Theoretical Study and Numerical Experiment on the Influence of Trend Changes on Correlation Coefficient

When one of two time series undergoes an obvious change in trend, the correlation coefficient between the two will be distorted. In the context of global warming, most meteorological time series have obvious linear trends, so how do variations in these trends affect the correlation coefficient? In this paper, the correlation between time series with trend changes is studied theoretically and numerically. Adopting the trend coefficient, which reflects the nature and size of the trend change, we derive a formula r = f(k, l) for the correlation coefficient of time series X and Y with respective trend coefficients k and l. Analysis of the function graph shows that the changes in correlation coefficient with respect to the trend coefficients produce a twisted saddle surface, and the saddle point coordinates are given by the trend coefficients of time series X and Y with the opposite signs. The curve f(k, l) = f(0, 0) divides the coordinate planes into regions where f(k, l) > f(0, 0) and f(k, l) < f(0, 0). When the trend coefficients k and l are very small and the correlation coefficient is also very small, then k > 0 and l > 0 (or k < 0 and l < 0) amplifies a positive correlation, whereas k > 0 and l < 0 (or k < 0 and l > 0) amplifies a negative correlation, as found in previous research. Finally, experiments using meteorological data verify the reliability and effectiveness of the theory.

geoGAT: Graph Model Based on Attention Mechanism for Geographic Text Classification

In the area of geographic information processing, there are few researches on geographic text classification. However, the application of this task in Chinese is relatively rare. In our work, we intend to implement a method to extract text containing geographical entities from a large number of network texts. The geographic information in these texts is of great practical significance to transportation, urban and rural planning, disaster relief, and other fields. We use the method of graph convolutional neural network with attention mechanism to achieve this function. Graph attention networks (GAT) is an improvement of graph convolutional neural networks (GCN). Compared with GCN, the advantage of GAT is that the attention mechanism is proposed to weight the sum of the characteristics of adjacent vertices. In addition, We construct a Chinese dataset containing geographical classification from multiple datasets of Chinese text classification. The Macro-F Score of the geoGAT we used reached 95% on the new Chinese dataset.

Teaching Function Graphs To Students Using Educational Methods

This article highlights the role of educational technologies and some recommendations related to developing students 'interest in mathematics through the use of interactive learning technologies in drawing function graphs, quickly and meaningfully mastering the full verification stages before describing a function graph, and developing students' independent and creative abilities in the learning process.

The assessment of the spatial ontogenetic structure of the coenopopulation Oxytropis floribunda (Pall.) DC. in undisturbed coenoses (on the territory of the Samara Region)

Data on the peculiarities of rare plants coenotic populations organization in petrophytic steppes make a certain contribution to the development of theoretical issues of phytocoenology, bioecology and nature protection. Coenopopulations of Oxytropis floribunda (Pall.) DC. are monitored on the territory of the Samara Region (the natural monument Sernovodnyy Shikhan) in the course of the work. Population ontogenetic methods have been used, including methods of spatial statistics. The coenopopulation of the species has been studied in the Stipa pennata Oxytropis floribunda community without any apparent anthropogenic load. It has been found that the total number of individuals of O. floribunda in the studied coenopopulation was 81 individuals, with a density of 6 individuals per 1 m. The phytogenic field strength coefficient is 0,06. The studied community is dominated by the pregenerative age states of O. floribunda. The coenopopulation of O. floribunda is generally characterized by a contagious type of spatial structure with the formation of aggregations of 0,41,2 m in size. The Ripley function graph for pregenerative plants has also showed the presence of clustering zones that occurs due to seed germination near the mother plants of the studied representative. Generative individuals of O. floribunda in the plant community are located randomly, which indicates favorable conditions for the growth of the species in this area.

METODE PICTURE AND PICTURE KARTU GRAFIK FUNGSI SEBAGAI MEDIA PEMBELAJARAN MATEMATIKA SISWA KELAS IX MADRASAH TSANAWIYAH NEGERI 1 LANGKAT

The results of classroom action research (PTK) show that the value acquisition has increased very well, where the results of this study use quantitative data analysis with 32 respondents from class IX-1 as samples, while data management uses the product moment formula and the t test. Picture And Picture function graph card as a medium for learning mathematics for grade IX students at Madrasah Tsanawiyah Negeri 1 Langkat, it can improve student learning outcomes in mathematics, this can be seen from the results of daily exams, the correlation of arithmetic results in the first cycle between pre-test scores (pre-test) with the block I test score of 0.798, and the t test of 7.262, and the correlation of the calculated results in the second cycle between the block I test score and the block II test score of 0.899, and the t test of 11.26, it can also increase student activity in mathematics This can be seen from the activity of students in participating in the mathematics learning process with a value of 88% attendance at the beginning of the action, increased to 95% attendance in the first cycle, and increased again to 100% attendance in the second cycle, because students enjoy making and playing graphic cards. Function, so that it is fun for students in learning mathematics. Keywords: Picture and Picture Method, Function Graphic Card, Mathematics Learning Media

The Error in Drawing Graphic of Quadratic Function in PBL Model by Using True or False Strategy with GeoGebra-Assisted

Quadratic function is one of the important topic in mathematics. The purpose of this study is to describe the mistakes made by students when drawing a quadratic function graph. In this research, the focus of the problem is what type of mistakes made by students in drawing a graph of quadratic functions. The form of error here referred to an error in doing the exercise of drawing quadratic function graph in learning with the PBL model using a true or false strategy assisted by GeoGebra application. The conclusion of this research states that the error in drawing quadratic function graph is dominated by procedural errors. PBL model with true or false strategy with the help of GeoGebra application can be an alternative learning to overcome students' mistakes in drawing quadratic function graphs