YIG assembly is characterized by scanning electron microscope. The expected elemental compositions of Bi2Se3 and YIG are confirmed by energy dispersive x-ray analysis. A spin Seebeck coefficient of 0.34–0.62 μV/K for Pt/Bi2Se3/YIG is attained for our devices, compared to just 0.09 μV/K for Pt/YIG controls at a 12 K thermal gradient and a magnetic field swept from −50 to +50 mT. Superconducting quantum interference device magnetometer studies indicate that the magnetic moment of Pt/Bi2Se3/YIG treated chips is increased by ∼4% vs control Pt/YIG chips (i.e., a significant increase vs the ±0.06% chip mass reproducibility). Increased surface magnetization is also detected in magnetic force microscope studies of Pt/Bi2Se3/YIG, suggesting that the enhancement of spin injection is associated with the presence of Bi2Se3 nanoribbons

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Sex difference and intra-operative tidal volume: Insights from the LAS VEGAS study

BACKGROUND: One key element of lung-protective ventilation is the use of a low tidal volume (VT). A sex difference in use of low tidal volume ventilation (LTVV) has been described in critically ill ICU patients.OBJECTIVES: The aim of this study was to determine whether a sex difference in use of LTVV also exists in operating room patients, and if present what factors drive this difference.DESIGN, PATIENTS AND SETTING: This is a posthoc analysis of LAS VEGAS, a 1-week worldwide observational study in adults requiring intra-operative ventilation during general anaesthesia for surgery in 146 hospitals in 29 countries.MAIN OUTCOME MEASURES: Women and men were compared with respect to use of LTVV, defined as VT of 8 ml kg-1 or less predicted bodyweight (PBW). A VT was deemed 'default' if the set VT was a round number. A mediation analysis assessed which factors may explain the sex difference in use of LTVV during intra-operative ventilation.RESULTS: This analysis includes 9864 patients, of whom 5425 (55%) were women. A default VT was often set, both in women and men; mode VT was 500 ml. Median [IQR] VT was higher in women than in men (8.6 [7.7 to 9.6] vs. 7.6 [6.8 to 8.4] ml kg-1 PBW, P < 0.001). Compared with men, women were twice as likely not to receive LTVV [68.8 vs. 36.0%; relative risk ratio 2.1 (95% CI 1.9 to 2.1), P < 0.001]. In the mediation analysis, patients' height and actual body weight (ABW) explained 81 and 18% of the sex difference in use of LTVV, respectively; it was not explained by the use of a default VT.CONCLUSION: In this worldwide cohort of patients receiving intra-operative ventilation during general anaesthesia for surgery, women received a higher VT than men during intra-operative ventilation. The risk for a female not to receive LTVV during surgery was double that of males. Height and ABW were the two mediators of the sex difference in use of LTVV.TRIAL REGISTRATION: The study was registered at Clinicaltrials.gov, NCT01601223