A Sliding Mode Observer design for the Average State Estimation in Large-Scale Systems

In this letter the average state estimation problem on a large-scale system with only few gateway nodes available for measurements is solved as the design problem of a reduced-order sliding mode observer subjected to unmatched perturbations. Necessary and sufficient conditions to guarantee the exact estimation are derived. Still, even in the case such conditions are not fulfilled, the boundedness of the estimation error is proved. Finally, a criteria to minimize such bound, and a gain adaptation law to trade-off that bound and its convergence rate are provided. Neither the observer complexity nor the estimation error depend explicitly on the size of the system, thus making the approach scalable and computationally tractable. Simulations supporting the effectiveness of the proposed strategy and a comparison with other existing strategies are also provided

A device to characterize optical fibres

ATLAS is a general purpose experiment approved for the LHC collider at CERN. An important component of the detector is the central hadronic calorimeter; for its construction more than 600,000 Wave Length Shifting (WLS) fibres (corresponding to a total length of 1,120 Km) have been used. We have built and put into operation a dedicated instrument for the measurement of light yield and attenuation length over groups of 20 fibres at a time. The overall accuracy achieved in the measurement of light yield (attenuation length) is 1.5% (3%). We also report the results obtained using this method in the quality control of a large sample of fibres.Comment: 17 pages 20 figeres submitted to NIM journa

Popularity prediction of instagram posts

Predicting the popularity of posts on social networks has taken on significant importance in recent years, and several social media management tools now offer solutions to improve and optimize the quality of published content and to enhance the attractiveness of companies and organizations. Scientific research has recently moved in this direction, with the aim of exploiting advanced techniques such as machine learning, deep learning, natural language processing, etc., to support such tools. In light of the above, in this work we aim to address the challenge of predicting the popularity of a future post on Instagram, by defining the problem as a classification task and by proposing an original approach based on Gradient Boosting and feature engineering, which led us to promising experimental results. The proposed approach exploits big data technologies for scalability and efficiency, and it is general enough to be applied to other social media as well

Variabilità dell'olio essenziale di <i>Helichrysum italicum</i> (Roth) G. Don

Per lo studio dell'olio essenziale di Helichrysum italicum, sono state prese in considerazione varie stazioni di E. italicum (Roth) G. Don subsp. microphyllum (Willd.) Nyman vegetante allo stato spontaneo sia nel Nord che nel Sud della Sardegna. Le analisi sono state condotte via Gas-massa e ci hanno permesso di identificare 69 costituenti per un totale compreso tra il 92.9% ed il 99.9% dei costituenti totali

The transition from hunting–gathering to agriculture in Nubia: dental evidence for and against selection, population continuity and discontinuity

Some researchers posit population continuity between Late Palaeolithic hunter–gatherers of the late Pleistocene and Holocene agriculturalists from Lower (northern) Nubia, in northeast Africa. Substantial craniodental differences in these time-successive groups are suggested to result from in situ evolution. Specifically, these populations are considered a model example for subsistence-related selection worldwide in the transition to agriculture. Others question continuity, with findings indicating that the largely homogeneous Holocene populations differ significantly from late Pleistocene Lower Nubians. If the latter are representative of the local populace, post-Pleistocene discontinuity is implied. So who was ancestral to the Holocene agriculturalists? Dental morphological analyses of 18 samples (1075 individuals), including one dated to the 12th millennium BCE from Al Khiday, near the Upper Nubian border, may provide an answer. It is the first Late Palaeolithic sample (n = 55) recovered within the region in approximately 50 years. Using the Arizona State University Dental Anthropology System to record traits and multivariate statistics to estimate biological affinities, Al Khiday is comparable to several Holocene samples, yet also highly divergent from contemporaneous Lower Nubians. Thus, population continuity is indicated after all, but with late Pleistocene Upper—rather than Lower Nubians as originally suggested—assuming dental traits are adequate proxies for ancient DN

Topiramat w profilaktyce migreny: dane uzyskane na podstawie analizy zbiorczej i otwartego badania obserwacyjnego

Topiramat zarejestrowano do profilaktycznego leczenia migreny w kilku krajach na podstawie wyników trzech dużych badań randomizowanych, przeprowadzonych metodą podwójnie ślepej próby, w których wykazano, że skuteczność tego leku była znacząco większa niż placebo. Autorzy dokonali przeglądu wyników dwóch badań. W jednym z nich wykorzystano połączone dane z trzech badań kontrolowanych, przeprowadzonych metodą podwójnie ślepej próby, w których stosowano topiramat w dawce 100 mg, natomiast drugie stanowi kontynuację dwóch z wymienionych badań, w formie otwartego badania obserwacyjnego, w którym pacjenci otrzymywali różne dawki topiramatu przez 8 miesięcy w ramach leczenia podtrzymującego. Uzyskane wyniki potwierdzają, że topiramat skutecznie zmniejsza częstość migrenowych bólów głowy i wykazuje korzystny profil bezpieczeństwa

The Khartoum-Omdurman conurbation : a growing megacity at the confluence of the Blue and White Nile Rivers

Khartoum is one of the largest cities in Africa, located immediately south of the junction of the Blue and White Nile rivers in central Sudan. The growth of the Greater Khartoum-Omdurman conurbation arose \uac\u2013 without a proper urban plan \u2013 from the agricultural wealth created through the completion of three major dams in 1925, 1937 and 1966, and mostly in the last three decades. Urban expansion was enabled by and helped to enhance the major agricultural expansion of the Gezira clay plains located to the south between the lower Blue and White Nile rivers. The confluence of the Blue and White Nile has been a focus of human settlement for at least 8,000 years, initially by semi-sedentary groups with a fishing-hunting-gathering lifestyle and later by Neolithic groups as shown by hundreds of archaeological sites. Today, Khartoum is a desert city and the hottest capital city on Earth, still very vulnerable to floods triggered by intense convectional storms. Such extreme events may become more common in future, representing a major geomorphological hazard in a city developed without urban plans. Moreover, uncontrolled urban and agricultural development is threatening most of the prehistoric cultural heritage of the region

An automated system for the objective evaluation of human gustatory sensitivity using tongue biopotential recordings

The goal of this work is to develop an automatic system for the evaluation of the gustatory sensitivity of patients using an electrophysiological recording of the response of bud cells to taste stimuli. In particular, the study aims to evaluate the effectiveness and limitations of supervised classifiers in the discrimination between subjects belonging to the three 6-n-pro-pylthiouracil (PROP) taster categories (supertasters, medium tasters, and non-tasters), exploiting features extracted from electrophysiological recordings of the tongue. Thirty-nine subjects (equally divided into the three PROP status classes by standard non-objective scaling methods) underwent a non-invasive, differential, biopotential recording of their tongues during stimulation with PROP by using a custom-made, flexible, silver electrode. Two different classifiers were trained to recognize up to seven different features extracted from the recorded depolarization signal. The classification results indicate that the identified set of features allows to distinguish between PROP tasters and non-tasters (average accuracy of 80% ± 18% and up to 94% ± 15% when only supertasters and non-tasters are considered), but medium tasters were difficult to identify. However, these apparent classification errors are related to uncertainty in the labeling procedures, which are based on non-objective tests, in which the subjects provided borderline evaluations. Thus, using the proposed method, it is possible, for the first time, to automatically achieve objective PROP taster status identification with high accuracy. The simplicity of the recording technique allows for easy reproduction of the experimental setting; thus the technique can be used in future studies to evaluate other gustatory stimuli. The proposed approach represents the first objective and automatic method to directly measure human gustatory responses and a milestone for physiological taste studies, with applications ranging from basic science to food tasting evaluations