Abstract: The present invention relates to a gray-level watermarking system, in which sub-band and codebook technique are applied, and the feature of progressive transformation is utilized so as to randomly and evenly distribute the watermark to the entire data with the robustness and the visibility reduced. A four-fold key system is developed with encrypted key to exact the watermark, thus forming a system capable of protecting internet-transmitted multimedia signals such as audio, video ones that are combined with the watermark from being detected or attacked.

Abstract: A method for recycling metals from swarf includes steps of removing oil in swarf by means of surfactant having a feature of strong hydrophilicity. The steps involves repeated stirring and washing, separating solid from liquid, and separating oil from water so as to force oil separate from the surface of solid, finishing all the steps in 10–30 minutes. Metals after finished the treatment may have only 1% of oil remained thereon, possible to be reused in metalworking. Oil and washing solution are also reusable after treated, so the method is effective both for treating waste and for recycling resources.

Abstract: A multi-DOF of positioning device has a main base, a fixed base, a translational Y-axial element, a translational X-axial element, multiple spring-mounted electromechanical actuating units, an elevating device, a rotational angle-adjusting assembly and an optical fiber holder. The translational Y-axial element is moveably mounted on the fixed base along a first axis. The translational X-axial element is moveably mounted on the translational Y-axial element along a second axis. The elevating device is moveably mounted on the main base along a third axis. The spring-mounted electromechanical actuating units are used to translationally move the fixed base, the translational Y-axial element and the elevating device relative to the corresponding structure along one of the axes. The rotational angle-adjusting assembly is mounted on the translational X-axial element and having a capability of rotating relative to the first, the second and the third axes.