Adaptation of gas-dynamic characteristic arrays to automated ballistics support of spacecraft flight

The current level of the design and use of new-generation spacecraft calls for a maximally automated ballistics support of engineering developments. An integral part of the solution of this problem is the development of an effective tool to adapt discrete functions of gas-dynamic characteristics to the solution of various problems that arise in the development and use of space complexes. Simplifying the use of bulky information arrays together with improving the accuracy of approximation of key coefficients will significantly improve the ballistics support quality. The aim of this work is to choose an optimum method for the approximation of a discrete function of two variable spacecraft aerodynamic characteristics. Based on the analysis of the advantages and drawbacks of basic methods of approximation by two fitting criteria: the maximum error and the root-mean-square deviation, recommendations on this choice were made. The methods were assessed by the example of the aerodynamic coefficients of the Sich-2M spacecraft’s simplified geometrical model tabulated as a function of the spacecraft orientation angles relative to the incident flow velocity. Multiparameter numerical studies were conducted for different approximation methods with varying the parameters of the approximation types under consideration and the approximation grid density. It was found that increasing the number of nodes of an input array does not always improve the accuracy of approximation. The node arrangement exerts a greater effect on the approximation quality. It was established that the most easily implementable method among those considered is a step interpolation, whose advantages are simplicity, quickness, and limitless possibilities in accuracy improvement, while its significant drawbacks are the lack of an analytical description and the dependence of the accuracy on the grid density. It was shown that spline functions feature the best approximating properties in comparison with other mathematical models. A polynomial approximation or any approximation by a general form function provide an analytical description with a single approximating function, but their accuracy of approximation is not so high as that provided by splines. It was found that there exists no approximation method that would be best by all criteria taken together: each method has some advantages, but at the same time, it has significant drawbacks too. An optimum approximation method is chosen according to the features of the problem, the priorities in approximation requirements, the required degree of approximation, and the initial data organization method.

Forecast of the development of an emergency at hydraulic structures of the Republic of Tatarstan

At present, a large number of hydraulic structures have been erected on the territory of the Republic of Tatarstan, which are classified as hydrodynamic hazardous facilities. Accidents at these facilities are sources of man-made emergencies. A number of hydraulic structures on the territory have been in operation without reconstruction for more than 70 years. The problem of ensuring the safety of hydraulic structures remains not fully understood and relevant today. Basically all hydraulic structures are located within or above settlements and are objects of increased risk. The consequences of a catastrophic flood can be aggravated by accidents at potentially dangerous facilities falling into its zone. The damage caused by such floods can amount to tens of millions of rubles. Incomplete destruction of the dam, when the safe operation of the structure is no longer possible, can lead to serious economic losses as a result of the cessation of energy production, hydraulic regulation and water collection in the reservoir. Careful monitoring is required in order to identify any possible emergencies. One of the solutions in this situation is the use of various methods for predicting emergency situations at hydraulic structures. In this regard, in the work, the authors have adapted a mathematical model based on Markov chains, which is distinguished by the efficiency of calculations and a high degree of approximation to statistical data. This model makes it possible to predict the state of hydraulic structures when the data on the water level and the volume of infiltration in the hydraulic structure changes. Based on the adapted model, the results of forecasting the water level for real hydraulic structures were obtained.

Anatomical cutting of gutted carcases of broiler chickens of the Smena-9 cross

The creation of a new cross “Smena-9” is aimed at reducing import dependence in the production of poultry products. In order to assess the meat raw material potential, morphological indicators of gutted carcasses of broiler chickens of the Smena-9 cross and individual parts were determined. The research used 5 carcasses of broilers from a batch of 38 days of age, weight, g: 1457.80; 1487.50; 1508.10; 1548.20; 1567.0. Separate parts – chest, thighs, drumsticks, legs and wings were anatomically divided into their components [muscles, skin, fat and bones with a residual lump]. The results of the experimental part of the research are reduced to average indicators: the average weight of a gutted carcass, individual parts and their components. It was found that the yield of the breast part is 36.0% [meat tissue 30.9%], the yield of the drumsticks – 29.9% [thighs – 16.45%, legs – 13.45%], wings – 10.75%, while flesh makes up 30.9%, 24.9%, and 7.8%, respectively, which exceeds the same indicators of domestic crosses. It was determined that the total yield of the breast and legs of the Smena-9 cross [65.9%] is higher by 5.3% for carcasses weighing 1600 g and by 8.8% for carcasses weighing 1850 g; for flesh, the excess is 5.8% and 5.2%, respectively. The obtained results serve as the basis for the development of normative documentation for parts of carcasses and their components of the Smena-9 cross and a system for assessing the effectiveness of equipment for cutting and deboning by the degree of approximation of the results of its operation to similar indicators for anatomical cutting and deboning.

Fatores intervenientes na mediação pedagógica Do tutor: o caso de um curso de graduação em administração pública PNAP/UAB

Este estudo apresenta os resultados de uma pesquisa qualitativa sobre fatores intervenientes na mediação pedagógica do tutor: o caso de um curso de Bacharelado em Administração Pública a distância (ADMP) do PNAP, ofertado por meio do Sistema UAB, em uma universidade pública da região Nordeste, iniciado em 2009. A questão norteadora foi: existem fatores que interferem na mediação pedagógica do tutor online? O objetivo foi identificar os fatores intervenientes e as múltiplas determinações que interferem na mediação pedagógica do tutor. A coleta de dados foi realizada por meio de questionário e de entrevista com os tutores online. Também foram observadas mensagens postadas no Ambiente Virtual de Aprendizagem (AVA). Participaram da pesquisa 11 tutores online, de um universo de 17 tutores que realizaram mediação pedagógica no curso pesquisado, entre 2012 e 2013. O resultado da pesquisa indica que fatores relacionados à qualidade do ensino; à qualidade dos materiais didáticos e materiais de apoio ao aluno; ao AVA; à infraestrutura física, tecnológica e administrativa disponível para os alunos e o grau de aproximação entre o professor e tutor interferem no desempenho do tutor online que atua no processo de ensino-estudo-aprendizagem do aluno da EAD ofertada com o uso da internet. Convém informar que o conteúdo deste artigo foi discutido em várias ocasiões em 2014 e 2015. Porém torna-se relevante retomar a discussão no campo da EAD devido ao momento pandêmico, no qual a mediação pedagógica foi intensificada, pelo fato das aulas presenciais terem sido, abruptamente, substituídas por aulas remotas e essa atividade passou a ser realizada também por professores e por monitores (alunos) selecionados para auxiliarem os professores nas atividades docentes no ensino remoto, semi-presencial ou totalmente online This study presents the results of a qualitative research on pedagogical factors involved in mediating the tutor : the case of the Bachelor in Public Administration Distance ( ADMP ) of PNAP offered through the UAB in a public university in northeastern Brazil System , initiated in 2009 and was motivated by question: There are factors that influence the mediation of the online tutor ? Their goal was to identify factors that affect the mediation of online tutor. To collect data, a questionnaire was administered and conducted an interview with the online tutors. Messages posted to the Virtual Learning Environment (VLE ) were also observed. Participated in the survey, 11 tutors online that was presents in the course researched, between 2012 and 2013 The research result indicates that the factors related to the quality of education; the quality of instructional materials and learner support materials; the quality of AVA; physical, technological and administrative available to students and the degree of approximation between the teacher and tutor; infrastructure interfere with the performance of the online tutor who works in the process: teaching - study - learning the of virtual student. It should be noted that the content of this article was discussed on several occasions in 2014 and 2015. However, it is relevant to resume the discussion in the field of DE due to the pandemic moment, in which the pedagogical mediation was intensified, due to the fact that the in-person classes were, abruptly, replaced by remote classes and this activity began to be performed also by teachers and monitors (students) selected to assist teachers in teaching activities in remote, semi-present or fully online teaching.

Modeling of engine thermal dynamics and its application in energy management of HEVs considering engine warming-up

The process of engine warming-up leads to additional fuel consumption. Energy management strategy considering engine warming-up is expected to further improve the energy economy of hybrid electric vehicles. This study provides a simple yet practical model for engine thermal dynamics. Then, the optimization problem of energy management considering engine warming-up is formulated on the basis of the control-oriented engine thermal dynamics. Thereafter, the optimal solution is derived by using the dynamic programming algorithm. Finally, the proposed engine thermal dynamics and energy management strategy are evaluated through simulation and experiments. Results show that the established engine thermal model effectively captures the main thermal behavior, simulation results reveal a high degree of approximation to experimental results for the engine temperature and fuel consumption, and the energy management strategy with engine temperature can further improve the energy efficiency.

On the degree of approximation of continuous functions by a specific transform of partial sums of their Fourier series

Using the Mean Rest Bounded Variation Sequences or the Mean Head Bounded Variation Sequences, we have proved four theorems pertaining to the degree of approximation in sup-norm of a continuous function f by general means τλn;A(f) of partial sums of its Fourier series. The degree of approximation is expressed via an auxiliary function H(t) ≥ 0 and via entries of a matrix whose indices form a strictly increasing sequence of positive integers λ := {λ(n)}∞n=1.

MODIFICATION OF SEPARATE RATIO TYPE EXPONENTIAL ESTIMATOR: A POST-STRATIFICATION APPROACH

In this research, modification of separate ratio type exponential estimator introduced in an earlier study is proposed. Expressions for the bias and mean square error (MSE) of the proposed estimator up to first degree of approximation are derived. The optimum value of the constant which minimize the MSE of the suggested estimator is also obtained. In the same vein, efficiency comparisons between the proposed estimator and some related existing ones under the case of post-stratification is conducted. Empirical studies have been conducted to demonstrate the efficiencies of the suggested estimators over other considered estimators. The proposed MSE and Percentage Relative Efficiency (PRE) were used to evaluate the achievement of the modified estimator.

Some Improved Estimators of Population Mean Under Systematic Sampling

Auxiliary information is very important in constructing estimators for the population parameters for increasing the efficiency different sampling schemes. In this paper, we consider the problem of estimation of population mean using information on auxiliary variables in systematic sampling. We derive the expressions for the bias and mean squared error (MSE) of the suggested estimators up to the 1st degree of approximation. Proposed estimators are compared with usual mean estimator in systematic sampling scheme theoretically as well as empirically.

Preserving the Shape of Functions by Applying Multidimensional Schoenberg-Type Operators

The paper presents a multidimensional generalization of the Schoenberg operators of higher order. The new operators are powerful tools that can be used for approximation processes in many fields of applied sciences. The construction of these operators uses a symmetry regarding the domain of definition. The degree of approximation by sequences of such operators is given in terms of the first and the second order moduli of continuity. Extending certain results obtained by Marsden in the one-dimensional case, the property of preservation of monotonicity and convexity is proved.