Статьи журнала - Сибирский аэрокосмический журнал
Все статьи: 3183
"Образ" и "персонаж" в искусстве и философии
Статья научная
Систематизируются научные исследования по заявленной теме. Содержится авторская концепция «двух типов духовности», влияющих на «два проекта» в науке и искусстве.
Бесплатно
Статья научная
Nowadays tree modeling algorithms are used in different fields of activity: from computer games to the plantation forest management. Tree modeling algorithm parameters can depend on different factors: it could be features of land- scape, climate or geographical location. Depending on the tasks to be solved, the detail level of the created model is chosen. Forest management tasks often do not require a high detail level, it is sufficient to construct a schematic plantation model. For computer games the creation of photorealistic models is required. The paper proposes an algorithm of 3D tree modeling which consists of the following steps: first step - building a tree framework (modeling the growth of a tree and adding new nodes), while under the framework is meant a set of three-dimensional vectors with attributive data for each vector; then building a tree and overlaying textures. The trunk and branches of the modeled tree are approximated by truncated cones, the axes of which are the vectors of the frame. The tree model constructing algorithm is iterative. Every iteration is a tree growth stage. Thus, the tree is gradually grown to the required level. The developed algorithm allows modeling trees of different state categories. The feature of the proposed algorithm is the possibility of constructing a three-dimensional tree model with any detail level. For example, for coniferous trees it is possible to built a tree up to each needle.
Бесплатно
6-апериодические слова над трехбуквенным алфавитом
Статья научная
Работа посвящена изучению множеств апериодических слов над конечным алфавитом. Множество таких слов можно рассматривать как некоторый конечный формальный язык. У. Бернсайд задал вопрос о локальной конечности периодических групп. Отрицательный ответ был получен лишь через шестьдесят лет Е. С. Голодом. Вскоре С. В. Алешиным, Р. И. Григорчуком, В. И. Сущанским были построены еще примеры, подтверждающие отрицательный ответ на вопрос Бернсайда. Конечность свободной бернсайдовской группы периода n установлена в разное время для периодов два и три (У. Бернсайд), для периода четыре (У. Бернсайд; И. Н. Санов), для периода шесть (М. Холл). Бесконечность такой группы, для нечетных показателей, превышающих 4381, установлена в работе П. С. Новикова - С. И. Адяна (1967), а для нечетных показателей, превышающих 664, - в монографии С. И. Адяна (1975). Геометрический метод доказательства для нечетных показателей, превышающих 1010, принадлежит А. Ю. Ольшанскому (1989). В данной статье рассматриваем множество 6-апериодических слов. l-апериодическим словом называется слово Х, не содержащее нетривиальных подслов типа Yl. В книге С. И. Адяна (1975) имеется обоснование С. Е. Аршона (1937) того, что в двухбуквенном алфавите имеется бесконечно много три-апериодических слов любой длины. В книге А. Ю. Ольшанского (1989) приведено доказательство бесконечности множества шесть-апериодических слов и получена оценка количества таких слов любой данной длины. Здесь мы хотим оценить функцию количества шесть-апериодических слов любой данной длины в алфавите из трех букв. Полученные результаты могут быть полезны при кодировании информации в сеансах космосвязи.
Бесплатно
Другой
Бесплатно
A comprehensive evolutionary approach for neural network ensembles automatic design
Статья научная
A new comprehensive approach for neural network ensembles design is proposed. It consists of a method of neural networks automatic design and a method of automatic formation of an ensemble solution on the basis of separate neural networks solutions. It is demonstrated that the proposed approach is not less effective than a number of other approaches for neural network ensembles design.
Бесплатно
A mathematical model of oil price assessment
Статья научная
The article deals with the development of the mathematical model of oil price assessment. The methodological foundation is determined for developing the mathematical model: two axioms stating the unique properties of oil as a commodity. The first one claims that oil is a commodity being determined at auctions and is not related to its value as a measure of abstract labor invested, the second axiom states that the markdown in oil price will not cause the increase in the demand for it, as the demand is determined only by the economy state of the demander. Among the factors of oil pricing an imbalance of oil supply and demand in the world market is chosen to be the dominant factor. The mathematical model is represented in two models. The first one assumes that for any excess of supply over demand, the price of oil tends to zero, i. e. for a sufficiently large number of auctions it becomes lower than any predefined level. The second theorem states that in the case of the excess of demand over supply oil price tends to infinity (a finite number of sessions exceeds any predefined level) in case of the dominance of imbalance. The most likely forecast resulting from the hypothesis that the developed mathematical model is correct is the trend of the price decrease reaching its extremely low level and a further transition into a long-term period characterized by the price increase trend.
Бесплатно
A method of image segmentation with the help of areas growing and multiscale analysis
Статья научная
In this article we analyzed advantages and disadvantages of existing methods of image segmentation. The development of an original algorithm of segmentation which uses the method of areas growing and multi scale analysis is presented. The capabilities of this method in different images segmentation are researched.
Бесплатно
A model to assess the risk of bankruptcy for agricultural firms in Krasnoyarsk region
Статья научная
In this paper we report on the algorithm of development of a bankruptcy risk assessment model to be applied to agricultural firms of Krasnoyarsk region, which involves factorial and discriminant analysis of relevant data.
Бесплатно
A multidimensional analog of the Cooley-Tukey FFT algorithm
Статья научная
In this article a recurring sequence of orthogonal basis in the n-dimensional case has been applied to derive formulas of n-dimensional fast Fourier transform algorithm, which uses Complex multiplication and nN n log 2 N complex addition; where N = 2 s – is a number of counts on one of the axes.
Бесплатно
A new fast face detection technique
Статья научная
The problem of human face detection in a natural or artificial environment has always been among the highest priorities for researchers working in the field of computer vision systems and artificial intelligence. An effective face detection system should provide high percentage of correct detections, and low false detection rate in short time. Viola-Jones method is one of the best algorithms in terms of speed/quality ratio. However, this method in many cases gives a large number of false detections. The color of human skin is one of the features that helps to make face detection. The presence of the color information improves the efficiency of face allocation; narrows the search area and reduces the number of false detections and processing time of the input images. This paper solved is the problem face area detection, based on two new methods. The first technique uses the image pixel skipping process instead of testing each pixel to label it as skin or non-skin by using RGB color space. Second technique uses YCbCr color space and block approach which divides the image into blocks, the size of each block is 3×3 pixels, then we check the central pixel. If the central pixel satisfies the skin criteria, the whole block will be considered as a skin. Finally, we applied Viola-Jones algorithm to detect faces. The experimental results presented in the paper shows that the proposed algorithms provide high speed detection at low false error rate.
Бесплатно
A new method for natural language call routing problem solving
Статья
Natural Language call routing remains a complex and challenging research area in machine intelligence and language understanding. This paper is in the area of classifying user utterances into different categories. The focus is on design of algorithm that combines supervised and unsupervised learning models in order to improve classification quality. We have shown that the proposed approach is able to outperform existing methods on a large dataset and do not require morphological and stop-word filtering. In this paper we present a new formula for term relevance estimation, which is a modification offuzzy rules relevance estimation for fuzzy classifier. We propose to split the classification task into two steps: 1) “garbage” class identification; 2) further classification into meaningful classes. The performance of the proposed algorithm is compared to several standard classification algorithms on the database without the “garbage” class and found to outperform them with the accuracy rate of 85,55 %. Combination of our approach with 9-NN algorithm for two-stage classification problem definition provides the accuracy rate of 77,11 % for test sample at whole.
Бесплатно
Статья научная
In order to simulate the Vaganov–Shashkin model for seasonal growth and tree-ring formation, a solution algorithm for the parameterization problem of the model is being proposed in cases, when a modulation is possible. The algorithm is realized as dll-library (or as a text file), tested on extensive data. A concept of difference in criterion between the actual tree-ring chronology and its model is introduced. Two new difference criteria are developed.
Бесплатно
A practical approach to software portability
Статья научная
This paper describes an approach to porting onboard software for communication and navigation satellites to new platforms that use various onboard computers and devices. The approach relies on the target(onboard) and the tool software stratification and strong typing and the Modula-2 programming language especial features.
Бесплатно
Статья научная
In this article we have considered a possibility to use the commercial XBO xenon lamps to create a source of radiation, integrated in solar simulators. We have conducted experimental studies of photonic lamp performance.
Бесплатно
About multiagent system applications for speech recognition problem
Статья научная
In this paper we suggest two different multi agent systems for speech recognition problem. The multi agent systems (MAS) are becoming very popular because of their flexibility and applicability to complex problems. The system is based on functioning of different agents that forms the system and interacts with each other. The main profit of using multi agent approach is that every agent can be described as a simple subsystem and the whole initial task can be solved with automatic and autonomous agent actions, interactions and decision making. So the main problem can be reduced to behavior rule base tuning.
Бесплатно
About non-parametric identification of T-processes
Статья научная
This paper is devoted to the construction of a new class of models under incomplete information. We are talking about multidimensional inertia-free objects for the case when the components of the output vector are stochastically dependent, and the character of this dependence is unknown a priori. The study of a multidimensional object inevitably leads to a system of implicit dependencies of the output variables of the object from the input variables, but in this case this dependence extends to some components of the output vector. The key issue in this situation is the definition of the nature of this dependence for which the presence of a priori information is necessary to some extent. Taking into account that the main purpose of the model of such objects is the prediction of output variables with known input, it is necessary to solve a system of nonlinear implicit equations whose form is unknown at the initial stage of the identifica- tion problem, but only that one or another output component depends on other variables which determine the state of the object. Thus, a rather nontrivial situation arises for the solution of a system of implicit nonlinear equations under condi- tions when there are no usual equations. Consequently, the model of the object (and this is a main identification task) cannot be constructed in the same way as is accepted in the existing theory of identification as a result of a lack of a priori information. If it was possible to parametrize the system of nonlinear equations, then at a known input it would be necessary to solve this system, since in this case it is known, once the parameterization step is overcome. The main content of this article is the solution of the identification problem, in the presence of T-processes, and while the pa- rametrization stage can not be overcome without additional a priori information about the process under investigation. In this connection, the scheme for solving a system of non-linear equations (which are unknown) can be represented in the form of some successive algorithmic chain. First, a vector of discrepancies is formed on the basis of the available training sample including observations of all components of the input and output variables. And after that, the evalua- tion of the output of the object with known values of the input variables is based on the Nadaraya-Watson estimates. Thus, for given values of the input variables of the T-process, we can carry out a procedure of estimating the forecast of the output variables. Numerous computational experiments on the study of the proposed T-models have shown their rather high effi- ciency. The article presents the results of computational experiments illustrating the effectiveness of the proposed tech- nology of forecasting the values of output variables on the known input.
Бесплатно
About parametric identification algorithms of discrete-continuous processes
Статья научная
Researches presented in the paper are devoted to parametric modelling of multidimensional processes of discrete- continuous type in the condition of priori information lack. Similar processes occur in the space industry, for example, in the manufacture of products based on electronic components. The article considers multidimensional processes with unknown mathematical description. Using parametric approach, we choose the structure of investigated process with the accuracy to within parameters, and the next step is to estimate the model parameters from the available sample of observations of the process input and output variables. The paper examines the case when due to the lack of priori knowledge about the object an error is allowed at the stage of parametric structure choosing. The relative approxima- tion error is used to estimate the model accuracy, which shows the difference between model and object outputs. A comparative analysis of several parametric models for one investigated object is carried out is. Using the method of least squares we obtain estimates of the parameters. The paper presents the results of a series of computational experiments illustrating the dependence of the modelling error on the object noise level, as well as on the sample size of observations of the input and output variables. One of the obvious parametric models advantages is the ease of its applying. However, if the dimension of the input variables vector is high, the process has a complex structure, and there is no priori information about the object structure, then it is difficult to use parametric methods. In this case, it is advisable to use nonparametric identification methods. In this paper we use a nonparametric estimation of the regression function on observations of Nadaraya-Watson as an estimate of the process output variable. However, such estimates require a large number of initial data, also they are sensitive to various kinds of defects in the initial samples of observations. Besides that, the paper compares nonpara- metric model with parametric one for the investigated process.
Бесплатно
Статья
The optimal control problem for nonlinear dynamic systems is considered. The proposed approach is based on both partially analytical and partially numerical techniques of the optimal control problem solving. Optimal control problem is reduced to unconstrained extremum problem, which is related to seeking for the initial point of the co-state variables that would satisfy the boundaries. To solve the optimization problem, well-known global optimization techniques are suggested and compared. The performance of the evolutionary strategies algorithm was increased by implementing the special restarting condition in the scheme.
Бесплатно
About the analysis of the pulse-width system with feedback
Статья научная
In the article research results of the pulse-width system (PWS) captured by a negative feedback circuit have been depicted. Based on an asymptotic method of order decrease in the linear part of system, we have offered a technique for decreasing the PWS to an equivalent nonlinear pulse-amplitude system for which known methods of research are applied.
Бесплатно
Статья научная
Using feature selection procedures based on filters is useful on the pre-processing stage for solving the task of data analysis in different domains including an air-space industry. However, it is a complicated problem, due to the absence of class labels that would guide the search for relevant information. The feature selection using “wrapper” approach requires a learning algorithm (function) to evaluate the candidate feature subsets. However, they are usually performed separately from each other. In this paper, we propose two-stage methods which can be performed in supervised and unsupervised forms simultaneously based on a developed scheme using three criteria for estimation (“filter”) and multi-criteria genetic programming using self-adjusting neural network classifiers and their ensembles (“wrapper”). The proposed approach was compared with different methods for feature selection on tree audio corpora in German, English and Russian languages for the speaker emotion recognition. The obtained results showed that the developed technique for feature selection provides to increase accuracy for emotion recognition.
Бесплатно
