We are studying ways of recycling grinding fluid, supplying grinding fluid and electrode technology in the aim to develop Eco-friendly ELID grinding technology. As one elemental technology of this Eco-friendly ELID grinding technology, we developed a metal free electrode-conductive resinoid bonded wheel using RB ceramics as the conductive material. The prototyped grinding wheel was a #8000 RB ceramics bonded grinding wheel using diamond abrasives. Using this wheel, electrolytic dressing characteristics and grinding characteristics were investigated. Experimental results show that a non-conductive coating is formed on the wheel surface by electrolytic dressing, and this coating has greater frictional coefficient and wear amount than the bonding matrix. Grinding experiments of some hard and brittle materials were carried out using this grinding wheel, and it was found that a stable mirror surface finishing can be realized by adding ELID grinding.

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Zero-effort bilateral authentication was introduced recently to use a trusted wristwear to continuously authenticate a smartphone user. A user is allowed to use the smartphone if both wristwear and smartphone are determined to be held by the same person by comparing the wristwear's motion with the smartphone's input or motion, depending on the grip — which hand holds the smartphone and which hand provides the input. Unfortunately, the scheme has several shortcomings. First, it may work improperly when the user is walking since the gait can conceal the wrist's motions of making touches. Second, it continuously compares the motions of the two devices, which incurs a heavy communication burden. Third, the acceleration-based grip inference, which assumes that the smartphone is horizontal with the ground is inapplicable in practice. To address these shortcomings, we propose WearAuth, wristwear-assisted user authentication for smartphones in this paper. WearAuth applies wavelet-based multi-resolution analysis to extract the desired touch-specific movements regardless of whether the user is stationary or moving; uses discrete Fourier transform-based approximate correlation to reduce the communication overhead; and takes a new approach to directly compute the relative device orientation without using acceleration to infer the grip more precisely. In two experiments with 50 subjects, WearAuth produced false negative rates of 3.6% or less and false positive rates of 1.69% or less. We conclude that WearAuth operates properly under various usage cases and is robust to sophisticated attacks.

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