Multi-task learning (MTL) is critical in real-world applications such as autonomous driving and robotics, enabling simultaneous handling of diverse tasks. However, obtaining fully annotated data for all tasks is impractical due to labeling costs. Existing methods for partially labeled MTL typically rely on predictions from unlabeled tasks, making it difficult to establish reliable task associations and potentially leading to negative transfer and suboptimal performance. To address these issues, we propose a prototype-based knowledge retrieval framework that achieves robust MTL instead of relying on predictions from unlabeled tasks. Our framework consists of two key components: (1) a task prototype embedding task-specific characteristics and quantifying task associations, and (2) a knowledge retrieval transformer that adaptively refines feature representations based on these associations. To achieve this, we introduce an association knowledge generating (AKG) loss to ensure the task prototype consistently captures task-specific characteristics. Extensive experiments demonstrate the effectiveness of our framework, highlighting its potential for robust multi-task learning, even when only a subset of tasks is annotated.

We present a novel method for Audio-Visual Question Answering (AVQA) in real-world scenarios where one modality (audio or visual) can be missing. Inspired by human cognitive processes, we introduce a Trans-Modal Associative (TMA) memory that recalls missing modal information (i.e., pseudo modal feature) by establishing associations between available modal features and textual cues. During training phase, we employ a Trans-Modal Recalling (TMR) loss to guide the TMA memory in generating the pseudo modal feature that closely matches the real modal feature. This allows our method to robustly answer the question, even when one modality is missing during inference. We believe that our approach, which effectively copes with missing modalities, can be broadly applied to a variety of multimodal applications.