3,887 research outputs found
Explaining Import Variety and Quality: The Role of the Income Distribution
We examine a generalized version of Flam and Helpmanâs (1987) model of vertical differentiation that maps cross-country differences in income distributions to variations in import variety and price distributions. The theoretical predictions are examined and confirmed using micro data on income from the Luxemburg Income Study for 30 countries over 20 years. The pairs of importers whose income distributions look more similar have more export partners in common and more similar import price distributions. Similarly, the importers whose income distributions look more like the world buy from more exporters and have import price distributions that look more like the world.
Who will win the Nobel Prize?
This paper identifies the determinants of the Nobel Prize Award. The analysis is analogous in spirit to Hamermesh and Schmidt (Econometrica, 2003) on the election of Econometric Society fellows. It is found that the number of citations, age and nationality have significant impacts on the odds of winning the Nobel. We provide the first statistical evidence that John Bates Clark medalists and individuals affiliated with the University of Chicago have a higher chance of winning the Prize.Nobel Prize; John Bates Clark Medal; Logit Model.
Perturb Initial Features: Generalization of Neural Networks Under Sparse Features for Semi-supervised Node Classification
Graph neural networks (GNNs) are commonly used in semi-supervised settings.
Previous research has primarily focused on finding appropriate graph filters
(e.g. aggregation methods) to perform well on both homophilic and heterophilic
graphs. While these methods are effective, they can still suffer from the
sparsity of node features, where the initial data contain few non-zero
elements. This can lead to overfitting in certain dimensions in the first
projection matrix, as training samples may not cover the entire range of graph
filters (hyperplanes). To address this, we propose a novel data augmentation
strategy. Specifically, by flipping both the initial features and hyperplane,
we create additional space for training, which leads to more precise updates of
the learnable parameters and improved robustness for unseen features during
inference. To the best of our knowledge, this is the first attempt to mitigate
the overfitting caused by the initial features. Extensive experiments on
real-world datasets show that our proposed technique increases node
classification accuracy by up to 46.5% relatively
Is Signed Message Essential for Graph Neural Networks?
Message-passing Graph Neural Networks (GNNs), which collect information from
adjacent nodes, achieve satisfying results on homophilic graphs. However, their
performances are dismal in heterophilous graphs, and many researchers have
proposed a plethora of schemes to solve this problem. Especially, flipping the
sign of edges is rooted in a strong theoretical foundation, and attains
significant performance enhancements. Nonetheless, previous analyses assume a
binary class scenario and they may suffer from confined applicability. This
paper extends the prior understandings to multi-class scenarios and points out
two drawbacks: (1) the sign of multi-hop neighbors depends on the message
propagation paths and may incur inconsistency, (2) it also increases the
prediction uncertainty (e.g., conflict evidence) which can impede the stability
of the algorithm. Based on the theoretical understanding, we introduce a novel
strategy that is applicable to multi-class graphs. The proposed scheme combines
confidence calibration to secure robustness while reducing uncertainty. We show
the efficacy of our theorem through extensive experiments on six benchmark
graph datasets
Current Optical Imaging Techniques for Brain Tumor Research: Application of in vivo Laser Scanning Microscopy Imaging with a Cranial Window System
Towards High Performance Anodes with Fast Charge/Discharge Rate for LIB Based Electrical Vehicles
Review-Based Domain Disentanglement without Duplicate Users or Contexts for Cross-Domain Recommendation
A cross-domain recommendation has shown promising results in solving
data-sparsity and cold-start problems. Despite such progress, existing methods
focus on domain-shareable information (overlapped users or same contexts) for a
knowledge transfer, and they fail to generalize well without such requirements.
To deal with these problems, we suggest utilizing review texts that are general
to most e-commerce systems. Our model (named SER) uses three text analysis
modules, guided by a single domain discriminator for disentangled
representation learning. Here, we suggest a novel optimization strategy that
can enhance the quality of domain disentanglement, and also debilitates
detrimental information of a source domain. Also, we extend the encoding
network from a single to multiple domains, which has proven to be powerful for
review-based recommender systems. Extensive experiments and ablation studies
demonstrate that our method is efficient, robust, and scalable compared to the
state-of-the-art single and cross-domain recommendation methods
Medial Meniscal Tears in Anterior Cruciate Ligament-Deficient Knees: Effects of Posterior Tibial Slope on Medial Meniscal Tear
PURPOSE: To evaluate the incidence of meniscal tears in patients with chronic anterior cruciate ligament (ACL)-deficient knees, and to determine the influence of posterior tibial slope (PTS) on medial meniscal tears in ACL-deficient knees. MATERIALS AND METHODS: We reviewed 174 patients (174 knees) with a mean age of 30.7 years who underwent ACL reconstruction for chronic ACL tears. We divided the patients into two groups: low group (135 knees with a PTS or =13degrees). RESULTS: The incidence of medial meniscus tears was 44% (77/174), and that of lateral meniscus tears was 35% (61/174). The mean PTS in patients with medial meniscal tears was 11.4degrees+/-3.0degrees, whereas that in patients without medial meniscal tears was 9.8degrees+/-2.4degrees. The incidence of meniscal tears was 57.8% (78/135) in the low group and 89.7% (35/39) in the high group (p or =13degrees is a risk factor for secondary medial meniscal tears in ACL-deficient knees. So, we suggest that PTS is one of the considerations for determining early ACL reconstruction to prevent secondary meniscal tears.ope
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