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Статті в журналах з теми "Local Hardy spaces"
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Betancor, Jorge J., and Wendolín Damián. "Anisotropic Local Hardy Spaces." Journal of Fourier Analysis and Applications 16, no. 5 (February 18, 2010): 658–75. http://dx.doi.org/10.1007/s00041-010-9121-x.
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Ding, Wei, and Feng Yu. "Dual Spaces of Multiparameter Local Hardy Spaces." Journal of Function Spaces 2021 (December 3, 2021): 1–12. http://dx.doi.org/10.1155/2021/9619925.
Повний текст джерелаАнотація:
In this paper, we study the duality theory of the multiparameter local Hardy spaces h p ℝ n 1 × ℝ n 2 , and we prove that h p ℝ n 1 × ℝ n 2 ∗ = cm o p ℝ n 1 × ℝ n 2 , where cm o p ℝ n 1 × ℝ n 2 are defined by discrete Carleson measure. Moreover, we discuss the relationship among cm o p ℝ n 1 × ℝ n 2 , Li p p ℝ n 1 × ℝ n 2 , and rectangle cm o rect p ℝ n 1 × ℝ n 2 .
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Xia, Runlian, and Xiao Xiong. "Operator-valued local Hardy spaces." Journal of Operator Theory 82, no. 2 (September 15, 2019): 383–443. http://dx.doi.org/10.7900/jot.2018jun02.2191.
Повний текст джерелаАнотація:
This paper gives a systematic study of operator-valued local\break Hardy spaces, which are localizations of the Hardy spaces defined by Mei. We prove the h1-bmo duality and the hp-hq duality for any conjugate pair (p,q) when p∈(1,∞). We show that h1(Rd,M) and bmo(Rd,M) are also good endpoints of Lp(L∞(Rd)¯¯¯¯⊗M) for interpolation. We obtain the local version of Calder\'on--Zygmund theory, and then deduce that the Poisson kernel in our definition of the local Hardy norms can be replaced by any reasonable test function. Finally, we establish the atomic decomposition of the local Hardy space hc1(Rd,M).
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Ding, Wei, Guozhen Lu, and YuePing Zhu. "Multi-parameter local Hardy spaces." Nonlinear Analysis 184 (July 2019): 352–80. http://dx.doi.org/10.1016/j.na.2019.02.014.
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Tang, Lin. "The weighted weak local Hardy spaces." Rocky Mountain Journal of Mathematics 44, no. 1 (February 2014): 297–315. http://dx.doi.org/10.1216/rmj-2014-44-1-297.
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Hounie, J., and Rafael Augusto dos Santos Kapp. "Pseudodifferential Operators on Local Hardy Spaces." Journal of Fourier Analysis and Applications 15, no. 2 (April 22, 2008): 153–78. http://dx.doi.org/10.1007/s00041-008-9021-5.
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Peloso, Marco M., and Silvia Secco. "Local Riesz transforms characterization of local Hardy spaces." Collectanea mathematica 59, no. 3 (October 2008): 299–320. http://dx.doi.org/10.1007/bf03191189.
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Yang, Dachun. "Local hardy and BMO spaces on non-homogeneous spaces." Journal of the Australian Mathematical Society 79, no. 2 (October 2005): 149–82. http://dx.doi.org/10.1017/s1446788700010430.
Повний текст джерелаАнотація:
AbstractLet µ be Radon measure on Rd which may be non doubling. The only condition that µ must satisfy is the size condition µ(B(x, r)) ≤ Crn for some fixed n є (0, d). Recently, Tolsa introduced the spaces RBMO(µ) and Hatb1.∞ (µ), which, in some ways, play the role of the classical spaces BMO and H1 in case u is a doubling measure. In this paper, the author considers the local versions of the spaces RBMO(µ) and Hatb1.∞ (µ) in the sense of Goldberg and establishes the connections between the spaces RBMO(µ) and Hatb1.∞ (µ) with their local versions. An interpolation result of linear operators is also given.
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Zhou, Guangcai, and Weixing Zheng. "LOCAL HARDY SPACES ON HEISENBERG GROUP OVER LOCAL FIELDS." Acta Mathematica Scientia 16, no. 2 (April 1996): 129–41. http://dx.doi.org/10.1016/s0252-9602(17)30788-9.
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Bloom, Walter R., and Zengfu Xu. "Local Hardy spaces on Chébli-Trimèche hypergroups." Studia Mathematica 133, no. 3 (1999): 197–230. http://dx.doi.org/10.4064/sm-133-3-197-230.
Повний текст джерелаДисертації з теми "Local Hardy spaces"
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Routin, Eddy. "Local Tb theorems and Hardy type inequalities." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00656023.
Повний текст джерелаАнотація:
In this thesis, we study local Tb theorems for singular integral operators in the setting of spaces of homogeneous type. We give a direct proof of the local Tb theorem with L^2 integrability on the pseudo- accretive system. Our argument relies on the Beylkin-Coifman-Rokhlin algorithm applied in adapted Haar wavelet basis and some stopping time results. Motivated by questions of S. Hofmann, we extend it to the case when the integrability conditions are lower than 2, with an additional weak boundedness type hypothesis, which incorporates some Hardy type inequalities. We study the possibility of relaxing the support conditions on the pseudo-accretive system to a slight enlargement of the dyadic cubes. We also give a result in the case when, for practical reasons, hypotheses on the pseudo-accretive system are made on balls rather than dyadic cubes. Finally we study the particular case of perfect dyadic operators for which the proof gets much simpler. Our argument gives us the opportunity to study Hardy type inequalities. The latter are well known in the Euclidean setting, but seem to have been overlooked in spaces of homogeneous type. We prove that they hold without restriction in the dyadic setting. In the more general case of a ball B and its corona 2B\B, they can be obtained from some geometric conditions relative to the distribution of points in the homogeneous space. For example, we prove that some relative layer decay property suffices. We also prove that this property is implied by the monotone geodesic property of Tessera. Finally, we give some explicit examples and counterexamples in the complex plane to illustrate the relationship between the geometry of the homogeneous space and the validity of the Hardy type inequalities.
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Merchan, Spiegel Fernando. "Nouvelles approches de modélisation multidimensionnelle fondées sur la décomposition de Wold." Thesis, Bordeaux 1, 2009. http://www.theses.fr/2009BOR13955/document.
Повний текст джерелаАнотація:
Dans cette thèse nous proposons de nouveaux modèles paramétriques en traitement du signal et de l'image, fondés sur la décomposition de Wold des processus stochastiques. Les approches de modélisation font appel à l'analyse fonctionnelle et harmonique, l'analyse par ondelettes, ainsi qu'à la théorie des champs stochastiques. Le premier chapitre a un caractère introductif théorique et précise les éléments de base concernant le contexte de la prédiction linéaire des processus stochastiques stationnaires et la décomposition Wold, dans le cas 1-D et multi-D. On montre comment les différentes parties de la décomposition sont obtenues à partir de l'hypothèse de stationnarité, via la représentation du processus comme l'orbite d'un certain opérateur unitaire, l'isomorphisme canonique de Kolmogorov et les conséquences sur la prédiction linéaire du théorème de Szégö et de ses extensions multidimensionnelles. Le deuxième chapitre traite une approche de factorisation spectrale de la densité spectrale de puissance qu'on utilisera pour l'identification des modèles de type Moyenne Ajustée (MA), Autorégressif (AR) et ARMA. On utilise la représentation par le noyau reproduisant de Poisson d'une fonction extérieure pour construire un algorithme d'estimation d'un modèle MA avec une densité spectrale de puissance donnée. Cette méthode d'estimation est présentée dans le cadre de deux applications: - Dans la simulation de canaux sans fil de type Rayleigh (cas 1-D). - Dans le cadre d'une approche de décomposition de Wold des images texturées (cas 2-D). Dans le troisième chapitre nous abordons la représentation et la compression hybride d'images. Nous proposons une approche de compression d'images qui utilise conjointement : - les modèles issus de la décomposition de Wold pour la représentation des régions dites texturées de l'image; - une approche fondée sur les ondelettes pour le codage de la partie "cartoon" (ou non-texturée) de l' image. Dans ce cadre, nous proposons une nouvelle approche pour la décomposition d'une image dans une partie texturée et une partie non-texturée fondée sur la régularité locale. Chaque partie est ensuite codée à l'aide de sa représentation particulièreIn this thesis we propose new parametric models in signal and image processing based on the Wold decomposition of stationary stochastic processes. These models rely upon several theoretical results from functional and harmonic analysis, wavelet analysis and the theory of stochastic fields, The first chapter presents the theoretical background of the linear prediction for stationary processes and of the Wold decomposition theorems in 1-D and n-D. It is shown how the different parts of the decomposition are obtained and represented, by the means of the unitary orbit representation of stationary processes, the Kolmogorov canonical model and Szego-type extensions. The second chapter deals with a spectral factorisation approach of the power spectral density used for the parameter estimation of Moving Avergage (MA), AutoRegressif (AR) and ARMA models. The method uses the Poisson integral representation in Hardy spaces in order to estimate an outer transfer function from its power spectral density. - Simulators for Rayleigh fading channels (1-D). - A scheme for the Wold decomposition for texture images (2-D). In the third chapter we deal with hybrid models for image representation and compression. We propose a compression scheme which jointly uses, on one hand, Wold models for textured regions of the image, and on the other hand a wavelet-based approach for coding the 'cartoon' (or non-textured) part of the image. In this context, we propose a new algorithm for the decomposing images in a textured part and a non-textured part. The separate parts are then coded with the appropriate representation
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Morris, Andrew Jordan. "Local Hardy spaces and quadratic estimates for Dirac type operators on Riemannian manifolds." Phd thesis, 2010. http://hdl.handle.net/1885/8864.
Повний текст джерелаАнотація:
The connection between quadratic estimates and the existence of a bounded holomorphic functional calculus of an operator provides a framework for applying harmonic analysis to the theory of differential operators. This is a generalization of the connection between Littlewood--Paley--Stein estimates and the functional calculus provided by the Fourier transform. We use the former approach in this thesis to study first-order differential operators on Riemannian manifolds. The theory developed is local in the sense that it does not depend on the spectrum of the operator in a neighbourhood of the origin. When we apply harmonic analysis to obtain estimates, the local theory only requires that we do so up to a finite scale. This allows us to consider manifolds with exponential volume growth in situations where the global theory requires polynomial volume growth.
A holomorphic functional calculus is constructed for operators on a reflexive Banach space that are bisectorial except possibly in a neighbourhood of the origin. We prove that this functional calculus is bounded if and only if certain local quadratic estimates hold. For operators with spectrum in a neighbourhood of the origin, the results are weaker than those for bisectorial operators. For operators with a spectral gap in a neighbourhood of the origin, the results are stronger. In each case, however, local quadratic estimates are a more appropriate tool than standard quadratic estimates for establishing that the functional calculus is bounded.
This theory allows us to define local Hardy spaces of differential forms that are adapted to a class of first-order differential operators on a complete Riemannian manifold with at most exponential volume growth. The local geometric Riesz transform associated with the Hodge--Dirac operator is bounded on these spaces provided that a certain condition on the exponential growth of the manifold is satisfied. A characterisation of these spaces in terms of local molecules is also obtained. These results can be viewed as the localisation of those for the Hardy spaces of differential forms introduced by Auscher, McIntosh and Russ.
Finally, we introduce a class of first-order differential operators that act on the trivial bundle over a complete Riemannian manifold with at most exponential volume growth and on which a local Poincar\'{e} inequality holds. A local quadratic estimate is established for certain perturbations of these operators. As an application, we solve the Kato square root problem for divergence form operators on complete Riemannian manifolds with Ricci curvature bounded below that are embedded in Euclidean space with a uniformly bounded second fundamental form. This is based on the framework for Dirac type operators that was introduced by Axelsson, Keith and McIntosh.
Книги з теми "Local Hardy spaces"
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Copeland, Nicholas. The Democracy Development Machine. Cornell University Press, 2019. http://dx.doi.org/10.7591/cornell/9781501736056.001.0001.
Повний текст джерелаАнотація:
What forces hinder decolonization efforts on the neoliberal terrain? In the aftermath of a genocidal scorched earth campaign, Mayas in the town of San Pedro Necta encountered a formidable democracy-development machine designed to displace radical class politics into private market advancement and local, indigenous-led electoral politics. Sampedranos regarded neoliberal democracy and development not as empty, depoliticized forms or colonial impositions, but as hard-won victories that met immediate needs and echoed revolutionary and local struggles. This historical ethnography examines how these governmentalized spaces fell short, simultaneously enabling and disfiguring an ethnic resurgence that fractured in a dispiriting atmosphere of pessimism, self-interest, deception, and mistrust. These dynamics fueled authoritarian populism but also radical reimaginings of democracy and development from below. These findings shed new light on rural politics in Guatemala and across neoliberal and post-conflict settings.
Частини книг з теми "Local Hardy spaces"
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Yang, Dachun, Yiyu Liang, and Luong Dang Ky. "Local Musielak-Orlicz Hardy Spaces." In Lecture Notes in Mathematics, 255–327. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-54361-1_8.
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Chang, Der-Chen, Galia Dafni, and Hong Yue. "Nonhomogeneous div-curl decompositions for local Hardy spaces on a domain." In CRM Proceedings and Lecture Notes, 153–63. Providence, Rhode Island: American Mathematical Society, 2010. http://dx.doi.org/10.1090/crmp/051/11.
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Yang, Dachun, Dongyong Yang, and Guoen Hu. "The Local Atomic Hardy Space h 1(μ)." In The Hardy Space H1 with Non-doubling Measures and Their Applications, 137–214. Cham: Springer International Publishing, 2013. http://dx.doi.org/10.1007/978-3-319-00825-7_4.
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Formato, Enrico. "New Urbanization Phenomena and Potential Landscapes: Rhizomatic Grids and Asymmetrical Clusters." In Regenerative Territories, 135–45. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-78536-9_8.
Повний текст джерелаАнотація:
AbstractMore and more nowadays, the Circular Economy is at the heart of European public policies. As a result of the “Next Generation EU” Recovery Plans, a huge amount of financial resources will be available in the coming years to give shape the concept of “ecological transition". For that purpose, radical vision and operational concreteness are needed.In order to strengthen the territorial dimension of public policies aimed at ecological transition, the paper points to consider the status quo of the European territory, looking for recurring elements and differences. In this perspective, a return of “hard” urban studies, focusing on the issues of land ownership, land parcelling, infrastructural and urbanization procedures (and their relationships with the environment and the landscape) should be conducted at the European scale.A central role for the future of contemporary territories is recognized in the so-called “fringe area”, the part of the urban region where patterns of building development and unbuilt space interwave: its intermediary character, as a place between the compact city and the suburban countryside, makes this zone favourable to the collaboration between the two worlds. In addition, its easy accessibility from both the denser contexts and the outer areas makes it the perfect place to locate the equipment required to create short supply chains, so relevant for the circular economy and the ecological transition.These transition areas need to be rethought as new collective spaces of the contemporary city, areas for the proliferation of biodiversity, inhibited from settlement increase and subject to restrictions on car traffic. In them, the circular dimension of the new green economy could give shape to certain spatial conditions and new landscapes.Two main spatial models can describe this sustainable reform of the peri-urban territories. The first one assumes the figure of the “cluster”: a territorially and functionally defined region with one or more reference centres and an edge marking the discontinuity from other clusters. The second model is based on the figure of the “grid”: an unlimited mesh, which gives measure and organizes space according to a replicable and open system. This spatiality is built on a redundant and weak infrastructure, devoid of hierarchy, which can give rise to a sponge rich in pores, with neither internal nor external boundaries.The concept of the materiality also deals with the physical status of each context where the clusters of shortening flows would define local metabolisms, self-sufficient, marked by the use and recycling of what can be produced or “extracted” in the cluster itself. The closing of short supply chains for the use and recycling of materials, also with reference to the construction cycle and CDW recycling, would have direct consequences on the architectural character of the new arrangements: a kind of hyper-contextualism in which the landscape takes on grains, colours, materiality, closely linked to the local condition.Finally, a reflection on the rationales of the project is outlined. What is proposed, in fact, requires going beyond the traditional way in which the project has been conceived. In fact, these urban reconfiguration processes, structurally open to uncertainty, would take advantage of a programmatic choice of spatial incompleteness: a condition of “unfinished”, open to the accumulation over time of functions, forms, aggregations and densifications.
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"Classical (Local) Hardy Inequalities." In Fractional Sobolev Spaces and Inequalities, 75–103. Cambridge University Press, 2022. http://dx.doi.org/10.1017/9781009254625.007.
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Ferzacca, Steve. "Noisy Places, Noisy People." In The Hard State, Soft City of Singapore. Nieuwe Prinsengracht 89 1018 VR Amsterdam Nederland: Amsterdam University Press, 2020. http://dx.doi.org/10.5117/9789463729505_ch07.
Повний текст джерелаАнотація:
Making noise in a basement corner of an ageing mall in Singapore affords a small community of musicians, family and friends a gathering place to meet, eat, drink, smoke and jam loud amplified music. The Doghouse is a ‘device of saturation’, a way of making sense of self and others: it exists so that this sonic community can exact possibilities and creative potential within the limits of official use of public space. Bodily scales are realized in cosmopolitan spaces where local and global interrogations in dialogue, in space, and among things, make trouble and meaning. And so some noisy people have, for now, found a playground where their urban dreams and aspirations are imagined and realized.
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Fern, Hoe Su. "Place Management/Making." In The Hard State, Soft City of Singapore. Nieuwe Prinsengracht 89 1018 VR Amsterdam Nederland: Amsterdam University Press, 2020. http://dx.doi.org/10.5117/9789463729505_ch08.
Повний текст джерелаАнотація:
This chapter examines the role of the arts and artists in rejuvenating urban spaces in Singapore, where place management ideas are currently being used to rejuvenate parts of the city centre. Coexisting alongside state-driven initiatives are artist-led strategies where local art practitioners and organizations activate latent and/or under-utilized spaces. Through an analysis of policy documents and qualitative ethnographic fieldwork, this study explores the interplay between top-down aspirations and formal place management efforts, and the organic ways artists have activated and engaged with spaces. Ultimately, I argue that there is a need to balance formal governance structures with more support for artists engaging in organic, ground-up initiatives.
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Long, Paul, and Saskia Warren. "‘An area lacking cultural activity’: researching cultural lives in urban space." In Cultural Intermediaries Connecting Communities, 97–114. Policy Press, 2019. http://dx.doi.org/10.1332/policypress/9781447344995.003.0006.
Повний текст джерелаАнотація:
Focussed on the Balsall Heath area of Birmingham, this chapter explores the specific ways in which individuals are situated by intermediation practices, policy imperatives, discourses and imaginaries as cultural consumers, participants and sometimes producers. In tandem with the attention afforded its demographic diversity, levels of deprivation Balsall Heath has been an object of cultural policy initiatives seeking to engage disadvantaged and ‘hard-to-reach’ communities. The chapter first outlines the particular socio-economic character of the area and discusses the method of walking interviews that was employed to engage with residents. The method does not offer am exhaustive picture of cultural engagement, conceived instead as a means of ‘thinking with’ participants within a local landscape of social, material and religious relations that shape individual agency.
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Inoue, Mayumo, and Steve Choe. "Introduction." In Beyond Imperial Aesthetics, 1–20. Hong Kong University Press, 2019. http://dx.doi.org/10.5790/hongkong/9789888455874.003.0001.
Повний текст джерелаАнотація:
This introductory essay foregrounds "aesthetics" as a fundamental mode of inquiry that enables scholars to question and overcome many "imperial" assumptions that still govern East Asia studies to this day. Through this renewed focus on art and aesthetics in the age of neoliberalism, the chapter seeks to extend the earlier efforts to critique the area studies paradigm and its methodological nationalism by Naoki Sakai, Rey Chow, Harry Harootunian, and Masao Miyoshi. By underscoring the ways in which global protocols of capitalist accumulation, biopolitics, and warfare require their local legitimation through the fundamentally aesthetic figures of nation, race, and culture, this essay theorizes toward a critically liberating mode of aesthetics that seeks to undo the imperial categories of thinking and politics in East Asia. Notably, this chapter critiques how imperial aesthetics often works in the guise of local culturalism, making the task of aesthetic critique more urgent in East Asian and North American intellectual space.
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Ibrahim, Ahmed Sh. "The Sharia Courts of Mogadishu." In War and Peace in Somalia, 147–54. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780190947910.003.0012.
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This chapter considers whether there are lessons to be learned from the experience of the Sharia courts of Mogadishu that are relevant to peace and reconciliation in Somalia. These courts emerged in 1992 in response to the collapse of the state. It argues the Sharia courts succeeded where others failed because they simultaneously built on known cultural and religious norms, authorities, and practices, while at the same time pragmatically responding to the demands of the moment. Two of the most important lessons from the experience of the courts are: (a) justice in Somalia is inseparable from practices and discourses associated with the Sharia; and (b) it is hard to establish legitimate political authority if the political space and political leaders are viewed by local people to contradict and counteract the norms of the Sharia.
Тези доповідей конференцій з теми "Local Hardy spaces"
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Shen, Tao, Tianyi Zhou, Guodong Long, Jing Jiang, Sen Wang, and Chengqi Zhang. "Reinforced Self-Attention Network: a Hybrid of Hard and Soft Attention for Sequence Modeling." In Twenty-Seventh International Joint Conference on Artificial Intelligence {IJCAI-18}. California: International Joint Conferences on Artificial Intelligence Organization, 2018. http://dx.doi.org/10.24963/ijcai.2018/604.
Повний текст джерелаАнотація:
Many natural language processing tasks solely rely on sparse dependencies between a few tokens in a sentence. Soft attention mechanisms show promising performance in modeling local/global dependencies by soft probabilities between every two tokens, but they are not effective and efficient when applied to long sentences. By contrast, hard attention mechanisms directly select a subset of tokens but are difficult and inefficient to train due to their combinatorial nature. In this paper, we integrate both soft and hard attention into one context fusion model, "reinforced self-attention (ReSA)", for the mutual benefit of each other. In ReSA, a hard attention trims a sequence for a soft self-attention to process, while the soft attention feeds reward signals back to facilitate the training of the hard one. For this purpose, we develop a novel hard attention called "reinforced sequence sampling (RSS)", selecting tokens in parallel and trained via policy gradient. Using two RSS modules, ReSA efficiently extracts the sparse dependencies between each pair of selected tokens. We finally propose an RNN/CNN-free sentence-encoding model, "reinforced self-attention network (ReSAN)", solely based on ReSA. It achieves state-of-the-art performance on both the Stanford Natural Language Inference (SNLI) and the Sentences Involving Compositional Knowledge (SICK) datasets.
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Min, Hequn, Xiaoyang Huang, and Qide Zhang. "Virtual Sensing in Local Active Suppression on Pressure Fluctuations for Controlling Flow-Induced Vibration in Hard Disk Drives." In ASME 2012 Noise Control and Acoustics Division Conference at InterNoise 2012. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/ncad2012-1403.
Повний текст джерелаАнотація:
Numerical simulations are presented on a feedback active control strategy for flow-induced off-track vibration of the head gimbals assembly (HGA) supporting the slider in hard disk drives, through suppressing pressure fluctuations around the HGA. A virtual sensing method is employed to enable the feedback signal changeable from pressure fluctuations at the physical sensor position to those at single “virtual sensor” positions closely around the HGA or a spatial average of pressure fluctuations along an HGA surface. Based on a linear control methodology, performance of the proposed active control strategy with different feedback signals has been investigated in two-dimensional simulations, where a physical pressure sensor and a pressure actuator are assumed on the inner-surface of the HDD cover to detect the pressure fluctuations and to actuate active pressure oscillations into HDD space respectively. The results show effective control on the HGA off-track vibration when the feedback signal is configured to minimize pressure fluctuations at specific positions closely around the HGA, such as the wake region. It is also shown that satisfying control effect can be achieved on the HGA off-track vibration in the global spectrum when the feedback signal is configured to minimize the spatial average of pressure fluctuations along the upper surface of the HGA.
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Teodorescu, M., H. Rahnejat, Moshe Brand, and Jacob Rosen. "Post-Angioplastic Contact Mechanics With Different Levels of Artherosclerotic Plaque." In STLE/ASME 2010 International Joint Tribology Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/ijtc2010-41145.
Повний текст джерелаАнотація:
The main goal of balloon angioplasty is to extend the active cross-section of a partly blocked artery. In the last stage of the medical operation, a metallic frame (stent) is introduced in the open space of the artery (lumen) and expanded to the desired diameter. It is generally accepted that some of the main causes of post-angioplasty restenosis are the global stresses induced in the artery by the expanding stent and the local interaction between the stent and the arterial wall. In a blocked artery a thick layer of hard plaque deposition usually covers a significant section of the wall. Therefore, to choose an appropriate stent and improve upon the angioplasty success rate, a fundamental understanding of the local interaction between the stent and the plaque, as well as between the stent and the healthy wall is vital. The goal of the present study is to find a correlation between the local thickness of the plaque layer, contact geometry and the stent/artery radial mismatch.
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Ogot, Madara M., and Satnam Alag. "A Stochastic Methodology for the Optimal Analytical Synthesis of Planar Mechanisms." In ASME 1993 Design Technical Conferences. American Society of Mechanical Engineers, 1993. http://dx.doi.org/10.1115/detc1993-0334.
Повний текст джерелаАнотація:
Abstract This paper presents a stochastic based methodology for the optimal synthesis of planar mechanisms. The approach is fully automated, relatively simple to use and flexible. The methodology employs an analytical synthesis approach based on the complex number theory, to synthesize the desired mechanism based on a relatively small number of prescribed positions (hard precision points – satisfied exactly). The quality of the synthesized mechanism is then optimized at an arbitrary number of prescribed positions (soft precision points – approximately satisfied). In this manner, the number of design variables is kept relatively low without compromising on the quality of the final solution. A ‘global’ stochastic optimization approach is employed to assign values to the free choices in the analytical synthesis portion, thereby effectively guiding the design process through the often highly non-linear design space. Thus the problems associated with local minima are addressed and automation is achieved. In addition, this work investigates the feasibility of considering some of the hard precision points as design variables (variable hard precision points).
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Wu, Zheng-Fan, Hui Xue, and Weimin Bai. "Learning Deeper Non-Monotonic Networks by Softly Transferring Solution Space." In Thirtieth International Joint Conference on Artificial Intelligence {IJCAI-21}. California: International Joint Conferences on Artificial Intelligence Organization, 2021. http://dx.doi.org/10.24963/ijcai.2021/440.
Повний текст джерелаАнотація:
Different from popular neural networks using quasiconvex activations, non-monotonic networks activated by periodic nonlinearities have emerged as a more competitive paradigm, offering revolutionary benefits: 1) compactly characterizing high-frequency patterns; 2) precisely representing high-order derivatives. Nevertheless, they are also well-known for being hard to train, due to easily over-fitting dissonant noise and only allowing for tiny architectures (shallower than 5 layers). The fundamental bottleneck is that the periodicity leads to many poor and dense local minima in solution space. The direction and norm of gradient oscillate continually during error backpropagation. Thus non-monotonic networks are prematurely stuck in these local minima, and leave out effective error feedback. To alleviate the optimization dilemma, in this paper, we propose a non-trivial soft transfer approach. It smooths their solution space close to that of monotonic ones in the beginning, and then improve their representational properties by transferring the solutions from the neural space of monotonic neurons to the Fourier space of non-monotonic neurons as the training continues. The soft transfer consists of two core components: 1) a rectified concrete gate is constructed to characterize the state of each neuron; 2) a variational Bayesian learning framework is proposed to dynamically balance the empirical risk and the intensity of transfer. We provide comprehensive empirical evidence showing that the soft transfer not only reduces the risk of non-monotonic networks on over-fitting noise, but also helps them scale to much deeper architectures (more than 100 layers) achieving the new state-of-the-art performance.
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La Malfa, Emanuele, Rhiannon Michelmore, Agnieszka M. Zbrzezny, Nicola Paoletti, and Marta Kwiatkowska. "On Guaranteed Optimal Robust Explanations for NLP Models." In Thirtieth International Joint Conference on Artificial Intelligence {IJCAI-21}. California: International Joint Conferences on Artificial Intelligence Organization, 2021. http://dx.doi.org/10.24963/ijcai.2021/366.
Повний текст джерелаАнотація:
We build on abduction-based explanations for machine learning and develop a method for computing local explanations for neural network models in natural language processing (NLP). Our explanations comprise a subset of the words of the input text that satisfies two key features: optimality w.r.t. a user-defined cost function, such as the length of explanation, and robustness, in that they ensure prediction invariance for any bounded perturbation in the embedding space of the left-out words. We present two solution algorithms, respectively based on implicit hitting sets and maximum universal subsets, introducing a number of algorithmic improvements to speed up convergence of hard instances. We show how our method can be configured with different perturbation sets in the embedded space and used to detect bias in predictions by enforcing include/exclude constraints on biased terms, as well as to enhance existing heuristic-based NLP explanation frameworks such as Anchors. We evaluate our framework on three widely used sentiment analysis tasks and texts of up to 100 words from SST, Twitter and IMDB datasets, demonstrating the effectiveness of the derived explanations.
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Prabhu, Pratik, and Juan Miguel Abad. "No Tag to Hard Tag - Case History About Effective Cement Plug Placement Techniques." In SPE/IADC Middle East Drilling Technology Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/202158-ms.
Повний текст джерелаАнотація:
Abstract The success or failure of cement plugs are known to alter the timeline of an oil well; not to mention the additional costs and NPT associated with the rig activities. Unsuccessful cement plug costs oil companies considerable amount of capital both in extra rig time and service company expenses. Suggested procedures for placing cement plugs have been presented in number of papers - comprising of slurry design, spacer recommendations, laboratory testing and placement techniques. However, it is very easy to deviate from these standard practices due to over confidence, negligence or both. In Mexico, it was observed that the success rate of placing cement plugs dropped due to operational and engineering design shortcomings. Towards the end of 2018 there were several unsuccessful cement plug jobs that questioned the regular plug procedures. Careful analysis of the past mistakes led to the conclusion that an effective approach to alter the local plug placement practices was necessary. An updated cement plug placement software was used in conjunction with strict standard practices that turned around the trend and enabled consistent successful placement of cement plugs in the first attempt itself. A detailed yet simple approach towards cement plugs was adopted in both engineering design and operational execution. Additionally the updated plug placement software ensured accurate prediction of the cement plug top; that was confirmed by the actual tag of the plug. This paper will enlist the major analysis carried out on the unsuccessful plug jobs and highlight the different techniques that were adopted in the subsequent jobs to ensure successful placement and tagging of the cement plug. The paper will also focus on how the plug placement software's new additional features have made a significant contribution to this success story.
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Paruchuru, Satya Prasad, Siva Kalyani Koneti, Deepthi Jammula, and Jashwitha Nuthalapati. "Estimation and Feasibility of Generating Power Using Tidal Energy." In ASME 2020 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/imece2020-23721.
Повний текст джерелаАнотація:
Abstract Capturing the tidal energy is one of the ways of tapping natural and renewable energy which do not involve the cost of working fluid/ fuel. The present work focuses on some of the feasibility aspects of setting up of major tidal power plants along the seacoast. Besides, the present study synergizes on methods of estimating the power-producing capacities in regions along the seacoast. Estimation of power-producing capacities, calendar month-wise, and lunar month-wise gave handy information. Also, the estimation of power-producing capacities of different regions along a location gave clarity on the probable regions of interest for producing power simultaneously. A comparison of the estimates with the details of the literature authenticated the study. A discussion of producing more tidal power in specific locations gave insights into the aspects that may have been ignored in the literature. Geographic restrictions along the local seacoast like identifying the security-sensitive regions rationalized the estimating procedures. The paper includes a discussion of various factors that address the feasibility concerns. The study supposedly helps space exploration too.
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Daneshmand, Farhang, Abdolaziz Abdollahi, Mehdi Liaghat, and Yousef Bazargan Lari. "Free Vibration Analysis of Frame Structures Using BSWI Method." In ASME 2008 International Mechanical Engineering Congress and Exposition. ASMEDC, 2008. http://dx.doi.org/10.1115/imece2008-68417.
Повний текст джерелаАнотація:
Vibration analysis for complicated structures, or for problems requiring large numbers of modes, always requires fine meshing or using higher order polynomials as shape functions in conventional finite element analysis. Since it is hard to predict the vibration mode a priori for a complex structure, a uniform fine mesh is generally used which wastes a lot of degrees of freedom to explore some local modes. By the present wavelets element approach, the structural vibration can be analyzed by coarse mesh first and the results can be improved adaptively by multi-level refining the required parts of the model. This will provide accurate data with less degrees of freedom and computation. The scaling functions of B-spline wavelet on the interval (BSWI) as trial functions that combines the versatility of the finite element method with the accuracy of B-spline functions approximation and the multiresolution strategy of wavelets is used for frame structures vibration analysis. Instead of traditional polynomial interpolation, scaling functions at the certain scale have been adopted to form the shape functions and construct wavelet-based elements. Unlike the process of wavelets added directly in the other wavelet numerical methods, the element displacement field represented by the coefficients of wavelets expansions is transformed from wavelet space to physical space via the corresponding transformation matrix. To verify the proposed method, the vibrations of a cantilever beam and a plane structures are studied in the present paper. The analyses and results of these problems display the multi-level procedure and wavelet local improvement. The formulation process is as simple as the conventional finite element method except including transfer matrices to compute the coupled effect between different resolution levels. This advantage makes the method more competitive for adaptive finite element analysis. The results also show good agreement with those obtained from the classical finite element method and analytical solutions.
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Ilstad, Trygve, Tore So̸reide, and Finn Gunnar Nielsen. "Fatigue Calculations of Multi-Mode VIV." In ASME 2005 24th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2005. http://dx.doi.org/10.1115/omae2005-67540.
Повний текст джерелаАнотація:
Pipelines on undulating seabed may be subject to free-span areas where interaction between VIV response of several modes occurs, including both single and multi-spans. Within the project Ormen Lange a model test program, as completed in 2004, was performed to investigate this phenomena. The implementation of the test results into detail design went via an Ormen Lange specific design guideline in which the general analysis flow is given. However, taking the mode interaction effects from the tests into the actual routing makes the need for additional evaluations and generalisation on dynamic system of interacting spans. A dynamic system represents a set of spans were the eigenmodes interact physically and not only mathematically in computation of the eigenmodes over a long pipeline section. For a single span case we find that the modes are well separated while for multi-span problems modes are close in frequencies. A clear criterion and limitation on dynamic system to be considered becomes vital. The relative effect of inline and cross flow VIV in actual design depends on the SN-curves at hand. The general trend is that inline generated fatigue takes over for corrosion sensitive problems covering operation phase, whereas preliminary phases may be governed by cross flow response. The modelling of pipe-soil interaction at shoulders is vital for the multi-span response characteristics, the experience being that softer soil gives minor span interaction. The soft soil gives deeper pipeline penetration and more uniform support stiffness all along the shoulder than the hard soil for which local reactions occur more like pinned supports.
Звіти організацій з теми "Local Hardy spaces"
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Adlakha, Deepi, Jane Clarke, Perla Mansour, and Mark Tully. Walk-along and cycle-along: Assessing the benefits of the Connswater Community Greenway in Belfast, UK. Property Research Trust, 2021. http://dx.doi.org/10.52915/ghcj1777.
Повний текст джерелаАнотація:
Physical inactivity is a risk factor for numerous chronic diseases, and a mounting global health problem. It is likely that the outdoor physical environment, together with social environmental factors, has a tendency to either promote or discourage physical activity, not least in cities and other urban areas. However, the evidence base on this is sparse, making it hard to identify the best policy interventions to make, at the local or city level. This study seeks to assess the impact of one such intervention, the Connswater Community Greenway CCG), in Belfast, in Northern Ireland, UK. To do that it uses innovative methodologies, ‘Walk-along’ and ‘Cycle-along’ that involve wearable sensors and video footages, to improve our understanding of the impact of the CCG on local residents. The findings suggest that four characteristics of the CCG affect people’s activity and the benefits that the CCG created. These are physical factors, social factors, policy factors and individual factors. Each of these has many elements, with different impacts on different people using the greenway.