129 research outputs found
Quantile and pseudo-Huber Tensor Decomposition
This paper studies the computational and statistical aspects of quantile and
pseudo-Huber tensor decomposition. The integrated investigation of
computational and statistical issues of robust tensor decomposition poses
challenges due to the non-smooth loss functions. We propose a projected
sub-gradient descent algorithm for tensor decomposition, equipped with either
the pseudo-Huber loss or the quantile loss. In the presence of both
heavy-tailed noise and Huber's contamination error, we demonstrate that our
algorithm exhibits a so-called phenomenon of two-phase convergence with a
carefully chosen step size schedule. The algorithm converges linearly and
delivers an estimator that is statistically optimal with respect to both the
heavy-tailed noise and arbitrary corruptions. Interestingly, our results
achieve the first minimax optimal rates under Huber's contamination model for
noisy tensor decomposition. Compared with existing literature, quantile tensor
decomposition removes the requirement of specifying a sparsity level in
advance, making it more flexible for practical use. We also demonstrate the
effectiveness of our algorithms in the presence of missing values. Our methods
are subsequently applied to the food balance dataset and the international
trade flow dataset, both of which yield intriguing findings
Personal Attribute Prediction from Conversations
Personal knowledge bases (PKBs) are critical to many applications, such as
Web-based chatbots and personalized recommendation. Conversations containing
rich personal knowledge can be regarded as a main source to populate the PKB.
Given a user, a user attribute, and user utterances from a conversational
system, we aim to predict the personal attribute value for the user, which is
helpful for the enrichment of PKBs. However, there are three issues existing in
previous studies: (1) manually labeled utterances are required for model
training; (2) personal attribute knowledge embedded in both utterances and
external resources is underutilized; (3) the performance on predicting some
difficult personal attributes is unsatisfactory. In this paper, we propose a
framework DSCGN based on the pre-trained language model with a noise-robust
loss function to predict personal attributes from conversations without
requiring any labeled utterances. We yield two categories of supervision, i.e.,
document-level supervision via a distant supervision strategy and
contextualized word-level supervision via a label guessing method, by mining
the personal attribute knowledge embedded in both unlabeled utterances and
external resources to fine-tune the language model. Extensive experiments over
two real-world data sets (i.e., a profession data set and a hobby data set)
show our framework obtains the best performance compared with all the twelve
baselines in terms of nDCG and MRR.Comment: Accepted by WWW'22 Companio
Low-resource Personal Attribute Prediction from Conversation
Personal knowledge bases (PKBs) are crucial for a broad range of applications
such as personalized recommendation and Web-based chatbots. A critical
challenge to build PKBs is extracting personal attribute knowledge from users'
conversation data. Given some users of a conversational system, a personal
attribute and these users' utterances, our goal is to predict the ranking of
the given personal attribute values for each user. Previous studies often rely
on a relative number of resources such as labeled utterances and external data,
yet the attribute knowledge embedded in unlabeled utterances is underutilized
and their performance of predicting some difficult personal attributes is still
unsatisfactory. In addition, it is found that some text classification methods
could be employed to resolve this task directly. However, they also perform not
well over those difficult personal attributes. In this paper, we propose a
novel framework PEARL to predict personal attributes from conversations by
leveraging the abundant personal attribute knowledge from utterances under a
low-resource setting in which no labeled utterances or external data are
utilized. PEARL combines the biterm semantic information with the word
co-occurrence information seamlessly via employing the updated prior attribute
knowledge to refine the biterm topic model's Gibbs sampling process in an
iterative manner. The extensive experimental results show that PEARL
outperforms all the baseline methods not only on the task of personal attribute
prediction from conversations over two data sets, but also on the more general
weakly supervised text classification task over one data set.Comment: Accepted by AAAI'2
Capturing Popularity Trends: A Simplistic Non-Personalized Approach for Enhanced Item Recommendation
Recommender systems have been gaining increasing research attention over the
years. Most existing recommendation methods focus on capturing users'
personalized preferences through historical user-item interactions, which may
potentially violate user privacy. Additionally, these approaches often overlook
the significance of the temporal fluctuation in item popularity that can sway
users' decision-making. To bridge this gap, we propose Popularity-Aware
Recommender (PARE), which makes non-personalized recommendations by predicting
the items that will attain the highest popularity. PARE consists of four
modules, each focusing on a different aspect: popularity history, temporal
impact, periodic impact, and side information. Finally, an attention layer is
leveraged to fuse the outputs of four modules. To our knowledge, this is the
first work to explicitly model item popularity in recommendation systems.
Extensive experiments show that PARE performs on par or even better than
sophisticated state-of-the-art recommendation methods. Since PARE prioritizes
item popularity over personalized user preferences, it can enhance existing
recommendation methods as a complementary component. Our experiments
demonstrate that integrating PARE with existing recommendation methods
significantly surpasses the performance of standalone models, highlighting
PARE's potential as a complement to existing recommendation methods.
Furthermore, the simplicity of PARE makes it immensely practical for industrial
applications and a valuable baseline for future research.Comment: 9 pages, 5 figure
Effect of low-level laser therapy on tooth-related pain and somatosensory function evoked by orthodontic treatment
Vimentin intermediate filaments and filamentous actin form unexpected interpenetrating networks that redefine the cell cortex
The cytoskeleton of eukaryotic cells is primarily composed of networks of filamentous proteins, F-actin, microtubules, and intermediate filaments. Interactions among the cytoskeletal components are important in determining cell structure and in regulating cell functions. For example, F-actin and microtubules work together to control cell shape and polarity, while the subcellular organization and transport of vimentin intermediate filament (VIF) networks depend on their interactions with microtubules. However, it is generally thought that F-actin and VIFs form two coexisting but separate networks that are independent due to observed differences in their spatial distribution and functions. In this paper, we present a closer investigation of both the structural and functional interplay between the F-actin and VIF cytoskeletal networks. We characterize the structure of VIFs and F-actin networks within the cell cortex using structured illumination microscopy and cryo-electron tomography. We find that VIFs and F-actin form an interpenetrating network (IPN) with interactions at multiple length scales, and VIFs are integral components of F-actin stress fibers. From measurements of recovery of cell contractility after transient stretching, we find that the IPN structure results in enhanced contractile forces and contributes to cell resilience. Studies of reconstituted networks and dynamic measurements in cells suggest direct and specific associations between VIFs and F-actin. From these results, we conclude that VIFs and F-actin work synergistically, both in their structure and in their function. These results profoundly alter our understanding of the contributions of the components of the cytoskeleton, particularly the interactions between intermediate filaments and F-actin
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On-Chip Super-Resolution Imaging with Fluorescent Polymer Films
Wide field of view (FOV), label-free super-resolution imaging is demonstrated using a specially designed waveguide chip that can illuminate a sample with multi-colour evanescent waves travelling along different directions. The method is enabled by a polymer fluorescent film which emits over a broad wavelength range. Its polygonal geometry ensures coverage over all illumination directions, enabling high fidelity image reconstruction whilst minimizing distortion and image blurring. By frequency shifting and iterative stitching of different spatial frequencies in Fourier space, the reconstruction of two dimensional samples is achieved without distortion over wide FOVs. The fabrication process is facile and compatible with conventional semiconductor-fabrication methods. The super-resolution chip (SRC) can thus be produced with high yield, offer opportunities for potential conjunction of super-resolution techniques integrated optical circuits or for the development of single-use diagnostic kits
A geostationary orbit microwave multi-channel radiometer
The geostationary orbit microwave multi-channel radiometer has the advantages of high real-time performance and large coverage, which plays an important role in typhoon, strong precipitation detection, and medium-to-short-term meteorological/oceanic forecasting. However, due to the difficulty in engineering development of the payload, its application on-orbit has not yet been achieved at present. To satisfy the requirements of fine and quantitative application of satellite observation data, a geostationary orbit microwave multi-channel radiometer with a 10-m-caliber is developed, in which the spatial resolution at horizontal polarization is better than 24 km at 54 GHz. In geostationary orbit microwave multi-channel radiometer, a quasi-optical feed network covering nearly 28 frequency octave bands and ranging from 23.8 to 664 GHz is proposed to solve the technical problem of multi-frequency sharing in the system. Meanwhile, a high-precision reflector preparation method and a high-precision unfolding scheme are proposed, which are considered as a solution for the large-diameter reflector with a high maintaining surface accuracy. A high-precision antenna prototype with 0.54-m is developed, and the tests are performed to verify the key technologies, such as the preparation of high-precision grating reflectors at the micron level, high surface accuracy detection, and sub-millimeter wave antenna electrical performance testing. The results indicate that measured main beam efficiency of the 664 GHz antenna is better than 95.5%. In addition, the system sensitivity is greater than 1.5 K, and the calibration accuracy is better than 1.8 K, according to the results of an analysis of the multi-channel radiometer’s essential parameters and calibration errors
An ethylene biosynthesis enzyme controls quantitative variation in maize ear length and kernel yield.
Maize ear size and kernel number differ among lines, however, little is known about the molecular basis of ear length and its impact on kernel number. Here, we characterize a quantitative trait locus, qEL7, to identify a maize gene controlling ear length, flower number and fertility. qEL7 encodes 1-aminocyclopropane-1- carboxylate oxidase2 (ACO2), a gene that functions in the final step of ethylene biosynthesis and is expressed in specific domains in developing inflorescences. Confirmation of qEL7 by gene editing of ZmACO2 leads to a reduction in ethylene production in developing ears, and promotes meristem and flower development, resulting in a ~13.4% increase in grain yield per ear in hybrids lines. Our findings suggest that ethylene serves as a key signal in inflorescence development, affecting spikelet number, floral fertility, ear length and kernel number, and also provide a tool to improve grain productivity by optimizing ethylene levels in maize or in other cereals
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