People's body movements in daily face-to-face communication influence each other. For instance, during a heated debate, the participants use more gestures and other body movements, while in a calm discussion they use fewer gestures. This “coevolution” of interpersonal body movements occurs on multiple time scales, like minutes or hours. However, the multi-time-scale coevolution in daily communication is not clear yet. In this paper, we explore the minute-to-minute coevolution of interpersonal body movements in daily communication and investigate the characteristics of this coevolution. We present quantitative data on upper-body movements from thousand test subjects from seven organizations gathered over several months via wearable sensors. The device we employed measured upper-body movements with an accelerometer and the duration of face-to-face communication with an infrared ray sensor on a minute-by-minute basis. We defined a coevolution measure between two people as the number of per-minute changes of their body movement and compared the indices for face-to-face and non-face-to-face situations. We found that on average, the amount of people's body movements changed correspondingly for face-to-face communication and that the average rate of coevolution in the case of face-to-face communication was 3-4% higher than in the case of non-face-to-face situation. These results reveal minute-to-minute coevolution of upper-body movements between people in daily communication. The finding suggests that the coevolution of body movement arises in multiple time scales.

Random modulation refers to the changing of the MOSFET threshold voltage cell by cell. This paper claims it is essential in sub-2-V CMOS design because it reduces the sub-threshold leakage current even in the active and sleep modes as well as in the stand-by mode. We found that a gradated modulation scheme, which gradually changes the ratio of low- Vth cells according to the path-delay, is the best approach. To achieve the minimal leakage current, the way of determining the optimum pair of threshold voltages is also described. Experimental results for microprocessor show that gradated modulation reduces sub-threshold leakage current by 75% to 90% compared to conventional single-low-threshold voltage design without degrading the performance of the circuits.

Traditional imperfect fault coverage models only consider the coverage (including identification and isolation) of faulty components, and they do not consider the coverage of irrelevant (operational) components. One potential reason for the omission is that in these models the system is generally assumed to be coherent in which each component is initially relevant. In this paper, we first point out that an initially relevant component could become irrelevant afterwards due to the failures of some other components, and thus it is important to consider the handling of irrelevancy even the system is originally coherent. We propose an irrelevancy coverage model (IRCM) in which the coverage is extended to the irrelevant components in addition to the faulty components. The IRCM can not only significantly enhance system reliability by preventing the future system failures resulting from the not-covered failures of the irrelevant components, but may also play an important role in efficient energy use in practice by timely turning off the irrelevant components.