Vladimir M. Bure

Soil acidity adaptive control problem

Problem of soil acidity regularization is modeled as stochastic adaptive control problem with a linear difference equation of the dynamics of a field pH level. Stochastic component in the equation represents an individual time variability of soil acidity of an elementary section. We use Bayesian approach to determine a posteriori probability density function of the unknown parameters of the stochastic transition process. The Kullback–Leibler information divergence is used as a measure of difference between true distribution and its estimation. Algorithm for the construction of an adaptive stabilizing control in such a linear control system is proposed in the paper. Numerical realization of the algorithm is represented for a problem of a field soil acidity control.

Methodology and tools for analyzing on-site data in precision agriculture

It is suggested to use all possible statistical analysis methods and then a comparative analysis of the results to increase the reliability of management decisions in precision agriculture.

Identification of homogeneous zones on a field based on yield of individual plots

A method is examined and an algorithm is proposed for identifying relatively homogeneous zones on a given agricultural field based on yield on its individual small plots. The initial information is formed automatically by means of harvesting machines equipped with yield sensors and global positioning system (GPS).

Consensus in a social network with two principals

This paper considers a model of opinion dynamics in a social network with two principals, in which the members may affect the opinions of each other and their opinions evolve according to a time-homogeneous Markov chain. We study the existence of a consensus in this network for two types of influence models, namely, when the principals may or may not affect the opinions of each other directly. In addition, we find the values of social network parameters under which a consensus is reached. For the cases without a consensus in its standard definition, we introduce the notion of a consensus of the majority and find the parameter values under which it is reached. Two numerical examples illustrate the obtained theoretical results.

Estimating passenger traffic characteristics in transport systems

This paper considers a statistical model of passenger flows between bus stops. By assumption, the intensities of incoming and outcoming passenger flows are known. We propose an estimation technique for the distribution of incoming passengers at a certain bus stop with respect to all successive bus stops. The simulation results based on natural experiments are also presented.

Passenger Traffic Evaluation and Price Formation on the Transportation Services Market

This paper investigates equilibrium formation in the passenger traffic model. First, we propose an estimation technique for the distribution of incoming passengers at each stop with respect to subsequent stops of a route based on available information on incoming and outgoing passengers. Second, we employ the obtained information on passenger traffic to introduce a game-theoretic model of passenger traffic distribution with respect to transport facilities.

Methods of cluster analysis for detection of homogeneous groups of healthcare time series

Statistical analysis is widely used for problem solving in different fields. We present a research on Saint Petersburg morbidity rate. The aim of the work is to detect the heterogeneity in districts of the city with respect to morbidity rate, which was chosen as an indicator of population health. Methods of cluster analysis was utilized for grouping districts to homogeneous sets. Clustering can be considered as an optimization problem as the distance between elements from the same group must be as little as possible, at the same time the distance between elements from different clusters must be as great as possible. Key feature of the research is that data are time dependent so it is necessary to use special dissimilarity measures. Besides each district is characterized by three values: children, teenagers and adult morbidity that call for multidimensional time series analysis. Firstly, a multidimensional clustering analysis was made. Then we conduct the analysis of children morbidity rate and propose a new dissimilarity measure for short time series.

Analysis of color characteristics of plants using aerial photography

One of the actual and demanded problems of contemporary precision agriculture is the determination of the state of agricultural plants. An accurate prediction of plant status during the growing period is necessary for the efficient use of fertilizers, low yields and high quality products. A method of this problem solution is based on the analysis of the optical characteristics of the plants on digital images. In this paper the method of color analysis of plants with aerial photos is considered. All calculations of the experiment were carried out using the language R.

A stochastic model of rumour spreading

In this paper, the new model for dynamics of spreading of rumour in a continuous time is suggested. Model depends on a parameter representing the probability of the outcome of interaction between the two spreaders. The process of spreading rumors is described by a system of linear differential equations.

Analysis of plants color characteristics using aerophotos with different factors of qualitative indicators

Одним из актуальных и перспективных направлений в современном точном земледелии является оценка состояния растений. Точная оценка состояния сельскохозяйственных растений в период вегетации необходима для эффективного использования удобрений, выгодной урожайности и высокого качества продукции. Метод решения этой задачи основан на анализе цветовых характеристик растений по цифровым изображениям. В работе рассмотрены методы анализа характеристик цвета растений по аэрофотоснимкам с разными факторами качественных показателей. Кроме того, представлен пример анализа экспериментальных данных с помощью языка программирования R. Исходными данными задачи являются цветовые параметры L, a, b растений на специальных тестовых площадках. Тестовая площадка представляет собой небольшой участок поля, на котором известны качественные показатели растений. Описан следующий пример: имеются тестовые площадки пшеницы с известными дозами азота (0, 60, 90, 120 кг действующего вещества на 1 га). Кроме того, на каждой площадке сформированы определенные качественные показатели растений: размер зерна (крупные, мелкие), защита растений (сорняки, без сорняков), нормы высева (6 млн на 1 га, 5 млн на 1 га). Необходимо проанализировать существование линейной зависимости между цветом растений и дозой азота в зависимости от разных качественных факторов. В ходе решения задачи разработаны и протестированы алгоритмы для реализации представленных методов. В результате предварительного анализа в описанном примере распределения выборок характеристик цвета по каждой паре факторов оказались различными. В ходе эксперимента были построены 8 линейных регрессий, преимущественно уравнения регрессий оказались статистически значимыми в целом. Тем не менее следует отметить, что коэффициент α при составляющей цвета L оказался равен 0. Предположительно это связано с ошибками во время закладки эксперимента (некоторая часть тестовых площадок была заложена позже остальных). Библиогр. 5 назв. Табл. 1. Ключевые слова: аэрофотосъемка, обобщенная характеристика цвета, точное земледелие, язык R.