This article succeeds the former A. P. K nko’ and A. I. Kuzmina’ ubl t on titled "A mathematical model of urban distribution electro-network considering its future development" (electronic scientific ...and technical magazine "Science and education" No. 5, 2014).The article offers a model of urban power distribution network as a set of transformer and distribution substations and cable lines. All elements of the network and new consumers are determined owing to vectors of parameters consistent with them.A problem of the urban power distribution network design, taking into account a prospective development of the city, is presented as a problem of discrete programming. It is in deciding on the optimal option to connect new consumers to the power supply network, on the number and sites to build new substations, and on the option to include them in the power supply network.Two methods, namely a reduction method for a set the nested tasks of global minimization and a decomposition method are offered to solve the problem.In reduction method the problem of prospective development of power supply network breaks into three subtasks of smaller dimension: a subtask to define the number and sites of new transformer and distribution substations, a subtask to define the option to connect new consumers to the power supply network, and a subtask to include new substations in the power supply network. The vector of the varied parameters is broken into three subvectors consistent with the subtasks. Each subtask is solved using an area of admissible vector values of the varied parameters at the fixed components of the subvectors obtained when solving the higher subtasks.In decomposition method the task is presented as a set of three, similar to reduction method, reductions of subtasks and a problem of coordination. The problem of coordination specifies a sequence of the subtasks solution, defines the moment of calculation termination. Coordination is realized by introducing the vectors of parameters of limiting and stimulating coordination into the problem. Vector components of limiting coordination mean the minimum numbers of substations to be built. Vector components of stimulating coordination define "usefulness" of new substations to be built on possible sites. There are two offered options to determine parameters of stimulating coordination.The offered methods of reduction and decomposition generally generate a large number of the optimization algorithms. Subsequent publications are expected to consider these algorithms and a software to implement them.
Low ability of students solving the problems can be overcome by accustomed to work on Higher Order Thinking Skills (HOTS) which include analyzing (C4), evaluating (C5) and creating (C6). This study ...aims to find the distribution of Mathematics questions based on HOTS in integrated thematic textbooks in the 2013 curriculum. Its importance is to give an overview to the government, especially teachers about the quality of these books which are used by schools until 2021. This research is a content analysis with a qualitative approach. Data sources in this study are integrated thematic textbooks of Curriculum 2013 revised edition 2018 for grades I to III SD / MI. The data analysis technique uses percentage analysis. The results showed that the cognitive level of HOTS class I in C4 at 22%, C5 at 4%, C6 at 11%. Class II, C4 at 28%, C5 at 1%, C6 at 6%. Meanwhile, class III, C4 at 29%, C5 at 3%, C6 at 6%. In conclusion, HOTS mathematics questions on cognitive level C4, C5, and C6 in the thematic books of the 2013 curriculum for classes I, II, and III have not reached the criteria for good questions because the percentage of good questions for each cognitive level is C4 40%, C5 30% , and C6 by 30%.
The technology that has evolved can not be denied in fact has entered in every line of life. Not many of us are not familiar with a technology let alone which has been the topic of conversation ...since the last few years, call it with information tools such as smartphones. These tools can help in classroom learning activities. The problems that arise in learning how students need to use some new learning techniques and can visualize and can be taken anywhere. Students have difficulties in learning the mathematics of geometry a flat side room and this media is needed. The model used is Lee & Owens. The result of the research is a valid mobile learning media. Abstrak: Teknologi yang telah berkembang tidak bisa dipungkiri pada kenyataannya telah masuk dalam setiap lini kehidupan. Tidak banyak dari kita yang tidak mengenal suatu teknologi apalagi telah menjadi topik perbincangan sejak beberapa tahun terakhir, sebut saja dengan alat informasi, seperti smartphone. Alat tersebut dapat membantu dalam kegiatan pembelajaran di kelas. Permasalahan yang muncul pada pembelajaran bagaimana siswa perlu menggunakan beberapa teknik belajar yang baru dan dapat memvisualkan serta dapat dibawa kemanapun. Siswa kesulitan mempelajari matematika bahasan bangun ruang sisi datar dan dibutuhkan media ini. Model yang digunakan yaitu Lee & Owens. Hasil penelitian berupa media mobile learning yang valid.
This study introduces the results of scientific research and pilot testing of modernised automated electric drives of the plate mill stands. The experimental tests of electromechanical systems of the ...reversing stand of the mill 5000 showed the intolerable level of dynamic loads when biting. The problem of reducing dynamic loads and elastic vibrations in shaft lines was stated; it can be solved through enhancing the automated electric drive. The method for limiting loads through biting metal with accelerated rolls and compensating the dynamic component of speed was suggested. The functional diagram of the electric drive to implement the suggested method was designed. In order to study the suggested technical solution, the dynamic mathematic model of the mill stand electric drive with elastic coupling was developed. The results of modelling dynamic modes and experimental studies carried out on the mill 5000 were introduced. The operability and efficiency of the suggested solutions were substantiated.
This paper describes monocarboxylic acid extraction from aqueous solution experiments, using five types of mixed solvents and 12 monocarboxylic acids. From the results of these experiments, a new ...mathematical model, including a new definition of extractant's basicity (
p
K
a
,
BS
), was developed and validated. Trioctylamine (TOA)/1-octanol, TOA/methyl
iso-butyl ketone (MIBK), TOA/tetrachloromethane (
CCl
4
), trialkylphosphine oxide (TRPO) /1-octanol and TRPO/ kerosene, were used as the extractant, and formic, acetic, propionic, butyric, valeric, caproic, monochloroacetic, dichloroacetic, trichloroacetic, glycolic, glyoxylic, and lactic acids, were used as the solutes extracted. The relative basicity of the extractant to the solute extracted (
p
K
a
,
BS
) was measured in different extractant concentrations. The experimental result confirms the mathematic model to predict the extraction equilibrium more accurately.
p
K
a
,
BS
can represent the complicated solvating power of the dilute to the association compound, and depends on the extractant concentration and the type of extractant, diluent and solute.
Highlights • This model would be particularly important in developing countries. • Projection distance was applied to reduce X-ray projection related errors. • A simulation model based on X-ray is ...good for surgery of unstable pelvic fractures.
In new teaching-learning approaches, it is emphasized in meaningful learning versus rote learning .So assessment and evaluation as an inseparable part of the educational process should also be ...altered to suit the new educational approaches. One of the new tools for assessment and evaluation of conceptual knowledge is conceptual scheme. Conceptual scheme contains concepts or phrases that are set in a circle or other geometric shapes and lines connecting with the significant relationship together. Conceptual scheme is a useful tool for education, curriculum development, assessment and evaluation of learning. In this study, using the conceptual scheme, understanding of 25 third-year students who major in mathematics teacher in the Shahid Rajaee Teacher Training University was evaluated about limit concept. After familiarizing students with the conceptual scheme in three stages, students come with software to draw a conceptual scheme of “limit” individually and in groups. The findings show that misunderstanding and errors was reduced at each stage compared to a previous stage. Width and length relations get closer, more, and more complex respectively. Some misunderstanding of students that were identified in this way includes: (2) Definition of limit to a point where some students thought that the point should be in the function domain. (2)Some of them knew “limit’ ’for sequence divergence. (3)All asymptotic have not stated using the limit. Identify the misunderstanding of students using the traditional tools of evaluation was not possible. Moreover, according to the standard connections in learning, the relationship represents a deeper conceptual understanding of the concept when relations increase. The results can provide a basis for revision of assessment methods and improving the quality of educational designin.
We analyze edge dominating set from a parameterized perspective. More specifically, we prove that this problem is in \documentclass12pt{minimal}
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Hollow fiber renewal liquid membrane(HFRLM) method was proposed based on the surface renewal theory for removal of aniline from waste water. The system of aniline + D2 EHPA in kerosene + HCl was ...used. Aqueous layer diffusion in the feed phase is the rate-control step, and the influence of lumen side flow rate on the mass transfer is more significant than that on the shell side. The resistance of overall mass transfer is greatly reduced because of the mass transfer intensification in the renewal of liquid membrane on the lumen side. The driving force of mass transfer can be considered as a function of distribution equilibrium, and the overall mass transfer coefficient increases with the increase of p H in the feed solution, HCl concentration and D2 EHPA concentration, and decreases with the increase of initial aniline concentration. A mass transfer model is developed for HFRLM based on the surface renewal theory. The calculated results agree well with experimental results. The HFRLM process is a promising method for aniline wastewater treatment.
The present situation of crisis in the economic of Russian Federation made impossible further realization of widespread investment building projects based on originally credits and made the most ...important to find new strategies of surviving and development of construction which are adequate to the modern realms of building market. Any project of underground construction may be looked like huge investment development project depended on the logic of its realization. Building of optimal strategy of project should be started with assumption that nobody can create their strategy acts of others mates of a project. With the game theory developer takes the opportunity to predict steps of his mates and opponents. The hard instrumentary should be used only in the case of very important strategy decisions. The mathematic modelizing is very useful instrument of solving problems of management of investment building project. The most simple optimizing and game theory models which sets the available directions searches in this space was described in this work. The ecomic-mathematical model lets to find optimal prices of real estate according to opportunities of paying their bills at the level of single development company, also the optimal financial strategy in the situation of economic crisis. Game theory models in common form describes opponents relationships between development companies and game theory models in a form of characteristic functions describes cooperation relationship between developments, as union of resources, merger, and absorption. Ierarchic game models represent the relationship between developments and banks (investors) or developers and providers and of course serve as a foundation for management of stable development of investment building complex of a region.
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