An optical system with a first and second network tiers. Such an image decoding method comprises receiving an encoded bitstream including information of P and B frames, and executing motion compensation by synthesizing a predicted image of a current frame using motion vector information included in the encoded bitstream and a reference image which is a previously decoded image. Base portion is pivotally connected to the upper portion by link arms and secured by locking mechanisms. The handle rotates with the shaft relative to the tray, and is on one side of the tray with the shaft extending from an opposite side of the tray. In another embodiment, the biomass water slurry can be mixed with a coal water slurry to further optimize the carbon content and pumpability of the biomass slurry. In the optical pickup device, the liquid crystal device is constructed by sandwiching a liquid crystal molecule layer by a pair of transparent substrate.