7,387 research outputs found

    Discrete denoising of heterogenous two-dimensional data

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    We consider discrete denoising of two-dimensional data with characteristics that may be varying abruptly between regions. Using a quadtree decomposition technique and space-filling curves, we extend the recently developed S-DUDE (Shifting Discrete Universal DEnoiser), which was tailored to one-dimensional data, to the two-dimensional case. Our scheme competes with a genie that has access, in addition to the noisy data, also to the underlying noiseless data, and can employ mm different two-dimensional sliding window denoisers along mm distinct regions obtained by a quadtree decomposition with mm leaves, in a way that minimizes the overall loss. We show that, regardless of what the underlying noiseless data may be, the two-dimensional S-DUDE performs essentially as well as this genie, provided that the number of distinct regions satisfies m=o(n)m=o(n), where nn is the total size of the data. The resulting algorithm complexity is still linear in both nn and mm, as in the one-dimensional case. Our experimental results show that the two-dimensional S-DUDE can be effective when the characteristics of the underlying clean image vary across different regions in the data.Comment: 16 pages, submitted to IEEE Transactions on Information Theor

    Exploring E-cigarettes: Ingredients, Health Effects, and Considerations for Use

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    Electronic cigarettes, or e-cigarettes are becoming an increasingly popular nicotine delivery system, especially among adolescents and college aged students. They appeal to this population because they are new, are convenient to use, have appealing flavors, and are viewed as a cleaner, safer alternative to cigarettes. However, there are known ingredients in both the e-cigarette solution and vapors that have significant health effects and it is becoming an emerging public health issue that needs to be addressed. There is a gap in the knowledge about the potential harmful effects of e-cigarettes on both the part of the user and the healthcare providers who may need to counsel a user of e-cigarettes, since a lot of evidence is still emerging related to the health effects of e-cigarette use. To address this gap in knowledge, this paper summarizes some of the literature related to e-cigarette use, their health and safety effects that could be used to inform both users and healthcare providers, specifically nurses and nurse practitioners. There is still much to be learned about the long-term effects of e-cigarette use and what healthcare providers can do to minimize those effects

    Stability analysis and control for bipedal locomotion using energy methods

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    In this thesis, we investigate the stability of limit cycles of passive dynamic walking. The formation process of the limit cycles is approached from the view of energy interaction. We introduce for the first time the notion of the energy portrait analysis originated from the phase portrait. The energy plane is spanned by the total energy of the system and its derivative, and different energy trajectories represent the energy portrait in the plane. One of the advantages of this method is that the stability of the limit cycles can be easily shown in a 2D plane regardless of the dimension of the system. The energy portrait of passive dynamic walking reveals that the limit cycles are formed by the interaction between energy loss and energy gain during each cycle, and they are equal at equilibria in the energy plane. In addition, the energy portrait is exploited to examine the existence of semi-passive limit cycles generated using the energy supply only at the take-off phase. It is shown that the energy interaction at the ground contact compensates for the energy supply, which makes the total energy invariant yielding limit cycles. This result means that new limit cycles can be generated according to the energy supply without changing the ground slope, and level ground walking, whose energy gain at the contact phase is always zero, can be achieved without actuation during the swing phase. We design multiple switching controllers by virtue of this property to increase the basin of attraction. Multiple limit cycles are linearized using the Poincare map method, and the feedback gains are computed taking into account the robustness and actuator saturation. Once a trajectory diverges from a basin of attraction, we switch the current controller to one that includes the trajectory in its basin of attraction. Numerical simulations confirm that a set of limit cycles can be used to increase the basin of attraction further by switching the controllers one after another. To enhance our knowledge of the limit cycles, we performed sophisticated simulations and found all stable and unstable limit cycles from the various ground slopes not only for the symmetric legs but also for the unequal legs that cause gait asymmetries. As a result, we present a novel classification of the passive limit cycles showing six distinct groups that are consecutive and cyclical

    Health Concerns and Consumer Preferences for Soy Foods: Choice Modeling Approach

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    Consumer/Household Economics, Food Consumption/Nutrition/Food Safety,

    Bivariate Beta-LSTM

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    Long Short-Term Memory (LSTM) infers the long term dependency through a cell state maintained by the input and the forget gate structures, which models a gate output as a value in [0,1] through a sigmoid function. However, due to the graduality of the sigmoid function, the sigmoid gate is not flexible in representing multi-modality or skewness. Besides, the previous models lack modeling on the correlation between the gates, which would be a new method to adopt inductive bias for a relationship between previous and current input. This paper proposes a new gate structure with the bivariate Beta distribution. The proposed gate structure enables probabilistic modeling on the gates within the LSTM cell so that the modelers can customize the cell state flow with priors and distributions. Moreover, we theoretically show the higher upper bound of the gradient compared to the sigmoid function, and we empirically observed that the bivariate Beta distribution gate structure provides higher gradient values in training. We demonstrate the effectiveness of bivariate Beta gate structure on the sentence classification, image classification, polyphonic music modeling, and image caption generation.Comment: AAAI 202
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