8,340 research outputs found

    Constrained Texture Mapping And Foldover-free Condition

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    Texture mapping has been widely used in image processing and graphics to enhance the realism of CG scenes. However to perfectly match the feature points of a 3D model with the corresponding pixels in texture images, the parameterisation which maps a 3D mesh to the texture space must satisfy the positional constraints. Despite numerous research efforts, the construction of a mathematically robust foldover-free parameterisation subject to internal constraints is still a remaining issue. In this paper, we address this challenge by developing a two-step parameterisation method. First, we produce an initial parameterisation with a method traditionally used to solve structural engineering problems, called the bar-network. We then derive a mathematical foldover-free condition, which is incorporated into a Radial Basis Function based scheme. This method is therefore able to guarantee that the resulting parameterization meets the hard constraints without foldovers

    Force transmissibility and vibration power flow behaviour of inerter-based vibration isolators

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    This paper investigates the dynamics and performance of inerter-based vibration isolators. Force / displacement transmissibility and vibration power flow are obtained to evaluate the isolation performance. Both force and motion excitations are considered. It is demonstrated that the use of inerters can enhance vibration isolation performance by enlarging the frequency band of effective vibration isolation. It is found that adding inerters can introduce anti-resonances in the frequency-response curves and in the curves of the force and displacement transmissibility such that vibration transmission can be suppressed at interested excitation frequencies. It is found that the introduction of inerters enhances inertial coupling and thus have a large influence on the dynamic behaviour at high frequencies. It is shown that force and displacement transmissibility increases with the excitation frequency and tends to an asymptotic value as the excitation frequency increases. In the high-frequency range, it was shown that adding inerters can result in a lower level of input power. These findings provide a better understanding of the effects of introducing inerters to vibration isolation and demonstrate the performance benefits of inerter-based vibration isolators

    Somatization vs. Psychologization of Emotional Distress: A Paradigmatic Example for Cultural Psychopathology

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    This paper describes the developing area of cultural psychopathology, an interdisciplinary field of study focusing on the ways in which cultural factors contribute to the experience and expression of psychological distress. We begin by outlining two approaches, often competing, in order to provide a background to some of the issues that complicate the field. The main section of the paper is devoted to a discussion of depression in Chinese culture as an example of the types of questions that can be studied. Here, we start with a review of the epidemiological literature, suggesting low rates of depression in China, and move to the most commonly cited explanation, namely that Chinese individuals with depression present this distress in a physical way. Different explanations of this phenomenon, known as somatization, are explored and reconceptualized according to an increasingly important model for cross-cultural psychologists: the cultural constitution of the self. We close by discussing some of the contributions, both theoretical and methodological, that can be made by cross-cultural psychologists to researchers in cultural psychopathology

    Beads-on-String Model for Virtual Rectum Surgery Simulation

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    A beads-on-string model is proposed to handle the deformation and collision of the rectum in virtual surgery simulation. The idea is firstly inspired by the observation of the similarity in shape shared by a rectum with regular bulges and a string of beads. It is beneficial to introduce an additional layer of beads, which provides an interface to map the deformation of centreline to the associated mesh in an elegant manner and a bounding volume approximation in collision handling. Our approach is carefully crafted to achieve high computational efficiency and retain its physical basis. It can be implemented for real time surgery simulation application

    Wavefront image sensor chip

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    We report the implementation of an image sensor chip, termed wavefront image sensor chip (WIS), that can measure both intensity/amplitude and phase front variations of a light wave separately and quantitatively. By monitoring the tightly confined transmitted light spots through a circular aperture grid in a high Fresnel number regime, we can measure both intensity and phase front variations with a high sampling density (11 ”m) and high sensitivity (the sensitivity of normalized phase gradient measurement is 0.1 mrad under the typical working condition). By using WIS in a standard microscope, we can collect both bright-field (transmitted light intensity) and normalized phase gradient images. Our experiments further demonstrate that the normalized phase gradient images of polystyrene microspheres, unstained and stained starfish embryos, and strongly birefringent potato starch granules are improved versions of their corresponding differential interference contrast (DIC) microscope images in that they are artifact-free and quantitative. Besides phase microscopy, WIS can benefit machine recognition, object ranging, and texture assessment for a variety of applications

    EIGEN: Ecologically-Inspired GENetic Approach for Neural Network Structure Searching from Scratch

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    Designing the structure of neural networks is considered one of the most challenging tasks in deep learning, especially when there is few prior knowledge about the task domain. In this paper, we propose an Ecologically-Inspired GENetic (EIGEN) approach that uses the concept of succession, extinction, mimicry, and gene duplication to search neural network structure from scratch with poorly initialized simple network and few constraints forced during the evolution, as we assume no prior knowledge about the task domain. Specifically, we first use primary succession to rapidly evolve a population of poorly initialized neural network structures into a more diverse population, followed by a secondary succession stage for fine-grained searching based on the networks from the primary succession. Extinction is applied in both stages to reduce computational cost. Mimicry is employed during the entire evolution process to help the inferior networks imitate the behavior of a superior network and gene duplication is utilized to duplicate the learned blocks of novel structures, both of which help to find better network structures. Experimental results show that our proposed approach can achieve similar or better performance compared to the existing genetic approaches with dramatically reduced computation cost. For example, the network discovered by our approach on CIFAR-100 dataset achieves 78.1% test accuracy under 120 GPU hours, compared to 77.0% test accuracy in more than 65, 536 GPU hours in [35].Comment: CVPR 201

    THE LAW OF ONE PRICE: DEVELOPED AND DEVELOPING COUNTRY MARKET INTEGRATION

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    The Law of One Price (LOP) is important to models of international trade and exchange rate determination. This study investigates a variant of the LOP applied to developed and developing countries. The competing hypothesis are (1) that one price prevails in both developed and developing countries and (2) that one price prevails in developed countries and another single price in developing countries. Using data from an internationally competitive commodity (soybean meal), we found evidence favors the first hypothesis, although two large developing countries under study are active participants in regional trade integration, which may bias them against the first hypothesis.law of one price, developing countries, error-correction model, directed graphs, Demand and Price Analysis,
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