The presented method reconstructs a network (a graph) from AIS data, which reflects vessel traffic and can be used for route planning. The approach consists of three main steps: maneuvering points detection, waypoints discovery, and edge construction. The maneuvering points detection uses the CUSUM method and reduces the amount of data for further processing. The genetic algorithm with spatial partitioning is used for waypoints discovery. Finally, edges connecting these waypoints form the final maritime traffic network. The approach aims at advancing the practice of maritime voyage planning, which is typically done manually by a ship’s navigation officer. The authors demonstrate the results of the implementation using Apache Spark, a popular distributed and parallel computing framework. The method is evaluated by comparing the results with an on-line voyage planning application. The evaluation shows that the approach has the capacity to generate a graph which resembles the real-world maritime traffic network.
The paper presents soil features and chemical composition in a self-heating coalwaste dump. The investigations were carried out in the Upper Silesian Coal Basin.A fire zone in which the soil temperature exceeded 50 C was selected for our study.Soil analyses were carried out for three grain sizesd > 1 mm, 0.063 mm < d ≤ 1 mm, and d ≤ 0.063 mmenabling identification of the diversity of the chemical composition in soil fractions. The highest concentration of heavy metals is represented by Mn (212-6972 mg kg -1 ), Zn (127-3283 mg kg -1 ), Pb (33.6-1344.7 mg kg -1 ), Cu (38.9-101.4 mg kg -1 ), and major elements by Fe (14,300-117,400 mg kg -1 ) and Ca (900-63,600 mg kg -1 ). Soil chemistry showed variations within individual studied sites. The soil reaction ranges from acidic (4.3 in KCl and 5.26 in H 2 O) to moderate alkaline (7.96 in H 2 O and 7.31 in KCl), whereas TOC ranges from 1.21% to 14.60% and TN from 0.023% to 0.291%. The distribution of n-alkanes clearly showed a low degree of transformation of organic matter and characteristic high values of Pr/Ph ratio for humic coals and coal waste in the region. Grains with diameters greater than 1 mm exhibited completely different features than those of fractions smaller than or equal to 1 mm. High organic carbon content (14.60) was detected in the samples along with PAHs. The influence of fire on the chemical composition of all samples was identified using geochemical indicators. PCA analysis showed that the values of the variables were more closely correlated in finer grains than in the coarsest fraction.
The paper discusses limitations of analytical attainment of the attitude of a geological plane by using three non-collinear points. We present problems that arise during computing the orientation of a plane generated by almost collinear points. We referred these errors to floating-point arithmetic inaccuracies. To demonstrate the problem, we examined a surface of constant orientation. We used Delaunay triangulation to calculate its local orientation parameters. We introduced a new measure of collinearity applicable for collecting attitude of planar triangles. Using this measure we showed that certain planes generated by the triangulation cannot be treated as a reliable source of measurement. To examine the relationship between collinearity and orientation, we used a combinatorial algorithm to obtain all possible planes from the given set of points. A statistical criterion of rejecting almost collinear planes was suggested.
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