THE PREDICTION OF PHYSICAL ACTIVITY USING TREADMILL VIBRATION

A lot of treadmills detect physical activity by running speed which is only horizontal information, but vertical information is also important, such as impact and ground reaction force. This study tried to find out the relationship among the treadmill impact vibration, ground reaction force and human body impact vibration information on runner. Three college males were recruited to walk and run on treadmill at different speeds. Accelerometer on treadmill, accelerometer on human body and four load-cells were used to measure physical activity. The results showed that treadmill vibration was significantly correlated with body impact and ground reaction force. In the same speed, treadmill vibration at running was greater than walking. In order to predict whole physical activity more accurately, three-dimensional information should be used instead of speed only

The Dual-mediation Effect of Perceived Accuracy and Perceived Connectedness on Consumer Attitude Toward Social Network Advertising

Despite the importance of social media advertising, few studies have investigated the factors that influence its effectiveness (Jung, Shim, Jin, and Khang 2016). Because advertising on social media is a relatively new phenomenon (Okazaki and Taylor 2013), several studies are exploratory in nature and lack a solid theoretical framework (e.g., Campbell, Pitt, Parent, and Berthon 2011; Pehlivan, Sarican, and Berthon 2011; Sashittal, Sriramachandramurthy, and Hodis 2012; Waters and Jones 2011). For this reason, the present study examines the factors affecting consumers’ attitudes toward advertisements they view on social media. This paper draws on the stimulus-organism-response (S-O-R) model to investigate the dual mediation effect of perceived accuracy and perceived connectedness between endorsement from satisfied customers/review credibility/social influence and consumers’ attitudes toward social network advertising. Analysis of 1,031 valid responses to a survey show that endorsement from satisfied customers, review credibility, and social influence are antecedents of perceived accuracy and perceived connectedness. These variables are also antecedents of consumers’ attitudes toward social network advertising. In turn, perceived accuracy and connectedness partially mediate the relationships between endorsement from satisfied customers/review credibility/social influence and consumers’ attitudes toward social network advertising

High-Frequency Sea Level Variations Observed by GPS Buoys Using Precise Point Positioning Technique

In this study, sea level variation observed by a 1-Hz Global Positioning System (GPS) buoy system is verified by comparing with tide gauge records and is decomposed to reveal high-frequency signals that cannot be detected from 6-minute tide gauge records. Compared to tide gauges traditionally used to monitor sea level changes and affected by land motion, GPS buoys provide high-frequency geocentric measurements of sea level variations. Data from five GPS buoy campaigns near a tide gauge at Anping, Tainan, Taiwan, were processed using the Precise Point Positioning (PPP) technique with four different satellite orbit products from the International GNSS Service (IGS). The GPS buoy data were also processed by a differential GPS (DGPS) method that needs an additional GPS receiver as a reference station and the accuracy of the solution depends on the baseline length. The computation shows the average Root Mean Square Error (RMSE) difference of the GPS buoy using DGPS and tide gauge records is around 3 - 5 cm. When using the aforementioned IGS orbit products for the buoy derived by PPP, its average RMSE differences are 5 - 8 cm, 8 - 13 cm, decimeter level, and decimeter-meter level, respectively, so the accuracy of the solution derived by PPP highly depends on the accuracy of IGS orbit products. Therefore, the result indicates that the accuracy of a GPS buoy using PPP has the potential to measure the sea surface variations to several cm. Finally, high-frequency sea level signals with periods of a few seconds to a day can be successfully detected in GPS buoy observations using the Ensemble Empirical Mode Decomposition (EMD) method and are identified as waves, meteotsunamis, and tides

Drumhead Surface States and Topological Nodal-Line Fermions in TlTaSe2

A topological nodal-line semimetal is a new condensed matter state with one-dimensional bulk nodal lines and two-dimensional drumhead surface bands. Based on first-principles calculations and our effective k . p model, we propose the existence of topological nodal-line fermions in the ternary transition- metal chalcogenide TlTaSe2. The noncentrosymmetric structure and strong spin-orbit coupling give rise to spinful nodal-line bulk states which are protected by a mirror reflection symmetry of this compound. This is remarkably distinguished from other proposed nodal-line semimetals such as Cu3NPb(Zn) in which nodal lines exist only in the limit of vanishing spin-orbit coupling. We show that the drumhead surface states in TlTaSe2, which are associated with the topological nodal lines, exhibit an unconventional chiral spin texture and an exotic Lifshitz transition as a consequence of the linkage among multiple drumhead surface-state pockets.Comment: Related papers at http://physics.princeton.edu/zahidhasangroup/index.htm

Granger causal connectivity dissociates navigation networks that subserve allocentric and egocentric path integration

Studies on spatial navigation demonstrate a significant role of the retrosplenial complex (RSC) in the transformation of egocentric and allocentric information into complementary spatial reference frames (SRFs). The tight anatomical connections of the RSC with a wide range of other cortical regions processing spatial information support its vital role within the human navigation network. To better understand how different areas of the navigational network interact, we investigated the dynamic causal interactions of brain regions involved in solving a virtual navigation task. EEG signals were decomposed by independent component analysis (ICA) and subsequently examined for information flow between clusters of independent components (ICs) using direct short-time directed transfer function (sdDTF). The results revealed information flow between the anterior cingulate cortex and the left prefrontal cortex in the theta (4-7 Hz) frequency band and between the prefrontal, motor, parietal, and occipital cortices as well as the RSC in the alpha (8-13 Hz) frequency band. When participants prefered to use distinct reference frames (egocentric vs. allocentric) during navigation was considered, a dominant occipito-parieto-RSC network was identified in allocentric navigators. These results are in line with the assumption that the RSC, parietal, and occipital cortices are involved in transforming egocentric visual-spatial information into an allocentric reference frame. Moreover, the RSC demonstrated the strongest causal flow during changes in orientation, suggesting that this structure directly provides information on heading changes in humans