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The automatic generation of dynamic facial expressions to transmit the internal states of a robot, such as mood, is crucial for communication robots. In contrast, conventional methods rely on patchwork-like replaying of recorded motions, which makes it difficult to achieve adaptive smooth transitions of the facial expressions of internal states that easily fluctuate according to the internal and external circumstances of the robots. To achieve adaptive facial expressions in robots, designing and providing deep structures that dynamically generate facial movements based on the affective state of the robot is more effective than directly designing superficial facial movements. To address this issue, this paper proposes a method for automatically synthesizing complex but organized command sequences. The proposed system generated temporal control signals for each facial actuator as a linear combination of intermittently reactivating decaying waves. The forms of these waves were automatically tuned to express the internal state, such as the arousal level. We introduce a mathematical formulation of the system using arousal expression in a child-type android as an example, and demonstrate that the system can transmit different arousal levels without deteriorating human-like impressions. The experimental results support our hypothesis that appropriately tuned waveform facial movements can transmit different arousal state levels, and that such movements can be automatically generated as superimposed decaying waves. [ABSTRACT FROM AUTHOR]

In this study, we applied argon plasma treatment to titanium surfaces with nanostructures deposited by concentrated alkali treatment and investigated the effects on the surface of the material and the tissue surrounding an implant site. The results showed that the treatment with argon plasma removed carbon contaminants and increased the surface energy of the material while the nanoscale network structure deposited on the titanium surface remained in place. Reactive oxygen species reduced the oxidative stress of bone marrow cells on the treated titanium surface, creating a favorable environment for cell proliferation. Good results were observed in vitro evaluations using rat bone marrow cells. The group treated with argon plasma exhibited the highest apatite formation in experiments using simulated body fluids. The results of in vivo evaluation using rat femurs revealed that the treatment improved the amount of new bone formation around an implant. Thus, the results demonstrate that argon plasma treatment enhances the ability of nanostructured titanium surfaces to induce hard tissue differentiation and supports new bone formation around an implant site. [ABSTRACT FROM AUTHOR]