AI-Based Positioning with Input Parameter Optimization in Indoor VLC Environments.

Indoorlocation-based service (LBS) technology has been emerged as a major research topic in recent years. Positioning technology is essential for providing LBSs. The existing indoor positioning solutions generally use radio-frequency (RF)-based communication technologies such as Wi-Fi. However, RF-based communication technologies do not provide precise positioning owing to rapid changes in the received signal strength due to walls, obstacles, and people movement in indoor environments. Hence, this study adopts visible-light communication (VLC) for user positioning in an indoor environment. VLC is based on light-emitting diodes (LEDs) and its advantage includes high efficiency and long lifespan. In addition, this study uses a deep neural network (DNN) to improve the positioning accuracy and reduce the positioning processing time. The hyperparameters of the DNN model are optimized to improve the positioning performance. The trained DNN model is designed to yield the actual three-dimensional position of a user. The simulation results show that our optimized DNN model achieves a positioning error of 0.0898 m with a processing time of 0.5 ms, which means that the proposed method yields more precise positioning than the other methods.

Chemical screen uncovers novel structural classes of inhibitors of the papain-like protease of coronaviruses.

The papain-like protease (PLpro) of coronaviruses is an attractive antiviral target to inhibit both viral replication and interference of the host immune response. We have identified and characterized three novel classes of small molecules, thiophene, cyanofuran, and triazoloquinazoline, as PLpro inhibitors. Thiophene inhibited the PLpro of two major coronaviruses, Middle East respiratory syndrome coronavirus (MERS-CoV) and severe acute respiratory syndrome coronavirus (SARS-CoV) including SARS-CoV-2, while cyanofuran and triazoloquinazoline more selectively inhibited MERS-CoV PLpro. Unlike GRL0617, a known PLpro inhibitor, all three compounds contain no naphthyl group but like GRL0617 were predicted to fit on the cleft near the BL2 loop. Docking studies further revealed that the location and direction of the binding determined their specificity to different coronaviruses. Together, our work demonstrates that the BL2 loop and nearby regions are outstanding druggable targets, and our three inhibitors can be applicable to the development of therapeutics for coronavirus infection.