From among a plurality of threads accessing a shared data object, one thread acquires a \u201cmaster\u201d status to arbitrate among the requests of competing threads during a given session of data access to the shared data object. A number of the embodiments employ a nasal pillow assembly including a frame that supports a nasal pillow sleeve and a clip that is slid over a flange of the fame to couple the nasal pillow sleeve to the frame. The area of halftone spots is partially increased in the virtual development region at a single gray-scale level. The electrical connector is mounted on the circuit board and is adapted to connect electrically the wireless transceiver to the electronic device.