PerceptUI: LLM Agents as Human-Aligned Synthetic Users for UI/UX Evaluation

User interface (UI) and user experience (UX) evaluation is central to product development, yet reliable feedback still relies on recruiting human participants or running online A/B tests, making early-stage iteration slow and costly. In light of this, recent work has explored Multimodal Large Language Models as proxy evaluators. However, existing approaches either produce surface-level critiques or a judgment that reflects the model's own biases rather than the genuine response of a particular user. We introduce PerceptUI, a framework for persona-conditioned UI/UX evaluation that predicts how a specific user would answer interface-related questions and produces natural-language rationales. PerceptUI is trained in two stages: (i) contrastive reflection fine-tuning distills teacher-generated rationales by extracting lessons from human decisions, and (ii) a reflective prompt-evolution step from the model's own failure traces. Across multiple domains and datasets, PerceptUI achieves human-level realism, generalizes to unseen questions and personas, and yields population-level response distributions.

MobileCity: An Efficient Framework for Large-Scale Urban Behavior Simulation

Generative agents offer promising capabilities for simulating realistic urban behaviors. However, existing methods oversimplify transportation choices in modern cities, and require prohibitive computational resources for large-scale population simulation. To address these limitations, we first present a virtual city that features multiple functional buildings and transportation modes. Then, we conduct extensive surveys to model behavioral choices and mobility preferences among population groups. Building on these insights, we introduce a simulation framework that captures the complexity of urban mobility while remaining scalable, enabling the simulation of over 4,000 agents. To assess the realism of the generated behaviors, we perform a series of micro and macro-level analyses. Beyond mere performance comparison, we explore insightful experiments, such as predicting crowd density from movement patterns and identifying trends in vehicle preferences across agent demographics.