Elastic deformation of bridge portions in an externally toothed gear and external teeth is suppressed, and this extends the life of tooth surfaces of external teeth 19, improves vibration characteristics, and markedly increases output torque while preventing a planetary gear device 11 from becoming large in size. An infrared camera may be in communication with the processor and may provide the processor with thermal-energy data for use by the processor in generating the image. Using random projections of the sensor data, along with a full waveform recording on one reference sensor, a sparse angle space scenario can be reconstructed, giving the number of sources and their DOA’s. As a result, the lead operable wall panel is locked into a straightened orientation.