9,081 research outputs found
On the Robustness of Generative Retrieval Models: An Out-of-Distribution Perspective
Recently, we have witnessed generative retrieval increasingly gaining
attention in the information retrieval (IR) field, which retrieves documents by
directly generating their identifiers. So far, much effort has been devoted to
developing effective generative retrieval models. There has been less attention
paid to the robustness perspective. When a new retrieval paradigm enters into
the real-world application, it is also critical to measure the
out-of-distribution (OOD) generalization, i.e., how would generative retrieval
models generalize to new distributions. To answer this question, firstly, we
define OOD robustness from three perspectives in retrieval problems: 1) The
query variations; 2) The unforeseen query types; and 3) The unforeseen tasks.
Based on this taxonomy, we conduct empirical studies to analyze the OOD
robustness of several representative generative retrieval models against dense
retrieval models. The empirical results indicate that the OOD robustness of
generative retrieval models requires enhancement. We hope studying the OOD
robustness of generative retrieval models would be advantageous to the IR
community.Comment: 4 pages, submit to GenIR2
Exploring the Cosmic Reionization Epoch in Frequency Space: An Improved Approach to Remove the Foreground in 21 cm Tomography
Aiming to correctly restore the redshifted 21 cm signals emitted by the
neutral hydrogen during the cosmic reionization processes, we re-examine the
separation approaches based on the quadratic polynomial fitting technique in
frequency space to investigate whether they works satisfactorily with complex
foreground, by quantitatively evaluate the quality of restored 21 cm signals in
terms of sample statistics. We construct the foreground model to characterize
both spatial and spectral substructures of the real sky, and use it to simulate
the observed radio spectra. By comparing between different separation
approaches through statistical analysis of restored 21 cm spectra and
corresponding power spectra, as well as their constraints on the mean halo bias
and average ionization fraction of the reionization processes, at
and the noise level of 60 mK we find that, although the complex
foreground can be well approximated with quadratic polynomial expansion, a
significant part of Mpc-scale components of the 21 cm signals (75% for Mpc scales and 34% for Mpc scales) is lost because
it tends to be mis-identified as part of the foreground when
single-narrow-segment separation approach is applied. The best restoration of
the 21 cm signals and the tightest determination of and can be
obtained with the three-narrow-segment fitting technique as proposed in this
paper. Similar results can be obtained at other redshifts.Comment: 33 pages, 14 figures. Accepted for publication in Ap
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Governance Policy Evaluation in the United States during the Pandemic: Nonpharmaceutical Interventions or Else?
Scientific evidence suggests that nonpharmaceutical interventions (NPIs) effectively curb the spread of COVID-19 before a pharmaceutical solution. Implementing these interventions also significantly affects regular socioeconomic activities and practices of social, racial, and political justice. Local governments often face conflicting goals during policymaking. Striking a balance among competing goals during a global pandemic is a fine science of governance. How well state governments consume the scientific evidence and maintain such a balance remains less understood. This study employs a set of Bayesian hierarchical models to evaluate how state governments in the United States use scientific evidence to balance the fighting against the spread of COVID-19 disease and socioeconomic, racial, social justice, and other demands. We modeled the relationships between five NPI strategies and COVID-19 caseload information and used the modeled result to perform a balanced governance evaluation. The results suggest that governmental attitude and guidance effectively guide the public to fight back against a global pandemic. The more detailed spatiotemporally varying coefficient process model produces 612,000 spatiotemporally varying coefficients, suggesting all measures sometimes work somewhere. Summarized results indicate that states emphasizing NPIs fared well in curbing the spread of COVID-19. With over 1 million deaths due to COVID-19 in the United States, we feel the balance scale likely needs to tip toward preserving human lives. Our evaluation of governance policies is hence based on such an argument. This study aims to provide decision support for policymaking during a national emergency
(E)-3-Allylsulfanyl-N-(4-methoxybenzylidene)-5-(3,4,5-trimethoxyphenyl)-4H-1,2,4-triazol-4-amine
The title compound, C22H24N4O4S, adopts a trans configuration with respect to the C=N double bond. A weak intramolecular C—H⋯N hydrogen bond is observed between the N atom of the C=N double bond and its neighboring phenyl H atom. The crystal structure is stabilized by intermolecular C—H⋯N hydrogen bonds and C—H⋯π interactions
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