225 research outputs found
A Bayesian Approach for Selecting Relevant External Data (BASE): Application to a study of Long-Term Outcomes in a Hemophilia Gene Therapy Trial
Gene therapies aim to address the root causes of diseases, particularly those
stemming from rare genetic defects that can be life-threatening or severely
debilitating. While there has been notable progress in the development of gene
therapies in recent years, understanding their long-term effectiveness remains
challenging due to a lack of data on long-term outcomes, especially during the
early stages of their introduction to the market. To address the critical
question of estimating long-term efficacy without waiting for the completion of
lengthy clinical trials, we propose a novel Bayesian framework. This framework
selects pertinent data from external sources, often early-phase clinical trials
with more comprehensive longitudinal efficacy data that could lead to an
improved inference of the long-term efficacy outcome. We apply this methodology
to predict the long-term factor IX (FIX) levels of HEMGENIX (etranacogene
dezaparvovec), the first FDA-approved gene therapy to treat adults with severe
Hemophilia B, in a phase 3 study. Our application showcases the capability of
the framework to estimate the 5-year FIX levels following HEMGENIX therapy,
demonstrating sustained FIX levels induced by HEMGENIX infusion. Additionally,
we provide theoretical insights into the methodology by establishing its
posterior convergence properties
Application of microstructured fiber sensor in the field of temperature detection
A fiber temperature sensor based on no core fiber-few mode fiber-no core fiber (NCF-FMF-NCF) is proposed. It consists of two segments of NCF and a segment of FMF, with the NCF fused at both ends of the FMF. Meanwhile, the lengths of the NCF and FMF were optimized by simulation simulations and experimental validation. The results show that the sensor has a high sensitivity to the external refractive index (RI) changes, and enables a wide range of ambient temperature measurement. A sensitivity of 0.09445nm/? was obtained in a temperature range of 25-70?. The sensor has the advantages of high stability, good linear fit and simple structure
Estimating International Migration Flows for the Asia-Pacific Region: Application of a Generation-Distribution Model
This is a repository for our paper in Migration Studies. The paper estimates annual flows of international migration among 53 populations in the Asia-Pacific region and four macro world regions from 2000 to 2019 using a generation-distribution framework.
This release contains:
Simulated input data
Code to produce the estimates
Final estimated flows in the paper
For questions with the code or request for all estimated flows with 1000 iterations, please email [email protected] or [email protected]
Neural-Network-Driven Method for Optimal Path Planning via High-Accuracy Region Prediction
Sampling-based path planning algorithms suffer from heavy reliance on uniform
sampling, which accounts for unreliable and time-consuming performance,
especially in complex environments. Recently, neural-network-driven methods
predict regions as sampling domains to realize a non-uniform sampling and
reduce calculation time. However, the accuracy of region prediction hinders
further improvement. We propose a sampling-based algorithm, abbreviated to
Region Prediction Neural Network RRT* (RPNN-RRT*), to rapidly obtain the
optimal path based on a high-accuracy region prediction. First, we implement a
region prediction neural network (RPNN), to predict accurate regions for the
RPNN-RRT*. A full-layer channel-wise attention module is employed to enhance
the feature fusion in the concatenation between the encoder and decoder.
Moreover, a three-level hierarchy loss is designed to learn the pixel-wise,
map-wise, and patch-wise features. A dataset, named Complex Environment Motion
Planning, is established to test the performance in complex environments.
Ablation studies and test results show that a high accuracy of 89.13% is
achieved by the RPNN for region prediction, compared with other region
prediction models. In addition, the RPNN-RRT* performs in different complex
scenarios, demonstrating significant and reliable superiority in terms of the
calculation time, sampling efficiency, and success rate for optimal path
planning.Comment: 9 pages, 8 figure
Precision education: A Bayesian nonparametric approach for handling item and examinee heterogeneity in assessment data
We propose a novel nonparametric Bayesian IRT model in this paper by
introducing the clustering effect at question level and further assume
heterogeneity at examinee level under each question cluster, characterized by
the mixture of Binomial distributions. The main contribution of this work is
threefold: (1) We demonstrate that the model is identifiable. (2) The
clustering effect can be captured asymptotically and the parameters of interest
that measure the proficiency of examinees in solving certain questions can be
estimated at a root n rate (up to a log term). (3) We present a tractable
sampling algorithm to obtain valid posterior samples from our proposed model.
We evaluate our model via a series of simulations as well as apply it to an
English assessment data. This data analysis example nicely illustrates how our
model can be used by test makers to distinguish different types of students and
aid in the design of future tests
Adaptively Placed Multi-Grid Scene Representation Networks for Large-Scale Data Visualization
Scene representation networks (SRNs) have been recently proposed for
compression and visualization of scientific data. However, state-of-the-art
SRNs do not adapt the allocation of available network parameters to the complex
features found in scientific data, leading to a loss in reconstruction quality.
We address this shortcoming with an adaptively placed multi-grid SRN (APMGSRN)
and propose a domain decomposition training and inference technique for
accelerated parallel training on multi-GPU systems. We also release an
open-source neural volume rendering application that allows plug-and-play
rendering with any PyTorch-based SRN. Our proposed APMGSRN architecture uses
multiple spatially adaptive feature grids that learn where to be placed within
the domain to dynamically allocate more neural network resources where error is
high in the volume, improving state-of-the-art reconstruction accuracy of SRNs
for scientific data without requiring expensive octree refining, pruning, and
traversal like previous adaptive models. In our domain decomposition approach
for representing large-scale data, we train an set of APMGSRNs in parallel on
separate bricks of the volume to reduce training time while avoiding overhead
necessary for an out-of-core solution for volumes too large to fit in GPU
memory. After training, the lightweight SRNs are used for realtime neural
volume rendering in our open-source renderer, where arbitrary view angles and
transfer functions can be explored. A copy of this paper, all code, all models
used in our experiments, and all supplemental materials and videos are
available at https://github.com/skywolf829/APMGSRN.Comment: Accepted to IEEE VIS 202
Finetuning Text-to-Image Diffusion Models for Fairness
The rapid adoption of text-to-image diffusion models in society underscores
an urgent need to address their biases. Without interventions, these biases
could propagate a distorted worldview and limit opportunities for minority
groups. In this work, we frame fairness as a distributional alignment problem.
Our solution consists of two main technical contributions: (1) a distributional
alignment loss that steers specific characteristics of the generated images
towards a user-defined target distribution, and (2) biased direct finetuning of
diffusion model's sampling process, which leverages a biased gradient to more
effectively optimize losses defined on the generated images. Empirically, our
method markedly reduces gender, racial, and their intersectional biases for
occupational prompts. Gender bias is significantly reduced even when finetuning
just five soft tokens. Crucially, our method supports diverse perspectives of
fairness beyond absolute equality, which is demonstrated by controlling age to
a young and old distribution while simultaneously debiasing
gender and race. Finally, our method is scalable: it can debias multiple
concepts at once by simply including these prompts in the finetuning data. We
hope our work facilitates the social alignment of T2I generative AI. We will
share code and various debiased diffusion model adaptors.Comment: preprint under revie
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