Generating Handwritten Chinese Characters using CycleGAN

Handwriting of Chinese has long been an important skill in East Asia. However, automatic generation of handwritten Chinese characters poses a great challenge due to the large number of characters. Various machine learning techniques have been used to recognize Chinese characters, but few works have studied the handwritten Chinese character generation problem, especially with unpaired training data. In this work, we formulate the Chinese handwritten character generation as a problem that learns a mapping from an existing printed font to a personalized handwritten style. We further propose DenseNet CycleGAN to generate Chinese handwritten characters. Our method is applied not only to commonly used Chinese characters but also to calligraphy work with aesthetic values. Furthermore, we propose content accuracy and style discrepancy as the evaluation metrics to assess the quality of the handwritten characters generated. We then use our proposed metrics to evaluate the generated characters from CASIA dataset as well as our newly introduced Lanting calligraphy dataset.Comment: Accepted at WACV 201

Immunogenicity of a Virus-Like-Particle Vaccine Containing Multiple Antigenic Epitopes of Toxoplasma gondii Against Acute and Chronic Toxoplasmosis in Mice

There is no effective protective vaccine against human toxoplasmosis, which is a potential threat to nearly a third of the world population. Vaccines based on virus-like particles (VLPs) have been highly successful in humans for many years, but have rarely been applied against Toxoplasma gondii infection. In this study, we inserted a B cell epitope (SAG182−102 or SAG1301−320), a CD8+ cell epitope (HF10 or ROP7), and a CD4+ cell epitope (AS15) of T. gondii into a truncated HBcΔ(amino acids1–149) particle to construct four chimeric VLP vaccine formulations, i.e., HBcΔH82, HBcΔH301, HBcΔ R82, and HBcΔ R301. When these chimeric HBc particles were expressed in Escherichia coli, they showed icosahedral morphology similar to that of the original VLPs and were evaluated as vaccine formulations against acute and chronic toxoplasmosis in a mouse model (BALB/c mice (H-2d). All these chimeric HBc VLPs induced strong humoral and cellular immune responses with high IgG antibody titers and interferon(IFN)-γ production. Only the mice immunized with HBcΔH82 showed prolonged survival time (15.6 ± 3.8 vs. 5.6 ± 0.8 days) against acute infection with RH tachyzoites and decrease in brain parasite load (1,454 ± 239 vs. 2,091 ± 263) against chronic infection with Prugniuad cysts, as compared to the findings for the control group. These findings suggest that HBc VLPs would act as an effective carrier for delivering effective multiple antigenic epitopes and would be beneficial for developing a safe and long-acting vaccine against toxoplasmosis

Conditional inferences and predictions based on copula models

Copulas combined with univariate distributions are a flexible tool for modeling distributions beyond Gaussian. Vine copulas based on a nested sequence of trees and a sequence of bivariate copulas can be used to construct high-dimensional copula models with flexible dependence structures. A multivariate model based on vine copulas assumes that variables are observed simultaneously in a sample. The contributions of this thesis are the new conditional inference and prediction methods based on vine copulas, including: (a) conditional distribution of one variable given others, (b) conditional distribution when the response variable is right-censored, (c) conditional distribution when some explanatory variables are nominal categorical. For (a), an algorithm is developed to compute arbitrary conditional distributions of one variable given the others for cross prediction from a single joint distribution fitted by vine copulas. An existing algorithm is also modified to simulate data from a vine copula given that one variable takes extreme values. For (b), in time-to-event and survival studies, the goal is to model the right-censored response variable with the explanatory variables to obtain point and interval predictions. The existing vine copula regression methodology is extended with a censored response variable and a set of discrete or continuous explanatory variables. For (c), for a nominal variable with three or more unordered categories, there is a PMF but no CDF. For use within vine copulas, the nominal variable is either converted to an ordinal variable, or encoded as binary dummy variables, similar to other regression models. The existing vine copula regression method is extended to allow some of the explanatory variables to be binary dummy variables with positive dependence converted from nominal variables. When fitting copula models with previous settings, there can be pairs of mixed continuous-discrete variables on the edges of a vine. The existing diagnostic methods for two continuous variables are not valid, and new diagnostic methods are developed. When parametric copula families do not provide adequate fits, nonparametric copulas can be used with adaptations for mixed continuous-ordinal variables. Allowing nonparametric copulas for mixed continuous-ordinal variables can improve the performance of vine copulas when applied to conditional inference.Science, Faculty ofStatistics, Department ofGraduat

Characteristics and outcomes of antiretroviral-treated HIV-HBV co-infected patients in Canada?

Abstract Background Hepatitis B (HBV) and Human Immunodeficiency Virus (HIV) share common risk factors for exposure. Co-infected patients have an increased liver-related mortality risk and may have accelerated HIV progression. The epidemiology and demographic characteristics of HIV-HBV co-infection in Canada remain poorly defined. We compared the demographic and clinical characteristics and factors associated with advanced hepatic fibrosis between HIV and HIV-HBV co-infected patients. Methods A retrospective cohort analysis was conducted using data from the Canadian Observational Cohort (CANOC) Collaboration, including eight sites from British Columbia, Quebec, and Ontario. Eligible participants were HIV-infected patients who initiated combination ARV between January 1, 2000 and December 14, 2014. Demographic and clinical characteristics were compared between HIV-HBV co-infected and HIV-infected groups using chi-square or Fisher exact tests for categorical variables, and Wilcoxon’s Rank Sum test for continuous variables. Liver fibrosis was estimated by the AST to Platelet Ratio Index (APRI). Results HBV status and APRI values were available for 2419 cohort participants. 199 (8%) were HBV co-infected. Compared to HIV-infected participants, HIV-HBV co-infected participants were more likely to use injection drugs (28% vs. 21%, p = 0.03) and be HCV-positive (31%, vs. 23%, p = 0.02). HIV-HBV co-infected participants had lower baseline CD4 T cell counts (188 cells/mm₃, IQR: 120–360) compared to 235 cells/mm₃ in HIV-infected participants (IQR: 85–294) (p = 0.0002) and higher baseline median APRI scores (0.50 vs. 0.37, p < 0.0001). This difference in APRI was no longer clinically significant at follow-up (0.32 vs. 0.30, p = 0.03). HIV-HBV co-infected participants had a higher mortality rate compared to HIV-infected participants (11% vs. 7%, p = 0.02). Conclusion The prevalence, demographic and clinical characteristics of the HIV-HBV co-infected population in Canada is described. HIV-HBV co-infected patients have higher mortality, more advanced CD4 T cell depletion, and liver fibrosis that improves in conjunction with ARV therapy. The high prevalence of unknown HBV status demonstrates a need for increased screening among HIV-infected patients in Canada.Other UBCNon UBCReviewedFacult