FarSense: pushing the range limit of WiFi-based respiration sensing with CSI ratio of two antennas

International audienceThe past few years have witnessed the great potential of exploiting channel state information retrieved from commodity WiFi devices for respiration monitoring. However, existing approaches only work when the target is close to the WiFi transceivers and the performance degrades significantly when the target is far away. On the other hand, most home environments only have one WiFi access point and it may not be located in the same room as the target. This sensing range constraint greatly limits the application of the proposed approaches in real life. This paper presents FarSense-the first real-time system that can reliably monitor human respiration when the target is far away from the WiFi transceiver pair. FarSense works well even when one of the transceivers is located in another room, moving a big step towards real-life deployment. We propose two novel schemes to achieve this goal: (1) Instead of applying the raw CSI readings of individual antenna for sensing, we employ the ratio of CSI readings from two antennas, whose noise is mostly canceled out by the division operation to significantly increase the sensing range; (2) The division operation further enables us to utilize the phase information which is not usable with one single antenna for sensing. The orthogonal amplitude and phase are elaborately combined to address the "blind spots" issue and further increase the sensing range. Extensive experiments show that FarSense is able to accurately monitor human respiration even when the target is 8 meters away from the transceiver pair, increasing the sensing range by more than 100%. 1 We believe this is the first system to enable through-wall respiration sensing with commodity WiFi devices and the proposed method could also benefit other sensing applications

Tuning of catalytic sites in Pt/TiO₂ catalysts for the chemoselective hydrogenation of 3-nitrostyrene

The catalytic activities of supported metal nanoparticles can be tuned by appropriate design of synthesis strategies. Each step in a catalyst synthesis method can play an important role in preparing the most efficient catalyst. Here we report the careful manipulation of the post-synthetic heat treatment procedure—together with control over the metal loading—to prepare a highly efficient 0.2 wt% Pt/TiO2 catalyst for the chemoselective hydrogenation of 3-nitrostyrene. For Pt/TiO2 catalysts with 0.2 and 0.5 wt% loading levels, reduction at 450 °C induces the coverage of TiOx over Pt nanoparticles through a strong metal–support interaction, which is detrimental to their catalytic activities. However, this can be avoided by following calcination treatment with reduction (both at 450 °C), allowing us to prepare an exceptionally active catalyst. Detailed characterization has revealed that the peripheral sites at the Pt/TiO2 interface are the most likely active sites for this hydrogenation reaction.</p

Tuning of catalytic sites in Pt/TiO2 catalysts for chemoselective hydrogenation of 3-nitrostyrene

The catalytic activities of supported metal nanoparticles can be tuned by appropriate design of synthesis strategies. Each step in a catalyst synthesis method can play an important role in preparing the most efficient catalyst. Here we report the careful manipulation of the post-synthetic heat treatment procedure—together with control over the metal loading—to prepare a highly efficient 0.2 wt% Pt/TiO2 catalyst for the chemoselective hydrogenation of 3-nitrostyrene. For Pt/TiO2 catalysts with 0.2 and 0.5 wt% loading levels, reduction at 450 °C induces the coverage of TiOx over Pt nanoparticles through a strong metal–support interaction, which is detrimental to their catalytic activities. However, this can be avoided by following calcination treatment with reduction (both at 450 °C), allowing us to prepare an exceptionally active catalyst. Detailed characterization has revealed that the peripheral sites at the Pt/TiO2 interface are the most likely active sites for this hydrogenation reactio

Tuning of catalytic sites in Pt/TiO₂ catalysts for the chemoselective hydrogenation of 3-nitrostyrene

The catalytic activities of supported metal nanoparticles can be tuned by appropriate design of synthesis strategies. Each step in a catalyst synthesis method can play an important role in preparing the most efficient catalyst. Here we report the careful manipulation of the post-synthetic heat treatment procedure—together with control over the metal loading—to prepare a highly efficient 0.2 wt% Pt/TiO2 catalyst for the chemoselective hydrogenation of 3-nitrostyrene. For Pt/TiO2 catalysts with 0.2 and 0.5 wt% loading levels, reduction at 450 °C induces the coverage of TiOx over Pt nanoparticles through a strong metal–support interaction, which is detrimental to their catalytic activities. However, this can be avoided by following calcination treatment with reduction (both at 450 °C), allowing us to prepare an exceptionally active catalyst. Detailed characterization has revealed that the peripheral sites at the Pt/TiO2 interface are the most likely active sites for this hydrogenation reactio

An Experimental Study on the Establishment of Pulmonary Hypertension Model in Rats induced by Monocrotaline

Pulmonary hypertension is called PH for short. It is caused by the pulmonary artery vascular disease leading to pulmonary vascular resistance, and the increase right lung compartment load, which resulting in weakening or even collapse of the right ventricular function. The establishment of rat PH model under the action of monocrotaline is a repeatable, simple and accessible operation technique, which has been widely used in the treatment of pulmonary hypertension. This paper discusses the principle and properties of the PH model on rats under the monocrotaline action