124 research outputs found
Robust c-Optimal Design for Estimating the Edp
Optimal design provides the most efficient design to study dose-response functions. It is often observed to adopt the four-parameter logistic model to describe the dose-response relationships in many dose finding trials. Under the four-parameter logistic model, optimal design to estimate the EDp accurately is presented. The EDp is the dose achieving 100p% of the maximum treatment effect. C-optimal design works the best to estimate the EDp, but the value of p must be predetermined in order to obtain the c-optimal design. Here we investigate the efficiency of c-optimal design to estimate the EDp for different values of p and present robust c-optimal design that works well for the changes in the value of p. Five different values of p are considered in this study: ED10, ED30, ED50, ED70, and ED90. The performance of the robust c-optimal design is obtained and compared to the c-optimal designs and traditional uniform designs
Understanding Effects of Algorithmic vs. Community Label on Perceived Accuracy of Hyper-partisan Misinformation
Hyper-partisan misinformation has become a major public concern. In order to
examine what type of misinformation label can mitigate hyper-partisan
misinformation sharing on social media, we conducted a 4 (label type:
algorithm, community, third-party fact-checker, and no label) X 2 (post
ideology: liberal vs. conservative) between-subjects online experiment (N =
1,677) in the context of COVID-19 health information. The results suggest that
for liberal users, all labels reduced the perceived accuracy and believability
of fake posts regardless of the posts' ideology. In contrast, for conservative
users, the efficacy of the labels depended on whether the posts were
ideologically consistent: algorithmic labels were more effective in reducing
the perceived accuracy and believability of fake conservative posts compared to
community labels, whereas all labels were effective in reducing their belief in
liberal posts. Our results shed light on the differing effects of various
misinformation labels dependent on people's political ideology
A Dual Stealthy Backdoor: From Both Spatial and Frequency Perspectives
Backdoor attacks pose serious security threats to deep neural networks
(DNNs). Backdoored models make arbitrarily (targeted) incorrect predictions on
inputs embedded with well-designed triggers while behaving normally on clean
inputs. Many works have explored the invisibility of backdoor triggers to
improve attack stealthiness. However, most of them only consider the
invisibility in the spatial domain without explicitly accounting for the
generation of invisible triggers in the frequency domain, making the generated
poisoned images be easily detected by recent defense methods. To address this
issue, in this paper, we propose a DUal stealthy BAckdoor attack method named
DUBA, which simultaneously considers the invisibility of triggers in both the
spatial and frequency domains, to achieve desirable attack performance, while
ensuring strong stealthiness. Specifically, we first use Discrete Wavelet
Transform to embed the high-frequency information of the trigger image into the
clean image to ensure attack effectiveness. Then, to attain strong
stealthiness, we incorporate Fourier Transform and Discrete Cosine Transform to
mix the poisoned image and clean image in the frequency domain. Moreover, the
proposed DUBA adopts a novel attack strategy, in which the model is trained
with weak triggers and attacked with strong triggers to further enhance the
attack performance and stealthiness. We extensively evaluate DUBA against
popular image classifiers on four datasets. The results demonstrate that it
significantly outperforms the state-of-the-art backdoor attacks in terms of the
attack success rate and stealthinessComment: 10 pages, 7 figures. Submit to ACM MM 202
Simulation study of BESIII with stitched CMOS pixel detector using ACTS
Reconstruction of tracks of charged particles with high precision is very
crucial for HEP experiments to achieve their physics goals. As the tracking
detector of BESIII experiment, the BESIII drift chamber has suffered from aging
effects resulting in degraded tracking performance after operation for about 15
years. To preserve and enhance the tracking performance of BESIII, one of the
proposals is to add one layer of thin CMOS pixel sensor in cylindrical shape
based on the state-of-the-art stitching technology, between the beam pipe and
the drift chamber. The improvement of tracking performance of BESIII with such
an additional pixel detector compared to that with only the existing drift
chamber is studied using the modern common tracking software ACTS, which
provides a set of detector-agnostic and highly performant tracking algorithms
that have demonstrated promising performance for a few high energy physics and
nuclear physics experiments
Virome and metagenomic analysis reveal the distinct distribution of microbiota in human fetal gut during gestation
Studies have shown that fetal immune cell activation may result from potential exposure to microbes, although the presence of microbes in fetus has been a controversial topic. Here, we combined metagenomic and virome techniques to investigate the presence of bacteria and viruses in fetal tissues (small intestine, cecum, and rectum). We found that the fetal gut is not a sterile environment and has a low abundance but metabolically rich microbiome. Specifically, Proteobacteria and Actinobacteria were the dominant bacteria phyla of fetal gut. In total, 700 species viruses were detected, and Human betaherpesvirus 5 was the most abundant eukaryotic viruses. Especially, we first identified Methanobrevibacter smithii in fetal gut. Through the comparison with adults’ gut microbiota we found that Firmicutes and Bacteroidetes gradually became the main force of gut microbiota during the process of growth and development. Interestingly, 6 antibiotic resistance genes were shared by the fetus and adults. Our results indicate the presence of microbes in the fetal gut and demonstrate the diversity of bacteria, archaea and viruses, which provide support for the studies related to early fetal immunity. This study further explores the specific composition of viruses in the fetal gut and the similarities between fetal and adults’ gut microbiota, which is valuable for understanding human fetal immunity development during gestation
Search for light dark matter from atmosphere in PandaX-4T
We report a search for light dark matter produced through the cascading decay
of mesons, which are created as a result of inelastic collisions between
cosmic rays and Earth's atmosphere. We introduce a new and general framework,
publicly accessible, designed to address boosted dark matter specifically, with
which a full and dedicated simulation including both elastic and quasi-elastic
processes of Earth attenuation effect on the dark matter particles arriving at
the detector is performed. In the PandaX-4T commissioning data of 0.63
tonneyear exposure, no significant excess over background is observed.
The first constraints on the interaction between light dark matter generated in
the atmosphere and nucleus through a light scalar mediator are obtained. The
lowest excluded cross-section is set at for
dark matter mass of MeV and mediator mass of 300 MeV. The
lowest upper limit of to dark matter decay branching ratio is
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