Human language learners are exposed to a trickle of informative, context-sensitive language, but a flood of raw sensory data. Through both social language use and internal processes of rehearsal and practice, language learners are able to build high-level, semantic representations that explain their perceptions. Here, we take inspiration from such processes of "inner speech" in humans (Vygotsky, 1934) to better understand the role of intra-agent speech in embodied behavior. First, we formally pose intra-agent speech as a semi-supervised problem and develop two algorithms that enable visually grounded captioning with little labeled language data. We then experimentally compute scaling curves over different amounts of labeled data and compare the data efficiency against a supervised learning baseline. Finally, we incorporate intra-agent speech into an embodied, mobile manipulator agent operating in a 3D virtual world, and show that with as few as 150 additional image captions, intra-agent speech endows the agent with the ability to manipulate and answer questions about a new object without any related task-directed experience (zero-shot). Taken together, our experiments suggest that modelling intra-agent speech is effective in enabling embodied agents to learn new tasks efficiently and without direct interaction experience.

The increasingly high display resolution of mobile devices imposes a further burden on energy consumption. Existing schemes manage either OLED or GPU power to save energy. This paper presents the design, algorithm, and implementation of a co-managing scheme called Duet, which automatically trades off perceptual quality for energy efficiency in accordance with static and dynamic visual acuity when users interact with mobile applications. The results of experiments conducted on a commercial smartphone with popular interactive apps show that Duet saves more energy while retaining better visual quality, compared with a joint scheme that simultaneously uses dynamic pixel disabling and dynamic resolution scaling to save OLED and GPU energy in isolation.

Abstract This paper presents unified formulas of the outage probability and the bit error rate (BER) for multiuser diversity with different multiple‐input multiple‐output (MIMO) schemes, including (1) transmit selective/receive selective (SC/SC); (2) transmit selective/receive maximum ratio combining (SC/MRC); and (3) space–time block codes (STBC) on Nakagami‐mfading channels. The exact closed‐form expressions can be derived for the outage probability with arbitrarymand for the BER with integerm. For a non‐integer fading parameter, the BER is expressible as a single infinite series of Gamma function. We also achieve simplified calculations for the performance at high SNR to gain insights regarding the factors determining the performance in fading. It is shown that the multiuser MIMO systems can achieve a full diversity order. The achieved results provide an analytical framework for the assessment of multiuser MIMO systems. All the analytical results are verified by Monte Carlo simulations. Copyright © 2010 John Wiley & Sons, Ltd.