adv.in an unobtrusive manner

"messengers were moving unobtrusively over the jet-black mountain ranges, bearing confidential tidings from sheikhdom to sheikhdom"

DORMANT GUI BUTTONS RESIDE UNOBTRUSIVELY IN THE BACKGROUND UPON SELECTION
Learning users' interests by unobtrusively observing their normal behavior
AutoSense: unobtrusively wearable sensor suite for inferring the onset, causality, and consequences of stress in the field
Robust sensor fusion of unobtrusively measured heart rate.
The TAPS Project. 4: An observational study of the social life of long-stay patients.
An improved method of studying user-system interaction by combining transaction log analysis and protocol analysis
Ontological user profiling in recommender systems
Development of Concern for Others.
Ontological user profiling in recommender systems
Mind at ease puts a smile on the face: psychophysiological evidence that processing facilitation elicits positive affect.