knowledge-graph multi-task-learning visual-reasoning visual-dialog visual-question-answering vision-and-language multimodal-deep-learning visual-storytelling multimodal-retrieval visual-grounding visual-commonsense-reasoning vision-and-language-navigation story-visualization image-text-matching vision-language-transformer image-text-retrieval vision-and-language-pre-training conditional-image-generation knowledge-enhanced-multimodal-learning knowledge-enhanced-vision-language