An Iterative Quality-Based Localization Algorithm for Ad Hoc Networks

An iterative quality-based algorithm for location discovery is presented which can be used in wireless ad hoc sensor networks. The algorithm will take the reliability of measurements into account and will produce a reliability index for every estimated location using a statistical approach. The algorithm can also work in a hybrid network with different kinds of distance measuring techniques. It will use the reliability of each of these methods in the final result. Satisfactory results can be achieved with this approach

Investigation of saturation effects in ceramic phosphors for laser lighting

We report observations of saturation effects in a Ce:LuAG and Eu-doped nitride ceramic phosphor for conversion of blue laser light for white light generation. The luminous flux from the phosphors material increases linearly with the input power until saturation effects limit the conversion. It is shown that the temperature of the phosphor layer influences the saturation power level and the conversion efficiency. It is also shown that the correlated color temperature (CCT), phosphor conversion efficiency and color rendering index (CRI) are dependent both on the incident power and spot size diameter of the illumination. A phosphor conversion efficiency up to 140.8 lm/W with CRI of 89.4 was achieved. The saturation in a ceramic phosphor, when illuminated by high intensity laser diodes, is estimated to play the main role in limiting the available luminance from laser-based lighting systems