950 research outputs found

    Clifford Analysis and Commutators on the Besov Spaces

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    AbstractWe study commutators between multiplication by a function, called the symbol, and Riesz transformations on the Besov spaces. We characterize symbols, by potential capacity, for which the associated commutators are bounded. Clifford analysis plays a key role in our approach

    Carleson Measures and Multipliers for Dirichlet Spaces

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    AbstractWe characterize Carleson measures on the Dirichlet spaces. Our result leads to necessary and sufficient conditions for multipliers of the Dirichlet spaces

    Physical Primitive Decomposition

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    Objects are made of parts, each with distinct geometry, physics, functionality, and affordances. Developing such a distributed, physical, interpretable representation of objects will facilitate intelligent agents to better explore and interact with the world. In this paper, we study physical primitive decomposition---understanding an object through its components, each with physical and geometric attributes. As annotated data for object parts and physics are rare, we propose a novel formulation that learns physical primitives by explaining both an object's appearance and its behaviors in physical events. Our model performs well on block towers and tools in both synthetic and real scenarios; we also demonstrate that visual and physical observations often provide complementary signals. We further present ablation and behavioral studies to better understand our model and contrast it with human performance.Comment: ECCV 2018. Project page: http://ppd.csail.mit.edu

    A New Approach of Dynamic Clustering Based on Particle Swarm Optimization and Application in Image Segmentation

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    This paper presents a new approach of dynamic clustering based on improved Particle Swarm Optimization (PSO) and which is applied to image segmentation (called DCPSONS). Firstly, the original PSO algorithm is improved by using diversity mechanism and neighborhood search strategy. The improved PSO is then combined with the well-known data clustering k-means algorithm for dynamic clustering problem where the number of clusters has not yet been known. Finally, DCPSONS is applied to image segmentation problem, in which the number of clusters is automatically determined. Experimental results in using sixteen benchmark data sets and several images of synthetic and natural benchmark data demonstrate that the proposed DCPSONS algorithm substantially outperforms other competitive algorithms in terms of accuracy and convergence rate

    Ownership structure, diversification strategy and firm performance - An empirical study on China's listed companies

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    Master'sMASTER OF SCIENCE (MANAGEMENT

    Unsupervised Discovery of Parts, Structure, and Dynamics

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    Humans easily recognize object parts and their hierarchical structure by watching how they move; they can then predict how each part moves in the future. In this paper, we propose a novel formulation that simultaneously learns a hierarchical, disentangled object representation and a dynamics model for object parts from unlabeled videos. Our Parts, Structure, and Dynamics (PSD) model learns to, first, recognize the object parts via a layered image representation; second, predict hierarchy via a structural descriptor that composes low-level concepts into a hierarchical structure; and third, model the system dynamics by predicting the future. Experiments on multiple real and synthetic datasets demonstrate that our PSD model works well on all three tasks: segmenting object parts, building their hierarchical structure, and capturing their motion distributions.Comment: ICLR 2019. The first two authors contributed equally to this wor

    Qinghai-Tibet Railway, China and the Solutions to Its Major Geotechnical Problems for Construction

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    The Qinghai-Tibet Railway (QTR) is the highest-elevation one for passenger trains in the world and the first railway to connect central China to Tibet. Construction of this railway starting in 2001 had to contend with major geotechnical challenges, such as permafrost, environmental protection and seismic hazards. Its completion in 2006 is a remarkable feat in the world’s railway construction history and crystallization of wisdom of human beings. In this paper, the planning and preparing history and the construction project of QTR are introduced. The major three thorny problems, permafrost, lack of oxygen and environmental frangibility for the construction and their solutions are presented, which are active methods of riprap roadbeds, heat pipe roadbed and bridges over land for permafrost, health care system for lack of oxygen and environmental protection measures for construction and operation. Seismic safety assessment was carried out for earthquake damage mitigation of the railway. The laboratory test, field test and observation, and it’s operation have shown that design, construction, and measures for earthquake hazards mitigation and environmental protection of the Qinghai-Tibet Railway are completely successful
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