69 research outputs found
The chaotic dynamics of comets and the problems of the Oort cloud
The dynamic properties of comets entering the planetary zone from the Oort cloud are discussed. Even a very slight influence of the large planets can trigger stochastic cometary dynamics. Multiple interactions of comets with the large planets produce diffusion of the parameters of cometary orbits and a mean increase in the semi-major axis of comets. Comets are lifted towards the Oort cloud, where collisions with stars begin to play a substantial role. The transport of comets differs greatly from the customary law of diffusion and noticeably alter cometary distribution
Many-to-Many Graph Matching: a Continuous Relaxation Approach
Graphs provide an efficient tool for object representation in various
computer vision applications. Once graph-based representations are constructed,
an important question is how to compare graphs. This problem is often
formulated as a graph matching problem where one seeks a mapping between
vertices of two graphs which optimally aligns their structure. In the classical
formulation of graph matching, only one-to-one correspondences between vertices
are considered. However, in many applications, graphs cannot be matched
perfectly and it is more interesting to consider many-to-many correspondences
where clusters of vertices in one graph are matched to clusters of vertices in
the other graph. In this paper, we formulate the many-to-many graph matching
problem as a discrete optimization problem and propose an approximate algorithm
based on a continuous relaxation of the combinatorial problem. We compare our
method with other existing methods on several benchmark computer vision
datasets.Comment: 1
PLATFORM ARCHITECTURE FOR DEVELOPMENT OF MOBILE APPLICATIONS WITH OUTDOOR-QUESTS
Subject of Research. The paper presents the review of existing platforms for development of mobile applications with outdoor-quests. A method for automation design and planning of outdoor-quests is proposed. The principles for development automation of mobile applications containing such quests are described. Method. The novelty of the proposed approach lies in procedural quest generation based on a set of limitations. The architecture combines the usage of open technologies with quests generation and includes special tools for automated creation of outdoor quest templates on various subjectsas well as customizable application templates. Main Results. Experimental research was carried out for evaluation of the proposed architecture features. By implementing quest generator and application templates a demo Android application was created. The application consisted of two quests: manually created and generated one. The generated quest was made by quest generator and extended by human. The application was published at Play Market Store. The experiment goal was to measure how long will it take for application users to find different quest object and how long will it take to pass the quest all over in order to determine the differences in generated and manually created quests. As a result of comparative measurements a conclusion was made about allowable difference between quests because it was less than attention cycle duration for humans. This fact demonstrates that generated quests can be used in the same manner as manually created ones. Practical Relevance. The proposed quest generator can be used for wide range of topics because quest object selection is based on keyword search and quest route geometry criterion application. The solution also has practical significance because mobile applications developed with the use of the proposed architecture can be adapted to different domain areas. Wherein mobile application development time is reduced owing to automation and customizable templates usage
Global alignment of protein-protein interaction networks by graph matching methods
Aligning protein-protein interaction (PPI) networks of different species has
drawn a considerable interest recently. This problem is important to
investigate evolutionary conserved pathways or protein complexes across
species, and to help in the identification of functional orthologs through the
detection of conserved interactions. It is however a difficult combinatorial
problem, for which only heuristic methods have been proposed so far. We
reformulate the PPI alignment as a graph matching problem, and investigate how
state-of-the-art graph matching algorithms can be used for that purpose. We
differentiate between two alignment problems, depending on whether strict
constraints on protein matches are given, based on sequence similarity, or
whether the goal is instead to find an optimal compromise between sequence
similarity and interaction conservation in the alignment. We propose new
methods for both cases, and assess their performance on the alignment of the
yeast and fly PPI networks. The new methods consistently outperform
state-of-the-art algorithms, retrieving in particular 78% more conserved
interactions than IsoRank for a given level of sequence similarity.
Availability:http://cbio.ensmp.fr/proj/graphm\_ppi/, additional data and codes
are available upon request. Contact: [email protected]: Preprint versio
Разработка системы экологического мониторинга на базе технологий пространственной разметки и машинного зрения
Introduction. The use of available satellite images and aerial photography by unmanned aerial vehicles (UAVs) in the tasks of environmental monitoring is challenged by the imperfection of existing tools. Geographic information systems are characterized by insufficient flexibility to automatically work with heterogeneous sources. The latest models based on artificial intelligence in ecology require preliminary data preparation. The article presents the results of designing a software system for environmental monitoring based on machine vision sensor data, which provides data unification while being flexible both in terms of data sources and methods of their analysis.Aim. Creation of a generalized software system for coordinated spatial marking of heterogeneous machine vision data for environmental monitoring tasks.Materials and methods. Software engineering methods, database theory methods, spatial markup methods, image processing methods.Results. A generalized method for unifying data was developed. The method is based on the analysis of existing open data from remote sensing of the Earth, as well as UAV aerial photography and approaches to environmental monitoring. To implement the method, a flexible architecture of the software system was designed, and a data model for a document-oriented DBMS was developed, which allows storing data and scaling the data analysis procedure.Conclusion. The existing sources of data and tools for environmental monitoring were analyzed. A generalized method for unifying machine vision data, an architecture, and a data model was created. The method, architecture, and model were successfully implemented as a software system with a web interfaceВведение. Использование доступных спутниковых снимков и аэрофотосъемки беспилотными летательными аппаратами (БПЛА) в задачах экологического мониторинга наталкивается на несовершенство существующих инструментов. Геоинформационные системы не обладают достаточной гибкостью для автоматической работы с гетерогенными источниками, а новейшие модели искусственного интеллекта в экологии требуют предварительной подготовки данных. В статье представлены результаты проектирования программной системы экологического мониторинга по данным сенсоров машинного зрения, которая обеспечивает унификацию данных и одновременно является гибкой как с точки зрения источников данных, так и способов их анализа.Цель работы. Создание открытой программной системы для согласованной пространственной разметки гетерогенных данных машинного зрения для задач экологического мониторинга.Материалы и методы. Методы программной инженерии, методы теории баз данных, методы пространственной разметки, методы обработки изображений.Результаты. На основе анализа особенностей существующих открытых данных дистанционного зондирования Земли, а также аэрофотосъемки БПЛА и подходов к проведению экологического мониторинга составлен обобщенный метод унификации данных. Для реализации метода была составлена гибкая архитектура программной системы, а также разработана модель данных для документоориентированной системы управления базами данных, позволяющие хранить данные и масштабировать процедуру анализа данных.Заключение. В статье проведен анализ существующих источников данных и инструментов проведения экологического мониторинга. Создан обобщенный метод унификации данных машинного зрения, архитектура и модель данных. Метод, архитектура и модель успешно реализованы в виде программной системы с веб-интерфейсо
Effectiveness of immunobloting method in syphilis differential diagnostics in pregnancy
168 pregnant women suspected to be infected with syphilis were observed within this research. To prove the presence of antibody in whey blood to antigenes Treponema pallidum we used sets recomBlot Treponema IgM and recomBlot Treponema IgG («Microgen», Germany). In immunological observations the following indexes were included defining number of lymphocyte subpopulations (CD3+ -, CD4+ -, CD8+ -, CD16+ – , CD19+ и CD25+ – lymphocyte) and level in blood serum Interleukin-1β, Interleukin-2, Interleukin-4, Interleukin-8 и INF-γ. Treponema tests in 100% of cases showed positive results, regardless of patients’ category. An examination of pregnant women with serum resistance the immunobloting sensitivity for detecting IgG-antibodies was 61,6%. In 38,4% of cases bloting showed uncertain results, because it detected antibodies to only one or two out of 5 treponemnyh antigens. Level of INF-γ for pregnant women with serum resistance increases, this reflects predominance of immune regulation of Th-1 type. Based on the results we offer general scheme of dealing with pregnant patients with suspected syphilis. These results can be used for differential diagnosis of latent syphilis, and serum resistance
Comparing biological networks via graph compression
<p>Abstract</p> <p>Background</p> <p>Comparison of various kinds of biological data is one of the main problems in bioinformatics and systems biology. Data compression methods have been applied to comparison of large sequence data and protein structure data. Since it is still difficult to compare global structures of large biological networks, it is reasonable to try to apply data compression methods to comparison of biological networks. In existing compression methods, the uniqueness of compression results is not guaranteed because there is some ambiguity in selection of overlapping edges.</p> <p>Results</p> <p>This paper proposes novel efficient methods, CompressEdge and CompressVertices, for comparing large biological networks. In the proposed methods, an original network structure is compressed by iteratively contracting identical edges and sets of connected edges. Then, the similarity of two networks is measured by a compression ratio of the concatenated networks. The proposed methods are applied to comparison of metabolic networks of several organisms, <it>H. sapiens, M. musculus, A. thaliana, D. melanogaster, C. elegans, E. coli, S. cerevisiae,</it> and <it>B. subtilis,</it> and are compared with an existing method. These results suggest that our methods can efficiently measure the similarities between metabolic networks.</p> <p>Conclusions</p> <p>Our proposed algorithms, which compress node-labeled networks, are useful for measuring the similarity of large biological networks.</p
An Analysis of Errors in Graph-Based Keypoint Matching and Proposed Solutions
International audienceAn error occurs in graph-based keypoint matching when key-points in two different images are matched by an algorithm but do not correspond to the same physical point. Most previous methods acquire keypoints in a black-box manner, and focus on developing better algorithms to match the provided points. However to study the complete performance of a matching system one has to study errors through the whole matching pipeline, from keypoint detection, candidate selection to graph optimisation. We show that in the full pipeline there are six different types of errors that cause mismatches. We then present a matching framework designed to reduce these errors. We achieve this by adapting keypoint detectors to better suit the needs of graph-based matching, and achieve better graph constraints by exploiting more information from their keypoints. Our framework is applicable in general images and can handle clutter and motion discontinuities. We also propose a method to identify many mismatches a posteriori based on Left-Right Consistency inspired by stereo matching due to the asymmetric way we detect keypoints and define the graph
Simultaneous Optimization of Both Node and Edge Conservation in Network Alignment via WAVE
Network alignment can be used to transfer functional knowledge between
conserved regions of different networks. Typically, existing methods use a node
cost function (NCF) to compute similarity between nodes in different networks
and an alignment strategy (AS) to find high-scoring alignments with respect to
the total NCF over all aligned nodes (or node conservation). But, they then
evaluate quality of their alignments via some other measure that is different
than the node conservation measure used to guide the alignment construction
process. Typically, one measures the amount of conserved edges, but only after
alignments are produced. Hence, a recent attempt aimed to directly maximize the
amount of conserved edges while constructing alignments, which improved
alignment accuracy. Here, we aim to directly maximize both node and edge
conservation during alignment construction to further improve alignment
accuracy. For this, we design a novel measure of edge conservation that (unlike
existing measures that treat each conserved edge the same) weighs each
conserved edge so that edges with highly NCF-similar end nodes are favored. As
a result, we introduce a novel AS, Weighted Alignment VotEr (WAVE), which can
optimize any measures of node and edge conservation, and which can be used with
any NCF or combination of multiple NCFs. Using WAVE on top of established
state-of-the-art NCFs leads to superior alignments compared to the existing
methods that optimize only node conservation or only edge conservation or that
treat each conserved edge the same. And while we evaluate WAVE in the
computational biology domain, it is easily applicable in any domain.Comment: 12 pages, 4 figure
Adaptively Transforming Graph Matching
Recently, many graph matching methods that incorporate pairwise constraint
and that can be formulated as a quadratic assignment problem (QAP) have been
proposed. Although these methods demonstrate promising results for the graph
matching problem, they have high complexity in space or time. In this paper, we
introduce an adaptively transforming graph matching (ATGM) method from the
perspective of functional representation. More precisely, under a
transformation formulation, we aim to match two graphs by minimizing the
discrepancy between the original graph and the transformed graph. With a linear
representation map of the transformation, the pairwise edge attributes of
graphs are explicitly represented by unary node attributes, which enables us to
reduce the space and time complexity significantly. Due to an efficient
Frank-Wolfe method-based optimization strategy, we can handle graphs with
hundreds and thousands of nodes within an acceptable amount of time. Meanwhile,
because transformation map can preserve graph structures, a domain
adaptation-based strategy is proposed to remove the outliers. The experimental
results demonstrate that our proposed method outperforms the state-of-the-art
graph matching algorithms
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