Automatic text classification is a very important task that consists in assigning labels (categories, groups, classes) to a given text based on a set of previously labeled texts called training set. The work presented in this paper treats the problem of automatic topical text categorization. It is a supervised classification because it works on a predefined set of classes and topical because it uses topics or subjects of texts as classes. In this context, we used a new approach based on $k$-NN algorithm, as well as a new set of pseudo-distances (distance metrics) known in the field of language identification. We also proposed a simple and effective method to improve the quality of performed categorization.
New type of aerodynamic tilting pad journal bearing was designed and successfully tested in several applications, one of which was power gyroscope support. Bearing design combines advantages of foil bearings, i.e. additional damping achieved by squeezing out gas film and friction of elastic elements on bearing casing surface, with qualities of classical tilting pad bearings, consisting in defined geometry of bearing gap and excellent stability. Theoretical solution of bearing characteristic calculation is shortly described, consisting in numerical solution of gas flow in narrow gap. Some computed data and results of experiments with rotors operated up to 180.000 rpm are presented too. and Obsahuje seznam literatury
This paper presents a hybrid probabilistic neural network (PNN) and particle swarm optimization (PSO) techniques to predict the soil liquefaction. The PSO algorithm is employed in selecting the optimal smoothing parameter of the PNN to improve the forecasting accuracy. Seven parameters such as earthquake magnitude, normalized peak horizontal acceleration at ground surface, standard penetration number, penetration resistance, relative compaction, mean grain diameter and groundwater table are selected as the evaluating indices. The predictions from the PSO-PNN model were compared with those from two models: backpropagation neural network (BPNN) model and support vector machine (SVM) model. The study concluded that the proposed PSO-PNN model can be used as a reliable approach for predicting soil liquefaction.
This paper describes some results of an experiment aimed at monitoring of contact fatigue during the axial bearings tests. The needful of AE set-up for measuring of signal and Axmat stand for testing is presented here. The measuring of some kind of bearings required the creation of new clamping elements (Segment and Bearing bush) to the existing key point of Axmat stand. The results in this paper show records in the time domain mainly for counts and events. These events are filtered by maximal amplitude for better response on signal changes during the lifetime record. For these evaluated records there are shown the final failures of tested bearings and possible causes of failures beginning. and Obsahuje seznam literatury
Tissue engineering is a very promising field of regenerative medicine. Life expectancy has been increasing, and tissue replacement is increasingly needed in patients suffering from various degenerative disorders of the organs. The use of adult mesenchymal stem cells (e.g. from adipose tissue or from bone marrow) in tissue engineering seems to be a promising approach for tissue replacements. Clinical applications can make direct use of the large secretome of these cells, which can have a positive influence on other cells around. Another advantage of adult mesenchymal stem cells is the possibility to differentiate them into various mature cells via appropriate culture conditions (i.e. medium composition, biomaterial properties, and dynamic conditions). This review is focused on current and future ways to carry out tissue replacement of damaged bones and blood vessels, especially with the use of suitable adult mesenchymal stem cells as a potential source of differentiated mature cells that can later be used for tissue replacement. The advantages and disadvantages of different stem cell sources are discussed, with a main focus on adipose-derived stem cells. Patient factors that can influence later clinical applications are taken into account.
We have evaluated the therapeutic effect of a compound mixture of caprylic acid (200 mg/kg fish), organic iron (0.2% of diet) and mannan oligosaccharide (0.4% of diet) in gilthead sea bream, Sparus aurata Linnaeus, infected with Sparicotyle chrysophrii Beneden et Hesse, 1863 in controlled conditions. One hundred and ten reared and S. chrysophrii-free fish (197 g) located in a cement tank were infected by the parasite two weeks following the addition of 150 S. chrysophrii-infected fish (70 g). Growth parameters and gill parasitic load were measured in treated against control fish after a ten-week-period. Differences in final weight, feed conversion ratio, specific growth rate and feed efficiency were not statistically significant between the experimental groups, suggesting no evident effect with respect to fish growth during the study period. Although the prevalence of S. chrysophrii was not affected by the mixture at the end of the experiment, the number of adults and larvae was significantly lower. The mean intensity encompassing the number of adults and larvae was 8.1 in treated vs 17.7 in control fish. Individual comparisons of gill arches showed that the preferred parasitism site for S. chrysophrii it the outermost or fourth gill arch, consistently apparent in fish fed the modified diet and in control fish. In conclusion, the combined application of caprylic acid, organic iron and mannan oligosaccharide can significantly affect the evolution of infection with S. chrysophrii in gilthead sea bream, being capable of reducing adult and larval stages of the monogenean. However, no difference in growth improvement was observed after the trial period, potentially leaving space for further optimisation of the added dietary compounds., George Rigos, Ivona Mladineo, Chrysa Nikoloudaki, Anamarija Vrbatovic, Dimitra Kogiannou., and Obsahuje bibliografii
A PC-based system with TV input for automatic tracking of a single and contrast object in 2D in a homogeneous and stationary environment has been developed and applied to Morris water maze experiments. Further development of the system aimed at broader support of experiments, reduction of requirements on the stationarity and homogeneity of the scene background and on multiple-object tracking is discussed. The computer control of active light markers of the tracked object applicable to multiple-objects tracking in a time-sharing regime is also mentioned in the conclusion. The latter extension of the system can be applied to kinematic studies in biomechanics, sport and rehabilitation medicine.
Weathering profiles in tropical regions usually present great heterogeneity and anisotropy of geological materials. High structural complexity and great bedrock irregularity are added when these profiles are composed of metamorphic rocks. Therefore, geological-geotechnical research initiatives in these regions imply indirect methods associated with direct methods. In this context, we studied the San Juan dam foundation in the Dominican Republic, geologically composed of young residual schist soil cover (up to 20 m), in which occurs schist layers of low resistance to SPT (2 SPT blows/30 cm) consistent with a massive and stratified marble rock, which tends to concentrate karst cavities. This geological condition, associated with the vast extent of the dam influence area, motivated the adoption of an indirect method by electrical resistivity intending to identify sites with the possibility of occurrence of cavities filled or not under the reservoir foundation and in the dam axis itself. Subsequently, a more rational initiative of mixed drillings was carried out in sites with such possibility, resulting in discarding these hypotheses and demonstrating that these cavities correspond to graphite schists and non-karst marbles, competent materials as dam foundation.
The study of mining-induced behaviors of faults and strata in underground coalmines is significant to know the mechanism and prediction of some accidents (i.e., water inrush, gas flowing and outburst). Equivalent materials are applied herein in an underground project to simulate a progressive mining operation with a normal fault occurrence. The failure–movement evolution of the overlying strata and the stress–displacement evolution of the fault are studied through a physical simulation test. The formation of a mining-induced fracture and the mechanism of accidents caused by the mining-induced fracture are analyzed. The results show that the footwall strata underwent a more notable movement compared to the hanging wall strata. Hence, the mining-induced fracture height of the footwall is higher than that of the hanging wall. The effect of the fault can be observed on the mining-induced fracture evolution of the footwall, hanging wall, and fault plane. The developed patterns of the fracture channel successively present an evolution in the shape of a “saddle”, a “trapezium”, and an “M”. The causes of accidents induced by the mining fracture are also discussed.
Distribution of the goods from a producer to a customer is one of the most important tasks of transportation. This paper focuses on the usage of genetic algorithms (GA) for optimizing problems in transportation, namely vehicle routing problem (VRP). VRP falls in the field of NP-hard problems, which cannot be solved in polynomial time. The problem was solved using genetic algorithm with two types of crossover, both including and leaving-out elitism, setting variable parameters of crossover and mutation probability, as well as prevention of creating invalid individuals. The algorithm was programmed in Matlab, tested on real world problem of spare parts distribution for garages, while the results were compared with another heuristic method (Clarke-Wright method). Genetic algorithm provided a better solution than the heuristic Clarke-Wright method.