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8,051 results on '"Liu Xiaoming"'

153. FRCSyn-onGoing: Benchmarking and comprehensive evaluation of real and synthetic data to improve face recognition systems

Author

Melzi, Pietro, Tolosana, Ruben, Vera-Rodriguez, Ruben, Kim, Minchul, Rathgeb, Christian, Liu, Xiaoming, DeAndres-Tame, Ivan, Morales, Aythami, Fierrez, Julian, Ortega-Garcia, Javier, Zhao, Weisong, Zhu, Xiangyu, Yan, Zheyu, Zhang, Xiao-Yu, Wu, Jinlin, Lei, Zhen, Tripathi, Suvidha, Kothari, Mahak, Zama, Md Haider, Deb, Debayan, Biesseck, Bernardo, Vidal, Pedro, Granada, Roger, Fickel, Guilherme, Führ, Gustavo, Menotti, David, Unnervik, Alexander, George, Anjith, Ecabert, Christophe, Shahreza, Hatef Otroshi, Rahimi, Parsa, Marcel, Sébastien, Sarridis, Ioannis, Koutlis, Christos, Baltsou, Georgia, Papadopoulos, Symeon, Diou, Christos, Domenico, Nicolò Di, Borghi, Guido, Pellegrini, Lorenzo, Mas-Candela, Enrique, Sánchez-Pérez, Ángela, Atzori, Andrea, Boutros, Fadi, Damer, Naser, Fenu, Gianni, and Marras, Mirko

Published
2024
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165. Algorithms to estimate the lower bounds of recombination with or without recurrent mutations

Author

Fu Yun-Xin and Liu Xiaoming

Subjects
Biotechnology, TP248.13-248.65, Genetics, QH426-470
Abstract

Abstract Background An important method to quantify the effects of recombination on populations is to estimate the minimum number of recombination events, Rmin, in the history of a DNA sample. People have focused on estimating the lower bound of Rmin, because it is also a valid lower bound for the true number of recombination events occurred. Current approaches for estimating the lower bound are under the assumption of the infinite site model and do not allow for recurrent mutations. However, recurrent mutations are relatively common in genes with high mutation rates or mutation hot-spots, such as those in the genomes of bacteria or viruses. Results In this paper two new algorithms were proposed for estimating the lower bound of Rmin under the infinite site model. Their performances were compared to other bounds currently in use. The new lower bounds were further extended to allow for recurrent mutations. Application of these methods were demonstrated with two haplotype data sets. Conclusions These new algorithms would help to obtain a better estimation of the lower bound of Rmin under the infinite site model. After extension to allow for recurrent mutations, they can produce robust estimations with the existence of high mutation rate or mutation hot-spots. They can also be used to show different combinations of recurrent mutations and recombinations that can produce the same polymorphic pattern in the sample.

Published
2008
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176. Three essays in health economics

Author

Liu, Xiaoming, Moscelli, Giuseppe, and Koppensteiner, Martin F.

Abstract

This thesis contains three chapters on social and economic determinants of health. The first chapter investigates the causal effects of education on mental health. To address the endogeneity issues of education, the study uses Instrumental Variable strategy where actual years of education are instrumented by cohort-specific compulsory schooling years and its interaction with various childhood condition dummies. The estimates on the causal effects are sensitive to the choice of additional instruments. While majority of estimates suggest that there are no or only limited causal protective effects of education on mental health, the possibility of negative effects remains. The strong positive association between education and mental health could be explained by unobservable individual characteristics that affect education and mental health in the same direction. The second chapter studies whether more generous maternity leave protection in duration and payment can help decrease the incidence rates of pregnancy loss or termination (induced abortion, miscarriage and stillbirth) in low- and middle-income countries. Using a quasi-Difference-in-Differences approach, the study provides some evidence that increasing the generosity of maternity leave has the potential to reduce, in particular, the probability of induced abortion or miscarriage. The effects are stronger for Asian mothers who are working, mothers who have higher educational attainment and prestigious occupations, and mothers who were aged below 21 or above 30 at the realization of pregnancy outcomes. The last chapter explores how early life exposure to adverse shocks negatively affects the anthropometric outcomes of the second generation in Sub-Saharan African countries. The study reveals compelling evidence that mother's experience of negative rainfall shocks, particularly excessive drought, from in-utero to early adolescence significantly increases the probability that their offsprings suffer from impaired growth during early childhood. The effects are mainly driven by households residing in the rural areas and children who are located at the lower end of anthropometric distribution. There is also evidence that mothers' early life experience of negative rainfall shocks led to disadvantages in a variety of welfare outcomes persisting into marital households, which potentially contribute to next generation's underperformance in early life growth measures.

Published
2022
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177. Human distal airways contain a multipotent secretory cell that can regenerate alveoli

Author

Basil, Maria C, Cardenas-Diaz, Fabian L, Kathiriya, Jaymin J, Morley, Michael P, Carl, Justine, Brumwell, Alexis N, Katzen, Jeremy, Slovik, Katherine J, Babu, Apoorva, Zhou, Su, Kremp, Madison M, McCauley, Katherine B, Li, Shanru, Planer, Joseph D, Hussain, Shah S, Liu, Xiaoming, Windmueller, Rebecca, Ying, Yun, Stewart, Kathleen M, Oyster, Michelle, Christie, Jason D, Diamond, Joshua M, Engelhardt, John F, Cantu, Edward, Rowe, Steven M, Kotton, Darrell N, Chapman, Harold A, and Morrisey, Edward E

Subjects
Lung, Stem Cell Research, Stem Cell Research - Embryonic - Non-Human, Aetiology, 2.1 Biological and endogenous factors, Respiratory, Animals, Bronchioles, Cell Lineage, Ferrets, Humans, Mice, Multipotent Stem Cells, Pulmonary Alveoli, Pulmonary Disease, Chronic Obstructive, General Science & Technology
Abstract

The human lung differs substantially from its mouse counterpart, resulting in a distinct distal airway architecture affected by disease pathology in chronic obstructive pulmonary disease. In humans, the distal branches of the airway interweave with the alveolar gas-exchange niche, forming an anatomical structure known as the respiratory bronchioles. Owing to the lack of a counterpart in mouse, the cellular and molecular mechanisms that govern respiratory bronchioles in the human lung remain uncharacterized. Here we show that human respiratory bronchioles contain a unique secretory cell population that is distinct from cells in larger proximal airways. Organoid modelling reveals that these respiratory airway secretory (RAS) cells act as unidirectional progenitors for alveolar type 2 cells, which are essential for maintaining and regenerating the alveolar niche. RAS cell lineage differentiation into alveolar type 2 cells is regulated by Notch and Wnt signalling. In chronic obstructive pulmonary disease, RAS cells are altered transcriptionally, corresponding to abnormal alveolar type 2 cell states, which are associated with smoking exposure in both humans and ferrets. These data identify a distinct progenitor in a region of the human lung that is not found in mouse that has a critical role in maintaining the gas-exchange compartment and is altered in chronic lung disease.

Published
2022

179. Full-Velocity Radar Returns by Radar-Camera Fusion

Author

Long, Yunfei, Morris, Daniel, Liu, Xiaoming, Castro, Marcos, Chakravarty, Punarjay, and Narayanan, Praveen

Subjects
Computer Science - Computer Vision and Pattern Recognition
Abstract

A distinctive feature of Doppler radar is the measurement of velocity in the radial direction for radar points. However, the missing tangential velocity component hampers object velocity estimation as well as temporal integration of radar sweeps in dynamic scenes. Recognizing that fusing camera with radar provides complementary information to radar, in this paper we present a closed-form solution for the point-wise, full-velocity estimate of Doppler returns using the corresponding optical flow from camera images. Additionally, we address the association problem between radar returns and camera images with a neural network that is trained to estimate radar-camera correspondences. Experimental results on the nuScenes dataset verify the validity of the method and show significant improvements over the state-of-the-art in velocity estimation and accumulation of radar points., Comment: International Conference on Computer Vision, 2021

Published
2021

180. Reverse Engineering of Generative Models: Inferring Model Hyperparameters from Generated Images

Author

Asnani, Vishal, Yin, Xi, Hassner, Tal, and Liu, Xiaoming

Subjects
Computer Science - Computer Vision and Pattern Recognition, Computer Science - Artificial Intelligence, Computer Science - Machine Learning
Abstract

State-of-the-art (SOTA) Generative Models (GMs) can synthesize photo-realistic images that are hard for humans to distinguish from genuine photos. Identifying and understanding manipulated media are crucial to mitigate the social concerns on the potential misuse of GMs. We propose to perform reverse engineering of GMs to infer model hyperparameters from the images generated by these models. We define a novel problem, ``model parsing", as estimating GM network architectures and training loss functions by examining their generated images -- a task seemingly impossible for human beings. To tackle this problem, we propose a framework with two components: a Fingerprint Estimation Network (FEN), which estimates a GM fingerprint from a generated image by training with four constraints to encourage the fingerprint to have desired properties, and a Parsing Network (PN), which predicts network architecture and loss functions from the estimated fingerprints. To evaluate our approach, we collect a fake image dataset with $100$K images generated by $116$ different GMs. Extensive experiments show encouraging results in parsing the hyperparameters of the unseen models. Finally, our fingerprint estimation can be leveraged for deepfake detection and image attribution, as we show by reporting SOTA results on both the deepfake detection (Celeb-DF) and image attribution benchmarks., Comment: Accepted at Transactions on Pattern Analysis and Machine Intelligence

Published
2021

181. Radar-Camera Pixel Depth Association for Depth Completion

Author

Long, Yunfei, Morris, Daniel, Liu, Xiaoming, Castro, Marcos, Chakravarty, Punarjay, and Narayanan, Praveen

Subjects
Computer Science - Computer Vision and Pattern Recognition
Abstract

While radar and video data can be readily fused at the detection level, fusing them at the pixel level is potentially more beneficial. This is also more challenging in part due to the sparsity of radar, but also because automotive radar beams are much wider than a typical pixel combined with a large baseline between camera and radar, which results in poor association between radar pixels and color pixel. A consequence is that depth completion methods designed for LiDAR and video fare poorly for radar and video. Here we propose a radar-to-pixel association stage which learns a mapping from radar returns to pixels. This mapping also serves to densify radar returns. Using this as a first stage, followed by a more traditional depth completion method, we are able to achieve image-guided depth completion with radar and video. We demonstrate performance superior to camera and radar alone on the nuScenes dataset. Our source code is available at https://github.com/longyunf/rc-pda., Comment: IEEE Conference on Computer Vision and Pattern Recognition, 2021

Published
2021

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