cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Geodesic motion in the space-time of a non-compact boson star
Creators: name: Diemer, Valeria
name: Eilers, Keno
name: Hartmann, Betti
name: Schaffer, Isabell
name: Toma, Catalin
Publisher: name: arXiv
Year: 2013
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We study the geodesic motion of test particles in the space-time of non-compact boson stars. These objects are made of a self-interacting scalar field and -- depending on the scalar field's mass -- can be as dense as neutron stars or even black holes. In contrast to the former these objects do not contain a well-defined surface, while in contrast to the latter the space-time of boson stars is globally regular, can -- however -- only be given numerically. Hence, the geodesic equation also has to be studied numerically. We discuss the possible orbits for massive and massless test particles and classify them according to the particle's energy and angular momentum. The space-time of a boson star approaches the Schwarzschild space-time asymptotically, however deviates strongly from it close to the center of the star. As a consequence, we find additional bound orbits of massive test particles close to the center of the star that are not present in the Schwarzschild case. Our results can be used to make predictions about extreme-mass-ratio inspirals (EMRIs) and we hence compare our results to recent observational data of the stars orbiting Sagittarius A* - the radiosource at the center of our own galaxy.
description: 18 pages including 7 figures and 7 Tables; v2: proper time intervals added in plots, minor typos corrected, matches version accepted for publication in Phys. Rev. D
A Transfer Learning Approach to Object Detection Acceleration for Embedded Applications
Creators: name: Vance, Lauren M.
Publisher: name: IUPUI ScholarWorks
Year: 2021
Subjects: deep learning
computer vision
object detection
embedded systems
fpga
transfer learning

description: Indiana University-Purdue University Indianapolis (IUPUI)
description: Deep learning solutions to computer vision tasks have revolutionized many industries in recent years, but embedded systems have too many restrictions to take advantage of current state-of-the-art configurations. Typical embedded processor hardware configurations must meet very low power and memory constraints to maintain small and lightweight packaging, and the architectures of the current best deep learning models are too computationally-intensive for these hardware configurations. Current research shows that convolutional neural networks (CNNs) can be deployed with a few architectural modifications on Field-Programmable Gate Arrays (FPGAs) resulting in minimal loss of accuracy, similar or decreased processing speeds, and lower power consumption when compared to general-purpose Central Processing Units (CPUs) and Graphics Processing Units (GPUs). This research contributes further to these findings with the FPGA implementation of a YOLOv4 object detection model that was developed with the use of transfer learning. The transfer-learned model uses the weights of a model pre-trained on the MS-COCO dataset as a starting point then fine-tunes only the output layers for detection on more specific objects of five classes. The model architecture was then modified slightly for compatibility with the FPGA hardware using techniques such as weight quantization and replacing unsupported activation layer types. The model was deployed on three different hardware setups (CPU, GPU, FPGA) for inference on a test set of 100 images. It was found that the FPGA was able to achieve real-time inference speeds of 33.77 frames-per-second, a speedup of 7.74 frames-per-second when compared to GPU deployment. The model also consumed 96% less power than a GPU configuration with only approximately 4% average loss in accuracy across all 5 classes. The results are even more striking when compared to CPU deployment, with 131.7-times speedup in inference throughput. CPUs have long since been outperformed by GPUs for deep learning applications but are used in most embedded systems. These results further illustrate the advantages of FPGAs for deep learning inference on embedded systems even when transfer learning is used for an efficient end-to-end deployment process. This work advances current state-of-the-art with the implementation of a YOLOv4 object detection model developed with transfer learning for FPGA deployment.
title: Современные разработки АО «КНИИТМУ» по промышленной экологии
Creators: name: ., Е.Г. Афонин – к.х.н., ст. науч. сотрудник, АО «Калужский научно-исследовательский институт телемеханических устройств» E-mail: kniitmu@kaluga.net А.В. Баринов – гл. технолог, АО «Калужский научно-исследовательский институт телемеханических устройств» E-mail: kniitmu@kaluga.net
Publisher: name: Издательство Радиотехника
Year: 2019

description: Постановка проблемы. При производстве печатных плат и в процессах электрохимической и химической обработки по-верхности металлов образуются жидкие отходы, содержащие большое разнообразие токсичных химических веществ.
Цель. Представить обзор научно-технологических разработок АО «КНИИТМУ» по нейтрализации сточных вод, обезвреживанию и переработке отработанных растворов гальванического производства и производства печатных плат.
Результаты. Изобретения АО «КНИИТМУ» позволяют осуществлять эффективное извлечение ценных компонентов (цветных металлов, органических веществ) из отработанных растворов гальванического и химического меднения, гальванического и химического никелирования, гальванического цинкования, анодного оксидирования алюминия, травления печатных плат и др., обезвреживание и утилизацию отработанных растворов хрома(+6), переработку отработанного раствора оксидирования стали, а также получать с низкой себестоимостью товарные химические продукты, используя в качестве сырья жидкие отходы производства покрытий. Оптимальным вариантом осуществления изобретений являются малозатратные технологии переработки отработанных растворов, в которых реагентом для химической обработки жидких отходов производства является другой жидкий отход производства, а использование покупных реагентов не требуется.
Практическая значимость. Разработанные в АО «КНИИТМУ» технологии переработки и утилизации отработанных растворов производства покрытий и печатных плат являются технологически несложными и малозатратными. Они могут использоваться как непосредственно на предприятиях, производящих покрытия металлов и/или печатные платы и на которых отработанные растворы образуются, так и на специализированных предприятиях, перерабатывающих промышленные отходы.
Not Conformally-Einstein Metrics in Conformal Gravity
Creators: name: Liu, Hai-Shan
name: Lu, H.
name: Pope, C. N.
name: Vazquez-Poritz, J.
Publisher: name: arXiv
Year: 2013
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The equations of motion of four-dimensional conformal gravity, whose Lagrangian is the square of the Weyl tensor, require that the Bach tensor $E_{μν}= (\nabla^ρ\nabla^σ+ \ft12 R^{ρσ})C_{μρνσ}$ vanishes. Since $E_{μν}$ is zero for any Einstein metric, and any conformal scaling of such a metric, it follows that large classes of solutions in four-dimensional conformal gravity are simply given by metrics that are conformal to Einstein metrics (including Ricci-flat). In fact it becomes more intriguing to find solutions that are {\it not} conformally Einstein. We obtain five new such vacua, which are homogeneous and have asymptotic generalized Lifshitz anisotropic scaling symmetry. Four of these solutions can be further generalized to metrics that are conformal to classes of pp-waves, with a covariantly-constant null vector. We also obtain large classes of generalized Lifshitz vacua in Einstein-Weyl gravity.
description: 19 pages, references added
Central trajectories
Creators: name: Kreveld, Marc Van
name: Löffler, Maarten
name: Staals, Frank
Publisher: name: Journal of Computational Geometry
Year: 2017

description: $\newcommand{\c}{\mathcal{C}}\newcommand{\R}{\mathbb{R}}$An important task in trajectory analysis is clustering. The results of a clustering are often summarized by a single representative trajectory and an associated size of each cluster. We study the problem of computing a suitable representative of a set of similar trajectories. To this end we define a central trajectory $\c$, which consists of pieces of the input trajectories, switches from one entity to another only if they are within a small distance of each other, and such that at any time $t$, the point $\c(t)$ is as central as possible. We measure centrality in terms of the radius of the smallest disk centered at $\c(t)$ enclosing all entities at time $t$, and discuss how the techniques can be adapted to other measures of centrality. We first study the problem in $\R^1$, where we show that an optimal central trajectory $\c$ representing $n$ trajectories, each consisting of $\tau$ edges, has complexity $\Theta(\tau n^2)$ and can be computed in $O(\tau n^2 \log n)$ time. We then consider trajectories in $\R^d$ with $d\geq 2$, and show that the complexity of $\c$ is at most $O(\tau n^{5/2})$ and can be computed in $O(\tau n^3)$ time.
description: Journal of Computational Geometry, Vol. 8 No. 1 (2017)
title: Asymptotics of a thermal wave in one-dimensional harmonic crystal
Creators: name: Krivtsov, A.M.
name: Podolskaya, E.A.
name: Shubina,  V.Yu.
Publisher: name: Peter the Great St. Petersburg Polytechnic University
Year: 2019

description: An asymptotic representation is obtained at large times for the thermal wavefront
propagating in a one-dimensional harmonic crystal. The propagation of thermal waves from a
localized thermal perturbation and the transition zone between regions with different
temperatures is considered. An explicit solution is given for a number of the simplest forms of
the initial temperature distribution. It is shown that during the wave evolution, the wavefront
smoothes, e.g., for a power-law dependence its degree increases by 1/2.
Constraints on Rindler Hydrodynamics
Creators: name: Meyer, Adiel
name: Oz, Yaron
Publisher: name: arXiv
Year: 2013
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We study uncharged Rindler hydrodynamics at second order in the derivative expansion. The equation of state of the theory is given by a vanishing equilibrium energy density. We derive relations among the transport coefficients by employing two frameworks. First, by the requirement of having an entropy current with a non-negative divergence, second by studying the thermal partition function on stationary backgrounds. The relations derived by these two methods are equivalent. We verify the results by studying explicit examples in flat and curved space-time geometries.
title: Nonlinear elastic properties of rubber-cord shells of revolution
Creators: name: Evdokimov, Alexey
Publisher: name: Peter the Great St. Petersburg Polytechnic University
Year: 2019

description: The article presents the results of the study of nonlinear elastic properties of
rubber-cord shells under static loading. A method for determining nonlinear properties is
proposed. The approximations obtained in this case satisfactorily describe the results of the
experiments
Computing nonsimple polygons of minimum perimeter
Creators: name: Fekete, Sándor P.
name: Haas, Andreas
name: Hemmer, Michael
name: Hoffmann, Michael
name: Kostitsyna, Irina
name: Krupke, Dominik
name: Maurer, Florian
name: Mitchell, Joseph S. B.
name: Schmidt, Arne
name: Schmidt, Christiane
name: Troegel, Julian
Publisher: name: Journal of Computational Geometry
Year: 2017

description: We consider the Minimum Perimeter Polygon Problem (MP3): for a given set V of points in the plane, find a polygon P with holes that has vertex set V , such that the total boundary length is smallest possible. The MP3 can be considered a natural geometric generalization of the Traveling Salesman Problem (TSP), which asks for a simple polygon with minimum perimeter. Just like the TSP, the MP3 occurs naturally in the context of curve reconstruction. Even though the closely related problem of finding a minimum cycle cover is polynomially solvable by matching techniques, we prove how the topological structure of a polygon leads to NP-hardness of the MP3. On the positive side, we provide constant-factor approximation algorithms. In addition to algorithms with theoretical worst-case guarantess, we provide practical methods for computing provably optimal solutions for relatively large instances, based on integer programming. An additional difficulty compared to the TSP is the fact that only a subset of subtour constraints is valid, depending not on combinatorics, but on geometry. We overcome this difficulty by establishing and exploiting geometric properties. This allows us to reliably solve a wide range of benchmark instances with up to 600 vertices within reasonable time on a standard machine. We also show that restricting the set of connections between points to edges of the Delaunay triangulation yields results that are on average within 0.5% of the optimum for large classes of benchmark instances.
description: Journal of Computational Geometry, Vol. 8 No. 1 (2017)
Maximizing the sum of radii of disjoint balls or disks
Creators: name: Eppstein, David
Publisher: name: Journal of Computational Geometry
Year: 2017

description: Finding nonoverlapping balls with given centers in any metric space, maximizing the sum of radii of the balls, can be expressed as a linear program. Its dual linear program expresses the problem of finding a minimum-weight set of cycles (allowing 2-cycles) covering all vertices in a complete geometric graph. For points in a Euclidean space of any finite dimension $d$, with any convex distance function on this space, this graph can be replaced by a sparse subgraph obeying a separator theorem. This graph structure leads to an algorithm for finding the optimum set of balls in time $O(n^{2-1/d})$, improving the $O(n^3)$ time of a naive cycle cover algorithm. As a subroutine, we provide an algorithm for weighted bipartite matching in graphs with separators, which speeds up the best previous algorithm for this problem on planar bipartite graphs from $O(n^{3/2}\log n)$ to $O(n^{3/2})$ time.
description: Journal of Computational Geometry, Vol. 8 No. 1 (2017)
Fluctuation-stabilized marginal networks and anomalous entropic elasticity
Creators: name: Dennison, Matthew
name: Sheinman, Michael
name: Storm, Cornelis
name: MacKintosh, Fred C.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: We study the elastic properties of thermal networks of Hookean springs. In the purely mechanical limit, such systems are known to have vanishing rigidity when their connectivity falls below a critical, isostatic value. In this work we show that thermal networks exhibit a non-zero shear modulus $G$ well below the isostatic point, and that this modulus exhibits an anomalous, sublinear dependence on temperature $T$. At the isostatic point, $G$ increases as the square-root of $T$, while we find $G \propto T^α$ below the isostatic point, where $α \simeq 0.8$. We show that this anomalous $T$ dependence is entropic in origin.
description: 9 pages, 7 figures
TESS Experiments: A Conditional Commitment? Partisan Identity and Support for Democracy in the United States
Creators: name: Graham, Matthew H.
name: Huber, Gregory
Publisher: name: Roper Center for Public Opinion Research
Year: 2023

description: Time-sharing Experiments for the Social Sciences (TESS) offers researchers the opportunity to capture the internal validity of experiments. Investigators submit proposals, and TESS fields successful proposals for free on a representative sample of adults in the United States. This experiment was conducted to test the effects of partisanship on Americans’ support for undemocratic behavior. Respondents were randomly assigned to one of two pairs of writing tasks. The treatment tasks asked what makes the respondent similar to their preferred political party and different from the other political party. The control tasks asked what makes the respondent similar to people who enjoy their favorite activity and different from people who enjoy their least favorite activity. All respondents were then asked to complete three candidate choice tasks based on U.S. House candidate profiles. These profiles randomized racial/ethnic and gender cue names (Black female, Black male, Hispanic female, Hispanic male, race/ethnicity neutral female, race/ethnicity neutral male), partisanship (Democrat or Republican), age ( integers 35 to 65), profession (army, farmer, police officer, teacher, small business owner, business executive, doctor, lawyer, political staffer, or prosecutor), marital/family status (married with 0 to 4 children, unmarried with 0 to 2 children), policy positions (one of 10 support possibilities across tax, immigration, healthcare costs, anti-trusts, infrastructure, federal budget, term limit, and education issues) and democracy position (a statement or action violating democratic principles or a proposed an action to uphold democratic principles). A total of 4,027 respondents participated. Respondents also answered metrics of partisan identity strength. This allowed for comparison of respondents’ willingness to trade off democratic principles for partisan interests across candidate profiles and respondent partisan identity.
Injection Current Modulated Parity-Time Symmetry in Coupled Semiconductor Lasers
Creators: name: Thomas, Luke
Publisher: name: IUPUI ScholarWorks
Year: 2021

description: Indiana University-Purdue University Indianapolis (IUPUI)
description: This research investigates the characteristics of Parity Time symmetry breaking in two optically coupled, time delayed semiconductor lasers. A theoretical model is used to describe the controllable parameters in the experiment and intensity output of the coupled lasers. The PT parameters we control are the spatial separation between the two lasers, the frequency detuning, and the coupling strength. We find that the experimental data agrees with the predictions from the theoretical model confirming the intensity behaviors of the lasers, and the monotonic change in PT-threshold as a function of coupling scaled by the time delay
How many three-dimensional Hilbert curves are there?
Creators: name: Haverkort, Herman
Publisher: name: Journal of Computational Geometry
Year: 2017

description: Hilbert's two-dimensional space-filling curve is appreciated for its good locality-preserving properties and easy implementation for many applications. However, Hilbert did not describe how to generalize his construction to higher dimensions. In fact, the number of ways in which this may be done ranges from zero to infinite, depending on what properties of the Hilbert curve one considers to be essential. In this work we take the point of view that a Hilbert curve should at least be self-similar and traverse cubes octant by octant. We organize and explore the space of possible three-dimensional Hilbert curves and the potentially useful properties which they may have. We discuss a notation system that allows us to distinguish the curves from one another and enumerate them. This system has been implemented in a software prototype, available from the author's website. Several examples of possible three-dimensional Hilbert curves are presented, including a curve that visits the points on most sides of the unit cube in the order of the two-dimensional Hilbert curve; curves of which not only the eight octants are similar to each other, but also the four quarters; a curve with excellent locality-preserving properties and endpoints that are not vertices of the cube; a curve in which all but two octants are each other's images with respect to reflections in axis-parallel planes; and curves that can be sketched on a grid without using vertical line segments. In addition, we discuss several four-dimensional Hilbert curves.
description: Journal of Computational Geometry, Vol. 8 No. 1 (2017)
Reducing theoretical uncertainties for exclusive Higgs plus one-jet production at the LHC
Creators: name: Liu, Xiaohui
name: Petriello, Frank
Publisher: name: arXiv
Year: 2013
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We resum a class of large Sudakov logarithms affecting Higgs boson production in the exclusive one-jet bin at the LHC. We extend previous results by calculating the full one-loop soft function for this process, which extends the accuracy of the resummation to include the leading three logarithmic corrections at each order in the QCD coupling constant. We match this result to the next-to-leading order cross section and present a detailed numerical study assuming realistic LHC cuts. Careful attention is paid to the matching procedure, and to the theoretical uncertainties induced by residual scale variation. We find that the matched NLL'+ NLO cross section has significantly smaller uncertainties than the fixed-order result, and can be used to alleviate the theoretical errors hindering current Higgs analyses at the LHC.
description: 25 pages, 5 figures and 1 table. new version with updated discussions on non-global logs, references updated
Neutron matter from chiral effective field theory interactions
Creators: name: Krüger, T.
name: Tews, I.
name: Hebeler, K.
name: Schwenk, A.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Nuclear Theory (nucl-th)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: The neutron-matter equation of state constrains the properties of many physical systems over a wide density range and can be studied systematically using chiral effective field theory (EFT). In chiral EFT, all many-body forces among neutrons are predicted to next-to-next-to-next-to-leading order (N3LO). We present details and additional results of the first complete N3LO calculation of the neutron-matter energy, which includes the subleading three-nucleon as well as the leading four-nucleon forces, and provides theoretical uncertainties. In addition, we discuss the impact of our results for astrophysics: for the supernova equation of state, the symmetry energy and its density derivative, and for the structure of neutron stars. Finally, we give a first estimate for the size of the N3LO many-body contributions to the energy of symmetric nuclear matter, which shows that their inclusion will be important in nuclear structure calculations.
description: published version; 21 pages, 11 figures, 5 tables
The planar tree packing theorem
Creators: name: Geyer, Markus
name: Hoffmann, Michael
name: Kaufmann, Michael
name: Kusters, Vincent
name: Tóth, Csaba D
Publisher: name: Journal of Computational Geometry
Year: 2017

description: Packing graphs is a combinatorial problem where several given graphs are being mapped into a common host graph such that every edge is used at most once. In the planar tree packing problem we are given two trees $T_1$ and $T_2$ on $n$ vertices and have to find a planar graph on $n$ vertices that is the edge-disjoint union of $T_1$ and $T_2$. A clear exception that must be made is the star which cannot be packed together with any other tree. But according to a conjecture of García et al. from 1997 this is the only exception, and all other pairs of trees admit a planar packing. Previous results addressed various special cases, such as a tree and a spider tree, a tree and a caterpillar, two trees of diameter four, two isomorphic trees, and trees of maximum degree three. Here we settle the conjecture in the affirmative and prove its general form, thus making it the planar tree packing theorem. The proof is constructive and provides a polynomial time algorithm to obtain a packing for two given nonstar trees.
description: Journal of Computational Geometry, Vol. 8 No. 2 (2017): Special Issue of Selected Papers from SoCG 2016
title: Формирование функциональных структур на основе гомогенных единиц модульной автономной реконфигурируемой системы
Creators: name: ., Н.А. Павлюк – науч. сотрудник, лаборатория автономных робототехнических систем, Санкт-Петербургский институт информатики и автоматизации РАН E-mail: antei.hasgard@gmail.com П.А. Смирнов – мл. науч. сотрудник, лаборатория автономных робототехнических систем, Санкт-Петербургский институт информатики и автоматизации РАН E-mail: petruha.smirnov.1994@gmail.com А.Д. Ковалев – мл. науч. сотрудник, лаборатория автономных робототехнических систем, Санкт-Петербургский институт информатики и автоматизации РАН E-mail: artem.kovalev1992@gmail.com
Publisher: name: Издательство Радиотехника
Year: 2019

description: Постановка проблемы. Модульная робототехника решает задачи формирования структур, состоящих из гомогенных или гетерогенных робототехнических единиц, совместно работающих в одной цепочке, для получения формаций различных конфигураций и размеров. Проблема самостоятельного передвижения отдельных роботов при организации их взаимодействия и проблема соединения модульных роботов в единую систему – комплексные и взаимосвязанные задачи, для решения которых требуется разработка специализированного аппаратного и программного обеспечения.
Цель. Изучить принципы и возможности компоновки функциональных модульных структур из гомогенных единиц и разработать робототехническую систему, использующую модульные робототехнические устройства (МРУ) мобильной автономной ре-конфигурируемой системы (МАРС) для получения формаций TriMod, Snake и HeadCrab.
Результаты. Предложены конструктивные решения МАРС: двухосного актуатора, колесной базы с основой из всенаправленных колес и захватно-соединительного механизма.
Практическая значимость. Полученные в ходе работы результаты позволяют объединять готовые робототехнические решения, увеличивая грузоподъемность МРУ, рассчитанных на работу в связке с другими устройствами. Предложенные конструктивные решения позволяют вывести вычислительный управляющий отсек в отдельное подключаемое устройство со стандартным набором интерфейсов связи, питания и коммутации, что даст возможность использовать вычислительный блок отдельно и варьировать вычислительную мощность системы по необходимости.
title: Подход к инструментальной оценке цифрового потока сжатых видеоданных, формируемого видеокодеками
Creators: name: ., С.В. Кулешов – д.т.н., гл. науч. сотрудник, зам. директора по научной работе, Санкт-Петербургский институт информатики и автоматизации РАН E-mail: kuleshov@iias.spb.su А.А. Зайцева – к.т.н., ст. науч. сотрудник, лаборатория автоматизации научных исследований, Санкт-Петербургский институт информатики и автоматизации РАН E-mail: cher@iias.spb.su
Publisher: name: Издательство Радиотехника
Year: 2019

description: Постановка проблемы. При оценке и сравнении средств сжатия видеоданных как по объективным, так и по субъективным критериям в основном отсутствует оценка кодеков с точки зрения восприятия человеком, а также с точки зрения экологичности видеоинформации. Основная проблема в измерении субъективных параметров – отсутствие инструментария, используя который, можно доказательно оценить такие параметры, как, например, величина экологического риска, который будет определяться уровнем шумов компрессии и параметрами GOP-структуры, от которых зависят характерные частоты возникающих периодических колебаний.
Цель. Предложить подход к инструментальной оценке цифрового потока сжатых видеоданных, формируемого видеокодеками, с целью инструментального измерения субъективных характеристик их работы и оценки экологичности различных кодеков на основе анализа внутренней структуры данных, сформированной кодером при сжатии видео.
Результаты. Предложенный подход визуализации структуры видеопотока на основе временного анализа работы видеокодека позволяет представить в форме структурных блоков содержимое формируемого им битового потока и обеспечивает инструментальную оценку субъективных параметров, связанных с восприятием изображения, подвергшегося сжатию с потерями. В результате проверки кодеков с применением разработанных программных средств показана актуальность проблемы экологической безопасности видеоданных, связанной с появлением в шумах компрессии периодических компонентов на частотах, попадающих в диапазон частот ритмов мозга человека, особенно для кодеков, используемых в цифровом телевизионном вещании.
Практическая значимость. Разработанный инструментарий позволяет оценивать экологичность различных кодеков, а также давать рекомендации по выбору конфигурации и настройке кодеков для конкретных задач.
Thermal Stability and Electrical Control of Magnetization of Heusler/Oxide Interface and Non-collinear Spin Transport of Its Junction
Creators: name: Bai, Zhaoqiang
name: Shen, Lei
name: Cai, Yongqing
name: Wu, Qingyun
name: Zeng, Minggang
name: Han, Guchang
name: Feng, Yuan Ping
Publisher: name: arXiv
Year: 2013
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Towards next-generation spintronics devices, such as computer memories and logic chips, it is necessary to satisfy high thermal stability, low-power consumption and high spin-polarization simultaneously. Here, from first-principles, we investigate thermal stability (both structure and magnetization) and the electric field control of magnetic anisotropy on Co2FeAl (CFA)/MgO. A phase diagram of structural thermal stability of the CFA/MgO interface is illustrated. An interfacial perpendicular-anisotropy, coming from the Fe-O orbital hybridization, provides high magnetic thermal stability and a low stray field. We find an electric-field-induced giant modification of such perpendicular-anisotropy via a great magnetoelectric effect (the anisotropy energy coefficient beta~10-7 erg/V cm). Our spin electronic-structure and non-collinear transport calculations indicate high spin-polarized interfacial states and good magnetoresistance properties of CFA/MgO/CFA perpendicular magnetic tunnel junctions.
description: 6 pages, 5 figures, 1 table. arXiv admin note: text overlap with arXiv:0903.2228 by other authors
Spinmotive force with static and uniform magnetization induced by a time-varying electric field
Creators: name: Yamane, Yuta
name: Ieda, Jun'ichi
name: Maekawa, Sadamichi
Publisher: name: arXiv
Year: 2013
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: A new spinmotive force is predicted in ferromagnets with spin-orbit coupling. By extending the theory of spinmotive force, we show that a time-varying electric field can induce a spinmotive force with static and uniform magnetization. This spinmotive has two advantages; it can be detected free from the inductive voltage owing to the absence of dynamical magnetization and it can be tuned by electric fields. To observe the effect, we propose two experimental setups: electric voltage measurement in a single ferromagnet and spin injection from a ferromagnet into an attached nonmagnetic conductor.
title: Кластеризация пикселей иерархически структурированного изображения
Creators: name: ., М.В. Харинов – к.т.н., доцент, ст. науч. сотрудник, лаборатория технологий больших данных киберфизических систем, Санкт-Петербургский институт информатики и автоматизации РАН E-mail: khar@iias.spb.su
Publisher: name: Издательство Радиотехника
Year: 2019

description: Постановка проблемы. Насущной проблемой компьютерной обработки изображений является детектирование объектов, которое обычно опирается на априорную информацию об объектах и обрабатываемых изображениях. Проблема возникает в решениях, не учитывающих того, что исходное изображение отображает иерархию объектов различной величины и поэтому является неоднозначным. Используемые для адекватного детектирования объектов классические методы кластеризации пикселей с численной оценкой качества обработки также не учитывают иерархическую природу изображения, что снижает их эффективность в силу недостаточного объема входных данных.
Цель. Построить модель иерархического представления объектов на изображении и эквивалентную сетевую модель вычислений, позволяющую работать с миллионами множеств пикселей так же просто, как с миллионами пикселей при быстродействии и ресурсах памяти обычного современного компьютера, в которой, в отличие от традиционных многослойных нейронных сетей, слои «нейронов» образуют циклические и ациклические графы (деревья).
Результаты. Для адекватного детектирования объектов решается задача оптимизации приближений изображения по суммарной квадратичной ошибке (ошибке аппроксимации). Эффективная минимизация ошибки аппроксимации и исключение использования априорной информации об объектах обеспечивается благодаря аппроксимации изображения иерархией приближений, предназначенной для отображения иерархии объектов на изображении. В приложении к иерархически структурированному изображению раскрываются возможности классических методов кластерного анализа. Предлагаются принципы скоростных вычислений в терминах алгебраической сети, которая разделяется на циклические и ациклические графы (деревья) и формируется посредством обратимого объединения элементарных графов.
Практическая значимость. Формальная наглядная и эквивалентная вычислительная модель иерархического представления объектов на изображении необходима для создания унифицированного инструментария предварительной обработки изображения, который помогает инженеру-программисту справляться с детектированием объектов при решении многочисленных практических задач.
AI on the Edge with CondenseNeXt: An Efficient Deep Neural Network for Devices with Constrained Computational Resources
Creators: name: Kalgaonkar, Priyank B.
Publisher: name: IUPUI ScholarWorks
Year: 2021
Subjects: CondenseNeXt
edge
efficient
model
CIFAR10
CIFAR100
Python
PyTorch
Priyank Kalgaonkar
Image Processing
Computer Vision
Deep Learning
Neural Networks
AI
Image Classification
Machine Learning
Artificial Intelligence
CondenseNet
algorithm
CNN
DNN
ANN
NN
edge computing

description: Indiana University-Purdue University Indianapolis (IUPUI)
description: Research work presented within this thesis propose a neoteric variant of deep convolutional neural network architecture, CondenseNeXt, designed specifically for ARM-based embedded computing platforms with constrained computational resources. CondenseNeXt is an improved version of CondenseNet, the baseline architecture whose roots can be traced back to ResNet. CondeseNeXt replaces group convolutions in CondenseNet with depthwise separable convolutions and introduces group-wise pruning, a model compression technique, to prune (remove) redundant and insignificant elements that either are irrelevant or do not affect performance of the network upon disposition. Cardinality, a new dimension to the existing spatial dimensions, and class-balanced focal loss function, a weighting factor inversely proportional to the number of samples, has been incorporated in order to relieve the harsh effects of pruning, into the design of CondenseNeXt’s algorithm. Furthermore, extensive analyses of this novel CNN architecture was performed on three benchmarking image datasets: CIFAR-10, CIFAR-100 and ImageNet by deploying the trained weight on to an ARM-based embedded computing platform: NXP BlueBox 2.0, for real-time image classification. The outputs are observed in real-time in RTMaps Remote Studio’s console to verify the correctness of classes being predicted. CondenseNeXt achieves state-of-the-art image classification performance on three benchmark datasets including CIFAR-10 (4.79% top-1 error), CIFAR-100 (21.98% top-1 error) and ImageNet (7.91% single model, single crop top-5 error), and up to 59.98% reduction in forward FLOPs compared to CondenseNet. CondenseNeXt can also achieve a final trained model size of 2.9 MB, however at the cost of 2.26% in accuracy loss. Thus, performing image classification on ARM-Based computing platforms without requiring a CUDA enabled GPU support, with outstanding efficiency.
Classifying unavoidable Tverberg partitions
Creators: name: Bukh, Boris
name: Loh, Po-Shen
name: Nivasch, Gabriel
Publisher: name: Journal of Computational Geometry
Year: 2017

description: Let $T(d,r) = (r-1)(d+1)+1$ be the parameter in Tverberg's theorem, and call a partition $\mathcal I$ of $\{1,2,\ldots,T(d,r)\}$ into $r$ parts a Tverberg type. We say that $\mathcal I$ occurs in an ordered point sequence $P$ if $P$ contains a subsequence $P'$ of $T(d,r)$ points such that the partition of $P'$ that is order-isomorphic to $\mathcal I$ is a Tverberg partition. We say that $\mathcal I$ is unavoidable if it occurs in every sufficiently long point sequence. In this paper we study the problem of determining which Tverberg types are unavoidable. We conjecture a complete characterization of the unavoidable Tverberg types, and we prove some cases of our conjecture for $d\le 4$. Along the way, we study the avoidability of many other geometric predicates. Our techniques also yield a large family of $T(d,r)$-point sets for which the number of Tverberg partitions is exactly $(r-1)!^d$. This lends further support for Sierksma's conjecture on the number of Tverberg partitions.
description: Journal of Computational Geometry, Vol. 8 No. 1 (2017)
title: Генерация пользовательского интерфейса на основе технологии распределенной виртуальной среды
Creators: name: ., И.О. Шальнев – аспирант, программист, лаборатория автоматизации научных исследований, Санкт-Петербургский институт информатики и автоматизации РАН E-mail: elias.shalnev@gmail.com А.Ю. Аксенов – к.т.н., ст. науч. сотрудник, лаборатория автоматизации научных исследований, Санкт-Петербургский институт информатики и автоматизации РАН E-mail: a_aksenov@iias.spb.su
Publisher: name: Издательство Радиотехника
Year: 2019

description: Постановка проблемы. Развитие современных информационных систем определяется насущными требованиями общества и рынка. Увеличивающиеся объемы обрабатываемой информации, необходимость постоянного доступа к информационным системам, возникающая реальность автономных систем обостряет проблему взаимодействия компонентов сети и их взаимной интеграции. Каждый человек фактически постоянно включен в пространство личных и корпоративных информационных взаимодействий, непосредственно принимает участие в формировании информационных потоков и управленческих сигналов, взаимодействует с другими участниками системы. Огромное число информационных систем создает препятствие для единовременного и комфортного их использования, не говоря уже о том, что все системы не уместить в одном устройстве. В качестве решения еще в 1960-х годах был предложен терминальный подход в качестве устройства доступа к информационной системе.
Цель. Разработать новый подход к реализации приложений с терминалом для решения проблемы, поставленной современным цифровым пространством.
Результаты. Генерация пользовательского интерфейса на основе использования технологии распределенной виртуальной среды, на взгляд авторов, показала свою эффективность как на концептуальном уровне, так и в производительности. Интерпретация управляющих команд виртуальной машины оказалось эффективней процессинга текстового формата HTML, что делает такой подход конкурентоспособным. В предложенном подходе пользовательский интерфейс генерируется динамически на основании работы сервиса приложения, находящегося на другом сетевом узле. Таким образом, пользователь имеет единую точку входа к массиву информационных систем.
Практическая значимость. Предлагаемый подход найдет свое применение во многих инфокоммуникационных мобильных системах, особенно в системах, использующих для своего реконфигурирования технологию активных данных.
A new drawing for simple Venn diagrams based on algebraic construction
Creators: name: Bannier, Arnaud
name: Bodin, Nicolas
Publisher: name: Journal of Computational Geometry
Year: 2017

description: Venn diagrams are used to display all relations between a finite number of sets. Recent researches in this domain concern the mathematical aspects of these constructions, but are not directed towards the readability of the diagram. This article presents a new way to draw easy-to-read Venn diagrams, in which each region tends to be drawn with the same size when the number of sets grows, and tends to draw a grid. Finally, using linear algebra, we prove that this construction gives a simple Venn diagram for any number of sets.
description: Journal of Computational Geometry, Vol. 8 No. 1 (2017)
A Cyclic Douglas-Rachford Iteration Scheme
Creators: name: Borwein, Jonathan M.
name: Tam, Matthew K.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Optimization and Control (math.OC)
subject: Functional Analysis (math.FA)
subject: FOS: Mathematics

description: In this paper we present two Douglas-Rachford inspired iteration schemes which can be applied directly to N-set convex feasibility problems in Hilbert space. Our main results are weak convergence of the methods to a point whose nearest point projections onto each of the N sets coincide. For affine subspaces, convergence is in norm. Initial results from numerical experiments, comparing our methods to the classical (product-space) Douglas-Rachford scheme, are promising.
description: 22 pages, 7 figures, 4 tables
Large Scale Structure Constraints for a Class of f(R) Theories of Gravity
Creators: name: Abebe, Amare
name: Dombriz, Alvaro de la Cruz
name: Dunsby, Peter K. S.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Over the last few years much attention has been given to the study of modified gravity theories in order to find a more natural explanation for the late time acceleration of the Universe. Nevertheless, a comparison of the matter power spectrum predictions made by these theories with available data has not yet been subjected to a detailed analysis. In the context of f(R) theories of gravity we study the predicted power spectra using both a dynamical systems approach for the background and solving for the matter perturbations without using the quasi-static approximation, comparing the theoretical results with several SDSS data. The importance of studying the first order perturbed equations by assuming the correct background evolution and the relevance of the initial conditions are also stressed. We determine the statistical significance in relation to the observational data and demonstrate their conflict with existing observations.
description: 12 pages, 2 figures, BAO and SDSS DR9 CMASS (SDSS-III BOSS 2012) analyses implemented. Conclusions extended
title: Development of numerical methods and virtual tests for cyclic durability by finite element method
Creators: name: Papirovskiy, A.
name: Alekseev, S.
name: Tarasov, A.
name: Borovkov, A.
Publisher: name: Peter the Great St. Petersburg Polytechnic University
Year: 2019

description: This paper deals with the issue of fatigue failure of materials. The process of
generation of fatigue properties for the steel 08PS is described and obtained in the laboratory.
The technique of conducting virtual tests for cyclic durability for vehicles is proposed. Virtual
tests for cyclic durability by using the finite element method on the example of an off-road car
body are performed.
Competitive local routing with constraints
Creators: name: Bose, Prosenjit
name: Fagerberg, Rolf
name: Van Renssen, André
name: Verdonschot, Sander
Publisher: name: Journal of Computational Geometry
Year: 2017

description: Let $P$ be a set of $n$ vertices in the plane and $S$ a set of non-crossing line segments between vertices in $P$, called constraints. Two vertices are visible if the straight line segment connecting them does not properly intersect any constraints. The constrained $\Theta_m$-graph is constructed by partitioning the plane around each vertex into $m$ disjoint cones, each with aperture $\theta = 2 \pi/m$, and adding an edge to the `closest' visible vertex in each cone. We consider how to route on the constrained $\Theta_6$-graph. We first show that no deterministic 1-local routing algorithm is $o(\sqrt{n})$-competitive on all pairs of vertices of the constrained $\Theta_6$-graph. After that, we show how to route between any two visible vertices of the constrained $\Theta_6$-graph using only 1-local information. Our routing algorithm guarantees that the returned path has length at most 2 times the Euclidean distance between the source and destination. Additionally, we provide a 1-local 18-competitive routing algorithm for visible vertices in the constrained half-$\Theta_6$-graph, a subgraph of the constrained $\Theta_6$-graph that is equivalent to the Delaunay graph where the empty region is an equilateral triangle. To the best of our knowledge, these are the first local routing algorithms in the constrained setting with guarantees on the length of the returned path.
description: Journal of Computational Geometry, Vol. 8 No. 1 (2017)
Learning-based Attack and Defense on Recommender Systems
Creators: name: Palanisamy Sundar, Agnideven
Publisher: name: IUPUI ScholarWorks
Year: 2021
Subjects: Recommender Systems
Machine Learning
Deep Learning
Reinforcement Learning
Fraud Detection
Fake Reviews
Shilling Attacks
Graph Embedding
Multi-Armed Bandits

description: Indiana University-Purdue University Indianapolis (IUPUI)
description: The internet is the home for massive volumes of valuable data constantly being created, making it difficult for users to find information relevant to them. In recent times, online users have been relying on the recommendations made by websites to narrow down the options. Online reviews have also become an increasingly important factor in the final choice of a customer. Unfortunately, attackers have found ways to manipulate both reviews and recommendations to mislead users. A Recommendation System is a special type of information filtering system adapted by online vendors to provide suggestions to their customers based on their requirements. Collaborative filtering is one of the most widely used recommendation systems; unfortunately, it is prone to shilling/profile injection attacks. Such attacks alter the recommendation process to promote or demote a particular product. On the other hand, many spammers write deceptive reviews to change the credibility of a product/service. This work aims to address these issues by treating the review manipulation and shilling attack scenarios independently. For the shilling attacks, we build an efficient Reinforcement Learning-based shilling attack method. This method reduces the uncertainty associated with the item selection process and finds the most optimal items to enhance attack reach while treating the recommender system as a black box. Such practical online attacks open new avenues for research in building more robust recommender systems. When it comes to review manipulations, we introduce a method to use a deep structure embedding approach that preserves highly nonlinear structural information and the dynamic aspects of user reviews to identify and cluster the spam users. It is worth mentioning that, in the experiment with real datasets, our method captures about 92\% of all spam reviewers using an unsupervised learning approach.