M. Satyanarayanan. Pervasive computing: Vision and challenges. IEEE Personal Communications. Aug 2001. pp 10-17.
A. Pentland. Looking at people: sensing for ubiquitous and wearable
computing. IEEE Trans. on PAMI. 22 (1). Jan 2000. pp. 107-119.
This paper is a great introduction to/perspective on prior work and terminology for human centered sensing and understanding problems. Also, serves as a decent overview of prior work at the Media Lab.