Abstract: An open-ear earphone includes a housing, a chamber is provided inside the housing, a speaker is provided inside the chamber and divides the chamber into a front chamber and a rear chamber. The housing is provided with a first sound hole and a second sound hole. The front chamber is communicated to the outside through the first sound hole, and the rear chamber is communicated to the outside through the second sound hole. The rear chamber includes a first volume down chamber and a second volume down chamber communicated to the first volume down chamber, and the first volume down chamber is located between the speaker and the second volume down chamber. The sound wave in backward motion generated by the speaker is transmitted to the outside from the second sound hole after being reduced by the first volume down chamber and the second volume down chamber.

Abstract: An open-ear Bluetooth® earphone includes an earphone body and a support frame. The support frame is configured to be plugged into a cavum concha of a wearer. The earphone body is provided with an audio source, and the support frame is installed on the earphone body and corresponds to the audio source. When in use, the support frame is configured to be firmly plugged into the cavum concha of the wearer to allow the earphone body to be worn on the ear of the wearer. The audio source corresponds to the ear canal of the wearer through the support frame, so that the sound emitted from the audio source is transmitted into the ear canal through the support frame. The audio source is directly opposite of the ear canal through the support frame to shorten the distance between the audio source and the ear canal.

Abstract: Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive, from a base station, a radio resource control (RRC) reconfiguration message. The UE may reestablish a radio link control (RLC) entity based on receiving the RRC reconfiguration message and transmit an indication that the RLC entity has been reestablished at the UE. In some cases, the UE may receive a data message prior to receiving an acknowledgment for the indication that the RLC entity is reestablished. For example, the base station may retransmit the RRC reconfiguration message prior to sending an acknowledgment status report. The UE may discard the data message based on the data message being received prior to receiving the acknowledgment.

Abstract: The present disclosure discloses a model-based architecture design method for an unmanned aerial vehicle (UAV) system, which aims to deal with challenges of changeable operational requirements, shortened design period, and decreased technical risks in a current UAS design process. A data-driven architecture development method is used. By establishing an architecture development framework of the UAS, a framework modeling process oriented to different viewpoints is designed, and modeling and simulation specifications based on SysML and Modelica are defined, such that design of the UAS starts from conception and confirmation of an operational concept. The method focuses on forward analysis and design of a system framework, and concept verification and metric closed-loop are carried out at an early stage of the design of the UAS by virtue of logic modeling and system simulation.