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In recent years, the State Grid has actively promoted the construction of ubiquitous power Internet of things, so as to realize the interconnection and optimized management of things in the power system. Specifically, radio frequency identification (RFID) is the core technology for the construction of ubiquitous power Internet of things. Due to the advantages such as low-cost, battery-less, non-line-of-sight communication and long-distance communi-cation, RFID has been widely used in the power equipment management, the power inspection, and other applications. To inventory the items in the power equipment warehouse, the ID collection requires the fast tag identification. However, there are usually a large number of tags in the warehouse, and the signals from different tags will easily conflict with each other. Considering the dynamic framed ALOHA protocol conforming to EPC C1G2 standards in commodity RFID systems, this paper proposes a frame size adjustment algorithm based on Q-learning and neural network (denoted as QN-learning). The problem of adjusting the frame size can be modeled as the Markov decision process (MDP), the observed states are the number of different kinds of slots, i.e., empty slot, single slot and collision slot, and the actions correspond to the selected frame sizes. Therefore, the neural network-based Q-learning, named as QN-learning, is preferred to learn how to adjust the frame size adaptively. Referring to the learned strategy, the agent is able to select the global-optimal frame size with the latest observation. Simulation results show that the proposed QN-learning-based method performs well in terms of the frame size adjustment. Particularly, the QN-learning-based method can identify tags fast with high throughput and few query rounds, and it reduces the data transmission as well.

In industrial production, the orientation of facility components can indicate whether the facility is on a regular operating track. For example, when a component gets loose, the orientation variation of the component would exceed the normal range. A common approach for orientation measurement is to attach an inertial measurement unit (IMU) to the target device. However, the IMU requires additional power maintenance. This article presents LightGyro, a cheap and efficient batteryless scheme to measure the orientation, in which we attach a reflective film to the target device and use a camera to capture the light spot on the reflective film. The basic idea of LightGyro is to extract the light spots in the captured frame and use their pixel coordinates to infer the orientation. It is difficult to recognize a single light spot, because the spot lacks distinctive features. To solve the problem, we switch light sources on and off to regulate the appearance of light spots and utilize frame subtraction to extract light spots. The depth of field of light spot is lost in the process of camera projection, which is necessary for the orientation measurement. To address the issue, we propose a light array-based reflection model to extract the depth of field from the relative positions of multiple light spots. To the best of our knowledge, this is the first work to utilize reflection to measure orientation. Experiment results show that the orientation error of LightGyro decreases with the increasing length of the reflection route and the orientation error can achieve less than 1ˆ. [ABSTRACT FROM AUTHOR]

We aimed to investigate the cardiomyocyte-protective effects of bone marrow mesenchymal stem cells (BMSCs)-derived exosomes on ischemia/reperfusion (I/R)-injured rats and to explore the mechanisms. Cardiomyocytes were divided into control group, ischemia/reperfusion group (I/R group), ischemia/reperfusion+exosome group (I/R+Exo group) or ischemia/reperfusion+exosomes transfected with miR-101a-3p inhibitor group (I/R+Exo inhibitor group). MiR-101a-3p levels were lower in I/R and I/R+Exo inhibitor groups than in control and I/R+Exo groups. Apoptosis rate and cleaved caspase 3 expression were higher in I/R and I/R+Exo inhibitor groups. The levels of superoxide dismutase (SOD) in cardiomyocytes of I/R group and I/R+Exo inhibitor group were lower than those of control group and I/R+Exo group, and the levels of malondialdehyde (MDA) and the relative production of oxygen species clusters (ROS) in cardiomyocytes of I/R group and I/R+Exo inhibitor group were higher than those of control group and I/R+Exo group. The levels of interleukin-10 (IL-10), interleukin-6 (IL-6), tumour necrosis factor α (TNF-α), and nuclear factor κB (NF-κB) were higher in the I/R group and the I/R +Exo inhibitor group than in the control group and the I/R+Exo group. Bioinformatics analysis suggested that Pik3c3 is the most promising gene involved in miR-101a-3p-mediated apoptosis in cardiomyocytes, and in vitro experiments confirmed that low expression of miR-101a-3p significantly up-regulated the mRNA and protein expression levels of Pik3c3. BMSCs-derived exosomes have a protective effect on cardiomyocytes from I/R-injured rats, and the mechanism may be related to the inhibition of oxidative stress and inflammatory responses in cardiomyocytes by exosome-delivered miR-101a-3p.