This paper proposes an android-based application to help the users to navigate in finding books in the library easily and interactively. This navigation application is connected to a Bluetooth Low Energy (BLE) device that will emit an RSSI signal received by the Smartphone user and show the desired distance to the bookshelf position. The method of triangulation and mean filter were used to eliminate noise in the test environment to make the position of the bookshelf can be found precisely based on the RSSI BLE Beacon value. The test results showed the largest RSSI value for LOS conditions at -48dBm and NLOS at -63 dBm; while the lowest RRSI values for LOS conditions was at -84dBm and NLOS was at -96dBm.

The positive (minimal) realization problem for a class of singular discrete-time linear single-input, single-output systems with delays in state and delays in control is addressed. Solvability conditions for the positive (minimal) realization problem are established. It is shown that there exists a positive (minimal) realization of an improper transfer function T(z) = n(z) / d(z) if the coefficients of polynomial n(z) are non-negative and of the polynomial d(z) are non-positive except the leading one, which should be positive. A procedure for computation of the positive (minimal) realization of the transfer function is proposed and illustrated by an example.

This paper presents a position sensorless drive of non salient pole PM synchronous motors for all speeds including zero speed. Using adaptive Lyapunov design a new approach for the design of an observer is developed. The resulting scheme leads to a nonlinear full order observer for the motor states including the rotor speed. Assuming motor parameters known the design achieves stability with guaranteed region of attraction even at zero speed. The control method is made robust at zero and low speed by changing the direct vector current component to a value different from zero. In order to verify the applicability of the method the controller has been implemented and tested on a 800 W motor.