32 research outputs found
Hydraulic fracture propagation model for porous media
No full textIn recent years, humanity became strongly dependent on the deep subsurface. It can be used as the energy source as well as the storage facility. At some stage, both listed applications require injection of fluid or gas into the subsurface porous media. Under certain conditions, it may provoke growth of hydraulic fractures. The appearance of fractures significantly changes properties of the permeable media which, in its turn, affects the operational performance of thesubsurface reservoir. Apart from that, hydraulic fracturing may also cause a nuisance to the human environment in the form of earthquakes. Ability to predict growth of hydraulic fractures and their geometry becomes crucial. For this purposes, numerical models are extensively used.In this work, a fully coupled hydro-mechanical model for hydraulic fracturing of porous media was proposed. Based on this model, an explicit computational framework was developed in C++ programming language allowing efficient modeling of a single fracture propagating. Proposed algorithm consists of the Discrete Fracture Model for multi-phase flow and contact-enriched Finite Element Model for geomechanics. Irwin’s failure criterion from Linear Elastic Fracture Mechanics concepts was adapted. Stress Intensity Factors are evaluated employing displacement extrapolation technique.The proposed model was extensively tested in various set-ups including single- and multi-phase flow in isothermal and thermal conditions. Both straight and turning fractures were modeled. Effects of the mesh geometry, material properties, and stress field anisotropy were analyzed in a series of tests. Obtained results were validated with the semi-analytical solutions. Proposednumerical scheme demonstrated its applicability to a wide range of tasks and showed a great potential for its extension to a larger group of applications.Geo-Engineerin
Guiding Deep Probabilistic Models
No full textDeep probabilistic models utilize deep neural networks to learn probability distributions in high-dimensional data spaces. Learning and inference in these models are complicated due to the difficulty of direct evaluation of the differences between the model distribution and the target. This thesis addresses this challenge and develops novel algorithms for learning and inference based on the guidance of complex parameterized distributions towards desired configurations via signals from auxiliary discriminative models.
In the first part of the thesis, we develop novel stable training objectives for Generative Adversarial Networks (GANs). We show that under standard unary-discriminator objectives, most of the valid solutions, where the learned distribution is aligned with the target, are unstable. We propose training objectives based on pairwise discriminators that provably preserve distribution alignment and demonstrate improved training stability in image generation tasks.
In the second part of the thesis, we introduce distribution support alignment as an alternative to the distribution alignment objective and develop a learning algorithm that guides distributions towards support alignment. We demonstrate the effectiveness of our approach in unsupervised domain adaptation under label distribution shift. Recent works have shown that under cross-domain label distribution shift, optimizing for distribution alignment is excessively restrictive and causes performance degradation. Our algorithm, which is based on support alignment, alleviates this issue.
In the third part of the thesis, we develop a novel approach to compositional generation in iterative generative processes: diffusion models and Generative Flow Networks (GFlowNets). Motivated by the growing prominence of generative models pre-trained at scale and the high training costs, we propose composition operations and guidance-based sampling algorithms that enable the combination of multiple pre-trained iterative generative processes. We offer empirical results on image and molecular generation tasks.Ph.D
Обоснование арендной платы за землю на основе материалов государственной кадастровой оценки земель
No full textВ данной научно-исследовательской работе проводится обоснование составных элементов расчета размера арендной платы за земли, находящиеся в государственной и муниципальной собственности, на основе материалов государственной кадастровой оценки земель на примере Ленинградской области РФ. В работе изучены теоретические положения кадастровой оценки земель и ее правового обеспечения, выявлены особенности арендной платы за земли, а также ее роль в формировании экономики страны, обоснованы корректирующие коэффициенты, необходимые для расчета арендной платы за землю и проведен сравнительный анализ удельных показателей кадастровой стоимости и базовых ставок арендной платы. Научно-исследовательская работа состоит из введения, трех глав, заключения, списка использованной литературы и приложений. В работе использовано 5 таблиц, 6 картосхем, 4 диаграммы, 3 блок-схемы, 2 приложения, 30 источников литературы. Количество страниц научно-исследовательской работы без приложений - 77.The research work focus on rationale of component elements of calculation land rent based on the state cadastral valuation of lands on example of Leningrad region. In the research work author analyzed theoretical positions of the state cadastral valuation of lands and its regulations, identified features of land rent and role of land rent in the formation of the state economy, correcting factors necessary for calculating the land rent are justified and analyzed a comparative analysis of specific indicators of cadastral value and basic rates of land rent. Research work consists of an introduction, three chapters, conclusion, a list of used literature and applications. In the research work 5 tables, 6 maps, 4 diagrams, 3 block diagrams, 2 applications, 30 sources of literature were used. Number of pages of research work without applications is 77
Crimes against justice committed in the pre-trial stages of criminal proceedings his parties and other persons: (theory and practice): autoabstract dissertation for the degree of master of laws: speciality 12.00.08 - criminal law and criminology; criminally-executive law
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Crimes against justice committed in the pre-trial stages of criminal proceedings his parties and other persons: (theory and practice): autoabstract dissertation for the degree of master of laws: speciality 12.00.08 - criminal law and criminology; criminally-executive law
No full textCrimes against justice committed in the pre-trial stages of criminal proceedings his parties and other persons: (theory and practice): autoabstract dissertation for the degree of master of laws: speciality 12.00.08 - criminal law and criminology; criminally-executive law
No full textDiscrete fracture model for simulating waterflooding processes under fracturing conditions
No full textIn our study, we develop a model for simulating fracturing processes in a poroelastic medium. The proposed approach combines the discrete fracture model enriched with contact plane mechanics. The model captures mechanical interactions of fractures and a deformable medium, fluid, and heat transfer in fractures and in a porous medium. Both effects of poroelasticity and thermoelasticity are accounted in our model. Mass and heat conservation equations are approximated by the finite volume method, and mechanical equilibrium equations are discretized by means of the Galerkin finite element approach. Two-dimensional grid facets between 3-dimensional finite elements are considered as possible fracture surfaces. Most of these facets are inactive from the beginning and are activated throughout the simulation. A fracture propagation criterion, based on Irwin's approach, is verified on each nonlinear iteration. When the criterion is satisfied, additional contact elements are added into finite element and discrete fracture model formulations respectively. The proposed approach allows modeling of existing natural and artificially created fractures within one framework. The model is tested on single- and multiple-phase fluid flow examples for both isothermal and thermal conditions and verified against existing semianalytical solutions. The applicability of the approach is demonstrated on an example of practical interests where a sector model of an oil reservoir is simulated with different injection and production regimes.</p
Resource Extraction from Territories of Indigenous Minority Peoples in the Russian North: International Legal and Domestic Regulation
No full textThe existing system of international legal and domestic protection of indigenous minority peoples’ interests in the Russian North concerning mining on their territories is analyzed in this article. This is an especially urgent issue due to the number of indigenous minority peoples in the Russian North who still keep to their traditional way of life (reindeer herding, hunting, fishing, and gathering). The article is drawn from the author’s personal experience and field work in the Russian North, where he met with local NGO leaders, authorities, and representatives of indigenous minority peoples (Nenets). The novelty of the work is that the author uses both legal analysis of source documents as well as empirical methods during the course of the research, and comes to conclusions which could have practical significance for Russian legislation
Provisions of the Indigenous and Tribal Peoples Convention, 1989 and other international documents in the field of idigenous peoples rights protection
No full textIn the article the analysis of the main international documents on indigenous people's rights protection is given. The basement of it is the ILO Convention on indigenous and tribal peoples, 1989. Author in his work retrace the dynamics of the formation and development of the international standards in this field, which gives us the possibility to watch the international law evolution, to determine its role in the contemporary system of the indigenous people's rights protection and to appraise its potential in future
Indigenous peoples' rights providing by international legal tools
No full textAccording to the UN data, more than 300 million people in the world today are indigenous people in more than 70 countries, many of which are on the verge of extinction. Being heirs of unique cultures and having a different social, economic and political lifestyle, they try to preserve their way of life in a society dominated by a completely different culture. Throughout history, their rights were constantly violated in the crudest way; they were exterminated, deprived of their land and resettled in areas unsuitable for life. Now times have changed, and international law recognizes the right of indigenous peoples to restore historical justice and protect their traditional way of life. The paper analyzes the main international documents on the protection of the rights of indigenous peoples, the author traces the dynamics of the establishment and development of international standards in this field, which makes it possible to trace the evolution of international law, determine its role in the modern system of protecting the rights of indigenous peoples and assess the potential for the future
