Decrease of attention and an possible micro-sleep of an artificial system operator is very dangerous and its early detection can prevent great losses. This article deals with a classification of States of vigilance based on the analysis of an electroencefalographic activity of the brain. Preprocessing of data is done by the Discrete Fourier Transform. For the recognition radial basis functions (RBF), a k-nearest neighbor and a method based on the Bayesian theory is used. Its coefficients are found using the maximum likelihood estimation. An experiment with recognition of 6 States of vigilance created according to reaction time is performed.
Východiska: Předkládaný způsob hodnocení počítačových testů vychází z potřeby snížit riziko tipování správných odpovědí při testování velkého množství studentů zdravotnických oborů. Systém vede studenty k uvědomování si svých chyb a odečítá body za neuvědomělé chyby. Cíl: Porovnat vhodnost metody testu s mírou jistoty oproti testu bez korekce tipování při hodnocení znalostí studentů zdravotnických oborů. Metody: Znalostní test průběžného hodnocení látky z anatomie podstoupilo 150 studentů. Jednalo se o počí- tačem hodnocených 40 dichotomických úloh s korekcí na hádání pomocí míry jistoty. Výsledky byly přepo- čítány na korekci pomocí odečtu bodu a na výsledky bez korekce. Výsledky: Průměrná hodnota obtížnosti testových položek Q dosahovala hodnoty 22,3. Přesto s korekcí výsledku pomocí míry jistoty byl medián 49,2 % z požadovaných 70 %. Bez korekce byl medián výsledku testu 77,5 %. Závěry: Hodnocení pomocí míry jistoty se zdá být ke studentům příliš přísné, avšak jestliže by studenti testovanou látku skutečně dobře ovládali, byli by úspěšní. Velkým přínosem oproti jiným korekčním mechanismům na hádání je větší stratifikace výsledků podle míry neuvědomělých chyb a otipovaných odpovědí., Background: The presented method of evaluating computer tests is based on the requisite to reduce the risk of guessing the correct answers while testing a large number of Healthcare students. The system guides students to realize their own mistakes and deducts points for their mistakes made unconsciously. Aim: To compare the suitability of a method dealing with the certainty based marking tests in contrast to the tests without correction of guessing the correct answers while marking the knowledge of students of health studies. Methods: 150 students undertook a test evaluating their level of knowledge from anatomy which is taken on regular basis. This test had a form of 40 computer evaluated dichotomous tasks with the correction of guessing the correct answers with a degree of certainty. The results were recalculated for correction using a negative marking and for results without correction. Results: The average value of the difficulty of test items Q reached the level of 22.3. Yet corrected using the degree of certainty the outcome median was 49.2% of the required 70%. Without corrections the median was 77.5%. Conclusion: This evaluation using the degree of certainty seems to be too strict for the students, however if the students actually had the required knowledge, they would have been more successful. A great benefit compared to other correction mechanisms designed for guessing is greater stratification of the results according to the number of mistakes made unconsciously and guessed answers., Vít Blanař, Jan Pospíchal, and Literatura
A new genus, Vindobonella gen. n. (Acerentomidae s. l.), and a new species, Vindobonella leopoldina sp. n., are described from Vienna. The new genus belongs to a group characterized by a reduced labial palp and a non-modified striate band on abdominal segment VIII.
Specimens of Viola elatior (VE), V. pumila (VP) and V. stagnina (VS) in 40 Austrian, Czech and Slovak public herbaria were revised, a total of almost 1750 specimens from the three countries. Apart from VE, the quality of the original identifications was rather poor, especially of VS, which was frequently confused with VP and V. canina. This, together with the confusion of nomenclature that persisted during the 19th century, made the old literature records unreliable. Hybrids are usually difficult to identify and are rarer than generally believed. VS and VP have similar distribution patterns: they occur mainly on floodplains of large lowland rivers and in adjacent hills in the N part of Bohemia, S and Central Moravia, E Austria and S Slovakia; they may be classified as river corridor plants. VS differs from VE and VP mainly by its presence in S Bohemia and its absence from large parts of S Slovakia, as well as its rarity in Austria and Slovakia. All three species grow predominantly in regions with a relatively warm and dry climate: most localities are situated in regions with a mean annual temperature of 7–11 °C and mean annual precipitation 401–700 mm. A temporal analysis of records revealed that all three species are declining in all three countries: generally, this decline is weakest in Austria, with 46–61% of grid cells with occurrences confirmed after 1980 (compared with the number of grid cells with records for 1801–2008), and strongest in Slovakia, with 18–32% of grid cells with occurrences confirmed after 1980. The decline is due mainly to the canalization of rivers and subsequent changes in land use, urbanization and recently afforestation. VE may also be endangered by modern forestry practices. The inclusion of all three species in national Red Lists and subsequent conservation measures are justified and necessary, though national Red List status may differ between countries.
The entropy region is a fundamental object of study in mathematics, statistics, and information theory. On the one hand, it involves pure group theory, governing inequalities satisfied by subgroup indices, whereas on the other hand, computing network coding capacities amounts to a convex optimization over this region. In the case of four random variables, the points in the region that satisfy the Ingleton inequality (corresponding to abelian groups and to linear network codes) form a well-understood polyhedron, and so attention has turned to Ingleton-violating points in the region. How far these points extend is measured by their Ingleton score, where points with positive score are Ingleton-violating. The Four-Atom Conjecture stated that the Ingleton score cannot exceed 0.089373, but this was disproved by Matúš and Csirmaz. In this paper we employ two methods to investigate Ingleton-violating points and thereby produce the currently largest known Ingleton scores. First, we obtain many Ingleton-violating examples from non-abelian groups. Factorizability appears in many of those and is used to propose a systematic way to produce more. Second, we rephrase the problem of maximizing Ingleton score as an optimization question and introduce a new Ingleton score function, which is a limit of Ingleton scores with maximum unchanged. We use group theory to exploit symmetry in these new Ingleton score functions and the relations between them. Our approach yields some large Ingleton scores and, using this methodology, we find that there are entropic points with score 0.09250007770, currently the largest known score., Nigel Boston and Ting-Ting Nan., and Obsahuje bibliografické odkazy