Classical equations of motion for three-dimensional σ-models in curved background are solved by a transformation that follows from the Poisson-Lie T-plurality and transform them into the equations in the flat background. Transformations of coordinates that make the metric constant are found and used for solving the flat model. The Poisson-Lie transformation is explicitly performed by solving the PDE's for auxiliary functions and finding the relevant transformation of coordinates in the Drinfel'd double. String conditions for the solutions are preserved by the Poisson-Lie transformations. Therefore we are able to specify the type of σ-model solutions that solve also equations of motion of three dimensional relativistic strings in the curved backgrounds. Simple examples are given

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This paper describes new methods and systems designed for application in upper extremity prostheses. An artificial upper limb with this system is a robot arm controlled by EMG signals and a set of sensors. The new multi-sensor system is based on ultrasonic sensors, infrared sensors, Hall-effect sensors, a CO₂ sensor and a relative humidity sensor. The multi-sensor system is used to update a 3D map of objects in the robot’s environment, or it directly sends information about the environment to the control system of the myoelectric arm. Occupancy grid mapping is used to build a 3D map of the robot’s environment. The multi-sensor system can identify the distance of objects in 3D space, and the information from the system is used in a 3D map to identify potential collisions or a potentially dangerous environment, which could damage the prosthesis or the user. Information from the sensors and from the 3D map is evaluated using a fuzzy expert system. The control system of the myoelectric prosthetic arm can choose an adequate reaction on the basis of information from the fuzzy expert system. The systems and methods were designed and verified using MatLab/Simulink. They are aimed for use as assistive technology for disabled people.

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