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The micro-vision system is designed for micro-fabrication. This system with force sensor controls micro-fabrication operation. The focus is calculated by one order moment. Gradient evaluation function and frequency domain evaluation function are combined as evaluation function in auto-focus technology. Image definition evaluation function based on gradient is adopted in large step. Image definition evaluation function based on frequency-domain is adopted in small step. Search strategy adopts threshold method and curve fitting method. Edge invariant moment is to recognize objects. The system can measure the distance of three dimensions between the cutting tool and the work-piece. Then the micro-fabrication operation is completed.

The basic information required by trainers who wish to use video to achieve training outcomes is presented for those who are not experts at video production, do not have the time or the interest to become expert, do not have, and do not wish to develop, expertise in electronics and do not have access to sufficient organisational resources to hire an expert. The essential information needed to make experiences with video as productive, creative and problem‐free as possible is included.

The purpose of this paper is to propose a robotic system for percutaneous surgery. The key component in the system, a robotic arm that can manipulate a puncture needle is presented. The mechanical design, the motion control and the force control method of the robotic arm are discussed in the paper.

The arm with an arc mechanism placed on a 3D Cartesian stage is developed as a puncture needle manipulator to locate the position of the needle tip, tune the needle’s posture and actuate the puncture motion under the visual guidance of two orthogonal X-ray images of a patient by a surgeon. A focusing method by using two laser spots is proposed to automatically move the needle tip to a surgery entry point on the skin. A dynamics model is developed to control the position of the needle mechanism and an explicit force control strategy is utilized to perform the needle insertion.

With the surgical system, a surgeon can easily perform puncture operation by taking two orthogonal real-time X-ray images as a visual feedback and accurately navigating the needle insertion. The laser-guided focusing method is efficient in placement of the needle tip. The explicit force control strategy is proved to be effective for holding constant and stable puncture force in experiments.

The robotic arm has an advantage in easy redirection of the needle because the rotation and the translation are decoupled in the mechanism. By adopting simple laser pens and a well-developed kinematics model, the system can handle the entry point, locating task automatically. The focusing method and the force control method proposed in the paper are useful for the present system and could be intuitive for similar surgical robots.

This paper considers firms’ incentive to preserve compatibility between product generations in a duopoly setting. A firm may or may not maintain backward compatibility depending on its first period market share. Firms’ compatibility choices consequently will affect their pricing behaviors. Specifically, it is shown that under certain conditions both firms will preserve compatibility and act as local monopolist in the second period. Hence, backward compatibility becomes a tool for firms to relax second period price competition.